Abstracts

. 2022 Dec;37(Suppl 1):S15–S78.

Abstracts

PMCID: PMC9944600

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Category: Cardiology: Cardio 1: Agreement of ⁶⁸Ga-68 DOTANOC PET/CT with ¹⁸F-FDG PET/CT and cardiac resonance imaging in sarcoid patients with suspected cardiac involvement

Ritanshu Solanki ¹, Ashwani Sood ¹, Uma Debi ¹, Manphool Singhal ¹, Ajay Bahl ¹, Sahajal Dhooria ¹, Harmandeep Singh ¹, Saurabh Mehrotra ¹

Introduction: Cardiac sarcoidosis (CS) is difficult to diagnose and carries poorer outcome. Imaging modalities like cardiac magnetic resonance imaging (CMR), positron emission tomography (PET) and radionuclide scans have been shown to be helpful in the early detection of CS for its early diagnosis and treatment. ¹⁸F-FDG PET/CT in CS provides information related to inflammatory disease activity, early detection and therapy monitoring. Early CS is characterized by normal perfusion and increased focal FDG uptake, whereas tissue damage with abnormal perfusion and increased FDG uptake is seen in advanced CS. Scarring is the potential end-stage of CS, resulting in abnormal myocardial perfusion without FDG uptake. ⁶⁸Ga-DOTANOC having the high affinity for somatostatin receptors (SSTR) 2, 3 and 5 expressed in inflammatory cells in sarcoid granulomas does not have physiological myocardial uptake compared to ¹⁸F-FDG PET/CT. Therefore ⁶⁸Ga-DOTANOC may offer a better alternative to the non-specific FDG tracer uptake in CS imaging without the need for physiological suppression of FDG uptake prior to imaging.

Materials and Methods: A total of 19 patients who presented in the pulmonary out- patient department (OPD) with biopsy proven pulmonary sarcoidosis in which cardiac involvement was clinically suspected and patients with a primary cardiac abnormality (atrioventricular block, arrhythmia, or heart failure) who presented to the Cardiology OPD, in whom systemic sarcoidosis was diagnosed on the basis of clinical/histopathological features were included in this study. Patients underwent diagnostic tests with cardiac specific imaging procedures CMR, ¹³N-NH₃PET/CT for myocardial perfusion, ¹⁸F-FDG PET/CT for glucose metabolism and ⁶⁸Ga-DOTANOC PET/CT for abnormal SSTR expression in the myocardium. Findings of ¹⁸F-FDG PET/CT, CMR and ⁶⁸Ga-DOTANOC PET/CT were evaluated for the agreement among three imaging modalities.

Results: CMR could be done in only 15 out of 19 patients. CMR and ¹⁸F-FDG PET/CT were concordant in 13/15 (86.7%) patients and discordant in 2 (13.3%) with a substantial intermodality agreement with Cohen's kappa=0.732 and p value of 0.005 (statistically significant). CMR and ⁶⁸Ga-DOTANOC PET/CT were concordant in 12 (80.0%) patients and discordant in 3 (20.0%) with substantial intermodality agreement with Cohen's kappa=0.602 with p value of 0.019 (statistically significant) and ¹⁸F-FDG and ⁶⁸GaDOTANOC were concordant in 14/19 (73.6%) patients and discordant in 5/19 (26.3%) with moderate intermodality agreement with Cohen's kappa =0.469 and p value of 0.040 (statistically significant).

Conclusions: All three modalities; CMR, ¹⁸F-FDG PET/CT and ⁶⁸GaDOTANOC PET/CT have their own advantages and disadvantages. The physiological cardiac suppression with ¹⁸F-FDG PET/CT is a tedious process and may not be achieved in many patients, whereas SSTR imaging with ⁶⁸GaDOTANOCPET/CT has the advantage. In our study, although both ¹⁸F-FDG and ⁶⁸GaDOTANOC PET/CT had strong inter-modality agreement with CMR, the role of these imaging techniques is more complementary. SSTR imaging in CS with ⁶⁸Ga-DOTANOC PET/CT seems to be promising imaging modality and worth exploring. Though there is paucity of data to validate its role, but with more sample size and evidence, SSTR imaging has the potential to replace ¹⁸F-FDG PET/CT in the diagnosis, prognostication and response assessment.

Acknowledgments: This study was supported by the Indian Council of Medical Research Grant number 3/2/June-2021/PG-Thesis-HRD (15).

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Cardio 2: A prospective comparative study between ^99mTc MIBI myocardial perfusion single photon emission computed tomography and dobutamine stress echocardiography to detect viable myocardium in patients with coronary artery disease

D K Jha ¹, V Bohra ¹, A Mahato ², A Jain ², A Tiwari ²

Introduction: Ischemic heart disease (IHD) and stroke constitute majority of CVD mortality in India (83%). Because of high mortality rate, risk evaluation of patients with IHD by non invasive methods have become common. Among the various parameters, the distinction between reversible and irreversible ventricular dysfunction has important clinical implications as the dysfunctional but viable myocardium resumes contraction following revascularisation. Presently, PET using 18F-FDG is the gold standard for differentiating viable myocardial tissue from scar tissue. However PET assessment is limited to its availability, requires a perfusion scan and can have limited sensitivity in diabetics. On the other side SPECT and DSE are widely available. The aim of this study was to compare 99mTc MIBI SPECT and DSE in detecting viable myocardium in CAD patients and compare it to the gold standard 18F-FDG PET.

Materials and Methods: The study was a prospective study comparing the accuracy of resting MPI & DSE in diagnosing viable myocardium of CAD patients. The patients were also followed up with 18-FDG PET-CT which was taken as the gold standard. 50 consecutive patients who had severely impaired LV function and had been referred for a viability study were enrolled in the study.

Results: For analysis, a total of 800 myocardial segments from the 50 patients were evaluated (16 segment model). Regional contractile function, assessed by 2-D echo, demonstrated normal contraction in 250 (31.2%) segments and abnormal in 550 (68.8%) segments. The normal 250 segments were excluded from our evaluation. On segmental analysis with 99mTc MIBI, 413 (75%) out of the 550 dysfunctional segments were viable & 137 (25%) of the total 550 dysfunctional segments were labelled non-viable. On Low dose DSE (5-10mcg/kg/min), 407 (74%) of the 550 dysfunctional segments were viable & 143 (26%) of the total 550 dysfunctional segments were labeled non-viable. On 18F-FDG PET, viable dysfunctional segments with perfusion-metabolism mismatch were seen in 453 segments (82.4%) out of 550 segments. 97 segments (17.6%) out of 550 segments were non-viable.

Conclusion: Our study showed comparable results of resting 99mTc MIBI with DSE in detection of patients with viable myocardium. However, 18F-FDG PET detected more viable segments than both MIBI & DSE. In patients with moderate to severe ischemic LV dysfunction, resting MIBI is a useful tool for detection of viable myocardium where facility for DSE is not available or where contraindications exists, for eg. in very obese patients or with very high blood pressure not controlled on antihypertensives or patients with lung disease. However resting MIBI overestimates scar tissue and thus the negative results can be further evaluated by 18F-FDG PET for confirmation of viability.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Cardio 3: A novel quantitative scoring to predict improvement in left ventricular ejection fraction post revascularization in patients with ischemic cardiomyopathy

Surekha Yadav ¹, Arun Ravi John ¹, A G Pandit ¹, A K Dash ¹

Introduction: Despite considerable advances in prevention, detection and treatment strategies, CAD remains a significant cause of illness and mortality all around the globe. The three commonly available approaches proved effective in CAD with severe LV dysfunction are Optimized Medical therapy or revascularization by either Coronary Artery Bypass Grafting (CABG), Percutaneous Coronary Intervention (PCI). Prediction of the reversibility of chronic LV dysfunction, a powerful prognostic indicator in Coronary artery disease (CAD) continues to be a major clinical dilemma. Since revascularization is positively influenced by an “improvable element”, it is essential to carefully select patients who could benefit from the procedure as not every patient necessarily benefits from it. For detection of this 'functionally hibernating but definitely viable' myocardium, 18F-FDG viability imaging is the imaging modalities of choice. The purpose of the present study is to help the clinicians in identifying patients who would benefit from revascularization by developing a Scoring system and thereby defining crisp cut-off values as a standard protocol in myocardial viability imaging by 18F-FDG PET/CT. The objectives of this study are to 1) To predict improvement in left ventricular ejection fraction (LVEF) in patients with ischaemic cardiomyopathy 2) To correlate the number of viable and hibernating myocardium with the LVEF improvement post revascularization. And 3) To develop a scoring system for prognostication.

Materials and Methods: 51 patients were prospectively followed for 6 months as per inclusion criteria (>18 years, ≤ 45% LVEF, coronary angiography, with viable hibernating myocardium planned for revascularization (CABG/ PCI). Perfusion and metabolism studies were performed according to American Society of Nuclear Cardiology Guidelines. Scans analyzed by 2 nuclear medicine physicians independently and quantification done on 17 segment cardiac model. Uptake assessed using a scoring system - Normal FDG uptake ℒ1,>/= 50% of max uptake ℒ2, </= 50% ℒ3, No uptake ℒ4. LVEF was assessed with 2D- Echo at baseline and 6 months post revascularization. ROC analysis done for viable & hibernating segments and FDG PET score.

Results: Out of 867 segments analyzed, 294 were hibernating and 257were scarred. A moderate positive relationship between the number of viable segments detected and improvement in LVEF (r=0.564, p<0.001) was obtained. We found a moderate to low positive correlation between hibernating segments and LVEF improvement (r=0.390, p-0.006). Cut-off of >=12 viable segments was able to significantly predict this improvement (p-0.018) with sensitivity-78.9%, specificity-57.7%, PPV-57.7%, NPV-78.9%. Whereas >=5.5 hibernating segments were able to significantly predict improvement (p-0.018) with sensitivity-78.9%, specificity-76.9%, PPV-71.4%, NPV-83.3%. Moderate negative relationship between FDG PET-CT Score obtained and improvement was found (r=-0.592, p<0.001). Score of <28 was able to significantly predict LVEF improvement (p – 0.012) with a sensitivity- 57.9%, specificity ℒ80.8%, PPV-68.8%, NPV-72.4%.

Conclusion: Our study suggests that the diagnostic utility of total hibernating segments (Specificity-76.9% & PPV ℒ71.4%) is better than the diagnostic utility of total viable segments (Specificity-57.7%, PPV-57.7%) in predicting significant improvement in LVEF post revascularization from baseline to 6 months. We recommend predetermination of total viable and hibernating myocardial segments for predicting significant LVEF improvement post revascularization. Correlation between FDG-score and viable & hibernating segments with LVEF improvement has not yet been reported to the best of our knowledge. Although 18F-FDG PET-CT is a relatively costly procedure compared to DSE, CMR etc, it is recommended because the cost outweighs the risks associated with surgical and non surgical approaches of revascularization. This scoring system is the need of the hour as a potential tool to optimally recognize the subset of patients who are most likely to be benefitted from revascularization. It is imperative that the nuclear medicine physicians are well versed with the diagnostic utility of these tests.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Cardio 4: Molecular evaluation of myocarditis using ⁶⁸Ga DOTATATE and ¹⁸FDG in rest MPI normal but symptomatic, suspected acute myocarditis patients

Sutapa Rakshit ¹, Basant L Malpani ¹, Sunita Sonawane ¹, Nawab Singh Baghel ¹, A K Tyagi ¹

Objective: Myocarditis a rare inflammatory process of the heart muscle, can be acute or chronic in nature. Endomyocardial biopsy is the gold standard to prove myocarditis. ¹⁸FDG imaging is a probable potential diagnostic tool for early evaluation of myocarditis but it is nonspecific in nature as its uptake is seen in normal myocardium as well. ⁶⁸Ga DOTATATE, a somatostatin receptor based radiopharmaceutical which shows promising results for the assessment of myocardial inflammation as these receptors are expressed on immune cells. The objective is to compare¹⁸FDG and ⁶⁸Ga DOTATATE imaging for early diagnosis of myocarditis at molecular level.

Materials and Methods: Hospitalised patients, clinically suspected of acute myocarditis kept on carbohydrate-free diet for 48 hrs, were called after 6 hrs of fasting for ¹⁸FDG PET/CT scan. 50IU/kg heparin was injected 15 minutes prior to ¹⁸FDG injection (approximately 5 mCi). Patients were called again for ⁶⁸Ga DOTATATE PET/CT scan next day (approximately 2 mCi was injected) without any diet restrictions. Regional cardiac scan was carried out1 hr after injection on both the days using standard protocol on PET/CT system (GEMINI TF-16, PHILIPS). Seven patients (age: 18-57 yrs, male: 1, female: 6) underwent both the studies. Three ⁶⁸Ga DOTATATE patients' scans were acquired at 2 time-points to see washout of the tracer. Reconstruction was performed using RAMLA method. The data was visually analysed for both ¹⁸FDG and ⁶⁸Ga DOTATATE scans using fusion software. SUV_mean of liver, spleen, lung, bone marrow and heart were noted for both type of scans.

Results: Based on the visual assessment of the images, variable myocardial uptake pattern (patchy, diffuse and focal) and mediastinal lymph node uptake was observed in both the scans. In myocardium ¹⁸FDG uptake range (SUV_mean: 0.8-2.8) and ⁶⁸Ga DOTATATE uptake range (SUV_mean: 0.7-2.6) was noted. Average heart/lung (H/L) ratio for ¹⁸FDG was noted as 3.72±0.92 (mean, sd) and average heart/lung (H/L) ratio for DOTA was noted as 4.04±2.44. Average myocardium uptake ratio of ¹⁸FDG to ⁶⁸Ga DOTATAE 1.47±0.48.

Conclusion: ⁶⁸Ga DOTATATE is being reported in recent studies as marker for atherosclerotic inflammation. We observed that the SUV_mean of ⁶⁸Ga DOTATATE uptake in myocardium is less than that of ¹⁸FDG. The probable reason may be low density of receptors present in inflammatory cells of myocardium. We previously found that heart to lung ratio (H/L) of ⁶⁸Ga DOTATATE uptake as 1.82±0.19 in normal population in a retrospective study. Only one patient out of 7 shows uptake more than the threshold uptake of 1.8. Therefore, it is difficult to comment on the sensitivity of ⁶⁸Ga DOTATATE scan in myocarditis detection based on the results of our study population.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Cardio 5: Can machine learning decode hibernating myocardium from rest myocardial perfusion images?

Khangembam Bangkim Chandra ¹, Jasim Jaleel ¹, Arup Roy ¹, Priyanka Gupta ¹, Chetan Patel ¹

Introduction: The study aims to assess the feasibility of a machine learning (ML) approach to automatically predict hibernating myocardium from rest myocardial perfusion imaging (MPI).

Materials and Methods: Data of patients who underwent 99mTc-sestamibi MPI and 18F-FDG cardiac PET/CT for myocardial viability assessment from January 2017 to October 2022 were assessed. Replicable and stratified data sampling was employed on the data from January 2017 to July 2022 to allocate 80% (156) of the dataset to the training set and the remaining 20% (39) to the validation set. An independent dataset of 20 consecutive patients enrolled from August to October 2022 was used as the testing set for model evaluation. The gold standard for defining hibernating myocardium was the presence of mismatched perfusion-metabolism defect. Rest MPI data were processed on ECToolbox and polar maps were saved in JPEG format using NFile PMap tool. Image embedding was implemented on the polar map images using Google's InceptionV3, a convolutional 48-layered neural network with 2048 nodes in the penultimate layer, trained on 1.2 million images from the ImageNet repository. Pre-trained networks implementation from Tensorflow's model repository was used. Image features in the vector space were ranked by χ2 scoring method which assessed the dependence between the features and the target classes (hibernating or nonhibernating) as measured by the χ2 statistic. The 10 best-ranked features were selected for training the ML algorithms. 13 supervised ML algorithms were trained with 5-fold cross-validation on the training set and validated on the validation set. Hyperparameter optimization was implemented to yield the optimal performance of each algorithm. ML algorithms with a Log Loss <0.693 on training and validation steps were selected for model evaluation on the testing set. Various performance matrices of the algorithms were assessed including area under the curve (AUC), classification accuracy (CA), F1 score, precision, recall, and specificity.

Results: A total of 215 patients (193 males; mean age 56 ± 11 years) were enrolled in the study. Among the 13 ML algorithms, Decision Tree had a Log Loss of >0.693 in the training and validation steps. On training, 10 ML algorithms had AUC >0.800. These were Naive Bayes, Gradient Boosting (catboost), Neural Network (NN), Support Vector Machine (SVM), Random Forest (RF), Stochastic Gradient Descent (SGD), Extreme Gradient Boosting (xgboost), Gradient Boosting (scikit-learn), Logistic Regression (LR) and k-Nearest Neighbours (kNN). On validation, 9 ML algorithms had AUC >0.800 which included all the above algorithms except kNN. On model evaluation on the testing set, SVM, Gradient Boosting (scikit-learn), and Extreme Gradient Boosting Random Forest (xgboost) had AUC ≥0.70. SVM was the most optimal model with AUC 0.845, F1 Score 0.857, and could decode hibernating myocardium in 12/14 (85.7%) patients with an overall accuracy of 80.0% (16/20). The rest of the models failed to generalize well on the testing set.

Conclusion: Machine learning can decode the presence of hibernating myocardium from rest myocardial perfusion images. SVM was the most consistent and optimal model for the purpose with good generalization ability.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Cardio 6: Association between right ventricular ejection fraction calculated by first pass radionuclide ventriculography and surrogate markers of right ventricular function assessed by echocardiography in dilated cardiomyopathy patients – A comparative study

S Dasgupta ¹, M Mudalsha ¹, S Singh ¹, T Lukose ¹, H Bansal ¹, S Krishna ¹, R Kote ¹, M Reddy ¹

Introduction: (1) To correlate Right Ventricular Ejection Fraction (RVEF) calculated by First Pass Radionuclide Ventriculography (FPRNV) to Tricuspid Annular Plane Systolic Excursion (TAPSE) calculated by echocardiography in a subset of dilated cardiomyopathy (DCM) patients. (2) To correlate Left Ventricular Ejection Fraction (LVEF) calculated by FPRNV and echocardiography.

Materials and Methods: 28 patients with echocardiography diagnosed Dilated Cardiomyopathy (LVEF<45% and LVEDD >2.7cm/m2 or >117% predicted value corrected for age and BSA) >18 years of age were recruited for the purpose of this ongoing study after informed consent. A case record form with the detailed history including medications and co-morbidities were documented. Echocardiography findings including TAPSE, PACT and LVEF were documented. For the purpose of FPRNV, in-vivo RBC labelling was used. FPRNV was assessed by bolus administration of 20 mCi of Tc-99m pertechnetate through an 18G IV catheter in the right ante cubital vein followed by 10ml normal saline chase under a NM 670 DR SPECT/CT by GE healthcare in 25° RAO projection. Data was acquired in frame mode with cardiac cycle divided in 24 bins for an average 8 million counts in a 64*64 matrix and a 20% energy window centred at 140 keV. Studies with full width at half maximum (FWHM) of the bolus transit in the superior vena cava less than three seconds were included for analysis. RVEF was calculated by the dual ROI method. Sinus beats with end diastolic counts >50% of maximum end-diastolic counts was used. LVEF was subsequently calculated by Multigated Acquisition (MUGA). The best septal (LAO) projection with caudal tilt was used. TAPSE calculated by echocardiography and RVEF calculated by FPRNV was expressed as mean ± SD and compared by linear regression analysis. LVEF computed by both modalities was similarly compared.

Results: TAPSE calculated by doppler echocardiography showed positive correlation amongst the echocardiography parameters with RVEF by FPRNV (r=0.76, CI=95%) in DCM patients. LVEF computed by both modalities also showed moderate positive correlation (r=0.67). The mean value of Inline graphic was 2.30 (SD=0.68).

Conclusion: Patients with DCM with RVEF<38% and LVEF <30% have increased 1st year mortality figures. Further LVAD placement can further compound right hear failure. Further RVEF >35% has been shown as the strongest predictor of survival in DCM patients in previous multivariate models with LVEF. Our study shows strong positive correlation between RVEF with TAPSE and PACT as well as LVEF by both modalities. Long term goal is to expand population size and shed better light on the elusive subject of RV function assessment including a multimodality approach in better guiding management and prognostic evaluation of DCM patients and beyond.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Cardio 7: Role of hybrid single photon emission computed tomography myocardial perfusion imaging/computed tomography coronary angiography in detecting coronary artery disease in patients with dilated left ventricle and reduced ejection fraction

Brinda Ravichandran ¹, Madhusudhanan Ponnusamy ¹

Introduction: DMCP is a diagnosis of exclusion, it is essential to rule out ischemic causes in these patients presenting with LV dysfunction. Though ICA is the investigation of choice, the complications associated with it are quite high in these patients with reduced ejection fraction. Hence, we have fused non-invasive diagnostic modalities like SPECT MPI and CTCA to assess the functional and anatomical status of the myocardium and coronaries, respectively. The study aim was to to detect the proportion of CAD in patients with dilated left ventricle (LV) and reduced EF based on image patterns on hybrid (SPECT MPI /CTCA) imaging.

Materials and Methods: 30 patients with dilated LV defined as LV end-systolic diameter >40 mm or LV end-diastolic diameter >55 mm on echocardiography and reduced LVEF defined as <40% on echocardiography were recruited for the study from July 2020 to June 2022. All patients underwent stress SPECT MPI and CTCA within a period of one week. The three-dimensional LV myocardium and coronary tree were fused using CardiacIQ fusion software. The proportion of patients with matched or unmatched perfusion and structural defects was evaluated.

Results: Out of 30 patients, 7 (23%) patients had abnormal MPI findings, with most of them having severe perfusion defects (n = 4) involving a larger extent (n = 7) of the left ventricular myocardium. Nineteen patients (63%) had normal coronaries. Of the abnormal CTCA results, the most common coronary artery found to be stenotic was LAD (n = 7, 23%). Stenosis of more than 50% of the coronary lumen was found in 5 patients (17%). Of the 7 patients with abnormal findings on hybrid imaging, 5 (17%) patients had matched defects in SPECT MPI and CTCA, with most of the defects corresponding to the LAD territory (n = 4). Two (6%) patients had perfusion defects but normal coronaries (unmatched findings). Overall, 23% (95% confidence interval: 8 to 38%) of patients had coronary artery disease as defined by matched and unmatched perfusion defects in hybrid imaging.

Conclusion: Hybrid SPECT MPI/CTCA imaging is feasible in patients with dilated LV cavity and reduced EF. Integrated SPECT MPI and CTCA imaging helped visualize both coronary lesions and perfusion defects and therefore enhanced confidence in reporting CAD.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Category: Endocrinology: Endo 1: Comparative study of functional and structural imaging modalities including ⁶⁸Ga DOTATATE PET/ CT, ¹⁸F FDG PET/ CT, ¹³¹I mIBG and CECT in patients of pheochromocytomas and paragangliomas

C Ashwini ¹, Saba Samad Memon ¹, Anurag R Lila ¹, Tushar R Bandgar ¹, Sandip Basu ¹, Ramesh Asopa ¹, Gaurav Malhotra ¹

Introduction: To compare semi-quantitative parameters among functional and anatomical imaging modalities in patients of paragangliomas and phaeochromocytomas including lesion based, patient based, region based and subgroup analysis. To determine correlation amongst SUVmax, Metabolic Tumor Volume (MTV), Total Lesion Glycolysis (TLG), and SUVmean of ¹⁸F FDG PET CT &⁶⁸Ga DOTATATE PET CT in prediction of malignancy. To find correlation between tumor markers and semi-quantitative parameters of ¹⁸F FDG PET CT, ⁶⁸Ga DOTATATE PET CT, and Tumor/ Liver ratio of ¹³¹I mIBG scan.

Materials and Methods: This prospective study included 33 patients who underwent CECT and atleast 2 out of 3 functional scans (⁶⁸Ga DOTATATE PET/ CT, ¹⁸F FDG PET/ CT and ¹³¹I mIBG scan) as per the institution protocol. Patient wise, lesion wise and region wise analysis was performed. Benign and malignant lesions were analysed separately. Semiquantitative parameters were estimated. Tumor to liver ratio of ¹³¹I mIBG scan was calculated and correlated with semiquantitative parameters of other functional scans and tumor markers.

Results: 14 of 33 patients [16 males (age range: 25 to 64 years; median age: 47 years) and 17 females (age range: 17 to 60 years; median age: 40 years)] were diagnosed as pheochromocytomas while 19 were diagnosed as paragangliomas. Patientwise detection rate of CECT (100%) and ⁶⁸Ga DOTATATE PET/ CT (96%) was comparable, and better than that of ¹⁸F FDG PET/ CT (86%) and ¹³¹I mIBG scan (83%). Lesionwise detection rate of ⁶⁸Ga DOTATATE PET/ CT (90.78%) was better as compared to other imaging modalities. For benign lesions, detection rate of CECT (96.8%) and ⁶⁸Ga DOTATATE PET/ CT (96.5%) was comparable, and better than other modalities. For malignant lesions, detection rate of ⁶⁸Ga DOTATATE PET/ CT (87.2%) was better than other imaging modalities. In region-wise analysis for metastatic lesions, ⁶⁸Ga DOTATATE PET/ CT had significantly higher sensitivity for skeletal (85.7%) and head and neck lesions (80%) as compared to other functional scans. ROC curve of ⁶⁸Ga DOTATATE PET/ CT to predict malignancy showed SUVmax while ROC curve of ¹⁸F FDG PET/ CT showed TLG and SUVmean to be better predictors of malignancy. In cases of pheochromocytomas and in retroperitoneal paragangliomas, TLG of ⁶⁸Ga DOTATATE PET/CT showed strong correlation with tumor to liver ratio of ¹³¹I mIBG scan. In correlation with tumor markers, PFMN and PFNMN showed moderate positive correlation with tumor to liver ratio of ¹³¹I mIBG scan.

Conclusion: ⁶⁸Ga DOTATATE PET/ CT should be considered as initial investigation of choice of PPGL. ⁶⁸Ga DOTATATE PET/CT and CECT are equally sensitive for benign, however former is nearly twice as sensitive for detection of malignant lesions. Therefore, it should be the modality of choice in patients who have suspicion of metastatic involvement. For Head and Neck paragangliomas, ⁶⁸Ga DOTATATE PET/ CT appears to be superior to other imaging modalities.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Endo 2: Profiling of “bilateral diffuse pattern” of lung metastasis in thyroid cancer on radioiodine scan

Ashwini Kalshetty ¹

Introduction: Lung metastasis in well differentiated thyroid cancer is a relatively common presentation. Diagnostic radio-iodine scans sometimes show a bilateral diffuse pattern without anatomic lesions which was considered favourable for treatment response in paediatric population. However, the clinical significance of this unique feature on radioiodine scan is not studied extensively, especially in adult cases. Therefore, an attempt to understand the clinical characteristics associated with pattern was undertaken.

Methods: A cohort of 31 thyroid cancer cases who had bilateral diffuse pattern of lung metastasis on radio-iodine scan between 1st June 2021 to 1st July 22 were included in the study. Their demographic, clinical and laboratory data were noted. Clinical, imaging, laboratory response was noted in cases in whom multiple radioiodine therapies were given.

Results: There were 14 females and 17 males in the group with age range of 5-79 years. Almost all i.e 29 of 31 cases were Papillary thyroid carcinoma (PTC, including encapsulated follicular variant PTC) while 2 were Follicular thyroid carcinoma (FTC). All cases had elevated stimulated Tg (range: 141- 1420 ng/ml). 16 of 31 cases showed macronodular pattern on HRCT. There were 24 cases who had atleast received 3 radioiodine therapies. 15 cases showed stable disease, 4 cases showed partial response while 2 patients showed disease progression after receiving cumulative dose of > 550 mCi RAI therapies. Two paediatric and 1 adult cases who had normal HRCT, showed complete response (CR) on imaging and normalisation of simulated Tg after 3# of radio-iodine therapy (CR after cumulative dose > 390 mCi and 540 mCi respectively).

Conclusion: The “bilateral diffuse pattern” of lung metastasis in thyroid cancer on radioiodine scan frequently occurs in PTC, especially in younger age group and can be a predictor for treatment planning and treatment response. These cases usually require multiple high dose radioiodine therapies. However, large groups and longer follow up duration are needed for validation as an imaging derived prediction marker.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Endo 3: Development of thyroid uptake calculation software using deep learning algorithm

Abhishek Kumar ¹, Sushama Awasare ¹, K Biju ¹, N S Baghel ¹, A K Tyagi ¹

Introduction: Nuclear Medicine imaging modality is one of the tools to provide functional information of specific organ of the patients. Qualitative and quantitative information for thyroid functional assessment is carried out using this tool for thyroid management. Imaging data can be used by Machine Learning algorithms like Deep Learning (DL), which are evolving rapidly with a great success rate and in a very broad spectrum of applications. These DL models use Neural Engines and Neural Networks to identify the data representations based on mathematics and algorithms which is called threshold logic. The objective of this study is to apply a practical frame-work of the automated detection of Region of Interest (ROI) in the image for thyroid uptake calculation.

Materials and Methods: Total 36 patients, referred for the thyroid uptake and scan study, were included in this study. The patients were administered 0.925 MBq (25 μCi) 131 I Capsule orally for thyroid scan. The data was transferred in Digital Imaging and Communications in Medicine (DICOM) format from Gamma Camera SPECT system to window based PC. Uptake was calculated using Thyroid Uptake probe and gamma camera at 2 hrs and 24 hrs. However, 24 hrs. uptake data was used for analysis in this study. An artificial intelligence (AI) algorithm is used for automated ROI detection and “Doughnut Background subtraction” on processed DICOM images obtained from the Gamma camera fitted with medium energy all purpose (MEAP) collimator. The uptake measurement obtained by these two methods were compared. The methodology involved in the ROI detection were alpha and gamma channel adjustments and then using canny edge detection which is further passed to an ML (Machine Learning) model to adjust the shape of the ROI according to the specific organ to remove possible radiations coming from nearby organs. The ML model is continuously trained over the dataset from each patient and continues to improve its accuracy.

Results: Comparison was done between uptake values obtained with probe system and with the values obtained using DL algorithm on processed DICOM images of the patient. It is found that the correlation coefficient values were lying in the range of 0.946-0.996. Accurate ROIs were drawn successfully with the help of developed algorithm.

Conclusion: The developed algorithm for calculation of thyroid uptake is very accurate and reproducible. This is fully automated technique in which inter-operator and the inter-facility variability of ROI setting is completely eliminated. This is a robust technique which is user friendly and will be very useful for uptake calculation, which provides quantitative information of thyroid organ.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Endo 4: Preparation of 68Ga-NODAGA-RGD dimer as a radiotracer for tumor imaging at RMC

Ashok R Chandak ^1,², P Verma ², G Malhotra ², M K Ray ²

Introduction: The aim of the present work was radiolabeling and in-vivo evaluation of NODAGA-[RGD(y)K]₂ with ⁶⁸Ga³⁺ eluted from a commercial ⁶⁸Ge/⁶⁸Ga generator and used clinically for tumor imaging (thyroid cancer). Targeting tumor cells or tumor vasculature by peptides is a promising strategy for delivering cytotoxic drugs for cancer therapy. The Arg-Gly-Asp (RGD) dimeric sequence has been known to bind effectively with the α_vβ₃ integrin receptors expressed on the surface of angiogenic blood vessels or tumour cells. This study deals with preparation of ⁶⁸Ga-NODAGA-RGD dimer, its physicochemical and preclinical study in normal rat and clinical evaluation in follicular thyroid carcinoma patient.

Materials and Methods: The NODAGA-[RGD(y)K]₂ (ABX) was used (25 μg) for labeling with ⁶⁸Ga obtained from ⁶⁸Ge/⁶⁸Ga (50 mCi/1850MBq, itG/itM) generator. The synthesis was carried out aseptically using Eckert & Ziegler automated module as per the RPC approved protocol. The products were evaluated for physicochemical characteristic, stability and biodistribution in normal rat using PET camera. In vivo study was done in 50 years old male with follicular thyroid carcinoma and comparing ⁶⁸Ga-RGD uptake with 18FDG PET study in the same patient.

Results: Full scale automated synthesis of ⁶⁸Ga-RGD dimer was done with more than 70 % product yield using acetate buffer (1.0M) of pH 4.0, at 95^oC heating for 400 sec. More than 60 % injected activity in rat was excreted in 1 hr which is correlating with the reported study. In vivo administration of ⁶⁸Ga-RGD in a patient with carcinoma thyroid revealed avid uptake in multiple metastatic skeletal lesions with associated soft tissue component (right scapular lesions, right sided second rib, vertebrae, sternum, and bilateral iliac bones) correlating with FDG PET/CT findings.

Conclusion: The physicochemical and other quality control data was found in compliance with the standard guidelines of the ⁶⁸Ga-based preparations. ⁶⁸Ga-RGD showed good avidity in the patient with thyroid carcinoma and thus, can be used for tumor imaging. However, further studies with larger number of patients are required to substantiate our findings.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Endo 5: Efficacy of radioiodine therapy plus low dose lenvatinib in advanced metastatic differentiated thyroid cancer: A randomised controlled trial

S Chandra Teja Reddy ¹, S Swayamjeet ¹, Madhavi Tripathi ¹, Ranjit K Sahoo ¹, Chandrasekhar Bal ¹

Introduction: Distant metastases are the leading cause of death in differentiated thyroid carcinoma (DTC). In these patients, Radioactive Iodine-131 (RAI) is the main line of management. Lenvatinib is an FDA approved oral multi-kinase inhibitor that targets VEGF receptors 1–3, FGFR 1–4, RET, c-KIT and PDGFRα to reduce the tumor burden in RAI refractory DTC. This study aims to evaluate efficacy of RAI therapy plus low dose lenvatinib (10mg/day) in RAI-avid advanced metastatic DTC.

Materials and Methods: This is an open-label randomized controlled trial, planned to recruit 50 patients with RAI-avid advanced metastatic DTC on a pilot basis. Block randomisation is done to randomly assign these patients to receive RAI therapy plus lenvatinib (Group A) and standard RAI therapy alone (Group B). Patients with oligometastatic (<5) bone disease and subcentimetric lung nodules were excluded. Primary objective of this study is objective response rate (ORR) and secondary objectives are progression free survival (PFS), overall survival (OS) and safety. This trial is registered with Clinical Trials Registry-India (CTRI/2021/04/032488).

Results: Total 47 patients (2 excluded) are recruited so far in this study (49.1 ± 12.6, range 21-67; 35 females) with 22 and 23 patients randomized into group A & B, respectively. Of these, 24 (53.3%) patients had PTC and 21 (46.7%) had FTC with metastases in lungs (71.1%), bones (71.1%), kidneys (8.9%), adrenals (6.7%), liver (4.4%) and one patient each with brain, ovary and choroid metastases. Baseline parameters are seen to be comparable between two arms. 32 patients (15 and 17 in groups A and B, respectively) completed minimum 6 months follow-up with mean follow-up duration of 282.0 ± 99.9 days. ORR is 60% (95% CI, 32.3%-83.7%) in group A vs 23.5% (95% CI, 6.8%-49.9%) in group B (p value 0.07). Disease progression is seen in 1 and 3 patients of group A and B, respectively. Two deaths are observed one in each group. Median PFS and OS are not yet attained. Grade 3 adverse events are noted in 8/15 (53.3%) patients in group A and 1/17 (5.9%) in group B (p value – 0.004). Hypertension (62.5%) and hand foot syndrome (37.5%) constitute majority of Grade 3 adverse events in group A.

Conclusion: Early results show RAI therapy plus lenvatinib, as compared with standard RAI therapy, is associated with improved objective response rate among patients with RAI avid advanced metastatic DTC. Adverse events were consistent with the known safety profile of lenvatinib, which can be efficiently managed. Further follow-up and studies with bigger sample size are needed to see whether this improvement in ORR translates into improvement in PFS and OS or not.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Endo 6: Clinical outcome of patients with differentiated thyroid cancer and raised antithyroglobulin antibody levels: A retrospective study

Kanishk Markam ¹, Manish Ora ¹, Aftab Hasan Nazar ¹, Sukanta Barai ¹, Amitabh Arya ¹, Prasanta Kumar Pradhan ¹, Sanjay Gambhir ¹

Introduction: Thyroglobulin (Tg) is a tumour marker seen in differentiated thyroid carcinoma (DTC). It becomes unreliable in the presence of an antithyroglobulin antibody (TgAb). The purpose of the study was to examine the long-term results of DTC patients with increased TgAb levels.

Methods: In a retrospective investigation, we included patients with DTC who had elevated TgAb levels after complete thyroidectomy. Patients with persistently elevated Tg (1 ng/ml) or radioiodine avid disease were omitted. Serial TgAb levels, excellent response (ER), incomplete response (IR), and anatomical recurrence were evaluated.

Results: The study involved 76 patients in total. Patients with IR had higher baseline TgAb (1071.27 ± 1216.17 vs. 99.61 ± 91.29 IU/ml, p< 0.001) and central compartment lymph node metastases (70.8% vs.46.4%, p= 0.035) in comparison to those in the ER group. In the first follow-up, 64 (84.2%) patients had a stable or fall in the TgAb (0 to−98.3%). Sixty-eight patients received high-dose radioiodine therapy (RIT). Out of these, 59 (86.5%) had transient, and 51 (75%) had a long-term fall in TgAb. After a follow-up period of 58.74 ± 26.26 months, 63.2% (48 out of 76) patients had IR. Nine (11.8%) patients had a rising TgAb level (3.7–170.9%) from baseline. Eleven patients had 18F-FDG PET/CT scans, and five had metabolically active recurrent disease. Three individuals had cervical lymph nodes removed. During the study, no patients died.

Conclusion: High post-operative TgAb levels and lymph node metastases in the central compartment are risk factors for IR. In these patients, RIT causes a considerable decrease in TgAb. A low level of elevated TgAb is associated with a favourable outcome. Patients with recurrences had very high baseline TgAb >1000 IU/ml. Increased TgAb was not linked to higher mortality rates, but rather with positive clinical outcomes.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Endo 7: Factors predicting the risk of biochemical incomplete response in well-differentiated thyroid cancer after total thyroidectomy

Kanishk Markam ¹, Manish Ora ¹, Aftab Hasan Nazar ¹, Sukanta Barai ¹, Amitabh Arya ¹, Prasanta Kumar Pradhan ¹, Sanjay Gambhir ¹

Introduction: Thyroid cancer (DTC) is the most prevalent endocrine malignancy with a favourable prognosis. However, morbidity is caused by persistent or recurrent disease (P/R disease) and incomplete biochemical response (BIR). In some cases, histopathology and TNM stage may not predict P/R illness and BIR. P/R disease has been predicted using a variety of clinical indicators, histological characteristics, and preablative-stimulated thyroglobulin (presTg). However, the presTg cut-off and diagnostic accuracy are both unclear. The goal of the study was to predict the BIR before radioiodine ablation employing clinical, histological, and biochemical data.

Methods: A retrospective, single-center study, including DTC patients, was done. Demography and factors predicting BIR evaluated.

Results: In comparison to the patients in remission, patients with BIR were older (P = 0.042), had higher presTg (P < 0.001), and lymph nodes (LN) metastases [central or lateral compartment (P < 0.001)]. Visualization of LN on whole-body scan (P = 0.014), higher TNM stage (P = 0.001) and distance metastasis (P < 0.001) were also associated with BIR. On multivariate analysis, high presTg (P < 0.001) and LN metastases (LNscan and histopathologically proven LN involvement, P < 0.001) were associated with BIR. A presTg level ≥12.30 ng/ml has high sensitivity (90.6%) and specificity (80.6%) to predict the BIR (odds ratio 39.90).

Conclusions: PresTg and LN involvement are strong predictors of BIR. A high presTg level combined with LN metastases and non-visualization of the LN on the whole-body scan is alarming for the future BIR. We propose that elevated presTg also be included as a high-risk factor in DTC.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Endo 8: To compare clinical outcome of Graves' disease patients undergoing low dose iodine treatment based on fixed dose versus calculated dose methods

Mehak ¹, Sanjiv Kumar ¹, Yasmeen Atwal ¹, Bhavay Sonik ¹, Chaitanya Tapasvi ¹

Introduction: Despite the long experience of treatment with radioiodine for Graves' disease, controversy remains regarding the optimal radiation method to determine the activity that is required to give adequate radiation dose to the thyroid gland. Two methods to treat Graves' disease with radioiodine (¹³¹1) are the fixed dose activity method and dosimetric calculation method. A prospective study was performed in our department to compare clinical outcome of these two methods.

Materials and Methods: Patients with diagnosed Graves' disease during the study period were divided into two groups on basis of convenient sampling method as: Fixed dose group and Calculated dose group. All patients underwent biochemical and clinical evaluation. The formula of Brunn and co-workers was applied for ultrasonographic estimation of thyroid volume. (The thyroid weight was calculated with the assumption that 1 ml thyroid volume corresponds to 1 gram of thyroid mass). Patients were given 259-370 kBq (710 uCi) of ¹³¹I for RAIU value. 2 Hrs and 24 Hrs radioiodine (¹³¹1) uptake (RAIU) was calculated using thyroid uptake probe (Make Capinetic Model Captus 3000) and Lucite thyroid phantom. Calculated dose group patients were given I-131 as per the following for calculation: Calculated dose = [7400 kBq/g × estimated thyroid wt. (g) x 10^-3] ÷ 24 hrs RAIU. Fixed dose group patients were administered 370-555MBq (10-15 mCi) of ¹³¹1. Assessment of response to radioiodine therapy was based on improvement in sign & symptoms and biochemical evaluation at the end of 2 and 4 months.

Results: 34 patients were included in the study with 17 patients in each group. Males: Females ratio is 11:23 with mean age of all the patients included in the study was 40.91 (SD±12.39) years with median of 41.5 years (range 22-66 years).30/34 patients had received antithyroid drug before radioiodine therapy. In fixed dose group at two month follow-up: mild, moderate and marked improvement was noted in 2, 4 and 11 patients respectively. Similarly, in Calculated dose group at 2 month follow-up 3, 3 and 11 patients showed mild, moderate and marked improvement. Complete 4 month data is still being complied.

Conclusion: No statistically significant difference was observed in initial evaluations of two methods at 2 months follow-up.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Endo 9: Development of thyroid uptake calculation software using deep learning algorithm

Abhishek Kumar ¹, Sushama Awasare ¹, K Biju ¹, N S Baghel ¹, A K Tyagi ¹

Introduction: Nuclear Medicine imaging modality is one of the tools to provide functional information of specific organ of the patients. Qualitative and quantitative information for thyroid functional assessment is carried out using this tool for thyroid management. Imaging data can be used by Machine Learning algorithms like Deep Learning (DL), which are evolving rapidly with a great success rate and in a very broad spectrum of applications. These DL models use Neural Engines and Neural Networks to identify the data representations based on mathematics and algorithms which is called threshold logic. The objective of this study is to apply a practical frame-work of the automated detection of Region of Interest (ROI) in the image for thyroid uptake calculation.

Materials and Methods: Total 36 patients, referred for the thyroid uptake and scan study, were included in this study. The patients were administered 0.925 MBq (25 μCi) 131 I Capsule orally for thyroid scan. The data was transferred in Digital Imaging and Communications in Medicine (DICOM) format from Gamma Camera SPECT system to window based PC. Uptake was calculated using Thyroid Uptake probe and gamma camera at 2 hrs and 24 hrs. However, 24 hrs. uptake data was used for analysis in this study. An artificial intelligence (AI) algorithm is used for automated ROI detection and “Doughnut Background subtraction” on processed DICOM images obtained from the Gamma camera fitted with medium energy all purpose (MEAP) collimator. The uptake measurement obtained by these two methods were compared. The methodology involved in the ROI detection were alpha and gamma channel adjustments and then using canny edge detection which is further passed to an ML (Machine Learning) model to adjust the shape of the ROI according to the specific organ to remove possible radiations coming from nearby organs. The ML model is continuously trained over the dataset from each patient and continues to improve its accuracy.

Results: Comparison was done between uptake values obtained with probe system and with the values obtained using DL algorithm on processed DICOM images of the patient. It is found that the correlation coefficient values were lying in the range of 0.946-0.996. Accurate ROIs were drawn successfully with the help of developed algorithm.

Conclusion: The developed algorithm for calculation of thyroid uptake is very accurate and reproducible. This is fully automated technique in which inter-operator and the inter-facility variability of ROI setting is completely eliminated. This is a robust technique which is user friendly and will be very useful for uptake calculation, which provides quantitative information of thyroid organ.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Category: Hepatology: Hepato 1: Safety profile assessment of ¹⁸⁸Re-N-DEDC lipiodol trans-arterial radionuclide therapy for treatment of hepatocellular carcinoma

Naresh Kumar ¹, Shamim Ahmed Shamim ¹, Priyanka Gupta ¹, G Shivanand ¹, Shalimar ², C S Bal ¹

Introduction: Literatures suggest Trans-arterial radio-embolization (TARE) as promising treatment option for inoperable HCC patients with multifocal lesions and malignant portal vein thrombosis (PVT). These patients have poorer prognosis with limited treatment options. BCLC suggested Trans-arterial Chemo-embolization (TACE) as a recommended therapy in BCLC-B patients. However, it has post-treatment complications such as Nausea, vomiting, pain and fever in ~ 90% of patients. Access site hematoma (~2%) and post-embolization variceal bleed were also some complication seen previously with TACE. The present study aimed to assess the safety profile and management of complications with post-treatment ¹⁸⁸Re-N-DEDC-lipiodol TART in advanced HCC patients.

Materials and Methods: Radiologically and biochemically confirmed HCC patients with/without PVT having ECOG performance status ≤2 and Child Pugh score A /B were recruited for ¹⁸⁸Re-lipiodol TART. The therapeutic activity of ¹⁸⁸Re-N-DEDC lipiodol were injected transarterially under fluoroscopic guidance through femoral branch in super-selective artery of tumor. The patients were admitted in ward for atleast 3 days to assess post-treatment complications. Initially follow-up was done at 2 weeks to assess any change in routine investigation (CBC, LFT, KFT and PT/INR) from baseline. Further, the follow-up was done at 2 months to assess the therapy response. The clinical & biochemical toxicities were graded by CTCAE v5.0.

Results: Thirty-One (31) patients (27 male; 4 female) with mean age 55.9 ± 9.78 years have been recruited for therapy. Overall mean injected activity of ¹⁸⁸Re-N-DEDC lipiodol was 2.9±0.9GBq (78.4±24.2mCi). The radiological and biochemical response were assessed only in 27/31 patients by mRECIST criteria and serum AFP tumor marker level respectively. The disease control rate was seen in 20/27 (~74%) and 14/21 patients (~67%) with radiological and biochemical assessments, respectively. All 31 patients were available for toxicity evaluation, the median follow-up time was of 6 months (range 3-12 months). The post-therapy clinical toxicities (Nausea, Vomiting, Fever, abdominal pain) were observed in 10/31 patients (~32%) of the patients for 2-3 days and were treated symptomatically. One patient showed grade 3 liver toxicity & progressive worsening of LFT, 20 patients showed grade 1 derangements in liver enzymes & 6 patients showed grade 2 derangements in liver enzymes and later on toxicity was managed conservatively in hospital lasting for 3 days. Haematological toxicities were seen in 4 patients (≤Grade 2 in 2 patients & grade 3 in two patients). The patient with grade 3 haematological toxicity had either low haemoglobin or low platelet counts at baseline as well as follow-up and required RBC transfusion or fresh frozen plasma infusion post therapy, respectively. None of the patient had any pulmonary toxicity which were quantitatively seen by comparing baseline and follow-up pulmonary function test. None of the patient had myelosuppression or any other long term toxicity.

Conclusion: Trans-arterial ¹⁸⁸Re-N-DEDC lipiodol therapy proved to be safe and effective with very few complication in advanced HCC patients.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Hepato 2: Role of 18F FDG PET/CT in patients with hemophagocytic lymphohistiocytosis

Rashi Goel ¹, Kunal Chandekar ¹, Nishikant A Damle ¹, C S Bal ¹, Madhavi Tripathi ¹, Rakesh Kumar ¹, Khangembam Bangkim Chandra ¹, S A Shamim ¹, Praveen Kumar ¹, Simran Kalra ¹, Nivedita Kundu ¹

Introduction: Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening, multi-organ disorder caused by immune system dysregulation and characterized by fever, hepatosplenomegaly, cytopenias, and progressive multiple-organ failure. HLH is often secondary to autoimmune diseases, cancer (most commonly lymphoid cancers and leukemias), or infections in contrast to familial HLH. This study aims to evaluate the role of ¹⁸F FDG PET/CT in patients with a clinical suspicion of HLH.

Materials and Methods: We retrospectively reviewed data of 11 patients (2 female, 9 male; age 4–52 years) with a clinical suspicion of HLH by HLH-2004 criteria referred from the medicine department of our tertiary care hospital between January 2018 to June 2022. All patients underwent ¹⁸F-FDG PET/CT to identify the possible trigger for HLH and were correlated with histopathology.

Results: 9 (81.8%) patients were found to have anemia, 10 (90.9%) had thrombocytopenia, 6 (54.5%) had hypertriglyceridemia. Elevated levels of ferritin were found in 9 (81.8%) patients. On PET/CT images, splenomegaly was found in 5 (45.4%) patients, out of which 4 (80%) had diffusely increased FDG uptake and 1 (20%) showed focal splenic lesions. Hepatomegaly was observed in 4 (36.4%) patients. Diffuse bone marrow uptake in the axial and appendicular skeleton was seen in 4 (36.4%) patients and 2 (18.2%) patients showed focal increased FDG uptake in marrow. Lymphadenopathy with increased FDG uptake was seen in 7 (63.6%) patients and all had involvement of 2 or more nodal groups. Based on scan findings suspicious for lymphoma/leukemia, histopathological correlation was advised for 8 (72.7%) patients. Of these, histopathological reports of 5 (62.5%) patients were positive for malignancy [HL:3 (60%), Leukemia:1 (20%), B cell lymphoma:1 (20%)] whereas histopathological reports of 3 (37.5%) patients did not reveal any malignancy. PET/CT images of 3 (27.2%) patients did not reveal any findings suggestive of underlying malignancy.

Conclusion: ¹⁸F FDG PET/CT was able to correctly detect haematolymphoid malignancy in 5/11 (45.4%) patients and accurately rule it out in 3/11 (27.3%) patients, thereby benefitting 8/11 (72.7%) patients with clinical suspicion of HLH. Thus, it is helpful for identifying the possible trigger (particularly malignant disease), extent of disease in secondary HLH and aids in guiding site for biopsy. However, more studies on a larger patient population are required to validate the same.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Hepato 3: Comparison of clinical response of ¹⁸⁸Re-N-DEDC lipiodol and ⁹⁰Y-SIRsphere for treatment of Inoperable hepatocellular carcinoma

Shamim Ahmed Shamim ¹, Naresh Kumar ¹, G Shivanand ¹, Shalimar ², C S Bal ¹

Introduction: FDA approved ⁹⁰Y-microspheres [TheraSpheres and SIRspheres] TARE have been recommended treatment of intermediate stage (BCLC B) HCC who are not good candidates for TACE due to multiple bulky tumors and advanced stage (BCLC C) with solitary lesion and segmental or lobar PVT. ¹⁸⁸Re-N-DEDC lipiodol is an emerging TART agent due to its comparable β-energy (E_βmax 2.1 MeV) and penetration range (~11mm) of ¹⁸⁸Re to ⁹⁰Y. Indigenously developed TART agent DEDC (Diethyl-dithiocarbamato) by BARC, Mumbai, labelled with ¹⁸⁸Re in lipiodol phase has advantage of simple and on-site labelling procedure, cost-effectiveness and least radiation induced side effects. Present study aimed to compare the clinical response of ¹⁸⁸Re-N-DEDC lipiodol and ⁹⁰Y-SIRsphere for treatment of intermediate and/or advanced HCC.

Materials and Methods: Radiologically and biochemically confirmed HCC patients with/without PVT having ECOG performance status ≤2 and Child Pugh score A /B were recruited. Baseline serum alpha-fetoprotein (AFP) was obtained for biochemical correlation and follow-up. Total 14 patients, 7 in each groups, had comparable lesion size were recruited for this study. Pre-therapy dosimetry was performed by patient-specific partition model for ⁹⁰Y-SIRsphere, while empirical activity recommended by IAEA were injected trans-arterially for ¹⁸⁸Re-N-DEDC lipiodol. Response was assessed at 2 months post-therapy by mRECIST criteria and S. AFP level. Further, follow-up was performed at every 3 months to know disease status.

Results: Fourteen (14) patients (13 male; 1 female); 7 patients in each ¹⁸⁸Re-N-DEDC lipiodol and ⁹⁰Y-SIRsphere groups, with mean age 56.2 ± 12.45 years have been recruited for this study. Overall mean injected activity was 3.26±1.7GBq for ⁹⁰Y-SIRsphere group, and 3.29±1.16GBq for ¹⁸⁸Re-N-DEDC lipiodol group. The median follow-up period was of 6 months. Radiologically, in ⁹⁰Y-SIRsphere group, 2 patients had complete or nearly complete response, 4 patients had partial response and 1 had disease progression; while in ¹⁸⁸Re-N-DEDC group, 2 patients had complete response, 3 had partial response; 1 had stable disease and 1 had disease progression. Biochemically, 3 patients (1 in ⁹⁰Y-SIRsphere group and 2 in N-DEDC group) had non-AFP producing tumor. Thus, of 6 patients in ⁹⁰Y-SIRsphere group, 2 had complete response and 4 showed partial response, while in N-DEDC group, of 5 patients, 1 had complete response, 3 had partial response and 1 showed disease progression.

Conclusion: TARE with ⁹⁰Y-SIRsphere and ¹⁸⁸Re-N-DEDC lipiodol shows almost similar response in intermediate/advanced HCC patients. Thus, indigenously developed DEDC kits labelled with ¹⁸⁸Re-lipiodol can be used as a viable economic TARE agent for HCC treatment.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Hepato 4: Assessment of prognostic value of metabolic imaging biomarkers as established by baseline pretreatment 18F-FDG PET/CT in patients with hepatocellular carcinoma

Meghana Prabhu ¹, G K Chaitanya ¹, Ashok Choudhury ², Fahad Nisamudeen ², Vanjul Kansotia ², Hanuman Prasad Yadav ²

Introduction: FDG PET/CT is not routinely used for the diagnosis and staging of HCC due to low tracer uptake. This study aimed to assess the prognostic value of performing a baseline PET/CT with FDG in patients with HCC who were eventually treated.

Methods: 77 patients pathologically or radiologically confirmed HCC underwent baseline pre-treatment 18F-FDG PET/CT. Spearman correlation was performed between SUVmax & AFP levels and between SUVmax & tumor size. Mann-Whitney U test was applied to see if there is any difference in SUVmax and tumor size between HCC patients with and without extra hepatic metastases.

Results: Patient characteristics are listed in Table 1. Median tumor SUVmax was 4.5 (range: 1.7-13.1). Weak correlation was found between SUVmax and AFP levels which is not statistically significant (rho-0.225, p=0.05). Moderate positive correlation was found between SUVmax and the tumor size which is statistically significant (rho- 0.428, p = 0.0001). There is significant difference in SUVmax (p=0.0002) and in tumor size (p= 0.001) between HCC patients with extrahepatic metastases and no extra hepatic metastases. HCC patients with extra hepatic metastases showed higher SUVmax (5.9 v/s 3.3) and a larger tumor size (9.9cm v/s 6.4 cm). Extrahepatic metastases were seen in 66.6% of the patients with tumor size >5 cm. Portal vein tumor thrombus was found in 61% of our patients with median SUVmax of PVTT 3.1.

Table 1.

Details of antibody, magnetic resonance imaging and positron emission tomography of the entire group 9 (n=52)

	PET +ve	MRI +ve	PET+/MRI−ve	PET−/MRI +ve	CSF +ve (25)*	EEG +ve (28)^#
Antibody positive=23	23 (100)	10 (43.4)	13 (52.1)	0	3 (14.2)	9 (39.1)
Antibody negative=29	22 (75.8)	12 (41.3)	10 (34.4)	0	2 (6.8)	7 (24.1)

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*CSF available in 25 patients, ^#EEG available in 28 patients. MRI: Magnetic resonance imaging, PET: Positron emission tomography, EEG: Electroencephalogram, CSF: Cerebrospinal fluid

Conclusion: SUVmax measured in 18F-FDGPET/CT scans performed in patients with HCC at the time of diagnoses is an important prognostic factor. Higher SUVmax seem to significantly correlate with higher incidence of extrahepatic metastatic disease. Contrast enhanced18F-FDG PET/CT is a useful investigation in primary staging of HCC to detect extrahepatic metastases, with better results in tumor size >5 cm and SUVmax >4.5. These results must be confirmed by larger number of patients.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Category: Infection and Inflammation: Infection 1: The role of FDG PET/CT in necrotizing fasciitis – Challenging and rare clinical condition

P Verma ¹, P Shinde ¹, R V Asopa ¹

Introduction: Necrotizing fasciitis is a rapidly progressive infection of the deep soft tissue with a high mortality rate. Establishing the diagnosis is challenging and requires a high index of clinical suspicion. Patients may present with signs and symptoms of sepsis, including high fever, hypotension, and multiorgan failure. The main clinical challenge is distinguishing superficial from deep soft-tissue involvement.

Materials and Methods: This was a retrospective analysis of 4 patients (4 males; age range 38-64 years; mean age 50.25 years) presenting with pain, fever and soft tissue inflammatory signs on clinical examination in a specific region with a differential diagnosis of osteomyelitis, cellulitis and necrotizing fasciitis. They were referred for 18F-FDG PET/CT scan to evaluate the site of infection and well as to look for any occult sites of infection in the rest of the body. 18F-FDG PET/CT findings were compared to the clinical examination findings and follow up. The patients were given the diagnosis of necrotizing fasciitis based on clinical and imaging findings. They were managed conservatively with antibiotics according to culture sensitivity evaluation, daily dressing and followed up regularly.

Results: FDG PET/CT of 4 patients revealed 9 lesions in total (2 lesions per patient for 3 patients and 3 lesions in the 4^th patient). Two of these were not seen in initial clinical evaluation and were closely followed up. The lesions showed FDG uptake with mean SUV max 5.1 (range 1.51-7.77) and involved soft tissue in intermuscular and intramuscular planes with air foci and surrounding fat stranding and extending to overlying skin.

Conclusion: Necrotizing fasciitis is a rare life threatening disease that requires immediate attention. Due to the vague presentation and rarity of the condition, it may go undiagnosed in early stages. The differential diagnosis is cellulitis, osteomyelitis or any other local inflammatory pathology. FDG PETCT imaging can be used to enhance the sensitivity and specificity for the diagnosis of Necrotising fasciitis. FDG PET CT allows whole body scan and so it is possible to detect lesions in other areas and evaluate them. It may also potentially be used for treatment response in these patients.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Infection 2: Role of gallium 68 citrate PET CT in the evaluation of spinal tuberculosis – A case series

S S Sunny ¹, J Hephzibah ¹, V Krishnan ¹, Abi Manesh ²

Introduction: Skeletal involvement is noted in 10% of Extra-pulmonary TB (Tuberculosis), of which half present as spinal tuberculosis (STB). Early detection and treatment is of paramount importance to prevent deformities and neurological deficits. Conventional imaging techniques like X- rays or CT rely on anatomical changes and have limited detection in early stages. The persistence of symptoms after ATT (anti-tubercular therapy) may cause a dilemma to clinicians on the decision of its continuation/ cessation and MRI spine may be non-contributory in such cases to identify active disease. The novel tracer, Gallium68 Citrate is found to localise in infection as it binds to ferritin in leucocytes and bacteria and lactoferrin in the neutrophils. This study aimed at studying the utility of Gallium68 Citrate PET CT imaging modality in STB.

Materials and Methods: This case series was a prospective study carried out from February 2022 to September 2022. Those patients with proven spinal TB (based on microbiological/ histopathological/ X-pert gene analysis) presenting to Infectious diseases or Spine surgery OPD who were treatment naïve or received ATT for less than or equal to 2 months duration were included in the study. All the patients underwent a Gallium 68 citrate PET CT with Siemens BIOGRAPH - 6 (LSO-crystal /6-slice) PET-CT scanner. Trans-axial, coronal and sagittal PET images were reviewed concurrently with fused PET/contrast CT images. CT with contrast (Omnipaque-80ml) followed by PET scan for area of interest was done 30 minutes to 1-hour following intravenous administration of a dose of 3-5 mCi of 68Ga citrate. The clinical details, presence of uptake of the tracer (more than tracer activity in the Aorta), corresponding CT findings were recorded. This was correlated with MRI spine if available.

Results: Of a total of 28 patients who underwent Ga68 citrate PET CT, 11 patients were included in the study. There were 4 male and 7 female patients, age ranging from 26 to 64 years (average 46 years). The most common symptom was back pain and biochemical parameters such as ESR and CRP at baseline were elevated in all patients. The scan was done before the initiation of ATT in 3 patients, after 1 week of ATT in 5 patients and after 1-2 months of ATT in 3 patients. Avidity of the diseased area was noted in 6 of the patients. Absence of uptake was noted in the other 5 patients who had either presence of necrosis, abscesses or erosions/ lysis of the vertebral body or discs. Only 2 patients had a follow up scan after 9 months of ATT and the repeat scans showed resolution of uptake correlating with the good treatment response clinically.

Conclusion: Gallium 68 citrate PET CT is a useful modality in STB to demonstrate disease activity. In the presence of necrosis/ abscesses/ erosions of vertebrae, where cellular content is reduced, the disease appears non-avid. However it can be used as a potential marker to demonstrate treatment response in those patients with uptake on baseline scan and in guiding decisions of continuation/ cessation of ATT.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Infection 3: Role of 18F-FDG PET in guiding management of skull base osteomyelitis – A single institutional retrospective study

Awiral Saxena ¹, P Shanmuga Sundaram ¹, Padma S Sundaram ¹

Introduction: Skull base osteomyelitis is a clinically challenging disease to treat and decision to stop the treatment is based on multiple clinical, lab & imaging parameters. 18F-FDG PET is a sensitive tool to aid in assessment of treatment response and along with other clinical & lab parameters guides in assessment of resolution of disease. Clinical markers ESR and CRP are non-specific for inflammation and can be raised in comorbid patients without active disease. Hybrid 18F-FDG PET (along with CT or MRI) gives a comprehensive overview of disease activity, sites of involvement, subtle progression (with or without anatomical change) and is a guide for biopsy site for appropriate tissue culture. We aimed to asses relation between clinical parameters & 18F-FDG PET findings and impact of 18F-FDG PET on clinical management. Patients with at least a baseline & follow up PET scan were taken and parameters like SUV Max, CRP and ESR were analysed.

Materials and Methods: 33 patients (January 2015 – June 2022, M: F=30:3, Mean age 68.8 ± 7.3 years, 50-84 years) were included who had at least a baseline and a follow up 18F-FDG PET (Mean follow up: 7.5 months). Parameters like SUV Max, ESR & CRP (Initial, follow up, percentage change) were analysed and outcomes based on 18F-FDG PET reports were classified into Resolution (1), Partial response (2), progression (3) and stable disease (4). The clinical course and response on anatomical imaging was also compared with 18F-FDG PET.

Results: There was moderate correlation between Initial SUV and ESR (34%) and Follow up SUV and CRP (58%) values. Percentage change in SUV Max showed a moderate correlation with both percentage change in ESR & CRP (37 & 35%). Mean Percentage change in SUV Max was 70% (1), 35% (2), ℒ40% (3) and ℒ18% (4) respectively. 48% (16/33) patients had clear cut management change with 18F-FDG PET (resolution, progression, stable disease) with either escalation or stopping of antibiotics/antifungals. The most important group clinically was the partial response group (52%, 17/33 patients), which was analysed along with other clinical parameters and decision to either stop the treatment or continue further was taken. On retrospective analysis the group in which treatment was continued (8 patients) had 20 (± 14) % change, whereas the group which was only monitored further (9 patients) had 48 (±10) % change.

Conclusion: 18F-FDG PET showed a moderate correlation with clinical markers used in follow up of patients with skull base osteomyelitis and is a reliable investigation for assessment of disease status. This can be used as a guide along with clinical evaluation for de-escalation of treatment.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Infection 4: Pitfalls in ^99mTc-ethambutol scintigraphy in imaging patients with tuberculosis – What we should know

Adiba Ghazal ¹, Arup Roy ¹, Nishikant Damle ¹, Varsha Tiwari ¹, Praveen Kumar ¹, Piyush Ranjan ¹, Bisakh Bhattacharya ¹, Sunit Sikdar ¹, Vikrant Manhas ², Manisha Jana ³, Chandrasekhar Bal ¹, Madhavi Tripathi ¹

Introduction: Initial studies with ^99mTc labeled Ethambutol have shown promising results. However, being a new modality, none of the published literature describe the exact limitations and false results which are essential for accurate diagnosis and patient management. Therefore, in this study we aimed at identifying false positive and false negative cases that can be seen with ^99mTc-Ethambutol scintigraphy.

Materials and Methods: We retrospectively reviewed results of 81 patients out of which 10 were suspicious for and 71 had confirmed tubercular infection at atleast one site. Scans were reported positive if tracer uptake was seen outside the physiological sites of distribution. Microbiologic and /or Histopathological reports were considered as the gold standard.

Results: ^99mTc labeled Ethambutol scintigraphy showed false positive uptake in 3 patients who had:

IgG4-related disease in an orbital lesion
Brain metastasis from lung carcinoma
Myxoid fibroma of the abdominal wall.

False negative result was seen due to the following reasons:

Nodal lesions less than 1.5 cm in size (for planar imaging)
Lesions showing extensive necrosis
Abdominal lesions masked by bowel activity (planar imaging)
Mediastinal blood pool activity masking lesions in its vicinity on planar imaging (sternal/chest wall lesions)
Liver granuloma uptake indiscernible from the physiological liver uptake.

SPECT/CT was found to be useful in few of the above described lesions which were false negative on planar imaging.

Conclusion: There are certain pitfalls in Ethambutol scintigraphy and these should be known before interpreting the scans so as to avoid false results.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Infection 5: Incremental value of ¹⁸F-FDG PET/CT over ^99mTc-MDP bone scan in infection versus aseptic prosthesis loosening

Hemant Khairwa ¹, Sambit Sagar ¹, Dikhra Khan ¹, K V Sivasankar ¹, Anushna S Babu ¹, Mohammad Umar ¹, Abhishek Gawande ¹, Shamim Ahmed Shamim ¹, Rakesh Kumar ¹, C S Bal ¹

Introduction: 99mTc-MDP (Methylene diphosphonate) bone scan plays an important role in differentiating infection and aseptic loosening of prosthesis. However, in patients who have already received empirical course of antibiotics, the MDP uptake might persist for long time making it difficult to differentiate between infection and aseptic loosening. The main aim of our study was to evaluate the additive role of ¹⁸F-FDG-PET/CT (Flurodeoxyglucose) over 99mTc-MDP bone scan to differentiate between infection and aseptic loosening in patients presenting with prosthesis related symptoms.

Methods: This is a retrospective study conducted at a tertiary care centre in India. All patients who were referred to our department with clinical suspicion of infection vs aseptic prosthesis loosening were included in the study during the period (Jan 2019 to Oct 2022). All patient characteristics were retrieved from our patient database. As per our department protocol, all patients underwent 99mTc-MDP planar imaging and SPECT/CT followed by 18F-FDG PET/CT to increase the diagnostic accuracy if the static images findings were equivocal. Patients who didn't undergo either MDP bone scan or ¹⁸F-FDG-PET/CT were excluded. Finally a total of 12 patients were included. Both MDP bone scan or ¹⁸F-FDG-PET/CT were reviewed by two experienced nuclear medicine physicians and the results were compared.

Results: A total of 12 patients were included in the study. The mean age of the patients was 49.71±19.89 years. There were 9 males and 3 females. MDP bone scan was positive in 10 (83.3%) patients. FDG-PET/CT was positive in 5 (38.4%) patients. MDP bone scan was negative in 2 patients which was negative on FDG-PET/CT scan as well. Out of 10 patients with positive bone scan, 5 patients turned out to be negative on FDG PETCT and 5 patients turned out to be positive on 18F-FDG PET/CT. Thus 18F-FDG PET/CT was able to rule out infection in 5/10 (50%) patients and confirmed infection in 5/10 (50%) patients who had positive MDP bone scan.

Conclusion: In patients with negative bone scan there is no need to perform further ¹⁸F-FDG PET/CT which is a relatively costlier modality. However, in patients with positive bone scan, ¹⁸F-FDG PETCT has a promising role as an additional modality in confirming infection and also in excluding patients without infection. Prospective studies with larger sample size is required to confirm our findings.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Infection 6: Establishing the ideal time point for imaging of tubercular lesions using ^99mTc ethambutol scintigraphy and SPECT/CT

Adiba Ghazal ¹, Nishikant Damle ¹, Dikhra Khan ¹, Arup Roy ¹, Varsha Tiwari ¹, Apoorva Tyagi ¹, Geetanjali Arora ¹, Praveen Kumar ¹, Madhavi Tripathi ¹, Chandrasekhar Bal ¹, Vikrant Manhas ¹

Introduction: Ethambutol is a routinely used antitubercular drug. Ethambutol (EMB) when labeled with ^99mTc is specifically taken up by Mycobacterium tuberculosis, and can be imaged using the gamma camera.^99mTc- EMB being a new radiopharmaceutical agent, there is scant literature to suggest the ideal time point for imaging. Therefore we aimed to do sequential scans of patients injected with ^99mTc- EMB to establish this.

Materials and Methods: Seventeen patients were injected with radiolabeled 370 MBq^99mTc-Ethambutol synthesized in-house and serial anterior and posterior whole-body scans were acquired on a dual head SPECT/CT gamma camera with low energy high resolution (LEHR) collimator. The scans were acquired as 5 min dynamic image and static images at 15 min, 30 min, 45 min, 1 hr, 2 hr, 4 hr, 6 hr, 12 hr and 24 hrs (minimum of 4 serial images). All the scans were evaluated by two independent nuclear medicine physicians.

Results: The labeling efficiency of the ^99mTc-Ethambutol was above 95% in all the cases. Studies of 17 adult patients (M=6, F=11) median age of 31 years (Range=19-62 years) with tubercular infection underwent^99mTc-ethambutol scintigraphy for the evaluation of optimal uptake at the disease site at various time points. Out of 17 patients, 12 had extraspinal TB, and showed optimal lesion uptake on 45min and 1 hour static images (70%) post administration of radiopharmaceutical, with common sites of involvement being knee, shoulder, and sternum. While in the remaining 5 cases, 3 had spinal TB, out of which 2 showed optimal lesion uptake at 45 min and 4 hr static images. Two patients had both spinal and extraspinal TB, in which uptake was only seen in extraspinal lesions at 1 hr static images.

Conclusion: The ideal time point for visualization of bone lesions in tuberculosis is 45 ℒ60 minutes after injection of ^99mTc- Ethambutol and a single whole body image (anterior and posterior) at this time point appears sufficient. Delayed or serial frequent imaging appears unnecessary.

Acknowledgement: This study was funded by ICMR, New Delhi.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Infection 7: Clinical utility of F-18 fluorodeoxyglucose PET-CT in human immunodeficiency virus patients

P A Meivel ¹, A Murali ¹, Krishna S Nair ¹, R Narmadha ², R Arulmurugan ³

Introduction: To determine the usefulness of FDG PET-CT in the investigation of serology-positive HIV patients and assess the impact of viremia and anti-retroviral therapy on FDG uptake.

Materials and Methods: A retrospective observational descriptive study was performed in a tertiary care hospital in South India between January 2022 and October 2022. A total of 36 scans were performed on 32 patients for various indications such as suspected opportunistic infections, pyrexia of unknown origin, lymphoma, and malignancy. All the patients underwent whole-body FDG PET-CT in an integrated PET-CT scanner. Scan findings were analyzed qualitatively as well as quantitatively using SUVmax. The images interpreted were correlated with patient demographics, clinical indication, HIV viral load, and antiretroviral therapy status. Based on the data availability, 20 patients were included to analyze the impact of HIV viral load and Anti-retroviral therapy on FDG uptake in the lesions detected.

Results: A total of 32 patients (male = 20, female = 12) underwent PET-CT for the indications below, opportunistic infection (n= 16), PUO (n= 5), lymphoma (n= 5), and solid malignant tumors (n= 6). HIV viral load, Anti-retroviral therapy status, and their impact on FDG uptake were analyzed in 20 patients (male = 15, female = 5; opportunistic infection = 13, PUO = 4, lymphoma = 3). Eleven of twenty patients were on ART and nine were treatment-naive. FDG PET-CT identified lesions directing further management in 16 out of 20 patients. The lesions detected and organs involved include lymph nodes (n= 14), spleen (n= 8), lungs (n= 6), liver (n= 2), brain (n= 1), bone marrow (n= 2), and adrenal gland (n= 1). For analysis, 3 lymphoma patients were excluded to avoid skewness in the FDG uptake. SUVmax of lesions in the ART-naive group (n= 9; median viral load = 77302 copies/ml, median SUVmax lymph nodes = 6.6, median SUVmax spleen = 4) and ART group (n= 8; median viral load = 2591.5 copies/ml, median SUVmax lymph nodes = 5.6, median SUVmax spleen = 4.3). There is a minimal correlation between the HIV viral load and FDG uptake (median SUVmax) in the lymph nodes (Pearson's correlation coefficient r=0.03), spleen (r=0.06), liver (r=-0.1), and lungs (r=0.29). Non-parametric tests (Mann Whitney U) of FDG uptake (median SUVmax) found no relationship between ART status and FDG uptake in lymph nodes (p=0.69), spleen (p=0.28), liver (p=0.40), and lungs (p=0.15).

Conclusion: FDG PET findings helped to identify lesions in more than two-thirds of the patients (approximately 80%) correlating with underlying infection/ inflammation or lymphomatous involvement guiding further management or evaluation. We conclude that HIV viral load and anti-retroviral therapy status do not have a significant influence on the FDG uptake for the indications intended. Further larger prospective studies are warranted to ascertain the same.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Infection 8: Comparison of ⁶⁸Ga-NOTA-ubiquicidin PET and ^99mTc-ubiquicidin scintigraphy as infection imaging techniques

Satya Dev Maurya ¹, Nishikant Avinash Damle ¹, Dikhra Khan ¹, Sanjana Ballal ¹, Chandra Sekhar Bal ¹, Varsha Tiwari ¹, Sumit Garg ¹, Sambit Sagar ¹, Praveen Kumar ¹, Rakesh Kumar ¹, Mohammed Tahir Ansari ¹, Venkatesan Sampath Kumar ¹, Vijay Kumar ¹

Introduction: Ubiquicidin is an antimicrobial peptide with great potential for imaging of infectious diseases. Ubiquicidin (UBI) can be labelled with ^99mTc and also ⁶⁸Ga, with NOTA acting as a bifunctional chelator for the latter. We hereby aim to compare the labeling technique, biodistribution, efficacy, and cost-effectiveness of ⁶⁸Ga-NOTA-UBI PET/CT and ^99mTc-UBI Scintigraphy for an overall assessment of the feasibility of these two techniques.

Materials and Methods: For the labelling of UBI with ⁶⁸Ga, NOTA-UBI (29-41) was procured from ABX advanced biochemical compounds (Germany). All other chemicals used were of analytical grade.⁶⁸GaCl₃ was added to the solution of NOTA-UBI and 5 M sodium acetate buffer. The reaction vial was incubated for 15 min at 90°C. After incubation, the preparation was filtered through a C-18 SEP PAK cartridge for purification and then eluted with 70% ethanol. For ^99mTc labeling, UBI (29-41) was procured from ABX advanced biochemical compounds (Germany). UBI was labeled with ^99mTc by a reduction method adapted from the method described by Arjun et al (2016). ^99mTc pertechnetate activity was added to the mixture followed by incubation at room temperature for 20 minutes.

Results: ^99mTc-UBI was successfully labeled with a labeling efficiency of 97.46 ± 1.06 (n=25) in both mobile solvents, namely saline and 5% HCl in methanol. Further, ⁶⁸Ga-NOTA-UBI was also successfully labeled with a labeling efficiency of 98.25% ± 1.32% (n=4) in sodium citrate as mobile solvents. UBI labeled with ⁶⁸Ga and ^99mTc always had a clear and colorless solution with pH of 5 and 6 respectively. In the labeling of ^99mTc-UBI, heating was not required but in ⁶⁸Ga-NOTA-UBI heating was required at 90°C for 15 minutes yet the synthesis of ⁶⁸Ga-NOTA-UBI took a lesser time (18.15 ±1.3 min.) than the synthesis of ^99mTc-UBI (29.36±3.84 min.).^99mTc-UBI and ⁶⁸Ga-NOTA-UBI showed similar biodistribution in patients with suspected periprosthetic infection and satisfactory target to non target ratio in true positive cases. Cost of NOTA-UBI was approximately Rs.90000 per 1mg while that of UBI for ^99mTc labeling was Rs. 94000 per 20mg. ^99mTc-UBI and⁶⁸Ga-NOTA-UBI had similar biodistribution and both were able to depict infection. ^99mTc-UBI requires only a gamma camera setup, and can also be synthesized in house as per requirement, whereas PET/CT facility and ⁶⁸Ge/⁶⁸Ga generator are basic requirements for ⁶⁸Ga-NOTA-UBI imaging.

Conclusion: Overall, comparable labeling efficiency, similar biodistribution, satisfactory positive results and cheap, ready availability makes ^99mTc-UBI scintigraphy a practically useful imaging modality with a good cost to benefit ratio compared to ⁶⁸Ga-NOTA-UBI scintigraphy especially in the setting of limited resources.

Acknowledgement: Study was funded by ITR division, ICMR New Delhi.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Infection 9: Utility of ^99mTc-ubiquicidin scintigraphy in diagnosis of orbital aspergillosis

Shreya ¹, Nishikant Damle ¹, Rachna Meel ¹, Dikhra Khan ¹, Sambit Sagar ¹, Varsha Tiwari ¹, Apoorva Tyagi ¹, Geetanjali Arora ¹, Praveen Kumar ¹, Chandrasekhar Bal ¹, Madhavi Tripathi ¹, Sanjay Sharma ²

Introduction: Aspergillosis is a fungal disease with a wide range of clinical manifestations that poses the greatest risks to immunocompromised patients. The diagnosis of Aspergillosis becomes challenging especially in odd sites like the orbits. Antimicrobial peptides like ubiquicidin show high specificity for bacterial and fungal infections. The present study was conducted to evaluate the feasibility of ^99mTc-Ubiquicidin scintigraphy in the diagnosis of Orbital Aspergillosis.

Materials and Methods: Images of five male patients (mean age = 55.2 years; age range = 32–62 years) with suspected Aspergillosis were reviewed in this retrospective study. Patients were injected with 10mCi of ^99mTc-UBI intravenously. A dynamic image was acquired followed by subsequent static views taken at 15 min, 30 min, 45 min, 1 hour, and 2 hour post-injection. To study the biodistribution, whole-body anterior and posterior images were acquired at 1 hr; SPECT/CT was performed in 4 patients. Scans were interpreted as true positive, false-positive, true negative, or false-negative based on histopathological evaluation, imaging findings (CECT/MRI), and clinical follow-up as the gold standard.

Results: Of the five studies included in the analysis, uptake was seen in 4 patients. 3 were true positive, 1 was false negative, and 1 was true negative for the diagnosis of aspergillosis. Thus, the scan showed sensitivity and specificity for the diagnosis of aspergillosis to be 75 percent and 100 percent, respectively. The study's positive predictive value (PPV) and negative predictive value (NPV) were 100% and 50%, respectively. The overall accuracy of ^99mTc-UBI scintigraphy for attributing infective etiology to the lesions was 80%.

Conclusion: Where there is a high index of suspicion for fungal etiology of orbital lesions, our study suggests that ^99mTc-UBI scintigraphy with SPECT/CT appears to be a promising modality, in attributing infective causality, though larger studies are necessary.

Acknowledgment: The study was funded by ICMR, New Delhi, India.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Infection 10: Impact of target/nontarget ratio in the accurate interpretation of ^99mTc-ubiquicidin scan in suspected implant infection

S Garg ¹, A Khurana ¹, N A Damle ¹, C S Bal ¹, M Tripathi ¹, V Tripathi ¹, A Tyagi ¹, G Arora ¹, S G Ravindra ¹, V Kumar ¹, T Ansari ¹, S Venkatesan ¹

Introduction: The diagnostic differentiation between post-operative orthopaedic infection and sterile inflammation with an implant in situ has always been a grey area. Early diagnosis and timely intervention must be performed as they can substantially affect clinical outcomes. Also, emerging antibiotic resistance has created a demand for novel methodologies for early detection and characterization of infection, which can aid judicious antibiotic use. Here we present a series of 25 patients with suspected implant infection, with an intent to arrive at an objective method of interpreting the scans to achieve satisfactory positive predictive value (PPV). From our initial experience with ^99mTc-Ubiquicidin scintigraphy we felt that it is imperative to establish a cut off value for the tracer uptake in the affected and non-affected regions.

Materials and Methods: 25 antibiotic naïve suspects of implant infection underwent ^99mTc-Ubiquicidin scintigraphy with planar and SPECT/CT imaging acquired at various time points, which were reported as positive/negative for infection. Identical regions of interest were drawn on the affected (implant) site and the contralateral site (control) in the 1-hour whole body images. The ratio of mean counts were calculated between affected site and control site. We compared the diagnostic accuracy of the ^99mTc-Ubiquicidin scan with microbiological results or improvement on antibiotics as reference standards.

Results: The mean age of the patients was 43.12 ± 12.82 and the gender distribution (M/F) was 18/7. Out of the 25 patients, visual interpretation of Ubiquicidin scan showed infection in 24 patients and was negative in 1 patient. The area under the ROC curve (AUROC) for Affected/Non-affected Ratio predicting reference Standardwas 0.693 (95% CI: 0.461 - 0.926). However, there was no statistical significance (p = 0.114). At a cutoff Ratio ≥1.531 for Affected/Non-affected, the sensitivity, specificity and PPV for detection of infection were 67%, 90% and 90.9% respectively.

Conclusion: With a cut off value of 1.531 for the target/non-target ratio we were able to achieve a specificity of 90% and a PPV of 90.9%. Thus, keeping this cut off value has a potential to correctly point out more number of patients who would not benefit from antibiotic therapy.

Acknowledgement: The study was funded by the ITR division ICMR, New Delhi.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Infection 11: Comparison between kit-based and in-house preparation of ^99mTc labeled ubiquicidin

Sonu ¹, Nishikant A Damle ¹, Geetanjali Arora ¹, Apoorva Tyagi ¹, Varsha Tiwari ¹, Chandrasekhar Bal ¹, Madhavi Tripathi ¹, Praveen Kumar ¹, Dikhra Khan ¹, Mohammed Tahir Ansari ¹, Venkatesan Sampath Kumar ¹, Vijay Kumar ¹, Rajeev Kumar ², Hitesh Verma ³, Rachna Meel ⁴

Introduction: ^99mTc labeled Ubiquicidin 29-41 fragment (^99mTc -UBI) is a promising radiopharmaceutical for human infection imaging. Although commercial cold kits are available, to ensure easy and impromptu availability, in house synthesis of this tracer is a pressing need. We aimed to compare numerous parameters while synthesizing this tracer using both methods.

Materials and Methods: Inhouse labeling was performed with Ubiquicidin (29-41) procured from ABX Radeberg, Germany and the technique was based on the reduction method described by Sarda-Mantel et al (2007) and Arjun et al (2016). Freshly prepared stannous chloride in HCl (SnCl2) was added to UBI solution in acetic acid followed by addition of Tc-99m pertechnetate activity. pH was adjusted with sodium hydroxide (NaOH) and mixture was then incubated at room temperature. Kit based method involved the use of commercially available kit (supplied by BRIT, BARC, Mumbai) which is a pre-dispensed sterile formulation to be reconstituted with sterile 99m-Tc sodium pertechnetate solution which is further added to NaOH for pH adjustment followed by incubation at room temperature and saline reconstitution. Labeling efficiency (LE) in both the methods was analyzed by paper chromatography using Silica Gel/ITLC paper as stationary phase, saline and 5% HCl in Methanol as mobile phase. After intravenously injecting ^99mTc-UBI, Dynamic images are acquired followed by serial static (spot) images at designated time intervals in patients with suspected infection.

Results: Both methods were used numerous times and results are tabulated below. After using similar amount of peptide in both the methods, observing comparable radiochemical purity and biodistribution, at the expense of additional 10 minutes of radiosynthesis time, a significant cost reduction has been seen with the in house labeling technique.

Characteristics	Kit based	In house
Cost	5800 Rs. for 2 patients	4740 Rs. for 20 patients
Radiochemical purity (%)	>90	>90
Biodistribution	Normal	Normal
Radiosynthesis time (min)	20	30
Amount of peptide (μg)	50	50

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Conclusion: In-house prepared ^99mTc-UBI seems to be a viable alternative to the kit based method and has the advantage of being highly cost effective with easy, immediate availability.

Acknowledgement: Study was funded by ITR division, ICMR New Delhi.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Category: Neurosciences: Neuro 1: F-18 fluorodeoxyglucose PET/CT in autoimmune encephalitis: A prospective study

Simran Kalra ¹, Madhavi Tripathi ¹, Manjari Tripathi ¹, Rajesh Kumar ¹, Ajay Garg ², C S Bal ¹

Introduction: Autoimmune encephalitis (AIE), constitute a group of inflammatory brain diseases wherein the antibodies bind to extracellular epitopes of cell-surface proteins or to intracellular antigens and cause reversible neuronal dysfunction or cell death via T-cell mediated mechanisms. F-18 Fluorodeoxyglucose PET/CT is emerging as a useful imaging adjunct to MRI in the initial diagnostic evaluation of Autoimmune Encephalitis, though it has not been included into the diagnostic criteria. In this study, we aim to evaluate the pattern of metabolic abnormality in AIE on F-18 FDG PET. The aim of the study is to evaluate the utility of F-18 FDG PET in Autoimmune Encephalitis (AIE) and to elucidate the pattern of metabolic abnormality obtained.

Materials and Methods: We prospectively evaluated 52 patients referred for F-18 FDG PET/CT with suspicion of AIE. Each patient underwent a detailed clinical evaluation, auto-antibody panel and MRI before referral. Patients finally included for analysis were the ones who subsequently received a clinical diagnosis of AIE and were treated with steroids, intravenous immunoglobulin, Rituximab or plasmapheresis.

Results: The mean age group of patients included was 38.5 + 22.6 years with 31 females and 21 males. 23 patients were antibody positive; 11 anti-NMDAR positive, 6 anti-LGI-1 positive, 2 each anti-GAD and anti-CASPR2 positive and one each anti-Hu and anti-SOX1 positive. Abnormal metabolic pattern on F-18 FDG was obtained in 23/23 (100%) antibody positive patients [Table 1]. The metabolic pattern in NMDARE was basal ganglia hypermetabolism with parieto-occipital hypometabolism. Ovarian teratomas were detected in two females with NMDARE on whole body PET. Metabolic pattern in anti-LGI-1 positive cases constituted basal ganglia and medial temporal lobe hypermetabolism. Cerebellar hypometabolism was seen in the anti-GAD positive case and bilateral basal ganglia hypermetabolism with lateral temporo-occipital hypometabolism was seen with anti-CASPR2 positivity. The anti-Hu positive patient revealed hypometabolism in bilateral prefrontal, temporal and posterior cingulate cortices, with no primary malignancy detected. PET was positive in 22/29 (75.8 %) antibody negative patients and revealed hypermetabolism in basal ganglia and mesial temporal cortices. MRI revealed abnormality in the form of hyperintensities on T2-FLAIR images in a total of 18 patients. PET was positive in a total of 23/30 (76 %) MRI negative cases.

Conclusion: FDG PET/CT revealed abnormality in 100% of patients clinically treated as AIE, with metabolic patterns which may be specific for antibody type, providing complementary information even in antibody negative patients (75.8%) and MRI negative (76 %) cases.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Neuro 2: Experience of (¹⁸F) F-L-6-fluoro-3, 4-dihydroxyphenylalanine ([18F] F-DOPA) synthesis using automated module

Kiran Dasary ¹, Raman Kumar Joshi ¹, Aishwarya Kumar ¹, R Gopinath ¹, Pardeep Kumar ¹

Introduction: [Fluoro-18]6-Fluoro-3, 4-dihydroxy-L-phenylalanine ([18F] F-DOPA) is a frequently used radiopharmaceutical for detecting neuroendocrine and brain tumors and for the differential diagnosis of Parkinson's disease. These are several types of precursors available for synthesis of 18F-FDOPA. In this study sharing on experience of 18F FDOPA synthesis using nucleophilic substitution method.

Materials and Methods: The 18F radioisotopes were produced with our in-house 16.5MeV Cyclotron (PETtrace 860, GE Healthcare, USA) by the proton bombardment on the enriched 18O water (from ABX Germany) [18O (p, n)18F] reaction. 6-l-[¹⁸F] FDOPA was produced using ABX -DOPA precursor (PE1336.0030) in the module. Around 2.5 Ci of the 18F was added to the module. The product was finally purified with a series of solid phase cartridges and tested for its PH by litmus paper, RCP by HPLC system (Dionex, ICS- 5000+, California, USA) was equipped with UV-Vis detector followed by radioactivity detector using a C18 column (5um 4.6×250, Shim-pack GWS, Shimadzu). For residual purity by GC (Scion 436 GC, Netherlands) with flame ionization detector (FID), for TBA content by HPTLC silica gel 60 F254 chromatography paper (Merck, New Jersey. USA, RNP by half-life with Dose calibrator (Capintec CRC-25PET, New Jersey. USA) and the endotoxin test was performed using cartridge on NexGen Endo safe PTS (Charles River, Massachusetts, USA).

Results: After each synthesis, the final product quality was evaluated for radiochemical purity by HPLC which was 97 ± 2%. The yield was 8 ± 2%, (n = 22) with a radiochemical purity (RCP) of result was satisfactory and complies European pharmacopeia. The results were given in the Table 1.

Conclusion: The produced [¹⁸F] FDOPA has good radiochemical purity, stability, and met all release specifications for clinical use. The yield may be low as automated module was adapted for the synthesis of 18F-FDOPA.

Table 1.

Results of radiochemical purity

Description	Method	Specification	Observation
Appearance	Visual inspection	Shall be clear/colorless	Clear
Final pH	pH paper	4.5-7.5	6.5±0.8
Radionuclide identity	Half-life method and 511KeV peak	110±5 min pass (must be passed)	110±4 min
RCP	HPLC	≥95 (%)	97±2 (%)
Chemical purity DMF Acetonitrile	Gas chromatography	410 (ppm)	110±10 (ppm)
Chemical purity DMF Acetonitrile	Gas chromatography	≤500 (ppm)	30±5 (ppm)
Chemical purity Levodopa	HPLC	0.02 (mg/mL)	0.02 (mg/mL)
TBA-HCO₃	TLC plate	0.26 (mg/mL)	<0.1 (mg/mL)
Bacterial endotoxin test	Endo safe NexGen (Charles river)	<175 EU/dose pass/fail	1±0.5 EU/dose pass

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TLC: Thin layer chromatography, RCP: Radiochemical purity, HPLC: High performance liquid chromatography, TBA: Tetrabutylammonium, DMF: Dimethylformamide

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Neuro 3: Statistical parametric mapping analysis of FDG-PET studies in autoimmune encephalitis

Roopal Sarraf Sonar ¹, Anil Kumar Pandey ¹, Simran ¹, Manjari Tripathi ¹, Madhavi Tripathi ¹, C S Bal ¹

Objectives: Early initiation of therapy in Autoimmune encephalitis (AIE) has good results. Timely diagnosis is therefore crucial but clinical diagnosis can be delayed for want of antibody results or if MRI is non-contributory. Metabolic patterns on F-18 Fluorodeoxyglucose positron emission tomography (FDG-PET) have proved useful to support the clinical diagnosis of AIE. Routinely visual analysis is performed but the confidence of interpretation can be enhanced by the use of more objective computer supported techniques like Statistical Parametric Mapping (SPM). We undertook this analysis to evaluate concordance between visual and SPM analysis of FDG-PET scans in AIE.

Materials and Methods: In this retrospective study, a total of 39 patients (age range of 9-75 years) with clinically suspicion of AIE, undergoing FDG-PET studies were included for analysis. Each scan was interpreted visually. This was followed by SPM analysis on a MATLAB platform. 28 normal controls were included from our normal brain database for SPM analysis. The metabolic pattern (hypermetabolism and hypometabolism) demonstrated on visual analysis and SPM was compared for cortical and subcortical regions.

Results: B asal ganglia and mesial temporal lobe hypermetabolism was detected in 17 and 9 patients respectively on SPM and showed almost perfect and fair concordance with visual analysis [Table 1]. Mesial temporal hypermetabolism was better demonstrated on SPM. Hypometabolism involving the frontal, parietal, occipital or temporal cortices showed moderate to substantial concordance between SPM and visual analysis.

Conclusion: SPM proved to be better than visual analysis for mesial temporal hypermetabolism as well as for demonstrating cortical hypometabolism in AIE, thereby supporting the utility of computer-supported reading with SPM.

Table 1.

Concordance between Visual and SPM analysis

Brain regions	Visual (%)	SPM (%)	Kappa coefficient	Concordance
Hypermetabolism
Basal ganglia	20 (51.28)	17 (43.58)	0.84	Almost perfect
Mesial temporal lobe	2 (5.12)	9 (23.07)	0.30	Fair
Hypometabolism
Frontal lobe	20 (51.28)	29 (74.35)	0.53	Moderate
Parietal lobe	15 (38.46)	24 (61.53)	0.56	Moderate
Occipital lobe	12 (30.76)	16 (41.02)	0.77	Substantial
Temporal lobe	9 (23.07)	13 (33.33)	0.75	substantial

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SPM: Statistical parametric mapping

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Neuro 4: Utility of F18-FET PET/MRI for differentiating treatment related changes from recurrence/residual, prognostication and as a follow up modality in glioma

Keerti Sitani ¹, Pardeep Kumar ¹, Archith Rajan ¹, Kiran Dasary ¹, Venkatesh Murthy ¹, Rose Dawn Bharath ¹

Introduction: Fluorine-18-fluoro-ethyl-tyrosine ([¹⁸F]-FET), an amino acid radiotracer, is used in neuro-oncological positron emission tomography (PET) imaging. Its use is more significant in cases of high grade gliomas where MRI in inconclusive and in differentiating recurrence from treatment related changes. The study aims at observing the utility of [¹⁸F]-FET simultaneous PET/MRI over MRI.

Materials and Methods: We have analyzed a data of 30 patients. All of them underwent [¹⁸F]-FET PET/MRI at our centre. A radioactivity of 5-7mci (185-259 MBq) was injected. The Scans were performed 30 minutes post injection. Standard MRI sequences were added like 3D FLAIR, T1-MPRAGE. PET imaging reconstruction was done using iterative reconstruction with 512 matrix, 5 iterations, FWHM-2. The standard uptake value (SUV) and tumor to background (TBR) was calculated in all the case for analysis.

Results: We analyzed a heterogeneous data of 30 patients, 20 females and 10 males, histopathological classification of tumor was done and showed in the Table 1. All the cases were post-operative. FET-PET showed increased radiotracer uptake in 27 cases. 3 cases showed no radiotracer uptake on PET. There was concordance noted in 28 cases between PET and MRI findings and discordance noted in 2 cases where PET findings were suggestive of recurrence and MRI findings suggestive of post-operative changes. Three cases had multiple PET/MRI scans available over multiple time points, where no recurrence was noted in either PET or MRI. Out of 30 cases, 24 cases were of high-grade tumors (III/IV), 3 were low grade I/II and in 3 cases grade was not specified. In high grade tumor, SUV_max was greater than 2.5 [Figure 1] and TBR greater then 2.0 (except two cases). In low-grade tumors, two of the cases showed a SUV of < 2.5 [Figure 2] and TBR <2.0 while two shoed higher than this.

Schematic of automated module for 90Y-DOTA-TATE

Conclusion: From the above data analysis, it can be concluded that, [¹⁸F]FET PET/MRI is superior to [18F]FDG (in view of low background in [¹⁸F]FET) and MRI in differentiating post operative changes from recurrence/residual disease. [¹⁸F]-FET can be used for following up studies of the same. Simultaneous [¹⁸F]-FET-PET-MR adds on to the diagnostic value and can be a useful tool as well to ascertain the grade of tumors hence can be valuable in prognostication though it needs larger sample size to further validate the study.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Neuro 5: Spatial patterns of F-18 M 104 Tau PET/CT and F-18 FDG PET/CT in suspected nonalzheimer disease cognitive impairment – A step towards unravelling the puzzle

S G Ravindra ¹, S Garg ¹, A Khurana ¹, J Jaleel ¹, M Tripathi ¹, A Gupta ¹, M Tripathi ¹, C S Bal ¹

Introduction: Biomarkers are now being increasingly used as measures of pathophysiology in dementia. Over the years, plenty of research has been carried out in the field of Tau PET radio-tracer development and imaging. However, significant lacunae exist in the literature regarding the use of F-18 ML104 PET/CT in patients with Non-Alzheimer disease cognitive impairment and its correlation with F-18 FDG PET/CT imaging.

Materials and Methods: A total of 10 patients – 4 with Fronto-Temporal Dementia (FTD), 4 with Vascular Dementia (VD), 1 with Cortico-Basal Syndrome (CBS) and 1 with Dementia with Lewy Bodies (DLB), based on clinical diagnosis, were recruited from neurology clinics of our tertiary care centre and included in this ambispective study from January 2017 to June 2022. Each patient underwent both F-18 ML-104 Tau PET/CT and F-18 FDG PET/CT imaging. Patterns of Tau retention and hypometabolism on FDG scans were evaluated visually and compared to see for any correlation.

Results: The mean age and gender distribution (male: female) of patients were as follows: 62.8 +/- 8.7 years (7:3). 3 patients with FTD showed hypometabolism in bilateral frontal lobes on FDG. On correlation with Tau imaging, increased Tau retention was noted in bilateral frontal lobes – consistent with behavioural variant FTD. 1 patient with FTD showed hypometabolism in bilateral anterior temporal lobes and anterior cingulate cortices. However, increased Tau retention was also noted in the same cortical regions in this patient – thus raising the possibility of AD in addition to semantic dementia variant FTD.1 patient with vascular dementia showed hypometabolism in right thalamic infarct with corresponding focal Tau accumulation in the same region. 3 patients with vascular dementia, showed areas of cortical hypometabolism on FDG suggesting regional neuronal dysfunction. Analysis of Tau retention pattern revealed increased periventricular white matter binding – consistent with vascular dementia. 1 patient with CBS showed asymmetric hypometabolism in left precentral region with increased Tau retention in the same area – consistent with CBS. 1 patient with DLB showed hypometabolism in parieto-temporo-occipital cortices with relative sparing of posterior cingulate – pattern consistent with DLB. However, Tau imaging did not reveal any abnormality.

Conclusion: Spatial patterns of F-18 ML 104 Tau PET/CT and its correlation with F-18 FDG PET/CT may help aid in the etiological diagnosis of Non-Alzheimer disease cognitive impairment and add to its accuracy. However, more studies on a wider population are required to validate the same.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Neuro 6: Software based evaluation of fluorine-18 fluorodeoxyglucose positron emission tomography brain studies in progressive supranuclear palsy using statistical parametric mapping

Sonu ¹, Anil Kumar Pandey ¹, Priyanka Sehrawat ¹, Nishikant A Damle ¹, C S Bal ¹, Madhavi Tripathi ¹

Introduction: The clinical syndrome of Progressive supranuclear Palsy (PSP) is difficult to differentiate from other atypical parkisonian syndromes and idiopathic Parkinsons disease (IPD) especially in the early stages of disease process. The utility of Fluorine-18 Fluorodeoxyglucose positron emission tomography (FDG-PET) has been suggested in this regard. The present study was undertaken to define the pattern of glucose metabolism on FDG-PET in PSP on visual analysis and using statistical parametric mapping (SPM) and evaluate the concordance between the two.

Patients and Methods: This was a retrospective single center study performed on 78 patients of PSP who were referred to our departmentfor brain FDG-PET. 28 healthy controls were included for SPM based statistics. Each scan was read visually and analysed using SPM.

Results: The spatial pattern of metabolism on the visual read included prefrontal and anterior cingulate cortices, basal ganglia and midbrain. SPM analysis reiterated this pattern with hypometabolism in basal ganglia, midbrain and thalami in a larger number of patients than simple visual analysis. This was particularly so for the thalamus. Concordance between SPM and visual read was fair for prefrontal and anterior cingulate cortices, basal ganglia and midbrain and slight for the thalamus [Table 1].

Table 1.

Concordance between SPM and visual read

Brain regions	Hypometabolism on SPM (%)	Hypometabolism on visual analysis (%)	Percentage of concordance
Prefrontal	59 (74.6)	63 (79.7)	74.68
Anterior cingulate	69 (86.0)	41 (51.8)	62.82
Basal ganglia	63 (81.0)	56 (70.8)	73.75
Mid brain	48 (60.7)	43 (54.4)	65.82
Thalamus	64 (81.0)	20 (25.3)	41.55

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SPM: Statistical parametric mapping

Discussion: SPM proved to be better than visual reading in PSP as it revealed hypometabolism in a higher number of patients in anterior cingulate cortices, caudate/basal ganglia, midbrain and thalamus, thereby demonstrating the utility of computer-supported reading with SPM.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Neuro 7: A head-to-head comparison of (11C) methionine PET-MR with (99mTc)-methionine SPECT-CT in glioma patients

Pardeep Kumar ¹, Aishwarya Kumar ¹, Chandana Nagaraj ¹, Jitender Saini ¹, Sandhya Mangalore ¹, Chandrajit Prasad ¹, Archith Rajan ¹, Nishanth Sadashiva ¹, Manish Beniwal ¹, Vani Santosh ², Puja Panwar ³, Anil K Mishra ³

Introduction: A single vial of Bis-methionine-DTPA (MDM)] was prepared by Mishra et al and tested clinically in breast cancer and glioma patients. In order to study the diagnostic efficacy of [99mTc]-methionine, we had done head-to-head comparison of [99mTc] methionine with [11C] methionine in glioma patients.

Methods: 21 patients were enrolled for the study, out of which 10 are post-operated patients (8 male and 2 female) and other group has 11 patients (3 male and 8 female). All the patients were undergone [99mTc] methionine SPECT-CT (Symbia – T6, Siemens) followed by [11C] methionine PET-MR (mMR Biograph, Siemens) within 2.3 + 0.5 days. The study was approved by Institute ethic committee and scans were performed after obtaining patients consents. The scans were interpreted separately by an experienced nuclear medicine physician and a radiologist. For the analysis, images were processed using OsiriX MD software (Pixmeo SARL, Switzerland). Mann-Whitney nonparametric test was used to determine the level of significance for each index (T/NTmean, T/NTmax, SUVmean, SUVmax, L/Nmean, and L/Nmax) in differentiating tumor recurrence with radiation necrosis.

Results: For Post-OP gliomas, all the indices significantly discriminated tumor recurrence from radiation necrosis (P = 0.002 for T/NTmean, p = 0.044 for T/NTmax, p = 0.044 for L/Nmean, p = 0.022 for SUVmax, P = 0.044 for L/Nmax) except for SUVmean (p = 0.089). Likewise, with respect to Pre-OP gliomas, all the indices significantly discriminated low-grade glioma from high grade glioma (p = 0.024 for T/NTmean, p = 0.012 for T/NTmax, p = 0.006 for SUVmean, p = 0.006 for SUVmax, p = 0.012 for L/Nmax) except for L/Nmean (p = 0.067). [99mTc] methionine has sensitivity and specificity of 87% and 100% respectively in post-op cases to differentiate recurrence from necrosis as compared to 72% and 60% in pre-op cases. A significant and strong positive correlation (Spearman's coefficient (rs) = 0.611, P < 0.004) was observed between Vt PET and Vt MR. Likewise, a significant and strong positive correlation (Spearman's coefficient (rs) = 0.610, P < 0.004) was found between Vt SPECT and Vt MR. Showed a representative image comparison between MR, PET, and SPECT.

Conclusion: The dice coefficient showed the concordance between the SPECT and PET findings especially for high grade tumor. [99mTc]-methionine can be an economical amino acid SPECT tracer for differentiating recurrence from necrosis.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Neuro 8: Pattern of interictal brain perfusion defects in children with drug-resistant epilepsy – An institutional experience

S Sanisetty ¹, P K Panda ¹, P Pradeep ¹, Manishi L Narayan ¹

Introduction: Cerebral perfusion and metabolism are coupled in most physiologic and pathologic conditions, which strongly correlate with the intensity of neuronal activity. Imaging of brain perfusion with ictal, peri-ictal & interictal SPECT plays a key role in the localization of epileptogenic region and guidance for the subsequent management, especially in drug-resistant epilepsy, where, EEG, MRI& clinical findings are either discordant or normal. We have retrospectively evaluated the brain perfusion patterns in children with drug-resistant epilepsy referred to Nuclear Medicine department, AIIMS, Rishikesh.

Aims and Objectives: To study the patterns of interictal brain perfusion on 99mTc-ECD SPECT in children of age 1-18 years with drug-resistant epilepsy (uncontrolled seizures on >2 AED).

Materials and Methods: Interictal brain perfusion SPECT was performed according to standard protocol, using 0.2 to 0.3 mCi / kg with a minimum dose of 3 to 5 mCi of 99mTc-ECD. Tracer was injected intravenously at rest, during the seizure-free period (> 24 hrs) in supine position and brain SPECT was acquired 45 mins post-injection. Reconstructed images were analyzed by an experienced Nuclear Medicine Physician. Location, as well as the severity of perfusion defects, were noted and correlated with respect to the duration of disease, EEG, clinical and other imaging findings.

Results: A total of 19 patients (14 males & 5 females) with drug-resistant epilepsy with a mean age of 10+5 (range 1-18) years were analyzed. 9/19 (47%) patients had normal MRI brain study and 4/19 (21%) patients had normal EEG records, while in 2 patients both MRI and EEG were unremarkable. In all patients interictal brain perfusion SPECT was abnormal. Medial temporal lobe hypoperfusion was seen in all patients. However, 3/19 patients had other focal areas of hyperperfusion in addition to temporal lobe hypoperfusion. 6/19 patients had involvement of one hemisphere and 13/19 showed perfusion abnormalities in both hemispheres. Moderate to severe perfusion defects were seen in 13 patients. SPECT findings were concordant in 12/19 (63%) of cases.

Conclusion: Interictal SPECT was abnormal in almost all patients and, SPECT was able to provide additional information for diagnosis in the current patient group, where other clinical, lab findings, EEG & MRI were either discordant or unremarkable. It was observed that the patients with a duration of onset of symptoms <1 year had mild or subtle perfusion defects, while those with disease duration of >1 year had moderate to severe perfusion defects. Also, in a substantial number of cases bilateral hemispheric involvement and additional findings were noticed.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Neuro 9: Synthesis of fluorine-18 flumazenil using isotopic approach

Riptee Thakur ¹, Aishwarya Kumar ¹, Raman Kumar ¹, Pardeep Kumar ¹

Introduction: fluorine-18 [¹⁸F]-flumazenil (FMZ) has been used for the assessment of the gamma amino butyric acid (GABA) receptors by positron emission tomography (PET). We have aimed at radio-synthesis of 18F-flumazneil using isotopic exchange method.

Methods: ¹⁸F was produced by standard nuclear reaction using [¹⁸O(p,n)¹⁸F] in GE PETtrace cyclotron. The flumazenil was procured from Sigma-Aldrich, USA. The radio-fluorination was standardized for various parameters like temperature (110-160°C), precursor concentration (3-10 mg). The crude mixture was diluted with acidic water and passed through various combinations of the SPE cartridges (tC18 light) and final product eluted by using 2.0 mL of 20% ethanol/ phosphate buffer in an automated FX2N module. The final preparation was passed through cathivex 0.22μ and final radiochemical purity was calculated by using Radio-HPLC. The endotoxin levels were evaluated by using Endosafe PTS cartridges and sterility by incubating the preparation in the soy broth for 14 days at 37°C.

Results: The labeling was found to be maximum by using K¹⁸F/kryptofix complex in the acetonitrile at 160°C for 20 min. An equimolar concentration of [K/K2.2.2]⁺18F^-/precursor was used and the incorporation of ¹⁸F in the flumazenil was found to be 12 ± 3%. The total synthesis time was 40 minutes. The radiochemical purity was 97 ± 3 % as evaluated by Radio-HPLC with retention time at 15.4 ± 0.3 min (n = 3). We have also used integrated HPLC method along though the total synthesis time and was increased by 15 minutes. The yield was 15 ± 3 % which is higher as reported earlier by our group using nitromazenil though it decreased when we used HPLC purification method. The endotoxin level was 1.0 endotoxin unit per dose and no turbidity was observed in soy broth for 14 days.

Conclusions: [¹⁸F] flumazenil was synthesized with higher radiochemical purity and a simple automated method using isotopic exchange method.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Category: Oncology and PET: Onco 1: Discovery and preclinical evaluation of a ⁸⁹Zr labeled human antibody against TIP1 for cancer targeting

A K Singh ¹, C D Lewis ¹, C A W V Boas ¹, P N Jethva ¹, B E Rogers ¹, D E Hallahan ¹, V Kapoor ¹

Introduction: Lung cancer is the most common type of malignancy and the leading cause of death worldwide. There is an unmet need for therapies to improve lung cancer outcomes without causing additional toxicities. We discovered Tax-interacting protein 1 (TIP1) as an antigen that plays a role in lung cancer progression and resistance to therapy. TIP1 is a targetable cell surface protein used for imaging and delivery of cytotoxic cancer therapies. We developed fully human antibodies (Ab) that bind specifically to TIP1. This study aimed to evaluate our lead anti-TIP1 human antibody for targeting lung cancer in vitro and in vivo.

Materials and Methods: We used our in-house antibody-phage display library for biopanning and discovering an anti-TIP1 single-chain variable antibody (scFv) that was then formatted into an intact human IgG1 antibody. The lead human TIP1 antibody was expressed and purified using the ExpiCHO mammalian expression system. The intact mass of the purified antibody and its glycosylation status was evaluated by native spray mass spectrometry analysis. We evaluated the binding affinity of the human anti-TIP1 antibody to TIP1 protein by ELISA and BIAcore. Cell surface binding to cancer cells was performed by flow cytometry. Human anti-TIP1 antibodywas conjugated with desferoxamine (DFO) at a molar ratio of 1:10 and labeled with ⁸⁹Zr. The binding of [⁸⁹Zr] Zr-DFO-antibody was evaluated in the A549 and H460 lung cancer cells using an excess of the unlabeled antibody as a blocking agent. Mice bearing patient-derived xenografts (PDX) lung tumors (n =6) on the rear flank were injected i.v. with 50 μCi of the [⁸⁹Zr] Zr-DFO-antibody. Small animal PET imaging was conducted 2 and 7 days after injection, and the tumor and muscle (background) SUVs were calculated.

Results: We obtained 95% pure anti-human TIP1 Ab as analyzed by size-exclusion chromatography-HPLC (SEC-HPLC). Mass spectrometry confirmed the intact mass and glycosylation pattern of the anti-TIP1 human IgG1. The Ab is bound to recombinant TIP1 protein and cancer cell surface with high affinity. NIR imaging showed tumor-specific antibody binding and clearance from the liver. The radiochemical purity of the [⁸⁹Zr]Zr-DFO-antibody product was 99.9%, and the molar activity was 11.54 MBq/nmol with a radiolabeling yield of 91.4%. Both A549 and H460 cell lines demonstrated specific binding as >70% inhibition was observed when the unlabeled antibody was added. PET imaging on day 2 showed a tumor SUV of 1.77 ± 0.30 and muscle of 0.30 ± 0.05, the difference was statistically significant (P = 0.0021), and on day 7, the values were 1.18 ± 0.41 and 0.18 ± 0.05 (P = 0.0019), for tumor and muscle SUV, respectively. The ratio of SUV tumor to SUV muscle increased from 5.8 at two days to 6.3 at seven days.

Conclusions: The human anti-TIP1 antibody targets lung cancer cells in vitro and PDX tumors in vivo. The antibody retained antigen-binding potential following labeling with NIR dye and ⁸⁹Zr. This antibody can be used for therapy when conjugated with appropriate therapeutic radionuclides. Next, we will perform IND enabling studies with the lead anti-human TIP1 antibody.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 2: Role of ⁶⁸Ga-PSMA-11 PET/CT in early response prediction to anti-vascular endothelial growth factor receptor tyrosine kinase inhibitor therapy in metastatic renal cell carcinoma

Piyush Aggarwal ¹, Harmandeep Singh ¹, Chandan Krushna Das ¹, Ravimohan Suryanarayan Mavuduru ², Anupam Lal ³, Ujjwal Gorsi ³, Rajender Kumar ¹, Bhagwant Rai Mittal ¹

Introduction: RCC is a highly vascular tumor and anti-vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors targeting tumor neoangiogenesis form the first-line therapy of metastatic RCC (mRCC). Owing to the cytostatic nature of these drugs, structural changes require many months to develop and lead to underestimation of treatment response on CT using RECIST 1.1. There is an unmet need for better markers to predict and assess treatment response earlier to avoid unnecessary costs and side effects in non-responders. Although ¹⁸F-FDG has shown promising results, other angiogenic imaging tracers such as ⁶⁸Ga-PSMA-11, are also being evaluated. This study aims to assess the role of ⁶⁸Ga-PSMA-11 PET/CT as an angiogenesis imaging marker in predicting early response to anti-VEGFR TKI therapy in mRCC and compare it with the CT-based RECIST criteria at three months.

Materials and Methods: Patients diagnosed with metastatic RCC on preliminary workup and planned to undergo TKI therapy were enrolled in this prospective study. After taking informed consent, ⁶⁸Ga-PSMA-11 PET/CT scans were acquired at baseline, at one and three months after the start of therapy. PET/CT images were analysed qualitatively and quantitatively using parameters: SUVmax, SUVmean, SUVpeak, PSMA-derived Tumour Volume (PSMA-TV), and Total Lesion PSMA (TL-PSMA). The PET-based response was assessed using modified PERCIST criteria, and the CT-based response using RECIST criteria 1.1. Statistical analysis was done using Statistical Package for Social Sciences (SPSS) version 26.0.

Results: A total of 27 patients were included in the final analysis. Twenty-one (77%) and four (15%) patients had clear cell and papillary RCC, respectively; while eosinophilic variant and collecting duct RCC were observed in one (4%) patient each. Treatment responders [complete response (CR) and partial response (PR)] based on RECIST 1.1 had a higher baseline SUVmax (13.9 vs 8.1, p = 0.07), SUVmean (10.2 vs 5.7, p = 0.11) and SUVpeak (9.7 vs 5.7, p = 0.12) uptake than non-responders, however no statistically significant difference was observed. PET at one-month post-treatment revealed PR in 25 of 27 (~93%) patients, SD in one patient (~4%), while in one patient, SUVmean of target lesions at baseline showed a decrease of ~73%; however, a new brain lesion appeared, amounting to an overall disease progression (PD). CT at three months revealed PR in nine patients (~33%), SD in 14 patients (~52%), and PD in four patients (~15%). The PET response at one month and CT response at three months were discordant in 16 of 27 patients (~59%), with a significant disagreement and poor concordance between the two (k = 0.08, p = 0.3) modalities.

Conclusion: Early response assessment to tyrosine kinase inhibitor therapy is feasible using ⁶⁸Ga PSMA-11 PET-CT in metastatic RCC, and response assessment on PSMA PET using modified PERCIST shows significant disagreement with CT at three months using RECIST 1.1.

Acknowledgement: We thank Indian Council of Medical Research (ICMR) for the research grant support.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 3: Spectrum of 18 F fluorodeoxyglucose positron emission tomography computed tomography imaging in diseases with peritoneal involvement – An institutional experience

M G Vishnoi ¹, B K Singh ¹, Asima Bushra ¹, Devika Gupta ¹

Introduction: The aim of this study was to assess the value of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in diseases with peritoneal involvement to determine exact cause and extent of peritoneal involvement. This will help in diagnosis (to determine site of biopsy), to detect extent and type of peritoneal involvement (Diffuse or nodular) and response assessment (post therapy) as well.18F-FDG PET/CT is useful for detecting the underlying cause of peritoneal involvement. Peritoneal thickening may be because of benign or malignant causes. PET/CT imaging is not only complementary to conventional imaging, but also may be more sensitive because the metabolic alterations of malignant tumors may precede gross anatomical changes. However, 18F-FDG accumulates not only in malignant tumors but also in several benign lesions that may mimic malignant lesions and thus limit the specificity of 18F-FDG PET/CT imaging.

Materials and Methods: This was a retrospective analysis of 06 patients subjected to 18F FDG PET CT Scan for different disease process. Age ranges from 47 years to 69 years with 01 male and 05 female patients with peritoneal involvement on PET CT scan in last 06 months. PET/CT Whole body scanning was performed by using a whole body PET/CT scanner (GE Discovery 690). All patients received an intravenous injection of 3.7 MBq/kg of 18F-FDG after fasting at least 6 hours and resting for 1 hour.

Results: Patients were assessed based on of multiple factors, including the patient's symptoms, the physical examination findings, laboratory test results conventional imaging findings and PET T scan findings. Out of six cases, 03 were solid organ malignancies with 02 patient of Carcinoma Ovary and one of carcinoma stomach, one patient of peritoneal mesothelioma whereas one patient was of benign peritoneal inflammatory disease.

Conclusion: Early diagnosis of the primary lesion is crucial for making an effective treatment plan and predicting prognosis. Peritoneal biopsy may have a relatively high diagnostic accuracy, but its utility is limited because of its invasiveness. PET/CT can be used to detect abnormal uptake of the whole body. Thus, PET/CT offers the advantage of locating both the primary lesions and peritoneal thickening. 18F-FDG PET/CT scan is able to characterize peritoneal inflammation and thickening of undetermined origin in most of cases. 18 F FDG PET CT Scan being a whole body imaging modality and routinely performed investigating modality help in detection and assessment of primary abnormal FDG avid lesion in the body, to determine site of biopsy from most metabolic active site and post treatment response assessment or detection of recurrence as well. This study has some limitations. First, the study was retrospective and there was unavoidable selection bias. Second, we had a small and heterogeneous sample, with patients having a variety of different malignancies.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 4: Role of 18F FDG PET CT scan in synchronous dual malignancies diagnosed over 01 year: Solid-solid and solid-hematological tumors, is it rare?

M G Vishnoi ¹, B K Singh ¹, Asima Bushra ¹, Devika Gupta ¹

Introduction: The occurrence of synchronous dual malignancy is not rare. There is an increasing trend seen probably due to improved diagnostic modalities compounded by genetic susceptibility & environmental impact. Dual malignancies are categorised as synchronous if the interval between them is less than or equal to 06 months and metachronous, if the interval is more than 06 months. We here have highlighted six varied cases reported over a period of one year detected with help of 18F FDG PET CT scan.

Materials and Methods: This was a retrospective analysis of 06 patients diagnosed with help of 18F FDG PET CT Scan. Histologically & haematologically confirmed synchronous double malignancy over last one year at our centre.

Results: Out of six cases, four were pure solid organ malignancies whereas other two were solid-hematological malignancy combinations. Two cases were of papillary thyroid carcinoma with coexisting invasive Breast carcinoma, third was a squamous cell carcinoma of Larynx & renal cell carcinoma, fourth was squamous cell carcinoma of cervix with invasive carcinoma breast and fourth and fifth were both carcinoma stomach with AML M4 & MDS-MPN respectively.

Conclusion: The present series suggests that the occurrence of second synchronous malignancy is not rare in Indian cancer patients. The double malignancies can occur at any stage and for any type of cancer. Hence, we wish to highlight that the clinicians should always be aware and have high index of suspicion for second malignancy. 18 F FDG PET CT Scan is very useful modality as it is being a whole body imaging and routinely performed investigating modality in malignancies, helping in assessment of response, recurrence and detection of abnormal metabolic active focus in the scanned region of body.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 5: Role of textural analysis of pretreatment 18F FDG PET/CT in response prediction in oesophageal carcinoma patients

Ajit Mishra ¹, Rutuja Kote ¹, Mudalsha Ravina ¹, Amit Kumar ², Yashwant Kashyap ², Sarin Krishna ¹, Subhajit Dasgupta ¹, Moulish Reddy ¹

Introduction: PET/CT is routinely used for staging, response assessment and surveillance in oesophageal carcinoma patients. The aim of this study was to investigate whether textural features of pre-treatment 18F-FDG PET/CT images can contribute to prognosis prediction in carcinoma oesophagus patients.

Methods: This is a retrospective study of 30 diagnosed carcinoma oesophagus patients. These patients underwent pre-treatment 18F-FDG PET/CT for staging. The images were processed in a commercially available textural analysis software. ROI was drawn over primary tumor with a 40% threshold and was processed further to derive 42 textural and radiomic parameters. These parameters were then compared between progression group and non-progression group. ROC curves were used to identify cut-off values for textural features with a p value <0.05 for statistical significance.

Results: A retrospective study of 30 primary carcinoma oesophagus patients was done. Patients were followed up after chemo-radiotherapy and they underwent follow up PET/CT. On the basis of their response, patients were divided into progression group and non-progression group. Among them, 15 patients showed disease progression and 15 patients were in non-progression group. 10 textural analysis parameters turned out to be significant in prediction of disease progression. Cut off values were calculated for these parameters according to the ROC curves [Table 1].

Table 1.

Cut off values for textural analysis parameters which were significant for predicting disease progression

Parameter	Cut off
GLZLM_LGZE	44.9
GLZLM_LGZE	0.006
GLZLM_SZLGE	0.0032
GLZLM_LZLGE	0.185
GLRLM_LRE	1.31
GLRLM_LGRE	0.0058
GLRLM_SRLGE	0.005496
GLRLM_LRLGE	0.00727
NGLDM_Busyness	0.75
GLCM_Homogeneity	0.37

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Conclusions: Textural analysis parameters could provide prognostic information in carcinoma oesophagus patients. Larger multi centre studies are needed for better clinical prognostication of these parameters.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 6: Role of FDG PET-CT in the evaluation of extraskeletal involvement in plasmacytoma

Sneha Prakash ¹, Shamim Ahmed Shamim ¹, Tejesh Pratap Singh ¹, Madhavi Tripathi ¹, Rakesh Kumar ¹, C S Bal ¹

Introduction: Extraskeletal involvement in plasmacytoma or extramedullary plasmacytoma (EMP) is an uncommon presentation of plasmacytoma with tumor progression, prognosis and management protocol different from isolated skeletal plasmacytoma. Currently, there is no consensus in the imaging of extramedullary plasmacytoma. FDG PET-CT has been shown to be helpful in detecting lymph nodal involvement and additional lesions in distant sites in EMP, leading to a change in management decisions. However, the literature documenting the role of FDG PET-CT in evaluating EMP is limited to only a small number of cases. We undertook this study to analyze the role of FDG PET-CT in evaluation of extramedullary plasmacytoma, keeping in mind that our study would add to the limited existing literature.

Materials and Methods: We systematically analyzed the database of our institute and identified patients with histopathologically proven plasmacytoma referred for FDG PET-CT from the year 2017 to 2021. The patients with extramedullary plasmacytoma were retrospectively included in the study. The scans were independently read by two experienced nuclear medicine physicians and significant findings were correlated with biopsy results, further work-up and/or clinical and imaging follow-up.

Results: A total of 52 patients with plasmacytoma were referred for FDG PET-CT. Out of these patients, extramedullary involvement was detected in 11 patients (23%) with an age range of 41-68 years (mean- 53 years). 10 (91%) patients were male while 1 (9%) patient was female. Among these 11 patients with extraskeletal plasmacytoma, 6 (55%) patients also had skeletal involvement. Lymph nodal involvement was seen in 6 patients (55%) with supraclavicular/cervical lymph nodes detected in 4 (67%) patients, mediastinal lymph nodes detected in 3 (50%) patients, abdomino-pelvic lymph nodes detected in 1 (17%) patient, abdominal lymph nodes detected in 1 (17%) patients and pelvic lymph nodes detected in 1 (17%) patient. A total of 3 (27%) patients with plasmacytoma had abdominal involvement, with 1 patient having mesenteric plasmacytoma, 1 patient with pancreatic and perinephric plasmacytoma and 1 patient with multiple soft tissue deposits in the abdomino-pelvic region. Subcutaneous deposits were detected in 3 patients (27%) with 1 patient having multiple deposits in the subcutaneous tissue of face, scalp, chest, abdominal wall, upper and lower limbs, 1 patient having subcutaneous deposits in the chest wall and right arm and 1 patient having presternal involvement from an anterior mediastinal plasmacytoma. Instramuscular deposits were detected in 2 patients (18%), with 1 patient having multiple instramuscular deposits involving muscles of mastication, neck, chest, abdominal wall, back, upper and lower limbs while 1 patient had an isolated intramuscular deposit in right pectoral muscle. Two patients (18%) had lung involvement with parenchymal nodules and consolidation. Two patients (18%) had pleural involvement. Isolated hypopharyngeal plasmacytoma was seen in 1 patient involving the false vocal cord. Anterior mediastinal plasmacytoma invading the sternum and presternal region was seen in 1 patient.

Conclusion: FDG PET-CT seems to be a useful imaging modality in the evaluation of extramedullary plasmacytoma, especially in the detection of additional lesions that might lead to a change in the treatment decisions.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 7: Potential role of empagliflozin in patients with controlling the deranged blood sugar before an 18F-FDG PET-CT – A pilot study

Abhishek Mahato ¹, Anurag Jain ¹, V S Prakash ¹, Rajesh Nair ¹, Harkirat Singh ¹

Background: 18F-FDG PET-CT is a novel imaging modality for evaluation of patients with cancer or inflammatory conditions offering a one stop shop solution. The underlying principle of imaging is the preferentially increased Insulin independent glucose consumption by cancer cells. Thus one of the factors which decreases the sensitivity of an 18F-FDG PET-CT is an increase in the blood sugar level, making the evaluation suboptimal. A significant percentage of cancer patients have Diabetes Mellitus II (DM-II) as a co-morbid condition which is often detected during the clinical evaluation for diseases. Such patient population have elevated RBS (Random Blood Sugar) not meeting the PET-CT evaluation criteria despite prolonged fasting on the day of test, and have to be rescheduled at a later date. This causes delay in the oncological evaluation which further delays the therapy initiation. Empagliflozin is a novel SGLT2 (Sodium Glucose Co-Transporter2) inhibitor which prevents the tubular reabsorption of glucose and increases renal glycosuria resulting in decreased blood sugar. This drug does not cause significant hypoglycemia or increases the insulin secretion. This study was initiated to evaluate the efficacy of the drug in decreasing the blood sugar of the patient on the day of the scheduled scan.

Materials and Methods: Patient detected with RBS > 200mg/dl on the day of the scheduled scan were included in the study. The patient were administered two tablets of 10 mg Empagliflozin and kept under observation. Samples for RBS were taken at 2nd and 4th hour post administration. Also these patients were scheduled as the last patient for the day provided their RBS was < 200mg/dl. The primary outcome was change in RBS values in the patient cohort and evaluation of PET SUV values with the rest of the patients scheduled on the day. Secondary outcome was assessment of any side effects in the patients. The images were also analysed for any altered 18F-FDG uptake in the patients.

Results: Total of 05 patients were found to have deranged blood sugar (RBS > 200mg/dl; irrespective of being on medication) and did not meet the evaluation criteria for a PET-CT scan on the scheduled day. Following the administration of the drug, all five patients were able to fulfill the criteria for undergoing a PET-CT scan. No obvious side effect was noted in any of the patient. The SUV values of the patient cohort was comparable with the rest of the patient scanned on the day.

Conclusion: In this pilot study, 20mg of Empagliflozin (02 tablets of 10mg) appears to be a safe and effective method of achieving rapid decrease in the RBS without causing hypoglycemia or hyper-insulinemia. It can be safely employed in the subset of population with RBS between 201-300 mg/dl to safely bring the sugar levels to acceptable levels RBS <200mg/dl and fulfill the FDG PET-CT criteria as per EANM norms.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 8: FAPI-04 for colorectal cancers – A dawn of new era

A Prashanth ¹, S Kumar ¹, E Prasad ², S Kalyan ²

Aim: To evaluate the role of Ga-68 FAPI 04 PET CT (FAPI) in colorectal cancers (CRC) in terms of diagnostic accuracy and impact on clinical management. FAPI is compared with FDG PET CT and conventional imaging in staging, restaging, recurrence detection and response evaluation of CRC.

Methods: Twenty-Nine consecutive patients of histopathologically confirmed primary or relapsed colorectal cancer were included in the study. Patients who underwent FAPI PET CT and either FDG or CECT/MRI within a span of 3 days were included. Primary lesions, recurrence sites, lymph nodes, and metastatic lesions were recorded on both scans. SUVmax was measured from both primary and metastatic sites. Peritoneum, mesentery, perihepatic, perisplenic and omental deposits were clubbed together and denoted as peritoneum. Histopathological evaluation was considered reference standard for staging. Composite clinical, biochemical and imaging follow-up was considered as reference standard for relapse.

Results: 7/29 (24%) patients were upstaged from stage III to stage IV after FAPI PET CT. The sensitivity of FAPI in primary and recurrence detection is 100% compared to 89% for FDG/conventional imaging. For nodal metastasis, a detection rate of 90% for FAPI and 81% for FDG PET CT was identified. The overall sensitivity of FAPI stands at 98% with accuracy at 95% whereas for FDG/conventional imaging the sensitivity and accuracy are 78% and 77% respectively with p<0.002. Significant difference was noted in the detection of peritoneal metastasis (96% vs 66%, P <0.005).

Conclusion: Ga-68 FAPI 04 PET CT showed higher sensitivity and accuracy in evaluation of primary CRC, recurrence detection, lymph nodal metastasis & especially peritoneal disease in comparison with FDG PET CT and conventional imaging. FAPI PET CT also provides superior lesion detection due to less background and absent bowel activity. This resulted a significant impact on clinical management. These results suggest that FAPI PET CT can be routinely used in colorectal malignancies.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 9: How does FDG PET/CT fare in uncommon (nonadeno and nonsquamous) uterocervical and pelvic cancers

S Arya Nair ¹, V Rangarajan ¹, S Shah ¹, A Agrawal ¹, A Puranik ¹, N Purandare ¹, V Rangarajan ¹

Introduction: The guidelines for management of uncommon histopathological varieties of gynecological cancers including peripheral neuroectodermal tumors (PNETs), uterine sarcomas, neuroendocrine carcinomas, etc. are not well established due the rarity of these tumors. We aim to evaluate ¹⁸FDG PET/CT in non- adeno, non-squamous uterocervical and pelvic cancers with regard to metabolism, site wise distribution of nodal and distant metastases for each histopathological types; and calculate the sensitivity and specificity of ¹⁸FDG PET/CT for these histopathological subtypes.

Materials and Methods: Retrospective, observational study where 71 patients with histologically proven non-adeno, non-squamous uterocervical and pelvic cancers were recruited. Patients underwent 18F FDG PET/CT at either staging, for treatment response or for evaluation of recurrent disease. The FDG uptake of primary, the sites of nodal and distant metastases with their FDG uptake were noted for various histopathologies of the primary tumour. The sensitivity, specificity, positive predictive value and negative predictive value of FDG PET/CT were calculated in comparison with conventional imaging modalities like CT scan or with histopathological reports as the standard or a follow up.

Results: The sites of cancer in the 71 patients included, 49 (69%) uterine, 7 (9.9%) cancer of adnexa, 6 (8.5%) each with cancer of cervix and pelvis and 3 (4.2%) cancer of vagina. Distribution according to histopathology – 54 (76%) sarcoma, 11 (15.5%) PNET and 6 (8.5%) NEC (neuroendocrine carcinoma) of the genital tract. 18FDG PET/CT was done in 50 (70.4%) cases for staging (some incidentally detected on surgical histopathology); 11 (15.5%) for restaging and 10 (14.1%) in post chemotherapy/radiation therapy for response evaluation. Of the 71 patients evaluated, 21 (29.6%) had nodal metastases and 48 (67.6%) patients had distant metastases on 18FDG PET/CT scan. Out of the 44 (62%) patients who had a discernible primary tumor, the mean SUVmax was 15.6±11.4. For nodal metastases, the mean SUVmax was found to be 10.18±5.0. 18FDG PET/CT showed 93.3% sensitivity, 87.5% specificity, 66.7% positive predictive value, 98% negative predictive value and 88.7% accuracy for nodal metastases compared with the standard. For distant metastases, the mean SUVMAX was found to be 1.4±0.55. 18FDG PET/CT showed 95.5% sensitivity, 80.8% specificity (improves to 98.0% if lung nodules detected on breath-hold chest CT are taken into consideration), 89.6% positive predictive value, 91.3% negative predictive value and 90.1% accuracy for distant metastases compared with the standard. The lungs and peritoneum were found to be the most common sites of distant metastases (30.35% each). Total percentage of extrapelvic metastases: 69.65%.

Conclusion: 18F FDG has a high sensitivity, specificity and accuracy for uncommon histopathological subtypes of non - adeno and non-squamous uterocervical and pelvic cancers. The detection of extrapelvic metastases in cases considered to be locoregional disease may result in a change of management in these patients who were previously imaged only by locoregional standard imaging modalities, especially subtle peritoneal lesions which are usually equivocal on conventional imaging.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 10: Metabolic preparation of cardiac ¹⁸F-FDG PET study: Comparison between intravenous glucose infusion method and oral glucose method in terms of preparation time and image quality

Ananya Shukla ¹, Aftab Hasan Nazar ¹, Sanjay Gambhir ¹, Sukanta Barai ¹, Manish Ora ¹, Anup Kumar ¹

Introduction: Metabolic preparation (MP) of the patient undergoing cardiac PET study is very crucial for accurate diagnosis which is time-consuming and employs cumbersome methods. The study aims to compare the IV glucose method for MP of cardiac ¹⁸F-FDG study and compare the image quality with the oral glucose loading method.

Materials and Methods: The study population consisted of patients who were referred for cardiac viability study. IV glucose method employed intravenous glucose infusion based on the patient's baseline blood glucose. Insulin was administered intravenously post glucose challenge before ¹⁸F-FDG injection for cardiac viability imaging. The diabetic patients who arrived with fasting blood glucose <150 mg/dl were prepared using intravenous glucose loading. While all the patients with fasting blood glucose >150 mg/dl, were not administered glucose intravenously, and only intravenous insulin was administered according to insulin protocol. If after 10min of insulin administration the serum glucose had then declined by 20mg/dL, then 10mCi ¹⁸F-FDG were injected. Post ¹⁸F-FDG injection, Image acquisition was done using Siemens biograph 64 slices PET/CT utilizing LSO crystal to determine ¹⁸F-FDG uptake. The age-matched control group was collected retrospectively from our database of patients, who underwent conventional oral glucose methods for metabolic preparation. Images acquired were visually assessed by two experienced nuclear medicine physicians and quality scores were given according to a three-point scale (3=Good, 2=Average, 1=Poor). Statistical analysis was done using SPSS 26.0 for windows.

Results: Using the intravenous glucose loading protocol, we found that the median MP time of the patient was reduced to 59 minutes as compared to the oral glucose loading method in which the patients had a median MP time of 140 minutes. There was no significant difference in image quality between the two groups. Thus, the Intravenous glucose loading and insulin administration protocol reduced the MP time by 58% as compared to the oral glucose challenge and it also offered average to good image quality in 87.5 % of the patients.

Conclusion: The MP method using intravenous glucose and insulin significantly reduced MP time with quality images as good as oral methods. It will be beneficial in increasing throughput in a busy Nuclear Medicine Department and adds to the patients & caregiver comfort.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 11: Analysing the diagnostic accuracy of ^99mTc-HYNICTOC in the workup of neuroendocrine tumours

N Chavan ¹, R Kumar ¹, S Taywade ¹

Introduction: Diagnostic workup to define the primary tumour along with regional and distant metastases in patients with NETs could be challenging in resource limited settings. We studied the role of SSTR imaging with SPECT tracer ^99mTc-HYNICTOC in the management of these patients.

Materials and Methods: We reviewed 22 ^99mTc-HYNICTOC studies performed on 21 patients (11 males & 10 females, median age 59 years, IQR 43.5-67 years) with known or suspicious NETs between January 2021 and September 2022. Lesions with uptake more than or equal to liver were taken as positive. Final disease status and diagnostic accuracies were derived based on the best valuable comparator for individual patient considering all the available clinical details including imaging (morphological & functional), HPE and follow up.

Results: Out of the total 22 scans, 13 were done for staging, 4 for restaging and 5 for suspected recurrence/surveillance. In the 13 scans done for staging, 12 had SSTR expressing primary lesions [duodenum & pancreas (4), stomach (4), Ileum (3) and rectum (1)] and 1 had non SSTR expressing primary. A total of 24 metastatic lesions were reported in 12 of the 13 staging scans with liver being the most common metastatic site. Out of the 4 scans done for restaging, 3 revealed no primary residual lesions while 1 had residual lesion. Metastases were reported in 3 of the 4 scans [liver (3) and pelvic LN (1)] all of which were SSTR expressing. The remaining 5 scans were done for suspected recurrence/ surveillance, 2 of which had recurrence. With available CT, MRI, ⁶⁸Ga-DOTANOC PET-CT & follow up, best valuable comparator was determined, and diagnostic accuracies were derived as follows: TP= 15, TN= 5, FP= 1, FN= 1. Thus, ^99m Tc-HYNICTOC scan showed an overall sensitivity of 93.7%, specificity of 83.3%, PPV of 93.7% and NPV of 83.3%. These results were in agreement with the accuracies mentioned in the available literature.

Conclusion: Both morphologic and functional imaging techniques played a complementary role in the patient management. The superiority of ⁶⁸Ga-DOTA PET-CT cannot be challenged. However, ^99m Tc-HYNICTOC may serve well in the management of NETs in settings with no Ga68-DOTA PET-CT facility.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 12: Incremental value of 18 F FDG PET CECT in breast cancer patients

Abhishek Uppal ¹, Sneha Shah ¹

Introduction: Breast cancer is amongst the most common cancers encountered in oncology imaging practice. The current NCCN consensus suggests FDG PET CT at staging in locally advanced breast cancers (LABC) i.e., T4 or N2 or N3; and in inflammatory breast cancer. We decided to look at the impact of FDG PET CT at staging breast cancer in a high-volume center in an Indian context.

Materials and Methods: Audit of FDG PET CT evaluating breast cancer from 2015-2020 was done. Staging scans were 1582 of the total 2547scans; the others were for treatment response evaluation and restaging. Correlation of FDG PET-CT findings was done with information from EMR regarding clinical stage according to conventional imaging and a note was done to look for alteration in treatment planning considering the PET findings.

Results: FDG PETCT upstaged 138 cases of clinical LABC to Oligo metastatic (OMBC), while 405 LABC were upstaged to frank metastatic disease. The 51 OMBC on CIM were found to be metastatic disease. Thus, a total of 594 cases (37.54%) disease was upstaged when evaluated with FDG PET, while in 988 (62.45%) cases there was no change in stage. The commonest site of metastatic disease identified on FDG PETCT was in bone (cortical and marrow). FDG PET had an incremental role in tracing small N2/N3 nodes leading to extension of RT field.

Conclusion: FDG PET plays a crucial role in staging breast cancer patients, it changed the intent of treatment in 37.54 % patients, either making them inoperable and making them candidates for systemic treatments or extending their RT field.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 13: Characterization of tumor thrombosis of F-18 FDG PET/CT

Datta Deepanksha ¹, Kumar Rajesh ¹

Introduction: Tumor thrombosis is important in cancer patients as it has adverse outcomes and surgical planning is more complex. Its incidence depends on types of malignancy with most common in primary renal and liver malignancies. Its identification is challenging as there are no specific clinical symptoms, nor it is restricted to any stage of malignancy. The current standard guidelines recommend Contrast Enhanced Computed Tomography (CECT) and Magnetic Resonance Imaging (CE-MRI) in distinguishing it from bland thrombus by presence of contrast enhancement and direct continuation of the primary tumor mass as characteristic of tumor thrombus. Studies suggest uptake of F-18 FDG on PET/CT as confirmation of tumor thrombus. With this retrospective analysis, we explore other metabolic parameters like SUVmax ratios of tumor thrombus, primary tumor and liver, and other imaging features that can further characterize tumor thrombus on F-18 FDG PET/CT especially on non contrast studies.

Materials and Methods: We conducted a retrospective review of FDG PET/CT studies of patients done in our department or sent for review from February 2021 to September 2022, for known malignancy and had FDG avid tumor thrombosis irrespective of contrast status. The variables recorded were as follows, SUV max (tumor thrombus), SUV max (primary malignancy), SUV max (liver), volume of the thrombus on FDG, contiguity or non contiguity of the thrombus with primary malignancy, and presence or absence of distant metastases. Correlation between these parameters was calculated using SPSS ver 2.

Results: Out of 2277 patients reviewed, 12 patients had tumor thrombus with a prevalence of 0.52%. Median age of our study population was 56.5 years (8-74 years), and 50% were males. The most common primary malignancy was lung (25%), followed by bone, renal, liver and lymphoma (16% each). The mean SUV max of tumor thrombus was 6.3. The most common vessel involved was IVC (26%), and most of them were contiguous in nature (62%).10% thrombi reached up to right atrium. 83% patients had distant metastases evident of FDG- PET/CT with most common site was lung-pleura (60%). Significant correlation was found between SUVmax of tumor and thrombus, indicating similar biological origin. There was no significant correlation noted between the volume and metabolic activity of the tumor thrombus.

Conclusion: Tumor thrombus is an aggressive feature of any malignancy, and is usually associated with distant metastases at the time of presentation. In cases where intravenous contrast cannot be administered, F-18 FDG PET/CT can still detect tumor thrombosis with metabolic activity similar to the primary tumor. Further in any case of suspected malignancy where intravascular metabolic activity is more than liver, possibility of tumor thrombus should be considered.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 14: In-vitro labelling of ¹⁷⁷Lu FAPI-46, an institutional experience

J P Kumar ¹, Shukla Varun ¹, Tayal Sachin ¹, Chauhan Ravi ¹, Chauhan Manoj ¹, M V Manikandan ¹

Introduction: Fibroblast activation protein (FAP) is a human enzyme that shows increased expression in the stroma of a variety of malignancies. Specific fibroblast activation protein (FAPI) inhibitors, labelled with different radionuclides, are being evaluated for the diagnosis and treatment of different tumours. With Theranostics in mind, we have tried to label Lutetium Chloride (¹⁷⁷LuCl₃) with FAPI-46 and establish a pair of Theranostics for desmoplastic lesions.

Materials and Methods: The manual labelling was carried out on a non-carrier added (NCA) Lutetium Chloride (¹⁷⁷LuCl₃) and quality control checked with the help of ITLC. A minimum of 25 μg of ligand/inhibitor was used for labelling, with 25mCi Lutetium Chloride (¹⁷⁷LuCl₃). The whole process was done keeping following safety measures to avoid contamination and exposure received during preparation recorded with calibrated pocket dosimeter.

Results: The in-vitro labelling process was successful as evident on instant thin layer chromatography. The whole process of labelling takes on an average of 35 minutes and the exposure during whole preparation was 3-4μSv as measured with the help of calibrated pocket dosimeter. ITLC showed labelling to be >95% in the initial trials.

Conclusion: As the initial results are promising, we wish to conduct more trials with varying parameters to help establish it for in-vivo trials/clinical usage.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 15: PSMA PET/CT for staging: The Will Rogers Phenomenon

Y Khandelwal ¹, B Jain ¹, M Ora ¹, S Gambhir ¹

Introduction: Few studies have suggested increased PSMA PET/CT utilization in the initial work-up of prostate cancer and are a suitable replacement for conventional imaging. Improvement in the prognosis of patient groups due to stage/reclassification is called the Will Rogers phenomenon. Stage migration occurs when changes in technology or algorithms reclassify a disease. Ultimately, survival in the healthier patient group improves as, the less healthy patients have been eliminated from the group by upstaging their disease. The less healthy group also has better survival, as the patients can enter the group earlier in their disease process. Accurate staging of patients suitable for radical treatment may significantly change the treatment management. We used a validated risk calculator to quantify the association of initial PSMA PET/CT use with the risk of tumor upstaging and compare it with the percentage of patients getting upstaged when PSMA PET/CT was performed in the high-risk prostate cancer patient.

Materials and Methods: In this retrospective analysis, the UCLA PSMA Risk Calculator, a validated nomogram for calculating the likelihood of upstaging on ⁶⁸Ga-PSMA PET, was applied to patientswho underwent PSMA PET/CT at initial staging with high-risk prostate cancer. Nomogram inputs were extracted from the database, consisting of clinical T stage, prostate-specific antigen (PSA) level, Gleason grade group, and percentage of positive cores on systematic biopsy. The median (IQR) risk (as a percentage) of PSMA PET upstaging probability was then calculated along with changes in nomogram inputs over time. The median (IQR) of PSMA PET upstaging in terms of lymph node staging and distant metastatic staging was evaluated from PSMA PET/CT. A total of 50 patient was included. Statistical analysis was performed in SPSS.

Results: The median age of patients was 65 years, the median PSA level was 32 ng/ml, the median percentage of positive cores was 40%, and Gleason grade groups were 4 and 4 in the patients. The median risk of nodal upstaging was 10%, and distant metastasis was 7% using UCLA PSMA Risk Calculator. Out of 50 patients, 50% had nodal metastasis, and 20% had distant metastasis on PSMA PET/CT. While upstaging may be secondary to nodal or distant metastatic findings on PSMA PET, the risk of nodal upstaging, in particular, may affect the decision between surgery and radiation. Therefore, with an increasing chance of nodal upstaging, the immediate impact of stage migration from PSMA PET may alter treatment decisions in many patients with high-risk prostate cancer.

Conclusion: This study highlights the potential prognostic value of PSMA PET/CT in the initial staging of prostate cancer patients, which adds to its well-established diagnostic accuracy, reinforcing that it should be routinely used alternatively to conventional imaging methods in high-risk prostate cancer patients.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 16: Fully automatic synthesis of ⁶⁸Ga-EDTA and its quality control for PET based glomerular filtration rate

Ravi Kumar Chauhan ¹, Varun Shukla ¹, M V Manikandan ¹, Jennit Ittiachan ¹, JayPrakash Kumar ¹, Uddeshya Jha ¹, Manoj Chauhan ¹, Ajay Rajbhar ¹, Sachin Tayal ¹, Santosh Kumar Gupta ¹

Introduction: The determination of the glomerular filtration rate (GFR) is decisive for a variety of clinical issues and it is very important to monitor the renal function in case of radionuclide therapy patients. Renal scintigraphy using ^99mTc-DTPA allows combined acquisition of renograms and GFR. Now a days, latest PET tracer ⁶⁸Ga-EDTA with dynamic PET imaging may be used and it is non-invasively and more accurate procedure to estimate the GFR by compartmental kinetic modelling. Aim of study was to optimise the automatic synthesis of ⁶⁸Ga-EDTA and its quality quality control for higher yield.

Methods: EDTA was purchased from Finar limited. Three Different Molarity such as 0.125M, 0.25M and 0.5M of EDTA were prepared by adding 2.3265g, 4.653g and 9.306g of anhydrous EDTA in 50 ml of ultrapure water. 0.1 ml of each reconstituted different Molarity of EDTA were mixed with 0.9 ml of 0.1M Sodium acetate buffer in automatic synthesizer separately and the final product was mixed with ⁶⁸GaCl₃ which was eluted from a ⁶⁸Ge/⁶⁸Ga-generator (ITG, Germany) with 0.05M HCL as the eluent. The final product was incubated for 10 minutes at room temperature. Radiochemical purity (RCP) of final product was quantitatively analyzed by TLC Scanner. Thin-layer chromatography-silica gel (TLC-SG) plates was used as a stationary phase and it was developed with a 0.1 M Tri-Sodium Citrate as a mobile phase.

Results: Quality of 10 batches of ⁶⁸Ga-EDTA with three different molarity of EDTA was evaluated. Average RCP of labelled ⁶⁸Ga-EDTA was 99.54 %, 87.16% and 78.75% with 0.25M EDTA, 0.125M EDTA and 0.5M EDTA respectively. Rf of ⁶⁸Ga-EDTA was 0.106, 0.114 and 0.126 with 0.25M EDTA, 0.125M EDTA and 0.5M EDTA respectively.

Conclusion: The high radiochemical yield (99.54%) and purity showed this method is a reliable tool for the automatic synthesis of ⁶⁸Ga-EDTA and to be used for the PET based GFR estimation with high resolution.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 17: Treatment response evaluation using texture analysis on 18-fluorodeoxyglucose positron-emission tomography/computed tomography in patients with locally advanced breast cancer

Navneet Singh ¹, Geetanjali Arora ¹, Anil Kumar Pandey ¹, Rakesh Kumar ¹

Introduction: The objectives of this study were to (1) utilize the ability of texture analysis to evaluate the treatment response in patients with locally advanced breast cancer (LABC) and overall survival (OS) and (2) to compare the result with PET/CT parameters.

Materials and Methods: We retrospectively analyzed 57 patients with histopathologically proven LABC. 18-fluorodeoxyglucose positron-emission tomography/computed tomography (18F FDG PET/CT) scan was performed at the baseline and after 6-12 cycles of chemotherapy. Thirteen haralick texture features were derived from the baseline scan. An independent nuclear medicine physician evaluated the 18F FDG PET/CT parameters in the baseline scan. Mann Whitney U test & independent T-test were performed to determine the significance of the difference in the mean value of texture parameters & PET/CT parameters. Cox- regression & Kaplan- Meier tests were applied for survival analysis.

Results: Mean age of patients was (46.07 ± 1.46 years). Based upon the clinical follow-up, out of 57 patients, 39 patients were categorized as responders & 18 patients as non - responders. Out of the thirteen texture parameters, two of the texture parameters: sum average (V6) with p = 0.071 & sum variance (V7) with p= 0.069 were found to approach a statistically significant level. Responders had higher values of TLG AND MTV than non-responders. Kaplan-Meier test showed the trend for the OS of the patients with the higher value of MTV & TLG observed with patients who died than in the patients who survived. No texture parameters & PET parameters were significant to differentiate between responders and non-responders and also didn't significant in differentiating between the two survival groups (died and alive).

Conclusion: We concluded that two of the texture parameters: sum average (V6) and sum variance (V7) that were approaching significant may have role in predicting treatment response if studied in a larger sample size with a more homogenous patient population.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 18: Role of ⁶⁸Ga PSMA PET/CT in adenocarcinoma prostate – Initial experiences from state of Jharkhand

Abhishek Kumar ¹, Bhola Kumar ¹, G Sonai Muthu ¹, Sujata Mitra ¹

Introduction: PSMA PET/CT is an established modality of choice for staging and response evaluation in patients with prostate cancer. Portability of Ge68/Ga68 generator and feasibility of radiolabelling PSMA with ⁶⁸Ga isotope makes ⁶⁸Ga- PSMA PET/CT an ideal and readily available modality at remote centres in India. We are the first PET-CT centre in state of Jharkhand, India and present our initial experience with ⁶⁸Ga PSMA PET/CT in patients with adenocarcinoma prostate.

Materials and Methods: We retrospectively evaluated 154 patients with diagnosis of prostate cancer who underwent ⁶⁸Ga-PSMA PET/CT at our centre over a period of approximately 18 months. 148 patients were referred for PSMA PET/CT with histopathological diagnosis of adenocarcinoma prostate, rest 6 patients were sent for evaluation on basis of extensive skeletal sclerotic lesions and raised PSA levels. These patients underwent PET/CT for either baseline staging or response evaluation to therapy. Overall disease burden and response to therapy were correlated with serum PSA levels. Total of 186 PSMA PET/CT scans were analysed. PSMA PET/CT results were compared with conventional CECT and ^99mTc – MDP bone scan whenever available.

Results: ⁶⁸Ga-PSMA PET/CT done for baseline staging detected extraprostatic disease in 65% of cases. Sensitivity of ⁶⁸Ga68-PSMA at baseline with histopathological diagnosis was 95%. In 12 patients with surgical castration, PSMA PET/CT demonstrated progression of disease. In patients with metastatic bone disease PSMA PET/CT detected more number of lesions in comparison to conventional CT and ^99mTc – MDP bone scan. PSMA PET CT was able to detect lesions which were not apparent on bone scan or CT. ⁶⁸Ga-PSMA even demonstrated metastatic lesions in patients with low PSA levels.

Conclusion: ⁶⁸Ga-PSMA PET/CT is a modality of choice for staging, restaging and response evaluation to therapy. Whenever available it should be the investigation of choice in patients with biochemical relapse. It is also an optimal imaging modality to assess disease burden in metastatic disease and guide selection of patients for treatment with PRRT.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 19: Role of FDG PET-CT in the restaging of male breast cancer

Sneha Prakash ¹, Rakesh Kumar ¹, K V Sivasankar ¹, Kh Bangkim Chandra ¹, Madhavi Tripathi ¹, C S Bal ¹

Introduction: The disease biology of male breast is distinct from that of female breast cancer. However, due to limited and inadequate research in male breast cancer, the diagnostic approaches and treatments in female breast cancer are generally extrapolated to male breast cancer as well. Restaging for local recurrence and distant metastasis is accepted as one of the appropriate use criteria for FDG PET-CT in female breast cancer. We undertook this study to assess the role of FDG PET-CT in restaging of male breast cancer- to detect suspected local recurrence and/or distant metastasis.

Materials and Methods: We systematically analysed the database of our institute to identify male patients with histopathologically proven breast cancer referred for an FDG PET-CT from the year 2017 to 2021 in view of suspected local recurrence and/or suspected distant metastasis for restaging. Ten such patients were identified and were retrospectively included in this study. The scans were independently read by two experienced nuclear medicine physicians and significant findings were correlated with biopsy results, further workup and/or patient follow-up.

Results: Among the 10 patients (age range: 35 to 77 years, mean: 56 years), 5 patents had a PET-CT scan done twice in the four year duration to detect recurrence while the other 5 patients underwent PET-CT once to detect recurrence. Out of the total 15 FDG PET-CT scans done for restaging, 6 (40%) were negative for recurrence, 6 (40%) were positive and 3 were equivocal (20%) with suspicious findings that were advised for follow up. Two out of six negative scans (33%) turned positive for recurrence on follow-up PET-CT which was done 1 year later for one patient and 3 years later for the other patient. Among the positive scans for recurrence, local recurrence in chest wall was detected in 2 out of 6 patients (33%). Lymph nodal recurrence was detected in 3/6 patients (50%) among whom, 2 (67%) were positive for ipsilateral axillary lymph nodal recurrence while 1 (33%) was positive for ipsilateral internal mammary lymph nodal recurrence. Recurrent disease due to newly detected distant metastasis were found in three sites- lungs, skeleton and liver. Pulmonary metastasis was detected in 3 out of 6 patients (50%), skeletal metastasis was detected in 3 out of 6 patients (50%) and hepatic metastasis was detected in 1 out of 6 patients (17%).

Conclusion: FDG PET-CT seems to be a useful imaging method for restaging in male breast cancer. PET-CT is helpful in detecting loco-regional lymph nodes as well as distant sites in these patients.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 20: Head-to-head comparison between 68Ga-pentixafor and 18F-FDG positron emission tomography with computed tomography in diffuse large B cell lymphoma

P Pradap ¹, Harish Goyal ¹, Prashanth Ganesan ¹, Dhanapathi Halanaik ¹

Introduction: Positron emission tomography with computed tomography (PET/CT) using the standard radiotracer [18F] FDG (2-deoxy-2- [18F]fluoro-D-glucose) is the most recommended method for imaging patients with diffuse large B cell lymphoma (DLBCL). However, there is significant over-expression of the CXCR4 chemokine receptor in the DLBCL and a marker of disease aggressiveness. Furthermore, it has the potential for theranostics and CXCR4-targeted radionuclide therapy. We evaluated in vivo expression of the CXCR4 chemokine receptor using novel tracer 68Ga-Pentixafor PET/CT in DLBCL patients and compared it to 18F-FDG PET/CT.

Materials and Methods: Pathologically proven treatment-naive patients with Diffuse large B- Cell lymphoma were enrolled in this prospective study. The institute's ethics committee approved this study and informed consent was obtained from all the patients. Twenty patients (12 Males; 8 Females, Median age 55 years, Range 25- 73 years) underwent 18F-FDG PET/CT and 68Ga-Pentixafor PET/CT maximum time interval between the two studies being 5 days. PET/CT was evaluated separately for 23 anatomic regions (12 lymph node stations and 11 organs/tissues). Concordance between 18F-FDG PET/CT and 68Ga-Pentixafor PET/CT was assessed based on standard Lugano's staging. Cohen's Kappa agreement test analyzed the agreement. Semi-Quantitative parameters were calculated, including the standardized uptake value (SUVmax) and target-to-background ratios (TBRblood).

Results: Lymphoma involvement was detected by both 18F-FDG PET/CT and 68Ga-Pentixafor PET/CT in a total of 114 anatomic regions. In this 16/114 extranodal sites are noted (excluding spleen & bone marrow lesions). In comparison, 18F FDG PET/CT detected additionally three extranodal sites, and 68Ga-Pentixafor detected bone marrow involvement in 2 patients (Biopsy proven). The mean SUVmax value in 68Ga-Pentixafor PET/CT is 1.38, 95% CI (0.91, 1.8) and 18F-FDG PET/CT is 2.68, 95% CI (1.59, 3.7). The mean TBR in Pentixafor is 7.4, 95% CI (5.533, 9.267) and in 18F-FDG is 15.53, 95% CI (11.0729, 19.9871). Discordance of staging has been found in 2/20 patients due to the additional detection of bone marrow involvement by Pentixafor and extranodal detection by 18F-FDG PET/CT. Even though high mean SUVmax and TBR in 18F-FDG PET/CT, overall staging showed statistically significant agreement between 18F-FDG and 68Ga-Pentixafor PET/CT (Kappa factor- 0.83, 90% of agreement).

Conclusion: 68Ga-Pentixafor PET/CT showed good concordance and comparable diagnostic performance to 18F-FDG PET/CT for baseline staging in patients with DLBCL.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 21: Modified deferoxamine derivatives as chelator with ⁸⁹Zr and its application as PET imaging agent

Anjli Shrivastav ¹, Manish Dixit ¹, Sarita Kumari ¹, Sanjay Gambhir ¹

Introduction: Deferoxamine B, acyclic chelator bearing three hydroxamate groups, is the most widely used chelator for labeling of Zirconium-89 to specified monoclonal antibody. Computational studies strongly suggest that DFO forms a hexacoordinate complex with Zr⁴⁺ in which the metal center is coordinated to the three neutral and three anionic oxygen donors of the ligand as well as two exogenous water ligands. The ligand stably coordinates the Zr⁴⁺cation quickly and cleanly at room temperature and biologically pH levels, resulting ⁸⁹Zr-DFO complex Despite the remarkable developments of the clinical ⁸⁹Zr-immuno-PET, chemical species and stability constants of the Zr-DFO complexes remain controversial. The in vivo behavior of radioimmunoconjugates employing the ⁸⁹Zr-DFO conjugation scaffold has generally been excellent. However, in some cases, imaging and acute bio-distribution studies have revealed elevated activity levels in the bones of rodents that suggest that the osteophilic⁸⁹Zr⁴⁺cation is released from the chelator in vivo and subsequently mineralizes in the bone. Recently, a number of investigations into the development of novel ⁸⁹Zr⁴⁺chelators particularly ligands with eight oxygen donors have appeared in the literature. Easily the most common strategy, however, has been the use of an isothiocyanate-bearing derivative of DFO, DFO-NCS. Our group explored the chemistry of preparing these modified DFO and their bio-conjugation with mAb. We find excellent yield of modified chelators and characterize them. These modified chealors were explored to bio-conjugate with mAb and further radiolabelled with ⁸⁹Zr, and were performed both in-vitro stability and in-vivo studies.

Materials and Methods: Produced ⁸⁹Zr via ⁸⁹Y (p, n)⁸⁹Zr was purified using Hydroxamate based solid phase media and isolated in the form of ⁸⁹Zr-oxalate. The ⁸⁹Zr-oxalate was chelated with modified DFO-linkers (DFO-Squaric acid, DFO*-NCS, p-SCN-Bn- DFO) and characterized by different battery of quality assurance tests and then conjugated with mAb and purified using size exclusion column (PD10 column). The radiolabelled mAb's quality assurance was performed and its in-vitro stability and chelation stability was analyzed. The in-vivo studies over healthy rats were performed.

Results: The Squaric acid, and isothyocynate as modified linker to DFO has been explored and chemistry of preparing these DFO derivatives were optimized. It shows excellent chemical characteristic and yield. Further bio-conjugation with Rituxmab was optimized and explore as PET immune agents.

Conclusion: Themodified DFO Chelator was synthesized and bio-conjugated with mAb and radiolabelled with ⁸⁹Zr as PET immune agents.

Acknowledgement: This research work has been funded by extramural grant IAEA Austria Vienna, (CRP-F22071).

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 22: To study correlation between low risk prostate cancers/intermediate risk prostate cancers/high risk prostate cancers and SUVmax values on 68-Ga PSMA PET CT

P Mangale ¹, A Agrawal ¹, V Rangarajan ¹

Aim: The study aims to see the correlation between Standardized Uptake Value (Max) of prostatic lesions in relation with risk stratification of prostate cancers.

Materials and Methods: Initial staging 68-Ga PSMA PET CT scans of 286 patients with prostate cancers (Low Risk- 11, Intermediate Risk- 63, High Risk- 212) were assessed. SUVmax values of the prostatic lesions were noted. Gleason's score as per the respective histopathological reports available from Electronic Medical Records was recorded. Mean and median SUVmax values of respective categories were obtained. Kruskal Wallis test was applied to the given study data.

Results: The mean SUVmax in low risk / intermediate risk / high risk prostate cancers was found to be 15.07, 18.80 and 31.50 respectively. The median SUVmax across the categories was 8.78, 18.45 and 26.06 respectively. The median rank in low risk category was 69.09, in intermediate risk category was 104.95 and high risk category was 158.82. As per Kruskal Wallis test, difference between group SUVmax values across low / intermediate / high risk prostate cancer categories is statistically significant.

Conclusion: A positive correlation was found between the SUVmax values of prostatic lesions and the risk category of the patient, a higher median SUVmax value being observed in high risk prostate cancers cases and a lower median SUVmax value being observed in low risk prostate cancer cases. The SUVmax value of prostatic primary lesion can be used as a predictive indicator of the risk category of the individual before a 12 core prostate biopsy.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 23: Correlation of various quantitative parameters on FDG PET-CT in primary brain tumors with histopathological grades

T Ravichandran ¹, R Kumar ¹, S K Taywade ¹

Introduction: Brain tumors are important cause of mortality and morbidity in children (30%) and young adults (20%). FDG PET detects metabolic activity of tumor, thereby aiding in complete tumor resection and also detection of tumor recurrence. FDG PET may have independent prognostic value in brain tumors. This study evaluated various quantitative parameters on FDG PET-CT and their association with postoperative histopathological grading in patients with brain tumors.

Materials and Methods: Patients with clinically and/or radiologically suspected primary brain tumors were studied prospectively. Total 30 patients (23-males & 7-females) who underwent FDG PET-CT during February2021-June 2022 and subsequent tumor excision were included. The mean age of patients included was 37.3years (range 8-73years). FDG PET-CT images were acquired post 45minutes of intravenous 0.10-0.14mCi per kg of body weight of F18-FDG administration. Image analysis done by qualitative and quantitative methods. Various quantitative parameters in volume of interest (VOI) like SUVmax, mean & peak and relative parameters based on ratio of SUVs like tumor to white matter (T/W), tumor to grey matter (T/G), tumor to basal ganglia (T/B), tumor to cerebellum (T/C) and tumor to temporal lobe (T/T) were obtained and correlated with histological findings. Postoperative histopathological finding was taken as reference standard.

Results: Out of 30 patients who underwent surgery, 26 patients showed primary brain tumors in histopathology. 2 patients with benign lesions (epidermoid cysts), 1 patient with Ewing's sarcoma & another with lymphoma were excluded. All 26 patients showed abnormal FDG uptake in primary brain tumor region in the form of hypo, heterogeneous or hyper metabolism with corresponding CT abnormalities. Distribution of tumor histopathological grades and quantitative parameters were analyzed. The correlation coefficients were calculated using Pearson method. Several parameters SUVmax, SUVmean, SUVpeak and relative quantitative parameters based on SUV showed moderate correlation with WHO histopathological grades. Absolute parameter, SUVpeak and relative parameters, tumor to greymatter (T/G) & tumor to temporal lobe regions (T/T) ratios based on SUVpeak showed good correlation among the parameters in the given table.

Quantitative parameters	Correlation coefficients (r)
Quantitative parameters	SUVmax	SUVmean	SUVpeak
SUV	0.48	0.52	0.61
Ratios
T/G	0.63	0.58	0.66
T/W	0.52	0.57	0.61
T/B	0.56	0.57	0.59
T/C	0.61	0.59	0.65
T/T	0.62	0.61	0.66

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T/W: Tumor to white matter, T/G: Tumor to grey matter, T/B: Tumor to basal ganglia, T/C: Tumor to grey matter, T/T: Tumor to temporal lobe regions, SUV: Standardized uptake value

Conclusion: The tumor grade is known prognostic factor in primary brain tumor patients. This study concludes that the quantitative parameters can expand the utility of FDG PET-CT beyond localization & metabolic assessment as well as in preoperative grading of brain tumors. Further studies with large sample size would be required for the validation of these quantitative parameters.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 24: Correlation between 68-Gallium-PSMA PET/CT and multiparametric MRI in evaluation of primary prostate carcinoma

S Rajkotia ¹, V Rangarajan ¹, A Agarwal ¹, A Katdare ¹, P Popat ¹, N Sable ¹, S Menon ¹

Introduction: Prostate cancer is the second common cancer in men worldwide. The main diagnostic workup for prostate cancer includes Digital rectal examination, assessing serum concentration of Prostate Specific Antigen (PSA) and trans rectal ultrasonography (TRUS) guided biopsy for histological confirmation. Multi parametric MRI is considered standard for local staging of prostate cancer and also helps to guide biopsy by accurately localizing lesions. 68-Gallium-PSMA PET/CT is an emerging modality for local and systemic staging of prostate cancer and its utility to target biopsy is also being explored. Hence this study aims to compare the diagnostic accuracy of 68-Gallium-PSMA PET/CT and multipara metric MRI for intra prostatic localization of prostate cancer foci.

Materials and Methods: 20 treatment naïve patients with biopsy proven prostate cancer were retrospectively selected. All patients had undergone 68-Gallium-PSMA PET/CT, multipara metric MRI and 12 core TRUS guided biopsy. 68-Gallium-PSMA PET/CT, multipara metric MRI were independently interpreted by a nuclear medicine physician and a radiologist who were unaware of the result of the other modality. 12 core TRUS guided biopsy results were noted.12 sector map of prostate was adapted to correlate imaging findings with 12 core biopsy results. Diagnostic accuracy (sensitivity, specificity, positive predictive value and negative predictive value) of 68-Gallium-PSMA PET/CT, multipara metric MRI for was compared for intra prostatic localization with histopathology being gold standard.

Results: 240 sectors (n=20) were analyzed on 68-Gallium-PSMA PET/CT and multipara metric MRI respectively. Diagnostic performance of both the modalities was assessed one on one using 12 core biopsy results as gold standard. The sensitivity, specificity, PPV, NPV of PSMA PET/CT and multipara metric MRI were 62%, 61%, 59%, 64% and 56%, 77%, 68%, 66% respectively.

Conclusion: The diagnostic accuracy of multipara metric MRI was found to be slightly greater than 68-Gallium-PSMA PET/CT in the intra prostatic localization of cancer foci.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 25: Early response assessment with FDG PET-CT, post neoadjuvant chemo-radiation in patients of carcinoma oesophagus: Unseen challenges in interpretation

R Pandey ¹, S Taywade ¹, R Kumar ¹

Introduction: Time interval between neoadjuvant chemo-radiation (NACT-RT) and surgery is critical in management of patients with carcinoma oesophagus. Late surgery increases the chances of pathological complete response, however it is associated with intra-operative difficulty in dissections due to radiation induced dense fibrosis. Thus, early surgery is preferred by some surgeons. On the other hand FDG PET-CT is recommended post 8-12 weeks of radiotherapy in order to avoid inflammation related false positivity. So, early FDG PET-CT needs different approach in interpretation. We evaluated various metabolic response patterns in patients with carcinoma oesophagus who underwent early PET-CT post NACT-RT.

Materials and Methods: We reviewed FDG PET-CT studies of 109 patients with carcinoma oesophagus who underwent FDG PET-CT in department of Nuclear Medicine between February 2020 to September 2022. Total 16 patients underwent FDG PET-CT within 90 days of receiving RT were analysed retrospectively.

Results: The mean age of the 16 patients who underwent early PET-CT post RT was 50.81 years. There were 10 females and 6 males. The average duration between the RT and PET-CT was 44.18 days. Baseline PET-CT was available for 9/16 patients. 5/16 patients had focal FDG avid lesions pointing towards residual disease and their post-operative histopathological examination (HPE) revealed significant residual tumor cells (4-pT3 and 1-pT2). Amongst 11 patients with PET-CT picture of only post-treatment changes, 2 had post-operative HPE showing residual disease (1-pT3 & 1-pT2). Scan of patient with pT3 histopathology showed metabolism along the length of oesophagus with a focal hypermetabolic nodularity and in the other, it was a false negative finding. Among the remaining 9/11, 7 had post-operative HPE showing only post treatment changes with no evidence of tumor, 2 didn't undergo surgery (1 is on follow-up considering the age & comorbidities, 1-patient is scheduled for surgery). The characteristics of post RT changes include: (1) Significant reduction in size & metabolism of primary lesion in oesophagus and previously seen metastatic lymph nodes (2) Heterogeneous or mild diffuse uptake in oesophagus in the region of RT. (3) No significant thickening or mild diffuse thickening in the oesophagus (4) The uptake is more along the intraluminal/mucosal surface (5) There is increase in extent of FDG uptake in the region beyond the the known primary site in oesophagus.

Conclusion: Tumor metabolic activity post treatment strongly correlates with histopathological response. With studies showing benefits of early surgery post CTRT in carcinoma oesophagus, there is a need for standardization of the optimal timing for response evaluation by FDG PET-CT as well as define the metabolic response criteria. This study concludes that the scans done in early setting needs a careful evaluation with different interpretation approach to reduce the false positive rate due to radiation induced inflammation.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 26: Effectiveness of metabolic-volumetric indices of 68-Ga DOTANOC positron emission tomography/computed tomography for the evaluation of treatment response in gastroenteropancreatic neuroendocrine tumors

Y Yadav ¹, A Puranik ¹, V Rangarajan ¹, N Purandare ¹

Introduction: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs), also known as carcinoids and islet cell tumors, derived from neuroendocrine cells that can occur anywhere along the gastrointestinal tract and comprise a heterogeneous family of neoplasms with a wide and complex spectrum of clinical behaviour. GEP-NETs have traditionally been divided into (i) Foregut (ii) Midgut (iii) Hindgut. Neuroendocrine tumour may grow slowly or aggressively and spread to other parts of the body. GEP NETs are often metastatic at presentation. Many people do not develop symptoms and the tumour is detected incidentally. When symptoms occur, they can vary based on the location of the tumour. In rare cases, skin flushing or fluctuating blood sugar levels may occur. Treatment depends on the type of tumour and it has two objectives i.e. Removal of tumor and relief in symptoms of excessive hormone production. Survival of patients with GEP-NETs depends on stage and histology. Ga-68-DOTATATE PET/CT is the imaging modality of choice for staging and response evaluation for well-differentiated NETs. Somatostatin receptor expression forms the basis of treatment, with Octreotide LAR being the preferred first-line treatment. Current standard of care is to use Peptide Receptor Radionuclide Therapy (PRRT) with Lu-177-DOTATATE for patients with progression on LAR.

Materials and Methods: It was retrospective, observational study and was done in 25 GEP NETs patients. All patient received at least two cycles of DOTAPRRT therapy and their baseline, post 2 cycles and 4 cycles DOTANOC PET/CT scans were available. Krening's score; comparing single lesion SUVmax of the primary tumor and metastatic lesion; metabolic tumor volume of primary and metastatic lesions, if extensive metastatic then 5 target lesion (maximum 2 lesions/organ); SUV mean of liver; all these variables were assessed by using Wilcox on signed rank test. A p value less than 0.05, concluded as statistically difference.

Results: 16.6% of patients showed statically significant MTV response in metastatic lesion after second and 33.2% showed after fourth cycle 177- Lu DOTAPRRT therapy. 40% patients showed statically significant response in metastatic nodes in form of MTV only after fourth cycle. Median PFS after four cycles was 12 months. Out of 25 patients only 8% showed CMR, 32%-PMR, 32%-SMD & PMD 28% after two cycles of PRRT.

Conclusion: Thus, Lu-177-DOTATATE PRRT is effective treatment in treatment of metastatic lesions in GEPNETs.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 27: Comparison of ⁶⁸Ga-PSMA and ¹⁸F-FDG PET/CT in metastatic workup of renal cell carcinoma

Saurav Jha ¹, Naresh Kumar ¹, Shamim Ahmed Shamim ¹, Atul Batra ¹, Ranjit Kumar Sahoo ¹, Prabhjot Singh ², Brusabhanu Nayak ², Chandan J Das ³, Seema Kaushal ⁴, Geetanjali Arora ¹, C S Bal ¹

Introduction: ¹⁸F-FDG PET/CT is not currently recommended for the diagnosis and staging of RCC based on updated national and international guideline, however, the role of PET/CT in staging and metastatic workup in RCC is evolving. In general, ¹⁸F-FDG PET/CT is used in high-risk RCC patients with better sensitivity for detecting distant metastasis, providing anatomic and metabolic information. PSMA is expressed in the endothelial cells within the neo-vasculature of various solid malignant tumors including clear cell RCC. Few case reports showed more accurate staging for metastatic RCC with PSMA. Therefore, present study aimed to compare the role of ¹⁸F-FDG and ⁶⁸Ga-PSMA in metastatic work-up RCC.

Materials and Methods: Patients with histopathological and/or radiological confirmed RCC were intravenously injected with 10mCi of ¹⁸F-FDG and 3-5mCi of ⁶⁸Ga-PSMA. Images were acquired at 60 & 45 mins post-injection for ¹⁸F-FDG and ⁶⁸Ga-PSMA respectively, on dedicated PET/CT scanners. Acquired whole body PET/CTs were analysed both visually and quantitatively by two experienced nuclear medicine physicians.

Results: Twenty (20) patients (16 male, 4 female) with mean age 56.8± 12.5 years of known RCC underwent ¹⁸F-FDG and ⁶⁸Ga-PSMA PET/CT within atleast 1 week. Of 20 patients, 16 patients had clear cell RCC, while 4 had papillary cell RCC. Three out of sixteen (3/16) patients with clear cell RCC patients and 2/4 with papillary cell RCC had no lesion uptake in PSMA PET/CT. Total 245 lesion were positive in FDG PET/CT, while 138 lesions were seen positive on PSMA PET/CT. Of 20 patients, 5 patients showed concordant lesions and 15 patients showed discordant lesions in ¹⁸F-FDG and PSMA. Of 15 patients with discordant lesions, 12 patients showed more FDG avid lesions than PSMA and 3 patient showed more PSMA expression lesions than FDG avid lesions. Of 3 patients with high PSMA expression, 1 had additional sub-hepatic peritoneal lesion which was later confirmed on FNAC, 1 patient with brain mets were better appreciated with PSMA than FDG PET/CT and in 1 patient PSMA expression was helpful to differentiate between infective and metastatic mediastinal lymph node which was later confirmed by histopathological examination.

Conclusions: ⁶⁸Ga- PSMA may be useful as an additional modality to FDG PET/CT for metastatic work in RCC patients and in near future it may be used as surrogate for theranostic modality in patients with limited therapeutic options particularly when high tumor to background ratio (>1) on PSMA PET/CT.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 28: Incidentally detected adnexal lesions in primary breast carcinoma: Is delayed PET/CT beneficial?

T Gupta ¹, R Kumar ¹, S Taywade ¹

Introduction: Etiologies of incidental adnexal lesions in primary breast cancer includes physiological, benign or malignant cause. However nearly three fourth of these lesions turn out to be benign. As physiological uptake of FDG is noted in ovary as well as benign lesions, it may become difficult to assess their malignant potential. Here we are evaluating the role of FDG-PET/CT in cases of incidental adnexal lesions in primary breast lesions, and if delayed PET/CT is helpful.

Materials and Methods: We have retrospectively evaluated 300 18 F-FDG PET/CT studies including staging and follow up scans for female patients (Median age=51, range=20-88 years) with primary breast carcinoma. Incidental adnexal lesions were detected in 44 studies of 34 patients. Delayed pelvic PET-CT was done in 20 studies (110+/-50min post whole body scan acquisition and 40 mg iv Lasix injection). Lesions were divided on basis of FDG avidity, and further description SUVmax on whole body images and SUVmax on delayed images were obtained. Imaging modality was performed in 7 patients, CA-125 was done in 4 and HPE post salpingooopherectomy was available in 2 patients. Follow up PET-CT was done in 10 patients.

Results: Out of 44 lesions, 13 lesions were metabolically inactive. Delayed PET-CT was performed in 19 of 31 lesions. Out of them, 4 patients showed no change and 8 patients showed decrease in delayed SUVmax. 1 patient showed FDG avid right adnexal mass, delayed images showing decrease in SUVmax, after salpingoopherectomy, the histopathology was benign (leiomyoma). 1 patient showed bilateral adnexal lesions, with delayed SUVmax less than on whole body images, and CA-125 value of 811. In view of metastasis, bilateral salpingoopherectomy was performed which was negative for malignancy. In 2 patients other imaging modalities and CA125 were normal and on follow-up the patients are stable. Four patients showed same or decreased delayed SUVmax on follow up PET-CT, hence deemed benign. No further evaluation was done for 4 patients. 4 patients showed mild increase in SUVmax in delayed images. Other imaging modalities and/or CA 125 came normal in 3 and 1 showed no significant uptake in follow up PET-CT hence was termed as benign lesion. Three patients showed significant increase in SUVmax in delayed images. Follow up PET-CT for these patients showed persistent lesion, however further evaluation was not carried out.

Conclusion: In patients with breast cancer with an adnexal mass, the distinction between primary, metastatic or benign condition is essential for treatment. Incidental detection of lesion warrants further investigations in form of serum biomarkers and ultrasonography. Delayed PET-CT may be useful to identify benign lesions using semiquantitative parameters like SUVmax, and even mild increase in SUVmax may point towards a benign lesion than malignancy, and thus help direct investigations and further procedures for the patient, also helping in reducing unnecessary salpingooopherectomy procedures. However larger sample size studies with follow up details are required.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 29: Ensemble learning aided PET/CT to differentiate bony lesions of tuberculosis and thyroid cancer

Aditi Khurana ¹, Sumit Garg ¹, Anil Kumar Pandey ¹, Shubha G Ravindra ¹, Rakesh Kumar ¹, C S Bal ¹

Introduction: Osteolytic bony lesions could be a result of non-malignant lesions such as skeletal tuberculosis (TB) or malignant lesions namely metastasis from primary tumors, multiple myeloma (MM), lymphoma, sarcoma and primary bone tumors. In the LMIC, TB has been a diagnostic challenge for years and oncologists are expected to keep it high up in their list of differentials while staging and restaging the disease. Thyroid cancer is the 9th most common cancer world wide and bony lesions associated with Thyroid carcinoma are typically osteolytic. There is a great overlap between the metabolic representation of malignancy and TB which limits the value of FDG PET/CT in the same. Here we intend to apply Ensemble learning to determine the etiology of metabolically active bony lytic lesions and classify them into two categories viz Thyroid Cancer and Tuberculosis (TB).

Materials and Methods: 42 clinically diagnosed/ histopathologically (HPE) proven cases of bone TB and 46 biopsy proven cases of Thyroid cancer who underwent PET/CT at our institute were randomly selected from a retrospective database ranging from January 2017 to July 2022. The PET/CT images were displayed at the default pre-set parameters (40% SUV max threshold). Trans-axial image sections with the largest active bony lesion were selected and exported in JPEG format. The segmented image (mask) was converted into a gray level image (binary) and the intensity of each pixel was quantized into number of bins equal to 32. The distance between the reference pixel and it neighbour was kept 1 pixel in the horizontal direction at an angle of zero degree for creating a gray level co-occurrence matrix (GLCM). Machine training was done on training data (80%). During training 10-fold cross validation technique was used. An exclusive part of the total data (20%) was used as test data set. Accuracies were reported as median and range.

Results: A total of 26 Haralicks texture features were computed from the GLCM matrix that quantify pixel (i.e. lesion) texture. The SvmRadial algorithm was used for training the machine. All tests were performed using R statistical programming language. Packages used were Caret and EBImage. The median accuracy on using SvmRadial as a classifier run 30 times on training data and test data was 70% (23%- 77%) and 53% (29%-76%) respectively.

Conclusion: Ensemble learning has an established role in imaging & diagnostics and here we successfully demonstrate its utility for differentiating bony lesions of Thyroid cancer and TB. We intend to promote this model as a simple and easy to use Artificial Intelligence based tool which can be integrated into routine clinical practice.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 30: Initial experience of fully automated radiosynthesis and biodistribution of ¹⁸F-FES

Beena Chaudhary ¹, Aparna Mahalik ¹, Parveen Kumar ¹, Madhavi Tripathi ¹, Ajay Gogia ¹, Rakesh Kumar ¹, C S Bal ¹

Introduction: Breast cancer is the most common malignancy in women and the second leading cause of cancer death in women.16 alpha-[¹⁸F] fluoroestradiol (¹⁸F-FES) is an important tracer in nuclear medicine as an estrogen receptor (ER) ligand for investigating hormone positive primary and metastatic breast cancers. We share our initial experience of fully automated radiosynthesis and biodistribution of ¹⁸F-FES in patients with metastatic ER positive breast cancer.

Materials and Methods: ¹⁸F was produced in an 11 MeVmedical cyclotron (RDS Eclipse) and transferred to the automated synthesis module (Neptis Synthesizer) for FES labeling. The hardware cassette and ready to use reagent kit for labeling was obtained from ABX (Germany). Cyclic sulfate precursor MMSE was radiolabeled via nucleophilic ¹⁸F fluorination with 500μl 0.075M TBA-HCO₃ solution, and followed by hydrolysis step with 3ml of ethanol/sulphuric acid solution. The radiolabeled mixture was purified by the purification cartridges (C18, WAX and HLB). The purified ¹⁸F-FES compound was transferred through the alumina cartridge to the final vial containing 15ml distilled water. After production of ¹⁸F-FES, its quality control included appearance, pH, radionuclide purity and radiochemical purity which was checked before injection into patients.¹⁸F-FES, 111-222 MBq (3-6mCi) was injected intravenously into 19 patients (mean age=52.3±12.4 years). The whole-body PET/CT scan was done after 60-90 minutes interval in each case. The biodistribution of ¹⁸F-FES was evaluated visually and by measuring the SUVmean and SUVmax in liver and gall bladder inall the patients.

Results: The average radiochemical yield from 3 syntheses of ¹⁸F-FES was 10.3% (decay corrected). The overall synthesis time was 70-75 minutes. Average radiochemical purity, radionuclide purity, and pH was95%, 99.7% and 5, respectively. ¹⁸F-FES accumulation was noted in the liver, gall bladder, small intestine and the urinary system. The average SUVmean and SUVmax in liver was 10.8±4.2 and 11.7±4.3 and in gall bladder was 103.3±61.5 and 142.5±86.6, respectively.

Conclusions: Labelling of FES in a fully automated synthesis module with relatively short synthesis time, moderate radiochemical yield, and high radiochemical purity is a convenient way to produce ¹⁸F-FES for routine clinical use and has a favourable biodistribution pattern.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 31: Sentinel lymphnode biopsy in early breast cancer in 137 patients KMCH experience

Divya Velusamy ¹, K K Kamaleshwaran ¹, E Ramkumar ¹, E R Radhakrishnan ¹, Arun Pandiyan ¹, F R Kingsley ¹, A Sowmiya ¹, Ruth Rajasekar ¹, C Vinoth Kumar ¹, M Kaviya ¹, Rithika Rajkumar ¹

Introduction: The aim of this study is to find out the number of sentinel nodes seen in SPECT CT imaging and during surgery and identify false negative rate and recurrence rate in early Breast Cancer Patients undergoing Sentinel Lymph Node Biopsy (SLNB). SLNB is a minimally invasive technique to identify the sentinel axillary lymphnodes. The complications in SLND are very less compared to Axillary Lymph Node Dissection (ALND). From 2017 still now, we have identified SLNB of 137 patients with T1-T2 Early Breast Cancer with no palpable axillary lymphnodes.

Materials and Methods: Total of 137 patients with early breast cancer underwent SLNB. Average age in-between 50-60yrs, Younger is 25 and Older is 83. Tc^99m labelled colloid particles such as Nanocolloid or Human Serum Albumin in 3 insulin syringes with each (0.5-1.5mci) was injected intra-dermally in peri-areolar region. SPECT CT of chest was done on the day or before day of surgery and identified number of nodes in three level of axilla and informed to surgeons before surgery. Blue dye was also injected during surgery. Surgeon removed hot and blue nodes with the help of hand-held gamma probe and sent to frozen section biopsy. If the nodes are negative, no ALND was done, if node positive, then Surgeon will Proceed with ALND.

Results: Among 137 patients, total 250 nodes were identified in SPECT CT, only 13 patient's nodes were not identified in SPECT CT, average 2-3 nodes were identified in level I and II axilla. But in all 13 patients, hot nodes were identified in gamma probe in surgery. There were more hot nodes than blue. Total 359 sentinel nodes were removed. 101 patients were sentinel negative. 36 patients having sentinel positive had undergone ALND, in those, only 6 patients showed extra nodes positive in dissection. A median of 1-3 SLN were removed and in one case removed a maximum of 8 nodes. Identifying more sentinel nodes will increase confidence of surgeon to avoid ALND. 4 patients were false negative (4/137 ℒ2.9%), all underwent clinical breast examination every 3 months and mammogram at 1yr. In SLNB patients, follow-up showed no axillary recurrence and no arm lymphedema. Some case developed distant metastases after 1yr and some developed breast recurrence. 60 patients were not complete 1yr follow-up.

Conclusion: Among patients with early breast cancer treated with breast conservation surgery, SLND provides axillary control which is equal to ALND and less false negatives. SPECT CT helped in identifying exact location of nodes and a greater number of nodes and helps surgeon in removing node easily during surgery and there was no axillary recurrence in follow-up. This practice would improve clinical outcomes by reducing the complications such as lymphedema associated with ALND.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 32: Correlation of metabolic parameters on baseline FDG PET/CT with ALK1 driver mutation expression in treatment naïve patients of nonsmall cell lung carcinoma

A Palsapure ¹, N Purandare ¹, V Rangarajan ¹, A Agrawal ¹, S Shah ¹, I Dev ¹, R Kaushal ¹

Introduction: To assess the role of [18F]-FDG PET-CT metabolic parameters in predicting expression of ALK1/EML4 rearrangement in non-small cell lung cancers.

Materials and Methods: In this retrospective study, 67 patients of NSCLC who underwent FDG PET-CT and ALK-1 rearrangement testing were analysed. SUVmax values of primary site, nodal and metastatic sites were noted. Receiver-operating characteristics (ROC) analysis was used to derive a definitive cutoff for SUVmax of primary, nodes and metastatic sites. ManWhitney U test was applied to correlate metabolic parameters on FDG PETCT with ALK1 mutation status.

Results: ROC analysis yielded a cutoff of 17.09 for SUVmax of primary site with p value 0.04 and an AUC of 0.755. The OR for was found to be 9.33 (95% CI; 1.065-81.77). It was observed that patients with higher SUVmax (greater than 17.09) of primary had higher chances of getting ALK1 mutation concluding a positive strength of correlation using Mann Whitney U test. No correlation was found between the SUVmax of nodal & metastatic sites with ALK1 mutation.

Conclusion: Major challenges are faced during molecular profiling of the tumor owing to refusal by the patient to undergo any invasive procedure, insufficient tissue acquisition, sampling errors and unavailability of proper resources and centres. With prompt identification of ALK-1 driver mutation responsible for etiopathogenesis of the non-small cell lung carcinomas, targeted therapy in the form of ALK-1 inhibitors (such as crizotinib, ceritinib, lorlatinib) can be initiated at an early stage, thus improving the outcomes in such patients. Baseline FDG PET/CT parameter i.e. the SUVmax of primary site such as in our study has shown a positive correlation with ALK-1 mutation status and can be used as a non-invasive imaging modality to predict ALK1/EML4 rearrangement expression.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 33: Role of ¹⁸F FDG PET/CT in restaging of recurrent breast carcinoma

S Dikshit ¹, M Ora ¹, A H Nazar ¹, M Dixit ¹, A Agarwal ¹, P Lal ², S Gambhir ¹

Introduction: Breast cancer (BC) is one of the most common and leading causes of mortality due to cancer in females worldwide. The prognosis worsens steeply as the disease advances. Despite advancement in early diagnosis and adequate treatment, a significant proportion of the patients develop recurrence. Management of recurrent BC depends on adequate restaging. Local recurrence has to be differentiated from metastatic disease, which precludes radical treatment. 18F-FDG PET/CT scan is a hybrid molecular imaging. However, BC management guidelines have not included it as a standard modality. The study evaluated the role of 18F-FDG PET/CT in assessing patients with recurrent BC.

Materials and Methods: We evaluated 146 treated BC female patients in a single-center, retrospective study. These patients presented with recurrent disease after initial management. All patients underwent FDG PET/CT scans. Skull-base to mid-thigh acquisition was done, followed by a dedicated brain PET/CT acquisition.

Results: The mean age of patients was 50.6±12.2. A significant proportion (18.5%) of them were young (<35 years). The mean time to recurrence was 43.6±3 months. A high rate of distant metastases (88%) could be due to referral bias. Asymptomatic patients (18.5%) on regular follow-up also had distant metastatic spread. The mediastinal lymph nodes were the most commonly involved (54.7%) site. Other common sites of metastases were bone (43%), lung (40.4%), liver (26.7%), and operative bed (27.4%). Contralateral breast (14.4%) and brain (15.1%) were also seen in significant proportion of the patients. Metastases to the ovary (1.3%) and adrenal (2.7%) were rarely seen. Extra-thoracic involvement was common in patients who had symptoms confined to the intrathoracic region. Survival analyses showed a significant difference between the survival rates of those patients who showed early (< 2.5 years) and late recurrence (p-0.0001, median 95% CI 21.7-30.2 vs 35.6-78.3). Similarly, absent brain or liver metastases (p-value-0.01, median 95% of CI- 5.0-6.9) with Luminal A or B subtype histopathology (P-value- 0.04, median 95% CI- 21.8-42) was associated with better survival. Age at diagnosis (</=50 or >50yrs) (p=0.2), baseline staging (p=0.3), post-recurrence treatment (p=0.5), and the number of sites involved (p=0.6) did not affect survival.

Conclusion: Recurrent BC presents with advanced metastatic disease in most of the patients. Even the patients with localized disease disclose metastases on FDG PET/CT. FDG PET/CT has a definitive role in detecting locoregional, distant, and occult metastases. Patients with early relapse, brain and liver involvement, and atypical histopathology show poor prognosis. FDG PET/CT scan with dedicated brain acquisition can be used as a one-stop shop for imaging for recurrent BC. It may have a substantial impact on the management.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 34: Head-to-head comparison of FDG versus FAPI 04 PET CT for breast cancer

Arun Prashanth ¹, Senthil Kumar ¹, B Sridev ¹, Suman Kalyan ¹, E Prasad ¹, P Sunita ¹

Introduction: Breast cancer is the most common malignancy in women. However, the role of FDG PET-CT is rather limited in well differentiated, hormone expressing, lobular variant and luminal A tumours. Fibroblast activation protein (FAP) is expressed in cancer associated fibroblasts of breast cancer. FAPI 04 is a small molecule inhibitor of FAP. Ga-68 FAPI 04 (FAPI) PET CT imaging has shown promising results compared to FDG in various malignancies. Our aim is to compare the roles of 68Ga-FAPI-04 PET/CT and 18F-FDG PET/CT in the staging of primary breast cancer as well as in metastasis evaluation of recurrent breast cancer.

Materials and Methods: This is a retrospective study comparing FDG and FAPI PET CT scans in breast cancer patients. Study period was between January 2021 to August 2022, in a quaternary care institution. A total of 34 female patients underwent both FAPI and FDG PET CT within a span of 2 days. Demographic details, histopathologic findings including IHC markers, grading and variant of breast cancer, visual and semiquantitative analysis of both PET CT scans were analysed. Histopathology for staging and follow-up scans for recurrence were used as reference standards respectively. Mood's median test and Mann-Whitney U test were implemented for non-parametric pairwise comparison between variables.

Results: A total of 84 scans (42 each for FDG and FAPI) for 34 patients including follow-up scans were performed. The indication was staging in 33/42 (79%) and recurrence evaluation in 9/42 (21%) patients. Luminal A subgroup seen in13/42 (31%), Luminal B in 20/42 (48%), triple negative group in 8/42 (19%) and Her2 type in one patient (2%). Mean primary tumour size is 24mm (±23mm). Mean SUVmax of primary in FDG is 6.55 (±7.0) and FAPI is 9.26 (±7.2) with p-value of 0.02. TBR (Tumour background ratio) for primary lesion in FDG is 5.06 and for FAPI is 7.91 with a p-value of 0.03. However no significant difference is seen in the nodal/background ratio between FDG and FAPI. 15/42 (35%) had distant metastasis with significant difference in the number of skeletal, hepatic and other metastatic sites (p<0.05).

Conclusion: Higher tumour background ratio and increased metastatic site detection is seen in FAPI compared to FDG PET CT in staging and recurrence of breast cancer. FAPI opens a new paradigm in breast cancer imaging with potential impact in diagnosis and management. Further FAPI has a promising theranostic value for breast cancer in future.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 35: (⁶⁸Ga) Ga-DOTA.SA.FAPi PET/CT in the assessment of WHO grade 3 Neuro-endocrine tumors

Sanjana Ballal ¹, Prashant Mishra ¹, Madhav Prasad Yadav ¹, Nicky Wakade ¹, Parvind Sheokand ¹, Euy Sung Moon ¹, Shipra Agarwal ², Madhavi Tripathi ¹, Ranjit Sahoo ³, Chandrasekhar Bal ¹

Introduction: Minimal or lack of somatostatin receptor (SSTR) expression with a high [¹⁸F]F-FDG avidity is a characteristic of grade 3 neuroendocrine tumors (NETs) and an independent prognostic factor associated with an increased risk of death. For patients who are [¹⁸F]F-FDG positive but SSTR PET negative, the disease cannot be effectively targeted with either octreotide or PRRT. Hence, newer theranostic molecular probes are crucial for opening new targeted therapeutic options in aggressive NETs. Cancer-associated fibroblasts (CAF)-related markers such as fibroblast activation proteins (FAP) are potential alternate therapeutic targets for aggressive NETs. The study aimed to study the diagnostic performance [⁶⁸Ga]Ga-DOTA.SA.FAPi and compare the results with [⁶⁸Ga]Ga-DOTANOC and [¹⁸F]F-FDG PET/CT findings.

Materials and Methods: Fifteen patients (11 males and 4 women; mean age: 40.8 ± 16 years) with histologically confirmed grade 3 NETs were enrolled and underwent [⁶⁸Ga] Ga-DOTA.SA.FAPi, [⁶⁸Ga] Ga-DOTANOC, and [¹⁸F]F-FDG PET/CT scans. The quantitative assessment included comparing standardized uptake values corrected for lean body mass (SUL_peak and SUL_avg). Findings on both the scans were validated with diagnostic computed tomography.

Results: Fifteen patients had five types of NETs: pancreatic NET in five, mesenteric NET in one, carcinoids in seven, ovarian NET in 1, and NET appendix in 1 patient, respectively. [⁶⁸Ga] Ga-DOTA.SA.FAPi demonstrated a significantly higher uptake for all the primary lesions [SUL_peak 14.1 vs 3.6, p-0.0078], lymph nodes SUL_peak [8.68 vs 4.1, p-0.0159], bone [SUL_peak 9.3 vs 2.8, p-0.0001], and liver metastases [SUL_peak 8.3 vs 4.8, p-0.0033] compared to [⁶⁸Ga] Ga-DOTANOC.

Conclusion: [⁶⁸Ga]Ga-DOTA.SA.FAPi PET/CT imaging is a promising new imaging modality in [⁶⁸Ga]Ga-DOTANOC negative, [¹⁸F]F-FDG positive NETs. It has the potential to open a new avenue for treatment of high grade NETs.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 36: Pattern of skeletal metastasis in adenocarcinoma of gall bladder

Vineet Mishra ¹, Prakash Singh ¹, Raaja Chhabra ¹, Aftab H Nazar ¹, Shivangi Dikshit ¹

Introduction: Carcinoma of gall bladder is an uncommon cancer worldwide. However, the incidence varies according to geography and this is not very uncommon malignancy in Indus-Ganges belt of north Indian peninsula. Gallbladder cancer is characterized by early adjacent organ invasion, extensive loco-regional lymph node metastasis, and vascular and common bile duct involvement, which often precludes its curative resection and portends universally poor prognosis of the disease The rare site of metastasis are spleen, CNS, bone and skin. This retrospective study, we reviewed the FDG PET-CT of patients among the patients of Ca Gall bladder for bone metastasis.

Materials and Methods: In this retrospective study, we reviewed the PET-CT database for the patients diagnosed with Ca GB who underwent FDG PET-CT scan between January 2017 to October 2022 at Department of Nuclear Medicine, SGPGIMS, Lucknow. Focal FDG avid skeletal lesions were considered positive for skeletal metastasis. Their other FDG avid lesions, biochemical parameters and survival data were recorded and analysed. Diffuse bone marrow FDG uptake were not considered as skeletal metastasis.

Results: Out of 264 patients with diagnosis of Carcinoma gall bladder who underwent FDG PET-CT, only 7 (2.6 %) patients had FDG avid skeletal lesions. Out of 7 patients with bone metastasis, 6 were females and only one was male. Their age ranges from 39 years to 70 years (mean- 53.7 years; median- 55 years). Out of 7, 5 had liver and regional lymph nodal metastasis. Interestingly, 4 patients had left supraclavicular lymph nodal metastasis. Among the bone metastasis the most common site of involvement in our study was vertebrae (6/7) followed by pelvic bones (3/7) and ribs (2/7). However, none of the patients had solitary bone metastasis. On considering the CT features, three patients had lytic lesions, 2 had sclerotic lesion, 1 had central lytic lesion with sclerotic rim and one did not have any obvious lesion on CT component. The survival of these patients ranges from 3 months to 11 month (mean- 6.6 months; median- 6 months) from the date of FDG PET-CT scan.

Conclusion: Bone metastasis is a rare manifestation of adenocarcinoma of gall bladder. When found, it is usually associated with advanced disease involvement and decreased survival. However, solitary skeletal metastasis was not found in our study and skeletal lesions were always accompanied by hepatic or regional lesions.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 37: Molecular evaluation of myocarditis using ⁶⁸Ga DOTATATE and ¹⁸FDG in rest MPI normal but symptomatic, suspected acute myocarditis patients

Sutapa Rakshit ¹, Basant L Malpani ¹, Sunita Sonawane ¹, Nawab Singh Baghel ¹, A K Tyagi ¹

Objective: Myocarditis a rare inflammatory process of the heart muscle, can be acute or chronic in nature. Endomyocardial biopsy is the gold standard to prove myocarditis. ¹⁸FDG imaging is a probable potential diagnostic tool for early evaluation of myocarditis but it is nonspecific in nature as its uptake is seen in normal myocardium as well. ⁶⁸Ga DOTATATE, a somatostatin receptor based radiopharmaceutical which shows promising results for the assessment of myocardial inflammation as these receptors are expressed on immune cells. The objective is to compare¹⁸FDG and ⁶⁸Ga DOTATATE imaging for early diagnosis of myocarditis at molecular level.

Materials and Methods: Hospitalised patients, clinically suspected of acute myocarditis kept on carbohydrate-free diet for 48 hrs, were called after 6 hrs of fasting for ¹⁸FDG PET/CT scan. 50IU/kg heparin was injected 15 minutes prior to ¹⁸FDG injection (approximately 5 mCi). Patients were called again for ⁶⁸Ga DOTATATE PET/CT scan next day (approximately 2 mCi was injected) without any diet restrictions. Regional cardiac scan was carried out1 hr after injection on both the days using standard protocol on PET/CT system (GEMINI TF-16, PHILIPS). Seven patients (age: 18-57 yrs, male:1, female:6) underwent both the studies. Three ⁶⁸Ga DOTATATE patients' scans were acquired at 2 time-points to see washout of the tracer. Reconstruction was performed using RAMLA method. The data was visually analysed for both ¹⁸FDG and ⁶⁸Ga DOTATATE scans using fusion software. SUV_mean of liver, spleen, lung, bone marrow and heart were noted for both type of scans.

Results: Based on the visual assessment of the images, variable myocardial uptake pattern (patchy, diffuse and focal) and mediastinal lymph node uptake was observed in both the scans. In myocardium ¹⁸FDG uptake range (SUV_mean: 0.8-2.8) and ⁶⁸Ga DOTATATE uptake range (SUV_mean: 0.7-2.6) was noted. Average heart/lung (H/L) ratio for ¹⁸FDG was noted as 3.72±0.92 (mean, SD) and average heart/lung (H/L) ratio for DOTA was noted as 4.04±2.44. Average myocardium uptake ratio of ¹⁸FDG to ⁶⁸Ga DOTATAE 1.47±0.48.

Conclusion: ⁶⁸Ga DOTATATE is being reported in recent studies as marker for atherosclerotic inflammation. We observed that the SUV_mean of ⁶⁸Ga DOTATATE uptake in myocardium is less than that of ¹⁸FDG. The probable reason may be low density of receptors present in inflammatory cells of myocardium. We previously found that heart to lung ratio (H/L) of ⁶⁸Ga DOTATATE uptake as 1.82±0.19 in normal population in a retrospective study. Only one patient out of 7 shows uptake more than the threshold uptake of 1.8. Therefore, it is difficult to comment on the sensitivity of ⁶⁸Ga DOTATATE scan in myocarditis detection based on the results of our study population.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 38: Role of (⁶⁸Ga) Ga-DOTA.SA.FAPi PET/CT imaging in the assessment of breast cancer

Sanjana Ballal ¹, Parvind Sheokand ¹, Madhav Prasad Yadav ¹, Nicky Wakade ¹, Prashant Mishra ¹, Frank Rösch ¹, Euy Sung Moon ¹, Shipra Agarwal ², Chandrasekhar Bal ¹

Purpose: This study aimed to compare the diagnostic performances of [⁶⁸Ga]Ga-DOTA.SA.FAPi and [¹⁸F]FDG PET/CT in detecting primary breast tumors and metastasis.

Materials and Methods: A total of 47 breast cancer patients were included in the study and underwent both [⁶⁸Ga]Ga-DOTA.SA.FAPi and [¹⁸F]F-FDG PET/CT scans. Both imaging modalities were compared according to patient-based and lesion-based analysis.

Results: The mean age of the patients was 44.8 ± 9.9 years (range: 31 – 66). 85% had invasive ductal carcinoma, and 15% had invasive lobular carcinoma. 12 patients had triple negative disease, 17 had HER2-positive, and 18 had HER2-negative disease. 95.5% patients had distant metastases, in two patients the disease was locally advanced, and one patient did not have abnormal scan findings on both the scans. The median Tumor-to-Background Ratio (TBR) was higher for [⁶⁸Ga] Ga-DOTA.SA.FAPi than that of [¹⁸F]F-FDG for both primary and all metastatic lesions but statistically in case of lymph node, pleural metastases, liver and brain metastases.

Conclusion: [⁶⁸Ga] Ga-DOTA.SA.FAPi PET/CT is a promising theranostic agent in the imaging of breast cancers can be used as a complementary imaging to [¹⁸F]F-FDG PET/CT.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 39: The role of FDG PET/CT in necrotizing fasciitis – Challenging and rare clinical condition

P Verma ¹, P Shinde ¹, RV Asopa ¹

Introduction: Necrotizing fasciitis is a rapidly progressive infection of the deep soft tissue with a high mortality rate. Establishing the diagnosis is challenging and requires a high index of clinical suspicion. Patients may present with signs and symptoms of sepsis, including high fever, hypotension, and multiorgan failure. The main clinical challenge is distinguishing superficial from deep soft-tissue involvement.

Materials and Methods: This was a retrospective analysis of 4 patients (4 males; age range 38-64 years; mean age 50.25 years) presenting with pain, fever and soft tissue inflammatory signs on clinical examination in a specific region with a differential diagnosis of osteomyelitis, cellulitis and necrotizing fasciitis. They were referred for 18F-FDG PET/CT scan to evaluate the site of infection and well as to look for any occult sites of infection in the rest of the body. 18F-FDG PET/CT findings were compared to the clinical examination findings and follow up. The patients were given the diagnosis of necrotizing fasciitis based on clinical and imaging findings. They were managed conservatively with antibiotics according to culture sensitivity evaluation, daily dressing and followed up regularly.

Results: FDG PET/CT of 4 patients revealed 9 lesions in total (2 lesions per patient for 3 patients and 3 lesions in the 4^th patient). Two of these were not seen in initial clinical evaluation and were closely followed up. The lesions showed FDG uptake with mean SUV max 5.1 (range 1.51-7.77) and involved soft tissue in intermuscular and intramuscular planes with air foci and surrounding fat stranding and extending to overlying skin.

Conclusion: Necrotizing fasciitis is a rare life threatening disease that requires immediate attention. Due to the vague presentation and rarity of the condition, it may go undiagnosed in early stages. The differential diagnosis is cellulitis, osteomyelitis or any other local inflammatory pathology. FDG PETCT imaging can be used to enhance the sensitivity and specificity for the diagnosis of Necrotising fasciitis. FDG PET CT allows whole body scan and so it is possible to detect lesions in other areas and evaluate them. It may also potentially be used for treatment response in these patients.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 40: Preparation of 68Ga-NODAGA-RGD dimer as a radiotracer for tumor imaging at RMC

Ashok R Chandak ^1,², P Verma ², G Malhotra ², M K Ray ²

Introduction: The aim of the present work was radiolabeling and in-vivo evaluation of NODAGA-[RGD(y)K]₂ with ⁶⁸Ga³⁺ eluted from a commercial ⁶⁸Ge/⁶⁸Ga generator and used clinically for tumor imaging (thyroid cancer). Targeting tumor cells or tumor vasculature by peptides is a promising strategy for delivering cytotoxic drugs for cancer therapy. The Arg-Gly-Asp (RGD) dimeric sequence has been known to bind effectively with the α_vβ₃ integrin receptors expressed on the surface of angiogenic blood vessels or tumour cells. This study deals with preparation of ⁶⁸Ga-NODAGA-RGD dimer, its physicochemical and preclinical study in normal rat and clinical evaluation in follicular thyroid carcinoma patient.

Materials and Methods: The NODAGA-[RGD(y)K]₂ (ABX) was used (25 μg) for labeling with ⁶⁸Ga obtained from ⁶⁸Ge/⁶⁸Ga (50 mCi/1850MBq, itG/itM) generator. The synthesis was carried out aseptically using Eckert & Ziegler automated module as per the RPC approved protocol. The products were evaluated for physicochemical characteristic, stability and biodistribution in normal rat using PET camera. In vivo study was done in 50 years old male with follicular thyroid carcinoma and comparing ⁶⁸Ga-RGD uptake with 18FDG PET study in the same patient.

Results: Full scale automated synthesis of ⁶⁸Ga-RGD dimer was done with more than 70 % product yield using acetate buffer (1.0M) of pH 4.0, at 95^oC heating for 400 sec. More than 60 % injected activity in rat was excreted in 1 hr which is correlating with the reported study. In vivo administration of ⁶⁸Ga-RGD in a patient with carcinoma thyroid revealed avid uptake in multiple metastatic skeletal lesions with associated soft tissue component (right scapular lesions, right sided second rib, vertebrae, sternum, and bilateral iliac bones) correlating with FDG PET/CT findings.

Conclusion: The physicochemical and other quality control data was found in compliance with the standard guidelines of the ⁶⁸Ga-based preparations. ⁶⁸Ga-RGD showed good avidity in the patient with thyroid carcinoma and thus, can be used for tumor imaging. However, further studies with larger number of patients are required to substantiate our findings.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 41: Pattern of interictal brain perfusion defects in children with drug-resistant epilepsy – An institutional experience

S Sanisetty ¹, P K Panda ¹, P Pradeep ¹, Manishi L Narayan ¹

Introduction: Cerebral perfusion and metabolism are coupled in most physiologic and pathologic conditions, which strongly correlate with the intensity of neuronal activity. Imaging of brain perfusion with ictal, peri-ictal & interictal SPECT plays a key role in the localization of epileptogenic region and guidance for the subsequent management, especially in drug-resistant epilepsy, where, EEG, MRI& clinical findings are either discordant or normal. We have retrospectively evaluated the brain perfusion patterns in children with drug-resistant epilepsy referred to Nuclear Medicine department, AIIMS, Rishikesh. Aim of the study is to study the patterns of interictal brain perfusion on 99mTc-ECD SPECT in children of age 1-18 years with drug-resistant epilepsy (uncontrolled seizures on > 2 AED).

Materials and Methods: Interictal brain perfusion SPECT was performed according to standard protocol, using 0.2 to 0.3 mCi / kg with a minimum dose of 3 to 5 mCi of 99mTc-ECD. Tracer was injected intravenously at rest, during the seizure-free period (> 24 hrs) in supine position and brain SPECT was acquired 45 mins post-injection. Reconstructed images were analyzed by an experienced Nuclear Medicine Physician. Location, as well as the severity of perfusion defects, were noted and correlated with respect to the duration of disease, EEG, clinical and other imaging findings.

Results: A total of 19 patients (14 males & 5 females) with drug-resistant epilepsy with a mean age of 10+5 (range 1-18) years were analyzed. 9/19 (47%) patients had normal MRI brain study and 4/19 (21%) patients had normal EEG records, while in 2 patients both MRI and EEG were unremarkable. In all patients interictal brain perfusion SPECT was abnormal. Medial temporal lobe hypoperfusion was seen in all patients. However, 3/19 patients had other focal areas of hyperperfusion in addition to temporal lobe hypoperfusion. 6/19 patients had involvement of one hemisphere and 13/19 showed perfusion abnormalities in both hemispheres. Moderate to severe perfusion defects were seen in 13 patients. SPECT findings were concordant in 12/19 (63%) of cases.

Conclusion: Interictal SPECT was abnormal in almost all patients and, SPECT was able to provide additional information for diagnosis in the current patient group, where other clinical, lab findings, EEG & MRI were either discordant or unremarkable. It was observed that the patients with a duration of onset of symptoms <1 year had mild or subtle perfusion defects, while those with disease duration of >1 year had moderate to severe perfusion defects. Also, in a substantial number of cases bilateral hemispheric involvement and additional findings were noticed.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 42: Early response assessment with FDG PET-CT, post neoadjuvant chemo-radiation in patients of carcinoma oesophagus: Unseen challenges in interpretation

R Pandey ¹, S Taywade ¹, R Kumar ¹

Introduction: Time interval between neoadjuvant chemo-radiation (NACT-RT) and surgery is critical in management of patients with carcinoma oesophagus. Late surgery increases the chances of pathological complete response, however it is associated with intra-operative difficulty in dissections due to radiation induced dense fibrosis. Thus, early surgery is preferred by some surgeons. On the other hand FDG PET-CT is recommended post 8-12 weeks of radiotherapy in order to avoid inflammation related false positivity. So, early FDG PET-CT needs different approach in interpretation. We evaluated various metabolic response patterns in patients with carcinoma oesophagus who underwent early PET-CT post NACT-RT.

Materials and Methods: We reviewed FDG PET-CT studies of 109 patients with carcinoma oesophagus who underwent FDG PET-CT in department of Nuclear Medicine between February 2020 to September 2022. Total 16 patients underwent FDG PET-CT within 90 days of receiving RT were analysed retrospectively.

Results: The mean age of the 16 patients who underwent early PET-CT post RT was 50.81 years. There were 10 females and 6 males. The average duration between the RT and PET-CT was 44.18 days. Baseline PET-CT was available for 9/16 patients. 5/16 patients had focal FDG avid lesions pointing towards residual disease and their post-operative histopathological examination (HPE) revealed significant residual tumor cells (4-pT3 and 1-pT2). Amongst 11 patients with PET-CT picture of only post-treatment changes, 2 had post-operative HPE showing residual disease (1-pT3 & 1-pT2). Scan of patient with pT3 histopathology showed metabolism along the length of oesophagus with a focal hypermetabolic nodularity and in the other, it was a false negative finding. Among the remaining 9/11, 7 had post-operative HPE showing only post treatment changes with no evidence of tumor, 2 didn't undergo surgery (1 is on follow-up considering the age & comorbidities, 1-patient is scheduled for surgery). The characteristics of post RT changes include: 1. Significant reduction in size & metabolism of primary lesion in oesophagus and previously seen metastatic lymph nodes 2. Heterogeneous or mild diffuse uptake in oesophagus in the region of RT. 3. No significant thickening or mild diffuse thickening in the oesophagus 4. The uptake is more along the intraluminal/mucosal surface 5. There is increase in extent of FDG uptake in the region beyond the the known primary site in oesophagus.

Conclusion: Tumor metabolic activity post treatment strongly correlates with histopathological response. With studies showing benefits of early surgery post CTRT in carcinoma oesophagus, there is a need for standardization of the optimal timing for response evaluation by FDG PET-CT as well as define the metabolic response criteria. This study concludes that the scans done in early setting needs a careful evaluation with different interpretation approach to reduce the false positive rate due to radiation induced inflammation.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Onco 43: Design and development of novel folate compound for targeted imaging of folate receptor positive carcinomas

Dhirendra Jaiswal ¹, Reeta Chaudhary ¹, Puja Panwar Hazari ¹, Anil K Mishra ¹, Nitin M Nagarkar ¹, Mudalsha Ravina ¹

Introduction: Almost all cancers show modified metabolism, which is easily detected by SPECT (Single Photon Emission Computed Tomography) and PET (Positron Emission Tomography), these modalities are widely used in oncology imaging for prognosis and disease management. There are many altered metabolisms, and Folate metabolism is among them. Folic acid has been frequently exploited for targeting overexpressed folate receptors on malignant cells. It is well known that many malignant tissues consistently express high levels of folate receptors, which have been presented as an attractive target for tumor-selective drug delivery and imaging through the specific combination with relevant ligands of folate molecules. The folic acid/folate-receptor high-affinity interaction can be used to image cancer cells. High Tumour uptake of malignant tissues are found in biodistribution studies that allowed imaging of FR positive cancers. Clinical biomarkers are still needed to improveearly detection, predict malignant transformation and optimize therapies. Synthesis and preclinical evaluation of 99m Tc labeled FR positive conjugated derivative proclaimed that the reactions were very complex so there is need to make a simple and easy chemistry to synthesize a novel 99m Tc-Folate derivative so as to promote clinical application by simplifying the preparation process, and improving drug targeting in vivo are the problems to be solved.

Materials and Methods: The synthesis of a SPECT radioprobe involves different conjugation method with different radionuclides which shall be explored by trying different synthetic reactions. There is certain synthetic strategy followed for obtaining any chemical compound. Modified folate derivatives were purified by HPLC column and characterized by 1H NMR and HRMS. Numerous radiopharmaceutical were synthesized such as 99m Tc-1, 4, 7-tris (carboxymethyl)-10-(4-aminoethyl)-1, 4, 7, 10-tetraazacyclo-dodecane (DO3A-EA)-Folate by conjugating DO3A-EA to the γ-carboxyl group of folic acid and 99m Tc-labeled gold nanoparticle (NP) modified with folic acid. Feng et.al developed [99m Tc]Tc-CN5FA and [99m Tc] Tc-CNPFA in 2021 using isonitrile as a BFC, methylene chain and PEG chain as linkers. In vitro and in vivo studies demonstrated the high affinity and specificity of these probes for targeting FR.

Results: Radioactive probe shall be linked to Folic acid (pteroylglutamic acid) via glutamic acid or pteroic acid moiety. The Folate conjugates have the ability to be used as a receptor specific targeted radiopharmaceuticals for imaging over-expressed folate-binding protein in folate receptor positive carcinomas.

Conclusion: The novel 99m Tc labeled Folate derivative will be synthesized taking lead from the synthetic reactions of 99m Tc-TEPA-Folate where they have used tetraethylenepentamine as a strong chelating agent on the γ -carboxyl group of folic acid which provides binding site to the reduced technetium.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 1: Glomerular filtration rate of prospective voluntary kidney donors and renal reserve analysis in Indian population: A single-centre study

Lokeshwaran Madurai Kalimuthu ¹, Kavali David Jaya Prakash ¹, Vijay Singh ¹, Ayush Mishra ¹, Manish Ora ¹, Sukanta Barai ¹, Sanjay Gambhir ¹

Objective: The aim of this study was to measure the glomerular filtration rate (GFR) in voluntary kidney donors (VKDs) and to estimate their renal function reserve (RFR).

Methods: All VKDs were to asked follow a normal-protein vegetarian diet (1 g protein/kg body weight; advice was given regarding its composition) for 10 days before and during the study period (2 days). On the day of the study, all subjects were asked to report in a fasting state of 12 hours. All were given good oral hydration with 5 mL/kg of plain water before 30 minutes of the study. One millicurie of freshly prepared technetium 99m diethyl-triamine-penta-acetic acid (^99m Tc-DTPA) was administered intravenously, and baseline GFR was obtained from calculating plasma clearance of ^99mTc-DTPA by obtaining 2 venous blood samples of 4 mL each at 60 and 180 minutes postinjection by using the modified Russell's algorithm. All participants were called again on the following day after overnight fasting of 12 hours for measurement of protein-induced hyperfiltration GFR (GFRAAI). All were given oral hydration (plain water, 5 mL/kg), and after 30 minutes of hydration, an intravenous infusion of 10% mixed amino acids was started at a rate of 0.035 mL/min/kg after a sensitivity test for the entire study period. One millicurie of freshly prepared ^99m Tc-DTPA was administered intravenously, and stimulated GFR was measured from calculating plasma clearance of ^99mTc-DTPA according to the same protocol used in the baseline study. Renal functional reserve of each VKDs were calculated. Adequate RFR was considered as more than 20% increase in GFR with respect to baseline.

Results: Total 1233 VKDs were included in the final analysis (male-325 and female-908). The study revealed that the mean age of the study population was 46.3 years. The mean predonation GFR was 74.616.4 ml/min/1.73m² BSA, GFRAAI was 84.921.3 ml/min/1.73m² BSA. Sixty two percent of the VKD (male-24.3% and female-75.7%) had adequate renal reserve, whereas 38% of the VKDs were found to have an inadequate renal reserve.

Conclusion: GFR measurement is the most important investigation in evaluating prospective voluntary kidney donors. The National Kidney Foundation guideline accepts normal GFR as 120 mL/min/1.73 m². This cutoff value does not appear to be appropriate in an Indian population with a normal GFR of approximately 74.6 mL/min/1.73 m², and a lower cutoff value should be considered. Renal functional reserve may be used to identify subclinical forms of chronic kidney disease, helps in risk stratification of AKI before injury and predicts the future trend of GFR in donor. In our study we found that Indian population has lower GFR than western population and RFR was inadequate in more than one third of the study population.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 2: A comparative study of the calculation of glomerular filtration rate in dynamic renal scintigraphy using diethylenetriamine penta-acetic acid with the chronic kidney disease epidemiology collaboration equation in obstructive uropathy patients

Amandeep Kaur ¹, Ramneek Kaur Brar ¹, Yasmeen Atwal Sonik ¹, Bhayav Sonik ¹

Introduction: Glomerular filtration rate (GFR) is a useful parameter for assessing overall kidney function. Many methods are used to measure GFR namely: the double plasma sample method (DPSM), the Gates method and the Equation-based method. Among them, DPSM is the gold standard in clinical research, but it is time-consuming and requires timed blood sampling. On the other hand, Equation-based method and the Gates method using the camera based technique are both simple and reliable. So, in this present study, we compared the Gates method with the Equation-based method such as Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) in patients with obstructive uropathy.

Materials and Methods: A total of 248 patients referred to our Nuclear Medicine Department for the Diethylenetriamine Penta-Acetic acid (DTPA) dynamic renal scan during the study period of February 2021 to September 2022. 100/248 patients with obstructive uropathy were included in this present study. After adequate hydration, in-house Serum Creatinine evaluation was done to estimate GFR (eGFR) using the CKD-EPI equation as recommended by National Kidney Foundation (NKF) guidelines of 2014. Subsequently on the same day, the patient underwent a renal scan and GFR was calculated by applying Gates method (mGFR). The patients were divided into three groups based on their eGFR (ml/min/1.73m²) values, according to NKF guidelines: Group A: > 90, Group B: 60-89, and Group C: 60. Pearson correlation coefficient was calculated to find any correlation between mGFR and eGFR as per age distribution and eGFR range group according to NKF guidelines.

Results: Out of 100 patients (age range: 18-83 years; mean age: 42.32 years), 50% were males (age range: 18-80 years; mean age: 36.96 years) and 50% were females (age range: 20-83 years; mean age: 47.68 years). The mean serum creatinine was 0.89 mg/dl for the overall population; 0.93 for males and 0.83 for females. The mean mGFR in ml/min/1.732m2 for the entire population was 78.81, for males were 80.83, and for females were 76.60. On the other hand, the mean eGFR in ml/min/1.732m2 for the entire population was 98.95, and for males and females were 104.488 and 93.48. The Pearson correlation coefficient (R) for 18–40 years was 0.5016, 0.26 for 41–60 years, and 0.3311 for 61–90 years. Similarly, the R value was 0.3985 for Group A, 0.4774 for B, and 0.0303 for C. From the results, it is evident that there is a positive but weak correlation between mGFR and eGFR values.

Conclusion: To conclude, CKD-EPI gives information about global renal function only, where as Gates method apart from giving global renal function also provides information about split renal function and drainage pattern. Moreover, it does not require timed blood sample collection. Thus, camera based method using Gates protocol should be the preferred choice for GFR measurement in clinical practice.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 3: To study the correlation of textural parameters of the primary tumor on 18F-FDG PET/CT with immunohistochemistry markers in patients with locally advanced breast cancer

K Bishnoi ¹, K Agrawal ¹, G Parida ¹, S Majumdar ¹, P Mishra ², D Muduly ³

Introduction: Breast cancer is the most common cancer among women worldwide. Its morbidity is second highest amongst all cancers. Standard treatment protocols are based on clinical, pathological staging. PET is non-invasive modality for cancer diagnosis, staging. 18F-FDG is most often used radiotracer. Radiomics “Texture analysis” creates quantitative features from digitised images and shows heterogeneity within tumor, which is found to be related with tumor cell proliferation, angiogenesis and necrosis. All these characteristics are linked to advanced tumor and worse outcome.

Materials and Methods: 25 patients with histologically proven locally advanced breast cancer for initial assessment with no history of previous neoadjuvant chemotherapy were included after obtaining written informed consent. Tumor size <2 cm or any synchronous/metachronous malignancy were excluded. 18F-FDG scans were done on a dedicated GE Discovery MIDR PET-CT scanner. The patients included were fasting for at least 4hrs before study. Blood glucose levels were <200mg/dl. Intravenous injection of 8mCi dose of F18-FDG was given. CECT scan followed by PET was acquired at 60 +/- 5 minutes after radiotracer administration with an acquisition time of 2 minute/bed position. Textural features were extracted using LIFEx software (version 7.2.0) with threshold set to 40% of SUVmax.

Calculated quantitative parameters are:

SUVmax
MTV
TLG
First order imaging variables – Mean value, Variance, Volume Count, Root mean square, Skewness, Kurtosis, Uniformity
Second and higher order imaging variables – Grey Level Run Length Matrix (GLRLM), Grey Level Size Zone Matrix (GLSZM).

These were correlated with ER, PR, HER2-neu receptors, Mib-1 expression of primary tumor.

Results: A total of 25 patients were included with median age of 53 (28-65) years. Moderate correlation was considered as >0.5 – 0.7. Good correlation was considered >0.3 – 0.5. Correlation of various pathological parameters with radiomic features were found as follows: Table 1

Table 1.

Correlation of various pathological parameters with radiomic features

	Parameter	Correlation	P
PR	Mean	−0.53	0.006
	RMS	0.51	0.007
	LGLRE	0.54	0.005
	HGLRE	−0.51	0.008
	SRLGLE	0.55	0.004
	SRHGLE	−0.51	0.009
	LGLZE	0.56	0.003
	HGLZE	−0.51	0.009
	SZLGLE	0.57	0.002
ER	Mean	−0.42	0.03
	RMS	0.40	0.04
	HGLRE	−0.41	0.03
	SRHGLE	−0.43	0.02
	HGLZE	−0.41	0.03
	SZLGLE	0.40	0.04
PR	Skewness	0.45	0.02
	SRE	0.40	0.04
	Run percent	0.41	0.04
Mib-1	Mean	0.44	0.02
	HGLRE	0.43	0.03
	SRHGLE	0.43	0.02
	HGLZE	0.43	0.03
	SZLGLE	−0.42	0.03

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PR: Progesterone receptor, ER: Estrogen receptor

It can be interpreted that fine features with higher grey level intensity are seen in PR (-) and fine features with lesser grey level intensity are seen in PR (+) tumors. Fine features are higher in PR (+) than PR (-) tumors. Also, fine features with higher grey level intensity are seen in ER (-) and fine features with lesser grey level intensity are seen in ER (+) tumors. Finer high grey level features are seen with higher Mib-1 index and finer low grey level features are seen with lower Mib-1 index.

Conclusion: The ER/PR/Her2-neu receptor status and Mib-1 index are based on biopsy sample examined. However, radiomic features analyse whole of the primary tumor included in ROI (drawn based on SUV threshold). Thus, it can be a potential pre-treatment biomarker for diagnostic as well as prognostic aspect.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 4: The role of Tc-99m-human serum albumin scintigraphy in the diagnosis of protein-losing enteropathy

J R John ¹, J Hephzibah ¹, D Mathew ¹, N Shanthly ¹, A John ¹

Introduction: Protein-losing enteropathy (PLE) is characterised by excessive loss of plasma proteins into the gastrointestinal tract. Tc-99m Human Serum Albumin (HSA) scintigraphy is an important diagnostic modality for diagnosis of PLE since its introduction in 1986. This method is simple and sensitive not only to diagnose PLE, but also to localize the site of protein loss in the gastrointestinal tract which is almost impossible in certain cases with other imaging modalities. The aim of our study was to reinforce the diagnostic utility of Tc-99m HSA scintigraphy in a group of patients suspected of having PLE and to investigate the significance of 24 hours delayed imaging.

Materials and Methods: After intravenous injection of 740MBq of freshly prepared 99mTc HSA, static images were obtained at 10, 30, 90 minutes (early phase) and at 24 h (delayed phase). A 99mTc HSA scan was considered positive for PLE if there was visible tracer exudation in the gut. We retrospectively reviewed eighty Tc-99m HSA scans in the past 5 years (between October 2016 and October 2021), presenting consecutively with suspicion of PLE. We evaluated all the images with respect to visualization and initial appearance time of abnormal radioactivity.

Results: Thirty-two patients were positive on scintigraphy and showed abnormal 99mTc HSA activity in the bowel. There was a male preponderance (62.5%) with median age of presentation 34years (range 5-75years). Among them, ten (31%) demonstrated abnormal tracer activity only on images obtained 24 hours after injection. The underlying causes (confirmed on biopsy) included Crohn's disease (n=9), intestinal lymphangiectasia (n=4), abdominal tuberculosis (n=2), Celiac disease (n=2), Systemic Lupus Erythematosus (n=1), Cronkhite Canada syndrome (n=1), Menetrier's disease (n=1), lymphatic obstruction (n=1), Giardiasis (n=1), congestive enteropathy (n=1) and idiopathic (n=9).

Conclusion: Tc-99m HSA scintigraphy is convenient and useful for imaging patients with suspected PLE. The entire gastrointestinal tract can be imaged at one time to permit detection of multiple potential sites of protein loss. Delayed imaging at 24 hours has incremental value, thereby increasing the sensitivity of imaging (possibly because of the intermittent nature of this protein loss).

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 5: Compression of scintigraphic images using singular value decomposition

Jagrati Chaudhary ¹, Anil Kumar Pandey ¹, Priya Yadav ¹, Param D Sharma ¹, Chetan Patel ¹, Rakesh Kumar ¹

Introduction: Singular Value Decomposition (SVD) factors a matrix into three matrices: left singular vectors, singular values, and right singular vectors. Singular values contain dominant patterns of the data, larger singular values contain most dominant pattern while least singular values in magnitude contains least significant information of the data that can be safely deleted, and then matrix can be approximated with the remaining singular values; which leads to the compression of the original matrix. The objective of the study was to compress the Scintigraphic images (Planar images, PET/CT Studies, TRODAT SPECT studies, and Renal Dynamic Studies) using Singular Value Decomposition.

Materials and Methods: Planar studies (251 images), PET/ CT studies (49 studies), TRODAT SPECT studies (44 studies), and Renal Dynamic Studies (50 studies) were compressed by thresholding the singular values of the images by using Gavish and Donoho's Algorithm. Two nuclear medicine physicians compared the quality of compressed images with its original image for loss of any clinical details, and presence of compression generated artifacts. The quality of compressed images was also evaluated using objective image quality metrics (SSIM, Blur, Global Contrast Factor, Contrast per pixel, and Brightness). In Planar studies images, we were calculated difference in ROI counts from compressed and original image. A mask of size pixels was used to extract the ROI counts from compressed and original image in the PET/CT studies. We also compared the TRODAT uptake in basal ganglia estimated from compressed image and original image. The error in split function i.e., the error between split function calculated from compressed image and split function calculated from original image was computed. Wilcoxon test was applied to find statistically significant difference between the parameters used for comparison at alpha=0.05.

Results: Nuclear Medicine Physician found the quality of compressed image significantly better than the original images; and the compressed images were less noisy, better signal to noise ratio, and no compression artifacts noticed [Figure 1]. Based on objective assessment, the compressed image quality was better than its original image. There was insignificant difference of ROI counts between the input and compressed image of Planar study images and PET/CT studies. In 39 out of 48 studies, the percentage difference in TRODAT uptake (in basal ganglia from compressed and original image) was negligible (approximately equal to zero). In remaining 9 studies, the maximum percentage difference was 13%. Time activity curve generated from original and compressed image frames were identical. There was insignificant difference of ROI counts between the input and compressed image frames of 99m-Tc LLEC RD Study. The overall percentage compression was found to be in the range of 50 to 80%.

Conclusions: Compressed images were visually identical to the original image. The percentage compression was found to be up to 50-80 %.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 6: Head-to-head comparison of (⁶⁸Ga) Ga-DOTA.SA.FAPi versus (¹⁸F) F-FDG PET/CT in radioiodine resistant thyroid cancer patients

Nicky Wakade ¹, Sanjana Ballal ¹, Madhav P Yadav ¹, Frank Roesch ¹, Euy Sung Moon ¹, Marcel Martin ¹, Shipra Agarwal ², Madhavi Tripathi ¹, Ranjit Kumar Sahoo ³, Chandrasekhar Bal ¹

Introduction: [¹⁸F] F-FDG is a standard and valuable diagnostic imaging modality for radioiodine resistant thyroid cancers (RAI-R TC). Recently, molecular imaging probes targeting cancer associated fibroblasts (CAFs) have gained prominence and have proved to be potential alternative to [¹⁸F] F-FDG PET/CT in oncological imaging. This study aimed to compare the diagnostic efficacy of [⁶⁸Ga] Ga-DOTA.SA.FAPi and [¹⁸F]-FDG PET/CT in RAI-R TC patients.

Materials and Methods: We prospectively enrolled 91 RAI-R TC patients [48 females, 43 males; mean age: 51.5±12 years]. Qualitative assessment parameters included comparing patient-based and lesion-based visual interpretation of both the scans. The quantitative assessment included comparing standardized uptake values corrected for lean body mass (SULpeak and SULavg). The findings on both scans were validated with the morphological findings of the diagnostic computed tomography.

Results: 36 had single remnants, and 9 had bilateral remnant lesions with a complete concordance in the detection rate on both PET scans. [⁶⁸Ga]Ga-DOTA.SA.FAPi showed a higher detection efficiency rate for lymph nodes (sensitivity 95.74% vs 88.6%, p<0.0001), liver metastases (100% vs. 72%; p<0.0001), brain metastasis (100% vs. 38.8%; p-0.0003). Except for brain metastasis (SULpeak [⁶⁸Ga] Ga-DOTA.SA.FAPi vs. [¹⁸F]-FDG: 13.76 vs. 6.68) and muscle metastasis (SULpeak FAPI vs. FDG: 9.56 vs. 5.62) there was no significant difference in the median SUL uptake values between the radiotracers.

Conclusion: [⁶⁸Ga]-DOTA.SA.FAPi showed a superior detection efficiency for lymph node, liver, bowel, and brain metastasis. Unlike [¹⁸F]F-FDG, [⁶⁸Ga]Ga-DOTA.SA.FAPi can be used as theranostic probes in RAI-R TC. [⁶⁸Ga]Ga-DOTA.SA.FAPi provided complimentary benifit to the [¹⁸F] F-FDG-PET/CT scan in the imaging of RAI-R TC.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 7: Correlation and limitation between Russel's and Gates method

Sachin Tayal ¹, Varun Shukla ¹, Ravi Chauhan ¹, M V Manikandan ¹, Kumar Ajay ¹

Introduction: Since, its introduction in 1970, GFR estimation with the help of DTPA has been done routinely in Nuclear Medicine for evaluation of renal function. The first scintigraphic determination of GFR with the help of 99mTc DTPA, done by Garry Gates was adopted very soon due to its simplicity over invasive methods. Ours, being an oncological institute, we are routinely asked for GFR evaluation of patients to assess nephrotoxicity induced damage through GFR values before proceeding with next cycle of chemotherapy. To provide a more accurate alternative, plasma sampling method was also conducted on the same patient, and data was correlated.

Materials and Methods: A total of seven-minute dynamic study on fifteen patients, was acquired in a 64×64 matrix in two phases using GE's NMCT/670 DR Dual head gamma camera with a low energy high resolution collimator and patient positioned in supine position with arms elevated over the head. GFR was calculated based on the 2–3-minute uptake interval post injection. Needful correction for background activity and linear attenuation was done. Based on height and weight of the patient using Gates method one of the values was obtained. Secondly, for plasma sampling, 4 ml venous blood was collected at two and four hours after routine 99mTc DTPA using Russell's formula. The two values obtained through Gates and plasma sampling methods were comparted to find out for any correlation.

Results: Correlation value of 0.63 was achieved, indicating a moderate positive correlation.

Conclusion: Plasma sampling is a technically challenging, which requires a stringent protocol as chances of errors are innumerable. Most of which are, incorrect time of sample collection, erroneous preparation of standard, error in pipetting. Secondly, cases with extravasation of ^99mTc DTPA injection to be completely excluded. The result obtained does show a moderate positive correlation, however there is scope of improvement as we can minimise the various sources of error and comment strongly after having a larger sample size.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 8: Monitoring of radiation dose to personnel involved in labelling of ¹⁸⁸Re- radiopharmaceuticals

Mohd Hashim ¹, Naresh Kumar ¹, Anshika Pathak ¹, Priyanka Gupta ¹, Shamim Ahmed Shamim ¹

Aim: Rhenium-188 (T_1/2=16.98h) is a high energyβ⁻-emitting radioisotope (2.12MeV) obtained from the ¹⁸⁸W/¹⁸⁸Re-generator, which has shown utility for a variety of therapeutic applications in nuclear medicine. The low-abundantgamma photon155keV is efficient for imaging, bio-distribution, or absorbed radiation dose studies. The handling of such high levels of ¹⁸⁸Re imposes radiological precautions and adequate care that covers the ALARA principles. Our department has routinely started ¹⁸⁸Re-labelled radiopharmaceutical based therapies such as ¹⁸⁸Re-N-DEDC-lipiodol and Sn-colloid for the treatment of HCC and inflammatory arthritis, respectively. Thus, it became important to monitor the radiation dose received by the personnel involved during the manual synthesis of these labelled-radiopharmaceuticals. The present study aimed to monitor radiation dose received by personnel during the complete procedure (elution to imaging) of ¹⁸⁸Re-N-DEDC-lipiodol and ¹⁸⁸Re-Sn-colloid.

Materials and Methods: A radiation survey meter was used to measure background radiation exposure around the labelling work bench prior to start labelling procedure. A pocket dosimeter (Aloka mydose mini, PDM-222-SH, Southern Scientific Ltd, UK) was given to the personnel, placed in the pocket at chest level. Total 20 preparations were performed, each 10 for ¹⁸⁸Re-N-DEDC-lipiodol and ¹⁸⁸Re-Sn-colloid, the readings of radiation exposure were taken by using pocket dosimeter. The start and end time of procedure (elution to imaging) was noted down to know the total duration spent by radiation worker.

Results: Mean ¹⁸⁸ReO₄ used for labelling of ¹⁸⁸Re-N-DEDC-lipiodol and Tin colloid was 119.75±13.31mCi and 33.91±11.22mCi, respectively. Mean time required to complete the procedure (elution to imaging) was 94.83±1.85min and 171.1±4.31min, respectively. Mean wholebody radiation dose received was 0.019±0.0057mSv and 0.004±0.0011mSv, respectively, as measured by using the pocket dosimeter. Thus, mean radiation dose rate was 0.01±0.002mSv/h for ¹⁸⁸Re-N-DEDC lipiodol and 0.001±0.0004mSv/h for ¹⁸⁸Re-Sn-Colloid. Overall mean whole body radiation dose to the personnel involved in 20 radio-labelling procedures was found to be 0.011±0.0087mSv. Highest radiation exposure was received to personnel was during labelling of ¹⁸⁸Re-N-DEDC lipiodol as higher activity was handled and also higher amount of activity was required for therapy. However, the radiation exposure was under maximum limit of radiation worker.

Conclusion: The total effective dose to the personnel involved was 0.28mSv over 6 months which is far less than the stipulated limit of 20mSv. Our data suggests that the manual radio-labelling of ¹⁸⁸Re-labeled radiopharmaceuticals is safe and the whole body radiation exposure to the involved personnel is well within the prescribed limits of ICRP and AERB i.e., 20mSv/year (averaged over 5 years).

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 9: Mimickers on 99m Tc MDP triple phase bone scan in femoral head pathology – Armed forces tertiary institutional experience

B Asima ¹, B K Singh ¹, M G Vishnoi ¹, S S Wani ¹

Introduction: 99m Tc MDP triple phase bone scan is a powerful tool within the nuclear medicine diagnostic toolkit. The aim of this study was to assess the value of 99m Tc MDP triple phase bone scan in orthopedic cases of various pathologies involving femoral head which caused a diagnostic dilemma to the orthopedic surgeon. This study highlights the value of correlative imaging with CT, MRI and SPECT- CT in exact localization and characterization of the lesions which eventually lead to appropriate decision making by the orthopedician and patient management in cases where CT /MRI was inconclusive or contraindicated. A solitary skeletal lesion is always a cause of concern to orthopedician. Various bone pathologies have different uptake patterns. Femoral head is the most common site involved in various bone pathologies. However, benign tumors like osteoid osteoma, giant cell tumors, fibrous dysplasia, osteochondromas, enchondromas, unicameral bone cyst and aneurysmal bone cyst show intense uptake. Triple phase bone scan along with a SPECT or SPECT/CT helps us out to correctly characterize the lesion and increase the sensitivity.

Materials and Methods: This was a retrospective analysis done in armed forces tertiary institution on 10 patients subjected to 99m Tc MDP triple phase bone scan for patients who were referred by orthopaedic surgeon with diagnostic dilemma of 04 patients with suspected early AVN, 04 patients with suspected THR prosthesis infection and 02 patient with suspected malignant bone tumour. All patients underwent a triple phase bone scan with 99mTc- MDP after being injected with 740 MBq (20 mCi) intravenously. All patients were adequately hydrated. The scans were acquired after 3 hrs in anterior and posterior views on Siemens Symbia Intevo Bold Dual-head Gamma Camera.

Results: Patient were assessed based on multiple factors, including the H/o trauma, type of prosthesis, orthopedic intervention, course of patient's symptoms, physical examination findings, laboratory investigations, CT scan, MRI, planar triple phase bone scan and corroborative SPECT-CT scan findings. Out of 10 cases, 04 were suspected cases of prosthesis infection were found to have bone remodeling with no overt signs of active infection; 04 cases of suspected AVN where bone scan ruled out early phase of AVN and 02 cases of suspected malignant bone tumour which was found as unicameral bone cyst and giant cell tumour.

Conclusion: Early diagnosis of the primary lesion and timely orthopedic intervention is crucial for effective patient management and predicting prognosis. Femoral head is the most common site involved in multiple bone pathologies. Though CT scan and MRI is a commonly used imaging modality, bone scan has high diagnostic accuracy. Triple phase bone scan along with corroborative SPECT CT offers the advantage of characterizing the lesion and adds to the sensitivity particularly in cases where CT and MRI are inconclusive or contraindicated.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 10: Restoration of Tc-99m methoxyisobutyl isonitrile parathyroid scan images using richardson-lucy algorithm

D Sonker ¹, A K Pandey ¹, J Jaleel ¹, V Baghel ¹, P D Sharma ², C D Patel ¹, R Kumar ¹, C S Bal ¹

Background: Scintigraphic images are noisy and have poor resolution. It can be improved using image restoration algorithm. In this study, the optimal input parameters; point spread function (PSF) and the Number of iterations (NITERS) of the Richardson-Lucy algorithm were experimentally determined to restore Tc-99 m Methoxyisobutyl isonitrile (MIBI) Parathyroid scan images. Further, these optimum values of input parameters are validated.

Materials and Methods: A set of 60 anonymized Tc-99m MIBI Parathyroid scans was included. Optimum value of PSF and NITERS were estimated as follows: Ten images were processed with PSF [(size, sigma): (3,0.5), (5,0.75), (7,1), (9,1.5), (11,1.75), (13,2)] and for each PSF, NITERS ranged from 1 to 10. The processed images were visually compared with its corresponding input image, and the value of PSF and NITERS that resulted in best image quality were considered as optimum value. For validation, remaining 50 images were processed with optimum values of the parameters. Image quality of observed and restored images was assessed objectively using blind/reference less image spatial quality evaluator (BRISQUE), mean brightness (MB), discrete entropy (DE), and edge-based contrast measure (EBCM) image quality metrics. It was subjectively assessed by two nuclear medicine physicians (NMPs) by comparing the restored image quality with observed image quality visually and assigning a score to each restored image on the scale of 0-5.

Results: Based on BRISQUE, DE, EBCM and MB scores, restored images had superior perpetual quality; more detailed information, less contrast around edges and were less bright compared to input images. Based on visual assessment as well, the restored images had improved resolution; NMPs assigned an average image quality score of 3.9 (~4) to restored images. Through these observations, optimum value of PSF was estimated as PSF (size: 11 pixels, sigma: 1.75 pixels) but there is no single value for optimum NITERS. Optimum Value of NITERS depended upon the quality of input image and was interactively estimated for each image. Maximum resolution enhancement was noticed at PSF (size: 11 pixels, sigma: 1.75 pixels) and NITERS = 5. With increase in NITERS, noise also gets amplified along with resolution enhancement and affects visualization & differentiation of parathyroid nodes, small lesions or multiple lesions in close proximity of each other or thyroid; in the case of relatively low count noisy input images, the NITERS = 3 (majority of cases) gave better results.

Conclusion: Tc-99 m MIBI Parathyroid scan images were restored to improved image quality using the Richardson-Lucy algorithm. The optimum value of the PSF parameter was found to be of size = 11 pixels and sigma = 1.75 pixels.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 11: Optimizing the threshold for discrete cosine transform coefficients to achieve near loss-less compression of PET/CT image

Priya Yadav ¹, Anil Kumar Pandey ¹, Jagrati Chaudhary ¹, Chetan Patel ¹, Rakesh Kumar ¹

Introduction: A PET/CT scan has 200-300 images, each image contains diagnostic information of the patient. One PET/CT study requires approximately 150 MB space. The number of PET/CT scans performed is increasing day by day, this creates the need for Lossless compression of the compressing PET/CT study is required. We intend to explore DCT to achieve near lossless compression as it has the ability to pack most information in fewest coefficients. When DCT is applied on an image we get DCT coefficients equal to the number of pixels in an image. Larger DCT coefficients contain significant information while smaller coefficients contain the least significant information of the image, which can be discarded. Inverse DCT is applied to get back the compressed image. The aim of our study is to achieve near loss less compression of PET/CT images using Discrete Cosine Transform.

Materials and Methods: 15 PET/CT whole body studies (having total number of images: 11427) were acquired on Siemens Biograph mCT PET/CT scanner (Siemens Healthcare, Erlangen, Germany) with 64 slice CT in which CT scan was performed first using 120 kVp, 120 mAs and 5 mm slice thickness and then table moved to PET gantry. 18F-FDG dose (5.18-7.77 MBq/kg) was injected intravenously and after an uptake period of 60 minutes patients underwent whole body 18F-FDG PET/CT acquisition. Acquisition time was kept 2 min per bed position for 8 to 9 beds depending on height of patient. These images were exported in DICOM format and converted into PNG format. Discrete Cosine Transformation (DCT) was applied on these PNG images, which resulted in DCT coefficients corresponding to each pixel of the image. Two different thresholds equal to 5 and10 were applied and then Inverse Discrete Cosine Transformation was applied to get the Compressed 18F-FDG PET/CT scan Images. Nuclear Medicine (NM) Physician compared the compressed images with its input images. The results were also evaluated objectively using some image quality metrics: using Error, SSIM, FSIM, Multiscale SSIM. Results: NM Physicians found all the 1142718F-FDG PET/CT compressed images at both the thresholds i.e. 5 and 10 were acceptable [Figure 1]. All the images were identical to its input images with no loss of clinical information. However, the percentage compression achieved at threshold 5 and 10 for PET images were found to be 72.5% and 79.3% respectively and for CT images were 22.9% and 38.8% respectively. Our quantitative analysis supported the result of visual analysis. The SSIM, FSIM and Multiscale SSIM shows that the compressed images are structurally more similar to the input image. There was no error between compressed image and original image upto three decimal point. The median value of compressed SSIM, FSIM, Multiscale SSIM and Error for PET and CT images from its original image is given in Table 1.

Conclusion: All the PET/CT compressed images were exactly identical to its input image at both thresholds 5 and 10. Higher percentage compression achieved at threshold 10 for both PET and CT images.

Table 1.

Median value of SSIM, FSIM, Multiscale SSIM, and error of compressed positron emission tomography and computed tomography images from its original image at threshold 5 and 10

Parameters	PET		CT
Parameters	Threshold=5	Threshold=10	Threshold=5	Threshold=10
SSIM	0.64	0.57	0.80	0.75
FSIM	0.99	0.97	0.99	0.99
Multiscale SSIM	0.64	0.57	0.89	0.87
Error	0.00	0.00	0.00	0.00

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PET: Positron emission tomography, CT: Computed tomography, SSIM: Structural similarity index matrix, FSIM: feature similarity index matrix

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 12: Size and shape of point spread function is important in restoring Tc-99m methylene diphosphonate bone scan images using blind deconvolution analysis

Gagandeep Kaur ¹, Jagrati Chaudhary ¹, Anil Kumar Pandey ¹, P D Sharma ¹, Chetan Patel ¹, Rakesh Kumar ¹

Introduction: Blind deconvolution is the image restoration algorithm. MATLAB has function for performing blind deconvolution analysis of an image. The function requires two parameters: input image, and initial guess of PSF size by which input image might have been degraded; and returns estimated true image. As per MATLAB documentation, the PSF restoration is affected strongly by the size of the initial guess PSF and less by the values it contains (Shape of PSF). The main objective of our study is to verify this fact.

Materials and Methods: The experiment was performed on the retrospective data of 356 Tc-99m Methylene Diphosphonate (MDP) Bone scan static images. These images were acquired after 3-4 hours administration of 20-25 mCi Tc-99m MDP, on Siemens Symbia T6 SPECT/CT scanner. These DICOM images were converted into PNG format on personal computer and were restored using MATLAB blind deconvolution function. Input image was restored at different PSF sizes viz 3, 5, 7, 11, 13 and 15. Restored images obtained at each PSF size were compared with respect to input image and PSF size which resulted in best image quality was selected optimum PSF size. The criteria for selection of best image quality were that 'Restored image should be sharp and bright with high target to background ratio'. Further, Each Input image were restored independently at two different input parameters: 1. (PSF shape: Gaussian, PSF size: 11×11 pixel), and 2. (PSF shape: uniform, PSF size: 11×11 pixel). Restored images obtained at PSF shape: Gaussian, PSF size: 11×11 pixel were named as Gauss_PSF_Image and Restored images obtained at PSF shape: uniform, PSF size: 11×11 pixel were named as Uni_PSF_Image. Two Nuclear Medicine Physicians visually compared the restored images with its input image.

Results: As per NMPs, 342 out of 356 restored images by GaussPSF _ images were acceptable. GaussPSF _ images are more enhanced, bright, sharp with faithful visualisation of normal anatomical structures (spine and ribs) without any distortions in comparison to the other two images (input image and images restored with uniform PSF) [Figures 1 and Figure 2]. However, in some images, both Restored images were acceptable (14 out of 356 images) but still GaussPSF _ images were preferredover UniPSF_ images. GaussPSF _images are more sharp and less noisy while Slight Blurriness is observed in UniPSF_ images [Figure 3]. The significant difference observed between restored images with GaussPSF _ images and restored images with UniPSF_ images reveal thatperformance of the blind deconvolution is affected by shape of the PSF also.

Conclusion: Both PSF Size and shape plays an important role in restoring Tc-99m MDP Bone scan images using Blind deconvolution analysis.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 13: Extrinsic uniformity test using ⁵¹Cr flood phantom on 5/8” thick crystal SPECT gamma camera mounted with medium energy collimators – A feasible approach

K Biju ¹, Sushama Awasare ¹, Nawab Singh Baghel ¹, Sanjay Kumar Saxena ¹, Kamaldeep ², Sharmila Banerjee ¹

Aim: To check the feasibility and validity of ⁵¹Cr as flood source for performing uniformity test of gamma camera mounted with medium energy collimators.

Introduction: Extrinsic uniformity test is carried out to assess the overall performance of the Gamma Camera on daily basis before starting patient studies. Conventionally, this is carried out using flood phantoms carrying ^99mTc, ⁵⁷Coand ¹⁴¹ Ce on 3/8” thick crystal gamma cameras mounted with low energy collimators. However, it is not possible to use the same on 5/8” thick crystal gamma camera due to higher septal thickness of medium energy collimators. Therefore, intrinsic uniformity test has to be carried out using point source after removing the collimators, which is inconvenient and time consuming. Hence, there is a requirement of cheap and easily available medium energy flood phantom for this purpose. Though ¹³³Ba is a possible alternative but it is difficult to use for flood phantom due to its non-availability in India and ¹³¹I also cannot be used due to its physical properties being not suitable for the same. ⁵¹Cr, which has reasonably longer half-life (28 days) and 322 KeV energy (close to 364 KeV of 131 Iodine) can be explored for making flood phantom for carrying out uniformity test.

Materials and Methods: About 125 mCi 5.55 GBq (125 mCi) of Na₂⁵¹CrO₄ (obtained from BARC) was used to prepare flood phantom. Activity was added to the water filled flood phantom, mixed well and kept in a proper shielding case. Uniformity test is carried out on Siemens Symbia-E 5/8” thick crystal SPECT Gamma Camera system mounted with medium energy collimators. Data was acquired for 10, 000KCts with matrix size 256 × 256, and 15% window centered at 322 KeV.

Results: A good count rate of 15-17 kcts/sec was obtained with 125 mCi flood source with medium energy collimators. The quantitative analysis is carried out for uniformity test, using automatic software available with the system. Integral uniformity was calculated as <4.5% for both the detectors. Radiation exposure to the worker during preparationwasmeasured to be less than7uSv.

Conclusion: Due to the longer half-life of ⁵¹Cr, it was found to be suitable for preparing flood phantom for evaluation of extrinsic uniformity on a daily basis. It also serves as a convenient and time saving option. Further studies have to be performed to standardise this procedure.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 14: Development of a computer based program for estimation of radiation dose received by family members from neuroendocrine tumours patients treated with ¹⁷⁷Lu-DOTATATE

Pravind Maletha ¹, Kamal Deep ¹, Gaurav Wanage ¹, M K Suresh Kumar ¹, Sandip Basu ¹

Introduction: The last decade saw remarkable growth in the treatment of Neuroendocrine tumours (NETs) with radiolabelled peptides such as ¹⁷⁷Lu-DOTATATE. As per the regulations recommended in our country, this therapy can be given on an out-patient basis subject to the availability of dedicated ward with attached toilet for the patients (AERB/RSD/NM circular/2021/118). Radiological Safety Officer (RSO) of the facility must ensure that dose to the family members other than comforter does not exceed 1 mSv/y, prospectively estimated prior to discharge of the patient from the nuclear medicine department. The aim of this study was to develop a user-friendly computer-based program and estimate the dose received by family members from NETs patients treated with¹⁷⁷Lu-DOTATATE by using this computer program.

Materials and Methods: A total of 55 patients suffering from metastatic NET and undergoing ¹⁷⁷Lu-DOTATATE treatment at our centre were cohorts of this study. These patients were administered a mean activity 6.73 ± 0.94 GBq (4.88 – 8.40 GBq) of ¹⁷⁷Lu-DOTATATE. After administration of ¹⁷⁷Lu-DOTATATE, a calibrated plastic scintillator detector-based instrument (Dosimeter AT1121, Atomtex) was used for dose rate measurements at 1 m distance from the centre of the patient's abdomen. These dose rate measurements were primarily performed prior to the patients first void post-administration. These dose rate measurements were analysed as a part of this study, to determine the dose received by the family members of the patients treated with ¹⁷⁷Lu-DOTATATE. Depending on the time spent by the relative near the patient, the likely effective doses to the family members was calculated using the equation (1) (NCRP 1970);

graphic file with name IJNM-37-15-g002.jpg

where, D(∞) is accumulated dose for the total decay in mSv, 34.6 is the conversion factor of 24 hrs/day times the total integration of decay (1.44), Γ is the Specific gamma ray constant in mSv/GBq-hr at 1 cm [For ¹⁷⁷Lu this value is 48.92 mSv cm² GBq^-1 h^-1(Smith and Stabin, 2012)], Q₀ is the administered activity in GBq, T_eff is the effective half-life in days [For ¹⁷⁷Lu-DOTATATE, this value is taken as 1.15 days (Kamaldeep et al. 2022)], r is the distance from point source to the point of interest in centimetres (typically this value is 100 cm), E is the Occupancy factor (typically this value is taken as 0.25 in normal conditions of the patients). ΓQ₀= Dose rate at 1m at the time of discharge (J A Siegel, 2007). Based on the above equation a family members dose estimation program was developed and compiled in the Visual Basic programming language [Figure 1]. The output of the program was verified with the manual calculations performed by using above equation.

Results: The mean dose rate obtained at 1m distance from the centre of patient's abdomen was 18.88 ± 3.42 μSv/h (Range: 11.2 - 26.5 μSv/h). The mean radiation dose received by the family members of the NET patients treated with ¹⁷⁷Lu-DOTATATE was 0.19 ± 0.03 mSv (0.11 - 0.26 mSv). The output data obtained by the program agrees with the manual calculation performed by using equation 1.

Conclusion: The radiation dose received by the family members of NET patients treated with ¹⁷⁷Lu-DOTATATE is well below the limit prescribed by the competent authority. With the help of this computer-based program, it is easier and quick to predict the doses received by family members and accordingly the RSO can give the instructions to the patient and family members to be followed, after the discharge of the patient from the Nuclear Medicine department.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 15: Physicochemical and sterility testing of commonly used therapeutic radiopharmaceuticals – An AIIMS radiopharmacy experience

Anshika Pathak ¹, Naresh Kumar ¹, Mohd Hashim ¹, Shamim Ahmed Shamim ¹

Introduction: Therapeutic radiopharmaceutical requires high LET particles and high radiation dose, soit is necessaryto perform the physiochemical and biological tests to avoid the unnecessary exposure delivered to the patient. Dispensing a radiopharmaceutical of the highest quality reduces unnecessary radiation exposure and further reduces the risk of radiation induced side effects. Quality of final product depends on specific labelling methods under controlled manner based on specific standard operating procedures (SOPs) for each radiopharmaceutical production suggested by the manufacturer. Only limited data available on QC of therapeutic radiopharmaceuticals. Most of the data available is in conjunction with the clinical evaluation of that radiopharmaceutical, with little emphasis on the quality testing part. Thus, the present study is aimed to assess physicochemical QC and sterility of commonly used therapeutic radiopharmaceuticals.

Methodology: The physicochemical [pH, physical appearance, radiochemical (%RCP) and radionuclide purity (%RNP)] and sterility tests were performed in 20 samples of therapeutic radiopharmaceuticals (¹³¹I-NaI, -mIBG, ¹⁷⁷Lu-Sn-colloid, ¹⁷⁷Lu-PSMA, and-DOTATATE). paper was used to determine the pH of radiopharmaceuticals. The %RCP of sample was performed with 0.5 μl (up to 3μCi) of labelled radiopharmaceutical applied on paper or instant thin-layer chromatography strips (stationary phase), 1.5 cm from the bottom & developed in suitable solvent (mobile phase) till the solvent reaches about 0.5 cm from the top. After removing from solvent, strips were dried up and cut into two equal halves and radioactivity of each part was counted using a well counter (Biodex Atomlab 950 thyroid uptake system with optional well counter). The %RNP of radiopharmaceutical was determined by identifying the Gaussian energy peak of radionuclide in medical spectrometer software of well counter. Sterility test was performed with peptone as a growing media by mixing a suitable amount of activity of radiopharmaceutical. Further, the culture media containing radioactivity was incubated for atleast 48-72 hours at 37°C prior to processing to assess any growth in culture media.

Results: A total of 20 samples were taken that included 6 samples of ¹³¹I-NaI, 5 of ¹³¹I-mIBG, and 3 samples each of ¹⁷⁷Lu-PSMA, ¹⁷⁷Lu-DOTATATE, and ¹⁷⁷Lu-Sn-colloid. All samples were colorless on physical appearance except ¹⁷⁷Lu-Sn colloid which was cloudy yellow in appearance due to colloid formation. The pH was found to be approx. 8, 6, 5, 6 and 8 of ¹³¹I-NaI, ¹³¹I-mIBG, ¹⁷⁷Lu-DOTATATE, ¹⁷⁷Lu-PSMA and ¹⁷⁷Lu-Sn-colloid, respectively. Mean % RCP of ¹³¹I-NaI, ¹³¹I-mIBG, ¹⁷⁷Lu- DOTATATE, ¹⁷⁷Lu-PSMA and¹⁷⁷Lu-Sn-colloid was found to be 99.55 ± 0.42%, 98.06±1.32%, 93.36±3.26%, 99.16±0.57% and 93.75±4.27%, respectively. The Gaussian energy peak to assess % RNP using medical spectrometer software of well counter was found to be within ±10% of the specific energy peak of particular radionuclide. All 20 samples were found to be sterile at 37°C after 48-72 hours incubation.

Conclusion: Our study shows physicochemical and sterility tests results were within the permissible range of specific radiopharmaceutical according to SPC (Summary of Product Characteristics) guidelines.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 16: Gallium ℒ68 PET image restoration using nonlinear diffusion based Perona Malik Model

Sachin Saini ¹, Anil Kumar Pandey ¹, Sambit Sagar ¹, Chetan Patel ¹, Rakesh Kumar ¹

Introduction: In routine practice, the observed images are corrupted with random noise which arises during the image acquisition. A denoising process recovers the true image from the observed image. The search for efficient image denoising techniques still represents a valid challenge in the image processing domain. Such a restoration approach is intended to optimize trade-off between image smoothing, detail preservation and undesired effect removal. Unfortunately, the conventional restoration methods, such as the 2D Gaussian and average filters, generate the unintended blurring effect and cannot preserve well the edges and other image features. In this pilot study, we have investigated a partial differential equation (PDE) based image restoration model for restoration of Ga-68 DOTANOC PET/CT images.

Materials and Methods: The scans are performed on a dedicated PET/CT scanner at our department (SIEMENS, BIOGRAPH mCT 64) and (GE DISCOVERY PET/CT 710), as per standard protocol. Briefly, 68Ga-DOTANOC PET/CT acquisition has been performed after intravenous injection of 68Ga-DOTANOC, CT scan acquisition is performed first. After CT scan, PET acquisition was done for 8 to 9 beds depending on height of patient. The implementation of diffusion filter available in Mevislab is based on Perona Malik Model. Each trans-axial image (total number of images of PET/CT-6545, PET images:-2954 and CT images:-3591) of ten Ga68- PET/CT studies was processed with diffusion filter, and input and its restored images were inspected for lesions. The input parameters and its value of the diffusion filter are: {Time step size: 5, Number of iterations: 10, Edge parameter: 3 and Smoothing: 1}. The quality of output image was evaluated visually by comparing it with its input image.

Results: This model provide better filtering and edge preservation results. The edges and other important image features are preserved quite well as shown in Figure 1. Random noise in image is reduced and output images become smooth as shown in Figure 1. They still have some drawbacks, the main disadvantage is soft tissue contrast resolution reduce.

Conclusion: Images obtained using this filter is free from noise and edges are well preserved. At particular value of parameters {Time step size:5, Number of iterations:10, Edge parameter:3 and Smoothing:1}. However, reduction in soft tissue contrast was noticed. With our limited sample size it can be concluded that this filter can be used for pathologies involving cortex of the bone.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 17: Enhancement of less uptake lesions on Tc99m MDP bone scan using fuzzy logic

Sakshi Dogra ¹, Anil Kumar Pandey ¹, Angel Hemrom ¹, Rakesh Kumar ¹, Chetan Patel ¹

Introduction: Bone scintigraphy is a sensitivity diagnostic technique that can differentiate 5% of bone remodelling compared to other imaging modalities. Remodelling (osteoblastic activity) takes the shape of uptake in the bone scan. Amount of uptake is dependent upon two main factors (i) Clinical factor i.e. The amount of osteoblastic activity (ii) Technical factor involves scan time and numbers of counts in the image. Amount of uptake in the image is used for interpretation of the image. E.g., whole body skeletal image in which normal high uptake is seen in areas of high bone density (skeletal predominance) {spine (high uptake), long bone (low uptake)}, the small lesion surrounding high uptake required more attention and time and sometime got miss out. Fuzzy logic is introduced by Prof L.A. Zadeh in 1965 since then it is used to deal with uncertainty. Uncertainty in bone scan regarding the presence of small lesion arises because of poor lesion to background ratio. This problem can be solved using Fuzzy logic image contrast algorithm because Fuzzy logic is well suited in solving problems related with uncertainty. In this study we have used fuzzy INT operator for enhancing bone scan images.

Materials and Methods: In this study 177 Tc99m MDP bone scan images are pre-processed with the principle of dynamic stochastic resonance (DSR) (number of iteration-4 & 7) followed by bilateral filter and Fuzzy INT operator cross-over: 0.5, fuzzy Number of iterations:1. The resulting processed and input images were reviewed by two NM physicians. They compared the quality of the enhanced image with its input on the basis of overallcontrast, better lesion to background ratio, reduced noise and categorised it as acceptable (acceptable with input, acceptable without input) and unacceptable. The image quality was also assessed objectively using the four image quality metrics: blur, brightness, global contrast factor (GCF) and contrast per pixel (CPP).

Resuls: NM physicians preferred enhanced images over input images in approximately 80% (23% acceptable without input, 56% acceptable with input) and remaining 20% are better as input. Compared to input image, Enhanced images have improved lesion to background ratio in case of small lesions which makes lesions more clear [Figure 1]. Based on quantitative assessment of image quality, the quality of enhanced images was found to be significantly better than the quality of input images.

Conclusion: 80% of enhanced images have better contrast and lesion to background ratio.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 18: To evaluate the diagnostic utility of 99mTc-prostate-specific membrane antigen scintigraphy in comparison with Gallium-68-prostate-specific membrane antigen PET imaging: A gamma camera-based cost effective alternative prostate-specific membrane antigen imaging modality

Monika Hooda ¹, Baljinder Singh ¹, S K Singh ¹, Ravimohan Mavduru ¹

Introduction: Prostate cancer (PCa) is the second most common cause of cancer and the sixth leading cause of cancer death among men worldwide. PCa is rarely symptomatic early in its course. Gallium-68 (68Ga)-Prostate-Specific Membrane Antigen (PSMA) PET imaging is a molecular based PET imaging in PCa patients as PSMA is overexpressed on the surface of PCa cells. 99mTc-PSMA was evaluated in head-to-head comparison with 68Ga-PSMA in the present study as a cost-effective alternative.

Materials and Methods: Fifteen (n = 19, mean age 66.7 ± 9.9) male patients with histologically confirmed prostate carcinoma were included in the study. Maximum of 45.0mCi of 99mTc was added to the sterile, lyophilized and non-pyrogenic kit and it was boiled for 10.0min. Radiochemical purity was performed for the final preparation. 99mTc-PSMA imaging was performed in each patient within a week post 68Ga-PSMA imaging. The whole-body images were acquired at 4.0h of intravenous administration of freshly prepared 99mTc-PSMA (mean activity injected =13.7 ± 2.1 mCi) along with SPECT/CT (Symbia T16 Siemens, Germany) at 3.0h.

Results: The Radiopharmaceutical purity (RCP) of the prepared 99mTc-PSMA was >90.0%. The mean PSA levels were found out to be 85.9 ± 162.4 ng/ml. In patient-based evaluation, both 99mTc-PSMA SPECT/CT and 68Ga-PSMA PET/CT scans were positive in 94.73% (18/19). The pelvic SPECT/CT was compared to 68Ga-PSMA PET/CT pelvic region. A total of 99 pelvic lesions were identified in 68Ga-PSMA whereas, 81 lesions (81.8%) were picked up by 99mTc-PSMA. In whole body images of 99mTc-PSMA, a total of 52 lesions (89.6%) were identified other than pelvic lesions whereas, in MIP images of 68Ga-PSMA 58 lesions were identified in fifteen patients.

Conclusion: 99mTc-PSMA provided prostate cancer lesions' detection rate comparable to 68Ga-PSMA and thus can be used confidentially for prostate cancer work up. This may be cost effective imaging technique which will be of special interest for monitoring the response assessment to 177Lu-PSMA therapy in metastatic PC patients.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 19: Development and characterization of ¹³¹I labeled antibody for glypican-3 immunoradiometric assay

Insaf Kumar ¹, Sanjay Bharati ¹

Introduction: Liver cancer 3rd most common cause of cancer related deaths worldwide. Primary liver cancer can be sub-classified as hepatocellular carcinoma (HCC), hepatoblastoma, angiosarcoma and cholangiocarcinoma. At present, surveillance of high risk HCC population is done by estimating either serum markers alone or in combination with imaging modalities (USG, CT or MRI). These modalities suffers from limitations (Low reproductively, Poor sensitivity & specificity). Limitations necessitate the development and identification of an effective tumor marker with the potential of being used for early HCC diagnosis. Glypican-3 (GPC3) is protein biomarker, present on the surface of HCC cells. Up-regulated in HCC tissues and confirmed its secretion into the serum.

Methodolgy:

Step 1. Labeling of ¹³¹I with GPC-3was done using Chloramine-T (CAT)
Step 2. Separation of ¹³¹I from untagged antibody was done using size exclusion chromatography
Step 3. Purity of labeled antibody (¹³¹I-GPC-3) was checked by (SDS-PAGE)
Step 4. Radiochemical purity was checked by performing TLC.

Results: ¹³¹I was labelled with GPC-3 using the chloramine-T method. The resulting solution was added to size exclusion chromatography, separated via Sephadax G-50& measured under gamma counter. Different fraction (120) were collected. Samples from 1 to 10 did not show any count. Sample 15 and 16 exhibited highest peak counts of 1871cps and 1773cps, respectively. Samples from 17 to 20 showed a decline in the number of counts. Rest of the samples (21 to 120) exhibited negligible counts. Samples with higher activity (15 and 16) were further proceeded in a single well and the remaining 118 samples were clubbed and loaded in another well for SDS-PAGE. After the destaining, we visualized some bands in the gel. A standard sample of monoclonal antibody GPC-3 was visualized which corresponded to the 66kDa band of protein ladder. The band corresponding to 131I-AGPC-3 (s-15 & 16) was visualized near 75 kDa band of the protein ladder. However, the bands corresponding to all 118 clubbed samples (AGPC3 clubbed), were visualized as two distinctive bands, one below the molecular weight of GPC-3 (66kDa) and another above 75 kDa. The result showed that at the bottom portion of the 131I-AGPC-3 gel strip noted to have the maximum counts of 14 cps at the level of 63 to 75 kDa. The middle portion of gel shows 5 cps at the level of 76 to 135 kDa but at the top portion of the 131I-AGPC-3 gel strip noted to have only 3cps. Finally, 131I-AGPC-3 was applied to TLC paper was ruined and allow the strip to develop in 85% methanol. 131I-AGPC-3 remained at the start position and unbound 131I migrates to the front with a retardation factor of 0.8. RCP was approximately 93.8%.

Conclusion: Finally, labelling efficiency was found using thin layer chromatography. These results meet the radiochemical purity requirements set by USP for labelled compounds (93.8%).

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 20: Assessment of small bowel transit scintigraphy with ^99mTc-SC labelled with standard liquid meal: Establishment of reference values

Suman ¹, Naresh Kumar ¹, Sonu Kumar ¹, Priyanka Gupta ¹, Khangembam Bangkim Chandra ¹

Introduction: Small bowel transit scintigraphy is a single non-invasive technique that is used to quantifygastric emptying (GE) parameters and index of small bowel transit (ISBT) by using standard meal radiolabeled with ^99mTc-sulfur colloid. However, there are no reference values for liquid meal. Thus, present study aimed to assess the reference values of GE parameters and ISBT using a standard liquid meal.

Materials and Methods: Whole gut scintigraphy was performed after consuming a standard radiolabeled liquid meal containing 1 mCi of ^99mTc-sulfur colloid in 300 mL of potable water and another 50 mL of non-radiolabeled water to wash any activity sticking onto the oropharyngeal region and esophagus. Time-based (1-minute) static images encompassing the abdominal region were acquired on a dedicated gamma camera fixed with LEHR collimator, at 0, 0.5, 1, 2, and 4 hours. ROIs were drawn encompassing the gastric activity in the anterior and posterior images for each time point imaging up to the 4-hour image. For ISBT analysis, a large rectangular ROI was drawn encompassing the entire abdomen in the anterior and posterior images for each time point. The values derived on geometric mean (GM) method were compared to that derived on anterior view method.

Results: Fifteen (15) (3 male; 12 female) healthy volunteers having mean age of 44.4±6.44 years were recruited for the study. The median % GE at 0.5, 1, 2, and 4 hours were found to be 33% (21 – 58%), 11% (3 – 25%), 1% (0-10%), and 0% (0 – 4%), respectively by GM method. The median T_1/2 of GE was 21.62 minutes (18.5 – 37.4). The median values of total abdominal counts (TAC) at 4 hours were found to be 97 (39.41 – 144.71) and 43.7 (11.1 – 60.72) in the anterior view and GM methods, respectively. The difference was found to be statistically significant (P<0.01). In the anterior view and GM methods, the median values of terminal ileum beyond caecum (TIBYC) at 4 hours were 18.07 (0.83 – 76.14) and 5.83 (0.44 – 27.7), respectively. The difference was also statistically significant (P<0.01). According to the anterior view and GM methods, the median values of ISBT (%) at 4 hours were 20.5 (0.57 – 52.6) and 17.2 (0.72– 49.5), respectively. ISBT (%) for both anterior view and GM was found to be significant (p = 0.001), however, their difference was found to be statistically non-significant (P =0.091). The 5^th percentile value of anterior and GM method for ISBT calculated at 4 hours was 1.34% and 1.17%, respectively. Hence, the reference value of ISBT in anterior view and GM method at 4 hours was established as ≥1.34% and ≥1.17%, respectively.

Conclusion: The reference value of index of small bowel transit has been established as ≥1.17% and ≥1.34% in GM and anterior view methods, respectively at 4 hours. A value lower than the above-mentioned cut-offs may be regarded as delayed small bowel transit.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 21: Unconventional use of a common tracer: Case report on protein leak site localization using 99mTcMDP scintigraphy

Shranav Jha ¹, P Pradeep ¹, L S Sanjith ¹, Rajesh Mishra ¹, Vandana K Dhingra ¹

Introduction: Protein-losing enteropathy is a clinical condition determined by excessive protein loss in the gastrointestinal lumen due to various gastrointestinal diseases. Functional imaging modalities are of great importance for diagnosis of PLE as in most cases diagnostic work-up is difficult and can be inconclusive.

Materials and Methods: A patient with clinical suspicion of PLE was referred for99mTc-Human Serum Albumin study. In view of unavailability of the tracer and in reference to the literature, 99mTc-MDP scintigraphy was performed. After obtaining informed consent, 740 MBq of 99mTc MDP was injected under the gamma camera. Initial blood flow images for 1 minute at 2 seconds/frame followed by static blood pool images of the abdomen were acquired and were unremarkable. Sequential static images of abdomen were taken at 3 and 24 hours in anterior and posterior views.

Results: Our case showed abnormally increased radiotracer localization in right hemi-abdomen at 3 hours post injection on whole body bone scintigram which was followed by SPECT/CT for localization of tracer extravasation. SPECT/CT images revealed increased tracer activity in lumen of ascending colon with focal increased tracer collection at ileo-ceacal junction. An abnormal tracer leak into intestinal lumen was suspected and further confirmed with radioactivity in stool count the following day. Rest of the skeletal system revealed physiological tracer uptake and normal tracer excretion through kidneys.

Conclusion: Considering the clinical and biochemical profile of our patient and thorough understanding of 99mTc-MDP tracer kinetics and distribution, a diagnosis of abnormal radiotracer leak into terminal ileum and ascendingcolon was made suggesting the possible site of protein leak. Detecting the site of protein leak would play a vital role in patient management to guide tissue sampling and plan surgical intervention if required. Non-invasive evaluation of PLE using 99mTc HSA has been found sensitive but its availability is limited. Hence 99mTc MDP radiotracer could be considered as a cheap, readily available and reliable surrogate tracer of choice for evaluating the site of PLE, when a non-invasive evaluation of intestinal protein loss is explored.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 22: Extrarenal distribution of Tc-99m ethylenedicysteine in dynamic renal scintigraphy and its potential implications on scan interpretation

Sanchay Jain ¹, Deepa Singh ¹, Suruchi Jain ¹

Introduction: Extra-renal activity of Tc-99m EC on dynamic renal scintigraphy may result in interpretation pitfalls and dilemma. This case series demonstrates extra-renal distribution of Tc-99m EC and its potential clinical implications.

Materials and Methods: Sterile formulation kit for reconstitution with sterile Tc-99m sodium pertechnetate eluted from Molybdenum-99/ Tc-99m generator was used for Tc-99m EC preparation. Dynamic images of the abdomen in posterior view were acquired immediately after intravenous administration of recommended dose of Tc-99m EC on dual headed gamma camera with SPECT/CT system (GE Discovery NM/CT 670 DR). Furosemide was injected intravenously immediately or 10 minutes following radiotracer administration. Other views and/or SPECT/CT were acquired in selected cases. Correlation with clinical, biochemical, and other available imaging findings was also done.

Results: Tc-99m EC dynamic renal scintigraphy findings in four cases are described.

Case 1: A 34-year-old woman with history of right pyeloplasty. Dynamic images did not reveal dilated ureter. Delayed images at 2 and 4 hours revealed tracer uptake in the region of right ureter. This was due to tracer activity in the bowel (more prominent in anterior views). CT urography also did not reveal dilated ureter. Potential pitfall here is possible perception of bowel activity as ureteric activity.

Case 2: A5-year-old girl with enlarged and hydroureteronephrotic left kidney. Right kidney was not visualized in dynamic images. Tracer activity is noted in the right upper quadrant region and lower right renal fossa, corresponding to liver, gallbladder and bowel activity. Such pattern may falsely appear as faintly visualized right kidney and dilated ureter.

Case 3: A 3-year-old girl with pelvic pancake kidney and right pelviureteric-junction obstruction showed severely impaired perfusion and cortical tracer uptake in the right moiety of kidney. Delayed images at 2 and 4 hours showed an additional site of tracer uptake in the region of right renal fossa. Tc-99m DMSA scan revealed no renal tissue in the right renal fossa. Such distribution in a patient with single kidney may create illusion of poorly functioning second kidney.

Case 4: A 45-year-old-man with bilateral nephrolithiasis. Dynamic images showed small sized kidneys with impaired cortical tracer uptake. Delayed images at 2 and 4 hours also showed tracer uptake along the superolateral aspect of right kidney which on SPECT/CT images localized to abnormal tracer uptake within the gall bladder. Reporting errors may arise due to extra-renal activity in close proximity to the kidney.

Conclusion: Extrarenal tracer distribution of Tc99m-EC may cause interpretation pitfalls especially when in close proximity to the organs of urinary tract. This may arise due to alternate route of hepatobiliary excretion, and other factors related to radiopharmaceutical preparation or patient (interference with drugs, renal failure). Interpretation may become even more challenging in severely impaired renal function with high background activity. Correlation with additional views, SPECT/CT, clinical profile, renal function tests and findings of other imaging modalities is essential in these cases.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 23: Machine learning based classifier for renal cell carninoma versus tuberculosis using SVMradial with haralick features

Anil Kumar Pandey ¹, Sumit Garg ¹, Jagrati Chaudhary ¹, Aditi Khurana ¹, Param Dev Sharma ¹, Rakesh Kumar ¹

Introduction: Tuberculosis (TB) has been a diagnostic challenge for years and oncologists are expected to keep it high up in their list of differentials while staging and restaging the disease. Primary malignancy and bony metastasis are generally more FDG avid than are benign lesions. However, there are many exceptions to this concept. There is a great overlap between the metabolic representation of malignancy and TB which limits the value of FDG PET/CT in the same. CT texture analysis combined with FDG PET characteristics can be an adjunct to further characterize these lesions. This may help in avoiding unnecessary invasive biopsy procedures and enhance the diagnostic and staging accuracy. The objective of our study is to apply machine learning based classifiers to determine the etiology of metabolically active bony lytic lesions and classify them into two categories viz Renal Cell Carcinoma (RCC) and TB.

Materials and Methods: Lesions on PET/CT scans of histopathologically confirmed cases of 42 RCC and 42 TB patients were segmented. Three different datasets of feature vectors namely, 13 Haralick texture features (estimated from gray level co-occurrence matrix for 32 gray levels zero degree angle and 1 pixel distance), 26 Haralick features (13 at 1 pixel, and another 13 at 2 pixel distance), and 89 (other various features) were created. For each of three feature datasets, features having very high correlation greater than 0.70 were dropped. In this way, we had six different datasets of features vectors. Thirty different models of SVMradial classifiers were trained and tested on each datasets, for this 80% data (34 out of 42 from each RCC and TB) was used for training and 20% of data (8 out of 42 from each RCC and TB) was used for testing the performance of the model. During training a 10 fold cross validation technique was used. Six top performing models (one from each dataset) were compared. All experiments were performed on personal computer in R using the Caret package.

Results: One SVMradial classifier trained on 6 out of 26 features dataset had 94% accuracy, 88% sensitivity, and 100% specificity in classifying RCC versus TB. Three models had 69% accuracy, 88% sensitivity, and 100% specificity. Remaining two models had 69% accuracy, 63% sensitivity, and 75% specificity.

Conclusions: An SVMradial classifier trained on a features dataset obtained from selecting 6 out of 26 Haralick features (13 at 1 pixel, and another 13 at 2 pixel distance) having less than 0.3 correlation can produce a high-accuracy (94%) model for classifying RCC versus TB.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 24: Quantification parameters of^99mTc-MDP single-photon emission computed tomography/computed tomography in the diagnosis of active condylar hyperplasia

Mohammad Umar ¹, Dikhra Khan ¹, Sambit Sagar ¹, K V Sivashankar ¹, Anushna S Babu ¹, Hemant Khairwa ¹, Abhishek Gawande ¹, V Rahul ¹, Arup Roy ¹, Y S Manikya ¹, S A Kshitij Gyanraj ¹, Vikrant Goenka ¹, Shamim Ahmed Shamim ¹, Rakesh Kumar ¹, C S Bal ¹

Objective: Literature on condylar hyperplasia is scarce. ^99mTc-MDP SPECT/CT has a significant role for the identification of active condylar hyperplasia. To assess the quantification parameters oftechnetium-99mmethylenediphosphonate (^99mTc-MDP) single-photonemissioncomputedtomography/computedtomography (SPECT/CT) and SPECT for the diagnosis of active condylar hyperplasia (CH).

Patients and Methods: We enrolled retrospectively, 30 patients who underwent a ^99mTc-MDPbone scan along with regional SPECT/CT for the diagnosis of active CH. SPECT and CT images were evaluated by two nuclear medicine physicians in consensus. Radioactive counts were measured per region of interest and the respective percentages were calculated. The AP (anteroposterior) and TR (transverse) dimensions of the normal and abnormal side was measured on CT. A quantitative cutoff difference percentage score was also measured above which can be confidently reported as active CH. The difference percentage score was calculated by taking the counts on the abnormal side and normal side, then calculating extra percentage uptake on the abnormal side.

Results: 30 patients had a mean age of 20.84 ± 5.15years (95%CI) with 22males and 8 females underwent 99mTc-MDP SPECT/CT for suspicious CH evaluation in our department. Out of 30 patients, SPECT/CT was positive in 56% (17/30), while the rest of the 13 patients showed a negative scan. We calculated the uptake percentage of the positive scans using the formula (abnormal side counts/total counts x100) and found the mean uptake as 58%. We also calculated another quantitative parameter for the differentiation of disease from the normal side, namely the difference percentage score (DPS) (abnormal side counts-normal side counts/normal side counts x100). The average difference percentage of the 17 patients was found to be 63 %. The size of the condyles as measured on the CT showed, a mean AP measurement of 0.945 ± 0.36cm and TR measurement of 1.785± 0.18 cm at the abnormal side compared to the normal side mean AP measurement of 0.705 ± 0.14cm and TR measurement of 1.745± 0.27 cm respectively. There is a significant difference in anteroposterior CT measurements (p=0.05) of the abnormal and normal sides of the condylar hyperplasia. However, there was no significant difference (p=1.00) in transverse measurements among both groups.

Conclusion: Abnormal anteroposterior CT measurement of active condylar hyperplasia is the best CT parameter to differentiate between the two groups. While 99m Tc-MDP SPECT can predict active condylar hyperplasia with abnormal uptake and difference % (DPS) of 58 and 63% respectively for the diagnosis of active CH.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 25: A comparative phantom study: Effectiveness of 4D gated PET-CT over non-gated PET-CT in case of small lung tumor using QUASAR^TM programmable respiratory motion phantom

Saumya Shrivastav ¹, Bhujeet Kumar ¹, Anjli Shrivastav ², Mudalsha Ravina ³

Aim and Objective: The intention behind this study is to almost eliminate the motion artifact and its further consequences from the moving organ tumor PET-CT images. In PET CT images, Heterogeneity is one factor that is often associated with head and neck tumors (1), rectal carcinoma (2), and non-small cell lung cancer. In particular diseases, such as Lung Cancer, normal tissue motion and respiratory motion causes uncertainty for PET-CT guided Radiotherapy, which can affect both imaging and treatment delivery measurements that are patient and technology-dependent. For the same purpose data were obtained in two phases: Static phantom image without 4D gating & Static phantom image with 4D gating.

Materials and Methods: To eliminate the artifacts in PET-CT images from the target organ tumors due to respiratory motion we planned to perform a 4D gated phantom study. For the study, we utilized the QUASAR^TM Programmable Respiratory Motion Phantom. The respiratory tracking system used here is the Varian RPM system along with a flat couch mounted camera and a tracking device. The images were acquired using motion phantom with a custom PET/CT lung insert. For comparison purposes, we acquired data in two ways of moving lung tumors: without 4D gating and with 4D gating.

Results: We compared the gated image with the non-gated and found a satisfactory reduction in motion artifact.

Conclusion: After analysis of both the images (gated and non gated), it is concluded that 4D gating will be helpful to calculate exact SUV for small moving tumour which will help radiotherapy planning and treatment.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 26: A rare case of hennekam lymphangiectasia – Lymphedema syndrome and imperative role of lymphoscintigraphy in the diagnosis

S Abhilash ¹, P Pradeep ¹, S Sanisetty ¹, Manishi L Narayan ¹

Introduction: Hennekam lymphangiectasia–lymphedema-syndrome (HKLLS), a rare congenital disorder caused by abnormal genesis of lymphatic vessels associated with mental retardation, intestinal lymphangiectasia and lymphedema. Establishing the diagnosis of lymphatic malformation is a crucial step in diagnosis of HKLLS. Lymphoscintigraphy is a sensitive (96%) and very specific (100%) imaging tool for evaluation of lymphedema. Here the authors describe a case of HKLLS and role of lymphoscintigraphy in suspected lymphatic cause of bilateral recurrent lower limb edema.

Case Report: A 12 year old male child, born out of a consanguineous marriage, presented to our institute with history of intermittent episodes of fever associated with generalized body swelling, predominantly involving bilateral lower limbs, occurring every 3-6 months since the last 11 years. Similar symptoms have been documented in other male siblings in the family (aged 18 and 7 years). He had an uneventful antenatal history and a normal developmental history. He was vaccinated for age. He presented again to OPD with a history of fever and generalized swelling, which started as bilateral lower limb swelling and progressed to abdominal distension for over 7 days. It was associated with frothy urine and decreased urine output for 2 days. No history of chills, rigors, nausea, vomiting, altered sensorium, abdominal pain or altered bowel habits were present. On examination, he had lip ulcers, ascites, sacral edema, bilateral knee swelling, bipedal pitting edema and generalized lymphadenopathy (cervical, axillary and inguinal) & hepato-splenomegaly. Initial investigations revealed normocytic normochromic anemia (8.9 gm%), severe hypoalbuminemia (1.9 g/dl) and elevated C-reactive protein (220.5 mg/L). Urine routine examination and microscopy revealed 2+ albuminuria with granular casts. His S. Creatinine was 0.4 mg/dl; Hemoglobin was 10.2 g/dl; had lymphocytopenia (890 cells/cu.mm) but platelets were normal. Tropical fever work up including Mountoux, CBNAAT, Malaria (ICT), serology for dengue fever (NS-1, IgM, IgG) & enteric fever (IgM, IgG) were negative. Abdominal ultrasonography revealed minimal ascites, hepatosplenomegaly with bilateral pleural effusion. Lymphoscintography (LSG) was performed for him after intradermal injections of filtered 99mTc-Sulphur colloid (0.5 mCi) into interdigital web spaces of both lower limbs. LSG images revealed delayed ascent of tracer with sluggish lymphatic flow from superficial lymphatics of both lower limbs and dermal backflow in right lower limb. Suggestive of lymphatic blockage possibly consequent to malformation and dilatation of lymphatic channels.

Discussion: In 1989, a Dutch physician, Hennekam RCM explained a syndromic association of congenital lymphatic malformation with autosomal recessive transmission.[3] This syndrome is characterized by facial dysmorphism, mental retardation, intestinal lymphangiectasia with protein loosing enteropathy, hypoproteinemia, hypogammaglobulinemia, lymphedema of genitals and lower limbs. These constellations of symptoms could be explained due to impaired prenatal and postnatal lymph flow and lymphatic. Alders et al and Angela et al. has suggested the mutationin CCBE1 gene and loss of function mutation of ADAMTS3 gene association with HKLLS. Considering the rarity of incidence (1 in 100000) and very few case reposts on HLLS, establishing the diagnosis is crucial. Lymphoscintigraphy helped in identification of lymphatic obstruction thus establishing the diagnosis of lymphatic malformation causing lymphedema. There is no definitive management for lymphangiectasia. Treatment is primarily focused on management and prevention of complications like cellulitis, hypoproteinemia, and seizures.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 27: Optimization of Beam parameters for ⁶⁴Cu-production using radiactive simulation studies: INMAS medium energy cyclotron (16.5 MeV)

Sukvir Singh ¹, Puja P Hazari ¹

Introduction: With the advent of theranostics, novel radioisotopes and radiopharmaceuticals have been in demand for personalized precision medicine for various diseases such as cancer, neurological, infection, hypoxia etc. Local production of high purity radioisotopes using medical cyclotron is a cost effective and safer way of providing radiopharmaceuticals for various clinical usage with minimum scope of malicious diversion of the radioactivity. Solid targetary system is utilized to produce metallic radioisotopes of theranostic importance. Optimization of the production yield with respect to the beam parameters (energy, current, shape), target parameters (material, thickness, geometry), foil parameters (material, thickness), and duration of irradiation, is the critical factor in cost effective production of novel radioisotopes. Also, the target contamination with undesired radioisotopes studies are equally important for high purity clinical grade radioisotope production. Monte Carlo simulations are the computational methods to theoretically study and optimize the beam, target, foil parameters for optimum yield of a particular radioisotope prior to the actual target bombardment experimentations.

Materials and Methods: In the present study, We have conducted radioactive simulations on INMAS-PETtrace (GE Healthcare, 16.5 MeV, 30 μA) medical cyclotron with solid targetary system (Comecer) for production of Cu-64 radioisotope using ⁶⁴Ni(p,n)⁶⁴Cu nuclear reaction. GEANT4 (ver.11.0.2) Monte Carlo simulation toolkit was utilized to simulate Various simulations (10,000 iterations) were run to simulate the production yield of Cu-64 and other undesired radioisotopes (Co^-55,57,58,61 Cu^-58,60,61,62 Fe^-55, Ni^-57,63) for various nuclear reactions on enriched (95%) Ni-64 target of specified geometry. The validation of simulation codes was done by comparing the simulation reaction cross section of ⁶⁴Ni (p,n)⁶⁴Cu reaction at various energies (8 – 16.5 MeV) with the standard nuclear database TENDL (CERN).

Results: The simulation reaction cross section of ⁶⁴Ni(p,n)⁶⁴Cu was in agreement with that of TENDL 2019 data available on Cern website. The simulation yield of Cu-64 production was 7.21 mCi.μA^-1 for target energy of 11.32 MeV (target thickness 0.6 mm, diameter 6 mm, foil thickness 0.32 mm) which is in close agreement with the previous simulation studies conducted by Poignant et al (2016). The relative yield of contamination radioisotopes were maximum 0.32 for Cu-60 and minimum of 1.76 X 10 ^-3 for Cu-61. The relative yields of other radioisotopes were insignificant (< 10^-6) as compared to the Cu-64 radioisotope.

Conclusion: The current study successfully demonstrated the application of GEANT4 Monte Carlo simulations to study the production optimization of Cu-64 radioisotope through ⁶⁴Ni (p,n)⁶⁴Cu nuclear reaction as well as production of other contamination radioisotopes. The characterization of contaminated isotopes is important as part of radiation safety as well as the quality production of high purity radioisotopes. Further, the Monte Carlo simulation studies can be extended to study other target bombardments using proton as well as deuteron beams for production of newer radioisotopes of theranostic importance. It is a cost effective and radiologically safe tool to study the production of newer radioisotopes before indulging into the experimental studies.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 28: A deep learning approach to generate high count positron emission tomography images from low count positron emission tomography images using conditional generativeadversarial network

Sneha Mithun ^1,^2,³, Ashish Kumar Jha ^1,^2,³, Umeshkumar B Sherkhane ^1,², Biprojit Nath ², Akhilesh Tripathi ², Vinay Jaiswar ², Grace M Mehta ², Shreyash Panchal ^2,³, Nilendu Purandare ^2,³, Leonard Wee ¹, Andre Dekker ¹, Venkatesh Rangarajan ^2,³

Background: Positron emission tomography (PET) imaging requires a long imaging time causing discomfort to the patient and reducing throughput of the imaging department. Several efforts are being taken to minimize the scan time duration of the PET scan. This study aims to develop and evaluate the feasibility of a data-driven deep learning approach (deepLcAcHcAc) to generate high-count PET attenuation corrected images using low-count PET attenuation correction images.

Methods: A deep learning-based high count PET attenuation-corrected image generation pipeline (deepLcAcHcAc) was developed to generate high count attenuation-corrected (HAC) images using low count attenuation-corrected (LAC) images. A deep convolutional “2D-U-Net”-based architecture, and a convolutional “PatchGAN” classifier (Patch size:70 X 70) as the discriminator, which only penalizes structure at the scale of image patches was trained to generate HAC imagesfrom LAC Images. A set of 100 (29300 slices each HAC Images (45 sec per bed position) and LAC images (10 sec per bed position) and 25 (6210 slices each HAC and LAC image) retrospective whole-bodyPET scans were used to train and validate the model respectively. The model was evaluated by comparing the predictedHACimages with that of ground-truth HAC images using Peak Signal to Noise Ratio (PSNR), Structural Similarity Index (SSIM) and Multi Series Structural Similarity Index (multi-SSSIM). We also quantified the percentage difference in intensity of ground-truth and predicted images. The deepLcAcHcAc pipeline for image prediction is shown in Figure 1a.

Results: deepLcAcHcAc produced HAC PET images using LACPET images with validation PSNR 0.690 ± 0.024, SSIM 0.998 ± 0.01 and multi-SSSIM 0.999 ± 0.01. The average quantitative accuracy of predicted attenuation corrected images resultedin average errors of less than 2% for the background and less than 3% in the lesson when compared in 30 randomly selected transaxial slices. The difference between ground-truth and predicted images and the subtraction of both are shown in Figure 1b.

Conclusion: We developed and validated the automated deep learning approach (:deepLcAcHcAc) to generate a high-count attenuation corrected (HAC) PET image from a low count attenuation-corrected (LAC) PET image. The deepLcAcHcAc algorithm can accurately predict HACPET images from whole-bodynon-attenuation corrected PET images.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 29: A deep learning approach to generate positron emission tomography attenuation corrected image using Conditional Generative Adversarial Network

Ashish Kumar Jha ^1,^2,³, Umeshkumar B Sherkhane ^1,², Sneha Mthun ^1,^2,³, Biprojit Nath ², Akhilesh Tripathi ², Vinay Jaiswar ², Grace M Mehta ^2,³, Shreyash Panchal ^2,³, Nilendu Purandare ^2,³, Leonard Wee ¹, Andre Dekker ¹, Venkatesh Rangarajan ^2,³

Background: The attenuation correction of positron emission tomography (PET) imaging has always been challenging in PET-MRI scanners due to the unavailability of an attenuation map generated by CT or transmission scan. This study aims to develop and evaluate the feasibility of a data-driven deep learning approach (deepNAC-AC) for the generation of PET attenuation corrected images using PET non-attenuation correction images.

Methods: A PET attenuation correction pipeline was developed utilizing deep learning to generate attenuation-corrected (AC) images using non-attenuation-corrected (NAC) images. A deep convolutional “2D-U-Net”-basedarchitecture, and a convolutional “PatchGAN” classifier (Patch size:70 X 70) as the discriminator, which only penalizes structure at the scale of image patches.was trained to identify tissue attenuation in PET non-attenuation corrected image data and generate an attenuation corrected image. A set of 120 (33000 slices each AC and NAC images) and 20 (5900 slices each AC and NAC images) retrospective whole-bodyPET scans were used to train and validate the model respectively. The model was evaluated by comparing the predicted attenuated corrected PET images with that of actual attenuation corrected PET images using Peak Signal to Noise Ratio (PSNR), Structural Similarity Index (SSIM) and Multi series Structural similarity index (multi-SSSIM). We also quantified the percentage difference in intensity of ground-truth and predicted images. The deepNAC-AC pipeline for this work is shown in Figure 1a.

Results: deepNAC-AC produced attenuation corrected (AC) PET image using non attenuation corrected (NAC) PET image with PSNR 0.670 ± 0.02, SSIM 0.998 ± 0.01 and multi-SSSIM 0.999 ± 0.01. The average quantitative accuracyof predicted attenuation corrected images resultedin average errors of less than 2% for the background and less than 2% in the lesson when compared in10 randomly selected transaxial slices. The difference between ground-truth and predicted images are shown in Figure 1b.

Conclusions: We developed and validated the automated deep learning approach (deepNAC-AC) to generate attenuation corrected (AC) PET image from a nonattenuation-corrected (NAC) PET image. The deepNAC-AC algorithm can accurately predict attenuation corrected PET images from whole-bodynon-attenuation corrected PET images.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 30: Comparison study on CT radiomic features extracted from two disease cohorts-NSCLC and ca rectum

Grace M Mehta ¹, Shreyash Panchal ^1,², Ashish Kumar Jha ^1,^2,³, Sneha Mithun ^1,^2,³, Biprojit Nath ¹, Akhilesh Tripathi ¹, Umeshkumar B Sherkhane ^1,³, Vinay Jaiswar ¹, Nilendu Purandare ^1,², V Rangarajan ^1,²

Aim: Role of radiomic features in disease prognostication in oncology has being explored by many researchers in the past. Radiomic features have shown strong correlation with the various clinical endpoints in oncology. Aim of this study is to find if there is any correlation between the radiomic features extracted from two disease cohorts i.e. NSCLC and Ca-Rectum.

Methodology: Pre-treatment CT scans of 20 patients each of NSCLC and Ca rectum were retrospectively selected for this study. This retrospective study was approved by the Institutional Ethics Committee of Tata Memorial Hospital, Mumbai with the waiver of informed consent. The DICOM images were loaded onto the Philips IntelliSpace Discovery workstation and the region of interest was delineated. The tumor delineation was performed by expert imaging physicist and reviewed by expert radiologist. The delineation was named as GTV and stored as an RTSTRUCT file. The Mann-Whitney U test was performed to identify the difference between the radiomic features extracted from two disease groups. The level of significance was set at 0.05.

Results: In total 1093 Radiomic features were extracted from the tumor using PyRad-GUI software. 771 features i.e., 70.54% (771/1093) exhibited the significant difference between two disease groups. However, remaining 29.4% (322/1093) features did not show significant difference between two disease groups.

Conclusion: Our study suggests that the radiomic features extracted from two disease groups are distinctly different. These features may be explored for the disease prognostication in the future.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 31: Reproducibility of CT radiomics features by changing bin-width parameter and voxel resampling

Shreyash Panchal ^1,², Grace M Mehta ¹, Ashish Kumar Jha ^1,^2,³, Sneha Mithun ^1,^2,³, Akhilesh Tripathi ¹, Biprojit Nath ¹, Umeshkumar B Sherkhane ^1,³, Vinay Jaiswar ¹, Nilendu Purandare ^1,², V Rangarajan ^1,²

Aim: One of the most attractive research areas in medical imaging today is radiomics, particularly for clinical oncology. It could be challenging to integrate radiomics into clinical practice. A big hurdle towards clinical implementation is the unknowability of the robustness of the extracted radiomic features. It is necessary to evaluate feature robustness before using novel quantitative imaging biomarkers in clinical practice. Variability introduced during image preprocessing may lead to significant difference in the extracted radiomic features. This study aims to assess reproducibility of radiomic features by changing bin width parameter and voxel resampling.

Materials and Methods: 50 patients each of non-small-cell lung cancer (NSCLC) and colorectal cancer who underwent pretreatment whole-body PET/CT scans were included in this study. The gross tumor volume was delineated by a 15-years experienced medical physicist on trans-axial CT images using Philips IntelliSpaceDiscovery workstation and saved as RTSTRUCT. The radiomic features were extracted using our in-house developed PyRadGUI toolkit. The reproducibility of radiomic features were assessed by changing preprocessing parameters like voxel size and binwidth. In the first part of study, the bin width was changed to 5, 10, 15, 25, and 50 keeping the fixed voxel size of 2 × 2 ×2 mm³ and fixed sigma values as 1, 2, 3 mm (LoG). In second part, the voxel size was changed to 1 × 1 × 1 mm³, 2 × 2 × 2 mm³, 3 × 3 × 3 mm³and 4 × 4 × 4 mm³ keeping the fixed binwidth of 25 and the sigma values as 1, 2, 3 mm (LoG). Stability of radiomic features was assessed using Intra-class correlation coefficient (ICC3) of the psych package of R-software. Features were graded based on the ICC3 value as excellent: (ICC≥0.90), good: (0.9 >ICC ≥0.75), moderate: (0.75>ICC ≥0.5), and poor: ICC<0.5.

Results: In the first part of the study, 94%(1029/1093) features showed excellent correlation (ICC≥0.9) in both the cohorts. Whereas in second part of the study 15% (160/1093) features showed excellent correlation (ICC≥0.9) in both the cohorts.

Conclusion: Our study demonstrates that some of the radiomic features were highly reproducible in both disease cohorts. This shows that the feature had minimal effect on the pre-processing step and this set of features can be used for prognostic modeling. The effect of gray-level discretization and voxel resampling on the prognostic value of radiomic features has not yet been studied and requires more investigation.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 32: Correlation amongst radiomic features extracted from T₁ and T₂ weighted image-sequences of chondrosarcoma cases

Akhilesh Tripathi ¹, Biprojit Nath ¹, Ashish Kumar Jha ^1,^2,³, Sneha Mithun ^1,^2,³, Shreyash Panchal ^1,², Grace M Mehta ¹, Umeshkumar B Sherkhane ^1,^2,³, Vinay Jaiswar ¹, Prakash Nayak ^2,⁴, Nilendu Purandare ^1,⁴, Ajay Puri ^2,⁴, V Rangarajan ^1,⁴

Aim: Chondrosarcomas are malignant cartilaginous tumors that account for approximately 25% of all primary malignant bone tumors. These tumors usually have a bright signal intensity on T₂ weighted images and low or intermediate signal intensity on T₁-weighted images. The aim is to find out correlation amongst radiomic features extracted from T₁ and T₂ weighted image-sequences in chondrosarcoma cases.

Materials and Methods: This study was approved as a retrospective study by the Institute Ethics Committee (IEC) of our hospital. A total of 48 patients' pre-treatment MR images of Chondrosarcoma disease were used for this study. Manual delineation was performed by an experienced radiologist on T₁ and T₂ weighted images on 3D-Slicer (version 5.1.0). In this case, NRRDs were generated for Image and label. Radiomic Features were extracted using 3D-Slicer. A total of 1130 features were extracted on the same platform which includes all classes of features: Intensity-based features, shape-based features and texture-based features, LoG and wavelet features. For analysing the feature set ICC3 was used. It was calculated using a script in R. For selecting the best correlating features, the features expressing ICC greater than 0.9 were considered excellent features, those in the range of 0.75<ICC<0.9 were considered good features, features in the range of 0.50<ICC<0.75 were considered moderately correlating while that in the range of ICC<0.50 were considered poor correlation.

Results: A total of 97/1130 features (8.588%) exhibited excellent correlation (ICC>0.9), 179 features (15.84%) presented good correlation (0.75<ICC<0.9), 592 features (52.38%) showed moderate correlation (0.50<ICC<0.75). The remaining 261 features (23.09%) showed poor correlation (ICC<0.50).

Conclusion: It was found that 97 features showed excellent correlation amongst the two sets of MR images which may be considered redundant features while considering for the prediction model development.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 33: Comparison of MIRDcalc and OLINDA EXM 2.0 organ-absorbed dose results for radionuclide therapy patients

Acsah Konuparamban ¹, Tusharkanta Srichandan ^1,², Ashish Kumar Jha ^1,^2,³, Sneha Mithun ^1,^2,³, Pooja ¹, Dwivedi ^2,⁴, Nilendu Purandare ^1,², V Rangarajan ^1,^2,⁴

Aim: Targeted radionuclide therapy in Nuclear Medicine using ¹⁷⁷Lu- labelled radiotracers have been evolving in the recent decades. ¹⁷⁷Lu is a theragnostic radionuclide known to successfully tag various entities like peptide (eg. DOTATATE), antigen (eg. PSMA-617) and antibodies (eg. Trastuzumab). However, the normal distribution of ¹⁷⁷Lu causes the irradiation of non-target organs and healthy tissues along with the targeted tumours. To quantify the effect of radiation in each organ, absorbed dose estimation is performed. Various softwares, like MIRDcalc and OLINDA EXM 2.0 are used for this. In this study we aim to compare organ dosimetry results between these two softwares.

Materials and Methods: The data from patients who underwent ¹⁷⁷Lu- DOTATATE (30 patients) and ¹⁷⁷Lu- Trastuzumab (16 patients) therapies were taken for this study. The average activity administered was 200mCi for ¹⁷⁷Lu- DOTATATE study while that for ¹⁷⁷Lu- Trastuzumab therapy was 95mCi. The normalized cumulated activity was determined using GE Dosimetry Toolkit. Absorbed dose to the major organs like kidneys, liver, spleen and lung were calculated using both MIRDcalc and OLINDA EXM 2.0 softwares. The percentage difference between the results from both softwares were calculated by the following formula:

graphic file with name IJNM-37-15-g003.jpg

Where a= Absorbed dose from MIRDcalc

b = Absorbed dose from OLINDA EXM 2.0

Results: The absorbed dose per unit activity in kidneys, liver, spleen and lung were calculated using both softwares and recorded in Table 1. The average percentage difference between MIRDcalc and OLINDA EXM 2.0 for kidneys, liver, spleen and lungs are 5.37%, 2.31%, 2.87% and 77.38%respectively for ¹⁷⁷Lu-DOTATATE study and 0.33%, 0.83%, 17.75%, 85.37% respectively for ¹⁷⁷Lu-Trastuzumab study as shown in Table 2.

Table 2.

Table showing the percentage difference between MIRDcalc and OLINDA EXM 2.0 for each organ and radiopharmaceutical.

Organs/Radiopharmaceutical	¹⁷⁷Lu-DOTATATE	¹⁷⁷Lu-Trastuzumab
Kidney	5.37%	0.33%
Liver	2.31%	0.83%
Spleen	2.87%	17.75%
Lungs	77.38%	85.37%

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Conclusion: From this study, it was observed that the absorbed dose results are slightly higher for OLINDA EXM 2.0 than MIRDcalc. The high difference in the results for lung may be due to the fact that MIRDcalc does not consider the mass of lung for individual patients whereas OLINDA EXM 2.0 does.

Table 1.

Table showing the absorbed dose per unit activity between MIRDcalc and OLINDA EXM 2.0 for each organ and radiopharmaceutical.

Organs	¹⁷⁷Lu-DOTATATE		¹⁷⁷Lu-Trastuzumab
Organs	MIRD (mSv/MBq)	OLINDA (mSv/MBq)	MIRD (mSv/MBq)	OLINDA (mSv/MBq)
Kidney	0.30	0.28	0.818	0.821
Liver	0.126	0.129	2.065	2.082
Spleen	0.427	0.439	0.476	1.185
Lungs	0.025	0.011	0.605	0.506

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Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 34: Dosimetry of ^99mTc-DMSA and ^99mTc-DTPA studies in the paediatric patients

Shubham Ghag ¹, Acsah Konuparamban ¹, Ashish Kumar Jha ^1,^2,³, Sneha Mithun ^1,^2,³, Nilendu Purandare ^1,², V Rangarajan ^1,²

Introduction: The ^99mTc-DTPA imaging is used to assess the renal clearance and ^99mTc- DMSA is used to identify renal cortical scars caused due to obstruction or infection. Often both the tests are performed to assess the recurrent Urinary tract infection in children. Therefore, it is imperative to estimate the absorbed dose to the critical organ and the subsequent whole-body dose to the patient. This study aims to calculate the equivalent dose to the critical organ and effective dose to the patient using Society of Nuclear Medicine and Molecular Imaging (SNMMI) radiation dose tool.

Materials and Methods: A total data of 18 paediatric patients ranging from 1-10 years of age, who underwent both these scans were selected for this study. For estimation of dose delivered to the patient, the Radiation Dose Tool version 4.1 provided by SNMMI was used. The name of examination, age and injected activity details were inserted into the tool and results were obtained according to the International Commission for Radiation Protection (ICRP) - 128 (2015) dosimetry table.

Results: The average weight of the selected 18 patients was 15.61±4.42 kg. The average injected activity for ^99mTc- DMSA and ^99mTc-DTPA was 2.84±0.58mCi and 2.99±0.53mCi, respectively. The average equivalent dose to the critical organ due to ^99mTc- DMSA and ^99mTc-DTPA were found to be 42.48±8.72 mGy and 10.92±1.78 mGy respectively. The whole-body effective dose was estimated to be 2.08±0.40 mSv due to ^99mTc- DMSA, while that due to ^99mTc-DTPA was 1.00±0.14 mSv. The average total effective dose for both studies was 3.08±0.45 mSv Table 1.

Conclusion: Our study suggests that the patients receive two times the effective dose from 99mTc-DMSA when compared with that of 99mTc-DTPA. Equivalent dose to the critical organ were also found to be four times more from 99mTc- DMSA when compared with that of 99mTc-DTPA.

Table 1.

Activity and absorbed dose details for ^99mTc- DMSA and ^99mTc-DTPA radiopharmaceutical

Radiopharmaceutical	^99mTc-DMSA	^99mTc-DTPA
Average injected activity (mCi)	2.84±0.58	2.99±0.53
Average equivalent dose (mGy)	42.48±8.72	10.92±1.78
Average effective dose (mSv)	2.08±0.40	1.00±0.14

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Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 35: Evaluation of effective dose in patients administered with gallium labeled radiopharmaceuticals

Tusharkanta Srichandan ^1,², Acsah Konuparamban ¹, Ashish Kumar Jha ^1,^2,³, Sneha Mithun ^1,^2,³, Pooja Dwivedi ^2,⁴, Nilendu Purandare ^1,², V Rangarajan ^1,^2,⁴

Introduction: The ⁶⁸Ga-DOTANOC study is performed for the primary assessment and follow-up of NET patients. ⁶⁸Ga-DOTANOC accumulates in normal organ like spleen, kidneys, adrenal glands, liver, stomach, small intestine and results in significant radiation exposure to these organs. Therefore, assessment of overall radiation detriment to the body is essential in terms of radiation protection for the patients undergoing this procedure. In this study, we aim to evaluate effective dose in patients administered with ⁶⁸Ga-DOTANOC.

Methodology: Study included 5 patients' who underwent ⁶⁸Ga-DOTANOC multipoint imaging in our department. Mean age and weight of the patients were 47±7.7 years and 70±14kg respectively. Whole-body PET/CT imaging was performed at 0.5, 1 and 2h post injection on Gemini TF PET/CT scanner (Philips Medical Systems). Whole body activity was estimated by using VCAR software installed on Advantage Workstation, GE Healthcare. Time-Activity Curve (TAC) was generated from activity at different time points and Normalised Cumulated Activity (NCA) was calculated by integrating the TAC curve. Mean Dose per unit Activity (DpA) and total effective dose were estimated using OLINDA/EXM 2.0 software.

Results: Mean administered activity to the patient was found to be 65.34±12.43MBq. The mean DpA of the whole body for patients administered with ⁶⁸Ga-DOTANOC using OLINDA/EXM 2.0 software was found to be 0.015±0.002mSv/MBq. The calculated effective dose for this patient was 0.99±0.23mSv.

Conclusion: We successfully performed the ⁶⁸Ga-DOTANOC dosimetry and calculated the effective dose. The estimated effective dose for patients administered with ⁶⁸Ga-DOTANOC was found to be in agreement with other studies.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Other 36: Evaluation of imaging application of ¹⁸F-sodium fluoride positron emission tomography of assessment of condylar hyperplasia

Zeel Soni ¹

Introduction: Condylar hyperplasia (CH) is a rare disorder characterized by excessive bone growth that usually presents unilaterally, resulting in facial asymmetry. In this study we compared SUVmax of affected condyle to normal condyle in CH cases.

Aims and Objectives:

To correlate SUVmax of 18F-NaF PET-CT between affected condyle to normal condyle of U/L condylar hyperplasia and correlation between affected condyles of B/L CH to ramus of mandible
To assess the joint destruction in patients with condylar hyperplasia
To assess correlation of PET/CT findings (SUVmax) with clinical variables of condylar hyperplasia.

Methodology: Retrospective cum prospective observational study with duration of 3 years. More than 18 years of either sex suspected or diagnosed cases of Condylar Hyperplasia were recruited. We included various clinical variables (eg, duration of illness, facial asymmetry, protrusion of chin, midline shift, C/L crossbite). SUVmax analysis and visual assessment of affected & normal condyles are the major parameters for the study.

Results: Study included 34 patients with mean age of 23.03 with male: female ration of 2.3:1. Correlation between clinical variables with SUVmax on the scan found to be statistically significant, which includes TMJ destruction (P value - 0.006), Pain at TMJ joint (P-value - 0.000), Protrusion of Chin (P-value - 0.001) and Midline Shift (P-value =0.009). Moreover, in severity of disease (more than 2 symptoms) correlated with SUVmax and found statically significant (P-value ℒ0.000).

Conclusion: We concluded that TM joint destruction can be effectively assessed by SUVmax when compared with PET/CT. We also found that majority of the clinical variablesincluded in our study found to be significantly associated with condylar hyperplasia when compared SUVmax.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Others 37: Study of distribution of brown adipose tissue in PET scans of oncological versus non oncological cases

Anurag Jain ¹, Abhishek Mahto ¹, Nidhi Sharma ¹, Harkirat Singh ¹

Introduction: Brown adipose tissue (BAT) has thermogenic potential. For its activation, cold exposure is considered a critical factor though other determinants have also been reported. The purpose of this study was to assess the relationship between neoplastic (Oncological) or infective/ inflammatory (Non-oncological) status and BAT activity by 2-deoxy-2-[18F]fluoro-D-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) in patients from Indian population coming for 18F FDG PET CT, where the influence of outdoor temperature has variations.

Methods: A retrospective study was done on 25 PET Scans (n=25). The scans were studied for distribution of BAT in the body. The distribution of BAT was compared between the scans of Oncological cases and Non oncological cases. The distribution of activated BAT was compared between patients with inflammatory/ infective disease and cancer patient.

Results: The distribution of BAT was found more in few areas like

BAT found between anterior neck muscles and supraclavicular fossa in all cases irrespective of Oncological / Non oncological status
More around solid organs in scans of Oncological patients.

The Tests of Significance was performed to see if the finding is significant or not. P value calculated was < 0.0001. Since P value is < 0.05, the finding is significant suggesting distribution of BAT more around solid organs in Oncological cases compare to Non oncological cases.

Conclusions: Neoplastic or infective/inflammatory status is not a critical determinant of BAT activity in Indian population.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Category: Others: Therapy 1: (¹⁷⁷Lu) Lu-FAPi dimer therapy in radioiodine-resistant thyroid cancers

Sanjana Ballal ¹, Madhav P Yadav ¹, Frank Roesch ¹, Shweta Rajput ¹, Euy Sung Moon ¹, Marcel Martin ¹, Shipra Agarwal ², Madhavi Tripathi ¹, Ranjit Kumar Sahoo ³, Chandrasekhar Bal ¹

Purpose: This prospective study aimed to assess the efficacy [¹⁷⁷Lu]Lu-FAPi dimer therapy as a salvage treatment option in radioiodine-resistant thyroid cancer (R-R TC) patients with both follicular and parafollicular cell origin.

Materials and Methods: Twenty-nine patients (mean age: 50 years, range: 32-65y, males-14, females-15) with metastatic R-R TC were prospectively recruited after disease progression was observed on standard treatments, including radioiodine therapy, tyrosine kinase inhibitors such as sorafenib, lenvatinib, vandetanib, and ¹⁷⁷Lu-PRRT. Twenty-four patients had TC from follicular origin and five patients has medullary thyroid cancer. All patients underwent screening with [⁶⁸Ga]Ga-DOTA.SA.FAPi, [¹⁸F]F-FDG, and [⁶⁸Ga]Ga-DOTANOC PET/CT scans to confirm the expression of the cancer with different radiotracers. Patients received slow intravenous [¹⁷⁷Lu]Lu-FAPi dimer injection of approximately 4 to 5.5 GBq/cycle at six-to-eight-weekly intervals. The primary endpoint was assessment of biochemical response by thyroglobulin assessment. Secondary endpoints included safety assessment according to the National Cancer Institute's Common Toxicity Criteria V5.0.

Results: Between October 2020 to March 2022, in a median follow up of 12 months, a total of 79 [¹⁷⁷Lu]Lu-FAPi dimer therapy cycles (median 3 cycles/patient; range 2-7) were administered. The median administered cumulative radioactivity was 11.1 GBq (range: 7.4 to 25.5 GBq) [4 ℒ5.5 GBq/cycle]. Except for three, all patients are alive and have experienced a decline in the thyroglobulin (Tg) [baseline Tg: 1795.5 ng/mL vs. post-treatment: 574.5 ng/mL, P<0.0001] and calcitonin (baseline calcitonin: 5789 pg/mL vs. post-treatment: 2647pg/mL, P-0.052) values for the baseline. None of the patients experienced grade III/IV hematological, renal, or hepatotoxicity.

Conclusion: [¹⁷⁷Lu] Lu-FAPi dimer therapy is a promising salvage treatment option for the treatment of aggressive R-R TC patients.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Therapy 2: (⁶⁸Ga) Ga-DOTA.SA.FAPi guided (¹⁷⁷Lu) Lu-FAPi dimer therapy in low SSTR expressing, FDG positive neuroendocrine tumors

Sanjana Ballal ¹, Madhav Prasad Yadav ¹, Frank Rösch ¹, Marcel Martin ¹, Madhavi Tripathi ¹, Ranjit Kumar Sahoo ², Chandrasekhar Bal ¹

Purpose: The study aimed to report the first clinical experience with [¹⁷⁷Lu]Lu- FAPi dimer therapy as a salvage treatment option for advanced stage, minimally SSTR expressing neuroendocrine tumours.

Materials and Methods: Histologically confirmed NET patients initially underwent [⁶⁸Ga] Ga-DOTANOC, [¹⁸F]F-FDG, and [⁶⁸Ga]Ga-DOTA.SA.FAPi PET/CT scans. Patients with minimal SSTR expression but avid FDG and [⁶⁸Ga]Ga-DOTA.SA.FAPi uptake were enrolled for [¹⁷⁷Lu]Lu-FAPi dimer therapy. Once deemed eligible for treatment, they received intravenous [¹⁷⁷Lu] Lu-FAPi dimer of approximately 4 GBq/cycle at eight-weekly intervals. The primary endpoint included biochemical (plasma chromogranin A (CgA or serum(s) calcitonin) and molecular tumour response assessment. Secondary endpoints included safety assessment by the National Cancer Institute's Common Toxicity Criteria v5.0.

Results: Twelve patients (9 males and 3 females; mean age: 41.6 ± 15 years) with histologically confirmed NETs were prospectively recruited and treated with [¹⁷⁷Lu]Lu-FAPi dimer therapy. Twelve patients had five types of NETs: NET lung (carcinoids) in four, ovarian, appendix and colon NET one in each group, and medullary thyroid cancers in 5 patients, respectively. Between March 2021 to December 2021, in a median follow up of 6 months, a total of 31 cycles (median 2 cycles/patient; range 2-4) were administered. The mean administered cumulative radioactivity was 10 GBq (range: 200 to 400) [100 mCi/cycle]. Except for one, all patients are alive and have experienced a decline in the CgA and calcitonin values for the baseline (baseline CgA: 371.5 ng/mL vs. post-treatment: 201 ng/mL, p-0.0312); (baseline s. calcitonin: 1511 pg/mL vs. post-treatment: 1046.5 pg/mL, p-0.1250). All four patients who underwent molecular tumour response assessment demonstrated stable disease. None of the patients experienced grade III/IV haematological, kidney or hepatotoxicity from [¹⁷⁷Lu] Lu-FAPi dimer therapy.

Conclusion: The preliminary data suggest that the [¹⁷⁷Lu] Lu-FAPi dimer therapy is safe, effective, and most importantly, opens up a new avenue for the systemic treatment of aggressive NETs who cannot benefit from ¹⁷⁷Lu/⁹⁰Y/²²⁵Ac-PRRT.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Therapy 3: Automated production of ⁹⁰Y DOTA peptides using in-house developed automated synthesis module

Y R Nitin ¹, S Sahoo ¹, S Lad ¹, A Mitra ¹, M K Ray ¹, S P Kulkarni ¹

Introduction: 90Y-DOTA-TATE is used as a therapeutic radiopharmaceutical for treatment of neuroendocrine tumors. To reduce the exposure of personnel to radiation hazard, the present work demonstrates use of an automated synthesis module for the final radiopharmaceutical preparation in conformity with current good manufacturing practices.

Materials and Methods: (a) Hardware and Software: The Module consists of chemically resistant solenoid valves, reagent and reaction vials Figure 1, Peristaltic Pump, heater, transfer tubing and Radiation detectors. The C# GUI provides a user-friendly interface to and monitor various reaction parameters such as radioactivity and reaction temperature.

(b) Methods: The synthesis steps involve transfer of 90Y-Acetate to Reaction Vial through a peristaltic pump followed by addition of 2.5 mL of 0.2M CH3COONH4 buffer (pH '~ 5.5), and DOTATATE to reaction Vial. Reaction mixture was incubated at 95^oC for 35 minutes. Further, the reaction mixture is cooled to Room Temperature for 10 minutes and loaded to preconditioned tC18 column followed by washing with 2ml of saline. 90Y-DOTATATE is eluted using 50% Ethanol (0.8-1.0 ml) followed by saline. After passing the product through a 0.22micron filter it is pre-dispensed with 2,5-dihydroxybenzoic acid in saline (~ 60 mg /mL).

Results: The automated synthesis module has successfully produced around 15 batches of sterile 90Y-DOTA-TATE with over an average of 100 mCi per batch in the last one and half year.

Conclusion: These results ensured utility of module for large scale production while reducing radiation exposure to the operating personnel.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Therapy 4: P32 therapy in recurrent cystic craniopharyngioma

Rashmi Angadi ¹, John Santhakumar ¹

Objective: Cystic craniopharyngiomas are considered the most common intracranial nonglial tumor in children with the tendency for cyst formations. The aim of this study was to evaluate the effect of intracystic phosphorus 32 (P32) therapies on controlling the growth of the cystic component of craniopharyngioma.

Case Presentation: 14 yr old female had a history of headache and vomiting since birth (2004). Aggravated since 2010. CT brain plain (21.09.2012): large well defined extradural suprasellar cystic lesion more likely S/o craniophryngioma. Underwent transcranial transylvian aspiration of craniopharyngioma with omaya reservoir placement on 01.10.2012. Intracystic instillation with alpha interferon 2a injection (0.25mg-1.5lakh IU)- March 2013. On treatment with tablet thyronorm 50mgm OD and minirin spray 1 puff per day (alternate nostril). History of recurrent headache and diabetes insipidus with worsening visual disturbances since 2014. Investigations in 2018: Serum LDH: >1000U/L. MRI brain screening in 2018 showed widening of sella turcica with altered T2wt / flair hyperintense measuring 2.5 × 2.1 × 3.2 cms in sellar and suprasellar region-? Residual/ recurrence and drainage tube was noted with its tip near posterior limb of left internal capsule. Admitted in Nuclear Medicine department on 18.08.2018 and underwent intracystic instillation of samarium Phophate-32 colloidal suspension 1.2mCi. Focal area of tracer uptake in the sellar/ suprasellar region, SPECT CT images localised the region of therapeutic intervention with no evidence of tracer extravasation into the surrounding region. Advised all the medications and referred for endocrinologist, since she was to attain puberty. Follow up advised. 2021 LDH levels: 162U/L (normal value: 140-300U/L). Similar another case was treated in the same year and showed good response.

Discussion: This illustrates that Intracystic p32 therapy was an effective and almost safe procedure for the treatment of cystic component of craniopharyngioma leading to optimal patient outcome.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Therapy 5: In-house preparation of 225Ac-PSMA-617 and 225Ac-DOTATATE: An institutional review

B S Shetye ¹, S Mithun ¹, A Chouhan ¹, A R Agrawal ¹, V Rangarajan ¹

Introduction: Use of alpha emitting radionuclides as a thernostic pair of radionuclide has ushered new era in treatment of cancer. Its short range offers selective killing of cells sparing surrounding normal tissue and high LET kills malignant cell more effectively by acting at DNA level. It plays a pivotal role in treatment of patients who are resistant to conventional therapies. ²²⁵Ac is a radionuclide of choice because if it's relatively long life and favourable decay scheme. PSMA-617/DOTATATE labelled with ²²⁵Ac using bifunctional chelating agent like DOTA has shown encouraging results in the treatment of prostate cancer and neuroendocrine tumour. Aim of our study was to optimize the labeling protocol of 225-Ac-PSMA617/DOTATATE and evaluate its labeling parameters.

Materials and Methods: DOTA-PSMA-617 and DOTA-TATE acetate procured from ABX (advanced biochemical compounds, Germany) was used for labeling with ²²⁵AcCl₃. 70 to 80 KBq/kg of ²²⁵AcCl₃ was used for preparation of ²²⁵Ac-PSMA-617 (n=16). 100 KBq/Kg of ²²⁵AcCl₃ was used for preparation of ²²⁵Ac-DOTATATE (n=1). 150 μCi2 to30 μCi of ²²⁵AcCl₃ and 150 μg/150 μl of PSMA-617/DOTATATE were used for preparation of patient's doses. Labeling was carried out using phosphate buffer. Entire content was mixed slowly and transferred to a vial containing ²²⁵AcCl₃. Reaction mixture was heated at 90⁰C for 25 minutes. It was allowed to cool for 5 minutes. Product was loaded on a C-18 cartridge preconditioned with 70% ethanol followed by HPLC water. Labelled product was extracted using 2 ml of ethanol followed by HPLC water. pH, colour, appearance and radiochemical purity (RCP) of the labelled product was assessed. RCP was assessed by ITLC method using 0.1M Na-citrate as a mobile phase.

Results: Preparations of ²²⁵Ac-PSMA-617 and ²²⁵Ac-DOTATATE were clear, colourless liquid and their pH was in the range of 5-5.5. Labelledproduct was remained at the pointer of spotting (R_f = 0). Radiochemical purity of ²²⁵Ac-PSMA617 was > 96 %. RCP of ²²⁵Ac-DOTATATE was >98 %.

Conclusion: As per literature radionuclide therapy using alpha emitting radiopharmaceuticals is useful in patients who are resistant to conventional radionuclide therapy. Our in-house preparation of ²²⁵Ac-PSMA617 and ²²⁵Ac-DOTATATE showed efficient radiolabeling results. Hence, ²²⁵Ac-PSMA617 and ²²⁵Ac-DOTATATE prepared in in-house hospital based radiopharmacy can be used in treatment of Ca prostate and patient with neuro-endocrine tumour effectively.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Therapy 6: Response assessment of peptide receptor radionuclide therapy in metastatic neuroendocrine tumors: A retrospective study from tertiary care center in South India

Paladugula Lakshmi Pratyusha ¹, Nimmagadda Ajit ¹, Abubacker Zakir Ali ¹, Prathyusha Bikkina ¹, Tejonath Gadepalli ¹

Background: Neuroendocrine tumors (NET) are often metastatic or inoperable at the time of presentation, with less treatment options. Peptide receptor radionuclide therapy (PRRT) targeting the SSTR expression on these tumors, is now a part of standard of care for metastatic and inoperable NETs.

Objectives: The aim of this study were to evaluate the therapeutic response of ¹⁷⁷Lu-DOTATATE in advanced metastatic NET.

Methods: Retrospectively, medical records of NET patients, who underwent ¹⁷⁷Lu-DOTATATE therapy from February 2014 to October 2022 in our institute, were interrogated. Patients who received 2 or more cycles of PRRT were included in the study. Treatment response following PRRT was evaluated with RECIST1.1 for anatomical imaging and PERCIST 1.1 for molecular imaging.

Results: A total of 56 (32 males and 24 females) NET patients (mean age: 54.45 years SD: 11.76 years), who had undergone ¹⁷⁷Lu-DOTATATE therapy of at least 2 cycles were identified and selected for the analysis. The number of cycles received by the patients ranged from 2 to 9 (median 4). The follow-up period ranged from 3 months to 102 months (median: 46 months). The primary sites of NET in our study were predominantly pancreas (n=23/56), followed by small bowel (n=15/56), large intestine (n=5/56), lung (n=6/56), unknown primary site (n=6/56) and others (1/56). Out of 56 cases, on anatomical imaging, 21/56 (37.5%) showed partial response, 14/56 patients (25%) had stable disease and in 21/56 (37.5%) patients there was disease progression. There was no complete response seen. While on molecular imaging partial response was seen in 24/56 (42.86%), stable disease in 11/56 (19.64%) and progressive disease in 21/56 (37.5%) patients respectively. 2 patients (3.57%) were found to be expired, on follow up.

Conclusion: PRRT therapy shows a good anatomical and molecular response in patients with metastatic NET irrespective of the tumor burden, primary site and age of the patients.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Therapy 7: In-house preparation of ¹⁷⁷Lu-PSMA-617 using noncarrier added ¹⁷⁷Lu for the radionuclide therapy of prostate cancer

Manoj Kumar R Chauhan ¹, Varun Shukla ¹, M V Manikandan ¹, Jay Prakash Kumar ¹, Ritwik Sinha ¹, Ravi Kumar Chauhan ¹, Ajay Kumar ¹, Uddeshya N Jha ¹, Jennit Ittiachan ¹, Sachin Tayal ¹, Santosh Kumar Gupta ¹

Introduction: Prostate cancer (PCa) is one of the major cancers affecting men and a significant population of elderly patients in India. Lutetium-177 labelled PSMA-617 is an emerging radiopharmaceutical for targeted radionuclide therapy of prostate cancer (PCa).

Aim of the Study: was to optimise the in-house labelling of ¹⁷⁷Lu-PSMA-617 and its quality control.

Methods: Non-career added ¹⁷⁷LuCl₃ was purchased from ITG (Germany). PSMA617 peptide along with Sodium Ascorbate, Ascorbic acid and 0.1N HCl was purchased from B J madan & Co (New Delhi). Stock solution of buffer was prepared by mixing Sodium ascorbate (160 μg) and ascorbic acid (40 μg) in 15 ml of ultrapure water. PH of buffer should be in between 4-5. 100μl of PSMA peptide aliquots (1 g:3 ml, peptide-water ratio) was added in reaction vial. Then, 900μl of buffer from stock solution was added in reaction vial. 200 mCi of n.c.a ¹⁷⁷LuCl₃ was added in reaction vial and reaction vial was heated in heather bath for 25 min at 90°. The final product is passes through microfilter before injection to patients. Radiochemical purity (RCP) of final product was quantitatively analyzed by TLC Scanner. Thin-layer chromatography-silica gel (TLC-SG) plates was used as a stationary phase and it was developed with a 0.1 M Tri-Sodium Citrate dihydrate as a mobile phase.

Results: Quality of 15 batches of ¹⁷⁷Lu-PSMA was evaluated. Average yield efficiency of labelled ¹⁷⁷Lu-PSMA was 97.52%. Rf of ¹⁷⁷Lu-PSMA was 0.159 in TLC scanner.

Conclusion: The studies carried out suggest that therapeutic doses of ¹⁷⁷LuPSMA-617 could be prepared by using high specific activity, non-carrier added ¹⁷⁷Lu for the treatment of Prostate Cancer. Clinical studies demonstrated the uptake and retention of the tracer in prostate cancer lesions.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Therapy 8: Effectiveness of indigenous ⁹⁰Y-DOTATATE in duo-PRRT and non-duo-PRRT protocols in patients with bulky metastatic and locally advanced gastroenteropancreatic neuroendocrine tumours at tertiary care institute in India

Bhakti Vaidya ¹, Rahul V Parghane ¹, Sudeep Sahu ¹, Sandip Basu ¹

Background and Aim: Bulky lesions with size >5cms are quite prevalent in GEP-NETs with limited therapeutic outcome after ¹⁷⁷Lu-DOTATATE PRRT. ⁹⁰Y-DOTATATE has theoretical advantage in bulky disease but has higher toxicity than ¹⁷⁷Lu-DOTATATE. The aim of this study was to evaluate the therapeutic response, progression free survival (PFS), overall survival (OS) and clinical toxicity of ⁹⁰Y-DOTATATE (under duo-PRRT and non-duo-PRRT protocol) of GEP-NET patients.

Materials and Methods: Under duo-PRRT protocol, 2 cycles of ¹⁷⁷Lu-DOTATATE, followed by 1 cycle of ⁹⁰Y-DOTATATE, followed by 2 cycles of ¹⁷⁷Lu-DOTATATE were given in bulky locally advanced metastatic GEP-NETs and non-duo-PRRT protocol consisted of ⁹⁰Y-DOTATATE therapy after completing ¹⁷⁷Lu-DOTATATE cycles in progressive cases. Response to ⁹⁰Y-DOTATATE under both protocols were evaluated under 3 categories: (a) symptomatic (b) biochemical using (serum chromogranin A) and (c) Imaging response (RECIST 1.1 for anatomical imaging and PERCIST 1.0 for molecular imaging). The PFS and OS were determined following duo-PRRT. Acute and chronic toxicity of indigenous ⁹⁰Y-DOTATATE was assessed in both the protocols by NCI-CTCAE scale version 5.0 for hemato-toxicity, hepato-toxicity and nephro-toxicity.

Results: A total of 34 patients {21 males and 13 females (29-75years) with median age-50years} received ⁹⁰Y-DOTATATE therapy (19 under duo-PRRT, 15-non-duo-PRRT protocol) in this study. The post-duo-PRRT and non-duo-PRRT follow-up period (3-12 months), (3-29 months) after last PRRT cycle with an average follow-up of 7.5 months and 13 months respectively. Out of 19 patients, 17 (89.5%) were responders on symptomatic scale{Complete response (CR) in 4 (21.1%), partial response (PR) in 9 (47.3%), stable disease (SD) in 4 (21.1%)} and 17 (89.5%) on biochemical scale{CR in 3 (15.8%), PR in 5 (26.4%), SD in 9 (47.3%)} and 2 (10.5%) were non-responders (PD). On PERCIST 1.1, 15 (78.9%) {PR in 6 (31.6%), SD in 9 (47.3%)} and on RECIST, 17 (89.5%){Minor Response in 3 (15.8%), SD in 14 (73.7%)} were responders and nonresponders were 4 (21.1%) and 2 (10.5%) respectively. At 6 months post-duo-PRRT, 2 progressed on RECIST and expired during the duo-PRRT. Median PFS, OS not achieved. The estimated PFS, OS was 90% and 95% respectively at 12 months. In non-duo-PRRT protocol, responders on symptomatic scale were 10 (66.7%), biochemical scale 11 (73.3%), PERCIST 8 (53.3%), RECIST 11 (73.3%) and non-responders were 5 (33.3%), 4 (26.7%), 7 (46.7%) and 4 (26.7%) respectively. Median PFS achieved at 11 months, OS not achieved. Estimated OS at 30 months - 55%. Out of 34, acute toxicity of grade 1 nausea and vomiting were observed in 4 (21.05%) and 2 (10.53%) patients (duo-PRRT protocol) and in 3 (20%) and 1 (6.67%) patient (non-duo-PRRT protocol). While on follow-up post-duo-PRRT, major Grade 3/4 toxicity was not found except transient Grade 3 thrombocytopenia in 1 (5.26%). Transient Grade 2 leucocytopenia in 2 (10.5%), Grade 1 anemia and nephro-toxicity noted in 1 patient (5.26%) each. During post-non-duo-PRRT follow-up, transient grade 1 anemia and leukocytopenia in 1 (6.67%) and 2 (13.34%) respectively. No hepatoxicity noted in either of the protocols.

Conclusion: ⁹⁰Y-DOTATATE therapy in duo-PRRT and non-duo-PRRT protocol achieved significant clinical response in bulky GEP-NETs. In both protocols, disease stabilization was demonstrated in most of the GEP-NETs with longer PFS and OS. No major Grade 3 / 4 toxicity except thrombocytopenia (duo-PRRT) was found during the follow-up period. Hence this approach may be more effective than conventional monotherapy (¹⁷⁷Lu-DOTATATE) for treating bulky locally advanced metastatic and progressive GEP-NET.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Therapy 9: Impact of coexisting lymphocytic thyroiditis in differentiated thyroid carcinoma

P Pradap ¹, Harish Goyal ¹

Background: Differentiated thyroid cancer (DTC) is routinely treated by thyroidectomy followed by radioiodine ablation and generally has a good prognosis. Hashimoto's thyroiditis (HT) and lymphocytic infiltration with DTC in surgical specimens may have an impact on the outcome as it may affect radioiodine concentration in the remnant thyroid tissue. We aim to study the clinicopathological, biochemical, and low-dose radioiodine scan finding in a post-operative setting and on subsequent follow-ups.

Materials and Methods: We retrospectively analyzed 20 patients with histopathologically proven DTC with features of thyroiditis (Hashimoto's or lymphocytic thyroiditis) in the post-operative biopsy specimen. Other attributes, such as tumor size, multi-centricity (unifocal/multifocal), and extrathyroidal extension, along with other parameters also taken for risk stratification. We obtain the serum thyroglobulin (Tg) and anti-thyroglobulin antibody level, and serum TSH level before the diagnostic radioiodine scan. All patients underwent a diagnostic radioiodine (I-131) whole-body scan, and eighteen patients received radioiodine therapy for remnant ablation. All patients underwent follow-up low-dose radioiodine scans after 6 to 8 months and obtained biochemical parameters (Tg and anti-Tg).

Results: From the analysis of 20 patients (14F; 6M and mean age 37 ± 15 years) of DTC with coexisting thyroiditis features in a post-operative biopsy specimen. The mean tumor size was 3.1 ± 1.01cm, and 12 out of twenty had a unifocal tumor. The extrathyroidal extension was noticed in only two patients. Eighteen patients were classified as low risk based on ATA risk stratification. On post-surgery diagnostic radioiodine scan, nine patients manifested minimal tracer uptake in the thyroid bed region, and another nine patients with focal and significant tracer uptake in the thyroid bed region; these patients received a therapeutic dose of radioiodine (I-131) for remnant ablation within 48 hours of the scan. Two patients who presented with no significant abnormal tracer uptake in the neck or elsewhere in the body were labeled as very low risk and did not receive a therapeutic dose of radioiodine. On follow-up, there was a significant reduction in the surrogate marker anti-Tg level (P value <0.05) noticed. There is no significant correlation noticed between pre-therapeutic Anti Tg level and Radioiodine Concentration.

Conclusion: Coexisting thyroiditis with DTC seems to be associated with better clinical outcomes; however, the impact of thyroiditis on radioiodine concentration is yet to be established.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Therapy 10: Can volumetric parameters predict outcome in metastatic castration resistant carcinoma prostrate patients treated with Lu-177 PSMA therapy?

P Singh ¹, Y Khandelwal ¹, B Jain ¹, V Mishra ¹, M Ora ¹, A H Nazar ¹

Introduction: Prostrate cancer is the second most frequent malignancy worldwide with a very high mortality rate. It is well known that a high volume of disease is a negative prognostic factor for patients with prostate cancer.¹⁷⁷Lu-PSMA-617 is a recently approved therapeutic option for end-stage prostate cancer patients. Preliminary data suggest that PSMA PET-derived total tumor volume (PSMA-TV) changes can be employed to monitor treatment response to therapy and detect recurrences in early patients with prostate cancer.

Aim: The current study is planned to predict overall survival in patients treated with ¹⁷⁷Lu-PSMA therapy utilizing volumetric parameters in ⁶⁸Ga-PSMA PET/CT acquired at baseline and after three cycles of ¹⁷⁷Lu-PSMA therapy.

Materials and Methods: In this retrospective single-center study, after obtaining ethical approval, 20 patients of metastatic castration resistant carcinoma prostrate (mCRPC) were included in the study by convenient sampling. The baseline details like age, Gleason's score, biochemical parameters and PSA level were noted. All patients underwent PSMA-labeled PET scans at baseline and post-therapy. The baseline and post-therapy SUV max, SUV mean, SUV peak, PSMA-derived tumor volume (PSMA-TV) and total lesion PSMA (TL-PSMA) were calculated for each patient and used for analysis. Change in all PET parameters was calculated as ΔPET= (PET2-PET1)/PET1. Response in PSMA-TV was assumed when a decline > 30% was present. Data were entered using Microsoft excel and analyzed using SPSS version 23.

Results: The mean age of the study participants was 69.75+/-7.52 years and the median Gleason's score was 9. The volumetric parameters SUVmax, PSMA-TV, Total SUVxVolume, and Total SUV showed a significant decrease post-therapy. PSA and Gleason's scores were significantly associated with the volumetric parameters of PSMA PET. Baseline PSMA-TV was a statistically significant prognosticator of OS (HR = 0.904 95%CI, 0.851-0.959, p=0.011). Reduction in PSMA-TV was not a statistically significant positive prognosticator of OS (HR=01.050 95%CI 0.946-1.165, p=0.352). Likewise, there was no statistical difference in survival time comparing patients with PSMA-TV response to those without response (13.2 vs. 15.6 months).

Conclusion: PSMA-derived volumetric parameters provide a quantitative imaging biomarker for whole-body tumor burden. It might be a new PET-based metric to predict response to radioligand therapy. PSMA-TV was a positive prognosticator of OS only in patients with high PSMA expression. This might indicate that patients with low PSMA expression may not be suited for assessing PSMA-TV reduction. Further studies investigating the correlation of PSMA-TV with low PSMA expression and a larger cohort of patients is warranted.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Therapy 11: Thyroid carcinoma with functioning metastases – Can radioiodine be given in a state of suppressed thyroid-stimulating hormone? – A case report

Brinda Ravichandran ¹, R Vishnu Kumar ¹, Nandini Pandit ¹

Introduction: Differentiated thyroid carcinomas are known to be associated with a good prognosis. The mainstay of treatment is surgical resection followed by radioiodine therapy. Hypothyroid state is essential for adequate follicular expression of sodium iodide symporter and to facilitate the uptake of Radioiodine. Patients with functioning metastases wherein the metastatic lesions actively produce thyroid hormones pose a challenge in administering Radioiodine as their TSH is always suppressed.

Case Discussion: Here we present a 34-year female who presented with diffuse thyroid swelling. She underwent total thyroidectomy and central compartment lymph node dissection. Post-operative histopathology was infiltrative-variant of follicular thyroid carcinoma. Diagnostic-I-131 whole body scan revealed residual lesion in the thyroid bed, bilateral lung metastases, left renal metastasis, and multiple skeletal metastases. She received two cycles of I-131 therapy with 192 mCi and 170 mCi, 6 months apart. She was on suppressive doses of Levothyroxine. She later developed features of thyrotoxicosis, and Levothyroxine was stopped. She was on antithyroid medications to control her symptoms. There was a challenge at this stage as to whether Radioiodine could be given when TSH is suppressed. We did a follow-up scan with low dose of I-131, and it showed significant I-131 uptake in all of the pre-existing lesions. She received three more cycles of I-131 therapy and is currently hypothyroid.

Conclusion: It is still possible to administer I-131 in patients with functioning metastases with suppressed TSH because long-acting thyroid-stimulating antibodies facilitate adequate uptake.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Therapy 12: Long term outcome of differentiated thyroid cancer patients with skeletal metastases – A retrospective cohort study

K V Sivasankar ¹, Madhav P Yadhav ¹, Sanjana Ballal ¹, Madhavi Tripathi ¹, Chandrasekhar Bal ¹

Introduction: Skeletal metastases in patients with differentiated thyroid cancer (DTC) are associated with poor prognosis. The objective was to determine survival outcomes and to identify the prognostic factors.

Materials and Methods: This was a retrospective cohort study done at a tertiary care institution. On analysis of electronic and physical database from January 1990-June 2020, 10,124 DTC patients with 646 (6.4%) patients having skeletal metastases were found. 489 patients with ≥12 months follow-up were included in this analysis. Ninety-six percent of patients had thyroidectomy followed by repeated administration of radioiodine therapy for skeletal metastases. All patients were on oral suppressive levothyroxine tablets; doses adjusted on the basis of serum TSH. The external beam radiotherapy (EBRT) was used when indicated, and lately, oral tyrosine kinase inhibitors in selected cases. The main outcome measures were overall survival (OS), progression-free survival (PFS), and prognostic factors.

Results: There were 347 (71%) females and 324 (66%) had follicular carcinoma thyroid. 333 patients (68.1%) received ≤37GBq I-131cumulative activity (group-1), 156 patients (31.9%) received >37GBq cumulative RAI activity (group-2). The median cumulative activity of I-131 administered was 29.6GBq (IQR 18.5-44.2GBq). Median follow-up was 78 (IQR: 37 – 153) months. Out of 136 (27.8%) patients with initial remission, subsequently 58 (42.6%) patients developed recurrent disease, with the median time to recurrence of 60 (IQR: 24-102) months. Eventually, radioiodine refractoriness developed in 69.3% patients. Median OS and PFS were 74 (IQR: 36– 151) and 48 (IQR: 20-93) months, respectively. The 5-, 10-, 15- and 20-year estimated overall survival probabilities were 55.7%, 28.4%, 14% and 8.3%, respectively. The median OS for ≤37Gbq group and >37GBq group were 51 (IQR- 20-132) and 90 (IQR- 60-168 months) respectively. The median PFS for ≤37Gbq group and >37GBq group were 45 (IQR- 20-96) and 53 (IQR- 22-86) months respectively. On multivariate analysis, age (<55 years), female gender, cumulative I-131 activity (>37GBq) and EBRT were favourably associated with OS; no factors were associated with PFS. However, cumulative activity exceeding 37GBq resulted in more adverse events, particularly bone marrow suppression (14/17 patients). The limitations of the study include retrospective study design, selection bias of a tertiary referral centre, and individualized non-radioiodine treatment methods.

Conclusion: Though patients who received >37Gbq had better survival outcomes, it was associated with significant adverse events in the form of bone marrow suppression. Thus, cumulative activity up to 37GBq could be administered with acceptable toxicity to skeletal metastases patients. In radioiodine refractory DTC patients, TKI's and newer treatment options like FAPI based agents should be considered.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Therapy 13: Adaptable excretion of PSMA in CKD patients: What has it got to tell us??

P Santhosh Kumar ¹, R Kumar ¹, S K Taywade ¹

Introduction: Radioligands targeting the prostate specific membrane antigen (PSMA), are used in imaging and treatment of metastatic carcinoma prostate. These radioligands are excreted predominantly via kidneys with variable excretion through biliary system. Biliary excretion is mainly due to the lipophilicity of the radioligand. Hence, kidneys represent the critical organ for PSMA therapy and cumulative administered activity is determined accordingly. The absorbed dose for any organ would depend upon the uptake of PSMA. There are many factors that affect the renal uptake of PSMA. We, here, present our preliminary observations about renal function status and variation in renal uptake & excretion in patients who underwent whole body 99mTc-HYNIC PSMA imaging for carcinoma prostate.

Materials and Methods: We retrospectively reviewed patients who underwent 99mTc-HYNIC PSMA imaging in our department. 28 carcinoma prostate patients, whose renal function status (Serum Creatinine) at the time of scan was available, were included in the study. EGFR were obtained using the CKD-EPI Creatinine Equation (2021). Planar whole-body PSMA images were visually assessed for the radiotracer uptake in the kidneys and other abdominal organs. We also applied a method of semi-quantitative analysis. Here, geometric mean counts of the kidneys were obtained through their corresponding ROIs. Counts were also obtained from the abdomen-ROI which included from the upper border of liver till the pelvis, excluding the urinary bladder and metastatic lesions, if any. Thus, by this method, we were able to calculate the relative uptake in the kidneys and other extrarenal organs (includes liver, gall bladder, spleen and GI tract) of the abdomen.

Results: On visual analysis it is noted that, in patients with normal renal function (n=24), predominant PSMA uptake is noted in the kidneys than the rest of the abdominal organs. Whereas in patients with compromised renal function (eGFR<60ml/min/1.73m², n=4), visually, there is decrease in renal PSMA uptake with significant increase in bowel uptake. On semi-quantitative analysis, it is noted that there is variable significantly higher relative uptake renal ratios (Mean=34.4) in patients with preserved eGFR. In CKD patients, there is significant fall in the relative renal uptake ratios (Mean=20.8) with respect to the abdominal counts obtained as defined. This reflects the increased PSMA uptake in other abdominal organs, predominantly bowel, probably due to hepatobiliary excretion of PSMA in such patients.

Conclusion: Our preliminary experience in CKD patients suggests altered distribution of Tc99m-HYNIC PSMA with respect to the renal function. The reduced renal excretion and the predominant alternate hepatobiliary excretion in such patients may lead to decrease in overall renal radiation exposure. However, these observations need validation through dedicated dosimetry studies with a large sample size.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Therapy 14: Comparison of 1110 MBq versus 1850 MBq radioactive iodine ablation in low and intermediate-risk patients with differentiated thyroid carcinoma post total thyroidectomy

Jemimah Nayar ¹, Julie Hephzibah ¹, Saumya Sara Sunny ¹, M J Paul ¹, Nylla Shanthly ¹, David Mathew ¹

Introduction: Papillary carcinoma and its variants such as Follicular variant of papillary thyroid carcinoma (PTC) is a differentiated thyroid malignancy with good response to therapy. The present standard of care for 'low and intermediate risk' PTC is total thyroidectomy followed by radioactive iodine ablation (RAIA) for residual disease. The routine institutional policy before 2018, was to administer a dose of 1850 MBq. However, recent evidence indicated that 1110 MBq may be just as effective with the added benefits of reduced cumulative dose of radiation, administration on an outpatient basis, and being cost-effective. From 2018 onwards, a dose of 1110 MBq was administered to this group of patients. With this study, we seek to compare the treatment outcomes in both these groups.

Materials and Methods: Bidirectional cohort study where retrospective and prospective analysis of patients, post total thyroidectomy categorized into 'low and intermediate risk' differentiated thyroid carcinoma and referred to Nuclear Medicine Department for RAIA from 2013 to 2022 was done. The scintigraphic and biochemical findings were analyzed and the final outcome was recorded and compared in both groups.

Results: A total of 162 patients were included in the study. There were 90 patients in the 1850 MBq group and 72 in the 1110 MBq group. The patients were followed up every 6 months for a minimum of 2 years. A negative total whole-body scan (TWBS) and serum thyroglobulin of <1 ng/dl was considered an excellent response to therapy. At 6 months, 74.6% of the patients treated with 1850 MBq dose and 76.7% of the patients treated with 1110 MBq dose showed an excellent response, with no statistical difference in response (p = 0.779). One patient from the 1850 MBq group required repeat treatment with 1850 MBq and 2 patients from the 1110 MBq group required repeat treatment. One was given a dose 1850 MBq whereas the other patient received a dose of 1110 MBq. At 1 year follow-up, 86.2% of the patients treated with 1850 MBq dose and 82% of the patients treated with 1110 MBq dose showed an excellent response, with no statistical difference in response (p = 0.513). At 2 year follow-up, 84.4% of the patients treated with 1850 MBq dose and 94.5% of the patients treated with 1110 MBq dose showed an excellent response, with no statistical difference in response (p = 0.121).

Conclusion: For low- and moderate-risk diseases, doses of 1110 MBq and 1850 MBq were similarly efficacious with similar treatment outcomes. Therefore, in comparison to 1850 MBq radioiodine activity, a modest dose of 1100 MBq radioiodine activity is sufficient for thyroid residual ablation with lower cost, fewer common side effects, lower radiation exposure, and a shorter hospital stay.

Indian J Nucl Med. 2022 Dec;37(Suppl 1):S15–S78.

Therapy 15: Therapeutic outcomes of¹³¹I-MIBG (Meta-Iodo-Benzyl-Guanidine) therapy in different types of malignancy from a tertiary center of India – A retrospective analysis

T Kishan Subudhi ¹, John Pathak ¹, Jasim Jaleel ¹, Dikhra Khan ¹, Sambit Sagar ¹, C S Bal ¹

Background and Objectives: ¹³¹I-MIBG is used for both diagnosis and treatment of different types of malignancy that originates from neural crest. It is a guanithidine analogue that concentrates in different types of malignancy. Here we analyzed treatment outcomes of patients of different types of malignancy referred for MIBG therapy in our institute.

Materials and Methods: All the patients received ¹³¹I-MIBG therapy in our institute from 2003 to 2019 with different malignancies were included in the study. Then the types of malignancy and their outcomes are analyzed in terms of stable disease (SD), partial response (PR), progressive disease (PD) and complete response (CR). Those patients received only one cycle and never followed up with the clinic were categorized as loss to follow up (LTF) and their response could not be assessed.

Results: Total 80 patients were received ¹³¹I-MIBG therapy in the above period. These patients received ¹³¹I-MIBG therapy in the range of 1-8 cycles (75mCi- 1200 mCi) of MIBG therapy. Out of eighty patients, 30 patients had neuroblastoma, 12 patients had paraganglioma, 9 patients had MCT, 3 patients had ganglio-neuroblastoma, 21 had pheochromocytoma, 3 patients had carcinoidand 2 patients had carotid body tumor. The results of different types of tumor is given in Table 1.

Conclusion: All the patients who received 131-I-MIBG therapy were referred from different department and had progression in conventional CT/inoperable primary mass with no other therapeutic options. MIBG therapy is effective in around 61% of all these patients in maintaining the disease status as stable condition or providing partial or complete response. The best therapeutic outcome of MIBG was found in metastatic para-ganglioma i.e 75% had SD. In our study only 3 patients (4%) developed hypothyroidism and 1 patient developed severe bone marrow suppression in long term follow up. So it can be concluded that the ¹³¹I-MIBG can be effectively used in patients who have exhausted all the therapeutic options.

Table 1.

Outcomes of different types of malignancies

Various types of malignacies received mibg therapy	SD (%)	PR (%)	PD (%)	CR	LTF
Neuroblastoma (30)	(13) 4	6 (20)	8 (27)	0	12 (40)
Pheochromocytoma (21)	(67) 14	3 (14)	3 (14)	1 (5)	0
Paraganglioma (12)	(75) 9	0	2 (17)	0	1 (8)
MTC (9)	(33) 3	1 (11)	3 (33)	1 (11)	1 (11)
Ganglioneuroblastoma (3)	(33) 1	1 (33)	0	0	1 (33)
Carotid body tumor (2)	(100) 2	0	0	0	0
Carcinoid (3)	1 (33)	2 (67)	0	0	0
Total patients (80)	34 (42.5)	13 (16)	16 (20)	2 (2.5)	15 (19)

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*Number given within the parenthesis represents absolute number of patients. SD: Stable disease, PR: Partial response, PD: Progressive disease, CR: Complete response, LTF: Loss to follow up, MTC: Medullary Thyroid cancer

PERMALINK

Abstracts

Category: Cardiology: Cardio 1: Agreement of 68Ga-68 DOTANOC PET/CT with 18F-FDG PET/CT and cardiac resonance imaging in sarcoid patients with suspected cardiac involvement

Ritanshu Solanki

Ashwani Sood

Uma Debi

Manphool Singhal

Ajay Bahl

Sahajal Dhooria

Harmandeep Singh

Saurabh Mehrotra

Cardio 2: A prospective comparative study between 99mTc MIBI myocardial perfusion single photon emission computed tomography and dobutamine stress echocardiography to detect viable myocardium in patients with coronary artery disease

D K Jha

V Bohra

A Mahato

A Jain

A Tiwari

Cardio 3: A novel quantitative scoring to predict improvement in left ventricular ejection fraction post revascularization in patients with ischemic cardiomyopathy

Surekha Yadav

Arun Ravi John

A G Pandit

A K Dash

Cardio 4: Molecular evaluation of myocarditis using 68Ga DOTATATE and 18FDG in rest MPI normal but symptomatic, suspected acute myocarditis patients

Sutapa Rakshit

Basant L Malpani

Sunita Sonawane

Nawab Singh Baghel

A K Tyagi

Cardio 5: Can machine learning decode hibernating myocardium from rest myocardial perfusion images?

Khangembam Bangkim Chandra

Jasim Jaleel

Arup Roy

Priyanka Gupta

Chetan Patel

Cardio 6: Association between right ventricular ejection fraction calculated by first pass radionuclide ventriculography and surrogate markers of right ventricular function assessed by echocardiography in dilated cardiomyopathy patients – A comparative study

S Dasgupta

M Mudalsha

S Singh

T Lukose

H Bansal

S Krishna

R Kote

M Reddy

Cardio 7: Role of hybrid single photon emission computed tomography myocardial perfusion imaging/computed tomography coronary angiography in detecting coronary artery disease in patients with dilated left ventricle and reduced ejection fraction

Brinda Ravichandran

Madhusudhanan Ponnusamy

Category: Endocrinology: Endo 1: Comparative study of functional and structural imaging modalities including 68Ga DOTATATE PET/ CT, 18F FDG PET/ CT, 131I mIBG and CECT in patients of pheochromocytomas and paragangliomas

C Ashwini

Saba Samad Memon

Anurag R Lila

Tushar R Bandgar

Sandip Basu

Ramesh Asopa

Gaurav Malhotra

Endo 2: Profiling of “bilateral diffuse pattern” of lung metastasis in thyroid cancer on radioiodine scan

Ashwini Kalshetty

Endo 3: Development of thyroid uptake calculation software using deep learning algorithm

Abhishek Kumar

Sushama Awasare

K Biju

N S Baghel

A K Tyagi

Endo 4: Preparation of 68Ga-NODAGA-RGD dimer as a radiotracer for tumor imaging at RMC

Ashok R Chandak

P Verma

G Malhotra

M K Ray

Endo 5: Efficacy of radioiodine therapy plus low dose lenvatinib in advanced metastatic differentiated thyroid cancer: A randomised controlled trial

S Chandra Teja Reddy

S Swayamjeet

Madhavi Tripathi

Ranjit K Sahoo

Chandrasekhar Bal

Endo 6: Clinical outcome of patients with differentiated thyroid cancer and raised antithyroglobulin antibody levels: A retrospective study

Kanishk Markam

Manish Ora

Aftab Hasan Nazar

Sukanta Barai

Amitabh Arya

Prasanta Kumar Pradhan

Category: Cardiology: Cardio 1: Agreement of ⁶⁸Ga-68 DOTANOC PET/CT with ¹⁸F-FDG PET/CT and cardiac resonance imaging in sarcoid patients with suspected cardiac involvement

Cardio 2: A prospective comparative study between ^99mTc MIBI myocardial perfusion single photon emission computed tomography and dobutamine stress echocardiography to detect viable myocardium in patients with coronary artery disease

Cardio 4: Molecular evaluation of myocarditis using ⁶⁸Ga DOTATATE and ¹⁸FDG in rest MPI normal but symptomatic, suspected acute myocarditis patients

Category: Endocrinology: Endo 1: Comparative study of functional and structural imaging modalities including ⁶⁸Ga DOTATATE PET/ CT, ¹⁸F FDG PET/ CT, ¹³¹I mIBG and CECT in patients of pheochromocytomas and paragangliomas

Category: Hepatology: Hepato 1: Safety profile assessment of ¹⁸⁸Re-N-DEDC lipiodol trans-arterial radionuclide therapy for treatment of hepatocellular carcinoma

Hepato 3: Comparison of clinical response of ¹⁸⁸Re-N-DEDC lipiodol and ⁹⁰Y-SIRsphere for treatment of Inoperable hepatocellular carcinoma

Infection 4: Pitfalls in ^99mTc-ethambutol scintigraphy in imaging patients with tuberculosis – What we should know