Table 1.
Advantages and drawbacks of main radiotracers used in gliomas investigation in functional nuclear imaging.
| Physiopathology | Advantages | Drawbacks | |
|---|---|---|---|
| 18F-FDG | Carbohydrate metabolism | - Availability - Help in guiding biopsy - Prognostic role - Predictive role |
- Physiological brain fixation (false negative) - Lack of specificity (false positive) - No differentiation between low- and high-grade lesion - Disappointing in recurrence from radiation necrosis differentiating - Disappointing in radiotherapy planning |
| 11C-choline and 18F-Fcholine | Cell membrane metabolism | - Grading gliomas - - Recurrence from radiation necrosis differentiation |
- Rare false positive and false negative - No differentiation between low-grade gliomas and non-neoplastic lesions |
| 11C-methionine | Amino acid transport | - Grading gliomas - Help in guiding stereotactic biopsy - Radiotherapy planning - - Predictive role |
- Limited use to on-site cyclotron - Controversial and results in differentiation between radiation necrosis and tumor recurrence |
| 18F-FDOPA | Amino acid transport | - Logistical advantage thanks to its 18F radiolabel - Early acquisition - Grading gliomas - Guiding biopsy - Radiotherapy planning - Recurrence from radiation necrosis differentiation - Prognostic role - Predictive role |
- Disappointing in radiotherapy planning - Availability compared to radiolabeled -PSMA |
| 18F-FET | Amino acid transport | - Logistical advantage thanks to its 18F radiolabel - No striatum uptake - Dynamic acquisition - Grading gliomas - Guiding biopsy - Radiotherapy planning - Recurrence from radiation necrosis differentiation - Prognostic role - - Predictive role |
- Availability |
| 18F-FLT | DNA synthesis | - Grading gliomas - Prognostic role - Predictive role |
- No distinction between non-tumor lesions and low-grade tumors - Compared to 18F-FDG no superiority in discriminating radiation necrosis from tumor recurrence |
| 18F-FMISO and 18F-FAZA | Hypoxia imaging | - Discriminating glioblastomas from other gliomas - Prognostic role - Radiotherapy planning: boost on small hypoxic tumor areas |
−18F-FMISO: requires realization of early and delayed acquisition due to a high background activity |
| 68Ga-PSMA and 18F-PSMA | Endothelium of tumor-associated neovasculature imaging | - Differenciation between radiation necrosis and recurrence - Identification of residual disease immediately after surgery - Possible role in characterizing high and low-grade glioma - Role in peptide therapy to be investigated |
- Cerebral necrosis as a possible pitfall and possible false positive |