Fig. 5.

Example of segmentation of selected regions for biomarker derivation requiring specification in standard operating protocols: Axial [¹⁸F]FDG PET/CT images through the mid thorax in a patient with a T3N1M0 non-small cell lung cancer. On the CT component in (A), contrast within the mass is poor. The PET scan (B, C) differentiates the tumour with a centrally necrotic area. The entire tumour has been segmented in (B), but as inclusion of necrosis impacts quantitative biomarker derivation, exclusion of the central necrosis during segmentation, as shown in (C), is preferable. The vital tumour volume was delineated using a threshold of 41% of the SUV_peak obtained using a sphere of 12 mm diameter, corrected for local background. The gross tumour volume was generated by adding the volumes of the central necrosis to the vital tumour volume