Parametric analysis of the variations in FDG uptake before and during treatment. Left panel: before treatment (TEP1), right panel: at day 21 during treatment (TEP2), middle panel: co-registration of TEP1 and TEP2. The green voxels are those in which FDG uptake has decreased between TEP1 and TEP2; the red voxels are those in which FDG uptake has increased. Voxels in which FDG uptake remained stable do not appear. (A) All voxels are green, indicating homogeneous decrease in FDG uptake (patient was in CR at 1, but small Vg of 6 cm3). (B) An example of spatially heterogeneous response, with green and red voxels appearing in the same tumour (patient with recurrence at 1 year). (C) A 3D visualisation of the PI imaging.