Fig. 4

Examples from non-enema group showing PET-CT scans at 45 min (a, d), 2 h (b, e) and 4 h (c, f) for 2 subjects in whom dynamic analysis was performed. The blue circular ROI of 10 mm radius was drawn on three consecutive slices in the bladder and red ROI encompassing the whole tumour. a–c show patient 1 (P1) tumour boundary in close proximity to the bladder. d–f show that patient 2 (P2) emptied the bladder before the 2 h scan as seen from the reduced volume/activity in the bladder in e compared with d and f. The bladder activity reaccumulated at 4 h (f) compared to 2 h (e). The accumulation of tracer within the rectum in images d–f is two transaxial slices distal to the tumour (not visible on these slices) and is ascribed to luminal excretion of the tracer. PET = positron emission tomography; CT = computed tomography; min = minute; h = hour; ROI = region of interest; mm = millimetre