Fig. 7

Examples from enema group showing TAC at 45 min, 2 h and 4 h PET from tumour (a) and bladder (b). The TAC in a and b correspond to patient in Fig. 6. The TACs show the effect of bladder activity on the apparent tumour activity after removal of the non-tumour activity in the rectum before the 4 h time point. The changes in tumour activity were much smaller compared to those seen in bladder as apparent from the y-axis. Since the patient emptied their bladder between 2 and 4 h, the bladder activity showed an increase of only 6% and correspondingly an increase of 6.25% in tumour activity was observed. However, it is still unclear if this increase in tumour activity is due to the spill-out from bladder or accumulation of tracer in hypoxic cells, or both. Alternatively, it is possible that the [¹⁸F]FMISO in hypoxic cells reached an equilibrium state by 4 h post injection, and the increase in tumour activity could be purely an effect of increased bladder activity. TAC = time-activity curve; min = minute; h = hour; PET = positron emission tomography; % = percentage; [¹⁸F]FMISO = [¹⁸F]fluoromisonidazole; kBq = kilo Becquerel; ml = millilitre; 1 millilitre = 1 cm³