Fig. 2

Comparison of the frequency distribution of the deviations between the simulated TIACs and the ground truths using a the method with one SPECT/CT at 52 h and the hybrid planar/SPECT method with optimal sampling schedules comprising b two time points (TPs), c three TPs and d four TPs (Table 1). The kidneys (dark grey) and the tumours (white) of all 13 patients were considered. The systematic error of the simulated activity values based on planar images was assumed to contribute 50% to the total error