Fig. 5

Qualitative evaluation of the transaxial images of the NEMA phantom of TOF-OSEM (3 iterations, 16 subsets, post-filter 5.0 mm and PSF) and BSREM with β = 750 (including TOF and PSF). Contrast ratios of 8:1, 6:1, 4:1, and 2:1 are shown in rows and acquisition times (1.0, 2.5, and 20 min) in column. Background level is 5.3 kBq/ml in all cases