Fig. 3

Physical phantom. The NEMA small animal image quality phantom (a) contains five rods (B) (diameter 1–5 mm) was used to measure the recovery coefficients, homogeneous region to measure the uniformity (A middle), and 2-chamber region (C) (water- and air-filled) to measure the spill-over ratio. The mini-Derenzo phantom (b) was used to measure the effects of different filters on the spatial resolution of PET images