Fig. 1

The schematic figure of transverse image slices of the NEMA IQ phantom achieved at the different acquisition time, iteration number, and injected activity. The PET raw-data were measured from the NEMA IQ phantom with a background activity of ~ 5.2 MBq/L (hot sphere-to-background ratio = 4:1) scanned for 30 min. By truncating the list-mode PET raw-data, a series of PET images were reconstructed into 40 s, 1 min, 2 min, 3 min, 5 min, 10 min and 30 min (ordered from left to right column), where the iteration number applied in OSEM-TOF-PSF reconstruction process was 2, 3, 4, 5, and 15 from top to bottom line, respectively. The activity per body weight was estimated from the instantaneous background activity concentration taking into account of the nature decay of ¹⁸F nuclide for a waiting time of 60 min after injection. The activity per body weight ranged from 0.24 to 7.61 MBq/L