The three sets of spheres made from the same 18FDG-solution were scanned using Siemens Biograph 64 Truepoint PET/CT. PET raw data from the late part of the dynamic scan, for a true sphere-to-background ratio around 13:1, were reconstructed using without and with PSF (same reconstructions as in Fig. 2). For each sphere size, RCs should be similar as seen for reconstruction without PSF. However, RCs were less reproducible and non-monotonic when using PSF reconstruction. For 10, 6, and 4 mm spheres, the symbols are mean values and error bars are ± standard deviation (N = 3). The 3-mm sphere in free air was missing.