Fig. 2
From: Image quality and detectability in Siemens Biograph PET/MRI and PET/CT systems—a phantom study
Spherical VOIs placed over the hot spheres in OSEM with PSF and TOF with activity concentration of 8:1 (3 iterations, 2 mm voxel size) (purple: d = 20 mm, cyan: d = 12 mm, green: d = 8 mm, pink: d = 6 mm, orange: d = 5 mm, red: d = 4 mm) and seven spherical background VOIs (yellow: d = 20 mm)