Comparison of imaging protocols for 18F-FDG PET/CT in overweight patients: Optimizing scan duration versus administered dose

The quality of 18F-FDG PET/CT images of overweight patients is often degraded. We evaluated the effect of optimizing injected dose or acquisition time on the quality of images of overweight patients using lutetium oxyorthosilicate PET/CT with high-performance detector electronics. Methods: We ini-tially retrospectively measured radioactivity concentrations and signal-to-noise ratios (SNRs) in the liver relative to body weight for 80 patients who had undergone 18F-FDG PET/CT according to our standard protocol (injected dose, 3.7 MBq/kg; acquisition time, 2 min/bed position). The patients were grouped (n5 20 per group) according to baseline body weight as G1 (#59 kg), G2 (60–69 kg), G3 (70–84 kg), and G4 ($85 kg). We compared the SNRs of G1 with those of G2, G3, and G4 and calculated the ratio squared as a factor to correct the acquisition parameters for overweight patients. We then prospectively enrolled 120 patient