Procedures [
Patients received an intravenous injection of [Total body PET-CTs were performed on a Biograph Vision 600 PET-CT scanner (Siemens Healthineers), at both 1 h and 2 h post-injection to assess the optimal timing for image acquisition. First, a low-dose CT scan was acquired with an automatic tube voltage selection and current modulation (reference: 100 kV, 20 mAs) using CARE kV and CARE Dose4D (Siemens Healthcare). Total body PET scanning was performed using continuous bed motion, scanning two passes at 1.6 mm/sec for head to pelvis and 3.2 mm/sec for lower limbs. Low-dose CT was used for attenuation correction of PET data. PET images were reconstructed using point spread function and time of flight modelling, four iterations with five subsets, and 4-mm Gaussian filtering. Image reconstruction matrix was 440 × 440 resulting in 1.65 × 1.65 mm pixels. PET images were reconstructed to a slice thickness of 3 mm.To obtain time-activity curves and to estimate radiation absorbed doses of [