Clinical PET acquisition and image reconstruction.

Human participants underwent whole-body dynamic PET/CT after intravenous injection of 689.9 ± 15.4 MBq (range, 670.8–705.6 MBq) of ¹¹C-PABA, corresponding to a mean and SD administered mass of 0.5 ± 0.10 μg (range, 0.41–0.66 μg). A mid-thigh to the vertex of skull multibed dynamic PET was acquired using a Biograph mCT 128-slice PET/CT device (Siemens Healthineers) operating in 3-dimensional emission mode. PET data were acquired immediately after tracer injection using a multibed dynamic protocol for a total of 50 minutes after tracer injection. A helical CT (120 kVp, 30 mAs reference, 0.5 s/rotation, 0.8 pitch) was acquired and used for attenuation correction of the PET data and anatomic coregistration to delineate organ boundaries. Patients were asked to void the urinary bladder immediately after completion of the scan. The images were analyzed with Mirada XD (Mirada Medical) and PMOD (PMOD Technologies) for dynamic quantification. VOIs were drawn manually using the CT images as a reference for dosimetry calculation. Time-activity curves were generated and used to calculate organ TIACs for each participant. The resulting TIACs provided input data for the calculation of organ absorbed doses and effective dose for each participant using OLINDA/EXM.