Intratumoral Heterogeneity on [18F]PSMA and [18F]FDG PET/CT in Predicting Invasion and Prognosis of Prostate Cancer

The purpose of this study is to analyze heterogeneity of prostate cancer（PCa）based on the head-to-head imaging of prostate-specific membrane antigen (PSMA) and fluorodeoxyglucose (FDG) positron emission tomography computed tomography (PET/CT)

PET/CT examinations were performed on different days using Siemens Biograph MCT PET/CT equipment. All patients were examined on the same scanner. Patients were fasted for more than 6 h before \[18F\]FDG PET/CT examination, blood glucose was controlled below 11.1 mmol/L, \[18F\]FDG injection dose was 3.7 MBq/kg, and \[18F\]FDG PET/CT examination was performed after 60 min rest. \[18F\]PSMA-1007 injection dose was 3.7 MBq/kg, and PET/CT scan was performed 60 min after injection. To avoid interference of prostate lesion detection by active urine in the bladder, patients were asked to urinate or undergo forced diuresis before the start of the examination. The scan was performed from the top of the head to the base of the thighs. Low-dose CT was taken with automatic milliampere-second 120 kV voltage scans with a matrix of 512 × 512 and a thickness of 5 mm, and PET/CT image acquisition was taken from 5-6 beds for 2-3 min each. CT data was used for attenuation correction at the end of the acquisition, reconstructed by the two-iteration method (21 subsets in total), and the True X +TOF algorithm was applied to reconstruct the images. Two nuclear medicine physicians with extensive experience in PET/CT interpretation evaluated the images using the LIFEx software v 7.1.0. Both readers were blinded to both clinical and pathological data