Dual-time-point dynamic 68Ga-PSMA-11 PET/CT for parametric imaging generation in prostate cancer.

Abstract

To investigate the optimal dual-time-point (DTP) approaches using dynamic 68Ga-PSMA-11 PET/CT imaging to generate parametric images for prostate cancer patients. Fifteen patients with prostate cancer were intravenously administered 68Ga-PSMA-11 of 181.9 ± 47.2MBq, followed by an immediate 60min dynamic PET/CT scan. List-mode data were reconstructed into 25 timeframes (6 × 10s, 8 × 30s, and 11 × 300s) and corrected for motion and partial volume effect. DTP parametric images were generated using different interval time points of 5min and 10min, with a minimum of 30min time interval. Net influx rates (Ki) were calculated through the fitting of a single irreversible two-tissue compartmental model. Intraclass correlation coefficient (ICC) values between DTP protocols and 60min Ki were obtained. Lesion-to-background ratios (LBRs) of Ki and standardized uptake value (SUV) images in each DTP protocol were determined. The DTP protocol of 5-10min with a 40-45min interval showed the highest ICC of 0.988 compared with the 60min Ki, whereas the ICC values for the intervals of 0-5min with 55-60min and 0-10min with 50-60min were 0.941. The LBRs of the 60min Ki, 5-10min with 40-45min Ki, 0-5min with 55-60min Ki, 0-10min with 50-60min Ki, SUVmean, and SUVmax images were 29.53 ± 27.33, 13.05 ± 15.28, 45.15 ± 53.11, 45.52 ± 70.31, 19.77 ± 23.43, and 25.06 ± 30.07, respectively. The 0-5min with 55-60min DTP parametric imaging exhibits a comparable Ki to 60min parametric imaging and remarkable image quality and contrast than SUV imaging, enhancing prostate cancer diagnosis while maintaining time efficiency.