Superior Diagnostic Yield of 18F-rhPSMA-7.3 Compared With 18F-DCFPyL PET/CT for the Detection of Recurrent Prostate Cancer

Prostate-specific membrane antigen (PSMA)-targeted PET imaging plays a well-established role in staging, detecting recurrence, and selecting patients for PSMA-targeted radiopharmaceutical therapy in prostate cancer. We present a case of PSMA-expressing recurrent prostate cancer in the pelvis, involving the urinary bladder wall and pelvic lymph nodes that was not completely visualized on 18F-DCFPyL PET/CT, but clearly delineated on 18F-rhPSMA-7.3 PET/CT. This discrepancy is attributed to the significantly lower urinary excretion and consequent low urinary bladder activity with 18F-rhPSMA, yielding high target-to-background ratios in the pelvis, and highlighting its potential diagnostic advantage in evaluating pelvic lesions near the urinary bladder.