Prospective intraindividual comparison of F-18-PSMA-7Q and F-18-DCFPyL PET/CT in patients with newly diagnosed prostate cancer

Objective Fluorine 18 (F-18)-2-(3-{1-Carboxy-5-[(6-[(18)F]fluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid (DCFPyL) is an early F-18-labeled prostate-specific membrane antigen (PSMA) targeted PET tracer that has shown promise in the diagnostic workup of prostate cancer and was recently approved by the US Food and Drug Administration. F-18-PSMA-7Q is a novel F-18-labeled PSMA-ligand PET tracer designed and synthesized by our team. This study compared the tracer-specific positron emission tomography/computed tomography (PET/CT) characteristics of F-18-PSMA-7Q with those of F-18-DCFPyL in patients with newly diagnosed prostate cancer. Methods Ten patients received similar doses of F-18-DCFPyL and F-18-PSMA-7Q 48 h apart and were imaged 1 h after injection on the same PET/CT scanner. Normal-organ biodistribution and tumor uptake were quantified using maximum and mean standardized uptake values (SUVmax and SUVmean), and all lesions were assigned a molecular imaging PSMA (miPSMA) score based on Prostate Cancer Molecular Imaging Standardized Evaluation criteria. Results Seventeen lesions were detected in the 10 patients by both F-18-DCFPyL and F-18-PSMA-7Q. No statistically significant difference was observed when comparing the SUVmax and SUVmean of F-18-DCFPyL and F-18-PSMA-7Q in the lesions and parotid gland. The kappa value for the miPSMA scores of the lesions between the two tracers was 0.907, indicating excellent agreement. Conclusion F-18-PSMA-7Q can be used in clinical research as reliably as F-18-DCFPyL. The limited urinary excretion of F-18-PSMA-7Q may represent a potential advantage over F-18-DCFPyL for detection of lesions in the pelvis, which need to be verified by further studies.