Intraindividual Comparison of 18 F-PSMA-1007 and 18 F-DCFPyL PET/CT in the Prospective Evaluation of Patients with Newly Diagnosed Prostate Carcinoma: A Pilot Study.

The introduction of F-18-labeled prostate-specific membrane antigen (PSMA)-targeted PET/CT tracers, first F-18-DCFPyL (2-(3-{1-carboxy-5[(6-F-18-fluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid) andmore recently F-18-PSMA-1007 (((3S, 10S, 14S)-1-(4-(((S)-4-carboxy2-((S)-4-carboxy-2-(6-F-18-fluoronicotinamido) butanamido) butanamido) methyl) phenyl)-3-(naphthalen-2-ylmethyl)-1,4,12-trioxo-2,5,11,13-tetraazahexadecane- 10,14,16-tricarboxylic acid)), have demonstrated promising results for the diagnostic workup of prostate cancer. This clinical study presents an intraindividual comparison to evaluate tracer-specific characteristics of F-18-DCFPyL versus F-18-PSMA-1007. Methods: Twelve prostate cancer patients, drug-naive or before surgery, received similar activities of about 250 MBq of F-18-DCFPyL and F-18-PSMA-1007 48 h apart and were imaged 2 h after injection on the same PET/CT scanner using the same reconstruction algorithm. Normal- organ biodistribution and tumor uptake were quantified using SUVmax. Results: PSMA-positive lesions were detected in 12 of 12 prostate cancer patients. Both tracers, F-18-DCFPyL and F-18-PSMA-1007, detected the same lesions. No statistical significance could be observed when comparing the SUVmax of F-18-DCFPyL and F-18-PSMA-1007 for local tumor, lymph node metastases, and bone metastases. With regard to normal organs, F-18-DCFPyL had statistically significant higher uptake in kidneys, urinary bladder, and lacrimal gland. Vice versa, significantly higher uptake of F-18-PSMA-1007 in muscle, submandibular and sublingual gland, spleen, pancreas, liver, and gallbladder was observed. Conclusion: Excellent imaging quality was achieved with both F-18-DCFPyL and F-18-PSMA-1007, resulting in identical clinical findings for the evaluated routine situations. Nonurinary excretion of F-18-PSMA1007 might present some advantage with regard to delineation of local recurrence or pelvic lymph node metastasis in selected patients; the lower hepatic background might favor F-18-DCFPyL in late stages, when rare cases of liver metastases can occur.