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

The introduction of ¹⁸F-labeled prostate-specific membrane antigen (PSMA)–targeted PET/CT tracers, first ¹⁸F-DCFPyL (2-(3-{1-carboxy-5-[(6-¹⁸F-fluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid) and more recently ¹⁸F-PSMA-1007 (((3S,10S,14S)-1-(4-(((S)-4-carboxy-2-((S)-4-carboxy-2-(6-¹⁸F-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 ¹⁸F-DCFPyL versus ¹⁸F-PSMA-1007. Methods: Twelve prostate cancer patients, drug-naïve or before surgery, received similar activities of about 250 MBq of ¹⁸F-DCFPyL and ¹⁸F-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 SUV_max. Results: PSMA-positive lesions were detected in 12 of 12 prostate cancer patients. Both tracers, ¹⁸F-DCFPyL and ¹⁸F-PSMA-1007, detected the same lesions. No statistical significance could be observed when comparing the SUV_max of ¹⁸F-DCFPyL and ¹⁸F-PSMA-1007 for local tumor, lymph node metastases, and bone metastases. With regard to normal organs, ¹⁸F-DCFPyL had statistically significant higher uptake in kidneys, urinary bladder, and lacrimal gland. Vice versa, significantly higher uptake of ¹⁸F-PSMA-1007 in muscle, submandibular and sublingual gland, spleen, pancreas, liver, and gallbladder was observed. Conclusion: Excellent imaging quality was achieved with both ¹⁸F-DCFPyL and ¹⁸F-PSMA-1007, resulting in identical clinical findings for the evaluated routine situations. Nonurinary excretion of ¹⁸F-PSMA-1007 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 ¹⁸F-DCFPyL in late stages, when rare cases of liver metastases can occur.