Comparison of [18F]DCFPyL and [68Ga]Ga-PSMA-HBED-CC for PSMA-PET Imaging in Patients with Relapsed Prostate Cancer

Purpose Gallium-68 (Ga-68)-labeled tracers for imaging expression of the prostate-specific membrane antigen (PSMA) such as the [ 68 Ga]Ga-PSMA-HBED-CC have already demonstrated high potential for the detection of recurrent prostate cancer. However, compared to Ga-68, a labeling with fluorine-18 (F-18) would offer advantages with respect to availability, production amount, and image resolution. [ 18 F]DCFPyL is a promising F-18-labeled candidate for PSMA-positron emission tomography (PET) imaging that has been recently introduced. In the current study, we aimed to compare [ 68 Ga]Ga-PSMA-HBED-CC and [ 18 F]DCFPyL for clinical use in biochemically relapsed prostate cancer. Procedures In 14 selected patients with PSA relapse of prostate cancer, [ 18 F]DCFPyL PET/X-ray computed tomography (CT) was performed in addition to [ 68 Ga]Ga-PSMA-HBED-CC PET/CT. A systematic comparison was carried out between results obtained with both tracers with regard to the number of detected PSMA-positive lesions, the standardized uptake value (SUV) max and the lesion to background ratios. Results All suspicious lesions identified by [ 68 Ga]Ga-PSMA-HBED-CC were also detected with [ 18 F]DCFPyL. In three patients, additional lesions were observed using [ 18 F]DCFPyL PET/CT. The mean SUV max in the concordant [ 18 F]DCFPyL PSMA-positive lesions was significantly higher as compared to [ 68 Ga]Ga-PSMA-HBED-CC (14.5 vs. 12.2, p = 0.028, n = 15). The mean tumor to background ratios ( n = 15) were significantly higher for [ 18 F]DCFPyL compared to [ 68 Ga]Ga-PSMA-HBED-CC using kidney, spleen, or parotid as reference organs ( p = 0.006, p = 0.002, p = 0.008), but no significant differences were found using the liver ( p = 0.167) or the mediastinum ( p = 0.363) as reference organs. Conclusion [ 18 F]DCFPyL PET/CT provided a high image quality and visualized small prostate lesions with excellent sensitivity. [ 18 F]DCFPyL represents a highly promising alternative to [ 68 Ga]Ga-PSMA-HBED-CC for PSMA-PET/CT imaging in relapsed prostate cancer.