Comparison of [68Ga]Ga-PSMA-11, [18F]PSMA1007 and [177Lu]Lu-PSMA-617 in detecting the same prostate cancer lesions. The evidences from the clinical practice in a dedicated Cancer Institution.

Background. PET/CT with radiolabeled PSMA inhibitors gained clinical relevance in the imaging and therapy of mCRPC patients. Different PSMA radioligands are currently available for PET imaging but few data exist on comparative rate of detection, degree of uptake, correlation with RLT effectiveness, levels of PSA and disease symptoms. Methods. Fifteen mCRPC patients underwent to [68Ga]Ga-PSMA-11/[18F]PSMA-1007 PET/CT imaging, and to 4 up to 6 [177Lu]Lu-PSMA-617 RLT cycles (n. 6). The detection rate and the uptake in target lesions or in normal organs were compared to highlight similarities and differences. Results. [68Ga]/[18F]-PSMA-radioligands show similar rates of detection with overlapping levels of uptake in PCa sites, that is different in normal organs. In the six patients who completed RLT, [177Lu]Lu-PSMA-617 targeted the same lesions causing a drastic reduction in SUVmax after the second dose. Conclusions. These three PSMA radioligands concentrated in the same foci of PCa disease. Thus, the choice for PET imaging may be defined adopting the following parameters: local availability, costs of production/purchasing, number of studies and clinical demands for PET/CT per session. The use of PET radioligands did not influence a proper selection of patients to treat by RLT