Application of Cu-64 NODAGA-PSMA PET in Prostate Cancer.

Introduction: The high diagnostic potential of Cu-PSMA PET-CT imaging was clinically investigated in prostate cancer patients with recurrent disease and in the primary staging of selected patients with advanced local disease. The aim of our study is to assess the uptake behavior in the clinical setting of 64Copper Prostate-Specific Membrane Antigen (Cu PSMA) Positron Emission Tomography/Computed Tomography (PET/CT) in prostate cancer.

Methods: A retrospective study was performed in 23 patients with intermediate, high risk and progressive disease at primary staging of prostate cancer. All patients underwent Cu-PSMA PET. Overall, 250 MBq (4 MBq per kg bodyweight, range 230-290 MBq) of Cu-NODAGA PSMA was intravenously applied. PET images were performed 30 min (pelvis and abdomen) and 1-2 h post-injection (skull base to mid-thigh). Maximum standardized uptake values (SUVmax) were measured in the organs with high physiological uptake such as liver and kidney, and, additionally, background activity was measured in the gluteal area and in suspected tumor lesions using a HERMES workstation.

Results: PSMA uptake was detected in prostate bed in nine patients, in six patients in distant metastases (bone, lung and liver) and in nine patients in lymph nodes. Of 23 patients, 5 (20.8%) did not show any focal pathological uptake in the whole body. The number of sites (prostate bed, lymph nodes, distant metastases) with positive PSMA uptake was significantly associated with PSA values before imaging (P = 0.0032). The Cu PSMA uptake increased significantly from 30 min to 1-3 h post-injection (Wilcoxon signed rank test, P = 0.002).

Conclusions: Cu NODAGA-PSMA PET is a promising imaging tool in the detection of residual disease in patients with recurrent or primary progressive prostate cancer. Furthermore, the increased tracer uptake over time indicates in vivo stability of the diagnostic radiopharmaceutical.