The study was aimed at assessing the diagnostic performance of 68Ga-PSMA-617 PET/CT in the detection of prostate cancer (PCa) in patients with a prostate-specific antigen (PSA) level of 4–20 ng/ml and to compare its efficacy with that of multiparametric MRI (mpMRI). The gene discussed is KLK3; the disease is prostate carcinoma.