The purpose of this study is to assess the efficacy, tolerability, safety, pharmacokinetic (PK) and dosimetry of 177Lu-PSMA-617, in participants with progressive prostate-specific membrane antigen (PSMA)-positive metastatic castration-resistant prostate cancer (mCRPC) in Japan. Furthermore, the safety, PK and dosimetry of 68Ga-PSMA-11 (PSMA imaging agent) are assessed in the same study. Another purpose of this study is to provide humanistic perspective access to study treatment (68Ga-PSMA-11 and 177Lu-PSMA-617) for the eligible patients with PSMA-positive mCRPC until marketed products are available in Japan. Furthermore, if data availability PK and dose rate of 177 Lu-PSMA-617 will be evaluated to refine discharge criteria in Japan. After obtaining manufacturing and marketing approval in Japan, this clinical trial will continue as a post marketing trial.