[177Lu]Lu-PSMA-137

This study is a prospective, single-center, single-arm clinical trial consisting of two parts. In Part A, 3 participants were enrolled to receive sequential administrations of low doses of [177Lu]Lu-PSMA-137 and [177Lu]Lu-PSMA-617. Pharmacokinetics（PK） sampling and single-photon emission computed tomography/computed tomography (SPECT/CT) scans were performed at scheduled time according to the protocol. Based on quantitative pharmacological results, the optimal dosing regimen for [177Lu]Lu-PSMA-137 was derived. In Part B, 3 participants were enrolled to receive treatments with 50% and 100% of the optimal dose of [177Lu]Lu-PSMA-137, to preliminarily evaluate the safety, tolerability, radiation dosimetry, and efficacy of [177Lu]Lu-PSMA-137 in participants with metastatic castration resistant prostate cancer (mCRPC).