Re-treatment 225Ac-J591 for mCRPC

In this study, subject enrollment will be done in a re-treatment design. A single dose of 225Ac-J591 given at the specified dose per cohort. The initial planned dose level will be determined based upon prior radioactivity exposure level. Those with moderate exposure (up to 30 GBq of 177Lu) will start with 65 KBq/Kg and those with heavy prior exposure (more than 30 Gbq of 177Lu or any 225Ac) will start with 50 KBq/Kg.