PSMA binder-2 is a ligand for PSMA and can be used to synthesize Ac-PSMA-trillium. Ac-PSMA-trillium is a suitable PSMA-targeting compound with improved PSMA binding properties and pharmacokinetic properties. PSMA ligands have different biological applications after being modified with different radioactive isotopes. If labeled with ¹¹¹In, it can be used as DOTA chelating agent and imaging agent. Or labeled with ²²⁵Ac as a Macropa chelator for targeted radionuclide therapy (TRT) in the study of metastatic castration-resistant prostate cancer (mCRPC)^[1][2].