Definition

A radioconjugate composed of a human prostate specific membrane antigen (PSMA)-targeting agent conjugated, via the tris(hydroxypyridinone) (THP) chelator, to the radioisotope gallium Ga 68, with potential use as a tracer for PSMA-expressing tumors during positron emission tomography (PET). Upon intravenous administration of the gallium Ga 68-THP-PSMA, the PSMA moiety targets and binds to PSMA-expressing tumor cells. Upon PET imaging, PSMA-expressing tumor cells can be detected. PSMA, a tumor-associated antigen (TAA) and type II transmembrane protein, is expressed on the membrane of prostatic epithelial cells and overexpressed on prostate tumor cells.