Definition

A diagnostic radioconjugate composed of a prostate-specific membrane antigen (PSMA)-targeting ligand that is linked, via the bifunctional, macrocyclic chelating agent 1,4,7,10-tetraazacyclododecane-1-(glutamic acid)-4,7,10-triacetic acid (DOTAGA; DOTA-GA), to the radioisotope technetium Tc 99m (Tc99m), that can potentially be used as a radioimaging agent for radio-guided surgery upon single-photon emission computed tomography (SPECT)/computed tomography (CT) for PSMA-overexpressing tumor cells. Upon administration, 99mTc-based PSMA-imaging and surgery (I&S agent targets and binds to PSMA on PSMA-expressing tumor cells. Upon SPECT/CT imaging, PSMA-expressing tumors can be visualized and identified. PSMA, a tumor-associated antigen (TAA), is overexpressed by most prostate cancers.