On the basis of its excellent in vitro (logD, plasma protein binding, PSMA-affinity, internalization) and in vivo (stability, clearance kinetics, tumor uptake in LNCaP and PC3-PIp tumor-bearing mice) profile, [<sup>99m</sup>Tc]Tc-PSMA-HSG was selected as the clinical lead compound. The gene discussed is FOLH1; the disease is neoplasm.