The lead candidate was then (i) evaluated for its radiochemical and biological properties after addition of a radionuclide chelator; (ii) used as a base monomeric unit for the construction of a homobivalent ligand; (iii) radiolabeled with the diagnostic radionuclide indium-111 and tested the monomeric and dimeric agents in a PSMA-positive LS174T tumor xenograft model by in vivo SPECT/CT imaging and ex vivo biodistribution. This evidence concerns the gene FOLH1 and neoplasm.