Researchers at Albert-Ludwigs-Universität Freiburg and Deutsches Krebsforschungszentrum (DKFZ) have disclosed drug conjugates comprising fluorescent-labeled dye covalently linked to a radionuclide and a ligand targeting glutamate carboxypeptidase II (NAALADase; NAAG peptidase, FOLH1; PSMA) acting as positron-emission tomography (PET) and fluorescent imaging agents for diagnosis and treatment of prostate cancer.