Prostate-specific membrane antigen (PSMA) binding compounds having radioisotope substituents are described, as well as chemical precursors thereof. Compounds include pyridine containing compounds, compounds having phenylhydrazine structures, and acylated lysine compounds. The compounds allow ready incorporation of radionuclides for single photon emission computed tomography (SPECT) and positron emission tomography (PET) for imaging, for example, prostate cancer cells and angiogenesis.