Therapeutic applications of nuclear medicine are significantly expanding. The radioisotopes in therapy were limited predominantly to the treatment of hyperthyroidism, thyroid cancer, and polycythemia rubra vera and have been used for many years. Strontium-89 (Sr-89), rhenium-186 (Re-186), samarium-153 (Sm-153), tin-117 m (Sn-117), and recently radium-223 have been used in treating bone pain secondary to metastases. Additionally, treatment of certain neuroendocrine tumors with I-131 MIBG and labeled peptide receptor agents, treatment of prostatic cancer with Lu-177-labeled PSMA, the use of radiolabeled monoclonal antibodies for lymphomas, and radionuclide synovectomy have all revolutionized the field of therapeutic nuclear medicine. Recently, certain radionuclides have also been used for treating cases with breast cancer. Nuclear medicine treatment of tumors is expanding and is based on the targeted systemic approach, whether dealing with a primary tumor or with its metastatic foci.