Samarium-153-ethylene diamine tetramethylene phosphonate

Overview
Samarium-153-ethylene diamine tetramethylene phosphonate, Samarium-153 EDTMP, or simply Samarium-153 is a complex of a radioisotope of the lanthanide element Samarium with carrier EDTMP which is used to treat pain when cancer has spread to the bone. Samarium-153 is injected into a vein and distributes throughout the body. Samarium-153 EDTMP homes in on areas where cancer has invaded the bone. Once there, the radioisotope emits beta particles (electrons) which kill the nearby cancer cells. Pain begins to improve in the first week for most people and the effects can last several months. It is commonly used in lung cancer, prostate cancer, breast cancer, and osteosarcoma. Side effects result from radiation to the bone marrow and include thrombocytopenia and leukopenia.