Samarium-152 is a radioactive isotope of the element samarium, which is a rare earth metal. It has a mass number of 152 and is used in various applications, including nuclear medicine and research. Its half-life is approximately 66 hours, making it useful for certain medical treatments and diagnostic procedures. In nuclear medicine, samarium-152 is utilized for targeted radiotherapy, particularly in treating bone pain from cancer. It emits beta particles, which can help destroy cancerous cells while minimizing damage to surrounding healthy tissue. This makes it a valuable tool in the fight against cancer.