Iodine-133 is a radioactive isotope of iodine, with a half-life of about 20.8 hours. It decays by emitting beta particles and gamma radiation, making it useful in various medical and industrial applications. In medicine, Iodine-133 is often used in diagnostic imaging and treatment of thyroid conditions. Its short half-life allows for quick decay, minimizing radiation exposure to patients. Additionally, it can be used in research to study biological processes and the behavior of iodine in the body.