Radioactive medical waste tends to contain beta particle and gamma ray emitters. It can be divided into two main classes. In diagnostic nuclear medicine a number of short-lived gamma emitters such as technetium-99m are used. Many of these can be disposed of by leaving it to decay for a short time before disposal as normal waste. Other isotopes used in medicine, with half-lives in parentheses, include:
* Y-90, used for treating lymphoma (2.7 days)
* I-131, used for thyroid function tests and for treating thyroid cancer (8.0 days)
* Sr-89, used for treating bone cancer, intravenous injection (52 days)
* Ir-192, used for brachytherapy (74 days)
* Co-60, used for brachytherapy and external radiotherapy (5.3 years)
* Cs-137, used for brachytherapy and external radiotherapy (30 years)
* Tc-99, product of the decay of Technetium-99m (221,000 years)