Which two radioactive materials are commonly used in medicine?

Iodine-131 and Technetium-99m are widely used in medicine primarily for diagnostic imaging and therapeutic purposes. Iodine-131 is particularly significant in the treatment of thyroid conditions, including hyperthyroidism and thyroid cancer, due to its capacity to emit beta particles and gamma radiation, which target thyroid tissue effectively. Its biological uptake by the thyroid gland allows for targeted treatment, exploiting the gland's natural function of absorbing iodine.

Technetium-99m is one of the most commonly used radioisotopes in nuclear medicine. It is favored for its ideal half-life of about six hours, which balances the need for sufficient time to perform various imaging procedures while minimizing radiation exposure to the patient. This isotope is utilized in a variety of diagnostic scans, such as bone scans, cardiac stress tests, and imaging of organs like the liver and kidneys, thanks to its ability to emit gamma rays that can be easily detected by imaging equipment.

The other choices consist of radioactive materials that are either not typically used in a medical context or are used for different purposes, such as research or radiation therapy for specific types of cancer but not as commonly as iodine-131 and technetium-99m for general medical applications.