text: Radioactive isotopes are used in medicine for both treatment and diagnostic scans. The most common isotope used in diagnostic scans is Tc-99m (Technetium-99m), being used in approximately 85% of all nuclear medicine diagnostic scans worldwide. It is used for diagnoses involving a large range of body parts and diseases such as cancers and neurological problems. Another well-known radioactive isotope used in medicine is I-131 (Iodine-131), which is used as a radioactive label for some radiopharmaceutical therapies or the treatment of some types of thyroid cancer.