I-131 Therapy

Radioactive iodine (I-131), an isotope of iodine that emits radiation and is used for medical purposes. When a small dose of I-131 is swallowed, it is absorbed into the bloodstream in the gastrointestinal tract and concentrated from the blood by the thyroid gland, where it begins destroying the gland's cells.

Radioactive Iodine I-131 (also called Radioiodine I-131) therapy is a treatment for an overactive thyroid, a condition called hyperthyroidism. Hyperthyroidism can be caused by Graves' disease, a condition where the entire thyroid gland is overactive, or by nodules within the gland which are locally overactive in producing too much thyroid hormone.

Radioactive iodine I-131 may also be used to treat thyroid cancer.