Iodine-131 (I-131) is a radioactive substance produced in nuclear reactors that provides the medical isotope for nuclear medicine procedures. At high therapeutic doses, radioisotopes can be injected intravenously to effectively penetrate and destroy tumor tissue through localized radiation. Your healthcare provider will take steps to protect your thyroid from medication. Radioactive isotopes also release gamma particles, which can be captured by specialized gamma cameras during a molecular imaging process called scintigraphy. I-131 can be combined with molecular compounds to further personalize treatment and isolate radiotherapy to specific cells and their physiological functions.

I-131 radiation therapy is a treatment for hyperthyroidism and thyroid cancer. For thyroid cancer, I-131 radiation therapy is usually given after thyroid removal surgery to destroy any remaining cancerous or healthy thyroid tissue.

In I-131 radiation therapy, the radioactive substance used is radioactive iodine I-131. Patients swallow r