CJE Open Check Practice Test

Radioactive iodine therapy uses a radioactive form of iodine that the thyroid gland readily takes up. Because the thyroid concentrates iodine to make hormones, the radioactive isotope (iodine-131) delivers targeted radiation to thyroid tissue, damaging overactive cells and lowering hormone production. This approach is often given as a capsule or liquid and can be used on an outpatient basis; it gradually reduces thyroid activity over weeks to months and may leave the patient with hypothyroidism, which is often managed with lifelong thyroid hormone replacement. It isn’t used in pregnancy or breastfeeding and involves brief radiation precautions after treatment. The other options don’t involve radioactivity: antithyroid drugs like propylthiouracil and methimazole inhibit hormone synthesis but don’t deliver radiation, and iodine solutions provide nonradioactive iodine and aren’t radioactive therapy.