What is the name of the radioactive compound given that concentrates in the thyroid gland?

The radioactive compound that concentrates in the thyroid gland is called iodine-131 (I-131). It is commonly used in medical treatments, particularly for hyperthyroidism and certain types of thyroid cancer, due to its ability to target and destroy thyroid tissue. The thyroid gland absorbs iodine, and the radioactive form effectively localizes in that organ, allowing for targeted therapy.