Radioactive Iodine, I-131, is a safe and effective, minimally invasive option to treat cats with hyperthyroidism.  Following one subcutaneous injection of I-131, over 98% of affected cats are cured of the disease. If needed, a second injection can be given. There are no harmful side effects.

How Does It Work?

Iodine is normally taken up by the thyroid gland. One form of iodine, I-131, is radioactive. When I-131 enters the thyroid gland it destroys the abnormally functioning cells. This reduces the size of the gland and its ability to produce thyroid hormone.