Radioactive Iodine

Hyperthyroidism is a relatively common disease of older cats (usually over 10 years of age) that is caused by excess production of thyroid hormone from the thyroid glands. In most cases hyperthyroidism is caused by a benign tumor-like growth of the thyroid gland. In up to 4% of cats, however, the condition is caused by a malignant thyroid cancer, which can spread to other parts of the body.  Read more about Radioactive Iodine