Radioactive Iodine for Thyroid Cancer

Treatment for Thyroid Cancer

Written by James Norman MD, FACS, FACE

Radioactive iodine therapy, often referred to as RAI, is used following surgery for certain types of thyroid cancer; specifically, follicular and papillary and may also be useful for some differentiated types.

Read about other treatments for thyroid cancer in our Patients' Guide to Thyroid Cancer.

A thyroidectomy is a type of thyroid surgery used to remove the thyroid when cancer is present. However, some thyroid cells may remain after the procedure To prevent thyroid cancer recurrence, RAI is done to kill any remaining, possibly cancerous, thyroid cells.

Should thyroid cancer spread to other parts of the body,  radioactive iodine is often recommended to distroy those cells, as well.

How Radioactive Iodine Therapy Works

Thyroid hormone-producing cells are the only cells in your body that absorb iodine. The cells collect and concentrate iodine from our diets (such as from iodized salt, which is common in processed foods, deli meats, fast food and dairy products, to name a few) and use the iodine to make thyroid hormones (T3 and T4—read more about thyroid hormones in our thyroid gland overview).

Since no other cells in the body can absorb iodine, doctors can give an individual radioactive iodine to destroy  thyroid cells, while not harming cells from other organs. The majority of radioactive iodine, therefore, will be absorbed by any remaining thyroid cells.

Very small amounts of radioactive iodine may be absorbed by your salivary glands, and the lining of your stomach, which may cause side effects such as a sore throat or hoarseness. If this occurs, it is usually goes away as the body heals.

A certain form of radioactive iodine is used: I-131. That is the form that has been found to be the most effective in eliminating remaining thyroid cells.

Radioactive Iodine Therapy Basics

Your doctor will walk you through step-by-step what will happen in your radioactive iodine therapy. Here are some basics to keep in mind, though:

Radioactive iodine therapy has been used since the 1950s. The risk is low, and the benefits are important for a good recovery. RAI is a very common and accepted treatment for thyroid cancer patients following thyroid surgery.