Radioactive iodine for thyroid cancer

A woman of Hispanic descent is meeting with her doctor, a young Black man, about radioactive iodine treatment for thyroid cancer.


Radioactive iodine can help reduce the risk of thyroid cancer from coming back after surgery, and treat thyroid cancer that has spread


By Susana-Vargas-Pinto, MD, Endocrine Surgery, Nuvance Health


Yes, you will be radioactive after you ingest radioactive iodine to treat thyroid cancer. While that’s the most common question patients ask, here are answers to other questions about this treatment for thyroid cancer.


Thyroid cancer happens when cells grow out of control in the small, butterfly-shaped gland in the lower front of your neck.


Most people will only need surgery to treat early-stage thyroid cancer that has not spread. An endocrine surgeon or head and neck surgeon who specializes in thyroid surgery treats thyroid cancer. The type of thyroid surgery you need depends on the kind of cancer you have.


The endocrine surgeon should be part of a team of specialists who will consult on your care plan. These specialists usually include an endocrinologist, medical oncologist and radiation oncologist.


Your care team may recommend radioactive iodine (RAI), also called I-131, after a thyroidectomy to lower the risk of the cancer coming back. They may also recommend RAI to treat thyroid cancer that has spread.


Learn more about thyroid cancer, nodules and other endocrine diseases at Nuvance Health.


How does radioactive iodine for thyroid cancer work?

The thyroid gland produces hormones that regulate the body’s metabolism. The thyroid needs iodine to produce these hormones, which is why the gland absorbs the iodine in your body.


RAI is mainly absorbed by thyroid cells. RAI can eliminate any remaining thyroid tissue and thyroid cancer cells after surgery.


Related content: Diagnosed with thyroid cancer? Here’s what to expect.


When is radioactive iodine used to treat thyroid cancer?

People with papillary or follicular thyroid cancer that has spread to the neck or other parts of the body will usually have RAI after surgery. These are types of differentiated thyroid cancer.


RAI is not used to treat anaplastic or medullary thyroid cancer because these types of cancer do not take up iodine. These are types of undifferentiated thyroid cancer.


How is radioactive iodine for thyroid cancer administered?

Depending on the facility, an endocrinologist, nuclear medicine physician or radiation oncologist can administer the oral treatment. Most people will have one or two doses of RAI after thyroid cancer surgery.


Radioactive iodine is offered at the following Nuvance Health locations:


RAI treatment is a three-day, outpatient process for most people.


Day 1 includes blood tests and a thyrotropin alfa shot. Thyrotropin alfa helps any leftover thyroid tissue absorb the RAI.


On Day 2, you will get a second dose of thyrotropin alfa and a small dose of RAI. Then, you will have a full body scan so your doctor can see how your body will absorb the iodine.


On Day 3, you will receive the full dose of RAI, followed by a full body scan several days later.


How can you prepare for radiative iodine treatment?

Your care team will help prepare you for RAI treatment. At Nuvance Health, the team includes registered dietitians who are certified oncology nutritionists. You will need to follow a low-iodine diet for about a week before your treatment.


You may need to avoid foods high in iodine, such as iodized salt, some breads, cereals and grains, fish including shellfish, beef, poultry and dairy products.


What can you expect after radiative iodine treatment?


Your care team will provide detailed instructions about what to do after RAI treatment. Here some of the important things to know:

  • Plan to stay at the healthcare facility for an hour or two after the RAI treatment. You will not be able to have visitors, but you can use devices like your mobile phone. A member of your care team will monitor your radiation level with a hand-held device.
  • You will need to avoid others after treatment. Plan to drive yourself if you can. If you cannot drive yourself, stay as far away as possible from the other person in your car. Do not use public transportation after RAI treatment for 24 hours after treatment.
  • Drink a lot of water for about three days after RAI treatment to help the RAI leave your body.
  • Continue following a low-iodine diet for at least 24 hours after the RAI treatment.
  • You may emit small amounts of radiation for a few months after RAI treatment. Your care team will provide instructions about when you can resume normal activities.


The bottom line: Radioactive iodine may be part of your treatment plan if you have thyroid cancer. The treatment is used to reduce the risk of thyroid cancer recurring after surgery, or to treat cancer that has spread.


Learn more about cancer services at the Nuvance Health Cancer Institute.