Iodine is a mineral found in certain foods. Cells in your thyroid gland absorb iodine and use it to make thyroid hormone. The thyroid heavily relies on iodine for proper function.
Most thyroid cancer cells also absorb iodine. Penn Medicine experts use a special type of iodine called radioactive iodine (RAI) to image thyroid cancer and destroy these cancer cells.
The Penn Medicine Difference
Specialists in the Abramson Cancer Center lead the field in treating thyroid cancers. Expert physicians and physicists in our nuclear medicine program use sophisticated equipment to deliver precise radioactive iodine therapy.
The American Board of Nuclear Medicine has certified our experts in treating thyroid cancer with radioactive iodine. We continuously research new methods and techniques for using radioactive iodine therapy to treat thyroid cancer.
What is Radioactive Iodine (RAI) Therapy for Thyroid Cancer?
Radioactive iodine, or radioiodine, is a type of iodine that emits radiation. We use different isotopes (types of radioactive iodine named for their atomic weight) to diagnose and treat thyroid cancer. These isotopes include:
I-123
We use this isotope, which emits less radiation, during radioactive iodine scans to see if thyroid cancer has spread (metastasized). You take a capsule containing a small amount of I-123 (iodine 123). Special cameras then scan for cancer cells, which take up I-123 and become visible.
I-131
Experts use this isotope to deliver radiation directly to tissues during radioactive iodine therapy. We use I-131 (Iodine 131) after surgery for thyroid cancer to eliminate any remaining thyroid tissue and destroy remaining cancer cells. I-131 can also be used for thyroid cancer that recurs after initial treatment, especially for the rare instances where it has spread to other parts of the body.
Benefits of Radioiodine Therapy in Thyroid Cancer
After surgery, RAI destroys any thyroid cells that remain after surgery.
Radioactive iodine also helps treat thyroid cancer that has spread. Penn Medicine experts use dosimetry, a sophisticated process that delivers individualized high doses of radiation to maximize treatment effectiveness while preventing side effects.
What Are the Side Effects of Radioactive Iodine?
After RAI therapy, your body will emit radiation. You'll need to take precautions to make sure you don't expose people around you to this radiation. Your team will talk to you about how to prepare and what to expect. Depending on your I-131 dose, you may need to:
- Avoid public transportation and long car trips with others
- Pay careful attention to personal hygiene (especially your body fluids)
- Skip preparing food for others
- Sleep in a separate bed from your partner
- Social distance from other people
- Stay home from work
Most low-dose RAI treatments have few or no side effects. At higher doses, you might notice some side effects from your therapy, including:
- Changes in taste
- Dry mouth
- Nausea or vomiting
- Soreness or swelling in your salivary glands
- Swelling or soreness in your neck
How to Prepare for Radioactive Iodine Therapy
Your doctor will have you prepare for RAI therapy by eating a low-iodine diet for a week or so before your treatment. Your doctor may ask you to avoid:
- Bread
- Dairy products
- Eggs
- Iodized salt
- Leafy vegetables
- Prepared foods
- Seafood
If you take thyroid hormone pills, in most cases, you will continue to take them and will also have injections of synthetic thyroid-stimulating hormone.
Other Treatments for Thyroid Cancer
Not everyone with thyroid cancer needs radioactive iodine therapy. Depending on your risk factors and whether cancer has spread, your doctors might recommend no treatment beyond surgery or may recommend other types of thyroid cancer treatment.
Thyroid Cancer Support Services
We provide a range of services to support you and your family during and after thyroid cancer treatment. Learn more about our thyroid cancer support services.
Make an Appointment
Please call 800-789-7366 or request a callback.