Pronounced: RAY-dee-oh-AK-tiv I-oh-dine
by Diana Kohnle
Radioactive iodine treatment is used to treat certain thyroid diseases and thyroid cancer. The procedure is done with a radioactive form of the element iodine. Radioactive iodine is taken up by the thyroid gland. There it treats thyroid disease by destroying the cells. The radioactivity is not spread to other parts of the body.
It may be done to treat:
Possible side effects and complications of radioactive iodine therapy include:
Pregnant women are at an increased risk of complications. The procedure may be harmful to the fetus. It should not be done in pregnant women. Nursing mothers should stop breastfeeding for at least a week after the procedure.
You will be given some tablets or liquids that contain radioactive iodine. You will swallow the tablets. The iodine will be naturally taken up by the thyroid.
At least an hour
The treatment is painless.
Any radioactive iodine that is not taken up directly by the thyroid will be passed through the urine. Be sure to follow your doctor's instructions. This may include:
The majority of people who undergo the treatment will have their thyroid levels return to normal within 8-12 weeks. However, in a small number of patients, a second dose of radioactive iodine treatment is needed.
A follow-up visit with your doctor will be scheduled 4-6 weeks after treatment. Radioactive active iodine treatment can cause hypothyroidism (low thyroid function). This can occur at any time after treatment. It may be temporary or permanent. Your doctor will need to check your thyroid status every few months until levels are stable.
While side effects may occur, they are rarely severe. If the following persist for more than 24 hours, talk to your doctor:
In case of an emergency, call for medical help right away.
American Association of Clinical Endocrinologists
Thyroid Foundation of Canada
Effects of low-iodide diet on postsurgical radioiodide ablation therapy in patients with differentiated thyroid carcinoma. Clin Endocrinol (Oxf) . 2003;58(4):428-435.
Instructions for receiving radioactive iodine for hyperthyroidism. University of Washington Medical Center website. Available at: http://www.uwmedic... . Accessed December 31, 2012.
Radioactive iodine use for thyroid diseases. American Thyroid Association website. Available at: http://www.thyroid.org/patients/brochures/RadioactiveIRAI.pdf . Accessed December 31, 2012.
Radioiodine (I-131) therapy. RadiologyInfo website. Available at: http://www.radiologyinfo.org . Accessed December 31, 2012.
Rivkees SA, Dinauer C: An optimal treatment for pediatric Graves’ disease is radioiodine. J Clin Endocrinol Metab . 2007; 92:797-800
Last reviewed November 2012 by Kim Carmichael, MD
Last Updated: 11/26/2012