Radioactive Iodine Treatment
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. Though the radioactivity has minimal spread to other parts of the body, it will appear in the urine.
Reasons for Procedure TOP
It may be done to treat:
Possible Complications TOP
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.
What to Expect TOP
Prior to Procedure
Description of the Procedure
You will be given some tablets or liquids that contain radioactive iodine. After the iodine is swallowed, it will be taken up by the thyroid.
How Long Will It Take? TOP
At least an hour
Will It Hurt? TOP
The treatment is painless.
Postoperative Care TOP
Any radioactive iodine that is not taken up directly by the thyroid will be passed through the urine. Instructions may include:
The majority of people who undergo the treatment for hyperthyroidism will have their thyroid levels return to normal within 8-12 weeks. However, in a small number of people, a second dose of radioactive iodine treatment is needed.
A follow-up visit with your doctor may 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.
Call Your Doctor TOP
Call your doctor if any of these occur:
If you think you have an emergency, call for emergency medical services right away.
American Thyroid Association
Hormone Health Network—Endocrine Society
Thyroid Foundation of Canada
Pluijmen MJ, Eustatia-Rutten C, Goslings BM, et al. Effects of low-iodide diet on postsurgical radioiodide ablation therapy in patients with differentiated thyroid carcinoma. Clin Endocrinol (Oxf). 2003;58(4):428-435.
Radioactive iodine for hyperthyroidism. Endocrine Society Hormone Health Network website. Available at:
...(Click grey area to select URL)
Accessed December 14, 2015.
Radioiodine (I-131) therapy. Radiological Society of North America Radiology Info website. Available at:
...(Click grey area to select URL)
Updated February 12, 2014. Accessed December 14, 2015.
Rivkees SA, Dinauer C. An optimal treatment for pediatric Graves’ disease is radioiodine. J Clin Endocrinol Metab. 2007;92(3):797-800.
Last reviewed December 2015 by Kim A. Carmichael, MD
Last Updated: 12/14/2015
EBSCO Information Services is fully accredited by URAC. URAC is an independent, nonprofit health care accrediting organization dedicated to promoting health care quality through accreditation, certification and commendation.
This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.
To send comments or feedback to our Editorial Team regarding the content please email us at email@example.com. Our Health Library Support team will respond to your email request within 2 business days.