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Radioactive Iodine Treatment

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by Kohnle D

(Radioiodine Treatment)


Reasons for Procedure

It may be done to treat:

Possible Complications

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

Description of 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.

How Long Will It Take?

At least an hour

Will It Hurt?

The treatment is painless.

Postoperative Care

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:
  • Do not eat any solid foods for at least two hours after treatment. Drink a lot of clear liquids, such as water or juice.
  • For the first 8-12 hours following treatment, use the bathroom every hour. This will help flush the excess iodine from your body.
  • Limit your contact with others. Do not enter a room with any infants or children. Stay at least three feet away from other adults. Do not stay near any other adult for more than a few minutes. Do not share a bed with anyone for 48 hours following the treatment.
  • Do not share any food, drink, or dishes with anyone for the first week. Do not allow your saliva to come into contact with anyone. Avoid kissing and sexual contact.
  • Flush the toilet twice after use.
  • Wash hands often and thoroughly.
  • Resume normal thyroid medications 48 hours after the treatment.
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 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.


American Association of Clinical Endocrinologists

Endocrine Society



Health Canada

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.

Radioactive iodine for hyperthyroidism. The Endocrine Society Hormone Health Network website. Available at: Accessed November 25, 2013.

Radioiodine (I-131) therapy. Radiological Society of North America Radiology Info website. Available at: Updated March 27, 2013. Accessed November 25, 2013.

Rivkees SA, Dinauer C: An optimal treatment for pediatric Graves’ disease is radioiodine. J Clin Endocrinol Metab. 2007; 92:797-800.


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