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, where it treats disease by destroying the cells. However, the radioactivity is not spread to other parts of the body.

The Thyroid Gland

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Reasons for Procedure

It may be done to treat hyperthyroidism]]>, where the thyroid gland is overactive. The procedure is also used to treat certain types of ]]>cancers]]>, including ]]>thyroid cancer]]>.


Possible Complications

Possible side effects and complications of radioactive iodine therapy include:

  • Inflammation of the salivary glands causing painful cheeks and dry mouth
  • Metallic taste in the mouth
  • Dry mouth
  • Sore throat]]>
  • Pain in the neck
  • Nausea or vomiting
  • Fatigue
  • Flushing
  • Tightness in throat
  • Abnormally high or abnormally low thyroid hormone levels

Pregnant women are at an increased risk of complications. Since 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

Prior to Procedure

  • If advised by your doctor, eat a special diet. Your doctor may want you on a special low iodine diet prior to the procedure. This may help your procedure to be more successful.
  • Talk to your doctor about your medicines. Some thyroid hormone medicine should be discontinued four weeks before the procedure. Other medicines used to treat hyperthyroidism (eg, propothyouracil]]>, ]]>methimazole]]>) should be discontinued 5-7 days before the procedure.
  • For two hours before the procedure, do not eat or drink anything. Water may be allowed.
  • If you are a woman of childbearing age, the doctor will do a pregnancy test.
  • A ]]>thyroid uptake and scan]]> may be done before the treatment.

Description of the Procedure

You will be given some tablets 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, which may include:

  • Do not eat any solid foods for at least two hours following the treatment. Drink a lot of clear liquids (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 in it. 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 medicines 48 hours after the treatment.

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. Your doctor will need to check your thyroid status every few months until levels are stable.


Call Your Doctor

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 911.