Definition

Radioactive iodine treatment uses a radioactive form of the element iodine to treat and/or diagnose hyperthyroidism (abnormally high thyroid levels) and certain types of cancers , including thyroid cancer .

Radioactive iodine is absorbed by the thyroid gland, where it treats disease. However, the radioactivity is not spread to other parts of the body.

The Thyroid Gland

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Parts of the Body Involved

To prevent exposing other areas of the body to the radioactive iodine, the treatment is limited to the thyroid only.

Reasons for Procedure

Radioactive iodine treatment is prescribed to treat hyperthyroidism in patients who have noncancerous nodules in the thyroid that produce excess hormones. The treatment is also used for certain types of cancers , including thyroid cancer .

Risk Factors for Complications During the Procedure

Pregnant women are at an increased risk of experiencing complications associated with the treatment. Radioactive iodine may be harmful to the fetus.

What to Expect

Prior to Procedure

Thyroid hormone medication should be discontinued four weeks prior to treatment.

Other thyroid medications used in the treatment of hyperthyroidism, specifically propothyouracil (PTU) or methimazole , should be discontinued four days before the treatment.

For two hours before the procedure, fasting (water only) is required.

Women of childbearing age will be asked to have a pregnancy test prior to the treatment to eliminate the possibility of pregnancy. Radioactive iodine therapy can be dangerous to a fetus.

A thyroid uptake and scan is performed prior to any radioactive iodine treatment so that the appropriate dosage of radioactive iodine to be administered is determined.

Anesthesia

None

Description of the Procedure

Patients swallow tablets containing radioactive iodine, which is then absorbed by the thyroid.

After Procedure

Any radioactive iodine that is not absorbed directly by the thyroid is excreted from the body via urine.

Don't eat any solid foods for at least two hours following the treatment. Do drink a lot of clear liquids (water or juice).

How Long Will It Take?

The treatment session will take at least an hour.

Will It Hurt?

The treatment is painless.

Possible Complications

Possible side effects and complications of radioactive iodine therapy include:

  • Metallic taste in the mouth
  • Dry mouth
  • Sore throat
  • Pain in the neck
  • Nausea or vomiting
  • Fatigue
  • Constipation or diarrhea
  • Abnormally high or abnormally low thyroid levels
  • Flushing
  • Tightness in throat

Average Hospital Stay

Radioactive iodine treatment is an outpatient procedure.

Postoperative Care

Guidelines include:

  • For the first 8-12 hours following treatment, use the bathroom every hour to help flush the excess iodine from the body.
  • Limit your contact with others. Do not enter a room with any infants or children, and stay at least three feet away from other adults. Don't stay near any other adult for more than a few minutes. Do not share a bed with anyone for 48 hours following the treatment.
  • Resume normal thyroid medications 48 hours after 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 thoroughly and frequently.

A follow-up visit with your doctor is required about four to six weeks after treatment.

Outcome

Prognosis following radioactive iodine treatment is usually favorable. The majority of patients who undergo the treatment will experience a return to normal thyroid levels within 8-12 weeks following treatment. However, in a small number of patients, a second dose of radioactive iodine treatment is needed.

Radioactive active iodine treatment can cause hypothyroidism , which can occur anytime after treatment. Therefore, your physician needs to check your thyroid status annually.

Call Your Doctor If Any of the Following Occurs

While the side effects mentioned above may occur, they are rarely severe. If they persist for more than 24 hours, consult your physician.