Radioactive Iodine Therapy | Endocrinology | Dartmouth-Hitchcock
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Radioactive Iodine Therapy

What is radioactive iodine therapy?
Why would a doctor recommend radioactive iodine therapy?
What does radioactive iodine therapy involve?
How long is the recovery after radioactive iodine therapy?

What is radioactive iodine therapy?

In radioactive iodine therapy, a patient swallows a small amount of a radioactive substance to destroy part or all of the thyroid gland, and make it unable to produce thyroid hormones. The treatment is safe, and has been used for over 50 years.

Why would a doctor recommend radioactive iodine therapy?

Radioactive iodine therapy is used as a treatment for hyperthyroidism, if anti-thyroid medication or surgery to remove part of the thyroid gland hasn't cured the condition. One dose of radioactive iodine treatment cures hyperthyroidism 80% or more of the time.

This therapy is also used to treat thyroid nodules that produce excessive amounts of thyroid hormone.

A doctor will sometimes recommend radioactive iodine therapy as a treatment for thyroid cancer, after a patient's thyroid gland has been removed by surgery. The treatment ensures that no thyroid tissue remains after surgery.

What does radioactive iodine therapy involve?

The thyroid gland uses iodine – found in foods such as fish, seaweed, and iodized salt – to produce its hormones. In radioactive iodine therapy, the patient swallows a pill or a liquid that contains radioactive iodine. The tissue of the thyroid gland naturally absorbs the iodine, and the radioactive substance destroys the thyroid tissue. After a few days, the radioactive substance will pass out of the body. In eight to 12 weeks, the overactive thyroid gland should produce normal levels of thyroid hormone.

In about 10% of cases, a patient will need a second dose of radioactive iodine. Very few people require surgery to remove the overactive thyroid gland after radioactive iodine therapy.

Doctors do not use radioactive iodine therapy with pregnant women. Women who are breast-feeding should stop before the treatment, to keep from passing the radioactive iodine on to their babies. A woman should avoid getting pregnant for six months after treatment.

How long is the recovery after radioactive iodine therapy?

You may feel nauseous after treatment. This usually goes away in a day or two. Your doctor will recommend that you drink lots of fluids, and go to the bathroom often.

Because your body will contain a small amount of radioactive substance for several days after treatment, you must keep a safe distance from other people, especially children and pregnant women. Sleeping in the same bed, or sitting beside another person for more than a few minutes, should be avoided for about two weeks after treatment. Do not share food and utensils with other people during this time. Flush the toilet twice after using it, to make sure no one comes in contact with radioactive bodily fluids.

In some cases, radioactive iodine treatment reduces the activity of the thyroid gland to a point where hypothyroidism, or underproduction of thyroid hormones, develops. Your doctor will monitor the level of thyroid hormones in your blood, and treat hypothyroidism if necessary.

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