Radioactive Iodine Treatment Basics

Radioactive iodine, given in a liquid form or pill, is absorbed and concentrated by the thyroid gland which is the only organ in your body with cells that actually absorbs iodine. The treatment destroys thyroid tissue but does not harm other tissue in the body.

*While radiation exposure can cause thyroid cancer, treatment of hyperthyroidism with radioactive iodine does not increase your chances of getting thyroid cancer.

Why Radioactive Iodine

Radioactive iodine is used after surgical removal of the thyroid gland (thyroidectomy) because of thyroid cancer. Radioactive iodine therapy destroys any remaining thyroid tissue or cancer cells that were not removed during surgery. Radioactive iodine may also be used to treat hyperthyroidism in people who have noncancerous (benign) thyroid nodules that make too much thyroid hormone.

What to Expect After Treatment

• Within days, the radioactive iodine passes out of your body in your urine.

• To avoid exposing other people to radioactivity, it is important to do the following for the first one week after your radioactive iodine treatment:

• Drink plenty of fluids –an eight ounce glass of water every couple of hours is ideal  to help flush the radiation out of your body.

• Avoid children, pregnant women and pets for a minimum of one week.

• Remain a minimum of 3 feet away from people at all times for at least one week.

• Do not sit next to someone in a motor vehicle for more than 1 hour for one week.

• Avoid kissing or sexual intercourse for a minimum of one week.

• Do not sleep with your spouse or anyone else in your own room for one week (if you have small children it is best to stay in a hotel the first few days).

• Use separate (or disposable) eating utensils for the first one week after treatment, wash them or dispose of them separately.

• Use separate towels, washcloths, and sheets. Wash these items and all your personal clothing separately for one week. (Ideally keep get rid of them).

• Wash your hands with soap and lots of water frequently, specially each time you use the toilet and before touching any cooking utensils.

• Keep the toilet very clean: flush the toilet 2 or 3 times after each use. Men should urinate sitting down to avoid splashing for one week.

• Rinse the bathroom sink and tub thoroughly 2 or 3 times after using them for one week.

How Well It Works

In almost all cases, your thyroid hormone levels will return to normal or below normal after radioactive iodine treatment. This may take 8 to 12 weeks or longer. If your thyroid hormone level does not go down after 6 months, you may need another dose of radioactive iodine.

If you have thyroid cancer and you are treated with radioactive iodine, it may take from several weeks to many months for your body to get rid of any remaining cancer cells.

Your thyroid nodule is unlikely to grow after being treated with radioactive iodine.

Common Side Effects

• The risks from radioactive iodine treatment include:
• Metallic taste in your mouth.
• Dry mouth.
• Sore throat.
• Neck pain. Radioactive iodine treatment can make your neck swell up or hurt.
• Nausea or vomiting, which is usually mild.
• Constipation or diarrhea.
• Extreme fatigue.
• Unusually low (hypothyroidism) or unusually high (hyperthyroidism) thyroid levels.

Important Risk Factors To Think About

If you are pregnant, you should not receive radioactive iodine treatment. This kind of treatment can damage your fetus's thyroid gland or expose your fetus to radioactivity. For this reason it is very important to stay away from pregnant women after radioactive iodine treatment.

You should NOT breast-feed your baby after you have been treated with radioactive iodine. Ask your doctor when it will be safe to breast-feed.

Different people with thyroid cancer will receive different doses of radioactive iodine. If you are young and you do not have a great risk of your cancer coming back, you will probably need less radioactive iodine than an older person. Sometimes this means that a younger person who receives radioactive iodine treatment will not have to stay overnight in a hospital.

If you have had radioactive iodine treatment and you want to travel 3 to 4 days after treatment, it is important to prepare for any problems you may have at airport security. People who have had radioactive iodine treatment can set off the radiation detection machines in airports and other public/government buildings. If you plan to travel by airplane within 3 or 4 days after your treatment, check with local authorities about any steps or permission you may need to travel.

A special low iodine diet  must be followed prior to radioactive iodine treatment so that it can be effective. Sometimes antithyroid medication such as Thyrogen are used before radioactive iodine to treat a noncancerous nodule that is making too much thyroid hormone and causing hyperthyroidism.

MEDICAL REVIEW 02/28/2012