How does radioiodine work?

The thyroid gland accumulates iodine from the food you eat.  The thyroid gland uses this iodine to perform its normal function, which is to make thyroid hormone. Radioiodine is used to treat overactive thyroid glands and certain kinds of thyroid cancer.  It is mainly taken up by the thyroid gland. In the treatment of hyperactive thyroid glands, radiation from the radioactive I-131 damages a portion of the thyroid gland to reduce its activity.  Larger doses of I-131 may be used after thyroid cancer surgery to destroy any remaining diseased thyroid tissue.

How safe is radioiodine?

The practice of treating one’s thyroid with radioiodine or I-131 is a common, well accepted form of treatment.  Most of the radiation from the I-131 will be taken up by the thyroid gland. However, the other tissues in your body will receive some incidental radiation. This small amount of radiation does not produce any adverse effects. Radioiodine is never given to pregnant or nursing individuals.

How long does radioiodine stay in my body?

The radioiodine from your treatment will temporarily remain in your body. Most of the radioiodine not taken up by your thyroid gland will be eliminated within the first (2) two days after treatment. Radioiodine leaves your body primarily by your urine. Very small amounts may leave in your saliva, sweat, or feces.

Can others be exposed to radiation from the radioiodine given to me?

Exposure to radiation from the radionuclide in your body may occur if other people remain very close to you for extended periods of time. Try to keep the time you spend in close contact with others to a minimum. Contamination with radioiodine can occur if it is deposited in any place where other people may have contact with it. For instance, if some of the radioiodine in your saliva gets on the bathroom counter as you brush your teeth.  Contamination then occurs when someone’s hand comes in contact with the saliva. The person is then receiving a small amount of radiation exposure.

Three basic principles to keep in mind:

  1. Time: The amount of radiation exposure that another person may receive depends on how long you remain close to them.
  2. Distance: The greater the distance you are from others, the less radiation they will receive.
  3. Hygiene: Good hygiene will minimize the possibility that others will be contaminated with radioiodine that leaves your body. Most of the radioiodine leaves your body in the urine. So good toilet hygiene and careful. Thorough hand washing will reduce the possibility of contamination. Since radioiodine may also leave your body in your sweat, consider skipping the gym for a few days.

Instructions for Patients Taking Radioactive Therapy:

  1. The day you receiving the radioiodine, do not eat after midnight. No solid foods for two (2) hours after swallowing the radioiodine, you may drink fluids at any time.
  2. Drink plenty of fluids at least the first two (2) days.
  3. Empty your bladder frequently.
  4. Flush the toilet two (2) times after urinating for 48 hours.
  5. Maintain a prudent distance from others for at least the first two (2) days. If a small child(ran) are in the home, limit close contact, other than what is required for the child’s care.
  6. Sleep alone for at least the first night after being treated.
  7. Do not travel by airplane or mass transportation for at least the first day after treatment.