About radioactive iodine therapy
The radioactive form of iodine (I-131) is often used to treat hyperthyroidism and thyroid cancer, and in small doses, to test thyroid function. Iodine is a natural substance your thyroid uses to make thyroid hormone.
Radioactive iodine (RAI) is collected by your thyroid gland in the same way as non-radioactive iodine. Since the thyroid gland is the only area of the body that uses iodine, RAI does not travel to any other areas of the body (except for small amounts that go to the salivary glands), and the RAI that is not taken up by thyroid cells is eliminated from the body, primarily in urine.
RAI is therefore a safe and effective way to test and treat thyroid conditions. Extensive studies have shown that patients who have been treated with radioactive iodine are not at increased risk for thyroid cancer or any other type of cancer. Prior to administering the RAI, the goal is to prepare the body to take up as much of the iodine as possible.
This preparation is done by either stopping thyroid hormone pills for a 2 to 4 weeks prior or by administering a medication called Thyrogen (a man-made form of thyroid stimulating hormone) — the hormone that tells your thyroid to increase its activity levels.
Radioactive iodine, given in a capsule or liquid form, is absorbed and concentrated by the thyroid gland. Within days, the radioactive iodine passes out of your body in your urine and saliva. How long it takes will depend on the dose you received and your age. Young people get rid of radioactive iodine faster than older adults.
Most people don’t feel different after treatment. But a few people may feel a little nauseated.
It is important to note, that pregnant or breast feeding woman should never receive RAI for any reason because it may destroy the developing fetus’ thyroid — you should wait 6 to 12 months before attempting to get pregnant after treatment with RAI.