What is I-131 Therapy?

I-131 therapy, or radioactive iodine therapy, is a treatment for patients who suffer from hyperthyroidism. This kind of therapy can also be used to treat thyroid cancer.

Why is it performed?

I-131 therapy can be used to treat and manage hyperthyroidism. The thyroid is a gland that produces important hormones, which work to regulate the body's metabolism. The process is essential for converting food into energy, but in cases where the thyroid is overactive, too many hormones are produced, and the metabolism works too quickly. I-131 Therapy is useful in managing and treating this condition.

How does it work?

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Therapy for hyperthyroidism is administered in the form of a capsule. It is not a large capsule (the size of an antibiotic capsule). Radioactive iodine (I-131), will be absorbed in the thyroid via the blood stream. The iodine will become concentrated in the thyroid gland, and work to break down cells in these glands. The dosage of radioactive iodine is very small. It is absorbed into the bloodstream relatively quickly and therapy works effectively. Normally only one capsule is necessary, but in some cases, depending on the severity of your hyperthyroidism, your doctor will advise more than one capsule. Medical treatment (Neo-Mercazole) prior to radioactive iodine treatment is normally prescribed by the practice for patients with hyperthyroidism.

There should be no cause for concern when it comes to side effects. Radioactive iodine therapy is in fact a very safe and effective treatment option. Even patients normally allergic to elemental iodine (in certain foods e.g. shell fish or iodinated contrast administered in some radiology scans) can be treated with radioactive iodine. The amount of radioactive material that enters the body is extremely low, so the risks are extremely low.