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As a constituent of the thyroid hormones which regulate metabolism, iodine plays an important biological role in the body. Radioactive iodine is a form of iodine which is used to treat hyperthyroidism, a condition in which the thyroid gland becomes overactive. This type of iodine is also used in the treatment of thyroid cancer. In both cases, therapeutic iodine may be administered in pill form, or as a tasteless liquid.
Radioactive iodine therapy is an effective, safe, and simple treatment for both hyperthyroidism and thyroid cancer. The two main aspects of this treatment that make it so effective are its simplicity and safety. Just one dose is needed as a therapy for hyperthyroidism, making it an extremely efficient treatment. In terms of radiation therapy in general, radioactive iodine treatment is safe and has few side effects. This is because iodine is only used by the thyroid gland, and is not stored in other parts of the body.
Iodine forms the basis of an effective radiation treatment because the thyroid gland absorbs iodine from the bloodstream. Radioactive iodine is used in the same way as non-radioactive iodine by the thyroid. The only difference is that the radioactive type emits electrons. When radioactive therapeutic iodine is absorbed by the thyroid gland, the electrons it emits disrupt normal cellular function and reduce the amount of thyroid hormone which is produced. Therefore, the activity of an overactive thyroid gland is reduced to more normal levels.
Radioactive therapeutic iodine works in a similar fashion in the treatment of thyroid cancer. The iodine concentrates in the thyroid gland, where it kills off cancer cells. This treatment is usually a secondary therapy used after thyroidectomy surgery to remove the thyroid gland. After surgery is complete, therapeutic iodine is given to ensure any remaining cancer cells are killed.
Because treatment is highly targeted, even the most common side effects of radioactive iodine are relatively rare. One possible side effect is nausea, which may linger for several hours after treatment is administered, and can be reduced by avoiding food for two or three hours before and after treatment. The throat may be sore for a few days; this can be treated with over-the-counter pain medication. Much more rarely, the salivary glands may become swollen, due to the excess iodine present in the system.
Precautions should be taken following radioactive iodine to ensure that no susceptible individuals are exposed to radiation. First, contact with children and pregnant women should be minimized, and close contact avoided entirely. Utensils, dishes, and good should not be shared. Contact with the patient’s body fluids, including urine, sweat, saliva, and tears, must be prevented. In addition, women who are breast feeding must stop doing so. These precautions should be taken for up to two weeks, or as recommended by a physician.