What is I-131 Treatment? Who is the treatment for?
The thyroid gland is the only tissue in the body that uses iodine, which it uses to make thyroid hormones. I-131 is a radioactive isotope of iodine that detects and destroys iodine in the body, therefore killing thyroid cells. In my practice, I use this treatment for patients with high risk papillary or follicular thyroid carcinoma after complete surgical removal of the thyroid gland to detect and treat any remaining cancer cells that have spread to the neck, lymph nodes, or distant sites. Prior to treatment a low iodine diet is recommended. A detailed description of this diet can be found here on the American Thyroid Association website. In this treatment, a pill of I-131 is swallowed and absorbed into the bloodstream. Cells that take up iodine are then destroyed by the radioactivity of the I-131. A small dose of I-131 may be administered to detect the locations of thyroid cells. These detected thyroid cells give off radiation, allowing pictures to be taken giving the size and location of the cancerous cells. Some normal thyroid residual is expected in the central neck after surgery. If cancerous cells are detected, a larger dose of I-131 may then be administered to destroy the remaining thyroid cells.
What are the side effects?
Patients who undergo this treatment may have a sore throat shortly after the procedure. Hyperthyroidism symptoms such as nervousness, insomnia, and trouble concentrating may occur immediately after the procedure. Most patients will need to take inexpensive thyroid pills once a day for the rest of their lives due to hypothyroidism, or insufficient thyroid hormone levels, because the thyroid gland will be destroyed completely. A blood test may be administered several weeks after the procedure to determine the patient's hormone levels and therefore prescribe the right strength for the thyroid-replacement pills. There are no long-term side effects.
What are the safety requirements after the treatment?
Patients who undergo this treatment naturally give off small amounts of radiation that could potentially be harmful to others, especially pregnant women or small children. In order to protect others, follow the safety precautions below for each allotted amount of time.