California Thyroid Center

The hormones produced by the thyroid, a butterfly-shaped gland on the front of the neck, are essential for controlling how the body functions. However, the gland needs iodine to produce them. Thankfully, the thyroid is the only organ that can concentrate and store iodine. Radioactive iodine (RAI) therapy is based on this. Because radioactive iodine (I-131) may be absorbed and used by the thyroid in the same way as normal iodine, it is used in RAI therapy. However, once it gets there, it emits radiation that permanently destroys the thyroid tissue while sparing the rest of the body's tissues.