Thyroid radiation treatment, also known as radioactive iodine treatment, is a procedure in which radiation is used to destroy cells in the thyroid gland. The thyroid gland is located in the neck, where it uses iodine to make thyroid hormones which regulate the body's metabolism. Sometimes it becomes overactive and the body's metabolic rate speeds up causing fatigue, palpitations, shaking and weight loss. During thyroid radiation treatment, a single dose of radioactive iodine is swallowed, which enters the blood stream and is taken up by thyroid cells. Radiation from the iodine destroys thyroid cells, so that the gland becomes less active, and the same procedure may be used as a thyroid cancer treatment.
When the thyroid gland becomes overactive, the condition is known as hyperthyroidism. Most commonly the cause of the disease is a problem with the body's immune system, where the body attacks its own cells. In the case of hyperthyroidism, it is cells in the thyroid which are being attacked, and the gland responds by working harder and producing more hormones. While drugs can sometimes be used to treat the condition, it often returns, and thyroid radiation treatment offers a more permanent solution. As the therapy targets cells in the thyroid it can also be used to treat certain types of thyroid cancer, either following surgery to remove the gland or when cancer has recurred or spread.
Before thyroid radiation treatment, it may be necessary to follow a diet low in iodine, to maximize the amount of radioactive iodine taken up by the thyroid. Certain medications may need to be stopped a few days before the procedure. For thyroid cancer treatments, a synthetic hormone known as recombinant human TSH may be used to stimulate thyroid cancer cells, encouraging them to take up the radioactive iodine.
During thyroid radiation treatments, radioactive iodine is swallowed in the form of a pill or liquid. The iodine is absorbed in the gut and passes into the blood, where it circulates until it is taken into the thyroid gland, and, in the case of cancer, into thyroid cancer cells. Radiation from the iodine destroys the cells and a certain amount of radioactive iodine remains in the body, being slowly removed in urine and sweat.
Following thyroid radiation treatment, it is usually necessary to keep some distance away from other people for a time, which varies according to the dose of radioactivity received. After treatment for hyperthyroidism, it is typically necessary to keep others at greater than an arm's length away and to avoid pregnant women and children for a number of days. Thyroid radiation treatment for cancer may require being confined to a room for several days. Drinking plenty of fluid and urinating frequently both help flush the radioactive iodine out of the body. Thyroid radiation treatment does not have many side effects, but nausea, sore throat and swollen salivary glands may occur.