Radioiodine therapy is a nuclear medicine method used to treat diseases of the thyroid gland. This procedure is particularly effective for hyperthyroidism, goiter, or thyroid carcinoma.
What is radioiodine therapy?
Radioiodine therapy is a nuclear medicine method used to treat diseases of the thyroid gland. Radioiodine therapy is used to treat problems with the thyroid gland. This butterfly-shaped organ, located in the throat area in front of the trachea, is responsible for storing iodine and producing thyroid hormones. Thyroid hormones are very important for the body’s energy metabolism, and diseases of this organ are usually accompanied by a variety of symptoms throughout the body. In radioiodine therapy, the patient is administered the radioactive isotope of the element iodine. This enters the blood through the digestive tract and accumulates in the thyroid gland. The part of the radioiodine that is not stored in the thyroid gland is excreted by the kidneys within a few days and does not pose a health problem for the body. Radioiodine therapies are used for various thyroid diseases. These include benign growths of the thyroid gland, for example, which release hormones independently of the actual cells of the thyroid gland, or the autoimmune disease Graves’ disease, which leads to goiter formation.
Function, action, and goals
Radioiodine therapy is particularly effective for hyperthyroidism. Hyperthyroidism is caused by autonomy of part of the thyroid cells. These parts of the tissue produce an excess of hormones because they are not subject to general control. The goal of radioiodine therapy is to kill these autonomously functioning cells in the thyroid gland so that they can no longer produce excess hormones. The radioiodine stored in the thyroid gland decays, emitting beta radiation, which destroys the surrounding tissue. This mode of action is used in radioiodine therapy to kill those cells in the thyroid gland that produce the excess hormone. The areas of thyroid tissue that release too many hormones and cause the hyperfunction symptoms in the patient are very active and have a fast metabolism, the radioiodine mainly accumulates in such cells and destroys them. Healthy thyroid tissue is not damaged. Therapy with radioiodine can also be promising for diseases that do not result in hyperthyroidism. These include thyroid carcinoma or thyroid enlargement. The principle of action of the therapy is the same as for hyperthyroidism. Thus, radioiodine treatment of thyroid enlargement, even without hyperthyroidism, can lead to a significant reduction in the size of the goiter and the associated symptoms. In many patients, the goiter can even be completely eliminated. Thyroid carcinomas can be treated very effectively with the radioiodine method. Most degenerated cells accumulate iodine and can be killed by beta radiation as they decay. In cases of cancer, the patient is given a higher dose of radioiodine than in cases of hyperthyroidism. Often this therapy is used after partial surgical removal of thyroid cancer to allow removal of the remaining degenerated tissue. In many cases, thyroid cancer can be cured this way.
Risks, side effects, and hazards
Treatment of the thyroid gland with radioiodine is not a dangerous therapy and very rarely has undesirable side effects. Nevertheless, certain precautions are necessary because of the radioactivity of the iodine used. For example, patients are urged to drink enough during the first two days after taking the radioiodine because the iodine that is not enriched in the thyroid gland is excreted through the urine and this should happen as quickly as possible so as not to unnecessarily endanger the urinary bladder. In addition, it is recommended to increase salivation, for example by sucking acid drops, because a small amount of radioactive iodine is also excreted through saliva. To avoid endangering others with increased radiation exposure, patients must be admitted to a specially designated infirmary during radioiodine therapy. Radiation exposure to the patient’s internal organs is low.The radioiodine decays rapidly, emitting mainly beta radiation. This radiation has a very short range, in the millimeter range, and therefore hardly affects other organs. Studies show that there is no increased cancer mortality rate in people treated with radioiodine than in the rest of the population. In rare cases, side effects may occur directly during or after therapy. However, these are usually not dangerous and can be well treated. The most common acute side effect is inflammation of the thyroid gland, which can occur a few days after the start of therapy. However, this can be treated quickly and effectively with anti-inflammatory and analgesic medications and is usually harmless.
