Radioactive iodine, also called RAI, is an isotope produced by fission of uranium atoms. Unlike stable iodine, radioactive iodine decays over time, and emits beta particles during decay. RAI is among the most commonly used radionuclides, and has several applications in the medical field, according to the U.S. Environmental Protection Agency.
Diagnosis
RAI, typically in the form of iodine-123, aids in diagnosis of thyroid problems without need for invasive surgery. Through administering RAI in capsule or liquid form, specialists can determine thyroid function by measuring the amount of RAI absorbed by the thyroid over a time, usually between six and 24 hours, according to Drugs.com. A specialist uses a gamma probe to scan the thyroid for RAI uptake.
Thyroid Cancer Therapy
Iodine-131, a form of RAI, may benefit patients with thyroid cancer. This form of RAI can destroy cancerous thyroid cells not removed by surgery, and may help destroy cancer cells that have spread from the thyroid to other areas of the body, according to the American Cancer Society. Dosages of RAI used to treat thyroid cancer are typically higher than those used for detection and diagnosis of thyroid disorders.
Side Effects
Although RAI may offer benefits for the treatment of thyroid cancer, it may cause side effects when taken in doses sufficient for cancer treatment. You may experience stomach upset and nausea after RAI treatment, according to the American Cancer Society. Other possible side effects include dryness in your mouth, tenderness or pain in your neck, swelling of your salivary glands, dry eyes and perceived changes in food taste. There are no known side effects of taking RAI at doses required for medical imaging, according to Drugs.com.
Considerations
Check with your doctor before taking RAI if you are allergic to shellfish or iodine -- you may not be able to take RAI for thyroid imaging or cancer treatment. Repeated treatments of RAI may lower sperm count or cause infertility in men, according to the American Cancer Society. RAI may also cause irregular menstruation in women. RAI treatments may slightly increase your risk of developing leukemia; however, this is a rare complication.
