What the risks are:

The amount of radioactivity is very small, and there have been no documented side effects. The amount of iodine used is less than the amount of iodine in a normal diet. However, as with any radiation exposure, this test is not recommended for women who are pregnant or breastfeeding.

People with a history of allergy to dietary iodine or shellfish may not be able to have this test. A history of allergy to iodine (contrast dye) does not necessaily mean you can't have this test. Talk to your health care provider.

Special considerations:

The radioactive iodine leaves your body through your urine. You may need to take special precautions, such as flushing twice after urinating, for 24 - 48 hours after the test. Ask your health care provider or the radiology/nuclear medicine employee performing the scan.