Alternative Names nuclear thyroid scan, radioactive iodine uptake scan
Definition This procedure is used to see if the thyroid gland is working properly. The thyroid gland is located in the neck just below the Adam's apple and makes hormones that are important in metabolism.
Who is a candidate for the procedure? A thyroid scan is usually done when a lump is felt in the thyroid gland or when there is an abnormal increase or decrease of thyroid hormone levels in the blood.
How is the procedure performed? The person is asked to either drink a liquid or take a pill that contains radioactive iodine. The radioactive iodine goes into the thyroid gland over the next several hours. About four hours after taking the iodine, the person is asked to lie down on a table below a special camera that can detect the radioactive material. While the person lies very still, the camera takes pictures of the thyroid gland. It takes about 30 to 60 minutes to take all the required pictures. Usually, the person is asked to come back 24 hours later to have a second set of pictures taken, which only takes about 5 minutes.
The pattern of the pictures can tell the doctor what may be wrong with the thyroid gland. Some areas of the gland may take up more radioactive iodine than others. The pattern of uptake often suggests a specific disease, which can guide the treatment. For example, the thyroid scan may reveal an area that is suspicious for thyroid cancer. In this case, surgery may be needed to remove it. Or the scan may show that the thyroid gland is overactive and will respond to medications. The doctor will discuss the results and treatment options.
What happens right after the procedure? The person can go home or back to their hospital room and return to their normal activities.
What happens later at home? The radioactive iodine is usually gone from the body within 48 hours. The total dose of radioactive material is small and no special precautions are required.
What are the potential complications after the procedure? The total dose of radiation is quite small and hardly ever causes complications. Rarely, allergic reactions to the radioactive tracer can occur. People should tell the doctor about any allergies they may have, especially to iodine or shellfish. Sometimes the person may have an odd taste in the mouth or nausea from the radioactive iodine.
Author: Adam Brochert, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
