Guide to Thyroid Imaging Tests
Women expecting to become ____________ within the next six months should not undergo imaging tests.
Hi, this is Dr. Michael Via, with Beth Israel Medical Center, Division of Endocrinology and Metabolism. I'm here with about.com to talk about the guide to thyroid imaging.When a thyroid condition is suspected, several tests are administered to establish a proper diagnostic. Some of these tests, such as the TSH test, are blood tests that are meant to assess levels of hormones produced by the thyroid.Oftentimes, these tests will need to be followed by imaging tests that can include radioactive iodine uptake test or RAIU and thyroid scan. These tests utilize tiny amounts of radioactive material to trace and determine certain aspects of thyroid function. Radioactive iodine tests are a branch of what is called nuclear medicine.Both procedures are usually done simultaneously. The patient is first asked to swallow the radioactive material. It's typically iodine, although injections of other materials may be used in some cases. These tracer substances naturally accumulate in the thyroid gland. Too much or too little concentration of radioiodine within the gland or in just specific portions of the gland may be useful in the diagnosis and indicate the area of concern.This scan is done with the patient lying down, with the neck stretched out, and the gamma camera is placed in the front of the neck to measure the amount radiation.Although the term "radioactive" often makes patients nervous, the dose administered is very small and is low enough to be safe. Pregnant or lactating women, or women considering pregnancy within the next 6 months should not, however, undergo these tests.People allergic to iodine can have the test done because the radioiodine that is used is administered in salt form. Just as patients with iodine allergies can safely consume iodine containing table salt, the radioiodine used in these tests ordinarily does not elicit an allergic reactions.Other thyroid imaging studies include ultrasound and computerized tomography, known as CT or "cat" scan.Ultrasounds don't make usage of radiation. A probe emitting high frequency sound waves, or ultrasounds, is swept along the neck in front of the thyroid. The echoes and reverberations of that sound are gathered and measured by a computer to produce a picture of the thyroid. Ultrasound test often produces the most revealing thyroid images.To find out more, go to About.com.