Thyroid scan
Alternative names:
nuclear scan - thyroid; radioactive iodine screening test, thyroid; RAUI; scan - thyroid
How the test is performed:
You are given radioactive iodine to drink (or in pill form) and then must wait until the iodine collects in the thyroid. The first scan is usually 4 to 6 hours after the iodine has been ingested, and another scan may be taken 24-hours later.
After the iodine has been absorbed by the thyroid, you lie on your back on a gantry (movable table) with your neck and chest positioned under the scanner. The scanner detects the location and intensity of the gamma rays emitted by the iodine. During this part of the procedure, you must lie still to enable the scanner to get a clear image.
Next, the information is sent to a computer that displays a 2-dimensional image of the thyroid and any nodules that have absorbed the iodine. The image is recorded in the computer and can be reproduced on X-ray film or a computer printout.
How to prepare for the test:
You must sign a consent form. Fasting overnight is a usual requirement. Consult the health care provider if you are taking any medications that may need to be regulated (such as thyroid medication and anything with iodine in it). Remove jewelry, dentures, or other metals, because they may interfere with the image.
Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:
How the test will feel:
The iodine mixture may cause slight nausea when you take it.
Some patients find remaining still during the test uncomfortable.
Why the test is performed:
When thyroid cancer or nodules are suspected.
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