A thyroid scan uses a radioactive iodine tracer to examine the structure and function of the thyroid gland. This test is often done together with a radioactive iodine uptake test.
Scan - thyroid; Radioactive iodine uptake and scan test - thyroid; Nuclear scan - thyroid
How the Test is Performed
The test is done in this way:
- You are given a pill that contains a tiny amount of radioactive iodine. After swallowing it, you wait as the iodine collects in your thyroid.
- The first scan is usually done 4 to 6 hours after you take the iodine pill. Another scan is usually done 24 hours later. During the scan, you lie on your back on a movable table. Your neck and chest are positioned under the scanner. You must lie still so that the scanner gets a clear image.
The scanner detects the location and intensity of the rays given off by the radioactive material. A computer displays images of the thyroid gland. Other scans use a substance called technetium instead of radioactive iodine.