20/09/2016
Thyroid Scan:
The thyroid imakes and stores essential hormones that help regulate the heart rate, blood pressure, body temperature, and the rate of chemical reactions (metabolism) in the body. It is located in the neck region.
The thyroid gland takes up iodine. In a thyroid scan, iodine is labeled with a radioactive tracer, and a SPECT Gamma camera is used to measure how much tracer is absorbed from the bloodstream by the thyroid gland.
When is thyroid scanning helpful?
A thyroid scan reveals quantum of iodine uptake by the thyroid gland. The scan provides information on the size and shape of the gland as well as the overall activity of the gland (is the thyroid overactive or under active?). It can detect inflammation of the thyroid gland (thyroiditis), presence and degree of overactivity of the gland (hyperthyroidism ).
Thyroid scanning is helpful in evaluating thyroid nodules & can also provide information on specific areas within the thyroid gland and can help to determine whether any localized areas are hyper functioning or under functioning. In this case spots appear on the image corresponding to areas that take up iodine differently from the rest of the gland.
In addition, thyroid scanning can be done to help determine if thyroid cancer has spread beyond the bed of the thyroid in the neck.
How is the thyroid scan performed?
A thyroid scan is an outpatient procedure usually done in the nuclear medicine section of a hospital. If you have a thyroid scan, you will be asked to take a drink containing iodine. You will then wait for the iodine to be taken up by the thyroid - usually about 4 hours. At this time you lie under a Gamma camera, and it will take pictures which correlate directly to the amount of iodine taken up by the thyroid. This is done by counting the intensity and location of the gamma rays emitted by the radioactively labeled iodine. You can then leave the center, and return in 24 hours to have a second scan performed in the same manner.
