A nuclear thyroid scan is recommended in the presence of suspected ectopic thyroid or retrosternal thyroid, to rule out autonomous functional thyroid nodules.
A nuclear thyroid scan uses a contrast agent to visualize the thyroid tissue, which in turn reflects the location, size, shape, blood flow, function, and structure of the thyroid gland. Because the thyroid gland is the only tissue capable of taking up iodine, the rate of movement and dose of iodine in the body, measured using radioactive iodine (or technetium) as a tracer, can reflect the condition of the thyroid gland.
Thyroid nuclear scanning is recommended in the presence of suspected ectopic or retrosternal thyroid; to rule out autonomous functional thyroid nodules in patients with low thyroid-stimulating hormone in iodine-deficient areas; to look for metastatic foci of thyroid cancer; and to assess the weight of the thyroid gland before iodine 131.
It is important to note that the test is not recommended for special populations such as pregnant and lactating women.
If you are not sure whether you need a nuclear thyroid scan or not, you can go to the hospital and ask your doctor to make a judgment.