Thyroid scan

Thyroid Scan

A Thyroid Scan is an imaging test typically used to help diagnose problems involving the thyroid gland. It is a type of nuclear medicine imaging test that produces pictures of the inside of the body that can help in the diagnosis of a variety of thyroid problems.


When undergoing this type of procedure, often times you will be asked to avoid eating and drinking for up to 8 hours prior. Your healthcare provider may ask you to stop taking certain medications for up to 48 hours prior. You may be asked to stop taking iron supplements, calcium supplements, and any medications such as thyroxine that may specifically affect how the thyroid works.


During the scan, a very small amount of radioactive material will be injected or swallowed. A special gamma camera then tracks the radioactivity as it moves through the body and is taken up by the thyroid. The camera then takes pictures of the distribution of the radioactivity in the thyroid.

Types of Thyroid Scans

  • Iodine-123 Thyroid Uptake Scan
  • Technetium Tc-99m Sestamibi Scan


The risks of a thyroid scan are minimal — most involve the amount of radiation exposure the test will expose the person to. The amount of radiation exposure is much lower than that of a chest X-Ray, however, and the risks of any of the types of thyroid scans are minimal.

Why Is A Thyroid Scan Performed?

A Thyroid Scan is typically performed to help diagnose or assess the size, shape, or function of the thyroid gland. It is used to diagnose problems such as thyroid cancer, thyroid nodules, or an overactive or underactive thyroid. A Thyroid Scan can also be used to stage thyroid cancer and to measure the uptake of thyroid hormone replacement therapy.

When Is A Thyroid Scan Performed?

A Thyroid Scan is typically recommended when a person has symptoms or lab tests that suggest a problem with the thyroid. It is also recommended as a follow-up test to confirm thyroid status after certain treatments, such as surgery or radiation therapy.