Thyroid scintigraphy, also known as a thyroid scan, is a nuclear medicine imaging procedure used to evaluate the structure and function of the thyroid gland. It involves using a radioactive tracer to create images that show the size, shape, and position of the thyroid, as well as how well it’s functioning. This scan can help diagnose and manage various thyroid conditions, including overactive (hyperthyroidism) or underactive (hypothyroidism) thyroid, thyroid nodules, and even thyroid cancer.
Here’s a more detailed breakdown:
How it works:
Radioactive tracer:
A small amount of radioactive material, often iodine-123 or technetium-99m pertechnetate, is injected intravenously or taken orally.
Uptake:
The thyroid gland absorbs the radioactive tracer, and its function is determined by how much tracer is taken up and how quickly.
Imaging:
A special camera called a gamma camera detects the radioactive tracer and creates images of the thyroid gland.
Analysis:
The images are then analyzed by a nuclear medicine physician to assess thyroid function and structure.
Purpose and uses:
Diagnosing thyroid conditions:
Scintigraphy can help identify various thyroid problems, including hyperthyroidism, hypothyroidism, and thyroid nodules.
Assessing thyroid nodule behavior:
It can help determine if a nodule is “hot” (functioning properly and benign) or “cold” (non-functioning and potentially cancerous).
Guiding treatment:
The results can help guide treatment decisions, such as medication or surgery.
Monitoring thyroid function:
It can also be used to monitor the effectiveness of treatment for thyroid conditions.
Locating ectopic thyroid tissue:
In some cases, it can help locate thyroid tissue outside of the normal location, such as in the chest.
Procedure:

1. Preparation:
   No special preparation is usually needed, but you may be asked to avoid certain medications and foods before the scan.
2. Injection/Oral administration:
   The radioactive tracer is either injected intravenously or taken orally.
3. Waiting period:
   You may need to wait several hours for the tracer to be absorbed by the thyroid.
4. Imaging:
   You will lie on a table while the gamma camera takes images of your thyroid gland.
5. Interpretation:
   A nuclear medicine physician will interpret the images and provide you with the results.
   Benefits and Risks:
   Benefits:
   Thyroid scintigraphy is a relatively safe and non-invasive way to assess thyroid function and structure.
   Risks:
   The main risk is the potential exposure to low levels of radiation from the radioactive tracer. However, the amount of radiation is typically very low and considered safe.
   In summary, thyroid scintigraphy is a valuable tool for diagnosing and managing various thyroid conditions. It helps doctors assess the function and structure of the thyroid gland, guiding treatment and monitoring disease progression.