This is general health information only and is not a substitute for advice from your GP or healthcare professional.
1. What is a thyroid uptake scan?
A thyroid uptake scan is a nuclear medicine test used to assess how well the thyroid gland is functioning. It measures how much radioactive iodine or a similar tracer is absorbed by the thyroid and provides images of the gland.
2. Why is a thyroid uptake scan performed?
It is commonly used to evaluate the cause of hyperthyroidism, distinguish between different thyroid conditions, and assess thyroid nodules. It helps determine whether the thyroid is overactive, underactive, or functioning unevenly.
3. How does the test work?
A small amount of radioactive tracer is swallowed or injected, which is taken up by the thyroid gland. A special camera then measures how much tracer is absorbed and creates images showing the distribution within the thyroid.
4. What conditions can it help diagnose?
It can help differentiate conditions such as Graves’ disease, toxic multinodular goitre, thyroiditis, and solitary “hot” or “cold” nodules. The pattern of uptake provides important diagnostic clues.
5. Is the radiation exposure safe?
The radiation dose used is low and generally considered safe for most adults. However, it is not recommended during pregnancy, and precautions may be needed for breastfeeding individuals.
6. How should I prepare for the test?
Preparation may include avoiding iodine-containing medications or supplements, certain foods, and contrast scans before the test. Your doctor will provide specific instructions based on your situation.
7. How long does the test take?
The test may be done over several hours or across two days, depending on the protocol. Uptake measurements are often taken at specific time points after the tracer is administered.
8. What do the results mean?
High uptake suggests an overactive thyroid, as seen in conditions like Graves’ disease. Low uptake may indicate thyroiditis or other causes where the gland is not actively producing excess hormone.
9. Are there any side effects?
Side effects are rare. The tracer is generally well tolerated, and allergic reactions are uncommon. Most of the tracer leaves the body naturally over time.
10. When should I discuss this test with my doctor?
You should discuss a thyroid uptake scan if you have symptoms of hyperthyroidism, abnormal thyroid blood tests, or thyroid nodules that require further evaluation.