Thyroid Scan/Thyroid Uptake

A thyroid scan is used to examine the relative function in different areas of the thyroid gland, with a special focus on the nodules compared to the other parts of the gland.

A thyroid uptake is used to help determine whether the thyroid function is overactive (hyperthyroidism) or underactive (hypothyroidism). The uptake is done at the same time as the scan.

What To Expect

For this exam, you will need to come to our imaging center two days in a row at about the same time on both days. On the first day, you will take an easy-to-swallow capsule that contains radioactive imaging material. Because specific measurements of the radioactivity in the capsule have to be made right before you take it, we cannot let you pick it up early to take later in the day.

Over the next 24 hours, the contents of the pill will absorb into your thyroid gland. You should not feel any effects at all, and adverse reactions are extremely rare.

On the second day, you will come back for the scan and uptake, which will take about one hour. You will have several opportunities to move around during that time if you need to.

When the exam is completed, the radiologist will review your images, prepare a written report, and discuss the results with your doctor. Your doctor will then explain the test results to you and discuss what further procedures, if any, may be needed.

A few things you need to know:

  • It is very important to remain still while you are being imaged, as movement may blur or distort your images.
  • There is no need to worry about the amount of radiation you will receive during the test. It is no more than what you would receive from similar x-ray procedures.
  • Be sure to tell your doctor if you are pregnant, think that you may be pregnant, or are a nursing mother.
  • Although adverse side effects are rare, you should tell the technologist if you feel lightheaded, nauseated, or if you have other symptoms during the exam.
  • The radioactive tracer will remain in your body for a short time and is cleared out through natural bodily functions. Drinking plenty of fluids before the exam and after the tracer injection helps eliminate the material more quickly.

After the test, you should be able to resume your normal daily activities immediately.

Patient Preparation

  • You should wait at least four weeks after having intravenous iodinated contrast before having your thyroid scan and uptake. This includes contrasts (sometimes called x-ray dye) that are used for heart catheterizations, CT scans, kidney x-rays, or intravenous urograms (IVPs), and angiograms.
  • You will need to discontinue your thyroid medication for a certain period of time ranging from several days to a month, depending on which medication you are taking. Exactly when you should stop taking your medication is usually established when you schedule your exam. If you do not find out then, please call and speak to our staff to find out when you should stop taking the medication.