Thyroid Uptake and Scan

General Information | Scheduling, Insurance and Preparation | What to Expect

General information General Information

About Nuclear Medicine

Nuclear medicine exams image bodily function rather than anatomy. They can be useful in finding problems that are not obvious by looking at the structure of an organ or tissue. This is done with the use of small amounts of radioactive materials, also known as tracers. Each tracer is designed to be attracted to specific organs or types of body tissue. Special cameras that can map the distribution of the radioactive tracer create images which are studied by radiologists.

Nuclear medicine scans are very safe. Nuclear medicine has been used in newborns and children for more than four decades and even longer in adults. There are no known long-term adverse effects from such low-dose exams.

Bone scans are one of approximately 70 types of nuclear medicine exams interpreted by RIA radiologists.

About Thyroid Uptake and Scan

A thyroid uptake and scan, also known as a radioactive iodine uptake test (RAIU), is a nuclear medicine exam in which the patient receives an oral dose of a radioactive iodine that is absorbed by thyroid tissue. The amount of radioactivity taken up by the thyroid is measured and images of the thyroid are also obtained. Thyroid uptake scans are used to measure thyroid function, to determine if there are any nodules present, or to determine the degree of function in known nodules.

Risks Involved in a Thyroid Uptake and Scan

The risks involved in a thyroid uptake and scan are minimal. They include the following:

  • Radiation exposure; however, a very small amount of radioactive material is used and the radiation exposure is well below the level that generally causes adverse affects.
  • Allergic reactions to the radioactive material; however, this is rare.
  • Discomfort while laying on the table for the required amount of time for the scan.

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Scheduling, Insurance and Preparation Scheduling, Insurance and Preparation

Exam Locations

The exam is performed at the following Radiology Imaging Associates partner hospitals in the Denver, Colorado area:

Call the hospital to schedule.


To schedule a thyroid uptake and scan, please call the hospital where the exam will be performed.

  • Medical Center of Aurora
  • Littleton Adventist Hospital
  • Porter Adventist Hospital
  • Sky Ridge Medical Center
  • Swedish Medical Center

Insurance Coverage

Radioactive iodine uptake tests are usually covered by insurance when ordered by a physician. Check with your insurance company to be sure. Please bring your insurance card with you to your exam.

Conditions to Let Us Know About

In advance of your exam, let your scheduler, technologist, or radiologist know if any of the following circumstances apply to you (or your child):

  • Pregnant or may be pregnant
  • Breastfeeding
  • Claustrophobic
  • Allergies to medications, contrast dyes, or latex

Preparation Guidelines

Following are the general preparation instructions for this exam. You may receive additional or differing guidelines based on your specific situation. Please contact the hospital at which you will have the exam if you have any questions.

  • Stop taking any T4 thyroid hormones for at least 4 weeks or T3 thyroid hormones for at least 2 weeks before your exam. (Check with your doctor to ensure it’s safe.)
  • Stop taking any antithyroid medications at least 4 days before your exam. (Check with your doctor to ensure it’s safe.)
  • You must not have had any x-ray studies involving IV contrast (e.g., IVP, CT scan) for at least 4 weeks before your exam.
  • Do not eat for 2 hours before and 2 hours after you receive the radioactive iodine
  • Bring the most current radiology results related to your thyroid, if not done at an RIA partner hospital or Invision Sally Jobe.
  • If the patient is your child, bring any of the following items to increase his or her comfort: CDs, movies, pacifiers, special blankets, and stuffed toys.

If sedation is required, you must adhere to these food restrictions:

  • No solid food (including baby food and formula for babies) for 6 hours prior to the exam.
  • No liquids, including water, breast milk, and juice, for 2 hours prior to the exam.

Support for Children

If your child is having the exam, it is important that you provide emotional support for him or her before and during the procedure. If your child is old enough to understand, explain the procedure to him or her. Let him or her know that the exam won’t hurt and that he or she will have to lie very still throughout the exam. Also reassure your child that you will be able to remain in the room during the exam.

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What to Expect What to Expect

During the Exam

Nuclear medicine exams use small amounts of radioactive materials and a special camera to examine body function rather than anatomy.

A nuclear medicine thyroid uptake and scan is a two part exam. Here is generally what will happen:

  1. You will complete some paper work upon arrival.
  2. For the first part of the exam, a technologist will give you a small dose of radioactive iodine by mouth in capsule form.
  3. You will return 6 hours later.
  4. A technologist will take radiation measurements of your neck and thigh for 1 minute.
  5. You will then be placed on a scanner table and a gamma camera will be used to take a series of images of the thyroid lasting about 40 minutes.
  6. In some cases, you may be asked to return the following day for another radiation measurement of your neck (no images).

Additional Measures for Children

If the patient is a child, the following additional measures may be taken:

  • Up to two adults may be in the nuclear medicine room with your child.
  • If the child requires sedation (usually for children under the age of 10), it will be given orally before the scan.

After the Exam


You can return to your normal activities immediately after the exam. Drink plenty of fluids to help flush the radioactive material from your body.

Sedated Children

If the patient is a child and was sedated, he or she may be groggy after the exam. The sedation drug may stay in your child’s system throughout the day. Please anticipate a change in your child’s eating and sleeping habits for the remainder of the day. Although it isn’t essential that your child eat, it is important that your child drink fluids throughout the day. He or she should be back to normal the following day.

Exam Results

A board-certified radiologist experienced in the interpretation of radioactive iodine uptake tests will analyze the data and results from your exam. If the patient is a child, the exam data will be analyzed by a radiologist experienced in the interpretation of pediatric radioactive iodine uptake tests. The results will be reported to your physician. Your physician will pass the results onto you.

During the exam, our radiologists and technologists will be happy to answer questions about the exam itself; however, they will not immediately provide you with the results of your exam.

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