Positron Emission Tomography (PET 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.

About Positron Emission Tomography (PET) Scans

The energy emitted from the injected or injested radioactive material is captured in images.

With a PET scan, the patient receives a radioactive version of a substance that is often normally used by the body, such as glucose. This tracer travels through the body and is used by cells similar to how the non-radioactive version would be. The type of radiation emitted by PET tracers is different from other nuclear medicine tracers, but they are also very safe and the amount of radiation involved is similar to that of other nuclear medicine and diagnostic x-ray exams.

The PET scanner detects the location and concentration of the tracer throughout the body. That information is displayed in three dimensional images that are analyzed by a radiologist. The radiologist can identify abnormalities in the distribution and utilization of the tracer that indicate disease. Cancer cells, for example, will take up glucose differently from regular cells. This difference can be seen on the PET scan images.

Following are some of the reasons for obtaining a PET scan in patients with known or suspected disease.

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  • Differentiate benign from malignant tumors
  • Stage or restage cancer by determining extent of disease
  • Assess effectiveness of therapy
  • Localize tumor in patients with suspected recurrence of cancer


  • Differentiate early Alzheimer's from other dementias
  • Localize seizure foci in patients with epilepsy
  • Evaluate malignancy of brain tumors


  • Detect and assess the presence and severity of coronary artery disease
  • Detect the presence of viable heart tissue (assess potential benefit of heart surgery)

Infection Diseases

  • Localize source of infection or fevers
  • Detect the presence of infection or inflammation


Most PET scans now also involve performing a CT scan at the same time. The same scanner can create and combine both PET and CT images while the patient remains still. This technology known as PET/CT offers the best of both worlds by fusing form (CT) and function (PET) together.

Risks Involved in a PET Scan

The risks involved in a positron emission tomography 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 during the injection or 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 PET scan, please call the hospital where the exam will be performed.

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

Insurance Coverage

PET scans 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
  • Diabetic
  • Any recent infection
  • Claustrophobic
  • Allergies to medications, contrast dyes, or latex

Preparation Guidelines

The preparation for a PET scan depends on the type and purpose of the scan that is ordered. Following is general information for whole-body PET scans using radioactive glucose. You may receive additional or differing guidelines based on your specific situation. Please contact the hospital where you will have the exam if you have any questions.

  • Do not eat or drink anything (except for water) for 4 hours prior to your exam. This includes chewing gum, candies, cough drops, cigarettes, and tobacco products.
  • If you are diabetic, contact the hospital for instructions regarding your diabetes medications.
  • Avoid strenuous exercise 24 hours prior.
  • Wear warm, loose, and comfortable clothing free of any metal to the exam.
  • Bring the most current radiology results related to the PET/CT scan 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.

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

PET scans vary depending on the type and purpose. However, here is generally what will happen during a whole body scan using radioactive glucose:

  1. You will complete some paper work upon arrival and a technologist will ask you questions about your relevant medical history.
  2. You may be asked to drink oral contrast material for certain exams.
  3. An intravenous line will be started.
  4. The radioactive tracer will be injected through the IV line and you will be asked to remain quiet and relaxed in a recliner chair for about 60 minutes while the tracer circulates through your system.
  5. Before scanning you will be asked to empty your bladder.You will be taken into the exam room and a technologist will help position you on the scanner table.
  6. Sedation will be given if ordered by your physician.
  7. The table will slide into the ring-shaped scanner. A short CT scan will be performed first, followed by a longer PET scan. It is extremely important not to move any part of your body during the scan to avoid blurring the images.

The images will take 30 to 45 minutes to complete.

The technologist will not stay in the room during the scan, but you can speak with him or her throughout the exam by intercom.

Additional Measures for Children

Up to two adults may be in the nuclear medicine room with your child.

After the Exam


You can return to your normal activities immediately after your PET scan. Drink plenty of fluids to help flush the radioactive material from your body. Depending on the exam, you may be asked to limit your exposure to children and pregnant women for 12 hours afterwards.

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 PET scans 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 PET scans. 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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