PET Scan

Positron emission tomography, also called PET imaging or a PET scan, is a type of nuclear medicine imaging.

Nuclear imaging tests are noninvasive procedures that help your doctor diagnose and evaluate medical conditions. In these tests, you receive a very small amount of a safe radioactive material designed to go to a specific place in your body. Then, a special camera—a gamma camera— tracks the path of the material, called a radiotracer, to show how your organs and tissues work.

To see how well your organs are working, your doctor may recommend positron emission tomography (PET) at Pardee Outpatient Radiology. This nuclear imaging test will use positron emission tomography to create three-dimension images by taking multiple scans of your body at different angles with gamma cameras, but they use different types of radiotracers. The type of scan you receive will depend on your specific condition.

Modern PET imaging combines nuclear medicine images with CT imaging in the same exam (PET/CT). This combination allows your doctor to connect and interpret information from two different exams on one image. The molecular functional imaging of PET is combined with anatomical and structural data from CT. This leads to more precise information and a more exact diagnosis.

When Are PET or PET/CT scans used?

Nuclear imaging tests show the structure and function of your internal organs, tissues, bones and circulatory and nervous systems. The procedures provide detailed information that can help your doctor accurately diagnose a condition very early in the progression of a disease, so you can get the best possible treatment. Your doctor may order a PET scan to:

  • Check brain function and diagnose brain disorders
  • Diagnose cancer and see how it’s responding to treatment
  • Detect conditions of the heart, liver and other internal organs
  • Evaluate bone conditions, including broken bones
  • Identify sites of seizures, Parkinson’s disease and Alzheimer’s disease

Tell your doctor if you’re pregnant or breastfeeding. He or she will tell you if it’s OK to get a nuclear imaging test.

Nuclear Imaging Scan: What to Expect

You’ll receive specific instructions on how to prepare for your procedure. Follow them carefully to help your doctor get the best, most accurate images.

Before your scan, you’ll be asked to receive an injection, swallow or inhale a radiotracer. Depending on your specific test, you may need to wait a few minutes or a few days for the tracer to travel through your body.

When it’s time to take the images, you’ll be positioned on an examination table and a scanner will take a series of images. Some machines rotate around you; others may require you change positions between images. You’ll need to stay very still while pictures are being taken to avoid blurry images.

Some exams take as little as a half-hour; others are conducted over several days.

How to Prepare

A few days before your appointment, you’ll receive a phone call with instructions on how to get ready for your test.

You may need to:

  • Avoid eating or drinking for a short time
  • Let us know if you’re pregnant or breastfeeding
  • Tell us your medical history, current medications, and allergies to medications
  • Stop taking certain medications temporarily

If you have diabetes, you may receive special instructions regarding food, drink, and medications. We’ll check your blood sugar before the exam.

What to Expect

You’ll receive a radioactive tracer through a vein (intravenously). It’s a special type of substance (usually glucose, or sugar) that collects in cells that use a lot of energy, such as cancer cells. The tracer shows up on a special type of camera called a gamma camera.

Except for intravenous injections, most nuclear medicine procedures are painless. Reports of significant discomfort or side effects are rare.


A board-certified radiologist will review your results and give a report to your doctor who ordered the exam. Your doctor will share the results with you and discuss the next steps.