What is a PET/CT Exam?

A PET/CT combines the functional information from a Positron Emission Tomography (PET) exam with anatomical information from a Computed Tomography (CT) exam in one single exam. A PET scan detects changes in cellular function- specifically, how your cells are utilizing nutrients such as sugar and oxygen. Since these functional changes take place before physical changes occur, PET can provide information that enables your physician to make an early diagnosis.

The advantage of CT is its ability to take cross sectional images of your body.  These are combined with the information from the PET scan to provide more anatomic details of the metabolic changes in your body. 

When these two scans are fused together, your physician can view metabolic changes in the proper anatomical context of your body. 

What do I Need to do to Prepare for the Exam?

Please do not eat or drink anything except water for 6 hours prior to the exam.  If you are a diabetic patient, contact your physician to determine the safest way to prepare for your exam.  The meal prior to your 6-hour pre-exam fasting period should be high-protein and low-carbohydrate.  Please avoid breads, pastas, cereals, grains, fruit, candy, and other high carbohydrate/sugar foods.  We encourage you to drink approximately 32 ounces of water about 1 to 2 hours prior to your exam.  Please do not use nicotine or chewing gum the day of the exam.  Avoid strenuous physical activity for 24 hours prior to the exam. 

What Should I Expect when I Arrive?

Please use the Emergency Department entrance and register at the desk.  The PET technologist will be notified of your arrival and will escort you to the examination area when ready.  The PET technologist will review your history and any past exams.  The technologist will explain the scan, take your height and weight, and answer any questions or concerns that you may have about the exam.  In addition, please inform the technologist if you might be pregnant or are currently breast feeding. 

What will I Experience During the Exam?

For the PET portion of the exam, you will receive an injection of radioactive material similar to what is used for bone scans and other nuclear medicine exams.  This is a radioactive tracer that must pass multiple quality control measures before it is used for any patient injection.  PET radiopharmaceuticals lose their radioactivity very quickly and only very small amounts are injected.  In all cases, the majority of radioactivity will be eliminated from the body approximately 6 hours after injection.

After your injection, you will be asked to wait and relax in our injection suite for one hour while the radiopharmaceutical distributes.  During the exam, you will lie very still on a comfortable table that will move slowly through the scanner as it acquires the information needed to generate diagnostic images. 

The actual PET/CT scan should last between 20 and 45 minutes.  The exam length may vary depending on what we are looking for and what is discovered along the way.  Plan to spend two to three hours with us.

Who will be in the Exam Room with Me?

The registered PET/CT technologist will be performing this exam for you and will be available to answer any questions or concerns that you may have throughout your scan.

What do I need to do After the Exam?

Unless you’ve received special instructions, you will be able to eat and drink immediately.   Drinking lots of fluids soon after the exam will help remove any of the radiopharmaceutical that may still be in your system. 

When will I receive the Results of the Exam?

You will receive your results from your ordering physician.  You may receive a phone call or have a follow up appointment with your physician.  If you are unsure of how you will receive your results or have questions regarding your results, please contact your physician’s office.