What is PET/CT?

PET/CT combines the functional information from a Positron Emission Tomography (PET) exam with anatomical information from a Computed Tomography (CT) exam into one single exam.

A PET scan detects changes in cellular function—specifically, how your cells are utilizing nutrients like 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.

The PET exam pinpoints metabolic activity in cells and the CT exam provides an anatomical reference. When these two scans are fused together, your physician can view metabolic changes in the proper anatomical context of your body.

Why Might I Need This Exam?

Your PET/CT imaging results may have a major impact on your diagnosis and course of treatment selected by your physician. A PET/CT study not only helps your physician diagnose a problem, it also helps your physician predict the likely outcome of various therapeutic alternatives, pinpoint the best approach to treatment, and monitor your progress.

If you are not responding as well as expected, you may be switched to an alternative therapy. Ask your physician what he or she hopes to learn from your PET/CT exam.

What Can I Expect?

During the Exam

When you arrive at the Avon Medical Center for your PET/CT appointment, our team will review your history and any past exams. 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 (two hours) 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 relax and wait 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 PET/CT scan should last between 20 and 45 minutes. The exam can vary depending on what we are looking for and what we discover along the way. Plan to spend two to three hours with us.

After the Exam

After your PET/CT exam, you may return to the designated area as soon as the exam is complete. 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. In the meantime, we'll begin preparing the results for review by our interpreting physician, and then by your physician, who will tell you what we've learned.

Be assured that PET/CT exams are a safe and effective diagnostic procedure. The radiopharmaceuticals used in PET do not remain in your system long, so there's no reason to avoid interacting with other people once you've left. To be extra safe, wait for a few hours before getting too close to an infant or anyone who is pregnant.

Preparing for a PET/CT Exam

Below are common instructions Hendricks Regional Health gives our patients before their exam. Always follow the specific instructions given to you by your provider, as they know your medical condition and history best.

General Information

• There is a max weight of 500 lbs. on the PET/CT.
• Patients will need a pre-certification for most insurances (our hospital accepts most insurances).
• Avoid strenuous physical activity for 24 hours prior to exam (heavy lifting, vigorous exercise, etc.).
• Please let us know if you might be pregnant or are breastfeeding.

What to Bring/Wear

• If applicable, bring outside films and reports: CT, MRI and PET/CT.
• Do not wear anything metallic (underwire bras, belts, zippers, buttons, etc.).

Food & Drink Restrictions

• No nicotine use or chewing gum the day of the exam.
• Do not eat or drink anything EXCEPT water 6 hours prior to the exam.
• If you are diabetic, let us know ahead of time so we can work with your physician to determine the safest possible way for you to prepare for your exam. No insulin for six hours prior to the exam.
• We encourage you to drink approximately 32 ounces of water about 1 to 2 hours prior to your exam.
• When taking your morning medication, only drink water. You may eat a few soda crackers if you've been advised not to take your medications on an empty stomach.
• Meals eaten the day prior to your exam should be low-carbohydrate, high-protein. Please AVOID breads, pastas, cereals, grains, fruit, candy and other high carbohydrate/sugar foods. Download our handout for more PET/CT dietary information: PET/CT Diet Recommendations (PDF) »