A PET/CT scan is a specialized exam combining PET (Positron Emission Tomography) and CT (Computed Tomography) to assess the metabolic activity of cells and provide anatomic localization, respectively. Patient Instruction Sheet for PET/CT

What will I experience during a 18F FDG PET/CT scan?

  • You may be asked to drink oral contrast material.
  • Your blood glucose level will be checked.
  • You will be injected with a small amount of a radiopharmaceutical, 18FDG (radioactive sugar), after which you will rest in a quiet room for approximately 60 minutes.
  • You will be asked to remain still during the exam, which lasts from 30 to 45 minutes.
  • You may resume your normal activities after the exam. Drink plenty of fluids to help flush any trace amounts of radioactive material from your body.
  • There is no danger to other travelers on public transportation following a PET/CT scan. However, some current radiation detectors in public areas such as airports or international borders can be inadvertently activated by even a small amount of radiation. If appropriate, it may be a good idea to obtain a letter from Great Lakes Medical Imaging stating you have undergone a PET/CT scan in case you are questioned.
  • A board-certified radiologist will interpret the results of your exam and share these results with your physician. Your physician will discuss the results with you.


  • Notify our staff prior to your exam if you are pregnant, may become pregnant, or are currently breastfeeding.
  • Wear comfortable clothing that does not contain metal or zippers. It is suggested that you wear warm (layered) clothing, even in the summer months.
  • Abstain from eating or drinking four hours prior to exam, except for water and medications.
  • Stay hydrated by drinking six to nine glasses of water the day prior to your exam, and continue to drink water up until your exam.
  • Eat a low-carbohydrate, high-protein diet 24 hours prior to your exam. (Diets should consist of less than five grams of carbohydrates per serving)
  • Suggested foods
  • Non-starchy vegetables (green leafy vegetables like spinach, broccoli, green beans, zucchini)
  • Fish, meat, eggs and cheese
  • If you are claustrophobic, you can schedule a time with our staff to look at the machine prior to your exam. You may also ask your physician to prescribe a single dose of relaxant for the day of the exam, if necessary. In this case, please arrange for transportation to and from our office.
  • Please allow two full hours in your schedule for your exam.


  • Do not wear jewelry, piercings or removable dental work.
  • Do not eat high-carbohydrate/sugar foods

Food to Avoid:

  • Cereals, pastas, breads and grains
  • Peas, corn, rice, potatoes and beans
  • All fruits, fruit juices and soda pop
  • Candy, mints, cough drops and gum
  • Alcoholic beverages and caffeinated drinks
  • Do not perform strenuous exercise, work, or cleaning 24 hours prior to your exam.
  • Do not bring children or pregnant women with you to the exam.
  • If you have diabetes, do not eat for two hours prior to the exam and do not take insulin within four hours of your exam. If you have a blood glucose level of greater than 200 mg/dL, your exam may need to be rescheduled. Consult with your physician with questions or concerns.

To schedule a PET/CT scan, please contact us at (716) 836-4646.

Contact Us

If you have additional questions about the test or the radiation involved, please visit

PET (Positron Emission Tomography)

See more of Great Lakes Medical Imaging

Did you know we're on instagram? Connect with us @glmirad!

We offer our patients convenient, accessible care with multiple locations throughout Western New York.