What is a FDG PET/CT scan?

A PET/CT, which stands for Positron Emission Tomography/Computed Tomography, is a medical imaging technique that combines two types of scans to provide functional and structural information about your body.

PET/CT’s use a baseline measurement of sugar (called glucose) to help establish normal cell activity, with the increase and/or decrease in glucose being used as a measurement to help detect cancer, dementia, and epilepsy.

The PET/CT exam involves two components. The PET portion involves injecting a small amount of radioactive glucose (called FDG) through a vein in your arm. These elements circulate through your body emitting photons, which are used by the PET camera to measure cell activity. The second test component, the CT, uses X-rays to map your body’s internal structures, like bones and organs.

By combining the two images together, a PET/CT scan becomes a powerful imaging tool helping your care team pinpoint the location and nature of your potential disease which is tremendously helpful in your treatment plan.

What patients may see

Exam Process

Patients can expect to be onsite for a total of 2 hours with the following exam steps:

  • Untitled design - 2023-09-04T020807.103 Check-In/Paperwork
  • Untitled design - 2023-09-04T020807.103 Technologist Meeting
  • Untitled design - 2023-09-04T020807.103 Quiet Room (1-hour)
  • Untitled design - 2023-09-04T020807.103 Glucose Check and Injection
  • Untitled design - 2023-09-04T020807.103 PET/CT scan (15-50 minutes)

Preparation: FDG PET/CT Exam Do’s and Do Not’s

Patients can expect to be onsite for a total of 2 hours with the following exam steps:


DO Drink as much plain and unflavored water as you like; at least 3 glasses are recommended before you arrive.
DO Take other prescribed medications on the day of your appointment – unless otherwise instructed by your doctor.
DO Wear warm comfortable clothing such as sweats or a jogging suit with no metal if possible. Gowns are available if needed.
DO Remember to bring a picture ID and your insurance cards.
DO Allow 2 (to 3) hours for the procedure.


DO NOT Exercise 24 hours prior to your scan.
DO NOT Eat anything for six (6) hours before your appointment.
DO NOT Eat carbohydrates such as bread, rice, potatoes, or pasta with your last meal prior to 6-hour fasting period.
DO NOT Chew gum, breath mints, cough drops, cough syrup, coffee, or tea.
DO NOT Smoke e-cigarettes six (6) hours before your appointment.
DO NOT Drink any flavored or sweetened water such as Vitamin Water, Propel, etc.
DO NOT Bring children or pregnant women with you due to the risk of exposing them to radiation

Glucose Levels (Diabetic Prep)

Controlling blood sugar level is crucial for obtaining a clear and accurate PET scan. If you have high blood sugar levels over 200 mg/dL, please follow our diabetic preparation guide found on our website.

Wear Comfortable Clothing

NCPIC keeps the exam rooms cool (about 68 degrees) be sure to arrive in comfortable clothing without metal zippers, buttons, underwire garments, and bras for better image quality. Gowns are also available for patient use.

Anxiety Medication Preparation

If you need to take medication for pain or anxiety, please bring the medication with you. NCPIC also recommends having a driver escort you home as a safety precaution.

Post Scan Care & Results

Your referring doctor will get the exam results approximately 24 hours after the exam is performed. After your PET/CT exam is completed, you are safe to resume normal daily activities with the recommendation that you drink plenty of water to help flush the radiopharmaceutical out of your system.

Safety and Radioactivity

It is important to note that PET/CT exams use a small amount of radioactive material to achieve an image which is deemed safe. For more information on radiation exposure safety, please visit the NEA.