Preparing for Your PET/CT Scan (FDG)
48 Hours Before Your Scan
- Avoid strenuous activity: jogging, cycling, weightlifting, or heavy physical work.
24 Hours Before Your Scan
- Follow a high-protein, low-carbohydrate diet. Avoid bread, pasta, rice, potatoes, cereal, and sugary foods.
- No gum chewing.
12 Hours Before Your Scan
- Avoid alcohol, caffeine, and nicotine.
4–6 Hours Before Your Scan
- Stop eating. Water only from this point on — no sugar, gum, candy, or breath mints.
- Morning appointments: Stop eating after midnight. A light meal the evening before is fine.
- Afternoon appointments: You may have a light meal before 8:00 AM, then fast until your scan.
2 Hours Before Your Scan
- Drink 2–3 glasses of water (about 12 oz. each).
After Your Injection
- Drink 2–3 more glasses of water.
Medications
- Take all your regular medications as prescribed unless told otherwise.
- Do not stop any medication before your exam without talking to your doctor first.
If You Have Diabetes
- Check your blood sugar at home in the days before your appointment. It should generally be under 200 mg/dL.
- Take your regular oral diabetes medication (such as metformin) as prescribed.
- If you take morning short-acting insulin: take it with breakfast by 6:00 AM. Your appointment will be scheduled between 12:00–1:00 PM.
- If you take long-acting insulin at night: you can be scheduled early in the morning after an overnight fast.
- If you use an insulin pump: your appointment will be scheduled early in the morning. Keep your pump on its overnight/basal setting, and plan to eat breakfast after your scan.
- If your blood sugar is above 200 mg/dL when you arrive, we may need to reschedule your appointment. Please contact your doctor and monitor your blood sugar closely before your new appointment date.
Staying Warm
- Please wear warm clothing to your appointment. We'll also provide a blanket during your wait time before the scan — staying warm helps improve image quality.
Questions?
Please call us at 847-616-2000 if you have any questions about your preparation instructions.