FDG PET/CT Scan and Diabetes

Examination Instructions

Arrival time for appointment

Please arrive 30 minutes prior to your scan time. Late arrivals may result in rescheduling of your scan to a later date. Patients that do not show or cancel less than 24 hours prior to their appointment may be charged.

Appointment Instructions

To ensure the safety of our patients and staff, only the patient will be allowed into the scan area. Anyone that accompanies the patient will be limited to the waiting area and may be allowed in patient areas at the sole discretion of the staff

The day before your PET scan

  • Avoid strenuous exercise within 24 hours of your appointment.
  • Eat a high protein/low carbohydrate diet. Some examples of foods you may eat include
    • Eggs (any style) • Meat (beef, pork, chicken, fish, bacon, sausage) • Non starchy vegetables such as broccoli, cauliflower, green beans, lettuce • Cheese • Black coffee, sugar free teas • Diet soda • Water
  • Avoid eating carbohydrates such as fruit, milk, pasta, cereal, bread, rice, and starchy vegetables (examples: peas, potatoes, corn, chili beans).
  • Test blood sugars before each meal, bedtime, 3 a.m. and first thing the next morning.
  • If you use a sliding scale or correction factor and your 3 a.m. blood sugar is above 200, correct blood sugar as instructed. No additional insulin can be given after 3 a.m.
  • Do not eat anything after midnight. You may drink water.

On the day of your PET scan

  • Blood sugar level must be below 200 mg/dl in order to perform the exam.
  • Check your blood sugar after the overnight fast to make sure it is under 200.
  • Do not eat or drink fluids, except water for 6 hours prior to the test.
  • You may take your regularly scheduled non-diabetes medications if tolerated on an empty stomach.

Diabetes Medications

Okay to take on the day of

  • Continue usual Lantus, Toujeo, Tresiba or Levemir insulin dose.
  • Continue usual basal insulin if you wear an insulin pump. DO NOT give any boluses.

DO NOT take on the day of until AFTER your scan

  • Sulfonylureas: Glimepiride, Glipizide, Glipizide ER/XL,  Glucotrol, Glucotrol XL, Glyburide
  • SGLT-2 Inhibitors:  Farxiga, Invokana, Jardiance, Steglatro
  • Meglitinides: Prandin, Starlix
  • Metformin /Metformin ER
  • Actos/pioglitazone
  • DPP-4 Inhibitors: Alogliptin, Januvia, Nesina, Onglyza, Trajenta
  • GLP-1 Agonists: Bydureon, Byetta, Trulicity, Victoza, Ozempic ,Rybelsus
  • Combinations:   of any of the above medications
  • Meal-time Insulins: Apidra, Humalog, Humulin. Novolin R, NovoLog
  • Insulin NPH, U500, and Combinations: NPH (N), 70/30, 75/25, 50/50, U500
  • Call your diabetes provider if you have questions.

After the PET scan

  • You may resume all diabetes medications and normal activity.
  • Drink plenty of water to expedite the FDG leaving your body.