Proposed Standard Patient Preparation Protocol for 18F-FDG PET and PET/CT

Dietary Instructions
• Complete food fasting is required, including cessation of tube feedings, dextrose-containing intravenous fluids, and parenteral hyperalimentation (minimum of 6 h before scan).
• Only plain water is permitted; flavored water is not allowed (6 h before scan).
• Absolutely no sugar or carbohydrate intake of any kind is allowed, including candy or breath mints (6 h before scan).
• No caffeine, alcohol, and nicotine products are allowed (12 h before scan).
• A high-protein, low-carbohydrate diet is required (24 h before scan).
Sample menu:
 Main course: Beef, turkey, pork including bacon, fish, chicken, eggs.
 Vegetables: Broccoli, asparagus, cauliflower, zucchini, spinach, mushrooms.
 Desserts: Cheese, cottage cheese.
 Drinks: Unsweetened black coffee, unsweetened tea, water. Artificial sweeteners are not permitted.
 Carbohydrates/sugars to be avoided: Bread, bagels, cereal, cookies, toast, pasta, crackers, muffins, peanut butter, nuts, fruit, fruit juice, potatoes, candy, rice, cornbread, carrots, beets, chewing gum, mints, cough drops, and sweet soft drinks.
• Patients are encouraged to stay well hydrated. Recommend 2 L of plain drinking water in the 4-h period immediately before PET/CT. Continued hydration as tolerated is recommended after scan completion to enhance 18F-FDG excretion.
Activity Restriction (Minimum 24 h Before Study, Although 48 h Is Ideal)
• Exercises such as jogging, cycling, weightlifting, strenuous housework, yard work, and sexual activity should be avoided.
• Patients are advised not to chew gum.
• All prescription medications should be taken as directed (insulin and oral hypoglycemics are discussed under “Diabetic Patients”).
Diabetic Patients
• Home blood glucose checks should be performed in the days leading to the PET exam to ensure adequate blood glucose levels (≤200 mg/dL).
• All prescription oral diabetes medications should be taken as directed.
• Metformin may be discontinued for 2 days before the study if there are gastrointestinal tumors (to minimize inadvertent gastrointestinal uptake) or if there has been prominent gastrointestinal uptake on prior PET studies.
• Patients on regular insulin should take their normal amount of insulin along with breakfast by 6 am. They should be scheduled between 12 noon and 1 pm. Alternatively, those receiving evening or bed-time long-acting insulin should be scheduled at 7 am after an overnight fast.
• Patients on continuous insulin infusion/pump are scheduled early in the morning (by 8 am) and eat breakfast after the PET study. The insulin pump is kept on the night/basal setting until after the PET study.
Strategies for addressing hyperglycemia (>200 mg/dL) immediately before 18F-FDG PET study:
• Reschedule scan, encourage frequent home blood glucose checks, and ask patient to contact primary care physician for further guidance on glycemic control (OR)
• Start regimen of intravenous short-acting regular insulin. (Implementation requires staff with extensive training on use of intravenous insulin, frequent blood sugar monitoring, and identification and correction of potential hypoglycemia.)
  2 units for blood sugar between 201 and 250 mg/dL.
  3 units for blood sugar between 251 and 300 mg/dL.
  4 units for blood sugar between 301 and 350 mg/dL.
  5 units for blood sugar between 351 and 400 mg/dL.
Target blood sugar is ≤200 mg/dL.
18F-FDG is injected at least 60 min (ideally 90 min) after insulin administration.
Premedication (as Needed)
• For patients with head and neck cancer, claustrophobia, anxiety, or a need to relax skeletal muscles: Oral alprazolam, 0.5 mg, at the time of 18F-FDG injection. (Patients should be warned against driving because of sedating effects and psychomotor impairment.)
• For patients with prominent brown adipose tissue uptake: Oral β-blocker propranolol, 20 mg, 1 h before 18F-FDG injection. (Heart rate and blood pressure monitoring must be performed while the patient is in the PET clinic.)
Environmental Conditions
• Patients should avoid cold exposure for 2 d before the study.
• Patients should avoid air conditioning on the day of the study.
• Patients should keep the car windows rolled up during travel to the PET/CT clinic and, if necessary, use a car heater on cool days.
• Patients should wear warm clothing, including long pants or slacks, long sleeves in summer (no shorts or tank tops), and a sweater, jacket, and cap on cold or even slightly cool days.
• Maintain a warm room temperature (minimum, 75°F), and provide warm blankets during the uptake period.