Your doctor has recommended that you have a PET/MRI (positron emission tomography/magnetic resonance imaging) scan. PET/MRI combines the functional imaging of PET with the anatomic imaging of MRI for exceptional image quality. PET/MRI is used to analyze a variety of cancers, as well as various neurological and cardiac conditions. Our team of specialized doctors, nurses and technologists is led by Louise Thomson, MD and Alessandro D'Agnolo, MD, co-chiefs of Nuclear Medicine.

Before Your Exam

  • It is very important to follow all preparation instructions below to ensure the best image quality.
  • If you are diabetic or have cardiac sarcoidosis, please call 310-423-8738 to discuss important information about diet and medication.
  • If you have any of the following, please call your doctor to discuss whether you should proceed with the exam: any metal implants, claustrophobia or pain when lying in a scanner, are pregnant or may be pregnant.
  • If your doctor gave you an order, please bring it with you.
  • If you have any questions, please call Nuclear Medicine at 310-423-8738.

48 Hours Before Your Exam

  • Refrain from all strenuous exercise or deep-tissue massage.

24 Hours Before Your Exam

  • Strictly follow the low-carbohydrate, no-sugar diet below.
  • Hydrate by drinking plenty of water, unless restricted.
  • If you are having a brain PET scan, avoid foods and beverages with caffeine (including decaffeinated drinks).

Day of Your Exam

  • Starting six hours before your scan, it is very important that you do not eat, drink (except water) or chew gum or mints (including sugar-free). Continue to stay hydrated by drinking water.
  • Continue taking any regular prescribed medications unless instructed not to do so.
  • Wear warm, comfortable, loose-fitting clothing with minimal metal and avoid wearing jewelry.
  • Bring a list of your current medications with you.

During Your Exam

  • Please be sure to arrive at your specified check-in time, as this exam uses time-sensitive procedures and may need to be rescheduled if you do not arrive on time. We recommend giving yourself enough time (about 20 to 30 minutes) to park and walk to the S. Mark Taper Foundation Imaging Center.
  • The duration of your exam will vary, but  please plan to be at the imaging center for about three hours. Due to the nature of the exam, children and pregnant women are not allowed to accompany patients in the exam or waiting areas.
  • You will be transported to the nearby PET/MRI imaging facility for your exam.
  • An IV line will be placed to administer the radioactive glucose (FDG) and will remain in place until the scan is completed. Commonly, contrast is injected to better define the images of the body. If your MRI requires contrast, it will be given through the same IV that was placed for the FDG.
  • The FDG will be given and must circulate for about 60 to 90 minutes before your scan can begin. You will be asked to sit quietly in the waiting room during this time.
  • The technologist will position you on the scanner table, and give you instructions to remain still or to hold our breath. You can ask the technologist questions before the exam begins.

After Your Exam

  • After the exam, you will be able to drive yourself home.
  • Please drink plenty of fluids (about five glasses of water) throughout the day to help rinse the FDG and any contrast from your system.
  • Your PET/MRI will be interpreted by an expert imaging physician, and a report will be sent to your doctor. Please contact your primary care physician for the results.

PET/MRI Preparation Diet

Starting 24 hours before your scan, follow a low-carbohydrate diet. Additionally for PET brain patients, refrain from having any foods and drinks with caffeine.

Starting six hours before your scan, begin fasting by avoiding all food, drink (except water) and all gum/mints.

Suggested Foods

  • Protein: Nonbreaded beef, chicken, turkey, fish, pork, lamb, ham (without honey), hot dogs, lunch meats, fish, shellfish, crab, peanut butter (one or two servings total), most nuts and sunflower seeds (2 ounces total) and eggs
  • Dairy: Low-fat cottage cheese, cheese, sour cream, butter, half-and-half
  • Vegetables: Green beans, asparagus, broccoli, cabbage, cauliflower, celery, cucumber, lettuce, mushrooms, radishes, spinach and zucchini
  • Condiments: Mayonnaise, salad dressing (those with 3g or less per serving of carbohydrates), oil, vinegar, mustard, hot sauce, tartar sauce, olives, dill pickles
  • Beverages: Diet soda, black coffee or tea (may add artificial sweetener and half-and-half, water (diet flavored OK), sugar-free Crystal Light

Foods to Avoid

All foods containing sugar and most processed foods, even “low-carb” items.

  • Potatoes
  • Corn
  • Carrots
  • Legumes
  • Squash
  • Ketchup
  • CerealTomatoes
  • Peas
  • Fruit
  • Juices
  • Milk
  • Chips/pretzels
  • Yogurt
  • Bread — all types of grains
  • Breaded foods
  • Rice (white and brown)
  • Pastas/noodles
  • Sauces and gravy
  • Candy/gum (including sugarless)
  • Nutritional shakesVeggie burger
  • Soybeans and tofu
  • Syrups and jams
  • Crackers
  • Breath mints
  • Rice cakes
  • Smoothies

Caffeinated Foods to Avoid (only for patients having PET brain)

Starting 24 hours before your scan, avoid all foods containing caffeine, including decaffeinated beverages.

Common examples include:

  • Coffee
  • Decaf coffee/tea
  • Chocolate
  • Candy bars
  • Hot chocolate
  • Some protein bars (check label)
  • Some noncola sodas (check label)
  • Some ice creams and yogurt (check label)
  • Some fancy waters (check label)