Why Can’t I Eat Before My PET Scan? - Cincinnati Children's Blog (2023)

FAQs

Why can't I eat before my PET scan? ›

The PET scan helps to detect the signs of high glucose consumption by cells. Therefore, having food before a PET scan is not recommended as it tends to throw your body's glucose levels out of balance and provide inaccurate results.

The radioisotope that is used in PET imaging, fluorine 18 fluorodeoxyglucose or 18F-FDG, is a glucose transporter. This radioisotope will go to any metabolically active areas in the body. If the glucose levels are elevated from food or drink the patient consumed prior to the test, the level of insulin will increase.

Why is it important to follow a low carb diet for 12 hours and fast before my PET/CT scan? To get the best results your blood sugar needs to be low so your cells will properly absorb the radioactive sugar.

Do not eat or drink anything, except water, for 6 hours before the exam. You may drink water, as much water as you can would be helpful, until arrival. Routine medications may be taken, unless you have been instructed otherwise.

PET appointment. You should have nothing to eat or drink except water for at least 4 hours before your appointment time. This includes chewing gum, hard candy, breath mints and tobacco products. should not be taken on an empty stomach can be taken with water and 1 or 2 saltine crackers.

We prefer that you avoid anything with caffeine (coffee, tea, chocolate, or soda) within 24 hours of the test. Caffeine alters the distribution of the radiopharmaceutical throughout your body, specifically to your heart.

Recommended foods:

Eggs, cheese, cottage cheese and nuts. Vegetables: you may eat low-carbohydrate vegetables such as asparagus, cabbage, cauliflower, celery, chilies, cucumbers, green or wax beans, green peppers, lettuce, mushrooms, olives, onion, tomatoes, summer squash, spinach and turnips.

Follow a special diet for 12 to 24 hours before the scan. Don't drink or eat anything, except water, for 6 hours before the scan.

Can I brush my teeth before a PET/CT scan? Normal brushing without swallowing mouthwash or toothpaste within the four hour preparation timeframe will have no effect on the outcome of your PET/CT scan.

Avoid food and drinks that contain sugar or carbohydrates for at least 24 hours before your scan. This will help to make sure that your images are of the best quality and help prevent having to reschedule your scan because of a blood sugar that is too high.

Does sugar affect a PET scan? ›

Patients with diabetes mellitus (DM) can have altered sugar transport into cells, potentially affecting the results of 18-FDG PET scans.

A morning blood glucose level below 175 mg/dL is a safe range for your PET/CT FDG scan appointment. In the morning after your practice run, you may return to your normal routines of eating and taking medicine until the evening before your scan.

The Day Before Your PET/CT Scan

It is important that you stay well hydrated. Unless you are on fluid restriction, please drink at least eight glasses of plain water. The quality of your scan may be improved if you follow a high protein, low carbohydrate, low sugar diet during the 24 hours prior to your scan.

For an oncologic FDG-PET scan, fasting is required for patients to lower their blood sugar level so that FDG would not compete with glucose for its transporters for tumor uptake during the PET scan.

Protein: Non-breaded beef, chicken, turkey, fish, pork, lamb or ham (without honey), hot dogs, lunch meats, fish, shellfish or crab, peanut butter (1-2 servings total), most nuts or sunflower seeds (2 ounces total) and eggs. Dairy: Low-fat cottage cheese, light yogurt, sour cream or butter.

Do NOT eat anything; drink only water. Drinking water is encouraged to ensure hydration for best test results. Continue to take medications as prescribed.

We will provide a meal or snack for you. Beginning 24 hours before your test, follow this diet (which is a low carbohydrate diet.) Use the guideline below for menu ideas. Snacks: Celery and peanut butter, light yogurt or cottage cheese.

AFTER 5:00 PM THE DAY BEFORE YOUR TEST: Avoid foods with sugar & carbohydrates such as bread, potatoes, corn, pasta, noodles, cereal and rice. Avoid fruit, yogurt, fruit juices and soda.

Usually, you'll be advised not to eat anything for 6 hours beforehand, but you can drink water. You should also avoid strenuous exercise for 24 hours before your appointment.

How long does a PET scan take full body? ›

From start to finish, the procedure takes about two hours to complete and typically does not require an overnight hospital stay. When you arrive for your scan, you may be asked to: Change into a hospital gown.

Food that should be avoided Before PET Scan :

Fruits and Vegetables- All fruits, potatoes, corn, carrots, legumes (other beans), tomatoes, peas, squash, veggie burgers.

Specific protocols may vary, but generally a PET scan follows this process: You will be asked to remove any clothing, jewelry, or other objects that may interfere with the scan. If you are asked to remove clothing, you will be given a gown to wear.

If you're having a brain PET-CT, it is important to limit brain activity before your scan. Your nurse may tell you not to read or listen to music while you're waiting for your scan. Your care team will ask you to urinate (pee) just before your scan.

The major drawback to standard PET is that the images are of substantially lower resolution than, for example, those of CT and MRI, and PET is generally poor at delineating anatomic detail.

Though most cancers are picked up on PET CT, there are a few which do not. The most important of these would be cancer of stomach (signet cell type). In such cases performing this test would be waste. However, there are cancers which are very sensitively detected which include lymphoma, GIST, etc.

For Whole Body PET scans, do not eat or drink anything containing sugar or artificial sweeteners for 24 hours prior to the exam. This includes gum, mints, candies, or sodas of any type.

Aspirin or aspirin-containing compounds – Stop taking five days before your procedure. Plavix – Stop taking five days before your procedure. Coumadin (warfarin) – Please obtain a laboratory test (INR) before your procedure to determine the exact time to stop the medication.

How do you flush your body after a PET scan? ›

What happens after the PET scan? After your PET scan, a very small amount of radioactive sugar will remain in your body. So, be sure to drink plenty of water to help flush it out your system. You don't need to follow any special dietary restrictions or guidelines after your PET scan.

Scanning the whole body all at once

PET (positron emission tomography) is an extremely safe and powerful method for imaging inside the body, used to evaluate organs and other tissues for potential diseases, including cancer.

Then, the patient will be asked to lie on a table that passes slowly through the scanner. The scanner resembles a CT scanner, but has a much larger opening. Some people fall asleep during the scan.

Drinking water is encouraged to ensure hydration for best test results. Continue to take medications as prescribed. If you are diabetic, ask your doctor about diet and medication, including withholding insulin for 4 hours prior to the exam (with the exception of an insulin pump, which is permitted).

“Instructions to fast for several hours prior to administration of contrast media were considered essential, and this policy has traditionally been kept due to concerns about vomiting and its potential to cause aspiration,” Yoshito Tsushima, with Gunma University's Department of Diagnostic Radiology and Nuclear ...

You will be asked to remove any clothing, jewelry, or other objects that may interfere with the scan. If you are asked to remove clothing, you will be given a gown to wear. You will be asked to empty your bladder prior to the start of the procedure.

You should stay still and not talk while the scanner takes pictures of your body, which usually takes up to 30 minutes. The scan is completely painless, but you may feel uncomfortable lying still for this long. If you feel unwell at any point there is a buzzer you can press to alert the medical team.

We will provide a meal or snack for you. Beginning 24 hours before your test, follow this diet (which is a low carbohydrate diet.) Use the guideline below for menu ideas. Snacks: Celery and peanut butter, light yogurt or cottage cheese.

Eating and drinking prior to contrast-enhanced CT can be allowed and are not associated with an increased risk of aspiration pneumonitis.

Can you drink water or coffee before a CT scan? ›

For four hours prior to your exam, please do not eat solid foods. You may drink fluids such as water, juice, or black decaffeinated coffee or tea. Some CT scan exams, particularly abdominal CT scans, may require that you drink water or an oral contrast so we may better visualize structures within the abdominal area.

Food that should be avoided Before PET Scan :

Fruits and Vegetables- All fruits, potatoes, corn, carrots, legumes (other beans), tomatoes, peas, squash, veggie burgers.