Also available in PDF format: Gastric Emptying Scan.pdf

What is a gastric emptying scan?

A gastric emptying scan (GES) is a nuclear medicine exam that uses a radioactive material eaten in a meal. This material allows doctors to see problems related to how your stomach empties. Diseases that change the way the stomach contracts (motility disorders) are best diagnosed by this test. It is a form of radiology, because radiation is used to take pictures of the body.

How does the scan work?

Pictures are taken over time of the movement of a radioactive meal through your stomach. The gamma camera detects the gamma rays emitting from the radioactive meal and then produces pictures and measurements of the stomach.

How should I prepare for the scan?

• You will need to fast for 6 hours before the test.
• If you smoke, do not smoke the morning of the test and during the hours of the test.
• It is best for females who are still menstruating to have the scan done in the first 10 days of their menstrual cycle.
• Patients should not take these drugs for at least 2 days before the test, unless told otherwise by their doctor:

      - Prokinetic agents: metoclopramide (Reglan), tegaserod (Zelnorm), erythromycin, and domperidone (Motilium)
      - Anticholinergic antispasmodic agents: Bentyl, Donnatal, Levsin, and Robinul
      - Opiate analgesics: Demerol, codeine, morphine, Oxycontin, Percodan, Percocet, Tylenol #3, Tylox, Fentanyl patch, Methadone

Note: Benzodiazepines such as Ativan, Valium, Librium, Xanax, and others, and phenothiazines such as Thorazine, Compazine, Phenergan, and others are OK to take. These drugs do not affect gastric emptying.

• All other medicines may be taken the day of the test with small sips of water. These should be taken at least 2 hours before the test begins.
• Do not take any laxatives the day before or any time during the test.
• If you have diabetes, your fasting blood glucose should be less than 275 mg/dL on the day of the test. A technologist will check your blood glucose before doing your GES test.
• Patients with diabetes should take half of their usual insulin dose when they eat the gastric-emptying meal at the clinic.
• If you have severe nausea on the day of your test, a medicine may be given to you to reduce your nausea. 

How is the scan performed?

• You will be given a fried egg and jam sandwich that has been injected with a small dose of radioactive material. You will be asked to eat the egg sandwich and drink water within 10 minutes. The egg will taste just like a regular egg. If you are allergic to eggs or wheat, Ensure (a liquid meal) will be used instead.
• After eating, you will be asked to lie flat on your back while the camera takes pictures of your stomach. You must not move when the camera is taking pictures. Moving will make the pictures blurry, and they may have to be taken again.

What will I feel during the scan?

• Lying still on the exam table may be hard for some patients. The technologist will help make you comfortable.
• From start to finish, your GES will take about 4 hours. There are 4 parts to the test:

     - First half hour: Eat meal and take 5 minutes for imaging
     - 1 hour after meal: 5 minutes for imaging
     - 2 hours after meal: 5 minutes for imaging
     - 4 hours after meal: 5 minutes for imaging

• After eating the meal, you are not allowed to eat or drink for the rest of the 4-hour period. You are also not allowed to exercise or exert yourself. 

Who interprets the results and how do I get them?

When the test is over, the nuclear medicine doctor will review your images, prepare a written report, and discuss the results with your doctor. Your doctor will then talk with you about the results and discuss your treatment options.