A PET (Positron Emission Tomography) scan is a serious medical examination used to detect damage or abnormalities in the body systems by way of a radioactive agent called a tracer. The procedure is practically painless and helpful in determining illness. Take a few steps before your PET scan to help ensure accurate results and a comfortable experience.

Refrain from eating or drinking starting eight hours before the test.

Do not take any medications, unless the physician administering the test allows it.

Do not smoke or consume anything containing caffeine (even "decaffeinated" products, which still have small amounts of caffeine) for a full day before the test.

Inform your doctor if you are pregnant, breastfeeding or are claustrophobic (fear of enclosed spaced).

Drink plenty of water, between 16 and 48 ounces, before the test.


  • Different sources will yield different information about how to prepare for this test. Some say don't eat anything six hours before the test rather than eight. Some say medication can be taken before the test, just in smaller amounts. It may be better to err on the side of caution and forgo any prohibited activities for whichever time is longest.

    If you are a diabetic who takes insulin, ask your physician how much you should take before the exam.

    Sometimes, the exam rooms are unusually cold, so you may want to dress warmly.


  • Although the PET scan is virtually harmless and is not painful, you may be asked to sign a consent form before the procedure. Make sure to discuss your concerns with your doctor. The dose of radioactive material given is in no way toxic, but some patients may experience discomfort or minor medical complications, such as small tissue damage.