Skip to content
My WebMD Sign In, Sign Up

Information and Resources

Font Size

Positron Emission Tomography (PET)

How To Prepare continued...

Do not smoke or drink caffeine or alcohol for 24 hours before this test.

Do not eat or drink for at least 6 hours before this test.

Tell your doctor if you are or might be pregnant or if you are breast-feeding. If you are breast-feeding, you will need to use formula for 1 to 2 days after the PET scan so you won't pass the tracer to your baby. This generally takes 24 hours.

Tell your doctor if you have a fear of enclosed spaces or have ever had a panic attack.

You may be asked to sign a consent form.

Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done or what the results mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).

How It Is Done

A positron emission tomography (PET) scan is done in a hospital nuclear medicine department or at a special PET center by a radiologist or nuclear medicine specialist and a technologist. You will be asked to lie on a table that is hooked to a large scanner, camera, and computer.

During the test

The radioactive tracer is usually given in a vein (IV). You may need to wait 30 to 60 minutes for the tracer to move through your body. During this time, you may need to avoid moving and talking.

The PET scanner, which is shaped like a doughnut, moves around you. The scanned pictures are sent to a computer screen so your doctor can see them. Many scans are done to make a series of pictures. It is very important to lie still while each scan is being done. At some medical centers, a CT scan will be done at the same time.

For a PET scan of the brain, you will lie on a bed. You may be asked to read, name letters, or tell a story, depending on whether speech, reasoning, or memory is being tested. During the scan, you may be given earplugs and a blindfold (if you do not need to read during the test) to wear for your comfort.

If you are having a PET scan of your heart, electrodes for an electrocardiogram (EKG, ECG) will be put on your body.

During the test, you will be alone in the scanner room. The technologist will watch you through a window and you will be able talk to him or her through a two-way intercom at all times.

The test takes 1 to 3 hours.

After the test

After the test, drink lots of fluids for the next 24 hours to help flush the tracer out of your body.

WebMD Medical Reference from Healthwise

Last Updated: July 28, 2011
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

Hot Topics

WebMD Video: Now Playing

Click here to wach video: Dirty Truth About Hand Washing

Which sex is the worst about washing up? Why is it so important? We’ve got the dirty truth on how and when to wash your hands.

Click here to watch video: Dirty Truth About Hand Washing

Popular Slideshows & Tools on WebMD

feet
Solutions for 19 types.
highlighted areas of the brain
How well do you know yours?
oatmeal and eggs
The best and worst for you.
dog begging at table
Foods your dog should never eat.
MS Overview
Recognizing symptoms.
mature woman with serious expression
What do you know?
chlamydia
Pictures and facts.
Healthy Snack
13 delicious options.
Take your medication
Separate fact from fiction.
lone star tick
How to identify that bite.
young woman in sun
What to watch for.
woman clutching at stomach
Do you know what's causing yours?

Women's Health Newsletter

Find out what women really need.