PET Scans

A positron emission tomography (PET) scan is used to look at organs such as the heart and brain. It can also look at body tissues like lymph nodes.

PET scans show how your organs or tissues function chemically. This helps your doctor diagnose problems and make a treatment plan for you.

Example of PET scan

Preparing for a PET Scan

It is important to prepare for your PET scan. If you don't follow the instructions carefully, the test may not be accurate and you may need to repeat the scan. It is also likely your scan will need to be rescheduled.

You should not:

  • eat, drink (plain water is ok), chew gum or use mints at least 6 hours before the scan.
  • do any intense physical activities 24 hours before your scan

You should wear comfortable clothing.

If you are having a cardiac PET scan or are diabetic, there may be additional instructions for you to follow. Speak to your healthcare provider before your test to confirm how you need to prepare for your exam. 

Arriving for Your Appointment

You will need to arrive at least 30 minutes before your appointment time to check in and complete paperwork. If you have copies of previous scans that were done at an outside facility, bring them with you.

What Will Happen During My PET Scan?

First, you will have an IV (intravenous line) inserted into your arm. This will deliver a safe radioactive substance (tracer) into your vein.

While your body absorbs the tracer, you will rest in a reclining chair for about one hour.

Once the tracer is absorbed, the scan can be done. You must lie still on the cushioned table for 30 to 45 minutes. The table will slide into a large tunnel-shaped scanner. Only move when  you are asked to do so. If you are claustrophobic (afraid of enclosed spaces), tell your doctor or nurse -- if possible, before you arrive for your PET scan. You may be given a sedative to help you relax. Only move when you are asked to do so. 

Most scans take 1½ to 2 hours. You should plan for your entire visit to be at least 2½ hours. In some cases, it may take longer. 

What Happens After the Procedure?

If you were given a sedative, you must have a friend or family member available to drive you home and care for you for the next 24 hours.

Over the next 24 hours after your PET scan, drink plenty of clear fluids to help flush the radioactive material out of your body.

Patient Education (PDFs): PET Scan