What you can expect

By Mayo Clinic Staff

The PET scanner is a large machine that looks a little like a giant doughnut standing upright, similar to a computerized tomography (CT) machine. You'll need about two hours for the procedure, which may be done on an outpatient basis (no overnight hospital stay). When you arrive for your scan, you may be asked to:

  • Change into a hospital gown
  • Empty your bladder

Then you will be given a radioactive drug (tracer). You may receive the drug by injection or be asked to inhale or swallow it, depending on the type of tracer being used. If the drug is injected, you may briefly feel a cold sensation moving up your arm. You'll need to wait 30 to 60 minutes for the tracer to be absorbed by your body.

During the PET scan

When you are ready, you'll lie on a narrow, padded table that slides into the scanner. During the scan you'll need to lie very still so that the images aren't blurred. It takes about 30 minutes to complete the test. The machine makes buzzing and clicking sounds.

The test is painless. If you're afraid of enclosed spaces, you may feel some anxiety while in the scanner. Be sure to tell the nurse or technologist about any discomfort. He or she may give you a drug to help you relax.

In some cases you may have a CT and PET scan in the same machine during the same appointment. The CT scan will be done first and take about 10 minutes.

After the PET scan

After the test you can carry on with your day as usual, unless your doctor tells you otherwise. You'll need to drink plenty of fluids to help flush the tracer from your body.

May. 06, 2014