What you can expect

The PET-CT or PET-MRI scanner is a large machine that looks a little like a giant doughnut standing upright, similar to CT or MRI scanners.

From start to finish, the procedure takes about two hours to complete and typically does not require an overnight hospital stay. When you arrive for your scan, you may be asked to:

• Change into a hospital gown
• Empty your bladder

A member of your health care team injects the radioactive drug (tracer) into a vein in your arm or hand. You may briefly feel a cold sensation moving up your arm. You rest and remain silent in a reclining chair for 30 to 60 minutes while the tracer is absorbed by your body.

During the procedure

When you are ready, you lie on a narrow, padded table that slides into the part of the scanner that looks like a doughnut hole. During the scan you must be very still so that the images aren't blurred. It takes about 30 minutes to complete a PET-CT scan and 45 minutes for a PET-MRI scan. 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 anxiety causing you discomfort. He or she may give you a drug to help you relax.

After the procedure

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.