How you prepare

By Mayo Clinic Staff

A PET scan is usually done on an outpatient basis. Your doctor will give you detailed instructions on how to prepare for your scan. Before undergoing the scan, be sure to tell your doctor about any prescription and over-the-counter medications you're taking, as well as any vitamins and herbal supplements. If you're taking certain medications or have certain diseases, such as diabetes, you'll receive specific instructions before your scan.

A general rule is to not eat anything for several hours before the scan. Wear comfortable clothes to your appointment. You may be asked to change into a hospital gown for the test. If an area of your body near your bladder needs to be examined, a soft tube (catheter) may be inserted into your urethra to keep urine drained from your bladder during the scan.

If you're pregnant or think you might be pregnant, tell your doctor before undergoing a PET scan. The radioactive substance used during this procedure may expose the fetus to radiation.

May. 07, 2011