PET/CT Scan

If you had chemotherapy or radiation treatment recently, let your doctor know the date of your last treatment. This will let them know the best time to schedule your PET scan.

The best time to have a PET scan is 3 weeks after your chemotherapy treatment or up to 6 weeks after your radiation treatment.

Bring with you to your appointment your:

• Your requisition (unless your doctor's office has already faxed us a copy or has entered an online request – possible for UHN physicians only)
• Government-issued health card (OHIP card)
• Latest CT imaging on a disk (if possible)
• A list of current medications that you are taking

Please arrive 15 minutes before your appointment so that we can process your paperwork. If you are late, your appointment may be subject to re-scheduling.

It is important to tell your technologist if you are breastfeeding or if there is any chance that you are pregnant. Tell the technologist before they inject you.

For patients without diabetes

• For 3 days before your scan, do not exercise hard. For example, you can go for a walk but do not run.
• For 6 hours before your scan, do not eat anything, including candies or gum. You can drink water.

Can I take medicine 6 hours before my scan?

• Do not take medicine that has sugar in it
• Do not take medicine you need to take with food
• Keep taking all other medicines

For patients with diabetes

For this scan to work, your blood sugar level has to be less than 10 mmol/L. If possible, it should be below 8.3 mmol/L. Check your blood sugar level often.

What if I can't get my blood sugar below 10?

If you cannot get your blood sugar level below 10, please call 416 946 4501 x 3172 to reschedule your appointment.

How to prepare

• For 3 days before your scan, do not exercise hard. For example, you can go for a walk, but do not run.
• On the day of your scan,
  If you take insulin, metformin, glyburide, Glucophage,  Diamicron or any other medication for your diabetes:
  • Take your medication 4 or more hours before your test
  • Have a light breakfast that is high in protein and low in carbohydrates with your medicine. For example, you can have a hard-boiled egg or bacon with coffee or tea.
  • Do not put sugar, milk or cream in your coffee or tea
  • Do not have toast, fruit or juice
  If you use diet to control your diabetes and do not take any diabetes medicines:
  • Do not eat anything for 6 hours before your scan, including candies or gum. You can drink water.

Can I take other kinds of medicine?

• Do not take medicine that has sugar in it
• Do not take medicine you need to take with food
• Keep taking all other medicines.

• When you arrive, the technologist will explain the test to you
• The technologist will inject a radioactive sugar called FDG into your arm or hand with a small needle
• You will wait in a special waiting area for 45 to 90 minutes. This gives the FDG time to get into the cells in your body.
• You will then go into the scanning room and lie down on a special bed
• The bed moves in and out of the scanner. You need to lie still and follow the instructions the technologist gives you. The scan can take about 30 to 45 minutes.
• When the scan is happening, the technologist will leave the room. They can still see you through a window and hear you through an intercom. You may hear buzzing or clicking noises from the scanner. These sounds are normal.

Once the imaging is complete, a Molecular Imaging Radiologist will review the images obtained and provide your doctor with a written report.

Please keep in mind the technologist cannot give you the results when your scan is finished.

If you need to cancel or reschedule your appointment, please call 416 946 4501 ext. 3172 the day before your scan appointment.

If you have any questions or concerns about your scan, please call 416 946 4501 ext. 3172.

You will be in the medical imaging department for 2 to 2½ hours. It takes some time to prepare for the scan.

The scan takes about 30 minutes. It may take another 15 minutes if the technologist needs to take extra pictures.​