PET scan: patient information

How to prepare for your PET/CT scan

If you need to reschedule or cancel the appointment then please call us at 416-480-4336. You will be with us for approximately 3 hours. The actual scan takes approximately 30 minutes.


FOR 24 hours Prior to your appointment:	EAT foods that are high in protein like beef, pork, lamb, poultry, fish (all varieties, unbreaded), shellfish, eggs, cheese, cottage cheese, broccoli, asparagus, cauliflower, zucchini, spinach, mushrooms AVOID foods that are high in carbohydrates and foods with sugars and artificial sweeteners, including cereals, breads, muffins, pasta, rice, barley, potatoes, beans, lentils, fruit Do not do any strenuous exercise.
For 5 hours prior to your appointment:	DO NOT EAT (including chewing gum or mints). You may only drink plain, unflavoured water to stay hydrated.
If you take insulin	For insulin diabetics, fast for 4 hours. Do not inject insulin within 3 hours of the test. Your sugar level must be below 11 mmol/L at your appointment time. If you experience symptoms (e.g. fast heart rate, headache) that suggest your blood sugar is low, take the appropriate measures as you normally would. Call us or inform the technologist on your arrival.
If you take other medication	All medications can be taken on your normal schedule
If you are claustrophobic	If you are claustrophobic, you may want to request a light sedative from your physician. You will need someone to drive you home if you take this medication.
Getting to my appointment	Your appointment is located at our Bayview Campus: 2075 Bayview Ave, Toronto, ON M4N 3M5. Check in at the Nuclear Medicine Department in the A-Wing, Ground Floor (between the Odette Cancer Centre and main hospital building). Bring your health card. Please wear clothing without metal (buttons, zippers) and do not bring jewelry.

How PET scans and Nuclear Medicine Work

PET (Positron Emission Tomography) scans are a type of Nuclear Medicine examination. Nuclear Medicine examinations are different from X-Rays. X-rays show what your body structure looks like. Nuclear Medicine examinations show how your body’s organs are actually working. First you swallow, inhale, or get injected with a substance called a radioactive tracer. This substance travels to the part of your body we want to examine. It gives off energy waves called gamma rays or positron emissions. A special camera builds these rays into pictures of your body indicating function or metabolic activity of different organs. The most common PET radioactive tracer is called FDG (Fludeoxyglucose). It is a substance like sugar.

What is a PET/CT SCAN?

PET scans are combined with a low dose CT (Computed Tomography) scan. The CT scan gives us detailed images of your anatomy or internal structures. This CT scan is used to enhance the PET image and help pinpoint the location of any abnormal tissue that may be seen on the PET scan. This low dose CT does not replace your regular CT scan. If your doctor has scheduled a CT scan for you in the CT department, you still need to do that.

For female patients

If you are breastfeeding or there is any chance that you are pregnant, tell the technologist before you have the injection. You may be required to have a pregnancy test prior to the injection.

What the scan is like

Be prepared to be here for 2 to 3 hours. You will be prepared for the test prior to the scan. The PET-CT scan itself takes approximately 30 minutes.
On your arrival we will measure your height, weight and measure your blood sugar level with a finger prick.
We will insert an IV line into a vein in your arm so that you are well hydrated and to provide an access to inject the radioactive sugar used for the scan. You should not experience side effects from the injection you receive.
You will rest in a dimly-lit room for up to 60 minutes to allow the radioactive sugar time to circulate through your body.
In the PET-CT suite, we will position you on the scanner bed on your back with your arms positioned above your head.
You will be in full view of the technologists through a TV monitor and through a glass window.
The bed will move through the scanner slowly to acquire images of your body. It is important that you remain still during the scan. You might hear buzzing or clicking noises from the scanner. These are normal and you don’t need to worry.

After your scan

You can eat and drink as you normally would (unless you are going on to have another test that has special restrictions).
Drink extra fluids for the remainder of the day to help flush the radioactive tracer from your body.