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PET (Positron Emission Tomography)

Location: 170 Elizabeth St., 2nd floor, Burton Wing.
Phone: 416-813-6065
Fax: 416-813-6043
Reception Hours: 7 a.m. to 4 p.m., Monday to Friday
Outpatient appointments: 8 a.m. to 3 p.m., Monday to Friday
There are no outpatient appointments on evenings, weekends, or statutory holidays. Please note, we do not offer walk-in appointments and no on-call hours.

Positron Emission Tomography (PET) is a type of medical imaging that helps doctors find and treat certain diseases. It uses a small amount of a radioactive medicine to look at how organs and tissues are functioning at the cellular level, allowing doctors to diagnose certain diseases earlier.

PET and CT scans

PET scans can be combined with another imaging technique called a CT scan. A CT scan uses X-rays to take detailed images of the body. Both scans use the same special camera to create 3D pictures of the body.

These pictures are helpful for doctors to gain information about how the body looks on the inside and understand how the body is working at the cellular level.  When done together a PET/CT scan is very good at showing the exact locations of specific diseases and correlating them with functional changes.   

These detailed pictures will give your child’s doctor more information about conditions such as paediatric tumors and neurological (brain) changes. 

Types of scans

Looks at changes at the molecular or cellular level within the body to help in the diagnosis, management and assessment of treatment response in certain types of cancers.

Looks at chemical and functional changes in the brain.  Doctors use this test to assess brain function and locate certain areas of the brain that may be functioning differently than usual, which can be important in cases of seizures or other neurological conditions.


Your child will be asked to fast (no food or drink) for at least 4 hours before the test. This includes no candy and gum. If your child needs to have general anesthesia for the pictures, separate instructions will be provided.

One parent or caregiver may stay with the child during the test. Only one parent can stay at any given time and may choose to leave after the child has been injected, especially with older patients. Siblings are not allowed in the room during the test. Eating and drinking is also not allowed in the room. Both scans is done in two parts with the Total Body PET scan taking 2.5 hours and the Brain PET scan taking 1.5 hours. 

For a Total Body PET scan, do not perform intense physical exercise at least 48 hours before the test. Routine playing and school activities are fine.


Medical staff preparing a child for a PET scan

Your child will need intravenous (IV) access for this procedure. An IV is a needle that is inserted into a vein in the arm or back of the hand. A small amount of blood will be taken to check your child’s sugar levels.

Next, a radioactive medicine will be injected through the IV. This medicine mixes with blood and takes approximately 45 minutes to be absorbed by the body or brain cells. Once the medicine is given, your child will be covered in warm blankets and will have to remain still and quiet for the 45 minutes.

Limiting movement and talking is very important for the medicine to reach important body parts. Your child should not feel any discomfort and can choose to watch a show or movie for distraction except for during the uptake portion of the PET Brain scan to avoid altering pharmaceutical uptake due to stimulation.

Your child will be asked to pee or have a diaper change before starting the second part of the test. They will then lie down on a narrow bed and a seat belt will go across their stomach to help them stay still while our special camera takes pictures.

For PET body scan

This will take approximately 30 minutes. The bed will slide in and out of a donut shaped machine. For a CT scan, a contrast material will be given through the IV that was previously placed during part one. A special, donut shaped camera will use X-rays to take pictures of the body's internal system. After the CT scan is complete, we will start the PET scan. It measures important body functions, such metabolism, helping doctors see how organs and tissues are functioning. Your child should not feel any discomfort during the PET scan.

For PET brain scan

The pictures will take about 10 minutes to complete. The bed will slide in and out of a donut shaped machine. This helps doctors observe chemical and functional changes within the brain and locate areas of the brain that may be causing seizures. Your child should not feel any discomfort during the PET scan.

It is important to give your child plenty of fluids for the rest of the day to keep them hydrated and help the medicine leave the body quicker.


The scan results are given by a doctor specialized in Nuclear Medicine and not by the technologist doing the test.  A report is sent to your doctor’s office, usually within 2-3 business days.

Please call the Nuclear Medicine Department at 416-813-6065 if you have any questions about the procedure or if you need to change the appointment.

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