Positron Emission Tomography (PET)

PET is a neuroimaging scan that measures how intensely different parts of the brain use glucose, oxygen, and other substances. Areas of decreased usage may indicate a site where a seizure begins and therefore a possible place for surgery.

A small amount of radioactive substance will be inhaled (breathed in) or injected into your child's bloodstream. The brain is then scanned to see how and where the substance is absorbed. This procedure is similar to a SPECT scan.

What happens before the PET

Special preparation is required for this scan. Your child should not eat or drink anything for six hours prior to the scan. Comfortable and warm clothing is recommended.

In Canada, the availability of PET remains quite limited because of  government regulations. It is because of these strict regulations that Canadian patients are required to sign a research consent form before they can have a PET scan. We continue to collect data on children who have had a PET scan to provide evidence that in selected cases of children with severe epilepsy, PET has a role in the investigation of severe epilepsy, especially as part of epilepsy surgery.

What happens during the PET

At the beginning of the procedure, your child will be given a small amount of radioactive substance, either by injection or inhalation. The child can then rest for about 45 minutes while the substance travels to the brain.

Your child will then lie down on a table with his head in a special headrest which will prevent his head from moving. Your child will need to keep still while the table passes slowly through the scanner. Your child's head will be inside the large hole in the machine while the scanner is taking the images. The whole procedure takes about two hours.

There should be no after-effects from the injection or the scanning.

Your child may also have an EEG at the same time as the PET.

What happens after the PET

The results of the PET test will be analyzed by your child's treatment team. They will be used with the results from other tests to decide on the best treatment or surgery for your child.

Elizabeth J. Donner, MD, FRCPC

Nicole E. Brown

Elysa Widjaja, MBBS, MRCP, FRCR, MD

Maria Green M.R.T.(N.)