PET (positron emission tomography)

Positron emission tomography (PET) is a technique that monitors the chemical changes to produce detailed images of the brain. A radioactive tracer is used to enter the brain. The tracer will collect where the most brain activity is happening, which helps pinpoint the origin of seizures.

In recent years, PET and computed tomography (CT) scanners have been combined into one test. As CT scanners became faster and decreased in cost, PET/CT scanners, a combination camera capable of producing both anatomic and physiologic resolution simultaneously, were developed. This advance in the detail of information obtained by a PET/CT scanner has been shown to be much more accurate in evaluating patients than the information previously obtained by a separate PET-only or CT-only scan.

Similar to PET/CT, there is now PET/MRI. Although there can be an overlap with the information gained, each imaging technique has its optimal uses. PET/ MRI is ideal for imaging the nervous system, specifically the brain and spinal cord. It also significantly decreases the radiation exposure to a patient, estimated at up to a 40% reduction.

Texas Children’s Hospital was one of the first hospitals in the world, and the first free-standing children’s hospital in North America, to have both PET/MRI and PET/CT scanners. We are at the forefront of creating protocols for radiation reduction for our pediatric patients – and this is another step towards that standard.


Before a PET/CT Scan

A PET/CT scan is a non-invasive, safe and pain-free test. Before the test, your child will receive a small shot to dispense the tracer liquid. They may feel a tiny poke from the needle. Small stickers will be placed on your child’s head (similar to an EEG) to measure brain activity during the test.

After the shot, your child will be asked to rest up to one hour to ensure the tracer is fully distributed throughout the brain. During this time, they will be asked to stay as relaxed as possible. Texas Children’s child life specialists are available should your child need help with calming techniques.

During a PET/CT Scan

Your child’s PET/CT scan will last approximately 30 minutes to one hour. As the test begins, they will lay on a flat examination table that slides into a round, vertical circle. The test is painless, and the machine will not touch your child. They will be asked to stay very still during the test. As a parent or guardian, you able to remain in the room with your child during the scan. You are encouraged to hold your child’s hand and speak with them to help them remain calm throughout the test.

After a PET/CT Scan

Your child will not experience any downtime. After the test concludes, your child may resume regular activities and diet.