A positron emission tomography (PET) scan is a painless imaging test that helps visualize how various organs are working. It requires the injection of a small amount of radioactive tracer material into a vein, which is circulated through the body over the course of about one hour. After that time, the patient lies flat on a special table that fits into a circular scanning device. The scanner can create three-dimensional views of organs such as the lungs, heart and brain, or of breast and other tissues. PET imaging can be especially helpful in evaluating patients with epileptic seizures, as it allows epileptologists to actually see chemical changes that are taking place in the brain and how blood sugar is circulating within the brain cells. The scanning part of the PET test can take about an hour, and patients may be given medicine that helps them to remain still for that amount of time if needed.