Positron emission tomography (PET) scan is a nuclear medicine diagnostic test that shows the brain's use of oxygen or glucose (sugar). A very low, safe dose of a radioactive substance is injected into a vein in the arm, and the scanner records its circulation. The image shows areas of the brain that are more active than others. This test can help identify the area(s) of the brain where partial seizures begin or it can estimate plaque buildup in the brain.

A PET scan may be used to diagnose or rule out certain neurological conditions, including:

• Aphasia
• Concussions
• Cranial base tumors
• Dementia
• Epilepsy
• Facial nerve disorders
• Headaches
• Huntington disease
• Migraines
• Moyamoya disease
• Tic disorders