PET's ability to measure metabolism also has significant implications in diagnosing Alzheimer's disease, Parkinson's disease, epilepsy and other neurological conditions, because it can vividly illustrate areas where brain activity differs from the norm.
Alzheimer's Diagnosis: Until recently, autopsy has been considered the only definitive test for Alzheimer's disease (AD). Recent studies indicate that PET can supply important diagnostic information and confirm an Alzheimer's diagnosis. When comparing a normal brain versus an AD-affected brain on a PET scan, a distinctive image appears in the area of the AD-affected brain. This pattern is seen very early in the AD course. Conventionally, the confirmation of AD is a long process of elimination that averages between two and three years of diagnostic and cognitive testing. Early diagnosis can provide the patient access to therapies, which are more effective earlier in the disease.
PET also is useful in differentiating Alzheimer's disease from other forms of dementia disorders, such as vascular dementia, Parkinson's disease, Huntington's disease, etc.
Epilepsy: PET is one of the most accurate methods available to localize areas of the brain causing epileptic seizures and to determine if surgery is a treatment option.