Mohammed Ali and Michael J. Fox are just two of the more than one million people, both men and women, in the United States who suffer from Parkinson's disease (PD). The symptoms are progressive and by now familiar to most of us: the frozen face that is part of the rigid body posture, the tremor that is often uncontrollable, the difficulty with walking and the instability of posture. PD was first described in 1817 by an English physician, Dr. James Parkinson, who called it "Shaking Palsy." It wasn't until the 1960's that pathological and biochemical brain changes were identified as the cause, specifically the degeneration of the brain areas that produce dopamine. Administration of the drug leveodopa, which is converted by the brain into levodopa, has been the standard treatment for PD. A common problem has been how to get a high enough concentration of the drug to reach the brain without causing side effects. Other drugs have been developed to enhance this process.
		PET can definitively diagnose Parkinson's disease. Research using PET has been responsible for many of the discoveries about how the disease affects the brain. PET is being used by researchers searching for a cure.