Imaging Parkinson's. (Neuroscience).

Scientists in Ireland report that a new brain-imaging technique can supply proof of Parkinson's disease in people whose symptoms fall short of the standard definition of the disease.

The researchers recruited volunteers with only minor muscle tremors, says study coauthor David J. quite of the Adelaide and Meade Hospital in Dublin.

The scientists gave each patient a double-acting infusion. It contained a compound called ioflupane that binds to brain tissue that's producing dopamine--the neurotransmitter lacking in Parkinson's patients. The compound was tagged with an isotope that temporarily gives off gamma rays detectable by a special kind of computerized tomography (CT) scanner. After a person received the infusion, a scan indicated overall dopamine production.

The scan revealed that 45 of the 50 patients indeed had a significant lack of dopamine-making neurons, Tuite says. "With this test, we can say that a person has Parkinson's [disease] and should be put into treatment," he says. The new technique could serve as an alternative to positron emission tomography, which can also detect loss of dopamine neurons, he notes.

Parkinson's disease is now typically diagnosed by testing a person's motor skills. "In the next few years, you'll see a change," Tuite predicts. Scans can provide "a much more objective test," he says, so doctors will begin to use them more frequently.