Miniature 'Wearable' Pet Scanner Ready For Use

Scientists from the U.S. Department of Energy's (DOE) Brookhaven National Laboratory, Stony Brook University, and collaborators have demonstrated the efficacy of a "wearable," portable PET scanner they've developed for rats. The device will give neuroscientists a new tool for simultaneously studying brain function and behavior in fully awake, moving animals. The researchers describe the tool and validation studies in the April 2011 issue of Nature Methods.

"Positron emission tomography (PET) is a powerful tool for studying the molecular processes that occur in the brain," said Paul Vaska, head of PET physics at Brookhaven with a joint appointment at Stony Brook, who led the development of the portable scanner together with Brookhaven colleagues David Schlyer and Craig Woody. PET studies in animals at Brookhaven and elsewhere have helped to uncover the molecular underpinnings of conditions such as drug addiction.

But studying animals with PET has required general anesthesia or other methods to immobilize the animals. "Immobilization and anesthesia make it impossible to simultaneously study neurochemistry and the animals' behavior - the actions resulting from what goes on in the brain," Schlyer said. "Our approach was to eliminate the need for restraint by developing a PET scanner that would move with the animal, thus opening up the possibility of directly correlating the imaging data with behavioral data acquired at the same time."

After several years of development, the scientists have arrived at a design for a miniature, portable, donut-shaped PET scanner that can be "worn" like a collar on a rat's head for simultaneous studies of brain function and behavior. Weighing only 250 grams, the device - dubbed RatCAP, for Rat Conscious Animal PET - is counterbalanced by a system of springs and motion stabilizers to allow the animal significant freedom of movement. Measurements of the rats' stress hormones indicated only moderate and temporary increases.