Patients undergoing a positron emission tomography (PET) scan in today’s bulky, donut-shaped machines must lie completely still. Because of this, scientists cannot use the scanners to unearth links between movement and brain activity. What goes on up there when we nod in agreement or shake hands? How are the brains of people struggling to walk after a stroke different from those who can?
To tackle questions like these, Julie Brefczynski-Lewis, a neuroscientist at West Virginia University (WVU), has partnered with Stan Majewski, a physicist at WVU and now at the University of Virginia, to develop a miniaturized PET brain scanner. The scanner can be “worn” like a helmet, allowing research subjects to stand and make movements as the device scans. This Ambulatory Microdose Positron Emission Tomography (AMPET) scanner could launch new psychological and clinical studies on how the brain functions when affected by diseases from epilepsy to addiction, and during ordinary and dysfunctional social interactions.
“There are so many possibilities,” said Brefczynski-Lewis, “Scientists could use AMPET to study Alzheimer’s or traumatic brain injuries, or even our sense of balance. We want to push the limits of imaging mobility with this device.”
The idea was sparked by a scanner developed for studying rats, a project started in 2002 at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory. Majewski, a high-energy physicist by training, originally caught wind of Brookhaven’s “RatCAP” project because he ran in the same physicist circles as several of the RatCAP team members.
“I learned about what my friends and colleagues at Brookhaven were doing,” said Majewski, “and decided to build the same type of device for humans.”
The Rat Conscious Animal PET, or RatCAP, scanner is a 250-gram ring that fits around the head of a rat, suspended by springs to support its weight and let the rat scurry about as the device scans. Nora Volkow, head of Brookhaven’s Life Sciences division at the time, came up with the idea to image the brains of awake and moving animals.
“I wanted to do PET scans on animals without having to use anesthesia,” said Volkow, who is now the Director of the National Institute on Drug Abuse. Unlike humans, animals can’t be told to simply lie still in a scanner. But the anesthesia required to make them lie still muddies the results. “It affects the distribution of the PET…