The level of the radioisotope was then measured using a positron emission tomography (PET) camera, which picks up the radioactive signal, shows exactly where the toluene is located in the body, and tracks its location over time. Other tissue-sampling methods were used to track the toluene as well.
The scientists were surprised by the findings. "I couldn't believe it," Dewey said. "The theory has always been that the effects of solvents would not be very specific -- that if you breathe them in they'd go everywhere equally," he said. "But, in fact, it looks like there's a regional distribution. They go to specific regions associated with reward and pleasure, just like other abused drugs. Then over time, they redistribute."
The initial specificity for the brain's reward centers may help to explain the addictive potential of inhalants, while the redistribution to the entire brain seems to mirror clinical changes observed in huffers. Unlike other drug abusers, who have damage in the reward centers, Dewey explained, "huffers have a much more global disease," with changes in areas of the brain that may interrupt normal learning and memory more quickly than other drugs.
In addition to offering insight into the nature and effects of inhalant abuse, Gerasimov said this study is also a technical advance in radiochemistry. "It's the first time chemists have labeled and purified a solvent for imaging," she said. This may open up a whole new field of study into the effects of a wide array of solvents found in common, everyday products from cleaning fluids to hairsprays. "There isn't a person among us who isn't exposed to solvents," Dewey said.