Although excellent images of the brain are possible, it is not possible to distinguish between gray matter, which is responsible for cognitive function, and white matter, which is associated with motor function. With one thousand times fewer nuclei but one thousand times higher magnetization, helium-3 gas makes lung cavity images possible. The subject simply inhales the polarized helium gas and holds it for a few seconds while a magnetic resonance image of the helium is acquired. Xenon, on the other hand, is highly soluble in the blood and in white matter of the brain. Tens of seconds after inhaling xenon, a concentration accumulates in the white matter, allowing selective imaging of this important structure.
Xenon is a known anesthetic.
By producing images of xenon concentrations and measuring small shifts in the xenon resonance frequency that characterize the local chemistry, we hope to determine the mechanism for anesthesia. We also hope to contribute to the discovery of new diagnostic techniques for understanding white matter degeneration and disease, such as Parkinson's disease. We have begun collaborating with teams at the Brigham and Women's Hospital and the Harvard-Smithsonian Astrophysical Observatory to develop these promising techniques. Our MRI studies are supported by UNH while we seek funding from the federal agencies. The two main theoretical investigations of the UNH Nuclear Physics Group explore two different extreme regimes.