Los Alamos National Laboratory
Jim Danneskiold
(505) 667-1640 / [email protected]
LOS ALAMOS UNVEILS NEW BRAIN-IMAGING SYSTEM
ALBUQUERQUE, N.M., April 7, 1998 - The U.S. Department of Energy's Los Alamos National Laboratory today unveiled a new medical instrument that will help physicians assess patients with brain injuries and diseases and even help solve the mysteries of how the brain works.
At the Albuquerque Veterans Affairs Medical Center, Sen. Pete Domenici, R-N.M., inspected Los Alamos' new whole-head magnetoencephalography sensor system. The system incorporates new concepts that should reduce the cost of such instruments from about $3 million to less than $500,000 and allow many more patients to benefit from the brain-imaging system.
Magnetoencephalography, or MEG, is a method of measuring the tiny magnetic fields produced when groups of the brain's 100 billion or so cells, or neurons, are active. Those fields, a billion times smaller than Earth's magnetic field and 10,000 times smaller than the field surrounding a household wire, are generated by electrical currents that result from thought, the sound of music, the impulse to move a muscle and other types of brain activity.
MEG scans can help neurosurgeons pinpoint areas associated with brain injury or functional abnormalities such as epilepsy and help researchers study such disorders as Parkinson's disease, multiple sclerosis and schizophrenia. It supplements with functional maps of brain activity other imaging techniques such as Magnetic Resonance Imaging, or MRI, which displays brain anatomy.
The Los Alamos system looks like a helmet and contains 155 ultra-sensitive sensors, known as superconducting quantum interference devices, or SQUIDs. Atop the helmet is a unique shield that screens out electrical and magnetic interference and an instrument column immersed in liquid helium that maintains the SQUIDs at minus-450 degrees F.
The SQUIDs record the magnetic fields produced by active neurons and display the fields as topographic maps. Computer models are used to calculate the locations and durations of brain activity and project maps of those active neurons on three-dimensional MRI images of the brain.
"SQUIDs are the most sensitive magnetic field detectors known," said Bob Kraus of Los Alamos' Biophysics Group, MEG principal investigator. "They detect and then convert the weak magnetic fields from neural activity into electrical signals that can be measured more easily."
Los Alamos researchers have been working to improve MEG instruments and the computational methods used to analyze MEG data for nearly 15 years. Several Los Alamos concepts are being applied in a clinical setting at the VA Medical Center's Neuroimaging Center.
Los Alamos, the VA center, the University of New Mexico and Sandia National Laboratories have worked together to quadruple the number of patients who can use the system, from three a week to 12. Los Alamos also has improved its computational methods to permit more sophisticated analysis of clinical magnetoencephalography data.
Previous MEG systems have required costly, specially constructed rooms to shield SQUID sensors from external magnetic fields, such as those generated by building wiring and lighting systems. Los Alamos' latest breakthrough, a patented superconducting imaging surface, is a unique superconducting shield that repels interfering magnetic fields at the same time that it focuses the magnetic fields generated by brain activity, greatly reducing the time needed to measure brain activity.
The shield incorporates a cryogenic material similar to Corian, commonly used for kitchen countertops in luxury homes. Los Alamos holds a joint patent for the material with DuPont Corp.
"We like to say that our new system has everything including the kitchen sink," Kraus joked.
Los Alamos has completed preliminary tests of the new full-head MEG system, which is ready to begin initial measurements of human subjects. After those tests, the new system will be installed at the Albuquerque VA Center for clinical trials.
Using sophisticated computer algorithms from Los Alamos, VA researchers "fuse" MEG measurements with three-dimensional MRI data to view brain cell activity together with brain anatomy. Such computational improvements increase the amount of data from each measurement, as well as researchers' understanding of the data.
Los Alamos plans to use photolithography techniques, like those used to make electronic circuits, to etch onto the inside of the helmet the conducting loops that register the brain's magnetic signals. This will allow manufacturers to mass-produce the sensor surfaces and place more sensors in the helmet. More sensors reduce the time needed to make measurements and increase the amount of information available.
Funding for Los Alamos' MEG research initially came from Los Alamos' internal Laboratory-Directed Research and Development program. Subsequent support has come from the DOE's Office of Biological and Environmental Research, the National Institute of Neurological Disorders and Stroke and other institutes of the National Institutes of Health.
Kraus and his colleagues are working on several future applications for MEG systems, SQUID sensors and their superconducting imaging surface. These include devices for imaging magnetic fields of the heart and breast to supplement electrocardiograms and mammograms; portable systems for emergency or battlefield imaging; devices for early detection of fetal brain and heart abnormalities; and SQUID devices for non-destructive evaluation and testing of components in aircraft or nuclear weapons.
Los Alamos National Laboratory is operated by the University of California for the U.S. Department of Energy. -30-
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