the noble gas xenon, polarized by a laser, and then inhaled by a rat, lights lungs and heart as seen in the front (first row) and top views. differences in xenon concentration in the blood (A and D), tissues (B and E), and gas (C and F) provides
a TLANTA - Known for cartoon enthusiasts as a powerful superhero, xenon - in real life, a noble gas mild-mannered - may soon turn his super powers to medicine. Physicists xenon used to generate images of blood flow through the heart, lungs and brain tissue in rats. The research, presented yesterday at a meeting of the American Physical Society, could be a promising alternative to diagnose human disease through high-resolution imaging by magnetic resonance imaging (MRI).
xenon, an inert gas, is evaluated by doctors for its anesthetic properties. In 1994, a team led by chemist Albert Mitch of New York State University at Stony Brook, has shown that xenon can also switch the airflow in the lungs, which escapes MRI techniques standard. The team "hyperpolarized" xenon atoms with a laser beam, align their spins to improve their responses to a magnetic probe. In this way, the MRI inhaled xenon help sweep the air-filled cavities. Another group found last year that xenon and helium noble gases can produce clear signals in magnetic fields much lower than those used in today bulky MRI machine ( Science NOW, October 22, 1998).
now, the researchers found that xenon can trace how the gases flow through the barrier between the blood and tissues, and between the fabric and the air. Biophysical chemist Scott Swanson of the University of Michigan, Ann Arbor, and colleagues injected tiny doses of hyperpolarized xenon in the lung of a rat immobilized in an MRI probe. polarized xenon atoms remain in the body for 30 seconds, long enough for the gas to be absorbed into the bloodstream and circulate through the tissues of blood-rich organs. Subtle differences in the shapes of polarized atoms in every medium - air, blood and tissues - leaving the image of the team blood models that run through the heart, lungs and brain of rats. "This could be very useful to identify bottlenecks in normal blood and air flow" as in emphysema and fibrosis, says Swanson. These features appear hazy using current technologies.
Probing how the brain and other organs with xenon has "enormous potential," says atomic physicist Gordon Cates from Princeton University in New Jersey. "the noble gases can give us much greater resolution than fMRI methods used today, "he said. the US Food and Drug Administration has yet to approve the xenon for use in clinical trials MRI, Cates note. he thinks it will not be a problem, because patients already inhale xenon to improve brain scans using positron, another imaging technique.
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