Making the Body Transparent
The mysteries of illness are revealed as never before
The throbbing of the brain to the beat of the heart, the coursing ofblood through a maze of vessels, the dance of molecules in a workingmuscle, the stealthy growth of a tumor. For generations doctors havehunted for ways to see through skin and bone and into the whirringprocesses of life. The discovery of the X ray in 1895 by WilhelmRoentgen opened the first window into the living body and inaugurated anew age in medicine. But anyone who has ever glanced at an X-ray filmcan perceive its Limitations. The picture gives little sense of depth,and while bones show up crisply enough, many of the softer tissues ofthe body are fuzzy shadows in shades of gray.
Ten years ago, doctors began to see more detail with a new kind of X-ray machine thatuses a computer to construct clear, cross-sectional views of the body.The CAT scanner revolutionizedradiology. But now that virtually every large hospital in the countryhas invested in one, at about a million dollars apiece, anotherrevolution is under way: Nuclear Magnetic Resonance, or NMR. Currentlybeing studied for approval by the Food and Drug Administration, the newtechnology is in experimental use at about half a dozen top U.S.medical centers as well as several overseas.
NMR exposes the internal landscape as never before. "Its development,"says British Radiologist Brian Worthington of the University of Nottingham,"is as significant as the development of the X-ray machine one hundredyears ago." Unlike CAT and other forms of X ray, NMR can "see" withclarity through the thickest of bones. Thus, without painful injectionsof contrast material, it can reveal damage from a stroke buried deepbeneath the skull, find tiny spinal cord injuries, and make it possibleto differentiate the gray and white matter of the brain. "For the softtissue of the body," says Worthington, "NMR comes close to being the perfect imaging technique."
The revelations offered by NMR go beyond anatomical topography. Not onlycan doctors see internal organs, they can actually monitor certainprocesses occurring within them: blood moving through an artery, anarthritis-inflamed knee shrinking in response to steroid treatment, thereaction of a malignant tumor to therapy. "NMR opens up the wholewonderful world of in vivo chemistry," exclaims Neuroradiologist SadekHilal, who is testing the new technique at New York City's Presbyterian Hospital.
What makes NMR'S revelations even more remarkable is that they areproduced without the ionizing radiation of X rays. In significantdoses, X radiation can damage cells and may be a factor in causingcancer; it may be particularly dangerous to the rapidly dividing cellsof children and pregnant women. NMR, by contrast, appears to beharmless. "We can look at the developing brain of an infant easily andsafely," says Dr. Robert Steiner of London's Hammersmith Hospital.
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