By Janet Raloff
The difference between slightly abnormal tissue and precancerous tissue can be subtle. Because the changeover may not be visible to the naked eye, surgeons exploring questionable tissue remove a tiny sample for a biopsy–a detailed examination by a trained pathologist. If some biomedical researchers have it their way, physicians will one day be able to scout for precancerous cells by simply shining light on them.
Boston-area researchers are developing a new technology that could become the basis for such optical biopsies. In less than 1 second, the device these scientists have built beams 12 colors of light sequentially down a cable of optical fibers and onto the tissue the fibers are touching. Each pulse excites certain chemicals in the tissue. The chemicals instantly respond by emitting characteristic fluorescent flashes, which the cable transmits back to a central processor.