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(above) MIT physicists have developed a powerful technique for detecting the earliest stages of cancer in the epithelium, the layer of tissue lining the inner surfaces of the body such as the colon and bladder. An estimated 85 percent of all cancers begin in the epithelium, which often serves as the body's first line of defense against invaders. The MIT technique can yield easy-to-read maps of normal, pre-cancerous, and cancerous epithelial tissue in blues, yellows, and reds. Shown here is an analysis of epithelial tissue from the colon; the pictured sample is 300 microns (millionths of a meter) wide.
(above) The entire MIT approach is based on light-scattering spectroscopy, a long-developed physics technique designed to measure the size and shape of tiny spheres such as water droplets. In the cancer-detection technique, a light probe shines white light on epithelial tissue. A portion of this light is deflected back ("backscattered") to the probe. The spectral content of this scattered light provides diagnostic information about the cell's nuclei, sphere-shaped organelles (shown in blue) which become enlarged and exhibit other changes during the early stages of cancer.
(above) Diagram of an advanced imaging device developed at MIT to provide a clean signal. A series of special light beams--created from white light with colored filters and a polarizer--are shined onto the patient's epithelium. For each color of light, an electronic camera (CCD) records a pair of images of the reflected light for two separate polarizations. The two images are then subtracted, which cuts out scattered background light and leaves behind only images related to the cell nuclei. (Thanks to MIT for supplying the above images and much of the figure captions.)
Reported by: Rajan Gurjar, Vadim Backman, Jacques Van Dam, Lev T. Perelman, and Michael S. Feld at the 2000 APS March Meeting in Minneapolis, Minnesota.