Diffuse reflectance spectroscopy of human adenomatous colon polyps in vivo

Diffuse reflectance spectra were collected from adenomatous colon polyps (c ancer precursors) and normal colonic mucosa of patients undergoing colonosc opy. We analyzed the data by using an analytical light diffusion model, whi ch was tested and validated on a physical tissue model composed of polystyr ene beads and hemoglobin. Four parameters were obtained: hemoglobin concent ration, hemoglobin oxygen saturation, effective scatterer density, and effe ctive scatterer size. Normal and adenomatous tissue sites exhibited differe nces in hemoglobin concentration and, on average, in effective scatterer si ze;which were in general agreement with other studies that employ standard methods. These results suggest that diffuse reflectance can be used to obta in tissue information about tissue structure and composition in vivo. (C) 1 999 Optical Society of America.