Integrating the digitized backscattered image to measure absorption and reduced-scattering coefficients in vivo

Measurement of absorption and reduced-scattering optical coefficients mu(a) and mu(s)' is possible when a steady-state backscattered image is used on a sample surface. A new method for processing the backscattered image, acquired with a CCD, has been developed. The image is integrated to decrease sensitivity to noise. The resulting curve is defined as the integral reflectance. The curve is then fitted with a relaxation model to evaluate mu(a) and mu(s)'. We have validated the method with calibrated scattering and absorption phantoms. The integral reflectance method is then applied to measurements of the mu(a) and mu(s)' coefficients of human skin in vivo. (C) 1999 Optical Society of America.