Influence of the phase function on determination of the optical propertiesof biological tissue by spatially resolved reflectance

Spatially resolved reflectance measurements are widely used for determinati on of the optical properties of biological media. However, the influence of the phase function on these measurements has not been quantified. We show that errors in the derived. reduced scattering and absorption coefficients are as great as 100% for both absolute and relative spatially resolved refl ectance measurements if a standard solution of the diffusion equation is us ed in the analysis. In addition, we investigated nonlinear regressions, usi ng Monte Carlo simulations and an additional fitting parameter that charact erizes the phase function, and found that the errors in the obtained optica l coefficients were less than or equal to 20%. (C) 2001 Optical Society of America.