IMPROVED SOLUTIONS OF THE STEADY-STATE AND THE TIME-RESOLVED DIFFUSION-EQUATIONS FOR REFLECTANCE FROM A SEMIINFINITE TURBID MEDIUM

Improved solutions of the diffusion equation for time-resolved and ste ady-state spatially resolved reflectance are investigated for the dete rmination of the optical coefficients of semi-infinite turbid media su ch as tissue. These solutions are derived for different boundary condi tions at the turbid-medium-air interface and are compared with Monte C arlo simulations. Relative reflectance data are fitted in the time dom ain, whereas relative and absolute reflectance are investigated in the steady-state domain. It is shown that the error in deriving the optic al coefficients is, especially for steady-state spatially resolved ref lectance, considerably smaller for the solutions under study than for the commonly used solutions. Analysis of experimental measurements of absolute steady-state spatially resolved reflectance confirms these re sults. (C) 1997 Optical Society of America.