We used MCS as the foundation to determine reliable values of , , , and . The simulation model used here consisted of a single layer of cortical tissue, in which and are homogeneously distributed. The absorption coefficients converted from the concentrations and and the reduced scattering coefficient deduced by the coefficient and the exponent were provided as inputs to the simulation, whereas the diffuse reflectance spectrum was derived as output. The input values of , , , and and the output reflectance spectra are useful as the data set in statistically determining the values of , , , and for determining the absolute values of , , , and . The five different values of 60,258, 80,344, 100,430, 120,516, and 180,774 were calculated by multiplying the typical value40 of by 0.5, 0.75, 1.0, 1.25, and 1.5, respectively, whereas the five values of 1.2442, 1.31332, 1.3824, 1.45156, and 1.52068 were calculated by multiplying the typical value40 of by 0.5, 0.75, 1.0, 1.25, and 1.5, respectively. The reduced scattering coefficients of the cortical tissue with the 25 different values were derived using Eq. (15). The sum of the absorption coefficients of oxyhemoglobin and deoxyhemoglobin for , 23.26, and was used as input to the cortical tissue in the simulation. Tissue oxygen saturation StO2 was determined by , and values of 0%, 20%, 40%, 60%, 80%, and 100% were used for the simulation. The above values were also used for the refractive index of the cortical layer. In total, 450 diffuse-reflectance spectra at , 520, 540, 560, 570, 580, 600, 730, and 760 nm were simulated under the various combinations of , , , and . The MRA1 analysis for each simulated spectrum based on Eq. (16) generated the 450 sets of vector and concentrations and and exponent , and the 450 sets of vector and coefficient . The coefficient vectors , , and were statistically determined by performing MRA2, whereas the coefficient vector was determined statistically by performing MRA3. Once , , , and were obtained, , , , and were calculated from , , and , which were derived from MRA1 for the measured reflectance spectrum, without the MCS, as shown in Fig. 1(b). Therefore, the spectrum of the reduced scattering coefficient and that of the absorption coefficient were reconstructed by Eqs. (12) and (15), respectively, from the measured reflectance spectrum.