The radial dependence of the diffuse reflectance from a turbid medium that is due to a point source is basically influenced by the absorption and reduced scattering coefficients. A system consisting of a HeNe laser source and a CCD camera is described for making remote measurements of the spatially resolved diffuse reflectance. Liquid tissue phantoms were made of Intralipid and trypan blue to validate the experimental setup. We show that for the correct determination of the optical properties of the tissue phantoms, the point-spread function (PSF) of the camera system has to be considered. Convolving the PSF with a solution of the diffusion equation, the absorption and reduced scattering coefficients of the tissue phantoms could be determined with an average error of 8% in the absorption coefficient and 4% in the reduced scattering coefficient, whereas without convolution, the errors were considerably larger, especially for large optical parameters.
The absorption and reduced scattering coefficients determine the radial dependence of the diffuse reflectance that is due
to a point source. A system consisting of a HeNe laser source and a CCD camera was built for making remote
measurements of spatially resolved diffuse reflectance. First, liquid tissue phantoms were made of Lipovenös and trypan
blue. To determine the optical properties of the tissue phantoms a program code was implemented convolving the pointspread
function of the camera with the solution of the diffusion equation and fitting the result to the measured data. We
found that the prediction of &mgr;a and &mgr;s' was accurate within ± 10 % and ± 4 %. To check these results also measurements
with a multiple fiber-optic detector in contact with the phantom surface at varying distances from the source were
accomplished. The intensity signal was measured with twelve low noise photodiodes. We found good agreement
between both approaches.
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