Laser Doppler measurements were performed on scattering liquids flowing through a highly scattering static medium to determine the scattering coefficient and the anisotropy factor of the liquids. Monte Carlo simulations of light propagation in the static and moving media were used to calculate the Doppler spectra for suspensions of polystyrene spheres in water, and these spectra were in excellent agreement with experimental results. A faster Monte Carlo code was developed so that nonlinear regressions to the measured laser Doppler spectra could be used to determine the anisotropy factor of other liquids. This approach was used to deduce the scattering properties of Intralipid and blood at λ = 820 nm. It was found that the anisotropy factor of blood is well described by Mie theory in contradiction to results reported in the literature that were obtained by goniometric measurement of the phase function.

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In this study we describe laser Doppler measurements on scattering liquids flowing through a highly scattering static medium to determine the scattering coefficient and the anisotropy factor of the liquids. Monte Carlo simulations of light propagation in the static and moving media were used to calculate the Doppler spectra. We show that the scattering coefficient of liquids can be derived from the integration of the Doppler spectrum provided that the absorption coefficient of the liquid is much smaller than the scattering coefficient. The anisotropy factor was deduced by applying an iterative nonlinear regression method to fit the measured Doppler spectra. The experimental setup was tested by comparing laser Doppler measurements on polystyrene spheres with Monte Carlo simulations. Finally, the scattering properties of dilute Intralipid20% and those of blood were determined at λ = 820 nm.