Measurements of scattering effects within tissue-like media at two wavelengths of 632.8 nm and 680 nm

Measurements have been performed in order to determine the effective attenuation coefficient mu(eff) and the scattering phase function S(theta) for different mixtures of Intralipid-10% and -20% (scattering medium) and ink (absorbing medium) at wavelengths of 632.8 nm and 680 nm. Particle size distributions have been recorded by means of a nanosizer type apparatus for the fat Intralipid emulsions and for the mixtures of Intralipid showing that the Mie theory may be applied in these conditions. The evolution of the effective attenuation coefficient mu(eff) has been plotted against the concentration of Intralipid emulsions in distilled water, with or without an added absorber. However, the evolution of the anisotropy coefficient g, deduced from S(theta), was only studied as a function of the concentration of an added absorber. The overall results demonstrate that the relationship between mu(eff) and the concentration of the dilution of the Intralipid emulsions is not linear. In contrast, the anisotropy coefficient g remains stable independently of the amount of an added absorber. These findings agree qualitatively with those reported by other authors, the few observed differences can be mainly attributed at least in part to the dispersion in Int ralipid-10% composition.