Optical properties of nasal septum cartilage.

Optical parameters (scattering coefficient a, absorption coefficient k and scattering anisotropy coefficient g) of hyaline cartilage were studied for the first time. Optical properties of human and pig nasal septum cartilage, and of bovine ear cartilage were examined using a spectrophotometer with an integrating sphere, and an Optical Multi-Channel Analyser. We measured total transmission T-t, total reflection R-t and on-axis transmission T-a for light propagating through cartilage sample, over the visible spectral range (14000-28000 cm(-1)). It is shown that transmission and reflection spectra of human, pig and bovine cartilage are rather similar. It allows us to conclude that the pig cartilage can be used for in-vivo studies instead of human cartilage. The data obtained were treated by means of the one-dimensional diffusion approximation solution of the optical transport equation. We have found scattering coefficient s, absorption coefficient k and scattering anisotropy coefficient g by the iterative comparison of measured and calculated T-t, R-t and T-a values for human and pig cartilage. We found, in particular, that for 500 nm irradiation s=37,6+/-3.5cm(-1), g=0,56 +/- 0.05, k congruent to 0,5+/-0.3 cm-1. The above data were used in Monte Carlo simulation for spatial intensity profile of light scattered by a cartilage sample. The computed profile was very similar to the profile measured using an Optical Multi-Channel Analyzer (OMA).