MEASUREMENT OF THE OPTICAL-PROPERTIES OF THE SKULL IN THE WAVELENGTH RANGE 650-950 NM

The optical properties of samples of bone from pig skull have been measured over the wavelength range 650-950 nm. The scattering phase function was measured on thin samples of the bone using a goniometer, and a value for the mean cosine g, of the scattering angle, was calculated. The scattering and absorption coefficients, mu(s) and mu(a) were then determined from measurements of diffuse reflectance and transmittance made with a pair of integrating spheres, by a step-wise search through a table of diffuse reflectance and transmittance versus mu(a) and mu(s) generated by a Monte Carlo model incorporating the measured scattering phase function. Values for g measured on six samples varied from 0.925 +/- 0.014 at 650 nm to 0.945 +/- 0.013 at 950 nm. Corresponding values for mu(a) and mu(s) measured on 18 samples were mu(a) = 0.04 +/- 0.002 mm-1, mu(s) = 35 +/- 0.7 mm-1 at 650 nm to mu(a) = 0.05 +/- 0.002 mm-1, mu(s) = 24 +/- 0.6 mm-1 at 950 nm.