Optical properties of normal and carcinomatous bronchial tissue

To understand better the optical characteristics and autofluorescence properties of normal and carcinomatous bronchial tissue, we measured the absorption coefficient, scattering coefficient, and anisotropy factor from 400 to 700 nm. We made the measurements by using an integrating sphere with a collimated white-light beam to measure total reflectance and transmittance of samples. The unscattered transmittance of the samples was measured through polarized on-axis light detection. The inverse adding-doubling solution was utilized to solve the equation of radiative transfer and to determine the absorption coefficient and reduced scattering coefficient. The scattering coefficient and anisotropy factor were derived from the unscattered transmittance of the sample and the reduced scattering coefficient. The measured parameters allow us to simulate photon propagation in normal bronchial and tumoral tissue by using Monte Carlo modeling.