Microspectroscopic measurement of the optical properties of rat liver in the visible region.

Microspectroscopy is used to investigate optical properties of haemoglobin-free perfused rat liver. Visible spectra of 20 microns diameter spot size were measured in transmission and/or reflection modes as a function of the thickness (< 1200 microns) of the liver-edge. Optical density (OD) in transmission mode increased with the increasing liver thickness, whereas in reflection mode OD decreased but became almost constant above a certain thickness (c.600 microns) of the liver. The Kubelka-Munk (KM) two-flux model, with a minor modification, was applied successfully to the analysis of the changes in OD as a function of the thickness. This approach estimates the KM absorption coefficient (EKM), KM scattering coefficient (SKM) and effective penetration depth (delta eff) of the liver. The optical properties were similar to reported values, obtained with different methods.