Phase function of biological soft tissues for the complete solid angle

With the help of a solution of the transport equation it is possible to calculate the light propagation in biological tissue quite precisely if the exact phase function of the scattering tissue is known. The phase function of most structured tissues depends on two scattering angles (polar and azimuthal angle) and the direction of the incident light. Even though the use of the complete phase function is crucial for a precise calculation of the light propagation and the only way to understand e.g. the anisotropic light propagation in structured tissue, typically phase functions are used which depend only on one scattering angle. This simplification is most likely due to missing measurement data of more realistic phase functions of biological tissues. In this article we present goniometric measurements of the phase function of porcine skeletal muscle for the whole solid angle and different incident directions.