A newly designed instrument, the static light-scattering (SLS) microscope, which combines light microscopy with SLS, enables us to characterize local light-scattering patterns of thin tissue sections. Each measurement is performed with an illumination beam of 70-μm diameter. On these length scales, tissue is not homogeneous. Both structural ordering and small heterogeneities contribute to the scattering signal. Raw SLS data consist of a two-dimensional intensity distribution map <i>I</i>(θ, ϕ), showing the dependence of the scattered intensity <i>I</i> on the scattering angle θ and the azimuthal angle ϕ. In contrast to the majority of experiments and to simulations that consider only the scattering angle, we additionally perform an analysis of the azimuthal dependence <i>I</i>(ϕ). We estimate different contributions to the azimuthal scattering variation and show that a significant fraction of the azimuthal amplitude is the result of tissue structure. As a demonstration of the importance of the structure-dependent part of the azimuthal signal, we show that this function of the scattered light alone can be used to classify tissue types with surprisingly high specificity and sensitivity.
© 2003 Optical Society of America
Alois K. Popp, Megan T. Valentine, Peter D. Kaplan, and David A. Weitz, "Microscopic Origin of Light Scattering in Tissue," Appl. Opt. 42, 2871-2880 (2003)