Simultaneous measurement of angular and spectral properties of light scattering for characterization of tissue microarchitecture and its alteration in early precancer

We present a novel instrument to measure the spectral, angular, azimuthal, and polarization dependence of light backscattered by living biological tissues, thus providing the most comprehensive description of the light scattering to obtain unique quantitative information about the microarchitecture of living cells and tissues. We show the potential of this technique to characterize and diagnose early premalignant changes in the epithelia. In studies with a rodent model of colon carcinogenesis, we show that several parameters obtained using this technique, such as the number density of red blood cells in the capillary network immediately underlying the epithelium, the fractal dimension of the tissue, and the average roundness of subcellular structures, are significant for detection of precancerous changes at a very early stage of the carcinogenic process, at which no other histological or molecular markers have been identified.

I. Introduction

Static elastic light scattering has been widely used to probe the structure of a variety of materials. The properties of a single light scattering depend on the structure of the scatterer and can, thus, be used to characterize the scattering object. Over the last several years, there has been a significant interest in using light scattering to probe the structure and organization of living biological tissues. These studies aim to determine the information about the sizes and refractive indices of tissue components by measuring and analyzing the backscattered light from the tissue after a single scattering event. The reasons for the growing interest in using light scattering for tissue characterization are obvious. Such techniques may provide a noninvasive means to probe tissue structure in a wide range of scales without the need for tissue removal or processing. One particularly important potential application of light scattering is the diagnosis of precancerous epithelial lesions.