Development of low-coherence enhanced backscattering platform for tissue spectroscopic imaging and characterization

As a spectacular manifestation of self-interference effects in elastic light scattering, enhanced backscattering of light (EBS, also known as coherent backscattering of light) has been intensively investigated for characterization of strongly scattering medium. By using low spatial coherence illumination, EBS has further shown its potential for biological tissue characterization and cancer diagnosis. First, using low-coherence enhanced backscattering (hereafter referred to as LEBS), the development of an optical imaging platform is presented. LEBS imaging platform takes the advantage of self-generated multiple independent coherence areas, which can be used as spatial filters as similarly as mechanical pinhole scanning. Thus, this imaging platform substantially minimizes cross-talk among adjacent pixels, rejects the background light caused by out-of-plane scattered light, and allows optical-sectioning to the subsurface in a relatively large area. These interesting capabilities of the LEBS imaging platform are validated by tissue phantom experiments. Second, the presented work further describes a detailed analysis of LEBS for better understanding possible mechanisms by which LEBS probes subtle variations in radial intensity distribution in weakly scattering medium such as biological tissue. The result from a pilot study using an animal model of chemical skin carcinogenesis shows that the enhancement factor of LEBS can be strongly altered even at a stage of preneoplasia, preceding the classical biomarker of non-melanoma skin cancer