Turbid medium polarimetry in biomedical imaging and diagnosis

Studies on polarization properties of scattered light from a random medium like biological tissue have received considerable attention because polarization can be used as an effective tool to discriminate against multiply scattered light (acting as a gating mechanism) and thus can facilitate high resolution imaging through tissue. Further, the polarization properties of scattered light from tissue contain wealth of morphological and functional information of potential biomedical importance. However, in a complex random medium like tissue, numerous complexities due to multiple scattering and simultaneous occurrences of many scattering and polarization events present formidable challenges both in terms of accurate measurements and in terms of analysis of the tissue polarimetry signal. Several studies have therefore been conducted in the recent past to develop appropriate measurement procedures, suitable light propagation models and polarimetry signal analysis methods to overcome these difficulties. In this review, we focus on some of the recent key developments in this area. Specifically, we describe variety of theoretical and experimental tools, illustrated with selected results, aimed at evaluating the prospect of turbid medium polarimetry for both biomedical imaging and diagnosis.