Analysis of biomedical properties of tissues by the entropy factor for the detection of pathological diseases

Abstract

Imaging polarimetry is presently used in many different biomedical applications, like ophthalmology or dermatology, providing a non-invasive, non-contact and high-resolution diagnosis. Polarization techniques are based on the analysis of biological tissues by means of the Mueller matrix, which provides a complete description of the polarization properties, but this matrix does not supply a clear and comprehensive information about the physical and biological properties of tissues at first glance, and a slow and meticulous analysis of the matrix elements has to be accomplished to obtain a detailed characterization of their behavior. In this work, the entropy factor is defined and introduced for the analysis of biological tissues in order to handle one single parameter whose value is closely related to the tissue behavior, and therefore, provides a clearer analysis of the biological and physical modifications that take place in an unhealthy, old or heat-damaged tissue through its polarization characteristics. The entropy factor will be applied to the analysis of the Mueller matrices of different biological tissues obtained. Specifically, it is utilized for the characterization of different tissues, porcine tendon and rat tail, which has been analyzed in two situations, normal and burned, to observe if the entropy factor suffers a variation. This study is performed to provide a confident instrument to medical staff in biological and medical examination of tissues, so that a medical diagnosis can be realized through the study of this factor, providing in the next future an extra instrument for a complete development of optical biopsies by means of polarization techniques.