ABSTRACT
Nirmalya Ghosh, Michael Wood, and Alex Vitkin Ontario Cancer Institute / Department of Medical Biophysics University of Toronto, Toronto, Ontario, Canada
9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254 9.2 Mueller Matrix Preliminaries and the Basic Polarization Parameters . . . . . . . . . . . . . . . . . . . . . . 255 9.3 Polar Decomposition of Mueller Matrices for Extraction of the Individual Intrinsic
Polarization Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258 9.4 Sensitive Experimental System for Mueller Matrix Measurements in Turbid Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261 9.5 Forward Modeling of Simultaneous Occurrence of Several Polarization Effects in Turbid
Media Using the Monte Carlo Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264 9.6 Validation of the Mueller Matrix Decomposition Method in Complex Tissue-Like Turbid
Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267 9.7 Selected Trends: Path length and Detection Geometry Effects on the Decomposition-Derived Polarization Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 9.8 Initial Biomedical Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274 9.9 Concluding Remarks on the Prospect of the Mueller Matrix Decomposition Method in
Polarimetric Assessment of Biological Tissues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280
Polarization parameters of light scattered from biological tissue contain rich morphological and functional information of potential biomedical importance. Despite the wealth of interesting parameters that can be probed with polarized light, in optically thick turbid media such as tissues, numerous complexities due to multiple scattering and simultaneous occurrence of many polarization effects present formidable challenges, both in terms of accurate measurement and in terms of extraction / unique interpretation of the polarization parameters. In this chapter, we describe the application of an expanded Mueller matrix decomposition method to tackle these complexities. The ability of this approach to delineate individual intrinsic polarimetry characteristics in tissue-like turbid media (exhibiting multiple scattering, and linear and circular birefringence) was validated theoretically with a polarized-light propagation model and experimentally with a polarization-modulation/synchronous detection technique. The details of the experimental turbid polarimetry system, forward Monte Carlo modeling, inverse polar decomposition analysis, and the results of the validations studies are presented in this chapter. Initial applications of this promising approach in two scenarios of significant clinical interest, that for monitoring regenerative treatments of the
of Photonics for Biomedical
heart and for noninvasive glucose measurements, as well as initial in vivo demonstration, are discussed.
