title: Perturbation and differential Monte Carlo methods for measurement of optical properties in a layered epithelial tissue model.
abstract: The use of perturbation and differential Monte Carlo (pMC/dMC) methods in conjunction with nonlinear optimization algorithms were proposed recently as a means to solve inverse photon migration problems in regionwise heterogeneous turbid media. We demonstrate the application of pMC/dMC methods for the recovery of optical properties in a two-layer extended epithelial tissue model from experimental measurements of spatially resolved diffuse reflectance. The results demonstrate that pMC/dMC methods provide a rapid and accurate approach to solve two-region inverse photon migration problems in the transport regime, that is, on spatial scales smaller than a transport mean free path and in media where optical scattering need not dominate absorption. The pMC/dMC approach is found to be effective over a broad range of absorption (50 to 400%) and scattering (70 to 130%) perturbations. The recovery of optical properties from spatially resolved diffuse reflectance measurements is examined for different sets of source-detector separation. These results provide some guidance for the design of compact fiber-based probes to determine and isolate optical properties from both epithelial and stromal layers of superficial tissues.
authors.affiliation: University of California, Irvine, Department of Chemical Engineering and Materials Science, Irvine, California 92697, USA.
authors.forename: InSeok
authors.initials: I
authors.lastname: Seo
authors.forename: Joon S
authors.initials: JS
authors.lastname: You
authors.forename: Carole K
authors.initials: CK
authors.lastname: Hayakawa
authors.forename: Vasan
authors.initials: V
authors.lastname: Venugopalan
mesh_terms: D001718:Birefringence; D003198:Computer Simulation; D004848:Epithelium / Q000502:physiology*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008027:Light; D008859:Microscopy, Polarization / Q000295:instrumentation / Q000379:methods*; D008954:Models, Biological; D009010:Monte Carlo Method; D009391:Nephelometry and Turbidimetry / Q000295:instrumentation / Q000379:methods*; D019047:Phantoms, Imaging; D012031:Refractometry / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity