title: Determination of the optical properties of a two-layer tissue model by detecting photons migrating at progressively increasing depths.
abstract: We have investigated a method for solving the inverse problem of determining the optical properties of a two-layer turbid model. The method is based on deducing the optical properties (OPs) of the top layer from the absolute spatially resolved reflectance that results from photon migration within only the top layer by use of a multivariate calibration model. Then the OPs of the bottom layer are deduced from relative frequency-domain (FD) reflectance measurements by use of the two-layer FD diffusion model. The method was validated with Monte Carlo FD reflectance profiles and experimental measurements of two-layer phantoms. The results showed that the method is useful for two-layer models with interface depths of >5 mm; the OPs were estimated, within a relatively short time (<1 min), with a mean error of <10% for the Monte Carlo reflectance profiles and with errors of <25% for the phantom measurements.
authors.affiliation: Department of Laser Applications in Medicine, National Institute of Enhanced Laser Sciences, Cairo University, Cairo, Egypt. laser@internetegypt.com
authors.forename: Yasser S
authors.initials: YS
authors.lastname: Fawzi
authors.forename: Abo-Bakr M
authors.initials: AB
authors.lastname: Youssef
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: el-Batanony
authors.forename: Yasser M
authors.initials: YM
authors.lastname: Kadah
mesh_terms: D000465:Algorithms; D003238:Connective Tissue / Q000033:anatomy & histology* / Q000502:physiology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D009010:Monte Carlo Method; D055095:Optics and Photonics / Q000295:instrumentation*; D019047:Phantoms, Imaging; D017785:Photons; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D041622:Tomography, Optical / Q000295:instrumentation* / Q000379:methods*