title: Effects of anisotropic optical properties on photon migration in structured tissues.
abstract: It is often adequate to model photon migration in human tissue in terms of isotropic diffusion or random walk models. A nearly universal assumption in earlier analyses is that anisotropic tissue optical properties are satisfactorily modelled by using a transport-corrected scattering coefficient which then allows one to use isotropic diffusion-like models. In the present paper we introduce a formalism, based on the continuous-time random walk, which explicitly allows the diffusion coefficients to differ along the three axes. The corrections necessitated by this form of anisotropy are analysed in the case of continuous-wave and time-resolved measurements and for both reflectance and transmission modes. An alternate model can be developed in terms of a continuous-time random walk in which the times between successive jumps differ along the three axes, but is not included here.
authors.affiliation: Mathematical and Statistical Computing Laboratory, Center for Information Technology, Bethesda, MD 20892-5626, USA.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Dagdug
authors.forename: George H
authors.initials: GH
authors.lastname: Weiss
authors.forename: Amir H
authors.initials: AH
authors.lastname: Gandjbakhche
mesh_terms: D016880:Anisotropy; D055592:Biophysical Phenomena; D001703:Biophysics; D006801:Humans; D008954:Models, Biological; D055095:Optics and Photonics; D017785:Photons; D012542:Scattering, Radiation; D014054:Tomography; D014172:Transillumination