title: Finite-difference time-domain and steady-state analysis with novel boundary conditions of optical transport in a three-dimensional scattering medium illuminated by an isotropic point source.
abstract: We evaluate the numerical accuracy of finite-difference time-domain (FDTD) analysis of optical transport in a three-dimensional scattering medium illuminated by an isotropic point source. This analysis employs novel boundary conditions for the diffusion equation. The power radiated from an isotropic point source located at a depth equal to the reciprocal of the reduced scattering coefficient (1/μ'(s)) below the surface at the irradiated position is introduced to the integral form of the diffusion equation. Finite-difference approximations of the diffusion equation for a surface cell are derived by utilizing new boundary conditions that include an isotropic source even in a surface cell. Steady-state and time-resolved reflectances are calculated by FDTD analysis for a semi-infinite uniform scattering medium illuminated by an isotropic point source. The numerical results agree reasonably with the analytical solutions for μ'(s)=1-3 mm(-1) without resizing the mesh elements.
authors.affiliation: Electrical and Electronics Engineering Department, Kitami Institute of Technology, Kitami-City, Hokkaido, Japan. tanifuji@mail.kitami‐it.ac.jp
authors.forename: Tadatoshi
authors.initials: T
authors.lastname: Tanifuji
authors.forename: Shougo
authors.initials: S
authors.lastname: Tabata
authors.forename: Kazuya
authors.initials: K
authors.lastname: Okimatsu
authors.forename: Naoya
authors.initials: N
authors.lastname: Nishio
mesh_terms: D000818:Animals; D003952:Diagnostic Imaging / Q000379:methods*; D020342:Finite Element Analysis; D006801:Humans; D015233:Models, Statistical; D008962:Models, Theoretical; D055095:Optics and Photonics; D012542:Scattering, Radiation; D013997:Time Factors; D014054:Tomography / Q000379:methods