Hybrid monte carlo–diffusion method for light propagation in tissue with a low–scattering region

Toshiyuki Hayashi, Yoshihiko Kashio, Eiji Okada

    Research output: Contribution to journalArticle

    80 Citations (Scopus)

    Abstract

    The heterogeneity of the tissues in a head, especially the low-scattering cerebrospinal fluid (CSF) layer surrounding the brain has previously been shown to strongly affect light propagation in the brain. The radiosity-diffusion method, in which the light propagation in the CSF layer is assumed to obey the radiosity theory, has been employed to predict the light propagation in head models. Although the CSF layer is assumed to be a nonscattering region in the radiosity-diffusion method, fine arachnoid trabeculae cause faint scattering in the CSF layer in real heads. A novel approach, the hybrid Monte Carlo–diffusion method, is proposed to calculate the head models, including the lowscattering region in which the light propagation does not obey neither the diffusion approximation nor the radiosity theory. The light propagation in the high-scattering region is calculated by means of the diffusion approximation solved by the finite–element method and that in the low–scattering region is predicted by the Monte Carlo method. The intensity and mean time of flight of the detected light for the head model with a low-scattering CSF layer calculated by the hybrid method agreed well with those by the Monte Carlo method, whereas the results calculated by means of the diffusion approximation included considerable error caused by the effect of the CSF layer. In the hybrid method, the time–consuming Monte Carlo calculation is employed only for the thin CSF layer, and hence, the computation time of the hybrid method is dramatically shorter than that of the Monte Carlo method.

    Original languageEnglish
    Pages (from-to)2888-2896
    Number of pages9
    JournalApplied Optics
    Volume42
    Issue number16
    DOIs
    Publication statusPublished - 2003 Jun 1

    ASJC Scopus subject areas

    • Atomic and Molecular Physics, and Optics
    • Engineering (miscellaneous)
    • Electrical and Electronic Engineering

    Fingerprint Dive into the research topics of 'Hybrid monte carlo–diffusion method for light propagation in tissue with a low–scattering region'. Together they form a unique fingerprint.

  • Cite this