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

78 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 low-scattering 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
Publication statusPublished - 2003 Jun 1

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cerebrospinal fluid
Cerebrospinal fluid
Light propagation
Scattering
Tissue
propagation
scattering
Monte Carlo method
Monte Carlo methods
brain
Brain
approximation
finite element method
Finite element method
causes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Hybrid Monte Carlo-diffusion method for light propagation in tissue with a low-scattering region. / Hayashi, Toshiyuki; Kashio, Yoshihiko; Okada, Eiji.

In: Applied Optics, Vol. 42, No. 16, 01.06.2003, p. 2888-2896.

Research output: Contribution to journalArticle

Hayashi, Toshiyuki ; Kashio, Yoshihiko ; Okada, Eiji. / Hybrid Monte Carlo-diffusion method for light propagation in tissue with a low-scattering region. In: Applied Optics. 2003 ; Vol. 42, No. 16. pp. 2888-2896.
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