Photon migration in non-scattering tissue and the effects on image reconstruction.

Photon propagation in tissue can be calculated using the relationship described by the transport equation. For scattering tissue this relationship is often simplified and expressed in terms of the diffusion approximation. This approximation, however, is not valid for non-scattering regions, for example cerebrospinal fluid (CSF) below the skull. This study looks at the effects of a thin clear layer in a simple model representing the head and examines its effect on image reconstruction. Specifically, boundary photon intensities (total number of photons exiting at a point on the boundary due to a source input at another point on the boundary) are calculated using the transport equation and compared with data calculated using the diffusion approximation for both non scattering and scattering regions. The effect of non-scattering regions on the calculated boundary photon intensities is presented together with the advantages and restrictions of the transport code used. Reconstructed images are then presented where the forward problem is solved using the transport equation for a simple two-dimensional system containing a non-scattering ring and the inverse problem is solved using the diffusion approximation to the transport equation.

[1]  R. A. Sawyer.  On the Deep Lying Terms in Two- and Three-Valence Electron System Spectra* , 1926 .

[2]  G. C. Pomraning,et al.  Linear Transport Theory , 1967 .

[3]  H. A. Ferwerda,et al.  Scattering and absorption of turbid materials determined from reflection measurements. 1: theory. , 1983, Applied optics.

[4]  R. Arridget,et al.  The theoretical basis for the determination of optical pathlengths in tissue: temporal and frequency analysis , 1992 .

[5]  S R Arridge,et al.  The theoretical basis for the determination of optical pathlengths in tissue: temporal and frequency analysis. , 1992, Physics in medicine and biology.

[6]  M. Schweiger,et al.  A finite element approach for modeling photon transport in tissue. , 1993, Medical physics.

[7]  R. S. Baker,et al.  DANTSYS: A diffusion accelerated neutral particle transport code system , 1995 .

[8]  K D Paulsen,et al.  Initial assessment of a simple system for frequency domain diffuse optical tomography. , 1995, Physics in medicine and biology.

[9]  M. Schweiger,et al.  The finite element method for the propagation of light in scattering media: boundary and source conditions. , 1995, Medical physics.

[10]  B. Pogue,et al.  Optical image reconstruction using frequency-domain data: simulations and experiments , 1996 .

[11]  Andreas H. Hielscher,et al.  Nondiffusive photon migration in homogeneous and heterogeneous tissues , 1996, European Conference on Biomedical Optics.

[12]  K.,et al.  Frequency-domain optical mammography: edge effect corrections. , 1996, Medical physics.

[13]  S R Arridge,et al.  An investigation of light transport through scattering bodies with non-scattering regions. , 1996, Physics in medicine and biology.

[14]  F Martelli,et al.  Independence of the diffusion coefficient from absorption: experimental and numerical evidence. , 1997, Optics letters.

[15]  Mamoru Tamura,et al.  Expression of optical diffusion coefficient in high-absorption turbid media , 1997 .

[16]  Randall L. Barbour,et al.  Transport and diffusion calculations on MRI-generated data , 1997, Photonics West - Biomedical Optics.

[17]  M. Tamura,et al.  Expression of optical diffusion coefficient in high-absorption turbid media. , 1998, Physics in medicine and biology.

[18]  S R Arridge,et al.  Optical imaging in medicine: I. Experimental techniques , 1997, Physics in medicine and biology.

[19]  J. Melissen,et al.  Tomographic image reconstruction from optical projections in light-diffusing media. , 1997, Applied optics.

[20]  M. Schweiger,et al.  Theoretical and experimental investigation of near-infrared light propagation in a model of the adult head. , 1997, Applied optics.

[21]  Oliver Dorn,et al.  A transport-backtransport method for optical tomography , 1998 .

[22]  S Arridge,et al.  A gradient-based optimisation scheme foroptical tomography. , 1998, Optics express.

[23]  R. Alcouffe,et al.  Comparison of finite-difference transport and diffusion calculations for photon migration in homogeneous and heterogeneous tissues. , 1998, Physics in medicine and biology.

[24]  Near-infrared imaging and optical properties of tissue phantoms having curved boundaries and clear layers , 1998 .

[25]  S. Arridge.  Optical tomography in medical imaging , 1999 .

[26]  M. Schweiger,et al.  The finite element model for the propagation of light in scattering media: a direct method for domains with nonscattering regions. , 2000, Medical physics.