Modelling of light distribution in the brain for topographical imaging

Eiji Okada, Toshiyuki Hayashi, Hiroshi Kawaguchi

    Research output: Contribution to journalConference articlepeer-review


    Multi-channel optical imaging system can obtain a topographical distribution of the activated region in the brain cortex by a simple mapping algorithm. Near-infrared light is strongly scattered in the head and the volume of tissue that contributes to the change in the optical signal detected with source-detector pair on the head surface is broadly distributed in the brain. This scattering effect results in poor resolution and contrast in the topographic image of the brain activity. We report theoretical investigations on the spatial resolution of the topographic imaging of the brain activity. The head model for the theoretical study consists of five layers that imitate the scalp, skull, subarachnoid space, grey matter and white matter. The light propagation in the head model is predicted by Monte Carlo simulation to obtain the spatial sensitivity profile for a source-detector pair. The source-detector pairs are one-dimensionally arranged on the surface of the model and the distance between the adjoining source-detector pairs are varied from 4 mm to 32 mm. The change in detected intensity caused by the absorption change is obtained by Monte Carlo simulation. The position of absorption change is reconstructed by the conventional mapping algorithm and the reconstruction algorithm using the spatial sensitivity profiles. We discuss the effective interval between the source-detector pairs and the choice of reconstruction algorithms to improve the topographic images of brain activity.

    Original languageEnglish
    Article number5486-01
    Pages (from-to)1-9
    Number of pages9
    JournalProgress in Biomedical Optics and Imaging - Proceedings of SPIE
    Issue number30
    Publication statusPublished - 2004 Dec 1
    EventALT'03 International Conference on Advanced Laser Technologies: Biomedical Optics - Silsoe, United Kingdom
    Duration: 2003 Sept 192003 Sept 23


    • Near infrared spectroscopy
    • Spatial sensitivity profile
    • Topographic imaging

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Biomaterials
    • Atomic and Molecular Physics, and Optics
    • Radiology Nuclear Medicine and imaging


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