抄録
Near infrared spectroscopy and imaging have been applied to measure brain activities. The light scattering in the tissue causes ambiguity in the volume of tissue sampled with a source-detector pair of near infrared instruments and hence theoretical modelling to obtain light propagation in the head is very important for the brain activity measurements. In this paper two theoretical methods, Monte Carlo simulation and hybrid Monte Carlo-diffusion method, for calculation of light propagation in the brain are reviewed. The light propagation in the brain is strongly affected by the heterogeneity of tissue, especially the presence of low scattering cerebrospinal fluid (CSF). The results indicate that the presence of the CSF layer improves the sensitivity of the optical signal to brain activities.
