58 Monte Carlo modelling of photon propagation in a human head model containing an enhanced-absorbing target

Abstract

Introduction. Modelling the light propagation inside brain tissue structures is still a challenging task which requires the use of complex computational schemes often based on Monte Carlo method [ 1 Vaudelle F. and L’Huillier J.P. Time-resolved optical fluorescence spectroscopy of heterogeneous turbid media with special emphasis on brain tissue structures including diseased regions: a sensitivity analysis. Opt Comm. 304 161–168 (2013). Google Scholar , 2 Mansouri C, L’Huillier JP, Kashou NH, Humeau A. Depth sensitivity analysis of functional near-infrared spectroscopy measurement using three-dimensional Monte Carlo modelling based magnetic resonance imaging. Lasers Med Sci. 25, 431-438 (2010). Google Scholar , 3 Fang Q. Mesh-based Monte Carlo method using fast ray tracing in Plücker coordinates. Biomed Opt Exp. 1 165–175 (2010). Google Scholar ]. Because of strong tissue-scattering process (NIR infrared range: 600–900 nm), deep probed structures receive much less light amount than the superficial tissues. This has the effect to impede optical measurements and efficient planning treatments. In this paper, we take an interest in noninvasive tissue arrangements for which a NIR light source strikes a human head model, and thus investigate how photons penetrate and interact with an enhanced-absorbing target located close to the CSF layer. The study especially aims at displaying the effects of tissue structure, optical properties, location and size of the inclusion, dye concentration and light source parameters on optical diagnostic and therapeutic treatment.