Finding the most probable diffuse path of photons in tissue by Monte Carlo method

With the increase using of light in detection biological tissue defect in deep and in vivo, it is necessary to find out the path of detection photons in order to find the exact position of the defect. The fundamental principles of photon migration in highly scattering media have been studied in the paper. The transport rule of photon energy in cuboid model has been studied by Monte Carlo method. 6 boundaries have been considered. Different with the half-infinite or highly symmetry models already exist cuboid model is much closer to the real condition. Based on which the most probable path of diffuse photons is more practical. Phantom experiments show the most probable path obtained from Monte Carlo method has the same veracity with the method already exist in the inside of the phantom. Near to the edge of the phantom, the existed method causes bigger error, while the new path can still locate the inhomogeneity exactly. The path can be used in locating the focus in breast cancer detection, convenient for biopsy or operations. In this paper the photon path was first discussed in a limited media with 6 boundaries, which is much closer to the real situation. Monte Carlo method, seldom used in photon path calculation, has been used in calculating the path exactly.