The purpose of this study is to implement the Monte Carlo (MC) technique to simulate the transient radiative transport in non-homogeneous participating media: absorbing, scattering and non-emitting, such as biological tissues. The MC algorithm is a stochastic method using random numbers to represent the physical phenomena. The major advantage of MC method is its flexibility and simplicity to simulate the photon movement in arbitrary geometry and complex boundary condition. Initially, one-dimensional multi-layered slab has been examined. The MC results have good agreement with Discrete Ordinate Method (DOM) results. The temporal spreads of the transmittance and reflectance of a pulsed, collimated incident beam are obtained. The evident drawback of the MC method is time-consumed in computation process and computer memory requirement.; The parallel algorithm is implemented in a Beowulf class PC cluster to improve the solution accuracy and efficiency. The parallel system is a cluster of commodity-class processors built with a standard Massage-Passing-Interface (MPI). MPI is a library of subprograms. It is chosen as a tool to implement parallel programming for its portability to other parallel systems. The three-dimensional Monte Carlo code for multidimensional geometry and complex radiative property distribution is then developed. The verification of the multidimensional results for the case with infinite height and width shows good agreement with the one-dimensional results. Parametric studies of reflectance and transmittance using different radiative properties, aspect ratios, detecting locations and solid angles are shown.; Eventually, the ultimate objective is to compare the prediction from numerical simulations with the experimental temporal transmitted and reflected signals for a short pulse laser source incident on tissue phantoms.
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