Modeling of Light Distribution in Tissue by Monte Carlo Simulation

Abstract

Laser has got a property of having high irradiance and penetration power to be used for different medical purposes such as diagnostic, imaging, and treatment of several diseases. When laser interacts with tissue (considering particle nature of laser light), photons get absorbed, scattered or transmitted depending upon optical properties of the tissue. For laser treatment, information such as fluence rate, reflectance, power, spot size etc. should be known a priori. The optical properties of tissue affect the photon distribution inside the tissue. Therefore, Monte Carlo method is used to simulate photon distribution. The effect of variation of scattering coefficient, anisotropy, and refractive index of tissue (optical properties) on fluence rate and reflectance is studied. The scattering coefficient variation shows changes in fluence rate, in which penetration of photon is high for lower scattering coefficient and decreases as the coefficient increases. Photons get evenly distributed for lower value of anisotropy of the tissue. Parametric studies suggested that refractive index did not have significant effect on the fluence rate and the reflectance.