Simulation of optical and thermal responses of laser irradiated tissue

Abstract

A Java Simulation Application was developed to simulate optical and thermal response of laser irradiated tissue by using Monte Carlo and Finite Difference Methods. For light propagation Monte Carlo was preferred according to its high accuracy because a number of photon packets can be launched to increase efficiency. Also Finite Difference Method was used for heat diffusion because of its simplicity. The results taken from Monte Carlo Model are used as a source term in heat conduction equation. Thus, in small time steps by doing iterations of Finite Difference Method thermal gradients are measured inside a tissue. At 1064 nm fluence and thermal contours of brain and liver tissues are obtained with same laser parameters. Also at different wavelengths, 1064 nm and 630 nm, fluence and thermal contours of liver tissue are calculated in the same conditions. Moreover, fluence and thermal contours of liver tissue are measured for different power densities and exposure times. The thermal gradients of laser irradiated tissue were plotted with 2D colored surface plotting.|Keywords: Monte Carlo Model, Finite Difference Method, light propagation, heat diffusion, Java.