Time Dependent Monte Carlo (TDMC) Simulation Data Output for Photon-Tissue Interactions

Abstract

Timedependent (TD) Monte Carlo (TDMC) photon-tissue interactions simulation programcode generated photon fluencies (Joule/cm²) for ten picosecond (ps) time series[100 , 200,  … 1000] for Continuous Wave(CW) laser source. TD MC ANSI Standard C program code “trmc.c” was modified andcompiled to generate photon fluence distributions inside the imaging tissuemodel. Cylindrical coordinate system was chosen to compile the ANSI standard Cbased photon walk program code. Radial r, and depth z axis created cylindricalmesh grid (r, z) array. Collimated isotropic point laser source within asemi-infinite homogeneous medium was used. Radial diameter of cylindricalcoordinate system 2r = 6.0 cm, depth z = 3.0 cm. In this study, TD analysis ofCW MC photon fluencies for the photon-tissue interactions simulation mesh gridgeometry for Nz = 30, and Nr = 30 dimensions within 3 cm x 6 cm was performed.In the MC simulation program code, the tissue absorption and scatteringcoefficients were chosen as a = 0, and s = 100 cm-1.60.000 photons were sent into the tissue from (x, y, z) = (3.0, 3.0, 3.0) cmisotropic laser source position. The values of photon fluencies are varyingdepend on the time in tissue environment were recorded in the ANSI standard Cprogram data output file. The time intervals were chosen by 100 picosecond (ps)steps, from 100 ps to 1000 ps sequentially. Depend on the increasing timesteps, CW photon migration was observed inside the tissue, successfully. TDanalysis of CW photon fluencies will be used when making the time resolveddiffuse optic tomography (TRDOT) device. Forward model problem weight matrixwill be built based on the TD distributions of MC photon fluencies, then photonfluencies will be used in the inverse problem solution image reconstructionalgorithm. The location of buried inclusions will be determined.