Method of simulating photon transport in inhomogeneous media by means of the voxel-by-voxel process

In this paper, we describe an algorithm for photon transport calculation, named the ''voxel-by-voxel process'', to be used in Monte Carlo simulation codes with inhomogeneous media in which various material regions exist. In the voxel-by-voxel process, phantoms were constructed by dividing the volume of a rectangular prism into tiny voxels of homogeneous media. The photon free path length and/or the electron range in the voxelized phantom could be calculated uniformly using the unit of the voxel. By means of this method, Monte Carlo simulation could be performed with intricate inhomogeneous media, and the standardized Monte Carlo code could be programmed. (author)