PET reconstruction system matrix

DLL to generate a PET system matrix for image reconstruction

This include a MEX-DLL file which is an implementation of R L Siddon's refined method by Jacob for the calculation of ray path integral in PET/CT system image reconstruction. This is based on Line Intersection Length model to calculate probability matrix elements. Inputs are the LOR number and a structure defining the system geometry such as pixel numbers and widths. Help is included on use in a file SYS_MAT.m or the CPP file.