Development of a GUI to acquire EPID images and get energy fluence in a binary phase space file as input to the Monte Carlo EGSnrc simulation software

The Monte Carlo method provides approximate solutions in medical physics with high precision. The Monte Carlo EGSnrc software with its DOSXYXnrc routine can simulate physical phenomena in clinical linear particle accelerators associated with radiotherapy. A graphical user interface was developed in MATLAB to get a binary phase space file in EGSnrc format with information on the energy fluence of the ELEKTA AXESSE linac with energy of 6 MV., as input from source number two of the DOSXYZnrc routine, for dose reconstruction on homogeneous and inhomogeneous analytical phantoms. From EPID, portal images of an IMRT plan are acquired, they are subjected to different corrections for gray values, sensitivity variation in planar array detectors and transmission in multi-leaf collimators. The corrected images are calibrated at portal dose and energy fluence is get with a deconvolution kernel, its parameter previously fit. Energy fluence is used to sample the phase space and get the binary file. (author)