Paper #3

Monte Carlo Simulation of Cone X-ray Beam and Dose Scoring on Voxel Phantom with Open Source Software EGSnrcmp

Nikolaos Chatzisavvas, Dimitrios Nikolopoulos, Georgios Priniotakis, Ioannis Valais, Thanasis Koustas and Georgios Karpetas

Abstract: Radiation is used nowadays for inspection, therapy, food safety, and diagnostic purposes. Our daily lives include the use of devices like airport scanners, projectional radiographers, CT scanners, treatment heads, cargo inspection systems, etc. However, these systems are extremely complicated and cost a significant amount of money to study, maintain and conduct research with. Monte Carlo is the ideal method for simulating such systems successfully and achieving findings that are remarkably comparable to experimental methods. Simulation software, however, is not always free, open source, and accessible to everyone. Open source software has gained popularity in the technological age that best represents the period we are living in, and practically all significant software sectors now use open source software tools. With the aid of an open-source, thoroughly validated software, called EGSnrcmp we were able to describe an abstract model-geometry of a cone-beam computed tomography X-rays source, produce patient-specific phantoms and score dosage values based on characteristics of the cone beam source. We outline the necessary methods and provide useful details about how to conduct such studies inside the software's ecosystem. Our study focuses on the relationship between the cone-beam source's field of view (FOV) and its impact on patient dosage, by emulating a CBCT examination. To characterize our cbct source, we employed stainless steel material to build the collimator and tungsten (W) material to build the anode. The most frequent energy at which these tests are conducted is 100 keV, which is the energy of the electrons we utilize. We were able to score absorbed dosage within a phantom produced from dicom images of a real patient, demonstrate the relationship between the FOV of the beam and the absorbed dosage and verify the cbct source using theoretical values.

Keywords: Medical Imaging; Monte Carlo; Open-source; Simulation; Software; Spectral distribution.