A Monte Carlo Platform for Characterization of X-Ray Radiation Dose in CT Imaging

Background: Computed tomography (CT) is currently known as a versatile imaging tool in the clinic used for almost all types of cancers. The major issue of CT is the health risk, belonging to Xray radiation exposure. Concerning this, Monte Carlo (MC) simulation is recognized as a key computational technique for estimating and optimizing radiation dose. CT simulation with MCNP/MCNPX MC code has an inherent problem due to the lack of a fanbeam shaped source model. This limitation increases the run time and highly decreases the number of photons passing the body or phantom. Recently, a beta version of MCNP code called MCNP-FBSM (FanBeam Source Model) has been developed to pave the simulation way of CT imaging procedure, removing the need of the collimator. This is a new code, which needs to be validated in all aspects. Objective: In this work, we aimed to develop and validate an efficient computational platform based on modified MCNP-FBSM for CT dosimetry purposes.Material and Methods: In this experimental study, a setup is carried out to measure CTDI100 in air and standard dosimetry phantoms. The accuracy of the developed MC CT simulator results has been widely benchmarked through comparison with our measured data, UK’s National Health Service’s reports (known as ImPACT), manufacturer’s data, and other published results. Results: The minimum and maximum observed mean differences of our simulation results and other abovementioned data were the 1.5%, and 9.79%, respectively. Conclusion: The developed FBSM MC computational platform is a beneficial tool for CT dosimetry.