Quantitative Assessment of Scattering Contributions in MeV-Industrial X-Ray Computed Tomography

Scattering of high energetic X-ray photons causes artifacts in industrial computed tomography (CT). In particular, for MeV photons, the interaction cross-sections for scattering processes dominate those of the photoelectric effect. In addition, electron-positron pair formation is enabled. In this paper, the effect of scattering processes on the deposited energy in a line detector is examined as a model for a transmission image. To distinguish contributions from different interaction processes, Monte Carlo simulations are performed based on the GEANT4 framework. This study focuses on simplified models of the system and primitive objects in particular boxes to determine the generic behavior of scattered radiation. Our results indicate that with the help of detector collimation a reduction of the scattering contribution up to a factor of two can be achieved.