Geant4 modeling and experimental validation of a BGO-based indirect X-ray imaging system: Toward optimized performance

This work investigates the performance of an indirect X-ray imaging system based on a scintillator detector. We develop and validate a Geant4-based simulation tool that models the X-ray interactions, energy deposition, and the generation and transport of scintillation photons within a Bismuth Germinate Oxide (BGO) scintillator. The model is validated by comparing simulated and experimentally measured Point Spread Functions (PSFs) using a laboratory X-ray imaging system, showing excellent agreement. To illustrate its capability, the validated model is then used to investigate the influence of key parameters such as scintillator thickness, surface reflectivity, and source cone angle on imaging performance. These results highlight the trade-offs between detection efficiency, contrast, and spatial resolution, providing valuable guidelines for the optimization of scintillator-based X-ray imaging systems.