Monte Carlo simulation of phase-contrast X-ray imaging with a single-grid setup

Phase-contrast X-ray imaging is widely used to visualize the internal structures of samples that cannot be seen with conventional X-ray imaging. Among various phase-sensitive imaging techniques available—propagation-based, grating-interferometry, edge-illumination, and speckle-based—single-grid-based imaging, a variant of the speckle-based technique, provides benefits like single exposure and a simple setup. In this study, we developed a Monte Carlo (MC) simulator based on Geant4 for phase-contrast imaging with a single-grid setup. We then validated the MC simulations of single-grid imaging against theoretical predictions. Our results demonstrate that the phase-contrast images obtained using the simulator align well with the theoretical predictions. Moreover, we quantitatively investigated the effects of imaging parameters, such as X-ray focal spot size and grid period, on image quality using the MC simulator. This confirmed the viability of the simulator. We expect that this simulator will be useful in designing an optimal single-grid-based imaging setup.