Geant4 simulation and XCOM theory in CT contrast agents mass attenuation coefficient research

Contrast agents play a crucial role in medical imaging by enhancing the absorption and scattering of photons in target tissues. Radiologists need to understand the attenuation characteristics of contrast agents to make accurate diagnoses. In this study, we focused on the mass attenuation coefficients of ioversol (C18H24I3N3O9) and barium sulfate (BaSO4), which are widely used in computed tomography (CT) imaging. We employed Geant4, a Monte Carlo particle transport simulation tool, to calculate the mass attenuation coefficients of these contrast agents across the energy range of 20 keV to 70 keV. The simulated values were compared with theoretical results obtained from the XCOM program. The results showed that the mass attenuation coefficients of iodixanol and barium sulfate exhibited a trend of increasing initially, and then sharply increases at the absorption edge before decreasing again. This trend is consistent with the absorption edge of iodine at 33.1 keV. The comparison between the Geant4 simulations and the XCOM program results revealed a small deviation, with the maximum difference being less than 0.05. Our study demonstrates the feasibility and accuracy of using Geant4 simulations to study the mass attenuation coefficients of CT contrast agents. The findings provide valuable insights for optimizing CT imaging techniques and improving contrast agent design. Future research may involve further optimization of simulation parameters and exploration of mass attenuation coefficients for other contrast agents to support the development of medical imaging.