Monte Carlo simulation of radiation dose in human trafficking scenarios detected by cargo X-ray imaging systems

Abstract Introduction Cargo X-ray imaging systems are essential for security and customs inspections, using high-energy X-rays to detect contraband in large cargo containers. However, in human trafficking scenarios, individuals hidden inside these containers may be exposed to significant radiation doses. This study quantifies radiation doses absorbed by such individuals using Monte Carlo simulations with TOPAS, a Geant4-based toolkit. Methods A human phantom with selected radiosensitive organs was modelled in different positions within the container, and simulations were conducted using realistic conditions with X-ray energies of 4, 6, and 9 MeV, replicating the Linatron-Mi system. Equivalent dose rates for radiosensitive organs were calculated based on varying human positions and container wall materials. Results Radiation doses vary significantly depending on X-ray energy and human position. The highest doses occurred when the human phantom was directly behind the container wall, with equivalent doses approaching fractions of annual public dose limits. Shielding provided by cargo contents reduced the dose by up to 92%, but worst-case scenarios remain concerning. Conclusion These findings highlight the need for enhanced safety measures, including AI-driven detection systems to automatically terminate irradiation upon detecting human presence. This study underscores the importance of improving safety protocols in cargo imaging systems to minimize accidental exposure.