Design and shielding effectiveness of adjustable modular medical radiation shelter

Medical imaging and radiotherapy rely on ionizing radiation that must be contained to protect staff, patients, and the public. Conventional shielding rooms use permanent, immobile concrete walls that are slow to build, leaving primary clinics and emergency sites poorly served. A modular, adjustable shelter was designed with six-sided composite walls combining barite-paraffin, a 24-cm water layer, and 0.5-20-mm lead plates for synergistic photon and neutron shielding, with S/Z-shaped penetrations to suppress joint leakage. Per the Chinese diagnostic radiology standard GBZ 130-2020, analytical models predicted shielding of 70-150 kVp diagnostic X-rays and 6 MV photons and an 11.9-fold reduction of 2 MeV neutrons. Geant4 Monte Carlo validation across six clinical scenarios (39 keV-1.47 MeV photons, 2 MeV neutrons) reproduced the model within 2.5% at 511 keV; exterior ambient dose equivalent H*(10) remained below 0.5 μSv h-1, satisfying the GBZ 130-2020 public dose limit. The shelter provides flexible, rapidly deployable protection for routine and emergency medical use.