Shielding performance of six different types of concrete in proton therapy room / 中国辐射卫生

ABSTRACT

@#<b>Objective</b> To study the dose level of proton beams outside the main shield of the 230 MeV proton therapy room with six different types of concrete as the main wall, and to obtain the shielding performance of six different types of concrete. <b>Methods</b> The FLUKA program was used to build a calculation model, and different concrete compositions were introduced into the FLUKA program to simulate the change in ambient dose equivalent rate of the focus with concrete thickness under 230 MeV proton beam irradiation. The transmission curves of six different types of concrete were fitted to obtain shielding performance parameters. <b>Results</b> On the condition that the 230 MeV proton beam irradiated to the water target in 90° direction and the concrete thickness exceeded 40 cm, the proton beam was exponentially decayed for six different types of concrete, and the fitted decay curves had a <i>R</i>² of > 0.99. The linear attenuation coefficients for normal concrete, barite concrete, magnetite concrete, limonite concrete, phosphorite concrete, and ferrosilicate concrete were 0.0148 cm⁻¹, 0.0172 cm⁻¹, 0.0196 cm⁻¹, 0.0219 cm⁻¹, 0.0256 cm⁻¹, and 0.0290 cm⁻¹, respectively. <b>Conclusion</b> The composition and proportion of elements in concrete materials directly affect the shielding ability of concrete against proton beams to a large extent, and the shielding performance of six different types of concrete against proton beams varies greatly. Therefore, shielding materials for the proton therapy room should be selected by a comprehensive consideration of the material compositions and shielding performance of concrete, the difficulty of construction, and construction cost.