The shielding design of distributed X-ray tube

<bold>Background</bold>Different from traditional single-focus X-ray tubes, distributed X-ray tubes with multiple focal spots require targeted research on radiation protection and shielding design.<bold>Purpose</bold>This study aims to design and validate an effective shielding structure for distributed X-ray tube with uniform thickness to ensure radiation safety.<bold>Methods</bold>Firstly, Monte Carlo simulation was performed to analyze the radiation field characteristics of a 45-focal-spot distributed X-ray tube operating at 160 kV anode voltage and 15 mA anode current. Then, the leakage dose rates were calculated for lead shielding thicknesses ranging from 1 mm to 6 mm on all shielding surfaces. Finally, a shielding structure with uniform thickness of 5~6 mm on each surface was designed and assembled with the X-ray tube for experimental validation.<bold>Results</bold>The simulation results show that the distributed X-ray source exhibits line-source characteristics. The designed shielding structure with uniform thickness of 5~6 mm lead on each surface achieves leakage dose rates below 5 μGy·h^-1 at all measurement points. The deviation between simulation and actual measurements is consistently below 25%, with most measured values being lower than simulated ones. The highest leakage rates of 2.4 μGy·h^-1 and 2.92 μGy·h^-1 occur at the front lower middle and rear lower middle positions, respectively, which is consistent with the line-source characteristics and reflection target structure.<bold>Conclusions</bold>The uniform thickness shielding design proposed in this study is feasible and effective for distributed X-ray tubes. The Monte Carlo simulation method can reliably guide the shielding structure design, and all measurement points meet the radiation protection requirement of leakage dose rate below 5 μGy·h^-1.