Objective To understand the radiation level of X-ray luggage inspection systems in the subway stations of Songjiang District of Shanghai, and to provide basic data for strengthening radiation protection management in subway stations.
Methods Nine subway stations in Songjiang District involving 16 X-ray luggage inspection systems were included in the study. The air kerma rate around multiple positions 0.05 m away from the system surface were measured to analyze and evaluate the surrounding radiation doses.
Results There were no significant differences between the environmental background values and the monitoring values of staff operating position, passenger channel, and the upper cover and passenger channel side of the X-ray luggage inspection systems (P>0.05). The median air kerma rates at system inlet (1.291 μGy/h) and outlet (0.248 μGy/h) were all significantly higher than the environmental background value (P<0.01), but less than the national limit of 5 μGy/h. Of all the 16 machines, the air kerma rates of 8 monitoring points from 4 machines were higher than the standard (> 5 μGy/h). After excluding the machines exceeding national standards, the average radiation doses of inlet and outlet still showed significantly higher values than the environmental background value, with the lower position of the inlet showing the highest followed by the intermediate position (P<0.01).
Conclusion Radiation leaks exist but pose little health effects to the public and subway staff. It is suggested, therefore, that radiation protection management of X-ray luggage inspection systems in subway stations should be further strengthened.
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