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Objective:To explore the present state of radiation protection in an operational large-sized irradiation facility and the distribution of incurred radiation doses in the controlled area under abnormal conditions, and to analyze the acompanied radiation risk.Methods:With an irradiation facility in operation as the research object, the radiation doses were measured using AT1121 X and gamma dose rate meters for the soruce both in working and storage. Thermoluminescent dosimeters (TLDs) were used to measure the dose distribution in an irradiation field under abnormal conditions. The radiation safety features were checked against the several relevant national standards, with the radiation risks evaluated.Results:The radiation dose rates were in the range of 0.09-0.11 μSv/h, lower than the environmental background level whether in storage or working. Under abnormal working conditions, the radiation dose values from high to low were 1.0-101.3 Sv, 32.7-514.0 mSv and 8.7-183.2 μSv in the irradiation field, respectively. At the outside maze, the doses were close to the background level.Conclusions:The protection features of the irradiation facility meet the requirements of the relevant national standards. Under abnormal conditions, radiation could cause serious damages to the persons staying in the irradiation field. These persons were suggested to access to maze as soon as possible to reduce the exposure time, and activate the emergency protection equipments to deescalate the 60Co source onto the well.
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Objective:To monitor and analyze the activity concentrations of 7Be and 210Pb in atmospheric aerosol in Beijing from 2017 to 2020. Methods:Totally 1 074 atmospheric aerosol samples were collected by high flow air sampler (SnowWhite) including 275 in spring, 266 in summer, 262 in autumn and 271 in winter and subjected to analysis by low background high-purity germanium gamma-ray spectrometery (ORTEC) to determine the activity concentrations of 7Be and 210Pb. Results:The activity concentrations of 7Be in atmospheric aerosol were from 0.56 to 14.84 mBq/m 3, with an avearage of 6.84 mBq/m 3, and from 0.01 to 9.37 mBq/m 3 for 210Pb, with an avearage 3.19 mBq/m 3. The differences in activity concentrations of 7Be and 210Pb in atmospheric aerosol among differernt seasons were statistically significant ( F=32.66, 93.93, P<0.05). Activity concentration of 7Be was highest in spring, followed by autumn, and lowest in summer and winter. Activity concentration of 210Pb ranged from winter, autumn, spring to summer in descending order. Conclusions:The activity concentrations of 7Be and 210Pb in atmospheric aerosol in Beijing from 2017 to 2020 fluctated within the range of normal level.
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Objective To analyze the distribution status and agglomeration degree of radiological diagnosis and treatment resources in Beijing, and provide references for rationally coordinating the allocation of radiological diagnosis and treatment resources, formulating resource allocation policies, and promoting the stable development and efficient use of radiological diagnosis and treatment resources. Methods Based on the medical radiation protection monitoring data of Beijing medical and health institutions from 2019 to 2020, the current situation of radiological diagnosis and treatment resources is described by the number of radiological diagnosis and treatment resources, the average service volume, and the resource composition, and the distribution of radiological diagnosis and treatment resources in Beijing is evaluated with the aid of the agglomeration degree. Results The number of radiological diagnostic equipment, the number of service personnel, and the number of radiological workers engaged in third-level hospitals is the largest; for the number of service personnel for each type of single equipment, third-level hospitals account for a larger proportion, and radiotherapy and nuclear medicine services are concentrated in third-level hospitals. Human resource pressure and equipment service pressure are relatively high in third-level hospitals. First-level hospitals mainly undertake radiological diagnosis services. There is little difference in the amount of radiological diagnosis services per capita between second-level hospitals and third-level hospitals. Nuclear medicine and radiotherapy in third-level hospitals per capita service volume is significantly higher than that insecond-level hospitals. Radiological diagnosis and radiotherapy resources are concentrated in urban areas to a large extent. Conclusion There are obvious differences in the utilization of radiological diagnosis and treatment resources in different levels of hospitals. There is a significant concentration of radiological diagnosis and treatment resources in various districts. There is a certain degree of unbalanced distribution and inadequate utilization of radiological diagnosis and treatment resources in Beijing.