Objective To verify the radiation shielding effects of a self-developed protective shield for infant bedside X-ray radiography, and measure the dose distribution in the indoor radiation field with and without the shield, and to provide guidance for the radiation protection of infants sharing the room. Methods A MUX-100J mobile medical diagnostic X-ray machine was used as the radiographic device to simulate the exposure conditions of infant bedside X-ray radiography. The ambient dose equivalent rates at measurement points in eight directions on the irradiation plane in the indoor radiation field were measured with and without the protective shield using an AT1121 X/γ dose rate meter under the conventional condition of 56 kV and the maximum single exposure time. Results During infant bedside X-ray radiography, the dose levels in all directions on the irradiation plane within 150 cm from the scatterer center were essentially symmetrically distributed. The ambient dose equivalent rate at 100 cm from the scatterer center on the irradiation plane was (8.01-8.28)×10³ μSv/h without the protective shield and 48-84 μSv/h with the shield. At various distances from the scatterer center in all directions on the irradiation plane, the doses measured with the protective shield ranged from 0.34% to 14.12% of those measured without the shield, with an average of 1.85%. Conclusion The dose levels in the indoor radiation field were significantly reduced with the protective shield during infant bedside X-ray radiography. The use of the protective shield can effectively reduce the radiation risk for individuals near the radiographic site within the same room.

Objective To verify the radiation shielding effects of a self-developed protective shield for infant bedside X-ray radiography, and measure the dose distribution in the indoor radiation field with and without the shield, and to provide guidance for the radiation protection of infants sharing the room. Methods A MUX-100J mobile medical diagnostic X-ray machine was used as the radiographic device to simulate the exposure conditions of infant bedside X-ray radiography. The ambient dose equivalent rates at measurement points in eight directions on the irradiation plane in the indoor radiation field were measured with and without the protective shield using an AT1121 X/γ dose rate meter under the conventional condition of 56 kV and the maximum single exposure time. Results During infant bedside X-ray radiography, the dose levels in all directions on the irradiation plane within 150 cm from the scatterer center were essentially symmetrically distributed. The ambient dose equivalent rate at 100 cm from the scatterer center on the irradiation plane was (8.01-8.28)×10³ μSv/h without the protective shield and 48-84 μSv/h with the shield. At various distances from the scatterer center in all directions on the irradiation plane, the doses measured with the protective shield ranged from 0.34% to 14.12% of those measured without the shield, with an average of 1.85%. Conclusion The dose levels in the indoor radiation field were significantly reduced with the protective shield during infant bedside X-ray radiography. The use of the protective shield can effectively reduce the radiation risk for individuals near the radiographic site within the same room.

Objective To verify the radiation shielding effects of a self-developed protective shield for infant bedside X-ray radiography, and measure the dose distribution in the indoor radiation field with and without the shield, and to provide guidance for the radiation protection of infants sharing the room. Methods A MUX-100J mobile medical diagnostic X-ray machine was used as the radiographic device to simulate the exposure conditions of infant bedside X-ray radiography. The ambient dose equivalent rates at measurement points in eight directions on the irradiation plane in the indoor radiation field were measured with and without the protective shield using an AT1121 X/γ dose rate meter under the conventional condition of 56 kV and the maximum single exposure time. Results During infant bedside X-ray radiography, the dose levels in all directions on the irradiation plane within 150 cm from the scatterer center were essentially symmetrically distributed. The ambient dose equivalent rate at 100 cm from the scatterer center on the irradiation plane was (8.01-8.28)×10³ μSv/h without the protective shield and 48-84 μSv/h with the shield. At various distances from the scatterer center in all directions on the irradiation plane, the doses measured with the protective shield ranged from 0.34% to 14.12% of those measured without the shield, with an average of 1.85%. Conclusion The dose levels in the indoor radiation field were significantly reduced with the protective shield during infant bedside X-ray radiography. The use of the protective shield can effectively reduce the radiation risk for individuals near the radiographic site within the same room.

Objective To analyze the implementation status of GBZ 130-2020 Requirements for Radiological Protection in Diagnostic Radiology in Beijing City and identify the problems in standard implementation. Methods A total of 222 professionals from 127 medical institutions, radiation health technical service institutions and health supervision institutions in Beijing City were selected as the study participants using the stratified random sampling method. Standard Implementation Evaluation Questionnaire was used to assess their evaluations on the standard technical content, implementation status and implementation effectiveness. Radiation protection inspection reports were reviewed to obtain data on external dose level outside shielding from 8 810 radiological diagnostic rooms in Beijing City. Technical risk points in standard implementation were identified through discussion with the experts and qualitatively analyzed. Results The measurement score for standard implementation was 95.1. The scores for the first-level indicators of standard technical content, standard implementation status, standard implementation effectiveness were 39.0, 26.2 and 29.9, respectively. Among the second-level indicators, standard publicity and training scored the lowest at 7.6. A total of 17 major problems related to standard implementation were identified, including inconsistent dose limits around imaging rooms versus environmental protection limits, absence of protection requirements for new equipment such as vehicle-mounted compated tomograph (CT) and CT shelter, and poor compliance with dental protective devices. The overall pass rate for external dose level outside shielding among radiological diagnostic rooms in Beijing City was 99.6%. Among the 40 non-compliant rooms, structural defects such as improper door/window overlaps accounted for 52.5%. Conclusion The implementation of GBZ 130-2020 Requirements for Radiological Protection in Diagnostic Radiology in Beijing City is generally good, with improved standardization level of radiation protection. However, there remain rooms for optimization in indicator coordination and standard publicity and training.

Objective To analyze the layout and shielding effectiveness of medical accelerator vaults, and to provide a reference for the layout, shielding design, and optimization of protection of medical accelerator vaults. Methods Four medical accelerator radiotherapy vaults were selected. The layouts of these vaults were compared with the layout requirements in the radiation therapy protection standards. For each vault, the dose rates at four points of interest outside the shielding were calculated, including the primary shielding area, secondary shielding area, maze outer wall, and lateral shielding area. These values were then compared with the actual measurements obtained using a dose rate meter. Results All four vaults were located on the ground floor of the building and included a maze, with the auxiliary rooms all placed outside the treatment rooms. However, one vault was not located at one end of the building, and in another vault, the control room was exposed to direct irradiation of the useful beam. The calculated dose rates outside the primary shielding area ranged from 0.04 μSv/h to 0.62 μSv/h, while the measured values ranged from 0.10 μSv/h to 0.66 μSv/h, with the measured values being higher than the calculated ones. The calculated dose rates outside the secondary shielding area ranged from 0.0005 μSv/h to 0.12 μSv/h, those outside the maze outer wall ranged from 0.06 μSv/h to 0.18 μSv/h, and those outside the lateral shielding area ranged from 0.009 μSv/h to 0.15 μSv/h; the measured values were all below the detection limit. Conclusion Inadequate layouts were observed in some of the accelerator vaults. The calculated and measured dose rates at points of interest outside the vaults were both significantly lower than the shielding protection requirements in standards, indicating that the shielding designs were overly conservative. Construction units should follow the principle of optimization of radiation protection to design the layout and shielding reasonably and pay attention to the underestimation of dose rates outside the primary shielding caused by the tenth value layer.

Objective:To formulate refined management strategies to improve the operation quality and protective effect of medical X-ray diagnosis equipment based on the risk analysis of the correlation of medical X-ray diagnostic equipment.Methods:The used 41 medical X-ray diagnosis equipment in Fuwai Hospital,Chinese Academy of Medical Sciences from January 2022 to December 2023 were selected.According to different management modes for equipment,they were managed respectively by the conventional management mode(20 units)and the management mode with risk analysis of the correlation(21 units).The risk grades of correlation of management mode with risk analysis of the correlation were classified on the basis of the probability of risk and the degree of harm in medical X-ray diagnosis equipment.The protection management of equipment was conducted from three aspects included the location of equipment,the staffs and subjects.A self-made questionnaire was used to investigate the satisfactions of engineers of using management for equipment,operators,and staffs of operating and maintaining equipment for the two kinds of management modes.The protection quality,failure rate of equipment,and qualification rate of protection of medical X-ray diagnosis equipment under different management modes were compared.Results:The quality scores of operation safety,regular inspection,maintenance and repair,and shielding protection for radiation of medical X-ray diagnosis equipment that adopted the management mode with risk analysis of the correlation were respectively(92.14±3.36),(91.47±2.41),(92.54±3.32)and(91.69±3.57)points,all of which were higher than those of the conventional management mode,and the differences of them were statistically significant(t=16.396,17.368,19.688,14.401,P<0.05).The failure rate of the 21 medical X-ray diagnosis equipment that adopted the management mode with risk analysis of correlation was 0,which was lower than 20.00%of the conventional management mode.The qualified rate of protection was 95.23%,which was higher than 70.00%of the conventional management mode,and the differences of them were statistically significant(x2=4.654,4.608,P<0.05).The satisfaction scores of engineers of using equipment,operators and staffs of operating and maintaining equipment for the protective effect of adopting the management mode with risk analysis of correlation were respectively(94.69±4.02),(93.21±4.36)and(92.54±3.47)points,all of which were higher than those of the conventional management mode,and the differences were statistically significant(t=16.902,11.291,12.020,P<0.05).Conclusion:The process-based protection management strategy on the basis of risk analysis of correlation for medical X-ray diagnosis equipment can prevent risks of medical X-ray diagnostic equipment,and improve the operation quality of the equipment,and reduce the operation risks of the equipment,and maximize the enhancement for management quality of medical X-ray diagnosis equipment.

Objective To investigate the annual effective doses to radiation workers caused by radon concentrations in the underground workplaces of medical institutions, and to provide a scientific basis for the prevention and control of indoor radon in underground places. Methods A typical sampling method was used to select 5-30 medical institutions in each of Hunan, Jiangxi, Guizhou, Hubei, and Sichuan provinces. A total of 66 monitoring points in 66 medical institutions were selected. The indoor radon concentrations in underground workplaces were measured cumulatively using CR-39 solid nuclear track detectors. The radiation dose to radiation workers was estimated according to the method outlined in the Requirements for control of indoor radon and its progeny (GB/T 16146—2015). The Kruskal-Wallis H test was used to compare the differences in indoor radon concentrations between different provinces. Results The average indoor radon concentration in the underground workplaces of 66 medical institutions was 69.8 Bq/m³, with the highest being 147.6 Bq/m³. The average indoor radon concentrations in the underground workplaces of medical institutions in Sichuan, Guizhou, Hubei, Jiangxi, and Hunan were 72.1, 83.2, 66.6, 88.4, and 61.5 Bq/m³, respectively. The annual effective doses to radiation workers caused by radon concentrations in underground workplaces were 0.57-0.83 mSv, with an average of 0.69 mSv. There was a significant difference in radon concentrations among provinces (P < 0.05). Conclusion The indoor radon concentrations and personnel exposure doses in the underground workplaces of monitored medical institutions comply with national control standards. However, continuous monitoring and necessary indoor radon prevention and control measures are still needed.

Objective To establish typical values for interventional diagnosis and treatment at our institution, use these values as a tool to evaluate patient medical exposure doses, and optimize radiation protection measures. Methods From June to December 2023, we collected information on 593 adult cardiovascular interventional diagnosis and treatment surgeries, including surgery type, equipment model, air kerma-area product (KAP), incident reference point air kerma (K_a,r), perspective time (FT), and exposure mode. Results The typical value of cardiovascular interventional diagnosis at our institution in 2023 was 27.5 Gy·cm². The typical value of cardiovascular interventional treatment was 70.0 Gy·cm². The FT, KAP, and K_a,r of interventional surgeries were significantly higher than those of interventional diagnosis (P < 0.01). There were significant correlations between FT, KAP, and K_a,r (P < 0.01). Conclusion The results of this study were slightly different from those of other studies. They provide typical data and reference values for cardiovascular interventional diagnosis and treatment dose levels in Beijing and are helpful for dose optimization between different medical institutions.

Objective To evaluate the current status in the implementation of GBZ/T 201.5-2015 Radiation shielding requirements for radiotherapy rooms-Part 5: Radiotherapy room of proton accelerators, identify issues in the application of its technical indicators, and provide a basis for the in-depth implementation and further revision of the standard. Methods In accordance with the Standardization Law of the People’s Republic of China and the Guidelines for Health Standards Tracking Evaluation (WS/T 536-2017), a combination of cluster sampling and stratified sampling methods was employed to select professionals involved in proton accelerator radiotherapy devices and facilities in three provinces (or municipalities directly under the central government) as the subjects of the survey. A questionnaire was developed to collect basic information about the subjects and their understanding and application of the technical indicators in the standard. A standard evaluation indicator system with a total score of 100 points was established to score the implementation of the standard (40 points), the technical content (30 points), and the effectiveness of the implementation (30 points). Results A total of 169 professionals from 107 institutions participated in the survey, with 79.88% of the respondents having at least 5 years of experience in radiation therapy and 74.56% holding intermediate or higher professional titles. The score of standard implementation was 18.3 points. The awareness rate exceeded 80%, indicating a high level of awareness about the standard. However, the scores for the dissemination and application of the standard were relatively low, accounting for 28% and 32% of their respective full marks. The technical content of the standard and the effectiveness of its implementation scored 27.0 and 26.6 points, respectively. The overall score in the evaluation of standard implementation was 72 points, with scores of 68.6, 72.3, and 75.0 for Beijing City, Shanghai City, and Jiangsu Province, respectively. Conclusion GBZ/T 201.5-2015 Radiation shielding requirements for radiotherapy rooms-Part 5: Radiotherapy room of proton accelerators is scientific and operable, and it is well-coordinated with relevant laws and standards. However, considering the development in FLASH technology and multi-chamber radiotherapy room, it is necessary to revise and improve the standard.

Objective To track and evaluate the implementation and application of the occupational health standard Radiation shielding requirements for radiotherapy room—Part 4: Radiotherapy room of ²⁵²Cf neutron afterloading (GBZ/T 201.4-2015) by radiation health technical service agencies, medical institutions, health supervision agencies, and radiotherapy facility design units, and to provide a scientific basis for the further revision and implementation of this standard. Methods Following the Guideline for health standards tracking evaluation (WS/T 536-2017) and the project implementation plan, relevant practitioners were randomly selected for a questionnaire survey. The survey primarily focused on their awareness, standard training, application, and revision suggestions of GBZ/T 201.4-2015. The results were summarized and analyzed. Results A total of 168 evaluation questionnaires were collected from relevant practitioners in 28 provinces. Only 31.6% of the respondents reported being “well familiar” or “ familiar” with the standard, 27.4% of the respondents believed that the standard was widely used, and 45.2% of the respondents believed that the standard could meet the needs of their work. Only 14.9% of the respondents had received relevant training on the standard, more than half of the respondents had not applied the standard within the past 10 years, and 45.2% of the respondents believed that the standard "needs to be revised". Conclusion Due to the small number of californium-252 neutron afterloading radiotherapy devices in operation on the market, the overall awareness of the standard is low, suggesting that relevant authorities need to strengthen training and publicity of the standard, and that certain sections of the standard need to be revised or merged.