Objective:To investigate the radiation dose levels of digital radiography (DR) in adult patients and explore the diagnostic reference level (DRL) of radiation dose in Beijing.Methods:Radiation dose data were collected from 39 medical institutions in Beijing on 18 930 DR examinations of chest anterior and lateral view, abdomen anterior and posterior view, abdomen standing view, cervical spine anterior and lateral view, lumbar spine anterior and lateral view, knee joint anterior and lateral view as well as 5 266 digital mammography (CC view and MLO view). For ordinary DR examinations, the incident air kinetic energy ( Ka, i), incident air specific kinetic energy area product ( PKA) and effective dose ( E) to the examined individuals were used for the investigation and estimation of radiation dose. For digital mammography, the average glandular dose (AGD) was calculated. DRLs should be set at the 75 th percentile of median values obtained in each medical institution. Results:The Ka, i, PKA and E of DRL for Chest (PA), Chest (lateral), abdominal(PA), abdominal (AP), Pelvic(AP), Cervical (AP), Cervical (lateral), Lumbar (AP), Lumbar (lateral), Knee joint (AP) and Knee joint (lateral) of conventional DR were 0.14, 0.31, 1.25, 2.18, 1.86, 0.51, 0.14, 2.97, 8.39, 0.37, 0.37 mGy, 159, 259, 1 917, 2 336, 2 867, 312, 301, 3 500, 3 359, 269, 255 mGy·cm 2, 0.03, 0.05, 0.20, 0.43, 0.23, 0.03, 0.02, 0.47, 0.35, <0.001, <0.001 mSv. The DRLs for digital mammography were calculated to be 1.87 mGy (CC view), 1.94 mGy (MLO view) and 3.99 mGy (accumulated for one examination). Conclusions:The radiation dose from DR examinations is relatively low. In clinical practice, the selection of imaging parameters should be further standardized on the basis of the local DRL.

With advancements in interventional radiology, the interventional diagnosis and treatment are widely applicable for pediatric cardiac diseases. The ionizing radiation during interventional procedures can result in an elevated cancer risk, directly proportional to the radiation dose received. Moreover, it may induce tissue reactions beyond a specific threshold. Given that children are about 2-3 times susceptible to radiation as much as adults, it will be crucial to improve dose control during pediatric interventions, establish the corresponding diagnostic reference level and optimize the diagnosis and treatment procedures. Some countries have carried out dose monitoring and evaluation of pediatric cardiac interventional procedures and established corresponding diagnostic reference levels, but it has yet been in the process of research. This paper reviews the current research status on assessing radiation doses and setting diagnostic reference levels for children receiving congenital heart disease interventions so as to provide a baseline for future measurements and investigations.

Objective:To measure and estimate the radiation dose to breast cone-beam CT (CBCT) -scanned examinees, which can provide a dose reference for the selection of mammography equipment in the clinic.Methods:In this study, using a 400 cm 3 Alderson radiation therapy (ART) breast phantom and thermoluminescent detectors (TLDs), the distribution of absorbed dose, and the average glandular dose (AGD), to the examined breasts caused by a breast CBCT scanner was measured and calculated scanner at 50 and 100 mA tube currents. Results:At 50 and 100 mA tube currents, the range of breast absorbed dose inside the examined breast measured based on the phantom was 2.25-7.97 mGy and 3.88-15.68 mGy, respectively, with breast absorbed dose decreasing from the periphery to the centre of the phantom, and the related AGDs were 4.87 and 9.81 mGy, respectively.Conclusions:The AGDs to the breast of CBCT-scanned examinees measured in this study was higher than in the case of commonly used digital mammography. This will be meaningful to provide the guidance on the rational choice of imaging equipment in future clinical practice.

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 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.

Objective:To investigate the radiation dose levels of digital radiography (DR) in adult patients and explore the diagnostic reference level (DRL) of radiation dose in Beijing.Methods:Radiation dose data were collected from 39 medical institutions in Beijing on 18 930 DR examinations of chest anterior and lateral view, abdomen anterior and posterior view, abdomen standing view, cervical spine anterior and lateral view, lumbar spine anterior and lateral view, knee joint anterior and lateral view as well as 5 266 digital mammography (CC view and MLO view). For ordinary DR examinations, the incident air kinetic energy ( Ka, i), incident air specific kinetic energy area product ( PKA) and effective dose ( E) to the examined individuals were used for the investigation and estimation of radiation dose. For digital mammography, the average glandular dose (AGD) was calculated. DRLs should be set at the 75 th percentile of median values obtained in each medical institution. Results:The Ka, i, PKA and E of DRL for Chest (PA), Chest (lateral), abdominal(PA), abdominal (AP), Pelvic(AP), Cervical (AP), Cervical (lateral), Lumbar (AP), Lumbar (lateral), Knee joint (AP) and Knee joint (lateral) of conventional DR were 0.14, 0.31, 1.25, 2.18, 1.86, 0.51, 0.14, 2.97, 8.39, 0.37, 0.37 mGy, 159, 259, 1 917, 2 336, 2 867, 312, 301, 3 500, 3 359, 269, 255 mGy·cm 2, 0.03, 0.05, 0.20, 0.43, 0.23, 0.03, 0.02, 0.47, 0.35, <0.001, <0.001 mSv. The DRLs for digital mammography were calculated to be 1.87 mGy (CC view), 1.94 mGy (MLO view) and 3.99 mGy (accumulated for one examination). Conclusions:The radiation dose from DR examinations is relatively low. In clinical practice, the selection of imaging parameters should be further standardized on the basis of the local DRL.

With advancements in interventional radiology, the interventional diagnosis and treatment are widely applicable for pediatric cardiac diseases. The ionizing radiation during interventional procedures can result in an elevated cancer risk, directly proportional to the radiation dose received. Moreover, it may induce tissue reactions beyond a specific threshold. Given that children are about 2-3 times susceptible to radiation as much as adults, it will be crucial to improve dose control during pediatric interventions, establish the corresponding diagnostic reference level and optimize the diagnosis and treatment procedures. Some countries have carried out dose monitoring and evaluation of pediatric cardiac interventional procedures and established corresponding diagnostic reference levels, but it has yet been in the process of research. This paper reviews the current research status on assessing radiation doses and setting diagnostic reference levels for children receiving congenital heart disease interventions so as to provide a baseline for future measurements and investigations.

Objective:To measure and estimate the radiation dose to breast cone-beam CT (CBCT) -scanned examinees, which can provide a dose reference for the selection of mammography equipment in the clinic.Methods:In this study, using a 400 cm 3 Alderson radiation therapy (ART) breast phantom and thermoluminescent detectors (TLDs), the distribution of absorbed dose, and the average glandular dose (AGD), to the examined breasts caused by a breast CBCT scanner was measured and calculated scanner at 50 and 100 mA tube currents. Results:At 50 and 100 mA tube currents, the range of breast absorbed dose inside the examined breast measured based on the phantom was 2.25-7.97 mGy and 3.88-15.68 mGy, respectively, with breast absorbed dose decreasing from the periphery to the centre of the phantom, and the related AGDs were 4.87 and 9.81 mGy, respectively.Conclusions:The AGDs to the breast of CBCT-scanned examinees measured in this study was higher than in the case of commonly used digital mammography. This will be meaningful to provide the guidance on the rational choice of imaging equipment in future clinical practice.

Objective To evaluate the ambient dose equivalent rates of photons and neutrons inside and outside the door of a 10 MV accelerator room, and to report the shielding effect of boron-containing polyethylene as maze wall lining. Methods The ambient dose equivalent rates of photons and neutrons inside and outside the door of an accelerator room were taken as the research subject. The Kersey, Falcão, and modified Kersey methods were used to calculate the ambient dose equivalent rates of neutrons and neutron capture gamma rays inside and outside the door of the room before and after renovation. Measurements were made using an X-ray/γ-ray dose rate instrument and a neutron ambient dose equivalent rate meter. Calculated and measured results were compared. Results Before renovation, the measured neutron dose rate inside the door was 409 μSv/h, while the calculated values were 323 μSv/h (Kersey method), 428 μSv/h (Falcão method), and 219 μSv/h (modified Kersey method). The Falcão method yielded a value closest to the measured value, while the Kersey and the modified Kersey methods underestimated the value by 21% and 46%, respectively. After the installation of boron-containing polyethylene plates, the measured neutron dose rate inside the door was 190 μSv/h, with a 54% reduction. The neutron and photon ambient dose equivalent rates outside the door were 5.8 μSv/h and 6.0 μSv/h, respectively, before renovation, and 0.14 μSv/h and 1.6 μSv/h, respectively, after renovation. Conclusion For a 10 MV accelerator room, neutron shielding and protection measurements are necessary, especially for rooms with short mazes. The Falcão method provides the best estimate of neutron dose rates inside and outside the door. Using boron-containing polyethylene plates as maze wall lining is an economical and effective shielding method.

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.