Objective To systematically analyze the medical radiation exposure levels in a district of Ningbo City and to provide a scientific basis for the reasonable and effective control of medical radiation exposure. Methods Based on the radiological diagnosis frequency and dose information system, basic medical radiation exposure data were collected, such as radiation doses received by patients in various X-ray diagnostic examinations, from all 13 public medical institutions in a district of Ningbo City from January 1 to December 31, 2020. The data were analyzed for the percentage and collective effective dose of various diagnostic examinations, the distribution of examinations by sex and age, and the number of patients undergoing two or more examinations and their cumulative doses within multiple time intervals. Results Among medical X-ray diagnostic examinations in the district, the percentages of CT examination and routine photography examination were 50.88% and 47.93%, respectively, and the collective effective dose of CT examination accounted for 97.75%. By age and sex, the frequency of examination was the highest in the age group of 45-54 years, and the frequency of examination in the male was higher than that in the female before age 55. The annual effective dose for two patients exceeded 100 mSv. Conclusion In this study, CT examination accounted for up to 50.88% of all medical X-ray diagnostic examinations, and contributed 97.75% of the collective effective dose, highlighting the need for particular attention to the justification of medical radiation exposure from CT.

Objective To evaluate the application of three deep learning algorithms in automatic segmentation of clinical target volumes (CTVs) in high-dose-rate brachytherapy after surgery for endometrial carcinoma. Methods A dataset comprising computed tomography scans from 306 post-surgery patients with endometrial carcinoma was divided into three subsets: 246 cases for training, 30 cases for validation, and 30 cases for testing. Three deep convolutional neural network models, 3D U-Net, 3D Res U-Net, and V-Net, were compared for CTV segmentation. Several commonly used quantitative metrics were employed, i.e., Dice similarity coefficient, Hausdorff distance, 95th percentile of Hausdorff distance, and Intersection over Union. Results During the testing phase, CTV segmentation with 3D U-Net, 3D Res U-Net, and V-Net showed a mean Dice similarity coefficient of 0.90 ± 0.07, 0.95 ± 0.06, and 0.95 ± 0.06, a mean Hausdorff distance of 2.51 ± 1.70, 0.96 ± 1.01, and 0.98 ± 0.95 mm, a mean 95th percentile of Hausdorff distance of 1.33 ± 1.02, 0.65 ± 0.91, and 0.40 ± 0.72 mm, and a mean Intersection over Union of 0.85 ± 0.11, 0.91 ± 0.09, and 0.92 ± 0.09, respectively. Segmentation based on V-Net was similarly to that performed by experienced radiation oncologists. The CTV segmentation time was < 3.2 s, which could save the work time of clinicians. Conclusion V-Net is better than other models in CTV segmentation as indicated by quantitative metrics and clinician assessment. Additionally, the method is highly consistent with the ground truth, reducing inter-doctor variability and treatment time.

Objective To study the unqualified items in the reported quality control tests of linear accelerators, analyze the issues in quality control tests, and propose the key points and development directions for accelerator quality control test in China. Methods A literature review was conducted using the CNKI database to analyze the qualified rates of test items and the issues in quality control tests. Results In the literature on the quality control tests of linear accelerators, except for a few provinces where the qualified rates of all test items were 100%, unqualified items were reported in most of the literature. There were unqualified items related to X-ray and electron beam in different reports. Error of dose indication was the unqualified item with the highest occurrence rate in X-ray test, and the item with the lowest qualified rates in X-ray and electron beam tests. The lowest qualified rate of X-ray dose indication error was 73.5% in 2016, and the lowest qualified rate of electron beam dose indication error was 46.2% in 2017. Conclusion Tests should be carried out strictly according to the items and intervals specified by the quality control test standards. Hospitals, radiation health technology service institutions, and health administrative departments should each fulfill their respective responsibilities, work together, and place emphasis on ensuring effective quality control tests of linear accelerators to further enhance the overall quality control standards for these devices.

Objective:To analyze the eye lens dose and annual effective dose to interventional radiation workers in some hospitals of Xinxiang city from 2020 to 2022, and to ascertain the dose to interventional radiation workers.Methods:By using TLDs, the eye lens dose Hp(3) and annual effective dose Hp(10) were monitored for three consecutive years in six hospitals in Xinxiang city. The lens doses and annual effective doses to intervention radiation workers in different years in different-level hospitals and departments were analyzed. Results:From 2020 to 2022, a total of 117 people were monitored. The left eye lens dose range was 0.12-164.24 mSv, and the right eye lens dose range was 0.07-51.64 mSv. The average annual dose was 8.56 mSv for left eye lens and 4.49 mSv for right eye lens The average annual dose distribution in the MDL-5 mSv range for the left and right eye lens was 60.68% and 73.50%, respectively. 9.41% (11 people) of the left eye lens doses exceeded 20 mSv. The annual effective doses range was 0.11-31.27 mSv, with average annual dose of 2.56 mSv. The proportion of average annual effective doses mainly distributed in the range of MDL to 1.25 mSv was 52.14%, with 2.56% annual effective dose exceeding 20 mSv. There was no significant difference in left and right eye lens dose and annual effective dose between the tertiary hospitals and the secondary hospitals in three years ( P>0.05). Compared with different departments, the cumulative per capita dose in three years was statistically significant (left eye H=11.42, right eye H=13.72, annual effective dose H=25.94, P<0.05). The lens dose and annual effective dose in neurology department were lower than those in cardiology department and comprehensive intervention department ( Zcardiology department=-3.33, -3.78, -4.83, P<0.05; Zcomprehensive intervention department=-2.71, -2.63, -4.39, P<0.05). Conclusions:Most of the annual equivalent dose and annual effective dose to eye lens of the interventional radiation workers in Xinxiang city meet the national limits, but some of them have higher doses and exceed the national limits. It is suggested that the routine and continuous monitoring of eye lens doses to interventional radiologists should be strengthened while routine monitoring of annual effective dose, and attention should be paid to the eye lens and annual effective dose to interventional radiologists in secondary hospitals to improve the awareness of protection.

Objective:To estimate and analyze the levels of occupational exposure of aircrews in China, and to provide scientific basis for strengthening occupational health management.Methods:Through the FlightAware website, the flight data were collected of a total of 104 routes flying between airports with large passenger volume in China. Four kinds of cosmic radiation dose estimation programs CARI, SIEVERT, PCAIRE, and JISCARD-EX were compared and analyzed from the aspects of covering the number of airports in China, program user experience and example calculation of airline effective dose. Based on route logs, CARI-7A was applied to estimate the levels of occupational exposure of Chinese aircrews to cosmic radiation.Results:The difference in the effective doses calculated by use of these four cosmic radiation dose estimation programs for the routes with different solar activity levels was statistically significant ( M=7.52-180.98, P<0.05). The annual effective dose estimated by PCAIRE for 68 routes from 2014 to 2021 was significantly higher than that estimated by CARI-7A ( Z=2.52, P<0.05). Based on CARI-7A, the annual effective doses from cosmic radiation to aircrews in China from 2014 to 2021 were estimated, being 1.26 (0.57-2.35) mSv for flight attendants and 1.03 (0.47-1.92) mSv for pilots. The effective dose from cosmic radiation to aircrews on a single flight on some high-frequency routes in China ranged from 0.57 to 6.88 μSv. Conclusions:The level of occupational exposure of Chinese aircrews to cosmic radiation meets the requirements of national standards, but is higher than that of occupational exposure from medical and industrial applications of radiation, so it is still necessary to further strengthen the mamagememt of occupational exposure and occupational health of aircrews.

With the awareness of the hazards of ionizing radiation to human health and the consequent research on the biological effects and protective measures against ionizing radiation, the radiological health has gradually developed. Therefore, as one of the five major areas of health under the traditional public health system, the study on radiological health mainly involves the harmful effects of ionizing radiation on human health and its comprehensive protection measures. After nearly a century of vigorous development ince the 1930 s and 1940 s, the level of the discipline of the radiological health and the effectiveness of radiological hygiene work in China have been greatly improved at this stage. This paper provides a brief overview of the history, current status, and work content of the radiological health research and radiological hygiene work in China, with a view to contributing to the future development of radiological hygiene work in China.

OBJECTIVE: We aimed to analyze the current indoor radon level and estimate the population risk of radon-induced lung cancer in urban areas of China. METHODS: Using the passive monitoring method, a new survey on indoor radon concentrations was conducted in 2,875 dwellings across 31 provincial capital cities in Chinese mainland from 2018 to 2023. The attributable risk of lung cancer induced by indoor radon exposure was estimated based on the risk assessment model. RESULTS: The arithmetic mean (AM) and geometric mean (GM) of indoor radon concentrations were 65 Bq/m³ and 55 Bq/m³, respectively, with 13.6% of measured dwellings exceeding 100 Bq/m³ and 0.6% exceeding 300 Bq/m³. The estimated number of lung cancer deaths induced by indoor radon exposure was 150,795, accounting for 20.30% (95% CI: 20.21%-20.49%) of the lung cancer death toll. CONCLUSION This study provided the most recent data on national indoor radon levels in urban areas and the attributable risk of lung cancer. These results served as an important foundation for further research on the disease burden of indoor radon exposure and radon mitigation efforts.
Radon/analysis* ; China/epidemiology* ; Air Pollution, Indoor/analysis* ; Lung Neoplasms/etiology* ; Humans ; Cities/epidemiology* ; Air Pollutants, Radioactive/adverse effects* ; Neoplasms, Radiation-Induced/etiology* ; Risk Assessment ; Radiation Monitoring

With the rapid development of pet hospitals and the increasing application of radiological diagnosis in China, the protection of staff and assistants in these hospitals is worthy of attention. Based on the progress in international management and research with respect to radiological diagnosis and protection in animal hospitals, this paper presents a brief review of the current situation, existing problems and management regulations of animal hospitals in China. It summarizes typical issues that may be encountered in radiation protection by government departments, animal hospitals, radiation professionals and assistants in animal hospitals. It also puts forward the key points of radiation protection in animal hospitals in China, which can provide scientific suggestion to assist government in decision-making and standardizing and improving the radiation protection in animal hospitals.

Objective:To evaluate the radiation shielding performance for a novel self-shielded ZAP-X radiotherapy system used for intra-cranial and neck treatments. The present evaluation was performed according to the relevant Chinese national standards and the clinical placement of the radiotherapy system in an unshielded treatment room.Methods:The radiation source of the ZAP-X was a 3 MV linear accelerator. A total of 33 detection sites were selected surrounding the self-shielded system at 1.3, 2.3 and 3.3 m away from the periphery of the equipment. The maximum ambient dose equivalent rate in each irradiation condition was measured accordingly. A commonly used clinical treatment plan was selected to simulate the treatment process. During the delivery of this treatment plan, the cumulative doses of these 33 sites were measured, separately. The applicable current radiation protection standard for radiotherapy in China was chosen to evaluate the radiation shielding performance of the system.Results:According to the measurement result of the ambient dose equivalent rates along the aforementioned perimeter lines, a suggestion was put forward to redefine the existing 1 m controlled area by determining the distance at which the instantaneous dose rate of 10 μSv/h will not be exceeded. This is to meet the requirements of the Chinese standard GBZ 121-2020.Conclusions:According to the existing Chinese national radiation protection standards, the self-shielded radiotherapy system in the unshielded treatment room has the clinical applicability in China. But for such a novel self-shielded system, the corresponding performance testing and radiation protection standards shall be formulated.

In order to accurately master and understand the national occupational health standard Diagnosis for Occupational Radiation Thyroid Disease(GBZ 101-2020), the significance of the publication of this standard, the relevant background, the basic principles of the revision, the main basis for technical content revision, and the application of the standard are described. To provide guidance for t the physcians for occupational disease diagnosiss to understand the diagnostic principles, make correct diagnosis and avoid confusion in using the standard, so as to better protect the occupational health rights of radiation workers.