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 obtain the medical exposure frequency data of residents through a questionnaire survey on mobile phone networks in the community, and to analyze the main influencing factors. Methods A snowball sampling method was used to expand the sampling from medical staff in a county hospital to the community. The questionnaire included personal information such as occupation category, type of medical insurance, and education level as well as basic radiation-related knowledge and medical exposure type and frequency of respondents received in 2021. A logistic regression model was used to analyze the influencing factors of medical exposure. Results A total of 223 respondents were investigated, and 12.56% of them received radiological diagnosis and radiotherapy in 2021. The proportion of males receiving medical exposure was significantly higher than that of females (19.64% vs 10.18%). The likelihood of the person receiving medical exposure increased considerably with age, with the proportion of residents receiving medical exposure at 20, 30, 40, and 50 years of age being 6.25%, 7.95%, 19.23%, and 33.33%, respectively. Of persons who received medical exposure, 57.14% underwent CT scans. Persons participating in the new rural cooperative medical system were likely less to receive radiological diagnosis and radiotherapy than urban workers and residents (OR = 0.55, CI:0.13-2.23, P > 0.05). Conclusion Questionnaire survey in the community can obtain more information about the medical exposure of residents, and age and type of medical insurance are important factors affecting the frequency of medical exposure.

Objective To address the absence of matrix specified for the determination of intrinsic uniformity in the current standard, and to investigate the effect of source distances on intrinsic spatial linearity, the intrinsic uniformity and intrinsic spatial linearity of 16 probes in eight SPECT devices were measured and analyzed with different matrices and source distances, in order to determine the optimal measurement conditions. Methods According to the standard Specification for Testing of Quality Control in Gamma Cameras and Single Photon Emission Computed Tomograph (SPECT) (WS 523—2019), the intrinsic uniformity was measured using 64 × 64 and 256 × 256 matrices and the intrinsic spatial linearity was measured using of 1.7 and 3 m source distances. Results When intrinsic uniformity was measured with the 64 × 64 matrix, more than 50% of the probes showed lower values. When intrinsic spatial linearity was measured with the 3 m source distance, more probes showed lower values. Conclusion The 64 × 64 matrix is recommended for the determination of intrinsic uniformity and a source distance of ＞5 FOV is recommended for the measurement of intrinsic spatial linearity.

Objective:To study the healthcare level (HCL) in China and its influencing factors.Methods:By using the data reported in the China statistical yearbook published by the National Bureau of Statistics and in other public literature, HCL was calculated in terms of the number of population and physicians in the whole country and various provinces. Multiple regression was used to analyze the relationship between HCL and regional population, area, number of administrative divisions and gross domestic product (GDP). Pearson correlation analysis was applied to analyze the relationship between healthcare level and medical radiation frequency. Results:Since 2015, Chinese HCL value was lower than 1 000, but there were two provinces with HCL value greater than 1 000 in 2019. Population and GDP were the influencing factors for the HCL, with correlation coefficients of 0.416 and -0.583, respectively. There was a correlation between HCL and medical exposure frequency of Chinese population( r= -0.620, P=0.028). Conclusions:Chinese HCL value was 542 in 2020, but there has been great differences between various provinces. HCL as an indicator of medical exposure assessment needs further research in China.

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.

Objective:To analyze the influencing factors on initial testing qualified rate of condition monitoring of digital radiography (DR) devices in China and provide the scientific basis for key points of national medical radiation protection monitoring work.Methods:The data of quality control detection of DR devices, reported by 31 provinces in 2020, were collected from National Radiation Health Information Platform-National Medical Radiation Protection Monitoring System. Logistic regression was used to analyze the related influencing factors of initial testing qualified rate of condition monitoring of DR devices.Results:The result of logistic regression analysis showed that the nature of radiological health technical service institutions, the level of medical and health institution and the regions where they are located in China were the independent influencing factors of initial testing qualified rate of condition monitoring of DR devices ( χ2=15.41-21.18, P < 0.05). Private institution group ( OR=1.714, 95% CI: 1.310-2.243), tertiary hospital group ( OR=1.710, 95% CI: 1.310-2.232) and secondary hospital group ( OR=1.540, 95% CI: 1.203-1.971) had a higher qualified probability of DR devices, while western region group ( OR=0.670, 95% CI: 0.526-0.852) had a lower qualified probability of DR devices. Conclusions:Supervision on quality control of DR devices should be strengthened, such as strengthening the random inspection and double-check to the devices. And great attention should be paid to the quality control testing of DR devices in the western China and in the primary and ungraded hospitals.

The rapid development of medical application of ionizing radiation has seen a range of safety and protection problems that might be of importance. This paper aims to introduce the current situation and existing problems in the public medical exposure, and to propose the relevant suggestions, based on a combination of judgment of medical radiation exposure justification, quality assurance and control of equipment in radiodiagnosis and radiotherapy, occupational protection of radiation workers, and health effects on patients undergoing radiodiagnosis and radiotherapy.

Objective:To analyze the distribution of radiodiagnosis resources in China and provide data support for further optimizing the allocation of radiodiagnosis resources and improving the weaknesses in radiation protection.Methods:The survey was carried out in accordance with the unified plan and using questionnaires of the national medical radiation protection monitoring program issued from 2017 to 2019. The survey included all medical institutions performing radiodiagnosis in China. The survey indicators included distribution of medical institutions performing radiodiagnosis, number of equipment, number of radiation workers and other information, the allocation of radiation protection equipment and the frequency of radiodiagnosis. The survey was performed using questionnaire survey and reported through the national medical radiation protection monitoring information system. In terms of the organization code, the name of the organizations excludes those repeatedly reported. The original data was exported in the form of excel table from the database for the purpose of statistical analysis.Results:By the end of 2019, except Xinjiang Production and Construction Corps, Hong Kong, Macao and Taiwan regions and military systems, there were 68 924 diagnostic radiology medical institutions in China, 147 913 diagnostic radiology equipment, accounting for 91.7% of the total pieces of nationwide diagnostic radioprotective equipment. There are 367 201 radiologists in China, accounting for 76.1% of 406 830 radiologists in all medical institutions, with high allocation rate of radiation protection equipment. However, the allocation rate in first-class hospitals was the lowest among all levels of hospitals. The piece of protection equipment was increased with the grade of hospital. From perspective of of economic development level, the highest was found in the eastern region, with the lowest in the central and northeast region, both of which are about 90%.Conclusions:The current status of radiodiagnosis and protection was ascertained basically through this three-year round of survey, with a large number of survey data accumulated. This survey provides data support for the development of relevant protection policies and standards at national and provincial levels. Survey data indicated that there are still nearly 1 000 direct fluorescent screen fluoroscopy machines in use in China. Relevant policies and standards should be established to gradually phase out the equipment with serious radiation hazards.

Four versions of diagnostic criteria for cerebral vascular diseases have been published since 1978 in China. Based on the three previous versions, the 2019 version conformed the new published Chinese classification for cerebral vascular disease and International Classification of Diseases-11, integrated the symptoms, signs and imaging findings, and then formulated the diagnostic criteria for main types of cerebral vascular diseases. It emphasizes the clinical manifestation and neuro-imaging findings, specifies etiology on diagnosis and becomes the most concrete and comprehensive version of diagnostic criteria for cerebral vascular diseases in China.