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 With the increase in pet-owning households in China, veterinary clinics have increased at an annual rate of 19.86%. However, the management blind area that may exist in multi-department supervision has led to a significantly worse working environment of radiation workers in veterinary clinics than that of medical institutions. The purpose of this study was to understand the levels of occupational external exposure of radiation workers in veterinary clinics in China, analyze the occupational risks faced by radiation workers in veterinary clinics, contribute to the protection of the occupational health of radiation workers, and provide data and scientific basis for the formulation of national relevant regulations and standards. Methods The individual dose monitoring data of radiation workers in selected veterinary clinics in 2022 were obtained from the National Individual Dose Registration System. Results This study involved 1868 radiation workers from 1216 veterinary clinics in 28 provinces and municipalities in China. The maximum annual effective dose was 8.93 mSv, the annual collective dose was 536.77 man·mSv, the average annual effective dose was 0.29 mSv, and the median was 0.15 mSv. The largest proportion of individuals (94.5%) received a dose of less than 1.0 mSv, while 5.4% had doses ranging from 1.0 mSv to less than 5.0 mSv. For radiation workers with an annual effective dose of 1.0 mSv and above, the individual distribution ratio of radiation workers in veterinary clinics was significantly higher compared with those in medical institutions and industrial applications (P < 0.05). Conclusion The levels of occupational external exposure of radiation workers in veterinary clinics meet the requirements of national standards. However, attention should still be paid to the radiation protection of radiation workers in veterinary clinics. This includes enhancing the responsibility awareness of veterinary clinic owners, strengthening protection training for radiation workers, protecting the occupational health of practitioners, and preventing the occurrence of occupational radiation diseases.

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.

Objective To explore the features of sleep quality and its relationship with perceived stress and occupational stress in military personnel serving in high-altitude regions.Methods Cross-sectional study design was adopted in this study.In February 2023,self-designed demographic data questionnaire,Pittsburgh sleep quality index(PSQI),perceived stress scale(PSS-10)and job content questionnaire(JCQ)were applied to survey 3 784 soldiers from a unit stationing in plateau subjected by cluster sampling.Results The total score of PSQI was 5.37±2.78 in the participants,and the total score and the scores of each dimension of PSQI were significantly higher than the national norms for Chinese(P＜0.001).There were significant differences in PSQI scores among different age,length of military service,nationality,length of stationing in plateau,education level and family structure(P＜0.001).The low perceived stress group had significantly lower PSQI scores than the high perceived stress group(t=-12.108,P＜0.001).Regulatory effect analysis showed that the length of stationing in plateau,work autonomy,work psychological requirements,and social support in the work environment could modulate the relationship between perceived stress and sleep quality(t=8.326,-3.788,-2.145,-6.656,P＜0.05),and explained 14.6％,7.6％,7.0％and 7.9％of the variance of sleep quality,respectively.Conclusion The military personnel serving in high-altitude regions have a poor sleep quality.Age,time of military service,time of stationing in plateau,nationality,family structure,education level,perceived stress,and occupational stress are important factors affecting their sleep quality.The length of stationing in plateau time and occupational stress,can modulate the relationship between perceived stress and sleep quality.

Objective To analyze the factors influencing the levels of occupational exposure in medical radiation workers in China, and to provide a scientific basis for determining the key points of radiation protection in the medical sector. Methods The individual monitoring data on occupational external exposure in medical radiation workers in 2021 were collected from the “National Individual Dose Registry”. The Chi-squared test and logistic regression were used to analyze the factors influencing the levels of occupational exposure in medical radiation workers. Results The Chi-squared test showed that gender, occupational category, medical institution category, region, number of radiation workers per thousand population, and regional per capita GDP were significantly associated with occupational exposure in medical radiation workers exceeding the annual effective dose of 5 mSv and an annual effective dose limit of 20 mSv (χ² = 21.456−262.329, 7.601−78.650, P < 0.05). The logistic regression analysis further showed that gender, occupational category, region, and number of radiation workers per thousand population were factors influencing the occupational exposure in medical radiation workers exceeding the annual effective dose of 5 mSv (χ² = 14.621−170.857, P < 0.05); gender, occupational category, region, and regional per capita GDP were factors influencing the occupational exposure in medical radiation workers exceeding the annual effective dose of 20 mSv (χ² = 5.401−48.709, P < 0.05). Conclusion Male radiation workers in interventional radiology and in central China have high risks of exceeding annual effective doses of 5 and 20 mSv. Moreover, high number of radiation workers per thousand population and regional per capita GDP are associated with low risks. Medical institutions should maintain a sufficient number of radiation workers and strengthen training on radiation protection knowledge for male and interventional radiology workers to enhance their radiation protection awareness. Investigation of the factors contributing to the high occupational exposure in central China should be intensified, and targeted effective measures should be conducted to reduce the occupational exposure in medical radiation workers.

Objective To establish a model for estimating the eye lens dose of the first operator in interventional therapy based on the Monte Carlo simulation, and to provide a scientific basis for the rapid and accurate evaluation of the eye lens dose for radiation workers in interventional therapy. Methods Based on the MIRD phantom and eye model for adult Chinese males, the MCNPX program was used to establish the physical model to calculate the spatial distribution of radiation field and eye lens dose for the first operator. A GR200 Type A LiF (Mg, Cu, P) thermoluminescence dosimeter was used for experimental measurement to verify the simulation results. Results Monte Carlo simulation and experimental measurements showed that the spatial distribution of radiation field was symmetrical. Compared with the measured doses, the errors of the simulated eye lens dose of the first operator were between −8.3% and 7.3%. The dose of the left eye lens was higher than that of the right eye. Conclusion The Monte Carlo model constructed in this study initially realizes the simulation of eye lens dose of the first operator in interventional therapy. In the future, the model will be further optimized based on irradiation parameters such as exposure time, tube voltage, tube current, and projection direction used in clinic practice, so as to more accurately evaluate the eye lens dose of interventional therapy staff.

Objective To propose a computer recognition algorithm for solid nuclear track images based on the machine learning method, and to realize the automatic, fast and accurate recognition of nuclear tracks and improve the efficiency of solid track image analysis. Methods Firstly, 143 images containing tracks were scanned by morphological method to determine the location of suspected tracks, and 1250 material images were captured. 50% of the material were selected as the training set and 30% as the validation set for training the machine learning model. Another 20% of the material were selected as the test set for testing the model recognition result. The algorithm code was written and trained based on the MATLAB software. Results The established solid track recognition algorithm had a strong recognition capability, and the recognition accuracy of the test set could reach 84.8%. The machine learning model program constructed by the algorithm could evolve continuously with the input of training data, further improving the accuracy. Conclusion Based on image morphology and machine learning, the track recognition algorithm was investigated, by which the automatic recognition of solid tracks was better realized. In the future, we will increase the data input of the model, optimize the algorithm, and improve the recognition accuracy, in order to provide a more accurate and efficient method for automatic image track recognition.

Objective:To ascertain the levels of individual doses to radiation workers arising from occupationally external exposure in China in 2017, with an aim to provide basic data and scientific basis for prevention and control of occupational radiation sickness.Methods:Data on individual doses to monitored workers engaged in medical and industrial applications of radiation sources were collected through National Individual Dose Registry, with statistical analysis being carried out using Kruskal-Wallis H test, Mann-Whitney U test and Bonferroni method. Results:A total of 361 727 radiation workers were investigated in 2017, of which 81.6% was from medical application and 18.4% from industrial application, respectively. The average annual effective dose from medical and industrial applications were 0.353 and 0.270 mSv, respectively, with the former significantly higher than the latter ( Z=48.547, P<0.05). Furthermore, a statistically significant difference was seen in the average annual effective dose for each occupational category of medical application ( H=1 136.217, P<0.05), suggesting that the dose values for the monitored workers in nuclear medicine and interventional radiology were significantly higher than for other four medical categories ( Z=2.877-26.967, P<0.05). These dose values for the radiation workers was 0.361 mSv in tertiary hospitals, 0.397 mSv in secondary hospitals, and 0.308 mSv in primary and unrated hospitals, respectively. The dose values for the monitored workers in industrial radiography and well logging were significantly higher than for other five industrial categories of industrial applications ( Z=4.172-36.908, P<0.05). Conclusions:The average annual effective doses to the of monitored workers meet the relevant national standards. The exposure doses to the workers in nuclear medicine, interventional radiology, industrial radiography and well logging are relatively high. The necessary measures and devices for radiation protection should be further strengthened to reduce occupational exposure of workers.

Objective:To investigate the levels of dose to eye lens of interventional radiology workers in China from 2017 to 2019.Methods:The monitoring data on eye lens doses to the interventional radiology workers in 28 provinces across the country were collected from National Individual Dose Registry. Monitoring was carried out using TLDs on their left eyes and evaluated in terms of the personal dose equivalent Hp(3). By using Mann-Whitney U test and Kruskal-Wallis H test, statistical analyses were made of the average annual lens doses to interventional radiology workers in the hospitals of different types at different levels for different years. Results:From 2017 to 2019, the data on eye lens doses to 2 981 interventional radiology workers were collected, with doses ranging from below the minimum detectable level (MDL) to 64.48 mSv, the average annual eye dose of 1.38 mSv, and the annual doses incurred by 0.97% monitored workers exceeding the recently recommended dose limits, 20 mSv per year. The average annual lens dose monitored in general hospitals and in cancer hospitals were 1.33 and 1.77 mSv, respectively, without statistically significant difference ( P>0.05). The average annual lens dose in tertiary hospitals was 1.39 mSv, significantly higher than that in secondary hospitals where the value was 1.16 mSv ( Z=2.894, P<0.05). Conclusions:The estimated annual eye lens doses to the interventional radiology workers during 2017-2019 were in accordance with the current national standard GB 18871-2002, but with a few exceptions exceeding the current international standards. This means that there exists, to a certain degree, a potential risk for the eye lens in this work category to exceed the international limits. It is suggested to continue in effort to enhance the monitoring of eye lens dose for these workers and to increase risk awareness, and take effective protective measures so as to lower the level of eye lens doses.

The high-energy particles from the sun and from outside the solar system and then enter the Earth′s atmosphere and interact with the nuclei of atmospheric constituents, leading to secondary cosmic rays, which are the main radiation source to aircrew. Routine individual monitoring or dose estimation for aircrew is necessary because of the high level exposure to radiation. However, dose monitoring for aircrew is not a simple task due to the complex components of cosmic ray radiation field. To protect occupational health of aircrew, it is important to seek appropriate dose monitoring method and to be aware of cosmic radiation level. This review gives an overview of dose monitoring method, dose calculation method, and dose levels of occupational exposure of aicrew from cosmic rays, in order to provide new input for strengthening dose monitoring and health management of aircrew in China.