Objective:To investigate the effect of bed board of carbon fiber for treatment combined with fixed bottom board on verification results of Portal Dosimetry(PD)dose of intensity-modulated radiation therapy(IMRT)plan of fixed field for cervical cancer.Methods:A total of 15 patients with cervical cancer who admitted to Nanjing First Hospital from January 2019 to January 2020 were retrospectively selected,and the IMRT plans of fixed field for all patients were designed.The radiation field with 180° gantry angle was selected for each case to make the corresponding PD dose verification plan,and each verification plan included two subfields:AA180_0 and AA180_1.Three types of materials were placed between the accelerator head and the electronic portal imaging device(EPID),which included material without carbon fiber,bed board with carbon fiber for treatment,and the combination of the bed board with carbon fiber for treatment and the fixed bottom board with carbon fiber,when the Clinac iX accelerator was used to conduct verification plan for each case.The γ passing rates of the subfields(AA180_0 and AA180_1)and the total field(AA180)among three kinds of conditions,which included material without carbon fiber,bed board with carbon fiber for treatment,and the combination of the bed board with carbon fiber for treatment and the fixed bottom board with carbon fiber,were compared and analyzed.Results:For the subfield AA180_0,the γ passing rates under three different material conditions were respectively(96.09±1.38)%,(90.48±2.24)%and(81.85±2.46)%.For the subfield AA180_1,the γ passing rates under the above conditions were respectively(96.05±1.06)%,(91.86±2.22)%and(86.26±2.74)%.For the total field AA180,the γ passing rates were respectively(90.78±1.40)%,(84.82±2.56)%and(78.49±3.18)%.The γ passing rates of the subfield AA180_0,subfield AA180_1,and the total field AA180 showed statistically significant differences among the three different material conditions(F=177.80,80.00,91.42,P<0.01).Compared with materials without carbon fiber,the γ passing rate of the total field AA180 of the combination of the bed board with carbon fiber for treatment and the fixed bottom board with carbon fiber significantly decreased by 12.29%.Conclusion:In the PD dose verification of IMRT for cervical cancer,the bed board with carbon fiber for treatment combined with the fixed bottom board will produce adverse effect for the verification results.The effect of the single use of bed board for treatment is relatively small.The combined use of the bed board with carbon fiber for treatment and the fixed bottom board will lead to a significant deterioration in the verification result of PD dose.

Objective:To explore the structural relationship between WMSDs in the upper limbs and various risk factors in the occupational population in China, based on a large sample epidemiological survey and structural equation analysis, and to establish a structural equation model, so as to lay a foundation for the prevention and control of such diseases.Methods:The Chinese version of the Musculoskeletal Disorders Electronic Questionnaire was used to conduct a nationwide survey on the prevalence of WMSDs in the upper extremity. Six factors related to WMSDs in the upper extremity were extracted by the classification standard of adverse ergonomic factors and their source and confirmatory factor analysis, including work organization, work type, upper extremity work posture, individual factors, upper extremity fatigue and upper extremity WMSDs. The structural equation analysis was carried out and the structural equation model was established.Results:The incidence of WMSDs and fatigue in the upper limbs was 24.44% and 43.76%, respectively. The adjusted structural equation model fitting indicators were generally up to the standard (GFI=1.000, AGFI=1.000, RMSEA=0.043, NFI=0.808, TLI=0.784) . The four exogenous latent variables of work organization, work type, upper limb work posture and individual factors were correlated. There was a strong positive correlation between job type and upper limb work posture ( r=0.865) , a moderate positive correlation between work organization and job type and upper limb work posture ( r=0.570, 0.490) , and a weak negative correlation between individual factors and the other three exogenous latent variables. Upper limb work posture and individual factors had direct effects on upper limb WMSDs, and the effect coefficients were 0.10 and 0.06, respectively. Upper limb fatigue played a mediating role between work organization, work type, upper limb work posture and upper limb WMSDs. The effect coefficient was 0.46, and the composition ratios of indirect effects were 100.0%, 100.0%, and 38.3%, respectively. The direct path effect of upper limb work posture, individual factors and upper limb WMSDs was weaker than the mediating path through upper limb fatigue. Conclusion:When carrying out the prevention and control of upper limbWMSDs, it is necessary to comprehensively consider the pathogenesis path of upper limb muscle fatigue and upper limb WMSDs caused by work organization, work type, and upper limb work posture, so as to provide theoretical reference for improving the prevention and control level of such diseases.

Objective To propose a novel method for verifying the isocenter in radiotherapy based on markers and conduct a preliminary test. Methods A feasibility experiment was conducted on wooden box phantom for radiotherapy resetting. Fifteen groups of displacement data were randomly generated,corresponding to the position deviations of the isocenter in the radiotherapy plan relative to the original isocenter. According to each set of displacement data,with the aid of movable lasers and a CT scanning couch,CT scanning was performed with two sets of markers (3 per set) affixed to the phantom which were corresponding to the original and treatment isocenters,respectively. In the Eclipse treatment planning system,the coordinate data of the original and treatment isocenters were manually verified,and the difference of coordinate data was calculated to obtain the actual displacement value. The treatment isocenter position was finally confirmed by comparing with the actual displacement. In addition,the study attempts to use threshold segmentation algorithm to automatically detect metal markers and obtain coordinate values of the original isocenter on patient-positioned CT images. In the wooden box experiment,the absolute value of the difference between the actual displacement value and the planned displacement value (?d) was used to represent the position accuracy of treatment isocenter,and the deviation value obtained with threshold segmentation algorithm for isocenter detection was ?s. Results The ?d in the X (left-right),Y (superior-inferior) and Z (anterior-superior) directions was (0.83±0.37) mm,0 (0,0.5) mm and (0.45±0.29) mm,respectively. The ?s in the X,Y and Z directions was (0.46±0.22) mm,0 (0,0.5) mm and (0.33±0.29) mm,respectively. The mean values of ?s in 3 directions were all lower than 2 mm,within the range of permissible clinical positioning error. Conclusion The method of automatically verifying treatment isocenter position based on markers is feasible,and the study provides a useful reference for radiotherapy resetting using CT simulator.

Objective:To investigate the effect of bed board of carbon fiber for treatment combined with fixed bottom board on verification results of Portal Dosimetry(PD)dose of intensity-modulated radiation therapy(IMRT)plan of fixed field for cervical cancer.Methods:A total of 15 patients with cervical cancer who admitted to Nanjing First Hospital from January 2019 to January 2020 were retrospectively selected,and the IMRT plans of fixed field for all patients were designed.The radiation field with 180° gantry angle was selected for each case to make the corresponding PD dose verification plan,and each verification plan included two subfields:AA180_0 and AA180_1.Three types of materials were placed between the accelerator head and the electronic portal imaging device(EPID),which included material without carbon fiber,bed board with carbon fiber for treatment,and the combination of the bed board with carbon fiber for treatment and the fixed bottom board with carbon fiber,when the Clinac iX accelerator was used to conduct verification plan for each case.The γ passing rates of the subfields(AA180_0 and AA180_1)and the total field(AA180)among three kinds of conditions,which included material without carbon fiber,bed board with carbon fiber for treatment,and the combination of the bed board with carbon fiber for treatment and the fixed bottom board with carbon fiber,were compared and analyzed.Results:For the subfield AA180_0,the γ passing rates under three different material conditions were respectively(96.09±1.38)%,(90.48±2.24)%and(81.85±2.46)%.For the subfield AA180_1,the γ passing rates under the above conditions were respectively(96.05±1.06)%,(91.86±2.22)%and(86.26±2.74)%.For the total field AA180,the γ passing rates were respectively(90.78±1.40)%,(84.82±2.56)%and(78.49±3.18)%.The γ passing rates of the subfield AA180_0,subfield AA180_1,and the total field AA180 showed statistically significant differences among the three different material conditions(F=177.80,80.00,91.42,P<0.01).Compared with materials without carbon fiber,the γ passing rate of the total field AA180 of the combination of the bed board with carbon fiber for treatment and the fixed bottom board with carbon fiber significantly decreased by 12.29%.Conclusion:In the PD dose verification of IMRT for cervical cancer,the bed board with carbon fiber for treatment combined with the fixed bottom board will produce adverse effect for the verification results.The effect of the single use of bed board for treatment is relatively small.The combined use of the bed board with carbon fiber for treatment and the fixed bottom board will lead to a significant deterioration in the verification result of PD dose.

Objective To propose a novel method for verifying the isocenter in radiotherapy based on markers and conduct a preliminary test. Methods A feasibility experiment was conducted on wooden box phantom for radiotherapy resetting. Fifteen groups of displacement data were randomly generated,corresponding to the position deviations of the isocenter in the radiotherapy plan relative to the original isocenter. According to each set of displacement data,with the aid of movable lasers and a CT scanning couch,CT scanning was performed with two sets of markers (3 per set) affixed to the phantom which were corresponding to the original and treatment isocenters,respectively. In the Eclipse treatment planning system,the coordinate data of the original and treatment isocenters were manually verified,and the difference of coordinate data was calculated to obtain the actual displacement value. The treatment isocenter position was finally confirmed by comparing with the actual displacement. In addition,the study attempts to use threshold segmentation algorithm to automatically detect metal markers and obtain coordinate values of the original isocenter on patient-positioned CT images. In the wooden box experiment,the absolute value of the difference between the actual displacement value and the planned displacement value (?d) was used to represent the position accuracy of treatment isocenter,and the deviation value obtained with threshold segmentation algorithm for isocenter detection was ?s. Results The ?d in the X (left-right),Y (superior-inferior) and Z (anterior-superior) directions was (0.83±0.37) mm,0 (0,0.5) mm and (0.45±0.29) mm,respectively. The ?s in the X,Y and Z directions was (0.46±0.22) mm,0 (0,0.5) mm and (0.33±0.29) mm,respectively. The mean values of ?s in 3 directions were all lower than 2 mm,within the range of permissible clinical positioning error. Conclusion The method of automatically verifying treatment isocenter position based on markers is feasible,and the study provides a useful reference for radiotherapy resetting using CT simulator.

Objective:To explore the structural relationship between WMSDs in the upper limbs and various risk factors in the occupational population in China, based on a large sample epidemiological survey and structural equation analysis, and to establish a structural equation model, so as to lay a foundation for the prevention and control of such diseases.Methods:The Chinese version of the Musculoskeletal Disorders Electronic Questionnaire was used to conduct a nationwide survey on the prevalence of WMSDs in the upper extremity. Six factors related to WMSDs in the upper extremity were extracted by the classification standard of adverse ergonomic factors and their source and confirmatory factor analysis, including work organization, work type, upper extremity work posture, individual factors, upper extremity fatigue and upper extremity WMSDs. The structural equation analysis was carried out and the structural equation model was established.Results:The incidence of WMSDs and fatigue in the upper limbs was 24.44% and 43.76%, respectively. The adjusted structural equation model fitting indicators were generally up to the standard (GFI=1.000, AGFI=1.000, RMSEA=0.043, NFI=0.808, TLI=0.784) . The four exogenous latent variables of work organization, work type, upper limb work posture and individual factors were correlated. There was a strong positive correlation between job type and upper limb work posture ( r=0.865) , a moderate positive correlation between work organization and job type and upper limb work posture ( r=0.570, 0.490) , and a weak negative correlation between individual factors and the other three exogenous latent variables. Upper limb work posture and individual factors had direct effects on upper limb WMSDs, and the effect coefficients were 0.10 and 0.06, respectively. Upper limb fatigue played a mediating role between work organization, work type, upper limb work posture and upper limb WMSDs. The effect coefficient was 0.46, and the composition ratios of indirect effects were 100.0%, 100.0%, and 38.3%, respectively. The direct path effect of upper limb work posture, individual factors and upper limb WMSDs was weaker than the mediating path through upper limb fatigue. Conclusion:When carrying out the prevention and control of upper limbWMSDs, it is necessary to comprehensively consider the pathogenesis path of upper limb muscle fatigue and upper limb WMSDs caused by work organization, work type, and upper limb work posture, so as to provide theoretical reference for improving the prevention and control level of such diseases.

Objective:To analyze the distribution characteristics of work-related musculoskeletal disorders (WMSDs) among the occupational population in China's key industries during the period from 2018 to 2023, and to provide data support for the formulation of targeted prevention strategies.Methods:Between January 1, 2018, and December 31, 2023, a cross-sectional epidemiological survey and a retrospective investigation were conducted in seven geographical regions of North China, East China, Central China, South China, Southwest China, Northwest China, and Northeast China, using a combination of epidemiological cross-sectional and retrospective surveys. The industries were stratified according to the degree of closeness to WMSDs, the size of the occupational population, and the importance of the national economy, and then cluster sampling was conducted according to the size of the enterprises (large, medium, and small) within each stratum. Representative enterprises were selected, and workers who had been employed for more than one year and met the inclusion criteria were selected as the study subjects. The survey subjects completed the Chinese version of the Musculoskeletal Disorders Survey Questionnaire online by scanning a QR code. A total of 88, 609 valid questionnaires were collected. Continuous data were described by means and standard deviations, and the standardized incidence rates of WMSDs were evaluated using chi-square tests to compare the standardized incidence rates of different body parts.Results:The standardized prevalence rate of WMSDs among the frontline working population in China was 36.7%, with the top three being the neck (21.37%), shoulders (18.23%), and lower back (14.92%). There was a statistically significant difference in the standardized prevalence rate of WMSDs between different body parts (χ 2=47577.82, P<0.05). The lowest standardized prevalence rate of WMSDs was found in the southeast coastal region of China (32.54%), while the highest was in the northwest (49.70%) and northeast regions (46.16%). The standardized prevalence rate of WMSDs decreased from 42.88% in 2018 to 29.94% in 2023. The micro-enterprise observation group had a higher concentration of WMSDs in the neck (20.66%), lower back (17.95%), and shoulders (17.79%), while the large enterprise observation group had a higher concentration in the neck (20.54%), shoulders (17.52%), and lower back (14.65%). Among the industries surveyed, the highest standardized prevalence rate of WMSDs was found in the healthcare industry (53.18%), followed by the toy manufacturing industry (50.54%), the automotive manufacturing industry (43.39%), general aviation services (42.71%), and the ship and related equipment manufacturing industry (40.56%). The standardized prevalence rate of WMSDs among women was significantly higher than that of men ( OR value=1.44, P<0.05). In addition, the standardized prevalence rate of WMSDs with multiple affected body parts (four or more body parts affected simultaneously) was higher, and the risk of WMSDs increased with subjective fatigue, showing a significant "S-shaped" trend (the OR value was 2.19, 3.16, 4.71, 5.49, and 3.97 when the RPE was 13, 15, 17, 19, and 20, respectively. χ 2trend=17.23, P<0.001) . Conclusion:The distribution characteristics of WMSDs in key industries in China show obvious differences in different parts, regions, time, enterprise scale, industry and population attributes. Agriculture, pharmaceutical manufacturing, packaging and decoration and other printing industries have a high proportion of WMSDs in multiple parts at the same time and in a single site. It is necessary to study and implement precise preventive measures according to specific regions, industries and enterprise scales, as well as the characteristics of multi-site WMSDs, so as to effectively protect the health and well-being of the working population.

Objective:To explore the occupational contact characteristics of work-related musculoskeletal disorders (WMSDs) among key occupational groups in China, assess the impact of occupational factors on the occurrence of WMSDs, and propose corresponding preventive strategies.Methods:Between January 1, 2018, and December 31, 2023, a cross-sectional epidemiological survey method was employed to retrospectively investigate the occurrence of WMSDs and related occupational factors. Valid questionnaire data from 88609 on-the-job workers in 441 enterprises across 29 industries or job types in seven regions of China were collected, and the relationship between WMSDs and various occupational factors was discussed using multifactorial logistic regression analysis. Odds ratios ( OR) and their 95% confidence intervals ( CI) were calculated to assess the impact of different factors on the risk of WMSDs occurrence, with all statistical tests performed as two-tailed tests, using P<0.05 as the criterion for statistical significance. Results:Among the surveyed subjects, 59989 were male, accounting for 67.7% (59989/88609) ; 28620 women, accounting for 32.3% (28620/88609). The standardized incidence rate of work related musculoskeletal disorders (WMSDs) in 9 parts of the body was statistically significant ( P<0.05) among different working age groups without considering specific parts. The average length of service for onset of WMSDs (regardless of location) is (4.52±2.67) years, and there is a statistically significant difference in the length of service for onset of WMSDs in different locations ( P<0.05). As the frequency of heavy object handling increases, the standardization rate and OR value of WMSDs in various parts show a significant increase trend. The incidence of WMSDs is significantly correlated with maintaining poor work posture for a long time, frequent repetitive operations, and heavy object handling ( OR=1.52, 1.45, 1.63, P<0.01) . Conclusion:This study reveals that the risk of WMSDs in China's occupational population shows a non-linear change with increasing length of service, especially with a significant increase in 10 to 25 years of service. Poor work posture, frequent repetitive operations, and heavy object handling are significantly correlated with WMSDs, providing a scientific basis for developing more accurate and effective prevention strategies for WMSDs.

Objective:To investigate the relationships and impacts between various occupational ergonomic hazards and hand and wrist fatigue, as well as work-related musculoskeletal disorders (WMSDs) of the hand and wrist, and to propose targeted preventive and intervention measures for adverse occupational ergonomic factors causing WMSDs of the hand and wrist.Methods:From 2018 to December 2023, a nationwide epidemiologic survey study of wrist WMSDs was conducted using the Chinese version of the electronic questionnaire system for musculoskeletal disorders.A total of 88, 609 valid questionnaires were collected. The exclusion criteria were as follows: patients with congenital spinal deformities, as well as those with wrist WMSDs caused by external injuries, infectious diseases, and malignant tumors. A total of 73, 497 questionnaires were finally included in the study analysis, with an effective questionnaire return rate of 82.5%. Exploratory factor analysis was used to analyze and summarize the factors affecting wrist WMSDs from the questionnaires, including individual factors, work organization, work type, wrist work posture, wrist fatigue, and wrist WMSDs as latent variables, and to hypothesize, fit, and validate the structural aspect model, as well as to conduct mediation effect analysis.Results:The incidence of WMSDs and fatigue in wrist was 12.19% and 16.30% respectively. The fitting indexes of the modified structural equation model were basically up to the standard (GFI was 0.981, AGFI was 0.973, RMSEA was 0.031, NFI was 0.863, IFI and CFI were 0.865). There is a correlation between individual factors, work organization, wrist working posture and work type. There was a low negative correlation between individual factors and other factors, and there was a positive correlation between work organization, work type and wrist WMSDs ( r=0.346, 0.295), and these two factors were positively correlated with wrist fatigue height ( r=0.862, 0.599), and were positively correlated with wrist working posture ( r=0.443, 0.620). There was moderate positive correlation between wrist working posture and wrist fatigue ( r=0.469). The three most influential factors on wrist WMSDs were work organization, individual factor and work type, and the path coefficients were 0.247, 0.210 and 0.136, respectively. The first two factors that have the greatest influence on wrist fatigue are work organization and work type, and the path coefficients are 0.758 and 0.188, respectively. Individual factors, work type, wrist working posture and work organization had direct effects on wrist WMSDs, and the effect values were 0.093, 0.253, 0.718 and 0.583, respectively. Wrist fatigue played a partial mediating role between individual factors, work type, wrist working posture and work organization and wrist WMSDs, with the indirect effect ratio of 25.6%, 45.8%, 3.2% and 65.5%. Conclusion:Wrist fatigue plays an important mediating role in the path of various factors affecting wrist WMSDs, especially in the path of work organization, work type, individual factors and wrist WMSDs. Poor wrist working posture is an important risk factor that directly affects the occurrence of wrist WMSDs.

Objective:To establish a structural equation model of lower back pain and its risk factors in occupational population in China based on a large-sample occupational epidemiological survey and structural equation analysis, so as to lay the foundation for the prevention of this disease.Methods:A total of 73497 occupational epidemiological cases were selected from June 2018 to December 2023 using the Chinese version of the Musculoskeletal Disorders Electronic Questionnaire. The results were analyzed using ergonomic hazard factors and their risk source classification criteria. Confirmatory factor analysis was then applied to extract individual factors, work organization, working postures, work types, muscle fatigue, and lower back pain. These factors were subsequently classified into six categories and structural equation model was established.Results:The main structural reliability and validity indexes of the structural equation model of lower back pain and its adverse ergonomic factors after adjustment were basically up to standard[goodness of fit index (GFI) was 0.956, the adjusted goodness of fit index (AGFI) was 0.944, the root mean square error of approximation (RMSEA) was 0.043, the normed fit index (NFI) was 0.922, the comparative fit index (CFI) was 0.923, and the Tucker-Lewis index (TLI) was 0.908], and the model fit was good. There were correlations among four exogenous latent variables: individual factors, work organization, working postures and work types. Among them, individual factors had a weak negative correlation with the three exogenous potential variables of work organization, working postures and work types ( r=-0.30, -0.11, -0.18), and work organization had a moderate positive correlation with working postures and work types ( r=0.49, 0.55). There was a strong positive correlation between work types and working postures ( r=0.72). The direct path coefficients of individual factors, working postures and muscle fatigue were 0.07, 0.11 and 0.40, respectively. The direct path coefficients of work types were -0.07. There was an indirect path mediated by muscle fatigue between work types, working postures and work organization and lower back pain, and the indirect path coefficients were: work types-muscle fatigue-lower back pain (0.15), working postures-muscle fatigue-lower back pain (-0.04) and work organization-muscle fatigue-lower back pain (0.27) . Conclusion:When carrying out the prevention and control of lower back pain, the pathogenesis of lower back pain induced by workers' muscle fatigue caused by work organization, working postures, and work types factors should be comprehensively considered, so as to provide a theoretical reference for improving the prevention and control level of lower back pain.