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 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 study the causes and influencing factors of no seeking medical treatment among pneumoconiosis patients. Methods: Using stratified sampling method and typical survey method, we carried out the questionnaire survey in nine provinces in China including the east, the medium and the western region using a questionnaire on the seeking medical behavior pf pneumoconiosis patients and the influencing factors. The subjects include occupational pneumoconiosis cases and clinically diagnosed cases and the response rate is 94.3 percent. The data was entered twice with epidate3.1 and error detection and statistical analysis was completed with SPSS 20.0. Chi-square test was used for univariate analysis, and multivariate logistic regression was used for multivariate analysis. Results: One thousand and thirty-seven subjects were investigated with average age 55.9±11.2 years. Seventy percent of them were silicosis and 21.9 percent were coal worker’s pneumoconiosis with 67.5 percent of them residing permanently in the countryside, and 37.9 percent of their education background were primary school culture and 33.1 percent of them had junior high school culture. Thirty two point six percent of respondents had no personal income with a median monthly income of 1 200 yuan. Four hundred and thirty four of subjects hadn't seek medical treatment since they got the pneumoconiosis accounting for 41.9 percent with three hundred and thirty seven of them hospitalized directly. The reasons of no seeking medical treatment for the respondents mainly include the self-induction symptoms lighter, the high cost of treatment and cannot claiming the payment of the medical expenses, buying drugs in drugstore, thinking that no medicine can cure pneumoconiosis or no effect, complex procedures, too far away from medical institutions, no unaccompanied, needing a long time or no time, communication disorders, etc. accounting for 44.4 percent, 24.6 percent, 10.9 percent, 9.1 percent, 6.9 percent, 4.4percent, 3.2 percent, 2.9 percent, 1.9 percent, 1.5 percent, respectively. The results of multivariate analysis showed the main characteristics of subjects with restrictions to the outpatient health service utilization are as follows: demographic sociological indicators such as registered permanent residence area is western (OR_western=2.18, 95%CI:1.38-3.43) , more than seventy five years old (OR_{over 75}=6.82, 95%CI:2.04-22.9) , unemployment, temporary or permanent employment (OR _unemployment=1.90, 95%CI:1.17-3.08; OR_{temporary employment}=3.11, 95%CI:1.57-6.14; OR_{permanent employment}=2.10, 95%CI:1.18-3.74) , self-rated health score of 50 or above (OR_{self-rated-70}=2.04, 95%CI:1.18-3.51; OR_{self-rated-90}=3.00, 95%CI:1.97-5.37; OR_{self-rated 90}=2.95, 95%CI:1.74-8.07) ; with increase to the outpatient health service utilization are breath with difficulty (OR=0.57, 95%CI:0.41-0.78) , emphysema (OR=0.48, 95%CI:0.26-0.90) , hospitalized with pneumo-coniosis (OR=0.12, 95%CI:0.07-0.20) . Conclusion Pneumoconiosis patients no covered by injury insurance should be orderly included in the basic medical security system, and be given the medical treatment actively; It should be strengthened the health management for the pneumoconiosis patients and correctly guided the utilization of medical services.