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Objective@#To improve radiation testing institutions’ ability and levels of personal dose monitoring for external exposure and standardize monitoring work.@*Methods@#According to Testing Criteria of Personnel Dosimetry Performance for External Exposure (GBZ 207—2016), the intercomparison programme was made, the 2021 class-based personal dose monitoring intercomparison were organized by the National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention and provincial monitoring institutions.@*Results@#A total of 150 institutions participated in the 2021 national intercomparison of personal dose monitoring capability. Of them, 143 (95.3%) passed the assessment, including 51 excellent institutions (excellent rate, 34.0%), and 7 (4.7%) failed to pass the assessments.@*Conclusion@#The 2021 national personal dosimetry performance intercomparison showed great improvements in the pass rate and excellent rate compared with previous national assessments. However, still seven institutions failed to pass this assessment, including four institu- tions with class A qualifications. The testing institutions need to find out the reasons to increase their testing ability. This class-based intercomparison improved the point-to-plane relationship between the organizing and testing institutions, help- ing the organizing institution focus on improving the testing ability of provincial testing institutions and class A radiation health service institutions.
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Objective:To enhance the capabilities of individual monitoring technology services for external exposure.Methods:The intercomparison results of the national individual monitoring for external exposure during 2015-2019 were presented, together with a summary and analysis provided of the main existing problems.Results:By 2019, 382 of individual monitoring technology service uints, from 30 provinces, autonomous regions or municipalities, participated in the individual monitoring intercomparisons results, involving disease control and prevention centers, occupational prevention and control institutions, research institutes, universities, nuclear industry, medical institutions, and companies. Except for slightly low in 2017, the pass rate in the other four years was above 90%. The excellence rate increased with the years.Conclusions:The capabilities of individual monitoring service units can meet the concerned requirements and provide standardized monitoring report for the period of 2015 to 2019, but with some being unqualified. These service units should carefully analyze and identify the reasons for the failure, standardize the quality control of laboratory, and improve the level of measurement and the ability of data analysis.
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Objective In order to improve the personal dose monitoring ability of radiation health technical institutions, and standardize the detection methods and procedures. Methods Develop adetailed assessment plan according to GBZ 207—2016 “Testing criteria of personnel dosimetry performance for external exposure”, organize a national assessment of personal dose monitoring capabilities in 2020, analyze the problems arising from the assessment, and strengthen supervision and training in the future. Results A total of 457 institutions participated in this assessment, of which 421 were qualified (including 74 excellent institutions, with an excellent rate of 16.2%), and 36 were unqualified, accounting for 92.1% and 7.9% respectively. Conclusion The number of institutions that participated in the assessment this year reaches a record high, with a passing rate 4.08% higher than that in 2019. The overall monitoring capacity of the country has been greatly improved. However, some institutions still have problems such as irregular symbol writing, unupdated detection standards, and large deviations in testing data. It is necessary to improve the ability of loboratory detection and data analysis, standardize the operation process, and ensure the quality of assessment.
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Objective@#To compare the test results of domestic and imported eye lens and ring dosimeters, and master some dosimetric performance indexes of eye lens and ring dosimeters.@*Methods@#According to IEC 62387—2012 and GBZ 128—2019, the performance of the eye lens dosimeters and ring dosimeters with the domestic thermoluminescence detectors were compared with the imported thermoluminescence detectors in photon response. The dose response deviation of the im- ported eye lens dosimeter and imported ring dosimeter was studied under the same irradiation condition. The difference of linear response between imported ring dosimeter and domestic ring dosimeter was studied under the same irradiation condition. @*Results@#The same dose was irradiated to domestic and imported thermoluminescence detectors in the imported eye lens and imported ring dosimeters, and the linear correlation coefficient all met R2 > 0.999. The maximum response devi- ation of the imported eye lens dosimeter and ring dosimeter was less than 10.0% for the same dose. Two kinds of imported ring dosimeters and one kind of domestic ring dosimeter were irradiated with the same dose, and the linear correlation coefficient all met R2 > 0.99.@*Conclusion@#Both domestic detectors and imported detectors can meet the needs of monitoring re- quirements. There was no obvious difference in linear response between imported ring dosimeter and domestic ring dosimet- er. The repeatability of imported eye lens dosimeter and imported ring dosimeter met the performance requirements of the dosimeter.
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Objective To describe the evaluation method of uncertainty in measurement of depth individual dose equivalent.Methods Based on the performance of the personal dosimeter,GUM method was used to evaluate the uncertainty of Hp(10) measurement by using a personal dosimeter.Results The relative extended uncertainty was 28％ when the measurement result was corrected by nonlinear response and energy response,as well as 33％ when not corrected in the same way.Conclusions This method can be used to effectively evaluate the uncertainty arising from personal dose equivalent Hp(10) measurement in routine monitoring.
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Objective To compare,through experimental measurements,the differences between four kinds of single and double dosimetry algorithms recommend by ICRP 139 Publication in estimating interventional radiology staff's effective dose,with aim to realize the applicability of algorithms for cardiovascular interventional diagnosis and treatment in China.Methods Measurements of organ doses were carried out with an anthropomorphic phantom equipped with thermoluminecent dosimetry and dressed with lead apron and lead collar.The effective doses were calculated using the tissue weighting factors.Meanwhile,the staff's effective doses were also obtained by the use of four kinds of single and double dosimetry algorithms.The later four effective doses were compared with those obtained with phantom methode.Results The effective doses were 0.581 mSv for phantom method,0.667 mSv for Swiss ordinance's algorithm,0.484 mSv for McEwan's algorithm,0.485 mSv for von Boetticher's algorithm and 0.726 mSv for Martin-Magee's algorithm,in ICRP 139 report respectively.The relative deviations to the results of experimental measurement were 14.8％ for Swiss ordinance's algorithm,-16.7％ for McEwan's algorithm,-16.5％ for von Boetticher's algorithm and 24.9％ for Martin-Magee's algorithm,respectively.Conclusions There are great differences between the effective doses of the first operator obtained by four dosimetry algorithms and the simulated result.From the point of view of radiation protection,it is recommended to use the Swiss ordinance's algorithm to carry out individual monitoring of the first operator in the cardiovascular interventional procedures.
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Objective To standardize the uncertainty assessment work of nationwide radiological technical service institutions in respect to individual dose monitoring, to enhance the relevant capability and to ensure the quality of assessment. Methods The 2017 nationwide individual dose monitoring assessment for external exposure was carried out, and the problems found in uncertainty assessment in the submitted reports were analyzed and summarized. Results A total of 259 personal dose monitoring technical service institutions submitted their completed assessment reports and verification/calibration certificates. The accuracy rate of Class A uncertainty evaluation was 20.8％ and that of class B 55.2％ for calibration, 50.6％ for energy response, 25.5％ for angle ring and 51.4％ non-linearity response, respectively. The accuracy rate of effective digits of the estimated values and their uncertainty was 30.4％. Conclusions The ability of these individual dose monitoring institutions to assess uncertainties remains to be improved. It is recommended to enhance systematic training of the institutions with respect to uncertainty evaluation and to standardize the assessment reports, so as to improve the accuracy of the monitoring result and the quality of accuracy reporting.
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Objective To normalize the individual dose monitoring for nationwide radiological workers and to improve individual dose monitoring ability of radiological health monitoring service institutions. Methods The 2017 annual intercomparison was carried out of nationwide external radiation individual dose monitoring result, with summary and analysis completed. Results A total of 283 monitoring service institutions were involved in the 2017 annual intercomparison. Of them, 249 were qualified, 45 excellent and 34 unqualified. The excellent rate was 15.9％ and the pass rate 88.0％. Conclusions Most of individual dose institutions could meet better the requirements by the intercomparison, but some deviated from the references to some degree. It is necessary to strengthen the laboratory operation and standardize data processing and to improve the accuracy end precision of measurement result .
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Objective To understand the dosimetric performance of energy differential type dosimeter.Methods A differential type dosimeter (CTLD-J4000) was chosed to conduct a series of dosimetric performance tests,including linear standard curves,relative response to mean photon radiation energy and incidence angle.Results The linear correlation of CTLD-J4000 energy differential dosimeter was good,with the average photon radiation energy response deviation within ± 20％ and the maximum incidence angle response deviation of 10％.The energy identification could be achieved according to the energy reference value provided by the manufacturer to a certain extent.Conclusions Further experiments are needed to find out the factors influencing measurement result from different dose values and incidence angles.
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Objective To investigate demographic factors implicated in the functional maturation of autologous arteriovenous fistula in a population of patients with end-stage renal disease. Methods The data of 335 consecutive patients with end-stage renal disease who were performed autologous arteriovenous fistula from January 2010 to December 2015 were analyzed retrospectively. The parameters affecting autologous arteriovenous fistula functional maturation were screened. Results Overall arteriovenous fistula functional maturation rate was 78.14%(218/279). The arteriovenous fistula functional maturation rate was 68.33%(82/120) in diabetes and 85.54%(136/159) in non-diabetes, and there was significant difference (χ2=11.844, P<0.01). The arteriovenous fistula functional maturation rate was 62.26%(33/53) in hypoproteinemia and 81.86%(185/226) in non-hypoproteinemia, and there was significant difference (χ2=9.648, P<0.01). Diabetes and hypoproteinemia were the risk factors to promote functional maturation (OR=6.003, 8.476). The arteriovenous fistula functional maturation rate was 87.10%(81/93) in calcium channel blockers using and 73.66%(137/186) in non-calcium channel blockers using, and there was significant difference (χ2=6.556, P<0.05). Calcium channel blockers was the protective factor for promoting functional maturation (OR=0.086). Conclusions Diabetes and hypoproteinemia are found to be associated with functional non-maturation, while calcium channel-blocker agents are associated with better functional maturation.