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Objective To improve the analysis of 134Cs, 137Cs, and 60Co in aerosol samples by the national key radiation environment laboratories. Methods Intercomparison of analysis results of 134Cs, 137Cs, and 60Co in standard aerosol samples was performed among the national key radiation environment laboratories according to Gamma spectrometry method of analyzing radionuclides in biological samples (GB/T 16145-1995 ), and the intercomparison results were evaluated by the standard deviation. Results Six laboratories were involved in the intercomparison. For 134Cs, 50% of the laboratories showed a relative deviation less than 10%, and 50% showed a relative deviation of 10%-20%. For 137Cs, 33.3% of the laboratories showed a relative deviation less than 10%, and 76.7% showed a relative deviation of 10%-20%. For 60Cs, all laboratories showed a relative deviation less than 10%. The overall intercomparison results were acceptable. Conclusion The laboratories in this intercomparison show generally good results.
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Background Individual monitoring of occupational external exposure is an essential part of the occupational health management of radiation workers, and is an important basis for the evaluation of individual absorbed dose and the diagnosis of occupational radiation diseases. Continuous participation of monitoring service providers in intercomparison is a fundamental quality assurance for routine monitoring, which can identify problems and improve them in time. Objective Taking the Laboratory of Radiation Protection in Shanghai Institute of Preventive Medicine as an example, to evaluate the performance of an individual occupational external dose monitoring system in the laboratory, identify influencing factors of the monitoring results, and provide a basis for improving the quality of daily monitoring by analyzing the process and results of a national intercomparison of individual dose monitoring. Methods According to the Testing criteria of personnel dosimetry performance for external exposure (GBZ 207-2016), and the relevant requirements of Class II (photon) inspection, a total of 20 groups of blind sample dosimeters were measured for four consecutive years from 2018 to 2021. The radiation energy source of each group was identified, and related personal dose equivalent Hp(10), the uncertainty of measurement results, and the deviation between the reported value and the reference value were calculated. The national intercomparison process and results of individual dose monitoring were also analyzed. Results The energy sources of the blind samples in the tested laboratory for four years were N100 or Cs-137. The reported dose values of the blind samples were 0.57-4.61 mSv, the combined uncertainties were 0.043-0.365 mSv, the expanded uncertainties (k=2) were 0.09-0.73 mSv, and the relative expanded uncertainties (k=2) were 13.8%-16.4%. The single-group performance ∣Pi∣ of 20 sets of blind samples in the four years was ≤0.10, the yearly comprehensive performance of 5 sets of blind samples was ≤0.10, and the yearly Q score of the test report was >15 points. The laboratory achieved excellent results in the national intercomparison of individual dose monitoring in four consecutive years, except the Q value not reaching full score. Conclusion The laboratory exhibits standardized data processing of individual dose monitoring, generates accurate and reliable results, and meets the requirements of relevant national standards; but it should continue to participate in the national intercomparison of individual dose monitoring, strengthen the angular response research of energy identified dosimeter, improve the monitoring ability of low-dose X-rays, analyze the key points of reducing the uncertainty of measurement results, and continuously improve the monitoring ability.
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@#<b>Objective</b> To analyze the process of intercomparison of national personal dose monitoring, evaluate the ability of personal dose monitoring, and ensure the accuracy and reliability of monitoring results in our laboratory. <b>Methods</b> In accordance with the intercomparison protocol for 2019—2021, an energy-discriminant thermoluminescence dosimeter was used for measurement at different doses. The uncertainty of measurement was evaluated and compared with the reference value. <b>Results</b> <i>H</i><sub>p</sub>(10) was measured for intercomparison in 2019—2021. In 2019, the single group performance difference was −0.02 to 0.02 and the comprehensive performance was 0.02. These values were 0.02-0.10 and 0.05 in 2020, and −0.02 to 0.02 and 0.01 in 2021. The intercomparison results were rated as excellent in the three consecutive years. <b>Conclusion</b> The personal dose monitoring system in our laboratory was in good condition, and the monitoring results were accurate and reliable. Improving the knowledge of personnel and cultivating a serious working attitude are important for intercomparison and personal dose monitoring.
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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 In order to test and improve the monitoring technical level and ability of radiation environmental monitoring network in Zhejiang Province, ensure the accuracy and reliability of monitoring data and information, and obtain the cosmic ray response values of instruments and equipment in this year. Methods In September 2018，an intercomparison meeting of environmental gamma radiation air absorbed dose rate within the radiation environmental monitoring network of Zhejiang province was held in Ningbo，which was organized by Zhejiang Province Radiation Environmental Monitoring Center.A total of 33 sets of instruments from 15 member units participated in the intercomparison measurements at 5 environmental measuring points, and the comparison results were evaluated by the Z score values. Results It was found that the |Z| of all measurement results were less than or equal to 2, and the evaluation results were satisfactory and acceptable. Conclusion The measured data of scintillation counters have relatively wider dispersion，and the high pressure ionization chambers have bigger response valuetocosmic ray. The measurement results of the two kinds of instruments keep a good linearity except for the measurement points of cosmic ray response.
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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 analyze the specific activity of radionuclides based on laboratory intercomparison.Methods Intercomparison of the measurements of radioanuclides 232Th,40K and 137Cs in soil samples,organized by National Institute for Radiological Protection,China CDC,was conducted using HPGe γ-spectrometry and the method of relative comparison and efficiency curve,respectively.Results The relative deviations were all less than 5％compared to the reference values in the conditions of both relative comparison method and efficiency curve method used,respectively.The relative deviations to the reference values were less than 4％for the relative comparison method.Conclusions Both the relative comparison method and the efficiency curve method can be used to measure the activity of radionuclides in the intercomparison samples,and the latter is superior to the former.
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Objective To increase the cumulative measurement level of 222 Rn and 220 Rn and ensure the accuracy and reliability of the measurement result . Methods By using improved 222 Rn-220 Rn discriminative detectors ( LD-P detectors) , the radon research group of National Institute for Radiological Protection Chinese Center for Disease Control and Prevention participated with the intercomparison organized by National Institute of Radiological Science ( NIRS) , Japan. Specifically, with the 222 Rn-220 Rn discriminative detectors being sent to Japan, the comparison was completed under different conditions in the 222 Rn chamber and 220 Rn chamber in NIRS. After exposure, the detectors were sent back to our laboratory for etching and analysis, and then measurement result were informed to NIRS. Finally, NIRS returned the exposure reference values of 222 Rn and 220 Rn to our laboratory. Results Under the conditions of high and low levels of 222 Rn, the relative percentage differences ( RPD ) between the measured values and the reference value provided by the NIRS were -12. 0％ and -11. 8％, respectively, while coefficients of variation ( COV) were 3. 0％ and 6. 2％, respectively. Under the conditions of high level and low levels of 220Rn, the relative percentage differences (RPD) between the measured value and the reference value provided by the NIRS were -0. 8％ and -8. 0％, respectively; coefficients of variation ( COV ) were 6. 7％ and 4. 5％, respectively. Conclusions This intercomparison result were categorized by NIRS ( PRD<10％) , with the satisfactory result of LD-P detectors available.
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Objective To improve theγ-spectrometry analysis technology in water sample through the intercomparison conducted among the key laboratories. Methods To take part in the intercomparison of γ-spectrometry analysis in water sample organized by National Institute of Metrology ( NIM ) , the radionuclides of 238 U,226 Ra, 208 Tl, 228 Ac, 40 K, 241 Am, 137 Cs, and 60 Co in water sample were determined. The efficiency of the detector was calibrated renewedly by new standard source in 2015 and a new γ-spectrometry (BE5030) was used for sample measurement. Results Analysis and comparison of the three measurement results and the leading laboratory reference values showed that the results measured by γ-spectrometry ( BE5030 ) were better, especially for the natural radionuclides. The maximum En value between them and NIM reference value was only 0. 71. Conclusions The wide range energy γ-spectrometry (BE5030) has obvious advantages in the measurement and analysis of natural radionuclides. Due to the special structure of the wide range energy detector, its background interference is less in low energy area. This inter-comparison improved the accuracy of sample measurements and analysis, with good result achieved.
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Objective To improve theγ-spectrometry analysis technology in water sample through the intercomparison conducted among the key laboratories. Methods To take part in the intercomparison of γ-spectrometry analysis in water sample organized by National Institute of Metrology ( NIM ) , the radionuclides of 238 U,226 Ra, 208 Tl, 228 Ac, 40 K, 241 Am, 137 Cs, and 60 Co in water sample were determined. The efficiency of the detector was calibrated renewedly by new standard source in 2015 and a new γ-spectrometry (BE5030) was used for sample measurement. Results Analysis and comparison of the three measurement results and the leading laboratory reference values showed that the results measured by γ-spectrometry ( BE5030 ) were better, especially for the natural radionuclides. The maximum En value between them and NIM reference value was only 0. 71. Conclusions The wide range energy γ-spectrometry (BE5030) has obvious advantages in the measurement and analysis of natural radionuclides. Due to the special structure of the wide range energy detector, its background interference is less in low energy area. This inter-comparison improved the accuracy of sample measurements and analysis, with good result achieved.
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Objective To guarantee the quality of measurenents with the radon-thoron discriminative detectors of our laboratory.Methods LD-P radon-thoron discriminative detector participated in the international intercomparison for integrating radon/thoron detectors organized by National Institute of Radiological Science (NIRS,Japan).Detectors were sent to NIRS for exposure.Radon intercomparison was conducted with radon chamber providing three levels of exposure:low,medium and high levels.Thoron intercomparison was carried out at thoron chamber,which also provided three levels of exposure:low,medium and high levels.Detectors were posted back to our laboratory for etching and analysis after exposure.Then the measured values were submitted to NIRS.Finally the reference values were informed of us.Results The relative percent difference (RPD) between the measured value and the reference value for radon was-13.8％,-14.4％ and-17.1％ at low,medium and high levels respectively,and that of thoron were-14.4％,8.9％ and-3.2％ at three levels respectively.Conclusions Both radon and thoron measurement of our detectors rank asCategory Ⅰ in the 4th international intercomparisons for integrating radon/thoron detectors with the NIRS radon/thoron chambers.
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Intercomparison is an important tool for quality assessment, because equipment performance and procedures are evaluated and compared. In nuclear medicine, this tool is wide utilized to evaluate the ability of the services to measure activities of radiopharmaceuticals which will be administered to the patients in diagnostic or therapeutic procedures. In this work, a comparison program of activity measurements of the 99mTc, 131I, 67Ga and 201Tl radionuclides was established in Pernambuco State, at the Brazilian Northeast, with the aim of evaluating the quality of routine measurements carried out in the NMS. The results in each NMS are sent to the Standard laboratory, which compares these results with the acceptance limits recommended by national regulations. All NMS participants complied with the limit established for the accuracy of measurement (+/-10 percent) and showed that their radionuclide calibrators are adequate for measurement of the activities of radiopharmaceuticals.
A intercomparação é uma importante ferramenta para avaliação da qualidade da medição da atividade de radiofármaco, porque não apenas o desempenho do equipamento é verificado, mas também todo procedimento de medição. Na medicina nuclear, esta ferramenta é amplamente utilizada para avaliar a habilidade dos serviços de medicina nuclear (SMN) na medição da atividade dos radiofármacos que serão administrados aos pacientes para diagnósticos ou procedimentos terapêuticos. Neste trabalho, um programa de intercomparação de medidas de atividades de radiofármacos, utilizando as fontes de 99mTc, 131I, 67Ga e 201Tl, foi estabelecido no estado de Pernambuco, região nordeste do Brasil, com o objetivo de avaliar a qualidade das medições realizadas nos SMN. Os resultados obtidos em cada SMN são enviados ao laboratório padrão, que os compara com os valores de referência recomendados pela norma nacional, verificando o desempenho destes instrumentos. Todos os SMN participantes respeitaram os limites estabelecidos para a exatidão das medidas (+/-10 por cento), demonstrando que os calibradores de radionuclídeos estão adequados/apropriados para a medição de atividades de radiofármacos.
Subject(s)
Humans , Quality Control , Nuclear Medicine/standards , Iodine Radioisotopes/standards , Technetium/standards , Brazil , Calibration , Reference StandardsABSTRACT
Objective To assess the accuracy and precision of γ-spectrometry analysis, and to obtain accurate and valid measurement results in the middle term and long term. Methods A nationwide intercomparison on gamma-ray spectrometry measurement of activity concentration of 226Ra, 232Th and 40K in soil and building material was organized by National Institute for Radiological Protection( NIRP) , China CDC. Results 15 laboratories participated in this intercomparison, with 13 laboratories produced acceptable results. Only 2 laboratories were classified as " not acceptable" , including one for inappropriate accuracy in determination of 40K and another for inappropriate precision determination of 226Ra in both kinds of the samples. Through comment and discussion, the second round intercomparison got satisfactory results. Conclusions The overall measurement results of samples for intercomparison are in close agreement with the reference values. Most of the laboratories involved in the intercomparison have good ability in γ-spectrometry analysis.