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Objective:To measure the influencing factors associated with the analysis of 226Ra gamma spectra in order to obtain more acurate and precise measuring result on a basis of further optimizing the gamma spectrometry method for 226Ra activity. Methods:A laboratory-based HPGe gamma spectrometer was used to carry out the studies on tracking measurement of sample sealing time, measurement of background fluctuation with lead shielding, analytical method, and selection of characteristic gamma ray energy peak of its daughter nuclides in 226Ra measurement. Results:After the sample was sealed for 12 d, the decay products of 226Ra- 222Rn basically reached equilibrium. The day and night fluctuations of 222Rn in the shielded lead room were obvious but had no obvious regularity. The way of filling nitrogen into the shielded lead room could reduce or avoid the influence of background fluctuations. For 31 soil samples measured after 23 days of sealing, the result of using the efficiency curve method showed that the 226Ra result calculated from the 351.9 keV energy peak were generally higher than the 609.3 keV energy peak, and the higher ratio ranged from 8.0% to 20.7%. The result of relative comparison method showed that the deviation ratio of the two peaks ranged from -4.1 % to 10.3 %. Conclusions:It is recommended to consider the uncertainty attributed from decay equilibrium about 4 % of measured at 12 d after the sample is sealed. When filling nitrogen through the shielded lead chamber to avoid background fluctuations, attention must be paid to the matching relationship between the volume of the lead chamber and the nitrogen filling flow. When the efficiency curve method is used to analyze the activity of 226Ra, the 214Bi ( 609.3 keV ) energy peak has the effect of cascade coincidence addition, so 214Bi(609.3 keV) energy peak should be avoided. When the relative comparison method is used to analyze the activity of 226Ra, both two energy peaks of 214Pb ( 351.9 keV ) and 214Bi ( 609.3 keV ) can be used.
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@#<b>Objective</b> To correct the counting loss of <sup>37</sup>Ar below the activity threshold during the measurement of the absolute activity of the inert radioactive gas <sup>37</sup>Ar using the proportional counter filled with gas. <b>Methods</b> Monte Carlo simulation with Geant4 was performed to establish a proportional counter model and output the energy deposition spectrum of <sup>37</sup>Ar, which were used to simulate and analyze the causes and correction of counting loss. <b>Results</b> The photon detection efficiency was only 38.7% at 60 kPa. The counting loss was mainly caused by the wall effect produced by the photons, which could be reduced by increasing the gas pressure and corrected by extrapolation. The influence of wall effect at 100 kPa was 4.4%, and the deviation between simulation and experiment was < 0.6%. <b>Conclusion</b> A factor could be calculated by Geant4 simulation for the correction of counting loss, thus achieving the accurate measurement of <sup>37</sup>Ar activity by proportional counter.
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Objective@#To prove the validity and accuracy of the digitizer instead of the conventional electronics plug-in for radionuclide measurement.@*Methods@# Based on a large-area flow-gas multi-wire proportional counter for 2πα and 2πβ surface particle emission rate measurement, the DT5730 digital waveform sampler developed by CAEN was used for waveform signal acquisition, amplitude analysis, and data processing of the α-plane source 241Am and the β-plane source nuclides 14C, 36Cl, and 90Sr-90Y of different energies.@*Results@#The deviations between the α and β surface particle emission rate results obtained after dead time and background corrections and the measurements obtained based on the plug-in calibrator were all within 0.6%, within the uncertainty range, under consistent experimental conditions such as electronics threshold and high pressure.@*Conclusion@#The digitizer is an effective alternative to conventional electronics plug-ins for α and β signal acquisition and processing and the accurate measurement of α and β emission rates.
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Objective To investigate the current situation of radiological health technical service institutions and their technical services in China, and to provide a basis for better utilizing radiological health technical service resources and strengthening institutions’ capability building. Methods From October to December 2021, we conducted quality monitoring, ability comparison, capability building surveys, and other investigations on radiation health technical services to collect information on the qualifications and technical services of radiation health service institutions. The data were pooled and analyzed using SPSS software. Results By the end of 2021, there were 608 radiological health technical service institutions across China, with 47.0% of them located in the eastern region, and the percentage of institutions in the health system (42.6%) was less than that in the non-health system (57.4%). Institutions of grade A offered 62.3% of technical services, while institutions of grade B provided 37.7% of technical services; technical services provided by the non-health system and the health system accounted for 84.2% and 15.8%, respectively; institutions in the health system at the province, prefecture, and county levels offered 37.1%, 50.6%, and 12.3% of technical services, respectively. Conclusion In recent years, the proportion of institutions in the non-health system has increased significantly, but the proportion of institutions in the health system with radiological health qualifications is small, and the development is uneven in the numbers of institutions, technical services, and professional and technical personnel in the eastern, central, and western regions and at the province, prefecture, and county levels in China. It is necessary to further encourage and support health system institutions in strengthening capability building and applying for radiological health qualifications, and to increase construction and investment in the western region and at the district/county levels, in order to improve the overall capability and level of radiological health technical services in the country.
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In case of accidental exposure, a rapid assessment of radiation dose is of great significance for taking timely countermeasures. Finding an alternative portable emergency dosimeter is crucial for people who have been exposed to accidental radiation but are not equipped with a personal dosimeter. In addition, the real-time monitoring of radiation dose level in the normal environment can meet the needs of the public to know their health status in time. Thus, the portability and intelligence of mobile phones attract researchers to carry out related work. This article reviews the research progress in individual exposure dose estimation and monitoring based on mobile phones.
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Objective To optimize the Marinelli beaker with the simulation of Laboratory Sourceless Object Calibration Software (LabSOCS), to investigate the detection efficiency of HPGe detector in measuring noble gas, and to provide a reference for the measurement and optimization of noble gas effluent from nuclear power plants. Methods LabSOCS was used to establish a Marinelli beaker model to investigate the relationship of gamma ray detection efficiency of noble gas with gas components, gas density, size and volume of the Marinelli beaker, and the shape of source container. Results The gas components had little effect on the detection efficiency of the noble gas in the Marinelli beaker. The gas density had a relatively great effect on the detection efficiency of low-energy gamma ray. The Marinelli beaker of appropriate height and radius enabled the HPGe detector to get better measurement results. For the BE5030 HPGe detector, the highest detection efficiency of the Marinelli beakers of different volumes were observed at the location where the radius/height ratio was 0.7, and the optimal values of height and radius were given for the Marinelli beakers of different volumes. Conclusion Choosing Marinelli beaker of the appropriate size can improve the detection efficiency of noble gas in the effluent from nuclear power plants.
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Objective:To investigate 131I activity in thyroid of workers at the place of radioiodine therapy and its main influencing factors. Methods:In terms of the types of hospitals, six hospitals that performed radioiodine therapy procedure were selected by quota sampling in the provinces of Shandong and Shanxi. 131I activity in thyroids of 76 workers at the place of radioiodine therapy was measured directly, and their internal doses were estimated. Results:131I activity in thyroids was found to be above the detection limit for 29 subjects (38.16%) in five hospitals. The maximum value of 131I activity was 2 468.45 Bq for a doctor who was responsible for manual distribution of radioisotopes. In general 131I activities in thyroid of workers at the place of radioiodine therapy of six hospitals were not significantly different ( P>0.05). But the measurement result in the hospitals where radioiodine was distributed manually were significantly higher than that in the hospitals where radioiodine was distributed automatically ( Z=1.75, P<0.01). Thyroid measurement result of 12 workers in two hospitals where radioiodine was distributed manually were all above the detection limit, with medians of 324.59 Bq and 331.98 Bq, respectively. The medians of 131I activities in thyroid of 12 staff in the remaining 4 hospitals were all below the detection limit. The detection frequencies of 131I above dose limit were 32.61%, 25.00%, 10.00% and 0. The measurement result for the doctors who participated in distributing 131I and the relevent cleaners were significantly higher than for the doctors who did not participate in distributing 131I at the same hospital ( Z=2.44, 2.12, P<0.05). Conclusions:There was a significant difference in the internal exposure level among workers at the different places of radioiodine therapy. Using automatic loading device could reduce the internal exposure level of the workers at the place of radioiodine therapy. It is necessary to strengthen the radiological protection for workers at the control area of the place of radioiodine therapy.
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Objective@#To explore the effect of change in occupational internal dose coefficients on estimation of the in- ternal exposure dose of radiation workers.@*Methods@#Forty-one radionuclides were selected as the research objects, and their new and old occupational internal dose coefficients were summarized. The change in internal dose coefficients was analyzed by calculating the ratios of dose coefficients and using the frequency distribution of ratios.@*Results@#The occupational in- ternal dose coefficients of the 41 radionuclides analyzed had all changed, with ratios ranging from 0.1 to 4.5, and the maxim- um difference reaching 10 times (when the ratio was equal to 0.1).@*Conclusion@#It is recommended to revise the national standards concerning occupational internal dose coefficients in time and update the occupational internal dose coefficients, so as to better monitor the occupational health of radiation workers.
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@#<b>Objective</b> To discuss the selection of dose estimation methods for internal exposure to tritium, their applicable working scenarios, and accurate dose estimation. <b>Methods</b> We compared the process and formula of two methods of urine tritium concentration monitoring in estimating the committed effective dose, explained the limitations of the atmospheric tritium concentration monitoring method, and compared the three methods from the aspects of the application scope and measurement methods. <b>Results</b> The atmospheric tritium concentration monitoring and urine tritium concentration monitoring methods provided opposite results of the magnitude of the committed effective doses for persons 3 and 10. The mean of the absolute values of the percentages by which <i>E</i>(<i>τ</i>)<sub>1 </sub>values were higher than <i>E</i>(<i>τ</i>)<sub>3 </sub>values was 29.6%, and that of <i>E</i>(<i>τ</i>)<sub>2</sub> higher than <i>E</i>(<i>τ</i>)<sub>3 </sub>was 72.4%. The consistency between the reference man-based tritium dose estimation method and the atmospheric tritium concentration monitoring method was better. The atmospheric tritium concentration monitoring method tended to underestimate the committed effective dose of tritium. <b>Conclusion</b> We suggest urine tritium concentration monitoring for estimating the committed effective dose, rather than atmospheric tritium concentration monitoring. The use of the reference man-based tritium dose estimation method or urine tritium activity concentration integration method should be based on individual metabolic conditions, working environment, and intake time, and urine sampling should be on time and repeated for monitoring..
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Objective The effect of sieved particle size and equilibration time of soil samples on the measurement of radionuclides was studied to improve the accuracy of the specific activity of radionuclides in soil samples measured by gamma spectrometer. Methods The collected soil samples were dried and divided into four parts. After sieved with width of the mesh 2.0 mm, 1.0 mm, 0.5 mm and 0.25 mm respectively, they were filled into sample containers and sealed. The activity concentrations of 226Ra, 210Pb, 228Ra, 40K and 137Cs in different sieved soil samples were then measured at the sealed interval of 0, 4, 8, 12, 16, 21, 25 and 29 days by HPGe gamma-ray spectrometry respectively. Results The coefficients of variation ofthe specific activities of 226Ra, 210Pb, and 228Ra in soil samples measured at different equilibration intervals range from 0.9% to 4.3%. The coefficients of variation of the specific activities of 226Ra, 210Pb, 228Ra, 40K and 137Cs in soil samples with different sieved particle sizes range from 3.7% to 14.1%. Conclusion When the specific activities of radionuclides are determined by gamma-ray spectrometer, the effect of the sieved particle size on the measurement result must be considered, and its impact is higher than the equilibration time. This study is very useful for improving the accuracy of the determination of radionuclides in soil sample using gamma-ray spectrometer.
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Since the Chernobyl nuclear accident, the radioactive contamination in food caused by the nuclear accident has been widely concerned by people. There have been a lot of studies on concentrated radionuclides in mushrooms in foreign countries, but the research on radionuclides content and transfer distribution mechanism of radionuclides in mushrooms is almost blank in China. Studies have shown that mushrooms have a strong adsorption capacity on radionuclides. As a common food in daily life, therefore, it is of great significance to study the content of radionuclides in mushrooms for evaluating the internal dose in the human body. In this paper, the types of radionuclides in mushrooms and the methods of their transfer and distribution in mushrooms were reviewed, and the research status and development trends at domestic and abroad in recent years were emphasized, in order to provide theoretical support for the future basic research.
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Objective To apply InSpector 1000 portable γ spectrometer and its corresponding supporting software to the monitoring of thyroid 131I activity of radiation workers, and to estimate the internal radiation dose of medical staff in nuclear medicine department. Methods The spectrometer was calibrated and taken to participate in the 2018 thyroid radioactive iodine intercomparison program initiated by Lawrence Livermore National Laboratory in the United States to ensure the accuracy of the measurement; the spectrometer was used to measure 131I activity ofthe radiation workers of the nuclear medicine departments of two grade-A tertiary hospitals in Beijing and Jinan to verify the feasibility of the method. Results The InSpector 1000 portable γ spectrometer was qualified for international intercomparison. Measurement results from the grade-A tertiary hospital in Beijing showed that the thyroid 131I activity of each of 10 radiation workers was below the detection limit (33.30 Bq). Measurement results from the grade-A tertiary hospital in Jinan showed that the thyroid 131I activities of the 4 radiation workers were 64.05 Bq, 160.77 Bq, 416.67 Bq, below the detection limit (35.18 Bq) respectively, and of 3 of the 4 subjects 131I was detected in the thyroid, and their corresponding thyroid accumulative organ doses were 0.70 μSv, 1.77 μSv, and 4.58 μSv, respectively. Conclusion InSpector 1000 portable γ spectrometer has a strong feasibility for thyroid 131I monitoring of radiation workers in nuclear medicine. The spectrometer has a good application prospect in the field of radiation monitoring, and can play an important role in the field of radiation protection and nuclear emergency detection.
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A 57-year-old male patient was referred to our department with complaints of his right adrenal gland occupancy and hypertension about 6 months. When admitted to the hospital, the blood pressure was about 160/100 mmHg, and the heart rate was 110 beats/min. He was no obvious obesity, acne, abnormal mood, without weakness of limbs, acral numbness, palpitation and headache. He presented with type 2 diabetes for more than 3 years, with oral administration of metformin enteric coated tablets and subcutaneous injection of insulin glargine to control blood glucose, and satisfied with blood glucose control. Enhanced CT showed that: the right adrenal gland showed a kind of oval isodense, slightly hypodense shadow, the edge was clear, lobular change, the size was about 5.8 cm×5.4 cm, uneven density, there were nodular and strip calcification, round lipid containing area and strip low density area, and the CT value of solid part was about 34 HU. Enhanced scan showed heterogeneous nodular enhancement in the solid part of the right adrenal gland, nodular enhancement could be seen inside. The CT values of solid part in arterial phase, venous phase and delayed phase were 45 HU, 50 HU and 81 HU, respectively. Considering from the right adrenal gland, cortical cancer was more likely. No obvious abnormality was found in his endocrine examination. After adequate preoperative preparation, retroperitoneal laparoscopic adrenalectomy was performed under general anesthesia. During the operation, the 6 cm adrenal tumor was closely related to the inferior vena cava and liver, and after careful separation, the tumor was completely removed and normal adrenal tissue was preserved. The operation lasted 180 min and the blood loss was 100 mL, and the blood pressure was stable during and after the operation. There was no obvious complication. The results of pathological examinations were as follows: the size of the tumor was 7.5 cm×6.0 cm×3.5 cm, soft, with intact capsule and grayish-red cystic in section. Pathological diagnosis: (right adrenal gland) cavernous hemangioma, secondary intravascular thrombosis, old hemorrhagic infarction with calcification and ossification. After 6 months of observation, no obvious complications and tumor recurrence were found. In summary, cavernous hemangioma of adrenal gland is a rare histopathological change. Its essence is a malformed vascular mass. Blood retention is the cause of thrombosis and calcification in malformed vessels. The imaging findings were inhomogeneous enhancement of soft tissue masses, and the adrenal function examination showed no obvious abnormalities. Retroperitoneal laparoscopic surgery is feasible after adequate preoperative preparation. It is difficult to diagnose the disease preoperatively and needs to be confirmed by postoperative pathology.
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Humans , Male , Middle Aged , Adrenal Gland Neoplasms/surgery , Adrenalectomy , Diabetes Mellitus, Type 2 , Hemangioma, Cavernous/surgery , Laparoscopy , Neoplasm Recurrence, LocalABSTRACT
Objective:To improve the radionuclide measurement technology by γ-spectrometry throuth a review of the intercomparisons between China and Japan results over the past 20 years.Methods:Before the beginning of each intercomparison, one of participating laboratories was agreed to be responsible for preparing the samples for the intercomparison. By intercomparison of the measurement results arnong the laboratories some potential problems during the sample pre-trement or analysis were found and solved.Results:The intercomparisons had been carried out for 11 times over the past 20 years. Totally 290 measured and analyzed results had been obtained from 20 samples of six categories. The proportion 95.5% of measurement results were in agreement with each other within the deviation range.Conclusions:The measuring and analytical capability of the laboratories involved were tested. The intercomparisons also provide long-term quality assurance measures for the radionuclide measurement and analysis in each laboratory.
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Objective@#To standardize the operation and data processing in radiological health institutions in China, in order to promote the assessment of γ-spectrometry, improve the measurement and analysis capabilities of each laboratory, and accordingly improve accuracy of environment sample measuring.@*Methods@#By collecting the values of 232Th, 40K and 137Cs contents in soil samples from 2015 to 2017, the assessment results of γ-spectrometry laboratores were summarized and analyzed.@*Results@#The technical institutions from 25 provinces were involved in the assessment until 2017, including disease control and prevention centers, entry-exit inspection and quarantine agencies, research institutes, universities and companies. The number of participants was increased from 40 to 48, and the qualified rate exceeded 90%, and the excellent rate was no less than 11% each year. The percentage of relative deviation less than 10% between the measuring result of 232Th, 40K and 137Cs contents and the reference value was larger than 80% in 2017. The accuracy became better. However, the number of institutions with U and Z score less than 1 was increased from 11 to 25, suggesting that the precision of measuring result has also been greatly improved.@*Conclusions@#Radiological health institutions in China have good measurement and analysis capabilities with regard to γ-spectrometry, which can meet the needs of environmental sample measurement and in-food radionuclide risk monitoring in an emergency of nuclear and radiation. But a few institutions′ measuring results were largely different from the reference values, as a consequence, it is important to strengthen their ability of measurement and analysis.
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Objective@#To establish a nationwide food radionuclides monitoring network to improve the national food radionuclides monitoring efficiency.@*Methods@#The system includes a nationwide food radionuclides monitoring information system based on the existing National Radiation Health Information Platform. The system consists mainly of information filling, data review, retrieval query, graphic report and data export.@*Results@#Since 2016, a network submission method was used for the first time in the national food radioactive material risk monitoring. The system improved the timeliness and validity of data reporting and provided a more effective means than before for the normative management and scientific application of data.@*Conclusions@#The national food radionuclides monitoring network was successfully constructed and in use. The system has provided a good information support for monitoring the food radionuclide levels in China.
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Objective To standardize the operation and data processing in radiological health institutions in China, in order to promote the assessment of γ-spectrometry, improve the measurement and analysis capabilities of each laboratory, and accordingly improve accuracy of environment sample measuring. Methods By collecting the values of 232 Th, 40 K and 137 Cs contents in soil samples from 2015 to 2017, the assessment results of γ-spectrometry laboratores were summarized and analyzed. Results The technical institutions from 25 provinces were involved in the assessment until 2017, including disease control and prevention centers, entry-exit inspection and quarantine agencies, research institutes, universities and companies. The number of participants was increased from 40 to 48, and the qualified rate exceeded 90％, and the excellent rate was no less than 11％ each year. The percentage of relative deviation less than 10％ between the measuring result of 232 Th, 40 K and 137 Cs contents and the reference value was larger than 80％ in 2017. The accuracy became better. However, the number of institutions with U and Z score less than 1 was increased from 11 to 25, suggesting that the precision of measuring result has also been greatly improved. Conclusions Radiological health institutions in China have good measurement and analysis capabilities with regard to γ-spectrometry, which can meet the needs of environmental sample measurement and in-food radionuclide risk monitoring in an emergency of nuclear and radiation. But a few institutions′ measuring results were largely different from the reference values, as a consequence, it is important to strengthen their ability of measurement and analysis.
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Objective To establish a nationwide food radionuclides monitoring network to improve the national food radionuclides monitoring efficiency. Methods The system includes a nationwide food radionuclides monitoring information system based on the existing National Radiation Health Information Platform. The system consists mainly of information filling, data review, retrieval query, graphic report and data export. Results Since 2016, a network submission method was used for the first time in the national food radioactive material risk monitoring. The system improved the timeliness and validity of data reporting and provided a more effective means than before for the normative management and scientific application of data. Conclusions The national food radionuclides monitoring network was successfully constructed and in use. The system has provided a good information support for monitoring the food radionuclide levels in China.
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Objective To study the variation in net count rates of natural radionuclides in background of gamma-ray spectrometer,so as to provide a scientific basis for reducing the effect of background fluctuations on sample measurement.Methods The unscheduled background spectrum obtained using two high-purity gamma-ray spectrometers during 2013-2017 were collected,and then the net count rates of 210pb,234Th,212Pb,214pb,208Tl,214Bi,228Ac and 40K were calculated and analyzed by aid of statistical method.Results There was a significant difference in the net count rates of 210Pb,234Th,212Pb,214Pb,208Tl,214Bi,228Ac and 40K in the background spectrum of gamma-ray spectrometer,and the net count rates of 214Pb,214Bi and 40K was significantly higher than those of 210Pb,234Th,212pb,208Tl and 228Ac.There were no significant differences in the net count rates of these eight natural radionuclides from 2013 to 2017,respectively (P ＞ O.05).However,the coefficients of variation in the net count rates for 214pb and 214Bi were both greater than 50％.Conclusions When the activity concentration of natural radionuclides is determined in a sample by gamma-ray spectrometer,it is critical to subtract the background spectrum obtained recently to ensure the accuracy of the measurement,especially for the low activity concentration of natural radionuclide to be measured.
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Objective To validate the effect of the Laboratory Sourceless Calibration Software (LabSOCS) in the actual sample measurement,and to study the effect of sample self-absorption correction and cascade radiation coincidence correction.Methods Two standard samples from the analytics company were measured using the two gamma spectrometers at our laboratory.The result were calculated using the efficiency generated by LabSOCS.Calculated result of each nuclide were analyzed.Results were compared with the standard value provided in the certificate.Results The LabSOCS may solve the problem of sample self-absorption correction in gamma energy spectrum measurement and analysis.The maximum deviation between the values of 241Am and 109Cd analyzed by LabSOCS and the reference value was less than 4％ for the broad-energy high-purity germanium gamma-ray spectrometers.However,the coincidence additive correction caused by cascade radiation could not be solved directly.Conclusions The research shows that the LabSOCS can solve the problem of sample self-absorption correction by describing the composition and density of the samples accurately.However,when analyzing the nuclides with cascade radiation,the coincidence addition effects should be considered.The flexible simulation method of the LabSOCS can be used to increase the distance from the cascade nuclide sample to the detector and to complete the accurate measurement of the cascade nuclide.