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Objective:To investigate the differences in applicability of both the portable high-purity germanium (HPGe) γ spectrometer and the portable lanthanum bromide (LaBr) γ spectrometer for measuring thyroid 131I activity and internal exposure monitoring for radiation workers. Method:Both DETECTIVE-DX100-KT portable HPGe γ spectrometer and InSpector 1000 portable LaBr γ spectrometer were used to measure the 131I content in thyroid of radiation workers for comparison of the measuring result, minimum detectable activity (MDA) and corresponding annual committed effective doses between two types of spectrometers. Results:The detection rate of 131I in thyroid of radiation workers was 67.7% for HPGe γ spectrometer and 26.2% for LaBr γ spectrometer, respectively. The MDA was 12.26-14.74 Bq (measuring time: 3-5 min) for HPGe γ spectrometer and 56.56-80.37 Bq for LaBr γ spectrometer (measuring time: 2-4 min). The annual committed effective dose corresponding to MDA was 0.07-0.08 mSv (3-5 min) for HPGe and 0.31-0.45 mSv (2-4 min) for LaBr, respectively, in the case of using chronic continuous intake mode and 7 d monitoring period. Conclusions:The minimum detectable activity (MDA) of the two types of portable spectrometers could meet the requirements specified in GBZ 129-2016 Specifications for individual monitoring of occupational internal exposure for thyroid monitoring equipment. The two types of spectrometers could be used for routine monitoring of internal contamination. The difference between the monitoring result of LaBr γ and HPGe γ spectrometers might be due to such factors as large uncertainty in short measuring time and low activity concentrations, incomplete identical of distance between probe and neck, probe angle setting, different response of equipment to the environment, background deduction method.
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Objective:To ascertain the activity concentration of gross α and β in foods around Fuqing nuclear power plant (NPP) site.Methods:Totally 167 food samples of 25 kinds within 6 categories were collected from the surveillance areas and control areas around Fuqing NPP site. The total radioactivity was analyzed using the food samples. Paired rank sum test was used to determine the influence of the operation of Fuqing NPP on the total radioactivity in foods in surrounding areas. The multiple local rank sum test was used to assess the difference in total radioactivity in different types of foods.Results:The average gross α in poultry meat, vegetables, crops, aquatic products, milk and tea was 0.65, 1.96, 1.41, 3.80, 1.33, 7.67 Bq/kg in surveillance areas and 0.56, 3.24, 2.04, 3.70, 2.24, 9.05 Bq/kg in reference areas, respectively, around Fuqing NPP site. The average gross β (subtracting 40K) in poultry meat, vegetables, crops, aquatic products, milk and tea was 7.0, 10.5, 6.1, 23.5, 24.7, 8.6 Bq/kg in surveillance areas and 7.4, 8.3, 14.5, 22.1, 21.3, 11.0 Bq/kg in reference areas, respectively, around Fuqing NPP site. The Wilcoxon paired rank test showed that there was no significant difference in the gross α and β in foods between surveillance and reference areas around Fuqing NPP site ( P>0.05). The Kruskal-Wallis H test showed that the radioactivity of gross α and β in different foods was statistically significant ( χ2=23.325, 13.918, P<0.05). Conclusions:The increase was not found in total radioactivity in the surrounding foods since the operation of Fuqing NPP in 2015.
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Objective:To explore the assessment methodology for internal dose to workers exposed to 131I radionuclide. Methods:Workers were chosen in a 131I radiopharmaceutial manufacturer and a nuclear medicine department in a hospital using 131I to treat hyperthyroidism and thyroid cancer. A portable high purity germanium (HPGe) gamma spectrometer was used to measure the content of 131I in the thyroid for 4 consecutive times in a period of 7 d. The internal dose was estimated combining with the work rotation mode for workers dealing with 131I. Results:When the monitoring month was used as a typical month to estimate the internal dose, the annual committed effective dose was 0.09-1.93 mSv for the production staff engaged in the repackaging of 131I radiopharmaceuticals in the surveyed enterprise, and 0.06-0.58 mSv for the nuclear medicine staff in the surveyed hospital. After adjusting the monitoring result of the current monitoring period based on the rotation mode, the annual committed effective dose was estimated to be 0.06-1.22 mSv for radiopharmaceutical production workers and 0.03-0.15 mSv for nuclear medicine workers, respectively. Conclusions:In the assessment of internal dose to radiation workers exposed to 131I, using a single time measurement result to estimate the annual dose would lead to a larger error. In the case of continuous monitoring, the result of subsequent monitoring periods should be corrected according to the result of previous monitoring periods. In order to accurately estimate the internal dose of workers exposed to 131I, it is necessary to take full account of the 131I exposure pattern, time and frequency and the internal contamination route. For workers who may be exposed to 131I with potential internal dose greater than 1 mSv/year, a 14 day-routine monitoring period was appropriate.
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Objective:To ascertain the basic situation of radiotherapy in Fujian in 2016.Methods:Based on the unified questionnaire, the types and quantity of radiotherapy and its corollary equipment, the number of radiotherapy staff and the work for quality control were surveyed in the radiotherapy units in the whole province, and the data on patients undergoing radiotherapy and other types of patients were collected from 26 hospitals. The total number of radiotherapy patients in the whole province was estimated by the correlation analysis and multiple linear regression analysis.Results:Radiotherapy was performed in a total of 32 hospitals in Fujian province in 2016. Among them, there were 62 sets of radiotherapy equipment, 33 sets of the simulators, 57 sets of treatment planning systems and 762 workers. The total number of 15 156 radiotherapy patients in 26 hospital were available for the survey. Multiple linear regression models showed that the frequency of application of medical electron accelerator was positively correlated with number of outpatients, emergency patients and inpatients, number of radiotherapy staff, number of electron accelerators ( r=0.311, 0.893, 0.956, P<0.05). Meanwhile, the frequency of aterloading brachytherapy was positively correlated with number of outpatients, emergency patients and inpatients, number of radiotherapy staff, number of aterloading brachytherapy units ( r=0.307, 0.966, 0.988, P<0.05). The frequency of radiotherapy was 0.54 patients per 1 000 population in Fujian in 2016. The delivered dose calibration of accelerators was performed in all hospitals involved in line with the relevant regulations, but the number of quality control equipment for radiotherapy was insufficient, such as the QA beam checker or well-type ionization chamber. Conclusions:In recent years, the rapid development of radiotherapy has been seen in Fujian province. The radiotherapy management should focus on standardenized and improved quality control and regulation in future.
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Objective To estimate the application frequency of X-ray diagnosis in Fujian province in 2016 based on the examination number survey in sampled hospitals in 9 cities.Methods Using the national unified questionnaire and stratified typical sampling method,a total of 43 hospitals in 9 cities of Fujian province were selected for the survey.The survey information mainly contained the basic situation of sampled hospitals and the number of X-ray diagnostic examinees.The basic situation included the numbers of out-patient and emergency care,in-patient,X-ray diagnostic equipment and radiological staff,and the examinees were further classified by examination types,gender,ages and beam positions.Furthermore,based on the survey result,a prediction model of the application frequency of X-ray diagnosis in Fujian province was established,and the frequency in 2016 was also estimated.Results There were 418 sets of X-ray diagnostic equipment,and 1 230 radiological diagnostic staff in the 43 hospitals.The total number of out-patient,emergency care and in-patient was 30 919 162,and the number of X-ray diagnostic examinations was 4 277 518 in the hospitals in 2016.In 2016,the application frequency of X-ray diagnosis in Fujian province was estimated to be 695 examinations per thousand population.Among them,the frequencies of conventional X-ray photography and CT examinations were 373 and 293 examinations per thousand population,respectively.Conclusions Through this survey,the general situation of X-ray diagnostic application in Fujian province in 2016 was grasped,so as to provide reference data for improving the regulations and standards of radiation health protection and strengthening the supervision and management of the application of X-ray diagnostic equipment in Fujian province.
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Audiometer is an important instrument in otolaryngology clinic. Generally, the cost of an audiometer is too much and its function is not powerful. There are many advantages of using a PC as an audiometer. A way is invented to calibrate a PC based virtual audiometer. Discussion about the possibility of adapting a PC based virtual audiometer is stated.