Measurement of 239Pu in fecal samples based on inductively coupled plasma-mass spectrometry / 中国辐射卫生

Objective To establish a method for measurement of 239Pu in fecal samples based on inductively coupled plasma-mass spectrometry (ICP-MS), and to provide a novel method for assessing the internal exposure of workers. Methods Fecal samples were collected from workers and labeled. The samples were pretreated with carbonization ashing and microwave digestion devices, purified on TEVA resin, and measured using ICP-MS. Results The detection limit of 239Pu in fecal samples based on ICP-MS was 1.91 × 10−4 Bq. Conclusion In the routine monitoring of class S substances characterized by a 5 μm aerodynamic diameter during 12 months, the committed effective dose corresponding to the detection limit is 0.17 mSv. This value meets the requirements of relevant national standards and ICP-MS can be used as a novel means for accurate evaluation of internal exposure for workers.

Study on serum perfluoroalkyl and polyfluoroalkyl substances exposure status of community residents in Songjiang District， Shanghai / 上海预防医学

ObjectiveTo investigate the characteristics of serum perfluoroalkyl substances （PFASs） exposure and potential influencing factors among community residents in Songjiang District， Shanghai. MethodsIn August 2021， residents who underwent routine health checkups in a community in Songjiang District， Shanghai were recruited as study subjects. The inclusion criteria were adult residents who had lived in the area for more than 3 years， had no occupational exposure history， no underlying diseases， were not pregnant， and were able to complete the questionnaire independently and sign the informed consent form. A questionnaire survey was conducted and venous blood samples were collected. The concentrations of 15 PFASs in serum were determined using ultra-high performance liquid chromatography-tandem quadrupole mass spectrometry （UPLC-MS/MS）. Ordered multi-class logistic regression， interquartile range （IQR）， and odds ratio （OR） were used to explore the influencing factors and risk magnitude of serum PFASs concentrations. ResultsOf the 15 PFASs， 14 were detected， and the detection rates of 7 PFASs were higher than 50%. The highest detected concentrations among the PFASs were PFOS （perfluorooctane sulfonate）， PFOA （perfluorooctanoic acid）， and PFHxS （perfluorohexane sulfonate）， with median concentrations of 48.61 μg∙L-1， 37.29 μg∙L-1， and 36.51 μg∙L-1， respectively. The strongest correlation was between PFDA and PFUnDA （r=0.93， P<0.05）， followed by PFOS and PFDA （r=0.86， P<0.05）. Age， frequency of plastic product use， time spent indoors per day， personal annual income， tea consumption， and daily water intake were potential factors for exposure to PFASs. Among them， age was positively correlated with PFASs； tea consumption was positively correlated with PFNA and PFOA； PFHpA was negatively correlated with the frequency of plastic product use and personal annual income； and PFOS was negatively correlated with the time spent indoors per day. ConclusionThe exposure to serum PFASs among community residents in Songjiang District was relatively serious， and the main components were traditional PFOA， PFOS， and PFHx. Different sociodemographic characteristics had varying degrees of influence on the concentrations of PFASs in serum. The impact of PFASs exposure on the health of community residents deserves further investigation.

Determination and analysis of monitoring period and measuring duration of personal internal exposure dose / 中国辐射卫生

Objective To develop a reasonable plan of monitoring personal internal exposure dose. Methods This paper introduced the methods of monitoring the individual dose and direct measurement of three representative radionuclides. Results The maximum monitoring periods were determined according to the radionuclide retention characteristics and the reporting standards and requirements, which were m(1)/m(T/2) ≤ 3 and m(T/2)/m(T) ≤ 3. The lower detection limit of the instrument was derived from the monitoring periods and the annual radionuclide intake limit, which should be lower than the derived method detection limit of the corresponding radionuclide. Then the measuring duration of the instrument that meets the corresponding conditions was derived from the derived method detection limit of the instrument and the maximum monitoring period. Conclusion Our results provide a reference for the formulation of a plan of monitoring personal internal exposure dose.

Assessment of americium retention in bone by measuring 241Am in the skull with a whole-body counter / 中国辐射卫生

Objective To assess the retention of 241Am in the whole-body bone of worker by measuring the retention of 241Am in the skull. Methods A whole-body counter with high-purity germanium detector was used to measure the 59.5 keV full-energy peak count of 241Am in the skull. The efficiency of the measurement was calibrated by the digital skull phantom combined with the geometric model of the detector. The retention of 241Am in the worker’s skull was calculated. Results The proportion of skull dry weight relative to the whole-body bone dry weight was used as the coefficient to calculate the 241Am deposition in the whole-body bone from the measured activity of skull 241Am. Conclusion With the retention of 241Am in the skull and the proportion of skull dry weight, the retention of 241Am in the whole-body bone of the worker was calculated to be about 806 Bq.

Measurement of thyroid 131I activity in 162 iodine treatment workers in Hubei Province, China / 中国辐射卫生

Objective To determine the current status of occupational internal exposure to 131I in the thyroid of nuclear medicine workers, to explore the influencing factors for internal exposure, and to provide a basis for the radiation safety management of nuclear medicine. Methods The cluster sampling method was used to select 162 workers practicing 131I treatment in 24 hospitals in Hubei Province, China. Thyroid 131I activity levels were measured in vitro using a portable γ-spectrometer, and the committed effective dose was estimated. Results The thyroid 131I activity detected in 13 (54.17%) hospitals was above the lower limit of detection of the instrument. Two hospitals had the highest detection rates, 62.50% and 61.90%; the difference was significant compared with the remaining 11 hospitals (P < 0.0001). Thyroid 131I was detected in 34 workers in total, with a detection rate of 20.99% and a mean activity of 179.09 ± 138.71 (6.02-589.74) Bq. The highest detection rates were found in cleaners and nurses, which were 35.71% and 33.33%, respectively, with no significant difference in detection rate between positions (least P > 0.08). The mean value of the committed effective dose was 0.68 ± 0.52 (0.02-2.22) mSv/a in the 34 workers. Conclusion The 131I consumption and workplace ventilation may be important factors affecting the level of internal exposure. It is important to strengthen the training of nuclear medicine workers on radioprotection and workflow management, as well as the regular monitoring of occupational internal exposure for 131I treatment-related workers.

Internal exposure levels of thyroid 131I in nuclear medical staff / 环境与职业医学

Background Based on numerous epidemiological studies, radionuclide 131I can result in thyroid disease. Objective To study the contamination level of thyroid 131I in 131I treatment associated radiation workers in nuclear medicine departments in Shanghai. Methods Based on a general survey on basic situation of nuclear medicine in Shanghai, the level of internal exposure of radiation workers involved in 131I treatment was assessed with questionnaires and on-site monitoring. A portable γ spectrometer was used for on-site detection, the intake and annual effective dose were estimated according to the measurement results. Physical examination reports were collected for radionuclide positive workers, and chromosome testing was performed. Results There were 579 nuclear medicine workers and 175 were engaged in 131I treatment in Shanghai. 131I was detected in thyroid of 18 workers, with a detection rate of 10.3%. Among them, the detection rates of thyroid 131I in nurses and cleaners were 23% and 25% respectively. The mean measured activity of thyroid 131I was 306.1 Bq and the maximum measured activity was 3716.9 Bq (nurse). The maximum intake was estimated at 37544 Bq and the median was 786.4 Bq. The average annual committed effective dose was 1.22 mSv and the maximum value was 14.87mSv. The chromosomal aberration rates of all detected workers were negative, and all blood indicators were normal except one with low hemoglobin. Conclusion The annual dose of nuclear medical staff engaged in 131I treatment does not exceed the national standard limit, but the internal exposure of nurses and cleaners should not be ignored. On the basis of strengthening protection and decontamination, routine internal exposure monitoring should be carried out.

Measurement and evaluation of thyroid 131I activity in iodine treatment workers / 中华放射医学与防护杂志

Objective:To understand the 131I activity in thyroid of therapy workers in nuclear medicine department, and estimate the annual committed effective dose, in order to analyze the internal exposure of them. Methods:Six hospitals were investigated and 131I activity of thyroid was measured. The detection rate and activity value of thyroid 131I activity of therapy workers in nuclear medicine department were obtained from the six hospitals, and then the intake and annual committed effective dose were calculated. Results:A total of 63 iodine therapy workers from six hospitals were measured and 131I was detected for 52 workers among them, with the detection rate of 83% and 131I activities mostly lower than 200 Bq. The estimated annual committed effective dose ranged from 0.23 to 7.78 mSv. The annual committed effective dose to 84.6% of the workers was less than 2 mSv. Conclusions:Iodine therapy workers in nuclear medicine department should receive routine internal exposure personal monitoring, and the radiation protection system in all hospitals needs to be further improved.

Direct measurement of urine tritium and estimation of internal doses to personnel at pressurized heavy water reactor nuclear power plants / 中华放射医学与防护杂志

Objective:To explore the optimization of tritium internal exposure monitoring and dose estimation for radiation workers at pressurized heavy water reactor nuclear power plants (PHWR NPPs).Methods:A total of 92 radiation workers at Candu-6 PHWR NPPs were observed to calculate the distribution of quenching index (tSIE). Ten samples with tSIE values ranging from 160 to 460 were selected to make the blank urine quenching curve. By comparing with the quenching curve accompined with the equipment, the optimization of correlationship of urine tritium measurement system was carried out. In estimating tritium internal radiation dose, the dose coefficient was optimized and adjusted by comparing the Canadian algorithm with the national standard algorithm. Dead time correction curve was drawn by means of heavy water simulation experiment diluting main heat transfer system.Results:Through the analysis and optimization of tritium internal dose estimation, the optimal dose coefficient was determined to be 4.8 and the quenching curve of blank urine sample was made. By comparison, it was found that the deviation was larger when tSIE<200, which confirmed the necessity of blank curve. When the tritium concentration in urine was higher than 2.4×10 4 Bq/ml, the urine sample needed to be diluted and then measured to correct the effect of death time. Conclusions:By optimizing both tritium internal exposure monitoring and dose estimation, not only the collective dose management can be improved, but also the unplanned tritium intake can be detected and treated in time, which plays an important role in ensuring the protection and safety of the radiation workers at PHWR NPPs.

Measurement of 131I activity in thyroid of workers at the place of radioiodine therapy in six hospitals / 中华放射医学与防护杂志

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.

Investigation of two types of portable γ spectrometer applicability for measurement of thyroid 131I activity and internal doses to radiation workers / 中华放射医学与防护杂志

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.

Preliminary study on assessment of internal dose to workers exposed to 131I radionuclide / 中华放射医学与防护杂志

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.

Ongoing research on monitoring of internal exposure of nuclear medical staff / 中华放射医学与防护杂志

With the wide application of nuclear medicine and the increase in the number of related staff, the potential occupational health problems should receive enough attention. At present, the personal dose monitoring of most radiation workers in nuclear medicine is mainly based on the information on external exposure provided by thermoluminescence dosimeters whereas the routine internal exposure monitoring has not fully been carried out, thus resulting in underestimating their annual effective dose. Comprehensive personal dose monitoring is not only an important part of occupational health monitoring, but also a crucial means of occupational health management. In this paper, the characteristics of internal exposure in nuclear medicine were analyzed, the monitoring techniques and dose estimating method were introduced, and several commonly used softwares were listed, so as to comprehensively and objectively learn about the current internal radiation exposure of nuclear medicine workers, and to provide reference for health administration departments to formulate regulatory policies and protection requirements.

Analytical method for 14C in urine / 中华放射医学与防护杂志

Objective:To improve the analytical method of radionuclide 14C, and estimate the internal dose caused by 14C to human, in order to protect the health of workers and the public in workplaces involving potential 14C exposure. Methods:Urine samples were pretreated by wet oxidation. In the analysis, potassium persulfate was used as an oxidant to decompose urea into carbon dioxide, which was absorbed by 1 mol/L sodium hydroxide, and the absorption solution was converted into calcium carbonate precipitation. After calcium carbonate powder was prepared into sample source by suspension method, the low background liquid scintillation counter was applied to measure the radioactivity, which can be used for calculating the result.Results:The reaction time optimized by using carbamide as carrier was 1 h. For 80 ml urine, the amount of potassium persulfate used was 10 g. The method recovery rate reached about 100%. Four real urine samples were tested using the optimized method, and the result of activity concentration 14C was 0.32, 0.60, 0.86 and 0.74 Bq/L, respectively. Conclusions:The optimized method had good stability, high accuracy and stable experimental result, which could meet the needs of routine radiological detection. The establishment of a quantitative method for 14C in urine sample has improved the methodological system for 14C monitoring.

Estimation of internal dose with aerosol clust inhaled by non-uranium miners / 中华放射医学与防护杂志

Objective To establish a method for estimating internal dose from aerosol inhalation in non-uranium miners.Methods Aerosol samples in a tunnel in Dongchuan Copper Mine in Yunnan Province were collected by portable high flux air sampler.Radionuclides collected at the sampler filters were analyzed by the gamma spectrometry.Annual committed effective dose due to inhalation of the aerosol dust was estimated using the formula provided by ASTM.Results Radionuclides collected in two aerosol samples were anlayzed,the annual committed effective doses due to inhalation of 1 μm and 5 μm aerosol were estimated.Conclusions The method of using high flux air sampling and gamma spectrometry is explored to estimate the dose from aerosol inhalation.

Progress on Adverse Effects of Indoor Radon / 环境与健康杂志

The environmental sources of radon, its properties, pathways of human exposure, mechanisms of tox-icity and adverse health effects are described. This paper presents a review of research progress on radon in the recent ten years, which includes pollution levels in indoor air, internal exposure dose of human beings, remedial measures for decreasing the hazards induced by radon and main technical methods to reduce radon concentration in indoor air. Some reference data suggests that with the economic development and the improvement of residential environment, the air conditioners and unqualified building materials or decoration materials being used more extensively in residences. As a result, indoor air radon pollution and its impact on health are becoming of wide concern.