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Radiation-induced GATA3 expression in lung epithelial cells and mechanism of RNA methylation

Junxuan YI ; Xiaodan DONG ; Wenxiang XUE ; Shuying GAO ; Naiwen XUE ; Shunzi JIN

Chinese Journal of Radiological Health.2023;32(3):223-229. doi:10.13491/j.issn.1004-714X.2023.03.001

Objective: To investigate GATA3 expression and the regulatory mechanism of m6A modification in the re- sponse of alveolar epithelial cells to radiation, and to provide a new therapeutic target for radiation-induced lung injury based on its pathogenesis. Methods: Human lung epithelial cell line (A549) and mouse lung epithelial cell line (MLE-12) were exposed to X-ray irradiation with a single dose of 10 Gy (dose rate 1 Gy/min) and 6 Gy (dose rate 0.75 Gy/min), respect- ively. The expression of VIRMA gene (RNA methylase) was inhibited by lipofection of A549 cells and MLE-12 cells with shRNA-VIRMA plasmid and siRNA-VIRMA interfering fragment, respectively. Quantification of m6A RNA methylation was performed by colorimetry. Changes in the expression of mRNAs of VIRMA, GATA3, and epithelial-mesenchymal transition (EMT) markers in irradiated A549 and MLE-12 cells were determined by qRT-PCR. Changes in the expression of VIRMA, GATA3, and EMT marker proteins in irradiated A549 and MLE-12 cells were determined by Western blot. Results: Radiation up-regulated the expression of methylase VIRMA in A549 and MLE-12 cells, which in turn enhanced the m6A of total RNA and the expression of GATA3 gene and protein, resulting in EMT. Furthermore, in A549 and MLE-12 cells, interference of the VIRMA gene significantly reduced the expression of GATA3 gene and protein and the expression of EMT-related molecules. Conclusion　 Radiation induces m6A modification in alveolar epithelial cells, which up-regu- lates the expression of GATA3 gene and induces EMT, thus playing an important role in the process of radiation-induced lung injury.

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Preliminary experimental analysis of the feasibility of quartz glass for radiotherapy dosimetry

Xiangjie MA ; Zhijian HE ; Jilong YUAN ; Qinghuan JIANG ; Mingsheng LI ; Xiao WEI ; Yuze YANG ; Jinsheng CHENG

Chinese Journal of Radiological Health.2023;32(3):230-234. doi:10.13491/j.issn.1004-714X.2023.03.002

Objective To explore the feasibility of quartz glass for radiotherapy dosimetry through the experimental study of the thermoluminescence characteristics of synthetic quartz glass. Methods The thermoluminescence glow curves of quartz glass under different annealing conditions were analyzed, the thermoluminescence characteristics of quartz glass were studied, and the measurement parameters were optimized. Using the Co-60 reference radiation field in the National Secondary Standard Dosimetry Laboratory, the quartz glass samples under different annealing conditions were irradiated following the dose levels of radiotherapy, i.e., 0.5, 1.0, 2.0, 4.0, 6.0, 8.0, and 10.0 Gy, respectively. According to the relationship between the absorbed dose of quartz glass and the relative thermoluminescence signal intensity, the linearity and dispersion of the dose response of quartz glass were obtained, and the feasibility of quartz glass for radiotherapy dosimetry was analyzed. Results The linear correlation coefficient of dose response of quartz glass under annealing condition of 430℃ for 10 min was 0.9984, and the dose response dispersion was 0.97% at the absorbed dose of 2 Gy. The linear correlation coefficient of dose response of quartz glass under annealing condition of 600℃ for 1 h was 0.9911, and the dose response dispersion was 1.4% at the absorbed dose of 2 Gy. Conclusion Preliminary results suggest that quartz glass with annealing condition of 430℃ for 10 min has the potential to be used for radiotherapy dosimetry.

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Analysis of results of national personal dose monitoring ability assessment in 2016—2021

Jie LIU ; Jingzhi SUN ; Jiawu FENG ; Xuan ZHOU ; Li ZHANG ; Meng BI

Chinese Journal of Radiological Health.2023;32(3):235-239. doi:10.13491/j.issn.1004-714X.2023.03.003

Objective To analyze the results of national personal dose monitoring intercomparison and assessment of Hubei Provincial Hospital for Occupational Disease in 2016—2021, to investigate the influencing factors for monitoring results, and to improve the ability of personal dose monitoring. Methods The assessment was completed according to the requirements of The National Comparison Scheme for Individual Dose Monitoring Ability and Testing Criteria of Personnel Dosimetry Performance for External Exposure (GBZ 207—2016). Results The assessment results were qualified in 2016—2017 and 2020 and excellent in 2018—2019 and 2021. Conclusion The ability of personal dose monitoring in our laboratory has been continuously improved. The monitoring results are accurate and the data processing is standardized, which meet the requirements of relevant standards for personal external exposure dose monitoring.

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Dose estimation in etiology of occupational radiogenic neoplasms: A case analysis

Jing WANG ; Yingping GAO ; Dan MEI ; Kui MA ; Liangying MEI ; Xiaoguang FANG

Chinese Journal of Radiological Health.2023;32(3):240-244. doi:10.13491/j.issn.1004-714X.2023.03.004

Objective To analyze the problems and solutions in the diagnosis of a patient with occupational radiogenic neoplasms. Methods The dose conversion method was selected in dose estimation. Personal dose equivalent, skin absorbed dose, and reported detection data were converted into red bone marrow absorbed dose. The upper 95% confidence limit of the probability of causation (PC 95%) was calculated. Results The PC 95% of cancer due to radiation in the worker was 66.38%, which suggested occupational radiogenic neoplasms. Personal dose data were missing in dose estimation. The current dose estimation standard lacked bedside radiography and CT operation type, and the dose conversion formula was not perfect. Conclusion In the judgment of occupational radiogenic neoplasms, the estimated dose showed uncertainty. There is an urgent need to formulate and promulgate dose estimation standards that are operational and in line with the current development of radiological diagnosis and treatment technology and equipment.

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Comparison of methods for determination of gross α and gross β radioactivity in soil

Qiang XIONG ; Xiao GE ; Linlin YAN ; Fei CHEN ; Zhen ZHANG

Chinese Journal of Radiological Health.2023;32(3):245-249. doi:10.13491/j.issn.1004-714X.2023.03.005

Objective To improve the determination of gross α and gross β radioactivity in soil, establish a fast and accurate method for soil radioactivity analysis, and provide a basis for establishing standard methods for analysis of gross α and gross β radioactivity in soil. Methods Using the method of soil nuclide extraction and the sample preparation method for low background α/β counter, an extraction-enrichment method was established to monitor the radioactivity of gross α and gross β in soil. Meanwhile, the radioactivity of gross α and gross β in the same soil samples was determined using the direct paving method. An optimal method of monitoring gross α and gross β radioactivity in soil was put forward by comparing the advantages and disadvantages of the two methods. Results With the direct paving method, the radioactivity of gross α and gross β in soil was 0.47 Bq/g and 0.85 Bq/g, respectively; and the minimum detection limit was 0.04 Bq/g and 0.02 Bq/g, respectively. With the extraction-enrichment method, the radioactivity of gross α and gross β in soil was 0.32 Bq/g and 0.29 Bq/g, and the minimum detection limit was 0.02 Bq/g and 0.01 Bq/g. Conclusion Comparison of the two detection methods showed that the direct paving method is more accurate and easier to operate, while the extraction-enrichment method is complex in operation and has relatively large system error but provides a lower minimum detection limit.

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Response of radioactivity meter in vertical direction of ionization chamber

Ying SONG ; Hui LIU

Chinese Journal of Radiological Health.2023;32(3):250-253. doi:10.13491/j.issn.1004-714X.2023.03.006

Objective To determine the responses of radioactivity meter at different positions in the vertical direction of the ionization chamber by measuring different radioactive sources. Methods The radiation of cesium-137, cobalt-60, and americium-241 nuclides was measured at different positions in the vertical direction of the ionization chamber with commonly used clinical radioactivity meters. The measured values were fitted to obtain three trend lines. The maximum deviation of the measured values was estimated according to the trend line, and the deviation was estimated at different syringe needle heights. Results According to the trend lines, the maximum deviation of the radioactivity meter CRC-55tR in measuring cesium-137, cobalt-60, and americium-241 nuclides was 5.15%, 5.98%, and 6.25% respectively. The radioactivity meter RM-905a was used to measure three nuclides at different syringe needle heights, and the maximum deviations were −4.33%, −9.9%, and −12.65%, respectively. Conclusion The three nuclides showed different change patterns in measurement with CRC-55tR and RM-905a but similar change patterns in measurement with the same radioactivity meter. The values measured with the same radioactivity meter showed significant deviations at different positions in the vertical direction of the ionization chamber. It is recommended to make position correction for commonly used nuclides. Reducing measurement error and improving measurement accuracy of nuclides are of great significance for radiation protection.

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The radioactivity levels of food and the dose in residents due to food intake around Shidaowan Nuclear Power Plant

Wei ZHANG ; Chundong XIA ; Xianpeng ZHANG ; Yi LIU ; Xinyun WANG

Chinese Journal of Radiological Health.2023;32(3):254-258. doi:10.13491/j.issn.1004-714X.2023.03.007

Objective To analyze the radionuclide levels in food and the committed effective dose due to food intake in residents around the Shidaowan Nuclear Power Plant (SNPP). Methods Daily food samples were collected within 30 km radius around the nuclear power plant in 2019—2022. The radioactivity levels before and after the operation of SNPP were determined. The data were combined with the dietary consumption of residents in Shandong province, China to estimate the committed effective dose. Results The radionuclides ²³⁸U, ²³²Th, ²²⁶Ra, and ⁴⁰K in food were at normal background levels, and the average radioactivity was (0.062 ± 0.004), (0.121 ± 0.007), (0.162 ± 0.010), and (92.4 ± 5.5) Bq/kg fresh weight. Trace ¹³⁷Cs and ⁹⁰Sr were detected in some food samples and the average radioactivity was (0.047 ± 0.003) and (0.193 ± 0.200) Bq/kg fresh weight. The levels of radionuclides did not increase after the operation of SNPP compared with that before operation. The estimated committed effective dose in residents due to food intake was 0.205 mSv. Conclusion The radioactivity of food in the area around SNPP shows no difference before and after operation, and the dose burden is low in local residents.

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Development of a simplified phantom for calibration of whole-body counter

Jianhua WU ; Hongchao PANG ; Zhiping LUO ; Yang LIU ; Xinglong LI ; Guojun YUAN

Chinese Journal of Radiological Health.2023;32(3):259-263. doi:10.13491/j.issn.1004-714X.2023.03.008

Objective To develop a simplified phantom for the calibration of whole-body counters. Methods A simplified phantom design method for the calibration of whole-body counters was established based on the process and method of calibrating whole-body counters. By using the established method and Monte Carlo method, a simplified phantom including the total body, thyroid, lungs, and gastrointestinal tract was designed to calibrate the ORTEC-Stand FAST II whole-body counter. The simplified phantom was compared with the BOMAB phantom through experimental measurements. Results Within the range of 50 keV to 2 MeV, for rays of the same energy in the same organ of the simplified phantom and BOMAB phantom, the simulated data of detection efficiency by whole-body counting showed an error within 5%, and the experimental measurements showed an error within 10%. Conclusion We developed a simplified phantom for the calibration of the whole-body counter, demonstrating the feasibility of using the simplified phantom instead of a physical body phantom for whole-body counter calibration, which can greatly facilitate whole-body counter calibration for internal radiation monitoring.

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Measurement of thyroid ¹³¹I activity in 162 iodine treatment workers in Hubei Province, China

Gangtao SUN ; Fang WANG ; Jianfeng ZHANG ; Xiaoliang LI ; Hezheng ZHAI ; Wenshan ZHOU

Chinese Journal of Radiological Health.2023;32(3):264-269. doi:10.13491/j.issn.1004-714X.2023.03.009

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.

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Assessment of americium retention in bone by measuring ²⁴¹Am in the skull with a whole-body counter

Mengmeng WU ; Wei WANG ; Xiaodun LI ; Ling CHEN

Chinese Journal of Radiological Health.2023;32(3):270-275. doi:10.13491/j.issn.1004-714X.2023.03.010

Objective To assess the retention of²⁴¹Am in the whole-body bone of worker by measuring the retention of²⁴¹Am 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.

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