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  • Commentary
    Assessment of Prospective Cancer Risks from Occupational Exposure to Ionizing Radiation—Introduction to IAEA TECDOC 1985
    XUE Xian, SU Yinping, ZHANG Pinhua, SUN Quanfu
    2022, 31(5): 531-534. https://doi.org/10.13491/j.issn.1004-714X.2022.05.001
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    As part of the human environment, ionizing radiation can produce adverse tissue reactions known as deterministic effects at sufficiently high exposure levels, and cause stochastic effects (cancer and genetic diseases), where single cells with mutations can trigger somatic or genetic effects, even at low exposure levels. Given the unfavorable health effects of radiation, a comprehensive technical report is warranted to address the measurement and control of radiation exposure levels. The Assessment of Prospective Cancer Risks from Occupational Exposure to Ionizing Radiation published by the International Atomic Energy Agency fills this gap. This paper outlines the methodology of prospective cancer risk assessment for workers occupationally exposed to radiation, which provides a flexible framework based on radiobiology, risk modeling, and epidemiological data and a new tool for managing occupational radiation exposure and assessing potential risks from occupational radiation exposure.
    • Original Articles
  • Original Articles
    Role of complement in radiation-induced lung injury
    GENG Shuang, LI Qian, XI Tingting, WANG Meiyu, GUO Haoxin, WANG Zhixin, BI Xiaoguang, YAN Chengming, YANG Zhihua, WANG Yilong, ZHU Maoxiang
    2022, 31(5): 535-541. https://doi.org/10.13491/j.issn.1004-714X.2022.05.002
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    Objective To investigate the role of complement in radiation-induced lung injury in mice after chest irradiation with 60Co γ-rays at a single dose of 20 Gy.Methods C57BL/6 mice underwent chest irradiation with 60Co γ-rays at a single dose of 20 Gy, followed by observation for the inflammatory reaction of the lung tissue in the early stage (within 15 d) and pulmonary fibrosis in the later stage (30 and 180 d). Enzyme-linked immunosorbent assay was used to measure the levels of C2, C3a, C4, and C5b-9 in the lung tissues at 1, 3, 7, 15, 30, and 180 d after irradiation. The expression of complement mRNA in BEAS-2B cells after irradiation was determined using RT-PCR.Results Radiation-induced lung injury in micepresented as inflammatory response in the early stage and fibrosis in the late stage. Complement C2, C4, and C5b-9 complexes were increased in the early period (3 or 7 d) after irradiation (P < 0.05), which might be associated with the inflammatory response induced by irradiation. During 3 to 180 d, complement C3a was significantly higher in the irradiated mice than in the control mice, suggesting a close relationship between C3a and radiation-induced lung injury. The irradiated cells showed increased mRNA expression of C2 and C3, with no changes in the mRNA levels of C4 and C5. Conclusion Different complement proteins have varying responses to radiation-induced lung injury, among which C3a is closely related to radiation-induced lung injury, suggesting that regulating C3a and its receptors may be a new way to prevent and treat radiation-induced lung injury.
  • Original Articles
    Exploration of 241Am measurement in fecal samples
    SONG Weina, YIN Yunyun, LI Aiyun, WANG Chuangao, LUO Zhiping, PANG Hongchao
    2022, 31(5): 542-547. https://doi.org/10.13491/j.issn.1004-714X.2022.05.003
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    Objective To preliminarily study and establish a method for measurement of the transuranic nuclide 241Am in fecal samples, and to provide technical support for internal radiation monitoring of staff.Methods Fecal samples were collected with a self-made stool sampler and treated with a self-made carbonization and ashing furnace. DGA resin was used to separate and purify 241Am from fecal samples. With 243Am as the tracer, the orthogonal method was used for condition optimization. Results The optimum conditions for separation and purification were: the acidity of HNO3 added into the column, 6 mol/L; column flow rate, 0.6 mL/min; and the volume of analytical solution,12 mL. The method based on inductively coupled plasma mass spectrometry showed a detection limit of 9.79×10-4 Bq for 241Am in fecal samples, which was satisfactory and feasible. Conclusion This method fills the vacancy of 241Am measurement in fecal samples to some extent, which is of practical significance for internal radiation monitoring and protection for analysts.
  • Original Articles
    Discussion on dose estimation methods for internal exposure to tritiumm
    GAO Pin, YANG Baolu, ZHOU Qiang, TUO Fei
    2022, 31(5): 548-552. https://doi.org/10.13491/j.issn.1004-714X.2022.05.004
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    Objective To discuss the selection of dose estimation methods for internal exposure to tritium, their applicable working scenarios, and accurate dose estimation.Methods 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.Results 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 E(τ)1 values were higher than E(τ)3 values was 29.6%, and that of E(τ)2 higher than E(τ)3 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.Conclusion 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..
  • Original Articles
    Quality control analysis of test items based on Philips Digital Diagnost DR
    ZHAO Zhixin, SUN Gangtao, ZHAI Zipo, WANG Qiang, WANG Haihua, ZHU Bo, QIAN Qian, YANG Yong, ZHAI Hezheng
    2022, 31(5): 553-557. https://doi.org/10.13491/j.issn.1004-714X.2022.05.005
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    Objective To explore the quality control results of Digital Diagnost digital radiography (DR), and also to analyze the differences in signal transfer characteristics (STP) of DR from different manufacturers, in order to provide a reference for quality control of testers and daily supervision of administrative staff. Methods According to WS 76—2020 “Specification for testing of quality control in medical X-ray diagnostic equipment”, the test items such as automatic exposure control (AEC) repeatability, AEC response, detector dose indication (DDI), STP, high-contrast resolution, and low-contrast resolution of Digital Diagnost DR were qualitatively controlled, and several common DRs on the market were selected to analyze their STP functional relationships. Results The baseline values of DDI, high-contrast resolution, and low-contrast resolution of Digital Diagnost DR were 19733, 2.8 Lp/mm, and H5 of image central pixel value, respectively; the quality control results of other test items met the requirements of WS 76—2020. The STP functional relationships of common DRs were mainly linear and logarithmic, but different models of DR from the same manufacturer might also have different STP functional relationships. Conclusion When testing some special test items of DR, attention should be paid to the influence of a variety of factors, while refining the test steps and condition settings for the test items. The simulation should be performed in accordance with the functional relationship provided by the manufacturer when analyzing the STP.
  • Original Articles
    Basic information on radiological health technical service institutions in Shaanxi Province, China
    JI Zhigang, LI Tianlai, XU Yi, YU Huilian, ZHAO Xianfeng, WANG Yao, WANG Wubin, TIAN Yanpeng
    2022, 31(5): 558-563. https://doi.org/10.13491/j.issn.1004-714X.2022.05.006
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    Objective To understand the basic information on radiological health technical service institutions in Shaanxi Province, China and analyze the main problems, and to strengthen the capacity building of radiological health technical service institutions in Shaanxi Province. Methods The radiological health technical service institutions registered in Shaanxi Province were investigated and analyzed by means of a questionnaire and literature review. Results There were 20 radiological health technical service institutions in Shaanxi Province, including 7 state-owned ones and 13 privately owned ones; of all the institutions, there were 3 disease control institutions, and 15 institutions obtaining the qualification of radiation protection evaluation, radiation health protection testing, and individual dose monitoring at the same time. The total number of radiation workers in the institution was 237, including 48.5% aged less than 35, 68.8% with bachelor degree or above, 54.4% with intermediate professional title or above, 26.5% with a major related to radiation protection, and 79.3% with national and provincial training. The institutions were equipped with 309 testing instruments, of which the radiation diagnostic performance testing equipment accounted for the largest proportion (52.4%). Conclusion The service scope and capacity of radiological health technical service institutions in Shaanxi Province can meet the current needs of the province, but the institutions need to be improved in terms of personnel, equipment, and service quality. The quality control of institutions needs to be strengthened to standardize the service behavior in the whole province.
  • Original Articles
    Comparison results of image analysis software for quality control of SPECT equipment
    TAN Zhan, LIU Hui, SONG Ying, MA Rui, TAN Guangxiang, HUANG Weixu
    2022, 31(5): 564-567. https://doi.org/10.13491/j.issn.1004-714X.2022.05.007
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    Objective To investigate the differences in output results between difference analysis software, and to provide a reference for the improvement of quality control and the standard revision of SPECT equipment. Methods The image analysis software for quality control held by 14 radiological health technical service institutions was selected as the research subjects using the cluster sampling method. The results of the comparison were analyzed and evaluated according to the Z-score method with certified reference values. Results In the comparison items of “intrinsic uniformity” and “intrinsic spatial linearity”, the number of software with suspicious, deviated and incorrect results accounted for a relatively high proportion, while the results of other comparison items were satisfactory. Conclusion The applicability of SPECT image analysis software lacks effective supervision measures. Relevant departments should introduce feasible measures to standardize the software production and update process, accelerate the construction of radiological health information reporting platform, and promote the healthy development of the radiation health testing industry.
  • Original Articles
    Results of the nationwide assessment of radionuclide γ spectrum measurement in 2018—2020
    DONG Qian, LOU Hailin, SUN Xiaoyu, LU Ying, TU Xingming, WANG Shaolin, ZHANG Zhuangzhuang
    2022, 31(5): 568-572. https://doi.org/10.13491/j.issn.1004-714X.2022.05.008
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    Objective To ensure the effectiveness and improve the capacity of laboratories in the measurement of γ spectra of radionuclides.Methods A statistical analysis was performed using relative deviation, accuracy, precision, and relative combined uncertainty for the nationwide assessment of radionuclide γ spectrum measurement.Results In the assessment from 2018 to 2020, our laboratory showed qualified or above results, and the performance in 2019 was excellent. The maximum relative deviation of 11 measurements from 2018 to 2020 was 18.01%. The assessment showed |Ztest|≤1 and Utest≤2.58 in 2018, |Ztest|≤1 and Utest≤1 in 2019, and Utest≤1 and Urel≤20% in 2020.Conclusion Our laboratory employs the correct method for radionuclide γ spectrum measurement, and the analysis data are accurate and reliable.
  • Original Articles
    Impact of COVID-19 on chest CT scan frequency in a general hospital
    LIU Fang, WANG Xiaoshan, SONG Gang, LU Feng, SU Jing, LIU Qian, NIU Fei, LI Zhen, MIN Nan, YANG Shuhui, QIN Zhanxia
    2022, 31(5): 573-576. https://doi.org/10.13491/j.issn.1004-714X.2022.05.009
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    Objective To explore the effect of coronavirus disease 2019 (COVID-19) on the frequency of chest CT scan. Methods A retrospective study was conducted to extract information on the number of outpatient, emergency, and inpatient visits and patients who had chest CT imaging examination from January 1 to December 31, 2020 and in the same period in 2019 through the hospital’s medical data platform for analysis, and the chi-square test was used to analyze whether the difference in the proportion of patients who had chest CT imaging examination between 2019 and 2020 was statistically significant. Results The proportion of outpatients and emergency patients with chest CT examination was significantly higher in 2020 than in 2019 (2.48% vs 1.47%, χ2 = 581.7, P < 0.000). The proportion of inpatients who underwent chest CT examination was significantly higher in 2020 than in 2019 (35.47% vs 28.01%, χ2 = 182.0, P < 0.000). Conclusion Under the COVID-19 epidemic, the proportion of chest CT examination in this hospital in 2020 shows a significant upward trend compared with the same period in 2019, which will increase the collective dose due to medical exposure, and the hospital should pay attention to the determination of the legitimacy of chest CT scan.
  • Original Articles
    Discussion on shielding calculation method for proton therapy room
    ZHANG Deqin, PAN Yang, LAI Jichuan, CHEN Jiaojiao, LIU Lantao
    2022, 31(5): 577-582. https://doi.org/10.13491/j.issn.1004-714X.2022.05.010
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    Objective To discuss the shielding calculation method for proton therapy room, and to provide a scientific basis for shielding design of proton therapy room and improvement of existing national standards. Methods Using the calculation formula and key characteristic parameters from national standards and Chinese and foreign literature, combining with the FLUKA Monte Carlo method, empirical formula calculation and Monte Carlo simulation were conducted for the neutron ambient dose equivalent rates of the focuses outside the shielding of proton therapy room. The estimation results of the two methods were analyzed. Results Relative to the calculation results of the single exponential formula in the two directions of 0° and 50° in the beam loss point of divergence slit (0.13 and 12.4), the calculation results of the double exponential formula (0.40 and 17.9) were more consistent with the Monte Carlo simulation results (0.32 ±0.19 and 18.2 ±4.98). The Monte Carlo simulation results of copper target and nickel target were similar, suggesting that the key characteristic parameters of concrete shielding for copper target could be well applied to the calculation of nickel target, but the neutron ambient dose equivalent rates were underestimated when applied to tantalum target, with a difference of 5.7 times and 1.3 times in the two directions of 0° and 40°, respectively. Conclusion The dose rate estimates based on the calculation formula and key characteristic parameters from Chinese and foreign literature are consistent with FLUKA simulation results, and this method can be used in the shielding design of proton therapy room as a supplement and improvement to the existing national standards.
  • Original Articles
    Investigation of radiation protection status in non-medical radiation institutions in Fujian Province, China
    ZOU Tianlu, ZHENG Senxing, WAN Yanfei, WENG Zhenqian, GUO Jinrui, LIU Pan
    2022, 31(5): 583-586. https://doi.org/10.13491/j.issn.1004-714X.2022.05.011
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    Objective To investigate the number and categorical distribution of non-medical radiation institutions in Fujian Province, China, and to explore the current situation of radiation occupational hazards prevention and control and the occupational health management of radiation workers in employing units.Methods The industrial enterprises engaged in the application of nuclear technology in our province were investigated, and different types of employing units were selected to monitor the radioactivity level in the workplace.Results A total of 377 non-medical radiation institutions were reported in the province, with a total of 5221 radiation workers (except luggage detector units); 1246 radiation workers held radiation worker certificates, accounting for 23.87%; 5103 radiation workers carried out personal dose monitoring, accounting for 97.74%; 5061 radiation workers participated in radiation protection knowledge training, accounting for 96.94%; a total of 4895 (93.76%)radiation workers received physical examination.Conclusion Health supervision authorities in Fujian Province should strengthen the supervision of non-medical radiation institutions, further improve the level of occupational health management, and protect the health rights and interests of radiation workers to the maximum extent.
  • Original Articles
    An investigation of radiation dose to adult subjects in computed tomography scanning in Shanghai, China
    QIAN Aijun, GAO Linfeng, YAO Jie, WEN Xuexin, WANG Bin, XIAO Hong, JIANG Zhou
    2022, 31(5): 587-591. https://doi.org/10.13491/j.issn.1004-714X.2022.05.012
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    Objective To investigate dose parameters in computed tomography (CT) scanning of common body parts inall public medical institutions in Shanghai, China, and analyze the dose distribution of CT scanning among adult subjects in Shanghai, and to provide a basis for establishing the diagnostic reference levels of CT scanning in Shanghai.Methods We selected at least one medical institution with CT services each from all 16 districts of Shanghai. In each medical institution, a piece of CT equipment with qualified annual inspection was sampled to investigate the doses to subjects in head, chest, abdomen, and lumbar spine scanning. We collected the basic information of the subjects, CT scanning parameters, volumetric CT dose index (CTDIvol), and dose length product (DLP).Results The scanning data of 1475 subjects were obtained. The 75th percentiles of the CTDIvol of the head, chest, abdomen, and lumbar spine were 57 mGy, 11 mGy, 16 mGy, and 23 mGy, respectively. The 75th percentiles of the DLP were 862 mGy·cm, 361 mGy·cm, 593 mGy·cm, and 550 mGy·cm, respectively.Conclusion CTDIvol and DLP differed significantly at different body parts, and also differed greatly at the same body parts. The DLP of men was slightly higher than that of women.
  • Original Articles
    Analysis of performance test results of some medical linear accelerators in Hebei Province, China, 2019—2021
    LI Peng, ZHANG Yuanyuan, JIANG Lihong, LI Xiaopeng, WANG Youcheng, LIU Yong, ZHANG Yu, NIU Qingguo
    2022, 31(5): 592-596. https://doi.org/10.13491/j.issn.1004-714X.2022.05.013
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    Objective To investigate the current situation of quality control in medical linear accelerators in Hebei Province, China. Methods The main performance indices of some medical linear accelerators in Hebei Province, 2019—2021 were tested according to the current relevant effective standards GB 15213—2016 Medical Electron Accelerators-Functional Performance Characteristics and Test Methods and WS 674—2020 Specification for Testing of Quality Control in Medical Linear Accelerator. Results A total of 175 medical linear accelerators were tested from 2019 to 2021, and the annual pass rates were 72.4% in 2019, 75.9% in 2020, and 79.4% in 2021. The overall pass rate of initial inspection was 76.0%, and the pass rate of reinspection was 100.0%. The index with the lowest pass rate in the initial inspection was square X radiation field uniformity, followed by dose deviation and square X radiation field symmetry. Conclusion Medical institutions should strengthen quality control management, conduct regular testing of medical linear accelerators, and timely correct dose deviation, so as to ensure the treatment effect of patients.
  • Original Articles
    Effects of grid methods on precision and efficiency of specific absorbed fraction calculation in Monte Carlo simulation
    ZHANG Weiyuan, ZHUO Weihai, CHEN Bo, JI Huajun
    2022, 31(5): 597-600. https://doi.org/10.13491/j.issn.1004-714X.2022.05.014
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    Objective To compare the precision and efficiency of computing the specific absorbed fraction (SAF) of a reference human with two grid methods in MCNP6.0. Methods Based on the adult female reference voxel phantom provided by the International Commission on Radiological Protection, assuming the liver as the source organ emitting single-energy photons (0.5 MeV), the SAF of each target organ/tissue was calculated by using the mesh method and repeated structure lattice method with the F4, F6, and *F8 tally cards in MCNP6.0. We compared the methods by assessing the relative deviation of SAF and computing time for 27 organs/tissues. Results Compared with reported data, the absolute values of relative deviations of SAF values for all the organs/tissues were less than 5%, except for the eye lens and skin. By using the repeated structure lattice-based *F8 tally, the relative deviations of SAF values of the organs/tissues were all smallest, but with the longest computing time. The computing time of the mesh-based F4 tally was slightly longer than that of the repeated structure lattice-based F6 tally, which was shortest.Conclusion The *F8 tally simultaneously simulating primary and secondary particle transport showed the highest precision. The mesh tally requireda longer computing time than the lattice tally when using the same tally card.
  • Original Articles
    Experimental analysis of clinical applicability of individualized customized materials
    WANG Yun, GU Peihua, WANG Jiehua, GONG Jinlan, CHEN Li, MU Yanshu, ZHANG Xiaoxiao, GUAN Chang, WANG Lu
    2022, 31(5): 601-605. https://doi.org/10.13491/j.issn.1004-714X.2022.05.015
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    Objective To study the feasibility of clinical application of an individualized customized material. Methods Five batches of individualized customized materials were randomly selected, from which 10 cm×11 cm samples were intercepted for experimental analysis. Among them, 10 cm×10 cm materials were selected to perform dosimetric analysis and HU change analysis before and after irradiation with a radiotherapy dose for breast cancer of 50 Gy as the irradiation basis. The center Point 1 on the lower surface of the individualized material and the center Point 2 of the solid water volume were selected for dosimetric analysis before and after the sample is irradiated. After reaching a sufficient amount of irradiation, the 1 cm×10 cm materials intercepted in the center position and the remaining 1 cm×10 cm materials after the first sampling were sent to the material science laboratory for analysis of physical properties of density, viscosity, hardness, and tear strength. Results In the comparative analysis of HU values before and after exposure, after receiving 50 Gy dose irradiation, the difference rate of HU value was 5.252%, which was close to the expected 5% difference rate in clinical medicine. In the dosimetric analysis of Point 1 and Point 2, the dose in the irradiated samples was significantly higher than that in the unirradiated samples; the dose in Point 1 increased by 3.742%, and the dose in Point 2 increased by 2.039%. Before and after irradiation, except for the physical density which showed a significant difference, there was no significant difference in viscosity, hardness, and tear strength. Conclusion The individualized customized material can meet the requirements of routine clinical medicine.
  • Original Articles
    Experimental analysis of clinical applicability of homemade in homogeneous phantom
    CHEN Jingjing, CHEN Honglin, YU Dehong
    2022, 31(5): 606-610. https://doi.org/10.13491/j.issn.1004-714X.2022.05.016
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    Objective To conduct experimental analysis of clinical applicability of a homemade phantom which is equivalent to multiple tissue densities of human body.Methods Materials with densities close to bone, lung, cavity, and soft tissue were manufactured and combined to obtain a homemade in homogeneous phantom. The electron density of equivalent materials was compared with the organs. Ten lung cancer patients in our department were recruited for dose verification of intensity modulated radiation therapy in the homemade phantom and solid-water phantom. The two phantoms were compared for characteristics in dose verification, and the dosimetric differences of the homemade phantom between the calculated values on treatment planning systemand measured values were statistically analyzed by SPSS 21.0 software.Results In the dose verification, the gamma pass rates (3 mm/3%) were more than 90% using both the homemade phantom and solid-water phantom. The measured values in homemade phantom were larger than those in solid-water phantom, and the maximum deviation was 11.5%. The AD and RD values of gamma pass rate in dose verification showed no significant differences between the two phantoms (P > 0.05).Conclusion The homemade phantom meets the accuracy requirement of clinical application and can be used in dose verification of intensity modulated radiation therapy plan.
  • Original Articles
    Value of chromosomal microarray analysis for genetic evaluation of fetal ultrasound abnormality
    XIAO Linling, XU Jun, ZHANG Xiaohong, GUO Guilan, TAN Jufang, HE Li, ZHANG Shuang
    2022, 31(5): 611-614. https://doi.org/10.13491/j.issn.1004-714X.2022.05.017
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    Objective To evaluate the value of chromosomal microarray analysis (CMA) for genetic evaluation of fetal ultrasound abnormality. Methods A total of 180 pregnant women with fetal abnormality detected by prenatal ultrasound diagnosis in the first trimester during the period from January 2020 through May 2022 were enrolled as the study subjects. All prenatal fetal screening samples were subjected to G-band karyotyping and CMA. Results G-band karyotyping detected normal karyotypes in 168 samples (93.85%) and abnormal karyotypes in 11 samples (6.15%), and CMA detected 17 positive samples (9.44%) and 163 negative samples (90.56%). The seventeen positive samples included 11 pathogenic copy number variations (CNVs) and 6 variants of unknown significance (VOUS), and there were 11 CMA-positive results consistent with G-band karyotyping, and 6 additional pathogenic CNVs mainly included microdeletion and microduplication syndromes. The detection rates of pathogenic CNVs were 11.11%, 2.63%, 2.78%, 4.00%, 0, 0, 11.11% and 0 among the fetuses with abnormal structure of the cardiovascular system, the lymphatic system, the nervous system, the digestive system, the cranial and face system, the skeletal system, the urinary system, and other system (χ2 =8.188, P = 0.316). All eleven fetuses with pathogenic CNVs detected by CMA were all induced for abortion. Conclusion CMA improves the detection of genetic abnormality among fetuses with ultrasound abnormality in relative to G-band karyotyping, which is feasible for prenatal cytogenetic diagnosis among fetuses with ultrasound abnormality
  • Original Articles
    Effects of flattening filter on dosimetry in fractionated stereotactic radiotherapy for brain metastases
    ZHU Zhijian, ZHANG Xiaoye, ZHANG Yan, SHI Tingting, HONG Jun, HE Dongcheng, HAN Jihua
    2022, 31(5): 615-619. https://doi.org/10.13491/j.issn.1004-714X.2022.05.018
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    Objective To investigate the dosimetric differences between volumetric modulated arc therapy (VMAT) with a flattening filter (FF) and flattening filter-free (FFF) VMAT in fractionated stereotactic radiotherapy for brain metastases. Methods Seventeen patients with brain metastases were divided into FF-VMAT group (VMAT plans with the FF mode) and FFF-VMAT group (VMAT plans with the FFF mode). The two groups were compared in terms of target volume dose parameters (D98%, D2% and Dmean), the conformal index (CI), the gradient index (GI), the gradient, normal brain tissue dose parameters (V5Gy, V10Gy, V12Gy and Dmean), monitor units, and beam-on time. Results Compared with the FF-VMAT group, the FFF-VMAT group had significantly lower GI (3.33 ±0.37 vs 3.27 ±0.35, P = 0.001), a significantly lower gradient [(0.85 ±0.20) cm vs (0.84 ±0.19) cm, P = 0.002], a significantly shorter beam-on time [(177.05 ±62.68) s vs (142.71 ±34.59) s, P = 0.001], and significantly higher D2% [(65.69 ±2.15) Gy vs (66.99 ±2.03) Gy, P = 0.001] and Dmean [(58.77 ±1.60) Gy vs (59.95 ±1.43) Gy, P <0.001]. There were no significant differences in the CI, the D98% of the target volume, the V5Gy, V10Gy, V12Gy and Dmean of the normal brain tissue, and monitor units between FFF-VMAT and FF-VMAT. Conclusion FFF-VMAT can better protect the normal tissue around the target volume, reduce the beam-on time, and improve treatment efficiency.
  • Original Articles
    Awareness of ionizing radiation safety and protection knowledge among clinical healthcare professionals
    DING Hongmei, LI Yuan
    2022, 31(5): 620-625. https://doi.org/10.13491/j.issn.1004-714X.2022.05.019
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    Objective To investigate the awareness of ionizing radiation safety and protection knowledge among clinical healthcare professionals.Methods A cross-sectional study was performed among 270 nurses using a self-designed questionnaire. The questionnaire included participants’ socio-demographic features, and knowledge of radiation physics and biology, principle of radiation use, radiation protection, and guideline for safe use of ionizing radiation. The questionnaire results were analyzed using the descriptive epidemiological method.Results A total of 270 questionnaires were assigned, and 252 valid questionnaires were recovered, with an effective response rate of 93.33%. Among the 252 respondents, 99.21% were female, 80.16% at the age of 25 to < 55, 31.35% with work seniority of 20 years and longer, 66.67% with an education level of bachelor degree, and 75.00% with a history of receiving medical radiation knowledge training and education. The awareness rates of the following problems were all more than 90%: “knowing the protocols concerning radiation workers who are pregnant”, “trying best to promote agreed safety protocols concerning radiation dose and radiation usage in my daily work and actions”, “being aware of the radiation safety arrangements at my work”, “understanding the meaning of radiation safety culture”, “understanding the warning signs concerning radiation while working in the control area”, “knowing the meaning of warning signs regarding radiation safety”, “knowing how to report abnormal events in radiation use”, “knowing how to properly use personal radiation protection equipment”, “understanding the principle of dose limitation in radiation protection”, “knowing how ionizing radiation is produced”, “know how the harmful effects of medical radiation are caused”, and “knowing how to document all the essential information concerning the use of radiation”; however, the awareness rates of “knowing how to account for differences between adult and child/adolescent patients in radiological examinations” and “understanding the meaning of the inverse square law in radiation protection” were very low. Conclusion The overall awareness of ionizing radiation safety and protection knowledge remains unsatisfactory among clinical healthcare professionals. The training on ionizing radiation safety and protection knowledge requires to be improved, and the radiation protection skills are recommended to be increased.
  • Original Articles
    Effect of ionizing radiation on thyroid function among medical workers in department of cardiovascular medicine
    XU Hanli, LIU Dan
    2022, 31(5): 626-630. https://doi.org/10.13491/j.issn.1004-714X.2022.05.020
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    Objective To examine the possible effect of ionizing radiation on thyroid function among medical workers in the department of cardiovascular medicine.Methods Forty-six medical workers in the department of cardiovascular medicine with exposure to ionizing radiation were enrolled as the study subjects. Subjects’ demographic features were collected. Serum free triiodothyronine (fT3), free thyroxine (fT4), and thyroid-stimulating hormone (TSH) levels were measured using chemiluminescence assay, and the annual personal dose equivalent (Hp (10)) received in 2019 and the fiver-year cumulative Hp (10) from 2015 to 2019 were measured using a thermoluminescent personal dosimeter. The associations of altered thyroid functions with subjects’ age, sex, previous history of thyroid diseases, family history of thyroid diseases, working post, work seniority, and previous history of exposure to ionizing radiation were evaluated using an exact logistic regression model. Results The incidence of subclinical hypothyroidism (elevated serum TSH level without alteration in fT3 or fT4 level) was 6.5% among the study subjects. The Hp (10) was 0 to 4.5 mSv among the subjects in 2019, with a mean dose of (0.2 ±0.7) mSv and a median dose of 0 mSv, and the five-year cumulative Hp (10) from 2015 to 2019 was 0 to 11.6 mSv, with a mean dose of (0.8 ±2.3) mSv and a median dose of 0 mSv. The exact logistic regression analysis showed that the altered thyroid functions were not significantly associated with age, sex, previous history of thyroid diseases, family history of thyroid diseases, working post, work seniority, or previous history of exposure to ionizing radiation (all P > 0.05).Conclusion Long-term exposure to low-dose ionizing radiation may be associated with an increased risk of subclinical hypothyroidism among medical workers in the department of cardiovascular medicine.
    • Review Articles
  • Review Articles
    Research progress on new operational quantities and the effects in area dose monitoring
    HUANG Zhuo, OU Xiangming, WEI Kedao
    2022, 31(5): 631-634. https://doi.org/10.13491/j.issn.1004-714X.2022.05.021
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    Operational quantities, which are used to estimate protection quantities in the field of radiation protection, are important in area monitoring. The current operational quantities show certain limitations as the particle types and energy ranges are expanded. The International Commission on Radiation Units and Measurements Report 95 proposed a new system of operational quantities, where the definitions and phantoms of the operational quantities are consistent with the protection quantities, enabling better estimation of the protection quantities over wider ranges of particle types and energies. This paper focuses on the effects of the new recommended operational quantity system in area monitoring from the aspects of phantom application, conversion coefficient updating, and monitor design and calibration.
  • Review Articles
    Development and application of emergency management information systems for medical radiation
    CHENG Ying, WAN Longyun, WU Xing
    2022, 31(5): 635-638. https://doi.org/10.13491/j.issn.1004-714X.2022.05.022
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    High-energy radiation derived from X-ray, γ-ray, neutrons, and other radioisotopes has been widely used for disease diagnosis and treatmentin clinical practice. Notably, high-energy radiation has been proven to increase the cure rate, prolong the survival time, and improve the quality of life among patients with malignant tumors. However, radiation poses huge threats to human health and life. Establishment of effective emergency management information systems for medical radiation is therefore of great significance to evaluate the radiation safety, predict the leakage of radioactive materials, and propose effective responses. This review summarizes the development and application of currently main emergency management information systems for medical radiation, so as to provide a reference for the establishment of sensitive and effective hospital-based radiation emergency management information systems.
  • Review Articles
    Recent advances in health hazards of long-term exposure to microwave radiation
    WANG Chi, HE Jun, ZHANG Li
    2022, 31(5): 639-644. https://doi.org/10.13491/j.issn.1004-714X.2022.05.023
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    With the development of the global information technology, electromagnetic equipment such as communication devices and new weapons has been widely deployed. Long-term exposure to electromagnetic radiation causes health hazards to people. Microwave is the most widely used electromagnetic wave. The article reviews the health hazards of long-term exposure to microwave radiation, including damages to the nervous, cardiovascular, blood, reproductive, endocrine, and immune systems and tumorigenesis, and summarizes the possible mechanisms of hazards of long-term exposure to microwave radiation, aiming to provide a theoretical basis for the mechanism study and the research and development of protection technology.