放射卫生作为传统五大卫生之一,"十三五"期间,放射卫生各项工作都取得了长足的进步:拥有一支体系不断完善、能力不断增强且具有凝聚力的放射卫生队伍,放射卫生法律法规和标准体系进一步完善,连续十余年持续深入开展放射卫生监测和风险评估,持续加强核辐射突发事件卫生应急准备与响应,援疆援藏工作扎实、效果明显,积极投身新冠疫情防控工作."十四五"期间,将推进防电离辐射技术支撑机构建设,进一步完善放射卫生监测工作,加强全国放射卫生机构能力和队伍建设,继续推进放射卫生法规标准体系建设,扎实深入做好核辐射突发事件卫生应急与医学救援准备与响应,凝练21世纪第三个十年的放射卫生重要科学与关键技术问题,深入开展放射卫生科学技术研究,加强放射卫生学科青年英才培养,依托世界卫生组织辐射与健康合作中心框架,积极组织实施区域和国际合作.

Objective:To investigate the changes of connexin 43 (Cx43) in human umbilical vein endothelial cells (HUVEC) after X-ray irradiation and its influence on the stiffness of irradiated cells.Methods:Western blot was used to detect the expression of Cx43 in HUVEC cells at different time points (0, 6, 12, 24 and 48 h) after different doses of X-ray irradiation (0, 2.5, 5, 10 and 20 Gy), and the phosphorylation levels of three phosphorylation sites (Ser279/282, Ser368 and Tyr265) of Cx43 at different time points (3, 6, 24 and 48 h) after 0, 5 and 10 Gy irradiation. The distribution of Cx43 protein in the irradiated HUVEC cells was detected by immunofluorescence. The stiffness changes of cells were detected by atomic force microscopy (AFM) at the depths of 50, 100 and 200 nm.Results:The expression of Cx43 in HUVEC cells was reduced at 6, 12, 24 and 48 h after 10 Gy X-ray irradiation( t=3.262, 3.708, 3.686, 6.825, P<0.05)and this decrease had a dose dependent manner at 24 h after 2.5, 5, 10 and 20 Gy irradiation ( t=3.034, 10.720, 13.130, 13.650, P<0.05). At 24 h after 5, 10 and 20 Gy X-ray irradiation, the distribution of Cx43 in HUVEC cells was transported from intercellular gap junctions to nucleus and perinuclear region. At 24-48 h after irradiation, the phosphorylation level of Ser368 at Cx43 increased and in a dose dependent manner. At 24 h after irradiation, the stiffness of the irradiated cells decreased significantly under the conditions of 100 and 200 nm ( t=3.362, 5.122, P<0.05), and recovered with overexpression of Cx43 ( t=2.674, 4.398, P<0.05). Conclusions:X-ray irradiation leads to the phosphorylation of Ser368 at Cx43, which promotes the degradation and nucleus/perinuclear translocation of Cx43 and reduces the stiffness of HUVEC. Increasing the expression level of Cx43 is helpful to the stiffness recovery of irradiated vascular endothelial cells, suggesting that Cx43 may be a potential target for regulating radiation injury of vascular endothelial cells.

OBJECTIVE:Pyroptosis is an inflammatory form of programmed cell death. This phenomenon has been recently reported to play an important role in radiation-induced normal tissue injury. Connexin43 (Cx43) is a gap junction protein that regulates cell growth and apoptosis. In this study, we investigated the effect of Cx43 on X-ray-induced pyroptosis in the human umbilical vein endothelial cells (HUVECs).METHODS:HUVECs, Cx43 overexpression, and Cx43 knockdown strains were irradiated with 10 Gy. Proteins were detected using western blot analysis. Cell pyroptosis was evaluated using the fluorescence-labeled inhibitor of caspase assay (FLICA) and propidium iodide staining through flow cytometry and confocal microscopy. Cell morphology and cytotoxicity were detected by scanning electron microscopy and lactate dehydrogenase release assay, respectively.RESULTS:Irradiation with 10 Gy X-ray induced pyroptosis in the HUVECs and reduced Cx43 expression. The pyroptosis in the HUVECs was significantly attenuated by overexpression of Cx43 as it decreased the level of active caspase-1. However, interference of Cx43 expression with siRNA significantly promoted pyroptosis by increasing the active caspase-1 level. Pannexin1 (Panx1), a gap junction protein regulates pyroptosis, and its cleaved form is used to evaluate channel opening and active state. The level of cleaved Panx1 in the HUVECs and Cx43 knockdown strains increased in the presence of X-ray, but decreased in the Cx43 overexpression strains. Furthermore, interference of Panx1 with siRNA alleviated the upregulation of pyroptosis caused by Cx43 knockdown.CONCLUSION:Results suggest that single high-dose X-ray irradiation induces pyroptosis in the HUVECs. In addition, Cx43 regulates pyroptosis directly by activating caspase-1 or indirectly by cleaving Panx1.

222Rn concentrations in underground drinking water samples in 12 cities from seven provinces (municipalities), China were determined by using a continuous radon monitor with air-water exchanger. A total of 73 underground water samples were collected. The observed radon levels were in a range of 1.0-63.8 Bq l-1, with a mean of 11.8 Bq l-1. The annual effective dose from inhalation of water-borne radon for average radon content in underground water was 72.6 μSv and for maximal observed radon concentration in underground water the corresponding dose was 393.8 μSv. The dose contribution of inhalation dose from water-borne radon should be paid attention in some granitic area.

Objective To study the role of Cx43 in X-ray induced apoptosis of HUVEC cells and its mechanism.Methods Flow cytometry was used to detect the apoptosis of HUVEC cells at 48-96 h after 10 Gy X-ray irradiation and at 72 h after irradiation of different doses.Western blot was used to detect the protein expressions of Cx43 and cleaved caspase-3 in HUVEC cells at 72 h after 0,5,10 and 20 Gy irradiation.Small interfering RNA was transfected into HUVEC cells to silence Cx43 expression,the Cx43 bearing plasmid was transfected into cells to overexpress Cx43.The effect of Cx43 knockdown or overexpression on apoptosis induction and cleaved caspase-3 protein expression were detected by flow cytometry and Western blot,respectively.Results The apoptosis of HUVEC increased significantly from 48 h to 96 h after X-ray irradiation and in a dose-dependent manner at 72 h after irradiation.The expression of Cx43 protein was negatively correlated with the dose but the expression of cleaved caspase-3 was positively correlated with the dose in the range of 0-20 Gy.After Cx43 silencing,the proportion of early apoptosis and apoptosis combined with dead cells were significantly higher than that of the siRNA control group(t =3.674,6.375,P ＜ 0.05).After Cx43 overexpression,the proportion of early apoptosis and apoptosis combined with dead cells were significantly lower than that of vector control group(t =9.399,11.190,P ＜ 0.05).The expression of cleaved caspase-3 in the Cx43 silencing group was higher than that in the siRNA control group,but this protein in the Cx43 overexpressed group was lower than that in the vector control group.Conclusions Cx43 may protect X-ray irradiated HUVEC cells from apoptosis by down-regulating the activation of caspase-3.

Cell death and tissue injury occur as a result of radiation accidents and radiotherapy. The role of endothelial cell damage in mediating radiation-induced acute tissue injury has been extensively studied. We previously demonstrated that ferulic acid (FA) mitigates radiation-induced hematopoietic injury in mice and lessens radiation-induced oxidative damage in human umbilical vein endothelial cells (HUVECs). The purpose of the current study was to determine whether FA can protect HUVECs from radiation toxicity in a cell model via the thrombomodulin (Thbd) pathway, an anti-radiation pathway with anticoagulant, anti-inflammatory and antioxidant properties. HUVEC culture media was supplemented with FA 12 h before 4 Gy 60Co gamma irradiation. At 30 min postirradiation, the FA media was refreshed, then renewed once daily. HUVEC injury was assessed at day 5 postirradiation through cell proliferation analysis. Ferulic acid significantly ameliorated HUVEC radiation injury, as evidenced by increases in cell viability and angiogenesis and decreases in G2/M cell cycle arrest and levels of high mobility group box 1 protein (HMGB1), interleukin (IL)-6 and IL-8. These findings can be attributed to the effect of FA on the Thbd promoter, resulting in increased expression of Thbd and activated protein C with associated radioprotection. These observations indicate that FA intervention significantly ameliorates HUVEC radiation injury via the Thbd pathway. Therefore, FA could be further developed as a potential agent to mitigate radiation-induced damage.

目的:通过观察γ射线诱导小鼠胸腺淋巴细胞的微丝形态变化和对丝切蛋白(cofilin)磷酸化的影响,探讨cofilin及相关蛋白在辐射损伤中的作用.方法:将36只BALB/c小鼠按对照组(0 h),照射后3、6、9、12和24h时间点随机分为6组,每组6只,除对照组外,其余各组均给予2 Gyγ射线诱导,根据cofilin蛋白表达规律,确定取材时间.另将24只BALB/c小鼠按γ射线诱导剂量随机分为未照射(0Gy)组、2、6和10 Gy组共4组,照射3h后取材,观察淋巴细胞微丝形态,进行cofilin蛋白1(cofilin 1)、磷酸化cofilin蛋白(p-cofilin)、LIM激酶1(LIMK1)、TES激酶2(TESK2)和Slingshot家族的磷酸酶2(SSH2)表达检测.结果:BALB/c小鼠在2Gy γ射线照射3h后胸腺淋巴细胞co砌基因的mRNA和蛋白表达均显著下调(P＜0.05),因此后续实验选择照后3h为取材时间.通过对cofilin及相关蛋白表达的检测,发现随着γ射线照射剂量的增加,胸腺淋巴细胞cofilin的表达逐渐增加,与对照组相比,以10 Gy组增加最为明显(P＜0.05);而p-cofilin的表达则减少,10 Gy组减少最为明显(P＜0.05).LIMK1、TESK2和SSH2的表达在照射后无显著变化(P＞0.05).结论:随着照射剂量的增加,更多的SSH2使p-cofilin的Ser3位点去磷酸化,胞质内cofilin的量增多,参与到微丝骨架组装的过程中,细胞的迁移能力增强.

Objective To observe the effect and the mechanisms of ferulic acid on radiationinduced damage of mice peripheral blood and bone marrow hematopoietic function.Methods Ninety-six mice were randomly divided into sham irradiation group,irradiation group,positive drug group and 10,30,90 mg·kg-1 ·d-1 ferulic acid group,16 mice per group.Mice were exposed to 3.5 Gy γ-rays 24 h after first drug taken.Then,mice were given drugs for 7 d after irradiation.White blood cells in peripheral blood of 10 mice per group were counted 2 d before irradiation and 3,7,10,15 and 22 days after irradiation.The bone narrow of the other six mice was taken to detect the micronuclei frequency of polychromatic erythrocyte,the hematopoietic progenitor cell colony formation capacity,Thbd and HMGB1 protein expressions in mice bone marrow on the seventh day after irradiation.Results Compared with the irradiation alone group,the treatment of mice with ferulic acid 90 mg· kg-1 · d-1 increased the number of white blood cells in peripheral blood at 3,10,15 and 22 d after irradiation (t =2.267,2.399,1.945,2.828,P ＜ 0.05).Treatment with mice with ferulic acid 90 mg· kg-1 · d 1 decreased the micronuclei rate of erythrocytes in irradiated bone marrow (t =4.013,P ＜ 0.05),increased the clone numbers of CFU-E,BFU-E and CFU-GM of hematopoietic progenitor cells (t =2.366,2.953,3.115,P ＜0.05),improved the relative expression of the Thbd protein in bone marrow and the HMGB1 protein in nuclear (t =17.75,23.39,P ＜ 0.01).Conclusions Ferulilc acid could protect the bone marrow hematopoietic of mice exposed to irradiation by regulating the expressions of Thbd and HMGB1 protein,and then accelerate the peripheral cells recovery.

Objective To understand and analyze the individual dose level of occupational exposure of medical radiation workers in China in 2015,and to provide the data and scientific basis for the prevention and control of occupational radioactive disease.Methods By using the "Occupational health of Radiation workers management system-external exposure of personal monitoring",the individual dose monitoring results and other related data of medical workers were collected and analyzed statistically.Results Altogether,data for 214,860 persons have been collected in 2015.The average annual individual effective dose was 0.429 mSv.The average annual individual dose of diagnostic radiology,dental radiology,nuclear medicine,radiotherapy,interventional radiology and others,six categories of occupational groups were 0.423 mSv,0.326 mSy,0.538mSv,0.321 mSv,0.542 mSv and 0.407 mSv,respectively.The difference of average annual individual effective dose of six categories of occupational groups was statistically significant (P ＜ 0.001).The average annual individual dose of nuclear medicine and interventional radiology were significantly higher than those of other occupational categories (P ＜ 0.05).Conclusion The average annual individual effective dose of radiation workers meets the national standards.The exposure dose of nuclear medicine and interventional radiation workers is relatively high.To protect their occupational health,the relevant radiation protection measures and facilities should be strengthened.

OBJECTIVE:To study the effect of ferulic acid on damage of human umbilical vein endothelial cells (HUVECs) from their exposure to ionizing radiation METHODS:HUVECs were exposed to60 Co gamma ray at the radiation doses of 4-16 Gy. Cells viability as determined by the MTS assay was examined 48 h after irradiation to select the appropriate irradiation dose. Expression levels of Thbd and γH2AX were examined by western blot assay with the total protein of HUVEC extracted at 1,3,6,12,24 and 48 h after irradiation. In addition,HUVEC received 0.001-1μmol/L ferulic acid at 2 h before irradiation. Cell viability and expression of Thbd and γH2AX protein were determined at 48 hours after irradiation. RESULTS:Compared with the non-irradiated group,cell viability at 48 h after 10 Gy irradiation was decreased by 30％ (P<0.05). Thbd expression was reduced to about 0.6-fold (P<0.05) at 1 h after irradiation.γH2AX was increased about 5 times (P<0.05) at 48 h after irradiation. Addition of 0.1 to 1 μmol/L ferulic acid increased the viability of irradiated HUVEC and the protein expression of Thbd at 1 h after irradiation,and decreased the expression ofγH2AX at 48 h after irradiation. CONCLUSION:Ferulic acid in the concentration of 0.1-1 μmol/L played a role in radiation protection since it promoted cell vitality and proliferation by increasing the expression of Thbd protein and decreasing the expression of γH2AX protein.

Objective:To study radiation dosimetry of stereotactic gamma ray radiotherapy system with dynamic rotating of different types on the same platform of Monte Carlo simulation.Methods: 1)OUR-QGD stereotactic gamma ray radiotherapy system and LUNA whole body gamma ray radiotherapy system were selected as the representative model according to the focus mode of stereotactic gamma ray radiotherapy system. 2)MC modeling were implemented based on EGSnrc, respectively. 3)The distributions of dosage at focus were detected by using EBT3 film and 160 mm mode of plexiglass sphere so as to verify MC mode. 4)The relative research of dosimetry was implemented by using the verified mode. Results: The simulation results of the Monte Carlo model of the OUR-QGD stereotactic gamma ray radiotherapy systems and LUNA whole body gamma ray radiotherapy systems were compared with the corresponding result of experimental measurements, respectively. Under the different conditions of collimator, all of the Full Width at Half Maximum(FWHM) deviation of the dose distribution was less than or equal to 1 mm. And the result of the comparison between output factor of MC simulation and data from manufactory revealed that all of deviation were in ±4%, and the deviations were further analyzed.Conclusion: The research of Monte carlo simulation of radiation dosimetry about stereotactic gamma ray radiotherapy system with dynamic rotation can provide important reference and basis for quality control of radiation dosimetry of stereotactic gamma ray radiotherapy system of different type in clinical application at present.

目的监测2015年北京地区室外近地面空气气溶胶中γ放射性核素组成与空气污染的关系。方法采用便携式Staplex TF1A型大流量空气采样器采集室外近地面空气气溶胶,滤膜为Whatman公司生产的空气监测用滤膜,使用实验室HPGeγ能谱仪测量分析气溶胶滤膜样品。结果样品中检测出的放射性核素包括 212 Pb和7Be,其中 212 Pb的活度浓度大约在10 -2 Bq/m~3的量级;~7Be的活度浓度大约在10-3Bq/m~3的量级;其他放射性核素均未检出。结论经与空气污染等指数进行分析发现, 212 Pb的近地面空气中放射性核素活度浓度水平与PM2.5、PM10和空气污染指数的相关性有统计学意义,成正相关关系。~7Be的近地面空气中放射性核素活度浓度与空气污染指数的相关性有统计学意义,是弱负相关关系。

目的 初步研究并建立块型建材中氡射气系数的快速测量方法.方法 本工作以块型加气混凝土为研究对象,建立氡射气输运理论模型、采用测氡仪和密闭装置测量累积氡浓度、计算氡射气系数,并与标准测量方法进行比对.结果 该方法与标准方法的测量结果无显著性差异,表明了较高的可靠性.结论 研究建立的快速测量方法可较大缩短测量时间,利于建材氡放射性危害的评价,是其放射性危害防控体系的有益补充.

As part of a regional International Atomic Energy Agency-coordinated research project with the support from the National Health and Family Planning Commission of China, 22 laboratories participated in the intercomparison in cytogenetic dosimetry in China. Slides for chromosomal aberrations were prepared by the Department of Radiation Epidemiology, National Institute for Radiological Protection, which organized the exercise. Slides were sent to the other participating laboratories through Express Mail Service. For estimates of dose, each laboratory scored the frequency of dicentrics plus centric rings chromosomes. The whole blood samples were irradiated with 60Co γ-rays (1.3 Gy, 2.4 Gy and 1.5 Gy, 2.6 Gy). Each laboratory got one group of the slides. Ten of the 44 estimates of dose fell within ±5% of the true physical dose, 12 fell within ±5–10%, 9 fell within ±10–15%, 12 fell within ±15–20%, while only one sample fell ± >20%. The evaluation of the respective dose was achieved by 21 laboratories.

Objective To investigate the levels and distribution of radon concentrations in groundwater in some representative cities in China,and estimate the effective dose from inhaled radon released from domestic groundwater.Methods A total of 12 cities in 7 provinces (municipalities) were selected,including Beijing,Inner Mongolia,Ningxia,Shaanxi,Henan,Liaoning and Heilongjiang.In total,73 water samples from groundwater supply were taken.Radon concentrations in water samples were determined by using a continuous radon monitor with air-water exchanger.Results The average radon content in groundwater for drinking was 11.8 Bq/L in 12 cities in 7 provinces,ranging from 1.0 to 63.8 Bq/L.The radon concentrations in 37％ water samples exceeded 1 1.1 Bq/L,the safe limit recommended for drinking water by the United States Environmental Protection Agency (EPA).The radon contents in all of the water samples was lower than the reference level 100 Bq/L recommended by World Health Organization (WHO).The average annual effective dose arising from inhaled radon released from groundwater was 29 μSv (2.4 to 160 μSv).Conclusions Generally,the effective dose from inhaled radon released from groundwater is negligibly low.However,in some areas dominated by granite bedrock,the dose contribution from radon released from groundwater to residents should be routinely monitored.

The activity levels of long-lived radionuclides in minerals have received more and more concern for the public health. The inductively coupled plasma mass spectrometry was used to measure the content of uranium and thorium in 60 mineral samples collected from 16 mines of seven provinces in China. The contents of uranium and thorium ranged0.17 ± 0.04 lg g-1to 15.3 ± 2.39 lg g-1, and 0.19 ± 0.04 lg g-1to 19.6 ± 7.56 lg g-1, respectively. The highest levels of U and Th contents were found in aluminum ore,whereas the lowest was found in antimony and copper ores.

This study represents a total of 245 samples collected. The activities of (238)U, (228)Ra, (226)Ra, (40)K and (137)Cs were determined in samples of vegetables, tea, cereal (rice, wheat and corn), meat, poultry, freshwater product, seafood and seaweed that collected from the 30km safety zone of the Nuclear Power Plants (NPPs) area. All the samples radionuclide activities were quantified by using High Purity Germanium (HPGe) gamma spectrometry. The geometric mean concentrations (Bqkg(-1) wet weight) for (238)U, (228)Ra, (226)Ra, (40)K, and (137)Cs in all investigated foodstuffs samples, are 0.13, 0.16, 0.11, 68 and 0.02, respectively. The arithmetic mean concentrations (Bqkg(-1) wet weight) for (238)U, (228)Ra, (226)Ra, (40)K, and (137)Cs in all investigated foodstuffs samples, are 0.34, 0.65, 0.32, 111 and 0.09, respectively. Results of this study were compared with others, the measured values are the same with those of a previous investigation. Radiation doses due to the consumption of these foodstuffs to humans are estimated to comprise around 37-46% of the annual dose limit for public.

目的 比较γ能谱仪刻度用标准样品探测效率的差别,为样品测量分析中的效率校正提供参考.方法 利用水、鱼肉灰、蔬菜灰和大米灰四个标准样品,在同一台HPGeγ能谱仪进行测量分析,比较效率值的相对偏差.结果 水样品与生物灰样品由于样品的几何形状和样品介质不同,导致各个能量点的效率值都有较大差别.三个生物灰样品仅装样密度不同,各个能量点的效率值略有差别.结论 γ能谱仪刻度时应首先保障被测样品与效率刻度用样品在几何形状和介质上一致,其次是样品装样密度应尽量一致,当密度不一致时效率的偏差在低能部分表现较大,应注意样品中低能区的自吸收校正问题.

Purpose Through the Monte Carlo (MC) simulation of 6 and 10 MV flattening-filter-free (FFF) beams from Varian TrueBeam accelerator, this study aims to find the best incident electron distribution for further studying the small field characteristics of these beams. Methods By incorporating the training materials of Varian on the geometry and material parameters of TrueBeam Linac head, the 6 and 10 MV FFF beams were modelled using the BEAMnrc and DOSXYZnrc codes, where the percentage depth doses (PDDs) and the off-axis ratios (OARs) curves of fields ranging from 4 × 4 to 40 × 40 cm 2 were simulated for both energies by adjusting the incident beam energy, radial intensity distribution and angular spread, respectively. The beam quality and relative output factor (ROF) were calculated. The simulations and measurements were compared using Gamma analysis method provided by Verisoft program (PTW, Freiburg, Germany), based on which the optimal MC model input parameters were selected and were further used to investigate the beam characteristics of small fields. Results The Full Width Half Maximum (FWHM), mono-energetic energy and angular spread of the resultant incident Gaussian radial intensity electron distribution were 0.75 mm, 6.1 MeV and 0.9° for the nominal 6 MV FFF beam, and 0.7 mm, 10.8 MeV and 0.3° for the nominal 10 MV FFF beam respectively. The simulation was mostly comparable to the measurement. Gamma criteria of 1 mm/1 % (local dose) can be met by all PDDs of fields larger than 1 × 1 cm 2 , and by all OARs of no larger than 20 × 20 cm 2 , otherwise criteria of 1 mm/2 % can be fulfilled. Our MC simulated ROFs agreed well with the measured ROFs of various field sizes (the discrepancies were less than 1 %), except for the 1 × 1 cm 2 field. Conclusions The MC simulation agrees well with the measurement and the proposed model parameters can be clinically used for further dosimetric studies of 6 and 10 MV FFF beams.