目的 研究口腔颌面锥形束计算机断层扫描(CBCT)受检者的牙周辐射剂量规律,指导口腔CBCT临床进行合理辐射防护.方法 热释光剂量计(TLD)126支分为42组(3支／组),按照无辐射防护(1~21组)以及有辐射防护(22~42 组)情况分置于仿真人头颈体模检查部位和非检查部位体表的对应测试点进行测试.口腔CBCT检查后读出器读出每个TLD入射体表剂量,3支／组取平均值后转换成有效剂量.结果 在无和辐射防护条件下,口腔CBCT受检者检查部位体表对应测试点的辐射剂量基本一致(P＞0.05);非检查部位体表对应测试点的辐射剂量,辐射防护小于无辐射防护情况(P＜0.05).结论 口腔CBCT检查要优化检查技术,对受检者检查部位邻近非检查部位进行专业辐射防护.

目的:研究口腔上、下颌正切牙摄影受检者辐射剂量特征,指导口腔摄影进行合理的辐射防护.方法:编号热释光剂量计(TLD)44组(3支/组)分4组(上颌正切牙为1～11组和12～22组;下颌正切牙为23～33组和33～44组),按序置于仿真人头颈体模体表对应测试点.在无辐射防护和有辐射防护情况下,分别对头颈体模的上、下颌正切牙进行摄影.读出器读出每个TLD入射体表剂量,3支/组取平均值,转换成有效剂量.秩和检验统计分析,P<0.05为差异显著.结果:口腔上、下颌正切牙照射野范围辐射剂量相对最大.无辐射防护和辐射防护条件下,口腔上、下颌正切牙检查部位体表对应测试点辐射剂量基本一致,秩和检验P﹥0.05,无统计学差异;非检查部位体表对应测试点辐射剂量,辐射防护小于无辐射防护情况,秩和检验P<0.05,统计学差异性显著.结论:口腔上、下颌牙齿正切牙摄影检查须优化技术条件,对非检查部位重要腺体要进行专业性辐射防护.

目的 比较口腔计算机曲面断层摄影(computed orthopantomography,COPT)和口腔颌面锥形束立体断层扫描(cone beam CT,CBCT)两种扫描方式受检者入射体表剂量(Entrance Surface Dose,ESD)的大小.方法 用热释光剂量法(TLD)模拟测量两类口腔CT在进行COPT和CBCT扫描时所致受检者的入射体表剂量.实验时将热释光剂量计元件布放于人体仿真头部模体的12个关注点位,采用RGD-3B型热释光剂量仪对元件进行剂量测量.结果 A设备两种模式在COPT临床常用照射条件下,CBCT受检者入射体表剂量高于COPT受检者(P＜0.01),二者剂量比为1.2 ～9.8倍;B设备两种模式在各自临床常用照射条件下,CBCT受检者入射体表剂量高于COPT受检者(P＜0.01),二者剂量比为1.8 ～ 14.4倍.结论 口腔科医生应正确认识COPT和CBCT两种检查方法对受检者的辐射剂量,合理选用照射条件,严格掌握适应症,指导受检者正确使用个人防护用品,将辐射危害降低到可合理达到的尽可能低的水平.

目的:研究口腔COPT受检者牙周辐射剂量特征,对受检者行合理辐射防护.方法:热释光剂量计(TLD)42组(3支/组),无辐射防护(1～21组)和辐射防护(22～42组)时分别置于仿真人头颈体模体表对应测试点,依次行口腔COPT检查用读出器读出TLD入射体表剂量,3支/组取平均值后转换成有效剂量.统计分析采用秩和检验,P<0.05为差异显著.结果:无和有辐射防护条件下,口腔C O P T受检者检查部位体表对应测试点的辐射剂量秩和检验P>0.05,统计学上无显著性差异;非检查部位体表对应测试点辐射剂量,辐射防护时小于无辐射防护,秩和检验P<0.05,统计学差异显著.结论:口腔COPT检查要优化检查技术条件并对受检者进行专业性辐射防护.

Objective To analyze the performance differences of CT scanners with different detector rows between different manufacturers,and to provide the basis for the rational allocation and use of these CT scanners.Methods According to the result from the sentinel surveillance in 2014,a total of 148 medical institutions were equipped with CT scanners in 16 districts of Beijing,including general hospital(53),cancer hospital(5),TCM hospitals(25),children′s hospitals(2),community hospitals(30)and other specialized medical institutions(33).According to the principle of simple random sampling,40 medical institutions are selected,including 14 general hospitals,1 cancer hospital,7 Chinese medicine hospitals,1 children′s hospital,8 community hospitals and 9 other specialized medical institutions.A total of 141 CT scanners are selected from all CT sets of the selected medical institutions from 2012 to 2014.According to GB 17589-2011 X-ray computed tomography device quality assurance testing status test,four parameters related closely to image quality were tested,including CT value(water),noise,high contrast resolution,and low contrast detectability.Results No significant differences were found in CT value(water),noise and low contrast detectability among CT scanners produced by different manufacturers(P＞0.05),whereas high contrast resolution was found to have a remarkable difference(χ2＝34.706,P＜0.05).Significant differences were found in noise,high contrast resolution and low resolution detectability between the CT scanners with ＜64 detector rows and ≥64 detector rows(χ2＝6.978,10.040,15.973,P＜0.05).However,there is no difference in CT value(water)(P＞0.05).For less-than-64 detector row CT scanners,no significant difference was found in CT value(water),noise and low contrast detectability among different manufacturers(P＞0.05).only high contrast resolution differed remarkably(χ2＝9.941,P＜0.05).For more-than-or equal-to-64 detector row CT scanners,CT value(water)and noise have no differences among different manufacturers(P ＞0.05),whereas,there were significant difference in high contrast resolution and low contrast detectability(χ2＝31.376,32.967,P＜0.05).Conclusions There were a few differences in the performance testing of CT scanners from different manufacturers,and the less-than-64 detector row CT scanners have advantages in noise and low contrast detectability compared with the more-than-64 detector row CT scanners,whereas the latter have advantages in high contrast resolution and scanning time,allowing its wider application in medical institutions with more special diseases.

[Objective] By analyzing the testing results on the quality of medical diagnostic X-ray equipments in Beijing from 2010-2014,to understand the quality control status of the medical diagnostic X-ray equipment in this region,improve the level of quality assurance,and promote and guide the development of radiation diagnosis and prevention work.[Methods]The performance test reports of 727 X-ray cameras and 274 X-ray perspective apparatus in medical institutions at all levels in Beijing were collected from 2010-2014,to synthesize and analyze the performance indexes.[Results]The qualified rate of X-ray cameras in 2010 was significantly lower than that in other years,and the qualified rate of screen cameras was the lowest,which was only 66％.In the year of 2012,the qualified rates of cameras and X-ray perspective apparatus reached 95％.[Conclusion]The radiological diagnostic equipments which are investigated distribute in medical institutions at all levels,involving various districts and counties of this municipality.The results can reflect the quality control of the X-ray cameras and the X-ray perspective apparatus of the city truly and objectively.The performance of medical X-ray equipments in Beijing is not optimistic at the early detection.The qualified rate is significantly improved after debugging the equipment every year.The results prove that it is necessary to strengthen the maintenance of the radiological diagnostic equipment,and to carry out the state examination and stability testing.

目的 掌握LB6008型六路低本底α、β测量仪性能指标,准确测量样品中总α、总β放射性体积活度.方法 使用239 Pu、90Sr-90Y工作源和241Am、40K粉末源对仪器进行效率刻度,对本底计数率、串道比及效率稳定性进行分析,依据GB/T 11682-2008和厂家指标进行评价.结果 α本底计数率≤0.07计数/(cm2.h),β本底计数率≤5.1计数/(cm2.h),各路α探测器2π探测效率比均＞80％,β探测器2π探测效率比均＞50％;241 Am α源探测效率为(5.62±0.33)％,40K β源探测效率为(26.22±2.11)％,5d内探测效率变化≤4.58％;α射线对β道的串道比≤1.6％,β射线对α道的串道比≤0.12％;本底月稳定性实际测量值均在-Nh±3δ可接受范围内,95％的测量值在-Nb±2δ目标值范围内.结论 该测量仪的基本性能指标均达到国家规定的Ⅱ级标准,适于样品总放射性水平的常规测量.

目的 掌握北京市医用X射线诊断设备质量控制的基本状况,以采取相应措施获得稳定、高质量的医学影像,提高医疗诊断水平并减少受检者的辐射剂量.方法 依据2015年度医疗机构医用辐射防护监测工作方案的要求,选择62家医疗机构中运行的234台放射诊断设备为研究对象,确定其关键性能指标,使用Unfors Raysafe X2 X射线多功能检测仪,Catphan 500型CT成像性能模体等仪器设备,依据有关国家标准进行检测和评价.结果 234台放射诊断设备总合格率为93％,其中屏片X射线摄影机和影像增强器透视机的合格率均为92％,DR X射线摄影机的合格率为99％,CR成像系统的合格率为62％,CT的合格率为98％,数字乳腺X射线摄影机的合格率为75％.结论 北京地区放射诊断设备性能状况不容乐观,应进一步加强设备的质量控制检测.

目的 了解北京市生活饮用水、地表水总α、总β放射性本底水平及分布特点.方法 收集2011年-2014年北京市18个区县定点水源水以及其他方式获得的样品,共695件.采用国家标准方法对总α、总β放射性活度进行监测并对监测结果进行分析评价.结果 2011年-2014年北京市生活饮用水、地表水中总α放射性活度为0.007 Bq/L～1.74 Bq/L,总β放射性活度为0.003 Bq/L～1.18 Bq/L,总α、总β放射性活度水平＞90％的比例集中在(0～0.3)Bq/L和(0～0.5) Bq/L范围内.石景山区的生活饮用水和河湖水中总放射性水平整体偏高;大兴区和崇文区的河湖水总放射性水平整体偏高,生活饮用水总体上丰水期和枯水期差异不明显,地表水由于受外界因素影响较大,枯水期与丰水期没有明显的规律性.结论 北京市各区县生活饮用水的总α、总β放射性水平均低于GB5749-2006《生活饮用水卫生标准》规定的指导值.

Objective To study the patient surface radiation doses of oral COPT (Computed Orthopantomography) and CBCT (Cone Beam Computed Tomography) in order to take better radiation protection measures for full-oral clinical imaging examinations.Methods With application of the long pole ionization chamber and X-ray multi-functional detector, non-interventional methods were utilized to test the radiation dose of COPT and CBCT in the image receiver. Then, the patients’ oral surface air kerma and the air kerma rate were calculated according to the inverse square law between the radiation dose and the distance.Results Under the minimum technical conditions, the patients’ oral surface air kerma and the air kerma rate of CBCT and COPT were 0.21 mGy and 20.10 μGy/mAs in comparison with 0.13 mGy and 8.65 μGy/mAs respectively. While, under the maximum technical conditions, the patients’ oral surface air kerma and the air kerma rate of CBCT and COPT were 20.50 mGyvs 4.49 mGy and 178.2 μGy/mAsvs 21.02 μGy/mAs, respectively. And under commonly-used clinical technical conditions, the patients’ oral surface air kerma and the air kerma rate of CBCT (84~90) kV and COPT (62~70) kV were (16.61~18.62) mGy and (105.3~138.2) μGy/mAs in contrast with (0.97~3.12) mGy and (11.42~14.42) μGy/mAs, respectively.Conclusion The patient surface radiation dose of oral CBCT was higher than that of COPT. Three principles of radiation protection should be followed by oral clinical physicians and radiation physicians soas to make reasonable utilization of COPT and CBCT.

[目的]针对2011年3月11日日本福岛核事故,于2011—2013年采取相应的技术措施监测北京地区河、湖水与饮用水放射性污染水平,即该两类水中总α、总β放射性水平,确保饮用水的放射性污染水平不超过国家相关标准限值要求,为将来河、湖水的放射性水平可能发生的变化提供基础数据。[方法]制定采集计划,每年分别在枯水期和丰水期采集河、湖水和饮用水,样品的采集覆盖北京市16个区（县）,依据GB/T 5750.13—2006《生活饮用水标准检验方法》和GB 5749—2006《生活饮用水卫生标准》进行采集,采用相对比较测量法对水样总α、总β放射性进行测量分析。[结果]河、湖水样品中,总α放射性水平算术平均值范围为0.06~0.15 Bq/L,总β放射性水平平均值范围为0.20~0.25 Bq/L;饮用水样品中,总α放射性水平算术平均值范围为0.09~0.11 Bq/L,总β放射性水平平均值范围为0.08~0.10 Bq/L。[结论]2011—2013年北京地区河、湖水及饮用水在枯水期和丰水期的放射性水平均未超过国家生活饮用水卫生标准指导值。

目的 对比不同级别医院在使用数字X射线摄影及屏片X射线摄影对受检者进行摄影诊断时受检者剂量的差别.方法 采用热释光剂量计(TLD)法测量X射线摄影成人受检者入射体表剂量(ESD),选择20家医院年龄在20～70岁之间的受检者,男性体重在55～ 80kg之间,女性体重在50～70kg之间.测量部位包含头颅(PA、LAT)、胸部(PA、LAT)、腰椎(PA、LAT)及胸椎(PA、LAT).结果 共对961次摄影进行了调查,比较各级医院头颅(PA、LAT)、胸部(PA、LAT)、腰椎(PA、LAT)及胸椎(PA、LAT)的受检者体表剂量平均值,三级医院的受检者体表剂量平均值最小,分别为:0.28 mGy、0.37 mGy、0.32 mGy、0.10 mGy、2.59 mGy、1.99 mGy、4.02 mGy和4.73 mGy.结论 数字X射线摄影对受检者产生的剂量比屏片X射线摄影低;使用同种摄影设备对受检者产生的剂量中,三级医院最低,一级医院最高.

目的 掌握北京地区乳腺摄影受检者乳腺腺体平均受照剂量水平.方法 选取北京地区8家医疗单位542例受检者乳腺摄影时的条件,测量该条件下的空气比释动能,根据2011年度卫生行业科研专项的实施方案和欧盟(EC)等技术报告确定乳腺腺体平均剂量(AGD)的计算方法并计算.结果 乳腺腺体平均剂量平均值:CR(1.70 mGy)高于DR(1.27 mGy);就乳腺腺体平均剂量而言,钼靶/钼滤过＞钼靶/铑滤过＞铑靶/铑滤过＞钨靶/铑滤过.结论 不论是哪一级别的医院、何种采集模式、何种靶/滤过和体位,其乳腺腺体平均剂量平均值都不高于国家相关规定的2.0 mGy,但是个别医院存在乳腺腺体平均剂量过高和所有检查均采用同一个条件等的问题,应充分考虑乳腺摄影的防护最优化.

Objective: The basic status of quality control of apparatus of radio diagnosis and radiotherapy in Beijing were mastered to promote and guide the radiation protection work efficiently. Methods: 110 devices of radio diagnosis and radiotherapy from 38 typical medical institutions were selected as the research object, and their key performances were determined and tested by using the appropriate surveying instruments, then they were evaluated according to the national related technical criterions and protection standards. Results:The initial total qualified rate of the 110 sets of radio diagnosis and radiotherapy apparatus was 79.1%, and the initial qualified rates for radio diagnosis equipment, radiotherapy equipment and nuclear medicine equipment (PET and SPECT) were 82.5%, 70.8%and 66.7%respectively. The total qualified rate of all the devices was 95.5%after being debugged and rechecked. The local practical quality control conditions of radio diagnosis and radiotherapy can be reflected from the 38 medical institutions and their medical radiation equipments surveyed in Beijing. Conclusion:The initial examination of performances of the 110 medical radiation devices in Beijing is not optimistic, it is very necessary to strengthen the quality control testing of radio diagnosis and radiotherapy devices.

Objective To investigate the radiation dose levels to the adults examined from diagnostic exposure in Beijing. Methods The radiation doses to the examined individuals were measured by using individual diagnostic radiology equipments in 30 random hospitals from a total of 10 districts and suburban areas, including 1 182 samples of X-ray photography,542 samples of mammography and 410 samples of CT examination. Results 2 134 samples were measured in this study. The dose ranges of X-ray photography, CR, and DR were 0?4 -24?1, 0?3 -13?9 and 0?1 -15?9 mGy, respectively. The average dose range of glandular breast was 0?3-5?4 mGy. In 410 CT samples the value of CTDIw , CTDIvol and DLP were 28?1 - 96?3 mGy, 7?0 - 23?4 mGy, and 162?2 - 898?1 mGy·cm, respectively. Conclusions Several dose levels from diagnostic examination were higher than guidance level for medical exposure in GB 18871-2002,which should be noted.

目的 掌握北京地区放射诊断设备质量控制的基本状况,更好地推进和引导放射诊断防护工作的开展.方法 选定27家典型医疗机构中运行的80台放射诊断设备为研究对象,确定其关键性能指标,使用相应的仪器设备、依据有关国家技术规范与防护标准进行检测和评价.结果 80台放射诊断设备初检时的总合格率为82.5％,其中摄影机为76.7％、透视机为90％、CT机为93.3％,CR成像系统为73.3％,调试并经复检总合格率为97.5％.所调查的医疗机构及其设备客观反映了本地区放射诊断质量控制的实际状况.结论 北京地区放射诊断设备初检时的性能状态不容乐观,加强设备维护和质量控制检测是非常必要的.

Objective To explore the inlfuence of different anode/iflter combinations on image quality in digital mammography to choose the optimal anode/iflter combination for mammary glands with different densities. Methods The digital mammography of the phantom used to simulate human breast tissue was conducted under semi-automatic exposure mode through four kinds of anode/iflter combinations including Mo/Mo, Mo/Rh, Rh/Rh and W/Rh. The exposure conditions and radiation doses were recorded while the calcification points, ifbrous tissues and clumps of the phantom were evaluated through the analysis on phantom images according to ACR scoring standard.Results The skin incident dose and average mammary glandular dose of Mo/Mo were highest and those of W/Rh were lowest while those of Mo/Rh and Rh/Rh were moderate. The resolution ratio of clumps and ifbrous tissues of Mo/Mo was best and that of W/Rh was worst while that of Mo/Rh and Rh/Rh was moderate.Conclusion Different anode/iflter combinations are suitable for the digital mammography of mammary glands with different densities, which indicates that the actual thickness and density of breast should be considered to choose the exposure condition in clinic.

目的分析Leeds TO16模体在直接数字化成像系统(DR)影像质量评价中的应用和意义。方法采用不同的曝光剂量获得Leeds TO16模体图像,根据公式分别计算12组细节直径可达到的阈值对比度CT和探测指数HT,评价DR设备的低对比度细节探测能力(TCDD)。结果获得不同剂量下的探测指数,绘制探测指数图。结论采用Leeds TO16模体测试直接数字化成像系统的低对比度细节探测能力,可以定量和定性地评价成像系统的低对比度分辨力。

Objective To establish the nuclear monitoring system of organizing and managing so as to prevent Beijing from being affected by the Japanese Fukushima nuclear accident.Methods The controlling aims and emergency policies for Fukushima nuclear accident should be clarified.Some effective controlling approaches and programs were taken to organize and manage the nuclear monitoring based on the actual information of the nuclear accident,emergency response regulations and technology criterions.Results The rigorous system of organizing and managing provided guarantee in monitoring radioactive contamination resulting from the nuclear accident.All kinds of nuclear monitoring were undertaken successfully because of the excellent speciality diathesis and emergency response capacity of the controlling team.The social environment and public mood were put in the state of stabilization through information communication and modest public propagandizing.Conclusion The inherent function system of organizing and managing of BJCDC was operated in the course of defending the Japanese Fukushima nuclear accident which do harm to Beijing,and a lot of achievements were obtained from the accident by BJCDC,but a long-term project and some even more strong response measures still should be actualized.

目的 了解CR系统在北京市各级医疗机构中的应用状况和性能技术指标的合格情况,以便采取相应的措施,减少受检者的辐射剂量,获得稳定、高质量的医学影像.方法 采用非介入式的检测方法.结果 156台CR设备年检合格率27.6％,其中一级医院合格率最低(16.7％),二级和三级医院合格率分别为30.4％和32.8％.不合格设备113台,仅对53台进行了调试,首次调试合格率为73.6％.不合格项目主要是照射量指示校准和IP响应线性,其次是IP暗噪声.结论 IP板不能无限期重复使用,必要时更换新板,IP板和激光读取器应定期进行清洁保养,CR设备应安装在清洁防尘的房间内,新安装后必须进行验收检测,每年进行一次状态检测,每周、每月和每半年应对相关项目进行稳定性检测,并认真做好日常维护保养工作.