Objective To investigate the current situation of MRI quality control in forty grade 3 and ifrst-class hospitals in Beijing. Materials and Methods Analyzed the MRI iflms of brain, cervical vertebra, lumbar vertebra, knee joint, and pelvis through combined selective examinations with on-site inspections, in order to judge whether the MRI quality can meet the requirements issued by Beijing Municipal Bureau of Healthy Center For Medical Imaging Quality Control and Improvement. Results Quality control of MRI is generally good in grade 3 and ifrst-class hospitals in Beijing, problems mostly come from MRI artifacts, magnetic ifeld shimming, fat suppression, inappropriate FOV, as well as problem with iflm viewer. Conclusion Quality control of MRI iflm is the premise of hardcopy image sharing in Beijing.

Objective To analyze the present situation of the application of CT in third-grade hospitals in Beijing. Subjects and Methods Analyzed the application conditions of CT equipment in 42 third-grade hospitals in Beijing, including the brand, model, quantity, scanning technical requirements, image requirements, film observation requirements, and radiation dose. Results CT scanning in these hospitals are in good condition, problems mostly come from the scanning mode, image quality, dose control, and the use of films. Conclusion The usages of CT in third-grade hospitals in Beijing are reasonable, but strengthened monitoring and continuous improvement of image 100053, China; 3. Fu Wai Hospital, Chinese Academy of Medical Science, Beijing 100037, China;4.Beijing Tongren Hospital, Capital Medical University, Beijing 100005, China; 5. People’s Liberation Army Air Force General Hospital, Beijing 100142, China quality are still necessary.

Objective This study is to investigate the relationship between different coronary computed tomography angiography (CCTA) examination modes and the radiation dose, in order to achieve as low as reasonable radiation dose, guiding and regulating the legitimation and optimization of coronary CTA examination. Materials and Methods Analyzed the effects of different models of MSCT and different scanning modes for coronary CTA on radiation dose in 30 tertiary hospitals of Beijing. All cases were divided into different groups according to CT models (general 64-slice CT and post 64-slice CT) and scanning modes (prospective ECG-triggering axial acquisition mode, retrospectively ECG-gated spiral data acquisition mode and prospectively ECG-gated high-pitch spiral acquisition mode). Achieved the mean values of CTDI, DLP and ED respectively and using independent sample t-test to analyze the radiation dose difference between different models and scanning modes. Results The statistical data on CTDI, DLP and ED of the post 64-slice CT is(27.61±19.61)mGy、(412.56±328.74) mGy?cm、(5.78±4.60) mSv, respectively, lower than those of the general 64-slice CT (57.09±27.58 ) mGy、(950.93±552.91) mGy?cm、(14.53±8.81) mSv, and the difference was statistically significant (P<0.05). The mean values of CTDI,DLP and ED were (17.98±11.27) mGy、(229.63±158.31) mGy?cm、(3.24±2.20) mSv in the prospective ECG-triggering axial acquisition mode group, retrospectively, while the mean values of CTDI, DLP and ED in ECG-gated spiral data acquisition mode group were (50.89±25.01) mGy、(839.80±469.56) mGy?cm、(12.40±7.42) mSv, respectively , the difference was statistically signiifcant (P<0.05). Conclusion Post 64-slice CT and low-dose scanning mode are both helpful for radiation dose reduction in coronary CTA.

2013年,我们迎来了《中华放射学杂志》创刊60周年的庆典.让我们衷心祝愿《中华放射学杂志》60年来取得的丰硕成果. 当我们浏览、回顾《中华放射学杂志》60年刊登的论文时,深深地感受到了《中华放射学杂志》60年艰辛而辉煌的历程,同时也展现了我国医学影像学发展的历程,其中包括了影像技术学的发展.

<正>本书紧跟学科发展,采用词条和词条详解的形式,对X线摄影成像技术、乳腺X线摄影与质量控制、CT成像技术、MR成像技术、数字减影血管造影与介入放射学技术、放

目的 探讨数字X线摄影中混叠效应的产生原因及其对影像质量的影响.方法 使用Kodak CR900系统分别对矩形波测试卡和固定滤线栅成像.测试卡铅条在平行于激光扫描方向和呈45.角的放置方式下分别成像,观察两种影像对分辨率测试卡的显示情况.使滤线栅铅条的方向在平行和垂直于激光扫描方向时分别成像,在显示器上使用不同的放大率对滤线栅影像进行观察,并比较两种影像外观的差异.结果 测试卡影像上,3.93线对/mm以上频率的铅条影无法相互分辨,因此尼奎斯特频率为3.93 LP/mm.但在测试卡45°放置的影像中,频率为4.86 LP/mm的铅条仍能相互分辨.滤线栅铅条平行于成像板的激光扫描方向时,最终影像中显示出明显的条纹影.在显示器上使用不同的放大率观察时,栅条形成的条纹影宽度和方向都发生明显变化.铅条与激光扫描方向垂直时影像中的条纹影显著减弱.结论 CR应用中混叠效应会对数字影像产生不利影响,应根据设备的极限分辨率选择适当的固定滤线栅,栅频率应大于尼奎斯特频率.在摄影中,滤线栅的铅条方向应与成像板的激光扫描方向相垂直.在显示器上观察固定滤线栅摄影影像时,建议使用原始图像的整数倍的放大率.

Objective To investigate the relationships between CR image pixel values and exposure factors (kVp,mAs), thickness of exposed subject, and those between conventional screen-film optical density and exposure factors (kVp,mAs), thickness of exposed subject. The relationships of these two kinds of energy response were compared. The feasibility of using CR image pixel values and measure values of IP mean incident exposure as parameters for setting up phototimer was studied. Methods Homogeneous acrylic phantoms 10, 15 and 20 cm thick were imaged with a traditional X-ray system and a CR system at 50-90, 70-120, 90-140 kVp and AEC density grade -2. Automatic exposure responses of the two systems at various tube voltages, same exposed subject thickness and grade selection were compared. Grid were used simultaneously for all radiography. Incident IP exposures were measured with an ionization chamber. Results Under the conditions of meeting clinical diagnostic requirements, the exposure of CR system was two times of that of rare earth screen-film system approximately. Tube voltages vs pixel value curves were similar to those of tube voltages vs exposure curves in CR system. When the thickness of the projected subject remained 10 cm, the screen- film density difference in 50-90 kVp was 1.21, and the pixel value difference was 270. When 20 cm thick, the density difference in 90-130 kVp was 0.30, and the pixel value difference was 100. When 15 cm thick, they were 0.62 and 160 seperately. Conclusion The speed value of Kodak CR 900 system is closely similar to that of medium screen-film systems. The exposure index value in flat field image and IP mean incident exposure could be used as factors to setup phototimer of AEC. The regularities between film density and kVp, pixel value and kVp, as well as differences in them, are important to the callibration of AEC system.\;

目的对介入诊疗中工作人员辐射防护与安全的主要影响因素进行测定与研究,对相关影像因素的特点加以探讨.方法分别测定影像增强器照射野的大小、管球角度改变、冠脉造影中不同手术体位对受检者和第一术者体表入射剂量的影响,对介入诊疗中重要站立区域的辐射剂量进行测定与评价,测定和研究介入诊疗区域内辐射场的分布情况.结果成功测量各主要影响因素的相关数值.结论影像增强器照射野越大,受检者所受剂量越小,影像增强器照射野的改变对第一术者所受剂量的影响无明显规律.对第一术者而言足位辐射剂量最大,头位次之,其他体位辐射剂量相对较小.冠脉造影中正足位的面积剂量乘积值最大,其次为右足位.对第一术者的剂量贡献绝大部分是距地面高60-80cm处剂量高区散射束所致.一般的,被检者左上辐射场的强度最高.被检者右侧一般为手术人员站立处,必须加以防护.在介入手术过程中一定不要忽视防护装置的作用.

Objective To measure and evaluate the distribution feature of radiation dose at the conventional puncture plane in invasive diagnosis and treatment area, and depict the corresponding isodose curve. Methods A platform was built at the conventinal puncture plane in invasive diagnosis and treatment area.By taking the center of X_ray source as the measurement center coosing the conventinal antero_posterior and lateral basic postures and choosing one measurement site for every 0.1 m in 8 directions,measurements were carried out for three times at every measurement point and the arithmetic means,were calculated,corrected and converted to mGy/h. Results We successfully measured doses of X_ray radiation in invasive diagnosis and treatment area,and depicted the distribution curve. Conclusion Generally, the left_superior radiation field of the patient is the strongest,where the physician interns always stands to install a pacemaker.Therefore,the latter should be alerted.The practising physicians and interns often stand there to watch the performance.They should avoid standing there.Nurses always stand in the left_inferior field of the patient doing fluid infusion and adding drugs into the fluid.They should be aware of the danger.Electrophysiology technicians often stand on the left_foot side of the patient,although the radiation dose in not large,they should take care too.Operators always stand on the right side of the patient.They should be protected.;

目的:调研北京地区所用的CR乳腺摄影影像质量情况,为卫生行政管理部门决策提供实测参考数据.材料与方法:在同样条件下分别用屏/片、CR摄取同一个标准乳腺模体的影像,参照美国MQSA标准,由临床专家和影像检测技术人员盲评其空间分辨率和可分辨微钙化点簇数、纤维条数及半球状肿块数.结果与讨论:富士(FUJI)公司的FCRPROFECTCS系统的影像质量和柯达(KODAK)公司最新屏/片的影像质量比较接近:空间分辨率7～8Lp/mm为屏/片影像的一半,其他三项则与屏/片影像持平.FCR PROFECT CS系统DQE较高,用屏/片摄影一半剂量摄影,临床专家已区分不出是屏/片影像还是FCRPROFECTCS系统的CR影像;所调查的其他型号CR影像质量均比屏/片系统差,可分辨微钙化点的尺寸大于0.2mm,这些类型CR不适合用于乳癌普查.

Objective To determine the dose distribution and maximum skin dose to the patient for four interventional procedures: coronary angiography (CA), hepatic angiography(HA),radiofrequency ablation (RF) and cerebral angiography(CAG) ,and to estimate the definitive effect of radiation on skin. Methods Skin dose was measured using LiF: Mg,Cu,P TLD chips. A total of 9 measuring points were chosen on the back of the patient with two TLDs placed at each point, for CA,HA and RF interventional procedures ,whereas two TLDs were placed on one point each at the postero-anterior(PA) and lateral side (LAT) respectively, during the CAG procedure. Results The results revealed that the maximum skin dose to the patient was 1683.91 mGy for the HA procedure with a mean value of 607.29 mGy. The maximum skin dose at the PA point was 959.3 mGy for the CAG with a mean value of 418.79 mGy; While the maximum and the mean dises at the LAT point were 704 mGy and 191.52 mGy, respectively. For the RF procedure the maximum dose was 853.82 mGy and the mean was 219.67 mGy. For the CA procedure the maximum dose was 456.1 mGy and the mean was 227.63 mGy. Conclusion All the measured dose values in this study are estimated ones which could not provide the accurate maximum value because it is difficult to measure using a great deal of TLDs. On the other hand , the small area of skin exposed to high dose could be missed as the distribution of the dose is successive.;

受试者操作特性解析(receiver operating characteristic analysis, ROC解析)是以通讯工程学中的信号检出理论(signal detection theory, SDT)为基础,以心理临床评价的受试者操作特性曲线的解析和数理统计处理为手段的1种评价方法,也称ROC曲线法,属主观评价法[1].

Objective To study quality control methods of automatic processor and its dynamic changes. Methods Using 5 types of automatic processors manufactured by Kodak, Agfa or Konic company installed in 10 hospitals in Beijing area, the effect of quality control management parameters, development temperature, test time and frequency every day, radiograph quality are studied. And QC strip, QC standard, linking program of management of radiographs, quality management program of the processor are studied and established. Results By the methods presented above, we can obtain single and multiple management parameters chats, contrast response curve of the processor, dynamic curves of test time and test frequency, test point trace and quality dynamic curves, regular quality management chat and linking program. Conclusion An integrated control program for quality control of automatic processor is required, that is obeyed the relative standard, and may be corrected in practice.

目的从临床诊断要求、病人辐射剂量及所需成像技术条件等三方面，探讨建立胸部照片综合评价的方法和标准。方法（１）取１０份正常胸片，并参考文献，确认胸部正位照片评价区域的划分及诊断要求的标准；（２）通过男女各２０例胸部ＣＴ扫描，计算出肺野与纵隔部比例；（３）取１２５ｋＶｐ条件下摄影胸片１００例，测量各评价区的标准密度值；（４）测量男女共４７８例正常成人体表入射剂量。结果（１）从诊断要求出发确认７个评价点，物理因素确认为４个评价因素，并给出了评价标准；（２）建立综合评价方法；（３）初步探索了中国正常成人标准身高、体重、体表入射剂量。结论从综合评价概念出发，就胸部正位影像评价方法和标准做了探讨，为今后建立全国正式标准提供了方法和思路。

目的建立以焦点胶片距离的改变，取得Ｘ线阶段曝光的屏片体系感光测定方法。方法利用常规Ｘ线机在焦点胶片距离４０～３２０ｃｍ的范围内，取７个距离曝光点，对ＯｋａｍｏｔｏＤＭＳ（蓝屏）／ＦｕｊｉｎｅｗＲＸ（感蓝片）及ＦｕｊｉＨＲＲｅｇｕｌａｒ（绿屏）／ＦｕｊｉＨＲＮ（感绿片）两种屏片体系样本做感光测定，绘制特性曲线、斜率密度曲线，求取特性值。同时与感光仪和铝梯定量测定法（Ｂｏｏｔｓｔｒａｐ法）作比较。结果（１）测试用Ｘ线机的平均管电压值、高压纹波率、输出剂量、曝光时间等四项指标的变动系数均小于０．０２，重复性良好。（２）Ｘ线强度与距离平方在测试距离内呈线性关系，倾斜值为－２．０４，证明本实验中的“距离反平方定律”成立。（３）实验证明，距离法的曝光条件确定在６０～８０ｋＶｐ，ｍＡｓ以在距离８０．３ｃｍ［相对曝光量对数（ＬｏｇＲＥ）＝１．２］时得到２．０＋本底灰雾的密度值为调节指标，总滤过３．０ｍｍＡｌ＋０．５ｍｍＣｕ（三相工频机）或３．５ｍｍＡｌ（中频机）。结论距离法与感光仪法、时间阶段曝光法、铝梯定量法相比，重复性较好，曝光机制符合Ｘ线摄影实际，便于统一。

目的评价不同屏片组合下Ｘ线照片影像的颗粒性，以期掌握照片颗粒性的客观评价方法，并获得影响影像颗粒度的相关因素。方法利用显微密度计对测试样本进行扫描，通过均方根（ｒｏｏｔｍｅａｎｓｑｕａｒｅ，ＲＭＳ）值的计算，对不同屏片组合的Ｘ线影像进行颗粒度的物理评价。结果通过测试和数据整理，得出颗粒度与管电压、密度、对比度及清晰度的关系。结论Ｘ线照片影像颗粒度随着管电压、清晰度和对比度的升高而升高，随密度的升高而降低