400万像素CCD-DR系统与常规X线摄影系统在胃癌诊断方面的比较

作者将1997年1月1日～2月28日来医院应诊,并被怀疑有胃癌的225例分成两组,一组112例,采用常规X线摄影系统检查,另一组为113例采用CCD-DR系统检查.使用400万像素CCD-DR(基于电荷耦合装置的数字X线摄影)系统,由X线发生装置、影像增强器、透视电视摄像机、图像处理器、监视器、激光打印机和一个CCD单元等组成.该系统每秒钟所获得的影像矩阵为2029×2044,每帧影像都将被自动处理,并经数个包括γ校正在内的计算机算法完善.     

400万像素CCD-DR系统与常规X线摄影系统在胃癌诊断方面的比较

作者将1997年1月1日～2月28日来医院应诊,并被怀疑有胃癌的225例分成两组,一组112例,采用常规X线摄影系统检查,另一组为113例采用CCD-DR系统检查。使用400万像素CCD-DR(基于电荷耦合装置的数字X线摄影)系统,由X线发生装置、影像增强器、透视电视摄像机、图像处理器、监视器、激光打印机和一个CCD单元等组成。该系统每秒钟所获得的影像矩阵为2029×2044,每帧影像都将被自动处理,并经数个包括γ校正在内的计算机算法完善。高分辨率的监视器可以持续观察,激光打印机也可以随时进行影像的硬拷贝,另外,该     

CR摄影与屏-片摄影的比较

目的探讨CR摄影与屏-片系统摄影曝光条件及对患者的X射线辐射剂量，评价CR摄影的应用价值。方法取本院CR照片和常规X射线摄影照片各2500份，由2位主管技师和1位副主任技师对照片按部位分组进行分析，统计出甲、乙、丙及废片率；并对乙、丙及废片产生的原因进行分析。结果①照片质量：CR摄影照片甲级片率63．6％，乙级片率27．2％，丙级片率9．2％，废片率0％；屏-片系统摄影照片甲级片率40．2％，乙级片率42．4％，丙级片率15．6％，废片率1．8％。②摄影条件的比较：CR数字摄影比屏．片系统摄影电压需提高1-6kV，曝光量高20％左右。结论CR数字摄影照片质量明显高于屏-片系统摄影，但曝光条件比屏-片系统高，相对增加了患者的X射线辐射剂量。     

直接数字化X线摄影在鼻骨摄影中的应用

目的探讨直接数字化X线摄影（direct digitized radiography，DDR）在鼻骨摄影中的应用价值。方法对100例DDR鼻骨侧位影像采用图像后处理方法中多级图像对比增益法，又称“交响乐”功能（muhi-scale image contrast amplification，MUSICA）、影像切割与局部放大等功能进行后处理，同时数字随机法对其中30例行普通X线摄影。由放射科经验丰富的医、技师各2名对所有鼻骨影像进行分析，评价其对鼻骨骨折、鼻骨整体及鼻周软组织的显示。结果100例DDR鼻骨影像中，诊断骨折46例，鼻骨整体及鼻周软组织显示满意的分别为95和92例；对照组30例DDR鼻骨影像发现骨折18例，X线片发现骨折11例，漏诊7例（x^2=5，14，P〈0，05），30例DDR影像中，鼻骨整体及鼻周软组织显示满意的均为28例；普通X线片两者显示满意的分别为6例（x^2=20．05，P〈0．05）和10例（x^2=15．06，P〈0．05）。结论DDR影像比普通X线影像能更好的显示鼻骨和鼻周软组织，提高鼻骨骨折的检出率。     

X线摄影中的疑难部位的摄影方法

我们对临床上常见的几个疑难摄影部位的解剖结构及其与周围组织的解剖关系进行分析，总结出了比较简便、实用的摄影经验，现介绍如下。     

床边CR摄影与传统床边摄影的对比研究

目的：评价计算机X线摄影术(CR)在床边照片的应用。方法：抽取我院CR床边按照影像和传统床过照片备1000例，由2位放射学医师及1位主管技师对影像进行分析，分别统计甲、乙、丙及废片率，同时也对条件进行分析评价。结果：(1)CR影像：甲级片率32．1％，乙级片率44.5％，丙级片率23．4％，废片率0％。(2)传统床造影像：甲级片率20．3％，乙级片率53．5％，丙片率16．8％，废片率9．4％。结论：CR床边照片质量明显比传统床边投照优秀，CR床边照片有利于放射诊断。     

如何提高摄影效率

X线摄影是放射科日常工作的重要组成部分。摄影技术的操作工序琐碎杂乱，在病人比较集中，急症患者较多时，尤显如此。如何提高摄影效率，使我们的工作趋向轻松便捷，值得技师们探讨，笔者从事X线摄影十年，对一些方法做了尝试，实践证明行之有效，在此与同道们交流。     

计算机X线摄影在颈椎常规摄影中的图像处理

计算机X线摄影（Computed Radiology，CR）是随着计算机的应用发展，到80年代才逐渐发展起来的计算机与传统X线相结合的成像系统。它的问世，使得传统的X线摄影发生了革命性的突破，图像的数字化存贮及远程传输成为现实。它的广泛应用，为提高影像诊断准确率及X线照片影像质量奠定了坚实的基础，本文以常规摄影中颈椎正侧位为代表对CR系统的图像后处理进行探讨。     

数字摄影与传统摄影在胸部正位的对比

我院自2004年1月起分别引进了AGFA计算机X线摄影（CR）系统及SIEMENS AXIOMAristos直接数字化成像X线摄影（DR）系统，根据两个系统投入使用2年的应用情况，在胸部摄影方面与传统摄影对比，其显著优点是改变了工作流程的方式，不仅在图像质量、照片的甲片率和对设备使用的工作效率得到大幅提高，而且患者检查所受辐射量也得到大幅降低。     

关于儿童摄影辐射防护

儿童是祖国的未来，是全社会关爱的热点，更是每个家庭关爱的重点，我国小儿人数在三亿以上，党和政府大力倡导少生优育，加强儿童保健事业至关重要。X线检查是一种具有利和有害两面性的检查手段，日常工作中，家长到放射科常问的活题“X线危害大不大？”“做哪种检查受辐射少”，这说明人们对其安全性的认识愈来愈高，     

Comparing image quality of flat-panel chest radiography with storage phosphor radiography and film-screen radiography

OBJECTIVE: To evaluate image quality of a large-area direct-readout flat-panel detector system in chest radiography, we conducted an observer preference study. A clinical comparative study was conducted of the flat-panel system versus the storage phosphor and standard film-screen systems. MATERIALS AND METHODS: Routine chest radiographs (posteroanterior) of 30 patients that were obtained using flat-panel, storage phosphor, and film screen systems were compared. The visibility of 10 anatomic regions and the overall image quality criteria were rated independently by three radiologists using a 5-point scale. The significance of the differences in diagnostic performance was tested with a Wilcoxon's signed rank test. Dose measurements for the three modalities were performed. RESULTS: The flat-panel radiography system showed an improved visibility in most anatomic structures when compared with a state-of-the-art conventional film-screen system and an equal visibility when compared with a storage phosphor system. The flat-panel system showed the greatest enhancement in the depiction of small detailed structures (p < 0.05) and achieved this with a reduction in overall radiation dose of more than 50%. CONCLUSION: The visibility of anatomic structures provided by this flat-panel detector system is as good as if not better than that provided by conventional or storage phosphor systems while emitting a reduced radiation dose.     

New computed radiography technologies in digital radiography

Digital radiography (DR) has become integral to modern diagnostic radiology. One of the earliest forms of DR, computed radiography (CR) using storage phosphors, has established itself as the mainstay of DR-based diagnostic imaging over the past 20 years. More recently, flat-panel DR systems based on solid state X-ray detectors with integrated, large-area, active-matrix readout electronics are promising further improvements in clinical workflow and image quality. Despite CR's longevity, innovations continue to be made. New developments in CR screen technologies, like structured (needle) screens, and new scanner concepts based on line-at-a-time reading promise major improvements in image quality (comparable to that of flat-panel systems), system through-put and physical size, at a cost comparable to that of today's systems. Thus, despite the advent of flat-panel acquisition systems, there will still be an important role for CR in the foreseeable future. After a brief review of the current state of CR technology, this paper will explore several of these new CR developments and present some examples of their potential clinical impact.     

Magnification radiography

Magnification radiography is the purposeful production of an image larger than the object being studied. This technique can be utilized to image detail that is not resolvable by normal means. An overview of magnification radiography, including the physics and equipment considerations, is presented to better acquaint the radiographer with this increasingly popular technique.     

Direct detector radiography versus dual reading computed radiography: feasibility of dose reduction in chest radiography

The image quality of dual-reading computed radiography and dose-reduced direct radiography of the chest was compared in a clinical setting. The study group consisted of 50 patients that underwent three posteroanterior chest radiographs within minutes, one image obtained with a dual read-out computed radiography system (CR; Fuji 5501) at regular dose and two images with a flat panel direct detector unit (DR; Diagnost, Philips). The DR images were obtained with the same and with 50% of the dose used for the CR images. Images were evaluated in a blinded side-by-side comparison. Eight radiologists ranked the visually perceivable difference in image quality using a three-point scale. Then, three radiologists scored the visibility of anatomic landmarks in low and high attenuation areas and image noise. Statistical analysis was based on Friedman tests and Wilcoxon rank sum tests at a significance level of P<0.05. DR was judged superior to CR for the delineation of structures in high attenuation areas of the mediastinum even when obtained with 50% less dose (P<0.001). The visibility of most pulmonary structures was judged equivalent with both techniques, regardless of acquisition dose and speed level. Scores for image noise were lower for DR compared with CR, with the exception of DR obtained at a reduced dose. Thus, in this clinical preference study, DR was equivalent or even superior to the most modern dual read-out CR, even when obtained with 50% dose. A further dose reduction does not appear to be feasible for DR without significant loss of image quality.