数字化曲面断层机的临床应用

目的评价数字化曲面断层机在口腔与颌面外科疾病诊断与治疗中的用途。方法 10128例口腔与颌面外科疾病患者均经TROPHY数字全景系统摄影检查,对摄影方法与曝光条件进行了总结分析,并与传统X线胶片进行比较。结果研究证实,数字化曲面断层机摄影具有图像质量高,层次清晰,对比度好,曝光条件低,速度快,辐射剂量低等优点,并显著优于传统X线胶片。结论数字化曲面断层机是以对比度与分辨率高以及成像质量好为明显特征,在口腔临床及科研、教学方面有宽阔的应用前景。     

CR在传统口腔曲面断层摄影中的探索和改进

目的：介绍传统口腔全景机获得数字化影像的一种简便和实用的方法,并探讨其应用的临床价值。方法：利用现有的岛津曲面断层机设备,自制盛装IP板的特制软皮套载体,在摄影时用它把IP板的软和IP板盒的硬进行互相转化,摄影完后用西门子数字成像处理系统对已摄影好的IP板进行扫描,再用Sony相机打印,从而得到口腔全景数字化影像。结果：改进技术后得到了高质量的数字化影像,随机搜集200例影像资料,进行质量评比和统计分析,其优片率达97%以上。结论：此技术可获得与其它CR一样优点众多的口腔曲面全景数字化影像,可与医院设备支持匹配,合理优化资源,且具有动态范围调节灵活、投资小、收效大等优点。     

CR系统IP板的使用与保养体会

计算机X线摄影（Computed Radiography，CR）是一种较先进的医学成像技术，它采用IP影像版（ImagrPlate，IP）代替传统X线摄影技术所使用的胶片增感屏。在整个CR系统中，IP板是成像系统的关键元件，是作为记录用的载体，其特点是可以重复使用，但不具备影像显示功能，且本身价格较贵，因此平时工作中需要注意的环节有。     

CR系统的保养与维护

CR设备经过10余年的发展之后现在已经基本普及,其成像方式是以成像板(imaging plate IP)代替X线胶片作为记录信息的载体。CR与传统的X线摄影相比有以下优点:(1)实现了传统X线摄影的数字化;(2)提高了图像的密度分辨力和显示能力;(3)能实施图像的后处理,增加了显示信息的功能;(4)     

CR的原理及应用

随着电子技术的发展，医学成像的理论和数字方式具有强大的技术进步，使X线摄影数字化得到了发展。传统的X线摄影是以胶片作为成像的介质，发展到计算机摄影（CR）、直接数字摄影（DR），是将X线拍摄的影像信患记录在影像板（image plate，IP）上，经读取装置读取，由计算机计算出一个数字化图像，复经数字模拟转换器转换，于荧屏上显示出灰阶图像。CR与DSA中所述的DR同属数字化成像，提高了图象的密度分辨力和显示能力，增加图像的后处理功能实现放射科网络化和无胶片化管理。     

优化组合CR系统自动曝光控制成像参数

目的:优化组合CR系统自动曝光控制成像参数.材料和方法:采用两种规格的成像(IP)板,用不同组合的成像参数对胸部拟人水模摄影,检测电离室密度补偿与曝光参数的变化.以所得成像数据和两种规格的IP板,对A、B、C三组患者(每组各180例),不同部位摄影,检测不同曝光剂量组合摄影的影像质量和影像的密度值.结果:A组以两种规格的IP板、125kV摄胸部,图像对比度差;病灶细微结构显示不清.以73～85kV摄胸部,其图像明显好于125kV;B组与C组的小规格IP板(20.5cm×25.6cm)优于大规格IP板的(35cm×35cm)图像质量;影像密度值均在0.8～1.30范围内.结论:CR系统不宜采用高kV摄影;应使用合适规格的成像板.     

CR摄影技术与传统X线摄影的应用与体会

随着医学影像技术的飞速发展，高新技术在医学领域的应用，数字X线检查技术的相继出现，传统的X线摄影技术已逐渐走向过去。近年来，医学影像数字化处理发展迅速，常规X线摄影中使用的胶片增感屏组合成像方式形成影像无法直接数字化，而CR系统的出现，其优点越来越多地优于传统X线摄影技术，传统X线摄影都是以普通的X线胶片为探测器，接受一次性曝光后，经暗室冲洗来完成影像，但所获得的图像始终是一种模拟信息，不能进行任何处理。CR系统实现了用成像板来接受X线下的模拟信息，然后经过模数转换来实现图像的数字化，从而是传统的X线摄影能够进入存贮系统进行处理和传输。总结分析如下.     

口腔曲面断层摄影质量控制的实验及应用研究

目的研究口腔曲面断层摄影质量控制的实验方法及应用。方法(1)用直尺钢珠对比实验对比直射线区与斜射线区成像效果的差异,分析牙齿以上区域模糊的形成原因;(2)用直尺钢珠实验模拟切牙进行不同倾斜角度曲面断层摄影,检测切牙倾角对曲面断层摄影图像清晰度的影响;(3)用铜丝网试验多点测量计算绘制出曲面断层摄影之图像层面结构图。结果(1)斜射线并不会导致影像变形模糊,牙齿以上区域图像模糊并非斜射线之故;(2)直尺上钢珠的清晰度与直尺的倾斜角度有关,倾角过大即可产生模糊,提示切牙根部模糊与切牙倾斜程度有关;(3)曲面断层摄影各区域图像层面厚度不同,切牙区厚度最薄,仅0.7 cm,使多数人切牙全长不能同时落在图像层面内而产生模糊。结论通过不同方法可以改善口腔曲面断层摄影的质量。     

不同使用期计算机摄影成像板成像参数比较

计算机摄影成像板(Computed radiography imaging plate，CRIP)，是成像的关键部件，它由含有微量二价铕的氟氯化钡晶体构成，x线光子能量以潜影形式存储在IP中，成为模拟信息的载体，其作用与胶片相似。经激光扫描，IP将存储能量以荧光形式释放出来，其强度与吸收的x线光子能量成正比。荧光信号再转换为电信号，经计算机处理获得x线衰     

直接数字摄影系统的质量控制与质量保证

直接数字摄影系统由影像探测器(成像板)、控制器、工作站、X线机和激光像机等组成，质量控制的内容也贯穿于整个成像链的全过程。X线机的摄影参数，控制台上原始图像的确定，工作站图像的后处理与调整，激光像机的密度与对比度和特性曲线的调节，胶片特性与药液显影效力和新旧药液等都必须全方位协调控制，才能保证最佳的图像质量(位置正确、剂量合适、细节清楚、取景美观)。     

数字X线照片影像质量相关因素初步分析

目的：探讨影响数字X线照片影像质量的相关因素，提高数字X线照片影像质量。方法：通过分析计算机X线摄影(CR)与直接数字X线摄影(DR)所产生的数字X线照片影像质量相关因素：曝光量与自动曝光控制(AEC)的使用；DR、CR主机(扫描仪)及图像读取工作站；影像板(IP)因素；图像后处理工作站功能；激光打印机等。针对数字X线照片成像的各个环节加以控制。结果：获得优质数字X线照片影像必需做到：选择合适的曝光条件并合理使用AEC；掌握DR主机、CR扫描仪及图像读取工作站的性能特点；保证IP质量及定期清洗保养IP；充分了解并利用好图像后处理工作站的功能；正确设置配套激光打印机参数。结论：了解影响数字X线照片影像影像质量的相关因素，充分发挥数字X线照片影像图像的后处理优势，可以明显提高数字X线照片影像图像的质控水平。     

Reusable imaging plate (IP) for swift and automatic measurement of X-ray CT dose profiles

PURPOSE: In multi-slice CT, over beaming by penumbra effect has been reported, and measurements of X-ray CT beam profiles are very important for accurate performance assessment. This study was conducted in order to facilitate and economize on the measurement of CT dose profiles. METHODS: The imaging plate (IP: HR-V type, Fuji) was placed in its case, X-rayed, and then read with a digital IP reader, which then erased the data in preparation for reuse. The values were then compared with the values obtained with the standard one-use imaging film. The CT scanner used was a Toshiba Aquilion Multi (4 rows). RESULTS: The shape of the beam profile obtained using the IP method was for all practical purposes identical to that obtained using the film method. The FWHM values for 2.0, 4.0, 8.0, 12.0, 16.0, 20.0 and 32-mm beam were 4.88, 6.61, 10.2, 14.9, 18.2, 22.4 and 35.0 mm for the IP method and 4.81, 6.66, 10.2, 14.7, 18.1, 22.3 and 34.8 mm for the film method. In addition, in the IP method, the results obtained for the shape of the beam profile and the FWHM were found to be extremely similar irrespective of the X-ray tube used or individual differences between IPs. CONCLUSION: We have developed a new X-ray CT beam profile measurement system using an IP. This IP method permits data processing to be performed entirely in the digital domain, allowing high-precision measurements to be obtained with ease.     

Computed radiography: photostimulable phosphor image plate technology

Computed radiography is emerging as a digital imaging modality for use in conventional radiography. It is based on photostimulable phosphor image plate technology. The image plate (IP) is housed in a cassette similar to a standard radiographic cassette. The IP phosphor retains a latent image of the energy pattern to which it was exposed. This latent image is "read" as it is released from the phosphor by laser light exposure. The image is laser printed on 10 in x 14 in film.     

Review of optical storage technology for archiving digital medical images

Digital optical recording (DOR) is a data-acquisition and storage technology important to the development of picture archiving and communication systems (PACS). DOR offers attractive advantages in high-density, low-cost archival storage of images and other information. At present, film is used as the storage medium for archiving images generated by both conventional equipment and digital technologies such as computed tomography, digital subtraction angiography, magnetic resonance imaging, and nuclear medicine. The basic methods of DOR data storage are discussed together with requirements essential for making DOR an acceptable alternative to film archiving. The impact of DOR technology on the operation of an imaging department is projected.     

应用图像浏览软件构建简易医学影像存档与通讯系统的研究

目的论证利用数字影像与通信标准（Digital Imaging and Communications in Medicine,DICOM）图像浏览软件构建简易医学影像存档与通讯系统（picture archiving and communication systems,PACS）,实现医学影像全院性共享及远程会诊的方法及其可行性。方法利用医院现有的局域网、各个科室现有PC机,采用互联网上免费DICOM图像浏览软件,通过网络及软件设置,将具有DICOM接口并开放的影像设备（如CR、DR、CT、MRI、DSA、数字胃肠及具有网络接口的激光胶片相机等）与PC机连接。结果具有DICOM图像浏览软件的PC机实现实时传输、调阅影像图像,达到类PACS效果。同时可以利用互联网,实现远程会诊。结论利用DICOM图像浏览软件构建简易PACS系统方法简单、经济、实用,特别适合在各中小型医院。     

Comparison of two imaging modalities: F-speed film and digital images for detection of osseous defects in patients with interdental vertical bone defects

OBJECTIVES: The aim of the present study was to compare the diagnostic accuracy of F-speed conventional film, unenhanced digital images and inversion-enhanced digital images for the detection of osseous defects in patients with vertical bone defects. METHODS: 23 vertical osseous defects in the mandible were evaluated. Intrasurgical measurements were made from the cementoenamel junction (CEJ) to the deepest extension of the osseous defects by one of the researchers. Radiographic measurements were obtained on conventional F-speed film, unenhanced digital images and inversion-enhanced digital images by six examiners. From each measure the corresponding probe measure was subtracted to form a difference score. RESULTS: Significant differences in means of difference scores were found among examiners within each imaging modality, and among the modalities within five of the six examiners. A significant (P<0.001) interaction term for the ANOVA indicated that differences among modality means were not the same across all examiners. The difference means were significantly different from zero for five of the six examiners with conventional F-speed film, four of six with inversion enhanced digital images, but for only one of six for unenhanced digital images. The reliability coefficient computed on a per examiner basis was 0.90 for conventional F-speed film, 0.94 for unenhanced digital image and 0.79 for inversion-enhanced digital image. CONCLUSIONS: In this study, unenhanced digital imaging was found to be superior to conventional F-speed film and inversion-enhanced digital images for accurately imaging periodontal osseous defects in patients.     

Evaluation of a new digital panoramic system: a comparison with film

OBJECTIVES: To evaluate the diagnostic efficacy of the Orthophos DS digital panoramic system (Sirona, Bensheim, Germany) for the detection of dento-alveolar disease in comparison with film. METHODS: Five patients selected for admission to the School of Dentistry had a panoramic radiograph obtained with the Orthophos Plus (Sirona, Bensheim, Germany) system, a digital panoramic image obtained with the Orthophos DS (Sirona, Bensheim, Germany) system and a full mouth series. The ground truth was determined from the full mouth series by a panel of board certified oral and maxillofacial radiologists using the Delphi method. Four observers scored both the film and digital panoramic images for the presence of caries and marginal periodontitis. Results were statistically analysed using ROC analysis and ANOVA. RESULTS: There was no significant difference (P=0.704) between the two modalities for the detection of caries but there was a significant difference (P=0.015) for the detection of periodontal disease where conventional panoramic film performed better than the digital image. CONCLUSIONS: Though the conventional film was better than the digital image for the detection of periodontal disease, further studies are needed to determine the clinical significance of this result in relation to the potential advantages of digital technology.     

Financing a large-scale picture archival and communication system

RATIONALE AND OBJECTIVES: An attempt to finance a large-scale multi-hospital picture archival and communication system (PACS) solely based on cost savings from current film operations is reported. MATERIALS AND METHODS: A modified Request for Proposal described the technical requirements, PACS architecture, and performance targets. The Request for Proposal was complemented by a set of desired financial goals-the main one being the ability to use film savings to pay for the implementation and operation of the PACS. RESULTS: Financing of the enterprise-wide PACS was completed through an operating lease agreement including all PACS equipment, implementation, service, and support for an 8-year term, much like a complete outsourcing. Equipment refreshes, both hardware and software, are included. Our agreement also linked the management of the digital imaging operation (PACS) and the traditional film printing, shifting the operational risks of continued printing and costs related to implementation delays to the PACS vendor. An additional optimization step provided the elimination of the negative film budget variances in the beginning of the project when PACS costs tend to be higher than film and film-related expenses. CONCLUSION: An enterprise-wide PACS has been adopted to achieve clinical workflow improvements and cost savings. PACS financing was solely based on film savings, which included the entire digital solution (PACS) and any residual film printing. These goals were achieved with simultaneous elimination of any over-budget scenarios providing a non-negative cash flow in each year of an 8-year term.     

Noise properties in the fading of the imaging plate on a computed radiography system

Fading of the imaging plate (IP) in computed radiography (CR) systems with photostimulable phosphors is known well. The relation between noise properties and the fading of the IP in a CR system was investigated. Uniform exposure for the IP with various times between exposure and readout for the same exposure was used for this study. The relative intensity of photostimulated emission and the digital Wiener spectra were calculated. The relative intensity of photostimulated emission decreased with increasing time, whereas Wiener spectral values showed no difference with increasing time. We concluded that noise properties were not affected by the fading of the IP in the CR system.