用影像存档与通讯系统进行影像融合

目的 应用影像存档与通讯系统（PACS）和影像融合软件进行不同显像形式图像融合的方法学探索。方法 图像的原始采集和处理分别使用Siemens螺旋CT、MR和E．CAM^ 双探头带符合线路SPECT仪。经CT、MR和核医学等科室间的PACS图像查询、传输和存取，用安装在SPECT仪计算机上的Medical image merge (MIM)软件进行影像融合处理。原始影像容积数据用重新分层方法创建图像，通过平移和旋转相关的观察端面、调节影像对比度和透明度等实现融合影像。结果 通过PACS成功地进行了CT、MR和核医学影像的传输、存取和载入，进行MR与核医学脑显像、CT和核医学胸部显像等的图像融合，获得了理想的图像。结论 应用PACS和MIM软件进行影像融合能获取良好的图像。     

Effect on image data resampling in evaluation of the basic imaging properties for a digital radiographic system based on a flat panel detector

We investigated the effect on image data resampling in an evaluation of the basic imaging properties for a digital radiographic system based on a flat panel detector (FPD). One of the latest digital radiographic systems was used in this study. This system was based on a direct-conversion FPD of amorphous selenium. The basic imaging properties of the system were evaluated by measuring characteristic curve, presampled modulation transfer function (MTF), and Wiener spectrum (WS) using DICOM image with a matrix size of 2048 x 2048. The evaluations were performed under two conditions because matrix size automatically changes according to the selection of imaging size. One of the conditions was a different matrix size between image data acquired on the FPD and the output image (DICOM image for which resampling was performed). The other condition was that these matrices be the same size (DICOM image with no resampling performed). Resampling did not affect the characteristic curves. However, MTF and the WS obtained from the resampled data were different from those of the one not resampled, which is considered to be the "inherent" basic imaging properties, and this phenomenon was remarkable, especially in terms of the MTFs. Our study indicates that the effect on resampling should not be disregarded in evaluating the basic imaging properties of digital radiographic systems. Therefore, it is mandatory to use DICOM images for which no resampling was performed in order to evaluate the inherent basic imaging properties for digital radiographic systems.     

Construction of DICOM-WWW gateway by open source, and application to PDAs using the high-speed mobile communications network

The author constructed a medical image network system using open source software that took security into consideration. This system was enabled for search and browse with a WWW browser, and images were stored in a DICOM server. In order to realize this function, software was developed to fill in the gap between the DICOM protocol and HTTP using PHP language. The transmission speed was evaluated by the difference in protocols between DICOM and HTTP. Furthermore, an attempt was made to evaluate the convenience of medical image access with a personal information terminal via the Internet through the high-speed mobile communication terminal. Results suggested the feasibility of remote diagnosis and application to emergency care.     

Computational replicas: anatomic reconstructions of cerebral vessels as volume numerical grids at three-dimensional angiography

BACKGROUND AND PURPOSE: We present a relatively simple approach that physicians can use to reconstruct cerebral vessels as 3D numerical grids or computational replicas. The method accurately duplicates their geometry to provide computer simulations of their blood flow. METHODS: Initial images were obtained by using any medical imaging technique, such as MR angiography, CT angiography, or 3D digital subtraction angiography. The data were collected in DICOM format and converted by a DICOM reader into a 3D gray-scale raster image. The image was then processed by using commercial visualization and mesh generation software, which allowed extraction of the luminal surface of the blood vessel (by using the isosurfacing technique). The subsequent final output was an unstructured tetrahedral grid that can be directly used for detailed analysis of cerebral vascular geometry for patient-specific simulations of blood flow. RESULTS: Four examples of grid reconstruction and blood flow simulation for patients with ruptured aneurysms were validated with angiographic and operative findings. The ruptured areas were correlated with areas of high fluid-induced wall-shear stress. CONCLUSION: This approach promises to be a practical tool for planning treatment and follow-up of patients after neurosurgical or endovascular interventions with 3D angiography. The proposed commercial packages or conceptually similar ones seem to be relatively simple and suitable for direct use by neurosurgeons or neuroradiologists.     

Hanging protocol and viewers for a dental full picture [corrected] archiving and communication system (PACS) [corrected

OBJECTIVES: Study objectives were: to develop a hanging protocol for displaying digital transmission radiographic images of oral and maxillofacial regions using a dental DICOM (digital imaging and communication in medicine) viewer and a dental Web viewer; and to give information on a system that allows patients and health professionals to share image information. METHODS: For the hanging protocol, alphanumeric tags were defined and used in a DICOM modality worklist. These tags consisted of layout information to display images on monitors by the type of projection method and assignment information to display images of template for intraoral full-mouth survey that were numbered and slotted according to tooth position. Tooth code and algorithm for assignment of images for intraoral full-mouth survey were determined. Expanded correspondence for viewers was used for modalities without tags. Images could be edited by quality control system. An electronic medical record (EMR) system, a radiological information system (RIS) and a picture archiving and communication system (PACS) with servers, terminals and viewers were set up in a patient-centred hospital environment. RESULTS: Using the hanging protocol, the viewers displayed digital transmission radiographic images automatically on display areas on one or multiple monitors showing intraoral, panoramic and extraoral views produced during various examinations. The images were also displayed using the coupling function of EMR and RIS. Users can compare the images taken at various times more efficiently. CONCLUSION: The new system using a dental DICOM viewer and a dental Web viewer is the most advanced for examining oral and maxillofacial regions compared with medical viewers. Our local but clinically operational hanging protocol should be a good model for DICOM Working Group 22.     

Voxel-based mouse and rat models for internal dose calculations.

The ability to estimate absorbed doses in experimental animals to which radiolabeled material has been administered may be important in explaining and controlling potential radiation toxicity observed during preclinical trials. Most previously reported models for establishing doses to small animals have been stylized and mathematically based. This study establishes dose factors for internal sources in realistic models of a typical mouse and a typical rat, based on image data obtained using a dedicated small-animal CT scanner. METHODS: A transgenic mouse (body mass, 27 g) and a Sprague-Dawley rat (body mass, 248 g) were imaged using the dedicated small-animal CT scanner. Identified organs were segmented using computer tools that Vanderbilt University applies to process human images for 3-dimensional dosimetry. Monte Carlo N-particle transport code (MCNP) input files were prepared from the 3-dimensional, voxel-based image data. Using methods established for human studies, radiation transport calculations of absorbed fractions (AFs) were performed using MCNP, version 4C, on the segmented images, and dose conversion factors for several radionuclides were developed. RESULTS: AFs were established at discrete energies for electron and photon sources assumed to be uniformly distributed throughout approximately 10 source and target regions in both models. Electron self-irradiation AFs were significantly less than 1.0 for many organs, at energies above 0.5 MeV, and significant cross irradiation was observed for high-energy electrons, such as those from (90)Y or (188)Re, in many organs. Calculated dose conversion factors reflected these trends and agreed well with the results of other authors who have undertaken similar investigations. CONCLUSION: The AFs calculated in this study will be useful in determining the dose to organs for mice and rats similar in size to those studied here. The segmented, voxel-based models developed here can be used for external dose calculations as well.     

企业级医疗影像信息集成平台研究

目的:探讨大型医院内部各影像系统信息共享和医疗资源整合方法.方法:采用IHE技术框架为理论指导,结合国内医院实际提出"企业级医疗影像信息集成平台"及其开放整合方案,通过各厂商的密切配合、实施,初步实现对全院DICOM影像的统一归档和统一发布.结果:经过实践验证,集成平台切实有效,既提高临床医生对医学影像信息的使用效率,提高诊疗质量,又便于医信技术人员对影像信息的集成管理.结论:基于IHE技术框架的企业级影像信息集成平台研究被证明是可行、可靠和有效的.     

Defining a new annotation object for DICOM image: a practical approach.

In this article, we present a new way of creating annotation objects for DICOM images, using the redundant data channel. Various types of annotations, including types containing color information, are possible and annotation objects can overlap the original DICOM image on a screen. Annotation objects can be created easily using a digital pen. Scanned images used in an electronic patient record can be added to objects. Although there are various ways of manipulating annotation objects, such as insertion, addition and modification of annotation objects in the DICOM image, the original clinical image is not affected because a redundant data channel is used for the annotation. The proposed method is expected to be very useful to medium and small clinics that cannot afford picture archiving and communication systems, as the DICOM standard makes provision for the annotation of clinical images in various ways.     

Design and development of a secure DICOM-Network Attached Server

It is not easy to connect a Web-based server with an existing DICOM server, and using a Web-based server on the Internet has risks. In this study, we designed and developed a secure DICOM-Network Attached Server (DICOM-NAS) through which the DICOM server in a hospital LAN was connected to the Internet. After receiving a client's image export request, the DICOM-NAS sent it to the DICOM server using the DICOM protocol. The server then provided DICOM images to the DICOM-NAS, which transferred them to the client, using HTTP. The DICOM-NAS plays an important role between the DICOM protocol and HTTP, and stores the requested images only temporarily. The DICOM server keeps all of the original DICOM images. If an unauthorized user attempts to access the DICOM-NAS, medical images cannot be accessed because images are not stored in the DICOM-NAS. Furthermore, the DICOM-NAS has features related to reporting and MPR. Therefore, the DICOM-NAS does not require a large storage capacity, but can greatly improve information security.     

PACS and Web-based image distribution and display.

Picture archiving and communication system (PACS) delivers images to the display workstations mostly through digital image communication in medicine (DICOM) protocols in radiology departments, and there are lots of medical applications in healthcare community needing to access PACS images for different application purposes. In this paper, we first reviewed a hospital-integrated PACS image data flow and typical diagnostic display software architecture, and discussed some Web technologies and Web-based image application server architectures, as well as image accessing and viewing methods in these architectures. Then, we present one approach to develop component-based image display architecture and use image processing and display component to build a diagnostic display workstation, and also, give a method to integrate this component into Web-based image distribution server to enable users using Web browsers to access, view and manipulate PACS DICOM images as easy as with PACS display workstations. Finally, we test and evaluate the performance of image loading and displaying by using the diagnostic display workstation and the component-based Web display system, the experimental results show that the image distribution and display performance from the Web server to browser clients is similar with that of the image loading and displaying procedure of the diagnostic workstation as more browser clients accessing the Web server at same time. We also discuss the advantages and disadvantages of the Web-based image distribution and display in different medical applications.     

A visual displayer for publishing radiologic images on the World Wide Web

PURPOSE: To present a software suitable for publication of medical images on the World Wide Web and compatible with both the DICOM and other popular formats like GIF and JPEG. MATERIALS AND METHODS: DICOM viewer is a Java applet, written in Java 1.0. The tool offers the capability to publish medical images, to modify brightness and contrast (windowing) and to magnify the picture (magnification lens). Information related to the image is available for consultation only for DICOM images. RESULTS: The viewer was tested with many DICOM files, generated by our PACS or downloaded from Internet. It works well with the DICOM 3.0 file format, but correct functioning is not granted for previous releases. The software was compatible with all the most popular Web browsers (MS Internet Explorer 3.0 or newer, Netscape Navigator 4.5 or newer, Sun and HotJava) and it works well in Windows, Sun Solaris. Macintosh, Windows CE. A 512 kb image (a standard MR image) requires about 5 seconds to be shown on an Intel Pentium II PC with 32 Mbyte RAM connected on a 10 Mbit/s Ethernet network. About 3 seconds are needed to download the file and about 2 seconds to display the image. Windowing and zooming are quick enough. CONCLUSIONS: The applet allows to publish DICOM medical images directly on the World Wide Web, without converting them into another graphical format. Moreover, it supplies some image processing tools common in the radiological environment. The viewer characteristics make it suitable for preparing teaching radiology sites or clinical files on the Web. The viewer's performance is somewhat poor, particularly on the Internet. Better performances are achieved on local area network (intranet). To improve performance, we will introduce file compression and rewrite the software in Java 1.1. The software is available from the author free of charge.     

Investigation of the accurate measurement of the basic imaging properties for the digital radiographic system based on flat panel detector

PURPOSE/AIM OF THE EXHIBIT: The purpose of this exhibit is: 1. To explain "resampling", an image data processing, performed by the digital radiographic system based on flat panel detector (FPD). 2. To show the influence of "resampling" on the basic imaging properties. 3. To present accurate measurement methods of the basic imaging properties of the FPD system. CONTENT ORGANIZATION: 1. The relationship between the matrix sizes of the output image and the image data acquired on FPD that automatically changes depending on a selected image size (FOV). 2. The explanation of the image data processing of "resampling". 3. The evaluation results of the basic imaging properties of the FPD system using two types of DICOM image to which "resampling" was performed: characteristic curves, presampled MTFs, noise power spectra, detective quantum efficiencies. CONCLUSION/SUMMARY: The major points of the exhibit are as follows: 1. The influence of "resampling" should not be disregarded in the evaluation of the basic imaging properties of the flat panel detector system. 2. It is necessary for the basic imaging properties to be measured by using DICOM image to which no "resampling" is performed.     

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。     

PACS图像显示器质量控制的初步研究

目的探讨放射科PACS系统中图像显示器的质量保证(QA)、质量控制(QC)问题。方法参考美国医学物理学会第18工作组(AAPMTG18)制定的测试图和质量评估标准,利用光度计、显示器校正软件,对3种型号的BARCOCRT灰阶显示器进行季度性定量检测。内容包括:DICOM灰阶标准显示函数校正、最高亮度和最低亮度检测、亮度均一性检测、显示器分辨率、几何失真校正。结果显示器的各项性能指标都符合AAPMTG18规范。放射科95%的医学图像依靠PACS显示器做出了诊断。结论PACS图像显示器的质量控制是确保数字化医疗环境优质性的重要措施。     

Operating data and unsolved problems of the DICOM modality worklist: an indispensable tool in an electronic archiving environment

PURPOSE: We evaluated the efficacy of DICOM worklist software for radiological modalities from the viewpoint of risk management, to reduce mislabeled image data in an electronic archiving environment. We focused on the following five points: 1) the effectiveness of the DICOM modality worklist, 2) problems involving incorrect patient and image data, 3) the presence of incorrect profiles despite the transfer of patient profiles online via the DICOM worklist, 4) ways to eliminate entry failure, and 5) further examination even if data entry were correct. MATERIALS AND METHODS: Retrospective data of patient profiles with image data were evaluated both before and after installation of DICOM modality worklist management software at Sakai Municipal Hospital. All radiology modalities were connected to RIS terminals in which DICOM modality worklist software was installed. Patient profiles were transferred online from RIS terminals to the modalities. It was not necessary for technologists to type patient profiles in usual examinations. RESULTS: Before installing the DICOM modality worklist software, the number of data entry errors was 31 and the rate was 6.4% of 487 examinations. After installation, manual data entry occurred in 80 of 1,994 examinations. The number of data entry errors for patient profiles was two, and the rate was 0.1% of the total examinations (p < 0.0001). Before installing the DICOM modality worklist, two wrong patient IDs that corresponded to other existing patient IDs were typed into the modality. No patient IDs were mixed up after installation of the DICOM modality worklist (p = 0.0385). CONCLUSION: The DICOM worklist was indispensable to electronic archiving because it decreased incorrect patient profiles that corresponded to image data loss. This was effective in decreasing patient mix-ups that could lead to serious malpractice. Despite the DICOM worklist, however, some incorrect patient profiles remained as a result of manual typing errors. The reasons for manual typing included emergency examinations, paper-based operations, and system shutdown. Furthermore, the risk of patient mix-ups remained even if the patient profile was correct. To eliminate or decrease medical accidents, determining why accidents happen and ensuring better data confirmation are necessary.     

Utilizing data grid architecture for the backup and recovery of clinical image data.

Grid Computing represents the latest and most exciting technology to evolve from the familiar realm of parallel, peer-to-peer and client-server models. However, there has been limited investigation into the impact of this emerging technology in medical imaging and informatics. In particular, PACS technology, an established clinical image repository system, while having matured significantly during the past ten years, still remains weak in the area of clinical image data backup. Current solutions are expensive or time consuming and the technology is far from foolproof. Many large-scale PACS archive systems still encounter downtime for hours or days, which has the critical effect of crippling daily clinical operations. In this paper, a review of current backup solutions will be presented along with a brief introduction to grid technology. Finally, research and development utilizing the grid architecture for the recovery of clinical image data, in particular, PACS image data, will be presented. The focus of this paper is centered on applying a grid computing architecture to a DICOM environment since DICOM has become the standard for clinical image data and PACS utilizes this standard. A federation of PACS can be created allowing a failed PACS archive to recover its image data from others in the federation in a seamless fashion. The design reflects the five-layer architecture of grid computing: Fabric, Resource, Connectivity, Collective, and Application Layers. The testbed Data Grid is composed of one research laboratory and two clinical sites. The Globus 3.0 Toolkit (Co-developed by the Argonne National Laboratory and Information Sciences Institute, USC) for developing the core and user level middleware is utilized to achieve grid connectivity. The successful implementation and evaluation of utilizing data grid architecture for clinical PACS data backup and recovery will provide an understanding of the methodology for using Data Grid in clinical image data backup for PACS, as well as establishment of benchmarks for performance from future grid technology improvements. In addition, the testbed can serve as a road map for expanded research into large enterprise and federation level data grids to guarantee CA (Continuous Availability, 99.999% up time) in a variety of medical data archiving, retrieval, and distribution scenarios.     

Development of a low-cost DICOM-server for teaching and research purposes

PURPOSE: This paper describes our experience in developing a DICOM (Digital Imaging and Communications in Medicine) server based on widely available personal computers enabling to use X-ray digital images for teaching and scientific purposes. MATERIALS AND METHODS: The system is based on a DICOM server running on a widely used personal computer. The selected DICOM images are collected directly from the radiological equipment or from a dedicated 3D image processing workstation through a LAN connection and converted into one of the standard formats (JPEG or GIF) to allow their direct importing into multimedia presentations for teaching or scientific purposes. RESULTS: This system allows fast and easy collection of radiological images in DICOM format directly from the diagnostic equipment or from the graphical workstation. These images may be used for scientific and teaching presentations without loss of image quality and colour characteristics in 3D images as there is no off-line acquisition process. CONCLUSIONS: The extensive possibilities of implement the system described on widely used PCs makes the system extremely versatile and facilitates the preparation of teaching material and scientific publications.     

WINDOWS环境下DICOM医学图像显示方法的初步研究

目的：探讨WINDOWS环境下显示DICOM格式图像的方法.方法：通过自编程序读出DICOM图像的相关数据,实现DICOM格式图像在WINDOWS下的显示.结果：选取MR、CT、DR等不同模态的DICOM图像进行实验,均可正确显示.结论：针对DICOM图像文件存储的格式编制的程序,实现了DICOM图像文件的读取显示.本程序运行于WINDOWS环境,不依赖于具体的DICOM工作站,便于科研教学使用.     

Einsatzmöglichkeiten eines offenen magnetresonanztomographen in der therapiesimulation und dreidimensionalen bestrahlungsplanung

PURPOSE: A system for digital integration of an open MR scanner (0.23 T, Figure 1) in therapy simulation and 3D radiation treatment planning is described. METHOD: MR images were acquired using the body coil and various positioning and immobilization aids. A gradient echo sequence (TR/TE 320 ms/24 ms) was used to create axial and coronal data sets. Image distortions were measured and corrected using phantom measurements (Figure 2) and specially developed software. RESULTS: Maximal and mean distortions of the MR images could be reduced from 19 mm to 8.2 mm and from 2.7 mm to 0.7 mm, respectively (Figure 3 to 5, Table 1). Coronal MR images were recalculated in fan beam projection for use at the therapy simulator. Tumor and organ contours were transferred from the MR image to the digitally acquired and corrected simulator image using a landmark matching algorithm (Figure 6 and 7). For 3D treatment planning, image fusion of axial MR images with standard CT planning images was performed using a landmark matching algorithm, as well (Figure 8). Representative cases are shown to demonstrate potential applications of the system. CONCLUSION: The described system enables the integration of the imaging information from an open MR system in therapy simulation and 3D treatment planning. The low-field MR scanner is an attractive adjunct for the radio-oncologist because of the open design and the low costs.