Systems integration for PACS

A successful PACS (Picture Archiving and Communications System) implementation requires an eclectic integration of a number of key technologies. Among these are equipment interfaces, communications, storage, and display. Coincident with this, the software architecture must support a distributed system of heterogeneous structures, provide for protocol and format conversions to a unified system standard, be scalable to accommodate expansion, and provide a measure of fault tolerance. In this paper we survey the current state of the UCLA PACS components and architecture.     

PACS服务器架构在应急处理方案中的应用价值

目的探讨PACS服务器架构模式在应急处理方案中的应用价值。方法针对我院影像设备多及数据流量大的特点,PACS服务器设计采用分级体系管理架构。信息中心设立企业级服务器2台,1台为中心服务器,1台作为后备服务器,完成所有影像及病人资料接收、存储、调度及分发等服务,影像科及临床科分别设置2台(可扩充)影像前置服务器及1台临床前置服务器(可扩充),解决大并发访问对主服务器的压力及多个服务器之间的相互热备;开发提供一套科研教学前置服务器,用于教学及科研资料的存储及调阅。结果服务器分级体系架构在PACS遇到故障或灾难时,如中心服务器单点故障、中心服务器整体系统不可用或某个前置服务器系统不可用3种情况下,均能进行相应的应急处理,确保整个PACS系统正常运行。结论采用服务器分级架构体系强调多个服务器之间的相互热备,对于保障发生灾难性故障时整个系统的安全性具有重大的意义。     

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.     

Automatic acquisition interfaces for computed radiography, CT, MR, US, and laser scanner

Existing radiological imaging devices such as computed radiography (CR), computed tomography (CT), magnetic resonance imaging (MR), and ultrasound (US) systems generally do not have a direct digital interface to an external computer. Thus, special developments are necessary for their integration into a Picture Archiving and Communication System (PACS). The interface architecture and software models for performing automatic data acquisition from these devices as well as a CR plate scanner and a laser film digitizer are discussed based on their networking capabilities and the accessibility of internal data structures. The design approaches and operation efficiencies vary drastically depending on whether additional modules are needed, and whether the acquisition is performed on-line or off-line. In addition to the image data link, a complete acquisition interface includes polling of text patient information, image reformatting to the UCLA standard, and communication to the archival database.     

基于DICOM标准和分布式对象技术的PACS体系研究

目的 改变传统PACS的2层C/S体系结构.方法 在深入研究PACS体系结构的基础上,结合DICOM标准和分布式对象技术,将基于分布式对象技术的3层客户/服务器体系结构应用到PACS中,设计3层分布式PACS体系结构.结果 分布式PACS相对于基于DICOM网络的传统PACS在系统结构和性能上有较大改进,较大地提高了PACS系统的开放性和互联互操作性.结论 新的体系结构不仅提高了PACS整个系统的执行性能,还满足了PACS今后发展中提出的较高的互联互操作性和开放性的要求.     

An economical, personal computer-based picture archiving and communication system.

Taichung Veterans General Hospital has been developing a hospital-wide picture archiving and communication system (PACS) since 1993. A personal computer-based environment was implemented to reduce costs (only $2,500 for each view station) and take advantage of distributed system techniques. Other features of the PACS are automatic image acquisition, hierarchic storage management, efficient image transmission, robust fault tolerance, and user-friendly image manipulation. The system is integrated with the hospital information system so that Chinese-language patient data can be automatically transferred. A four-tier storage hierarchy and a multipath search strategy are used to improve reliability and efficiency. Image compression and efficient image transmission techniques (autorouting and prefetching) are used to reduce the response time. Robust fault tolerance is achieved with fault-tolerant hardware, image replication, and a system watchdog. User-friendly image manipulation features include easy adjustment of the brightness, contrast, or quality of the displayed image; several windows for image display; and image measurement capability. The PACS currently supports computed tomography, ultrasound, magnetic resonance imaging, computed radiography, and digital fluoroscopy; almost all appropriate personal computers in the hospital can be used as view stations. Users are satisfied with the quality, reliability, and performance of the system.     

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.     

In-house access to PACS images and related data through World Wide Web

The development of a hospital wide PACS is in progress at the University Hospital of Geneva and several archive modules are operational since 1992. This PACS is intended for wide distribution of images to clinical wards. As the PACS project and the number of archived images grow rapidly in the hospital, it was necessary to provide an easy, more widely accessible and convenient access to the PACS database for the clinicians in the different wards and clinical units of the hospital. An innovative solution has been developed using tools such as Netscape navigator and NCSA World Wide Web server as an alternative to conventional database query and retrieval software. These tools present the advantages of providing a user interface which is the same, independent of the platform being used (e.g. Mac, Windows, UNIX), and an easy integration of different types of documents (e.g. text, images). A strict access control has been added to this interface. It allows user identification and access rights checking, as defined by the in-house hospital information system, before allowing the navigation through patient data records.     

Integration of PACS and HIS into the workflow of a nuclear medicine department. Experience in Regensburg

AIM: The development of new diagnostic techniques and the implementation of a modern quality control management system requires the continuous adaptation of existing data processing tools to the nuclear medicine diagnostic workflow. Furthermore, PACS connected to HIS facilitates and enhances the transfer of data and pictures, and satisfies the legal requirements for data retention as regulated by law. Therefore, the aim of this work is to present the architecture, structure and results of such a system newly installed in a department of nuclear medicine. METHODS: Initially, the nuclear medicine workflow was carefully analyzed and each step was correlated to the corresponding module. The standard SAP R/3 and IS-H/IS-H(*)med based software used for patient administration at the University of Regensburg Hospital was adapted to the needs of the Nuclear Medicine Department. The networking of the imaging systems was done by integration of a PACS. Finally, the PACS was connected to the HIS to allow the attachment of images to the medical report. RESULTS, CONCLUSION: By connecting the HIS to the nuclear medicine PACS, the workflow was significantly improved. The data management sequence starting at the reception desk, continuing through the nuclear medical examination, to the physician's final written and image report is clearly structured. Although high demands exist on technical support and administration the integration of PACS and HIS into the nuclear medicine workflow leads to enhanced efficiency and reduction in hospital costs. Patient and data management are considerably improved in this way.     

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.     

PACS database architecture and design

PACS (Picture Archiving and Communication Systems) database design requires careful understanding of the data and processing needs of radiologists, referring physicians, radiology staff, administrators, and researchers. Due to access requirements, the physical implementation for the management of small text data sets differs from the implementation strategy for large image data sets (centralized vs. distributed storage strategies). In this paper we discuss the database structure, storage architecture, file placement strategies, and administration considerations of the UCLA PACS.     

Picture archiving and communication system (PACS): A progressive approach with small systems

PACS represents the natural evolution from working with digital modalities (e.g. CT, US, MRI, CR) towards a global digital environment where the film based activities are progressively replaced by their digital counterpart. The advantages of the technique and the drawbacks of the first implementations are described, as well as the recent advances in terms of technology, architecture, medical integration and cost-effectiveness. The so called ‘second generation’ PACS concept is presented with its features: modular architecture, progressive implementation, multi-vendor environment, integration with the Hospital Information System, standardization. This approach is particularly suited for progressive implementation in an existing hospital, in contrast to the possible topdown construction of a filmless radiology department, as a project for a totally new hospital. The implementation into the university hospital AZ-VUB is described as case study.     

PACS-based functional magnetic resonance imaging.

The picture archiving and communication system (PACS) technology reaches its 10th anniversary. Retrospectively no one could foresee the impact the PACS would have to the health care enterprise, but it is common consent today, that PACS is the key technology crucial to daily clinical image operations and especially to image related basic and clinical research. During the past 10 years the PACS has been matured from a research and developmental stage into commercial products which are provided by all major modality and health care equipment vendors. The PACS, originally implemented in the Radiology Department, needs to grow and has already carried well beyond departmental limits conquering all image relevant areas inside the hospital. During the past 10 years a dramatic development in imaging techniques especially within MRI emerged. Advanced 3D- and 4D-MR imaging techniques result in much more images and more complex data objects than ever before which need to be implemented into the existing PACS. These new imaging techniques require intensive post-processing apart from the imaging modality which need to be integrated into the image workflow and the PACS implementation. Along with these new imaging techniques new clinical applications, e.g. stroke detection, and research applications, e.g. study of heart and brain function, in Neurology and Cardiology require changes to the traditional PACS concept. Therefore inter-disciplinary image distribution will become the high-water mark for the next 10 years in the PACS endeavor. This paper focuses on one new advanced imaging technique, functional magnetic resonance imaging (fMRI), and discusses how fMRI data is defined, what fMRI requires in terms of clinical and research applications and how to implement fMRI in the existing PACS.     

影像存档与通讯系统网络结构设计和优化因素

目的 探讨影像存档与通讯系统（PACS）的网络结构设计及其优化因素,方法 基于上海市第一人民医院的系统对PACS的网络结构以及功能和过程在网络带宽和传输方面的需求进行测试。使用旬工作站内置的影像传输检测功能和Windwos NT的网络监控软件作为测试工具,结果 在静态测试环境下,除路由设备之外,各类网络构件对带宽和传输率的影响无明显差异,在动肪环境测试,交换机提供的影像传输速度明显高于集线器,局部系统通讯速率亦较全局系统通讯高,结论 PACS网络结构设计的优化因素主要是简化网络布局和转换全局通讯任务为数个简单的局部系统通讯;优化的要点是确保医学影像诊断过程必需的带宽使用。     

PACS adoption

Once the decision has been made to adopt PACS instead of a film-based radiology practice, there are a number of hurdles to jump. Users need to be aware of the impact the change will make on end users and be prepared to address issues that arise before they become problems. Someone who understands the technology of PACS must be identified to help make an informed decision about vendor selection, network architecture, workstation functionality, and archives. A PACS administrator should have the tools available to avoid problems with the system after implementation and should be able to repair the inevitable mistakes that will happen. Hopefully, this article can serve as a starting point for a potential new PACS adoption.     

图像存储与传输系统的总体设计与分步实施

目的 探讨在组建图像存储与传输系统（picture archiving and communication system,PACS)过程中的总体设计及如何进行具体每一步的实施方案。方法 把具有医学数学成像及通讯（digital imaging and communication in medicine,DICOM)标准接口或非DICOM标准接口的影像设备进行联网，制定资源共享、系统存储的解决方案，建立典型的医院放射科PACS系统，连接目前医院现有的设备，服务器采用Windows NT SQL Server 7.0组成，解决管理及存储问题，工作站基于浏览（WEB）方式访问，扩大客户端的使用权限（license)，数量为100个，磁盘阵列（RAID 5）在线存储3个月，线性磁带库（DLT)离线海量存储；扩展全院并解决放射学信息系统（radiology information systems,RIS)、PACS的数据共享连接；建立地区影像数据交换中心。结果 建立了典型的医院放射科PACS系统，连接了目前医院现有的设备，实现了放射科初步的无胶片化方式；将PACS扩展到了全院的临床科室、手术室、急诊室等，以及实现了和已有的医院信息系统（hospital information systems,HIS)、其他医院网络联网，建立起了影像数据中心；实现了和本地区其他医院及其他地区的影像数据中心的联网，使用起来较为得心应手，方便了医生，提高了工作效率。结论 实践证明，上述PACS的总体设计与分步实施方案是可行的、成功的。     

Impact of manual and computer-assisted PACS for automated PACS

Considerations of totally electronic picture archiving system (PACS) often neglect the fact that every radiology practice currently has some system for storing and retrieving images and related alphanumeric data. Although these systems are usually manual, many departments now use on-line computers to help manage film flow. In either event, the creation of electronic PACS can be viewed as a classic data processing problem of automating an existing system, and the conversion should proceed through the usual steps of documenting the existing system in detail, and conducting feasibility studies and cost-benefit analyses. Documenting current systems should be facilitated by computer-assisted PACS--particularly documenting transaction volumes which can be provided as a by-product of radiology information management systems. Similarly cost-benefit analysis should be facilitated, although the cost/benefit ratio may be less favorable when comparing automated to computer-assisted PACS. Finally, information management features such as those provided by current on-line radiology systems provide a framework necessary to realize the full benefits of automated PACS.