PACS and Web-based image distribution and display

PAC system is extending increasingly from the now well-established radiology applications into a hospital-wide PACS. New challenges are accompanying its spread into other clinical fields. With awareness of the importance of PAC systems among various medical experts, this system has been enhanced through the PAC system's pipeline, and simplification of image display for analysis via an interaction with the user. Generally PAC system consists of medical image, patients' data acquisition, storage, and display subsystems integrated by digital networks and application software. PAC system facilitates the systematic utilization of medical imaging for patient care. However, even though PAC system consist of medical image, data acquisition, storage and display subsystems, most of available PAC system does not have image analysis as required by the clinical expert. If the PAC system do have this element, it need interaction or interference from the clinical expert as user, and the PAC system storage mostly is an unstructured storage with no analysis element and report modules. And unfortunately in most cases, for the web-based PAC system, there are delayed in retrieval and visualize the required image from outside of the hospital. Most of the PACS with function of 3D display, it did not communicate information clearly and efficiently to users (clinical expert). Most of the visualization did not visual accurate information as required by the clinical expert. These listed constraints limited the clinical expert perspective regarding his/her decision. From market validation observation we concluded that most of the PAC system available in market does not have medical image processing functions for the purposes of decision analysis with minimum user interaction. Research towards this limitation has been conducted in accordance with the needs of clinical experts. Among these studies are: (i) angiography image processing for stenosis position detection and measurement of its dimensions, (ii) echocardiography image processing for detection of ventricular cardiac abnormalities (walls and volume) and (iii) 2D angiography images reconstructed to 3D images for display purposes and to identify the location of artery tree. With the result of these studies, the PAC system will integrate with extra modules, which are: i) 3D reconstruction function from single image angiogram with identification of the stenosis location, ii) Identification of abnormality heart wall chamber, iii) 3D reconstruction echocardiography left and right ventricular heart, and iv) 3D fused within CTA, angiography and MRI. As stated above, the common limitation for the web-based PAC system is the delayed in retrieval and visualize the required image from outside of the hospital/clinics. To overcome this limitation, we proposed a technique and integrated a related function for faster transmission of the processed image without sacrifice any importance information. And to complete the PAC system so that the new PAC system able to compete with current PAC system that available in market, we link the PACS with our Patients Clinical Record Database with report modules as required by the medical expert. The outputs of all those said researches will be integrated with the PAC system where each research output has been tested and validate by numbers of cardiac expert, the patients clinical record database has been tested in UKMMC and the PAC system currently being beta tested in a Private Clinic in Kelang, Selangor, Malaysia. Eventually the PAC system with the Patients Clinical Record Database will be integrated with these image analysis and 3D image visualization and it is plan to be tested in Veterinary Hospital of Universiti Putra Malaysia. To forward this project to commercialization activity, we have distributed questioners to Clinics in area Bangi (Selangor, Malaysia) and Nilai (Negeri Sembilan, Malaysia). There are 58 Medical, Veterinary and Dental Clinics received the questioner (currently we expand the distribution towards Serdang and Kajang (Selangor, Malaysia). Out of 58 clinics; a) 16% interested to collaborate and looking forward to see PAC system, b)8% interested with the PAC system but do not willing to have any demo, c) 44% not interested but open for demo of system, d) 28% not interested and not willing to have demo system and e) 4% return the form without answered for that particular question. To secure and protect the ownership, each research output has been submitted for Patent filed in Malaysia and with three chosen country, where 2 of the patent filed has been granted in Malaysia. We also copyrighted each module. This project has been selected by Universiti Putra Malaysia to be commercialized by a startup company seeded by UPM (CASD Medical Private Limited) under program INNOHUB. We realize to implement the complete PAC system in Hospital there are 10 main problems exist that we might need to overcome or try to minimize the consequences. These problems are; i) Integration with the Hospital Information System. Although a lack of inter-vendor device and IT integration can often make the problem worse, the market is improving as providers and meaningful use demand greater integration. Unfortunately, still, many radiologists and PACS administrators prefer to make full use of hospital IT to configure their own systems and achieve a bit more autonomy, ii) Every system has downtime where we need to establish alternate workflows. Both scheduled and unscheduled, but they need not have to be too serious to minimize the effect on patient care, iii) Non-standardized hanging protocol display is a common and pesky challenge for PACS users. Images from different modalities are not organized by default even though each of them generally will be transmitted through DICOM format getaway, each study takes a little longer to read. As the number of scanners increases and the sample of vendors expands, the problem grows worse, iv) Integration problems concern hardware, from digitizing pre-DICOM modalities to integrating systems for advanced image reconstruction. Add-ons like a DICOM converter can help squeeze out additional value from older CT, angiography and fluoroscopy systems, v) As with downtime, failures are unavoidable, there is a need to demonstrate strong support activities, vi) Effective training can be a cost-effective way to demonstrate to administrators and physicians many of PACS' underused and undervalued features. Training wil help to expose staff to what the system can do to make their jobs easier and more efficient, vii) The migration of data to the new PACS is often the most challenging part of the process, both in negotiating the release of data from the current PACS and in sorting out all the data entry errors that have accumulated over the lifespan of the system, viii) As other specialties realize the value of PACS, the system is slowly being taken out of radiologists' hands. PACS has become a mission-critical enterprise-wide tool used by nearly all specialties. With this change, decision-making for PACS-related purchases, upgrades and configurations has, in some cases, shifted from radiologists to a more central process, ix) Hiring a certified public ergonomist to evaluate the department's workstations can ease radiologists' repetitive stress symptoms and contribute substantially to productivity. Despite accelerating advances in technology, many interface tools have changed little since the introduction of PACS, and finally x) Like business continuity, disaster recovery can prevent a painful experience from becoming fatal. Many hospitals opt for either redundant servers, cloud storage or both. At the very least, preparation for downtime can spare physicians and patients from experiencing significant losses. To minimize the consequences of the listed 10 main problems, this project (in early stage) targeting potential customers among the owner of the small private clinics where the numbers of patients is less and the bureaucracy of the administration is limited.

The picture archiving and communication system (PACS) originated as an image management system for improving the efficiency of radiologic practices. It has evolved into a hospital-integrated system that stores information media in many forms, including voice, text, medical records, waveform images, and video recordings. The integration of these various types of information requires the technology of multimedia, including hardware platforms, information systems and databases, communication protocols, display technology, and system interfacing and integration. The purpose of this book is to discuss the conceptual and technologic advances in PACS development for all of these previously mentioned technologies. The book also emphasizes the growing field of PACS-based imaging informatics, where existing PACS resources are used for largescale horizontal and longitudinal clinical service, research, and education applications. The book is intended for those who are involved in a health care environment that manages the everyday practical realities of PACS planning, operation, and maintenance. The book will also serve as excellent curriculum material for the training of PACS information technology personnel because the author provides comprehensive concepts that tie medical imaging, medical physics, information technology, and clinical workflow with enterprise PACS (multiple, hospital-wide PACS). The author, H. K. Huang, has been involved in PACS development since the 1980s and is a leading scientist in the field. The book is divided into five parts and 23 chapters. Part 1, titled “Medical Imaging Principles,” summarizes the history of PACS, the fundamental concepts of digital medical imaging, and the different types of modalities integrated into PACS. Part 2, titled “PACS Fundamentals,” describes in detail the PACS subsystems and industry standards (Digital Imaging and Communications in Medicine and Health Level 7) that are used to integrate PACS with the hospital information system and radiology information system. Part 3, titled “PACS Operation,” describes the practical problems encountered by PACS administrators and users and discusses different techniques to solve these problems, with many examples from installed PACS sites around the world. Because the author developed PACS at the University of California, Los Angeles, in 1991 and the University of California, San Francisco, in 1995, he is able to draw from his expertise on the subject. The author also uses his experience from developing many state-of-theart prototypes (eg, fault tolerant storage system) funded by research grants. Part 4, titled “PACS-based Imaging Informatics,” presents image-processing techniques that can be used to mine the huge image and clinical data resources stored in the PACS archive. The analysis of lung nodules by using temporal computed tomographic and contentbased image indexing are some of the examples of advanced processing applications applied to PACS data mining. Part 5, titled “Enterprise PACS,” describes different models for implementing an enterprise PACS in terms of the architectural design of the system and financial and business models. This new book builds on two previous volumes on PACS that were written by the author. The text, image collections, and schematic diagrams in this current work achieve the author’s goal of providing up-to-date material concerning the technologic advances in PACS and imaging informatics. The text serves as a guide for those who are planning an enterprise PACS and provides teaching material for training PACS developers in industry and health care. The author has used portions of this book as lecture material for graduate courses at leading universities in the United States and abroad. The author also uses many examples to emphasize that the integration of heterogeneous health care information systems is becoming more complex and that, as more radiologists and clinicians expect higher standards in the reliability of the data, a systemic understanding of Digital Imaging and Communications in Medicine, Health Level 7, and Integrating the Healthcare Enterprise becomes ever more important to optimize enterprise workflow. The strength of the book lies in the vast experience that the author, who has implemented PACS at numerous institutions in the United States and abroad, has transmitted into this new book. Huang has conducted first-hand analysis of the various systems from PACS manufacturers that are used in clinical operation at large medical institutions and has performed up-to-date research in data mining of the huge image and data resources stored in the PACS repository.

The goal of this study was to determine if our neuroradiology picture archiving and communication system (PACS) is capable of improving the efficiency and function of the management and review of neuroradiologic images. A neuroradiology PACS module developed in our department was evaluated in the clinical environment from February 1990 through July 1991. The overall evaluation focused on three aspects: (1) image delivery performance, (2) system availability, and (3) user acceptance. Image delivery performance was evaluated by analyzing the time spent on each modularized task with both the film-based system and the PACS system. The system availability was examined by observing the downtime occurrence and uptime probability of individual hardware components in the PACS module. User acceptance was evaluated through a survey done with the display workstation. Under regular operating conditions, the PACS outperforms the current film-based operation. The overall PACS module availability is more than 92%, with the display workstation available more than 99% of the time. The overall user acceptance of the system is 3.4 on a four-point ranking scale. This study has demonstrated the full functionality and clinical usefulness of our neuroradiology PACS. On the basis of the results of this study, a large-scale PACS has been designed and implemented in our department.

Web-based integration methods can be used to resolve a fundamental issue in the transition from film to a picture archiving and communication system (PACS): the identification of relevant prior studies only available on film. Even in the most ambitious conversions from a film-based environment to PACS, there are issues regarding prior studies not on PACS. Failure to compare with prior exams is one of the known risk factors for malpractice in radiology. While most commercial PACS systems today have some degree of RIS integration, knowledge of prior studies is usually limited to an awareness of studies in the PACS. On the other hand, most RIS systems today do not or cannot distinguish between studies on film and those in PACS. We made the observation, from a set theory perspective, that in general: Therefore we sought to create a system that would query both the RIS and PACS and reconcile the results using the above set operation. The query is initiated from a display station via the invocation of a Web browser installed on that station. The process of starting the browser is implemented using a scripting language provided by the workstation vendor, though the use of other mechanisms, such as the CCOW (Clinical Context Object Workgroup) or IHE (RSNA Integrated Healthcare Enterprise) interfaces, can be supported by this architecture. The medical record number, which identifies the current patient and is the primary parameter of the query, is passed as part of the URL (Universal Resource Locator) used to launch the browser. Once running, the browser connects to a Web server that hosts a JSP (Java Server Page) page that performs a DICOM query of the PACS and an HL7 query of the RIS, and then collates the results using the set operation described above. Both the DICOM and HL7 functionality are provided by Java-based toolkits developed in house. The results are returned to the client's browser as a standard HTML page with a tabular format detailing which studies are on PACS and which are available only on film. The responsiveness of the system in terms of time required to complete the two queries and display the results was measured. In addition, the number of diagnostic reports, whose retrieval was triggered by the results of the queries, was monitored to determine the overall performance and use of the system. This project demonstrates that, with minimal modification of commercial software, Web-based integration methods exist to enable patient-context sensitive queries from the diagnostic workstation that identify relevant prior studies that exist only on film and are unknown to the PACS. As a result radiologist workflow is enhanced by the elimination of the need to consult a physically separate system for this type of information. In addition, quality of service is improved by providing more accurate and easier identification of relevant prior studies.

Enterprise-wide PACS: Beyond Radiology, an Architecture to Manage All Medical Images 1

Objective: This research investigates the needs and opinions of radiologists on the use of enhanced information technologies and approaches to improve the functionality of Picture Archiving and Communication Systems (PACS). Method: Six interviews were conducted in the main governmental hospital in Kuwait (AL-Sabah Hospital) with radiologists, including two senior radiologists, two junior radiologists, and two trainee radiologists undertaking the Irish radiology board. Results: The radiologists identified a number of limitations that exist in current PACS and requirements to enhance usability and functionality. However, it was the case that some of the radiologists had little knowledge about the advanced trends in PACS. Four themes emerged from the thematic analysis of the data: (1) limitations of traditional PACS; (2) Features and requirements that can increase PACS functionality; (3) web based solutions of PACS; (4) PACS in mobile phones. Conclusion: It is widely recognized that PACS has limitations. This research has identified themes that, when incorporated, will enhance the functionality of PACS and provide better quality clinical practice. This research has determined the important future trends of PACS. Primarily web based solutions and use in mobile phones. The findings from this research can be used as recommendations to vendors, for product development and medical institutes to consider when undertaking implementation of PACS and training future radiologists.

Picture archiving and communications systems (PACS)

Picture archiving and communication systems (PACS) is a current research topic in both the United States and Japan. During the past 6 years, our department has been working in this field very closely with our colleagues in Japan. In July 1 986, we attended the Third International Symposium on Picture Archiving and Communication Systems/Personal Health Data Recording Systems (JPACS) in conjunction with the Fifth Symposium on Medical Imaging and Technology (JAMIT) at the National Cancer Center in Tokyo. After the meeting, we visited various PACS research and development laboratories at major imaging manufacturers and hospitals. We summarized our impressions in a commentary: “Picture Archiving and Communication Systems in Japan” [1 ]. Since then, we have successfully implemented two PACS modules, one in the pediatric radiology section and one in the coronary care unit [2, 3]. More than 200 visitors from Japan have come to see our facilities. Among these visitors was Professor T. Takahasi from Kyoto University Hospital, who was the program chairman of the Eighth Symposium of JAMIT/Sixth International Symposium on PACS in July 1 989. After his visit, he extended an invitation to us to give the keynote speech, “Recent Progress in PACS” for the meeting. We took this opportunity to go back to Japan and repeat the hospital and laboratory tour in order to observe their research and development progress in PACS during the past 3 years. This paper is a summary of our opinion ofthe changes that have occurred in Japan since our last visit of the status of PACS in that country compared with that in ours. The JAMIT Meeting and the JPACS Meeting

In recent times, technological advancements have remarkably improved picture archiving and communication system(PACS) capabilities beyond their conventional use in radiology departments. Researchers and instructors have started employing PACS functionalities to improve medical research processes, promote interdisciplinary collaborations, and facilitate learning. To illustrate this point further, the PACS enables researchers to handle and analyze huge amounts of imaging data with superior precision and speed, supporting innovative studies in areas like disease progression, treatment outcomes, and imaging modalities. Moreover, a PACSintegrated with artificial intelligence (AI) algorithms leads to significant improvements in image processing, diagnostic accuracy, and personalized treatment, thus marking a new approach to medical imaging. The PACSsupported by AI is mostly transformative since they allow for improved early disease detection capabilities as well as automated image processing and decision assistance, which increase diagnostic accuracy and clinical outcomes. Such systems can rapidly process large quantities of visual data with an accuracy rate surpassing earlier endeavors. In medical research, however, combining PACSwith AI allows challenging imaging datasets to be examined, thereby making findings that were not previously possible. The capacity to combine imaging outcomes with clinical information is valuable for medical students and professionals in the field of education. They can access extensive medical image collections and case studies using PACS. This link is critical for teaching and learning as it allows students to interact with concrete events and improve their diagnostic accuracy in a controlled environment. This review discusses how the PACS affects educational courses and clinical outcomes based on the available literature. Our aim was not only to outline recent research or developments but also to present a comprehensive overview regarding the growing role played by PACS in the modern healthcare system and academics. Similarly, we look at the challenges and opportunities associated with the wide adoption of PACS, highlighting possible future areas of study or teaching methodologies. Issues such as data security, interoperability, and the need for defined protocols are included to give an exhaustive understanding of what PACS can and cannot do. Through this study, we stress PACS's revolutionary potential in advancing research methodology and educational practices, eventually contributing to enhanced patient care and knowledge dissemination in healthcare areas. The continual growth of PACS technology and its applications is expected to reshape the landscape of medical research and education, making it a vital component in the quest for medical excellence. By knowing the present trends and future potential, stakeholders in healthcare and education may better employ PACS to reach their objectives and boost overall results.

Policies and procedures (P&P) constitute the mechanism for planning, standardizing, and documenting the provision of clinical services. Upon approval by hospital management, the P&P is an official statement of hospital rules and regulations. Each P&P establishes organizational responsibility for providing services. P&P are a mechanism for communicating standard operating procedures to hospital and medical staff. P&P serve as a reference document for unusual events, as well as routine procedures. P&P are often reviewed by inspection teams from the Joint Commission on Accreditation of Hospital Organizations (JCAHO) to determine whether the hospital has documented systematic practices. A picture archival and communications system (PACS) provides a new vehicle for providing radiology services. P&P that were designed for conventional film-based imaging are often not appropriate for electronic imaging. Because PACS is new and not yet widespread, good examples of PACS P&P are not yet available. JCAHO has no official requirements for PACS: PACS is viewed only as a means for the hospital to accomplish its work. Successful P&P development is a team effort, drafted by personnel responsible for executing the procedure, assisted by staff proficient in PACS technology, and tested in the field. The P&P should be reviewed and approved by management personnel knowledgeable about hospital and imaging operations. P&P should be written in clear and concise language. Successful P&P development is an ongoing effort. P&P must be periodically reviewed and updated to reflect changes in PACS technology and changes in clinical operations. New P&P must be developed when a deficit is noted. PACS security is a good example of a topic worthy of P&P development, especially in the face of the Health Insurance Portability and Accountability Act (HIPAA) legislation of 1996. What are the provisions for access control? Does the system include a feature for automatic shut-off of the software? Are there "generic" passwords and log-ins shared by a community of users? How are passwords assigned and how frequently are they changed? What security measures are in place to assure passwords are given to the appropriate user? Who grants and denies access? Service calls are another topic for P&P. Who initiates a service call? What is the process for escalating a service call from the operator level to the vendor? What immediate actions are expected by the operator in order to restore PACS services? How are service events documented? Who is responsible for determining when "downtime" procedures should be initiated or suspended? When our hospital's total electrical system had to be shut down for an extended period, we found that a P&P was lacking for a task as mundane as shutting down and restarting our PACS components. What is the sequence for the shutdown? Who is responsible for shutting down and restarting? How long can the devices operate on uninteruptible power supplies (UPS)? What components are on emergency power? Should we expect the components to survive the switchover to generator power? Developing this P&P was worth the effort: it made the PACS more fault-tolerant and served as a reference document 3 years later when expansion of our physical plant required two more power outages.

The most frequently asked question without a correct answer is: "Just how many people does it take to operate a picture archiving and communication system (PACS)?" At Texas Children's Hospital, our consensus is that we do not yet know. As soon as we felt we had adequate staffing to provide timely response for routine services, we found that including the Intensive Care Units (ICUs) increased our demand for urgent response beyond our capacity. The addition of inpatient bedside imaging to PACS also increased the demand for round-the-clock and weekend PACS services. Our answer to the staffing question changes every year, in accordance with changes in the scope of services that our PACS is expected to provide. Our administration drew up a 5-year plan for PACS implementation, concentrating on purchase and installation of equipment, but neglected to estimate requirements for full-time equivalents (FTEs) for PACS. Our administration reasonably assumed that existing employees would be galvanized into PACS personnel. It is now clear that new FTEs need to be created strictly for the PACS service. Our 5-year plan also did not anticipate significant changes in the extent of our healthcare enterprise. Our PACS accommodates limited remote service: providing a PACS Analyst to travel to the site when a problem is not resolved remotely is another demand on staffing. Our PACS service was formed using staffing numbers based on assumptions about the minimum number of employees needed to perform routine duties, field trouble calls, conduct training, and work on special projects, such as adding new acquisition modalities or troubleshooting longstanding problems. This staffing was based on a single shift operation, with on-call coverage for second, third, and weekend shifts. The number of employees also considered absences for vacation, sick leave, and training. The service has administrative overhead that should be covered by a secretary. Someone is also needed to supervise the team. Once the number of personnel is determined, detailed definition of qualifications and responsibilities is required. Each job description must accurately reflect what is expected of the employee, but must be constructed in such a way to be graded appropriately by Human Resources, without excluding potentially desirable applicants. In addition to competitive pay, other factors play an important role in recruiting and retention. These include training that the hospital provides, opportunities for advancement, relief from menial duties, adequate working space and facilities, and opportunities for self-development. There is high turnover of personnel in computer services, and we are in a highly competitive market. The correct number of FTEs must consider that we will have to operate the PACS during periods when one or more positions are open or occupied by "greenhorns." In our case, where the vendor provides on-site service engineers, we are able to operate with fewer FTEs. The more distant and tenuous our vendor support, the more we would need to depend on hospital FTEs. While remote vendor maintenance is helpful, it is not useful in reducing the number of FTEs. Instead of adding PACS responsibilities to supervisors of imaging services, we are creating new PACS FTEs outside the PACS service. The idea is to give imaging supervisors the assets they need to perform the additional tasks involving PACS, such as first-line response to trouble, user training, and quality-control oversight. It also frees up PACS service personnel to deal with training and problems with customers outside the Radiology Department.

Avoiding Unread Images with PACS

Integrating the Healthcare Enterprise-Japan (IHE-J) was established in Japan in 2001 and has been working to standardize health information and make it accessible on the basis of the fundamental Integrating Healthcare Enterprise (IHE) specifications. However, because specialized operations are used in nuclear medicine tests, online sharing of patient information and test order information from the order entry system as shown by the scheduled workflow (SWF) is difficult, making information inconsistent throughout the facility and uniform management of patient information impossible. Therefore, we examined the basic design (subsystem design) for order entry systems, which are considered an important aspect of information management for nuclear medicine tests and needs to be consistent with the system used throughout the rest of the facility. There are many items that are required by the subsystem when setting up an order entry system for nuclear medicine tests. Among these items, those that are the most important in the order entry system are constructed using exclusion settings, because of differences in the conditions for using radiopharmaceuticals and contrast agents and appointment frame settings for differences in the imaging method and test items. To establish uniform management of patient information for nuclear medicine tests throughout the facility, it is necessary to develop an order entry system with exclusion settings and appointment frames as standard features. Thereby, integration of health information with the Radiology Information System (RIS) or Picture Archiving Communication System (PACS) based on Digital Imaging Communications in Medicine (DICOM) standards and real-time health care assistance can be attained, achieving the IHE agenda of improving health care service and efficiently sharing information.

Clinical Data Warehouses (DWHs) are used to provide researchers with simplified access to pseudonymized and homogenized clinical routine data from multiple primary systems. Experience with the integration of imaging and metadata from picture archiving and communication systems (PACS), however, is rare. Our goal was therefore to analyze the viability of integrating a production PACS with a research DWH to enable DWH queries combining clinical and medical imaging metadata and to enable the DWH to display and download images ad hoc. We developed an application interface that enables to query the production PACS of a large hospital from a clinical research DWH containing pseudonymized data. We evaluated the performance of bulk extracting metadata from the PACS to the DWH and the performance of retrieving images ad hoc from the PACS for display and download within the DWH. We integrated the system into the query interface of our DWH and used it successfully in four use cases. The bulk extraction of imaging metadata required a median (quartiles) time of 0.09 (0.03–2.25) to 12.52 (4.11–37.30) seconds for a median (quartiles) number of 10 (3–29) to 103 (8–693) images per patient, depending on the extraction approach. The ad hoc image retrieval from the PACS required a median (quartiles) of 2.57 (2.57–2.79) seconds per image for the download, but 5.55 (4.91–6.06) seconds to display the first and 40.77 (38.60–41.63) seconds to display all images using the pure web-based viewer. A full integration of a production PACS with a research DWH is viable and enables various use cases in research. While the extraction of basic metadata from all images can be done with reasonable effort, the extraction of all metadata seems to be more appropriate for subgroups.

Objective To evaluate the teaching effects of case introduced method based on pic- ture archiving and communication system （ PACS ） system in medical imaging course. Methods Totally 148 students （ 2009 grade ） majored in five-year clinical medicine from Xiangya Medical College were divided into 10 groups; the 10 groups were taken randomly as control group （ n=75 ） and experimental group （ n=73 ）. Control group used traditional teaching methods （ film teaching ） while experimental group used case introduced method based on PACS system. Effects of teaching between were evaluated by questionnaire and test. χ^2 test was used to compare students＇ theoretical test scores, with α level = 0.05. Results Based on results of questionnaires, more students in experimental group than in control group hold that case introduced method based on PACS system can achieve the purpose of teaching, improve interests in learning, and strengthen the mastery of knowledge. Test scores showed that the percentage of students scored 90-100 and 80-89 （ respectively 14%, 75% ） in experimental group was significantly higher than that in control group （respectively 5%, 66% ） （χ^2 =17.932, P=O.O00 ）. Conclusions Application of case introduced method based on PACS system in medical imaging course not only improve students＇ motivation to learn and their clinica~ ability-, but also allow teachers to find and correct short- comings of students timely, therefore, it is worth promoting. Key words: Picture archiving and communication system; Case introduced method; Prac-tice teaching