Zusammenfassung Das CHILI-Teleradiologienetzwerk besteht aus mehr als 60 installierten Systemen in Deutschland und den USA. Radiologische Bilder und kardiologische Multiframebilder werden mit Hilfe des CHILI-(Tele-)Radiologiesystems in Routine ausgetauscht. In diesem Artikel wird untersucht, wie das System im klinischen Betrieb eingesetzt wird. Dies geschieht auf der Basis von Logfiles, die durch das System generiert werden. In diesen Dateien werden die verwendeten Funktionen und Protokolle, die Menge der importierten Daten, durchgeführte Übertragungen, und weitere wichtige Informationen gespeichert. Betrachtet werden Zeitpunkt und Anzahl der Bildimporte für die einzelnen Modalitäten sowie die zur Datenübertragung verwendeten Methoden und Protokolle. Es werden unterschiedliche Aspekte der Telekonferenz betrachtet und schließlich medizinische Anwendungsszenarien in den verschiedenen Einsatzumgebungen beschrieben. Ein wichtiges Ergebnis dieser Evaluation ist, dass das System nicht nur als Notfallsystem dient, sondern darüber hinaus im täglichen Gebrauch als allgemeine multifunktionale Workstation mit fortgeschrittenen Funktionen für Teleradiologie und Telekardiologie eingesetzt wird.

The CHILI teleradiology network has more than 60 installations in Germany and the USA. Radiological images and cardiological multiframe series are exchanged in clinical routine. This article investigates in what way and how often the system is used. This is done by means of accounting files that are produced automatically by the system. User functions, transmission protocols, data quantity, frequencies and time of data transmission and teleconferences are evaluated and discussed in this paper. Different application scenarios have been identified and are described and analyzed as well. An important result is, that the system is not merely an emergency system. Instead, it is used in daily routine as a multifunctional, multimodality workstation with advanced features for teleradiology and telecardiology.

This paper is a subjective view based on 8years of personal experience in teleradiology.We think the results are of interest totelemedicine in general.Telemedicine is a broad field, which can bedefined in different ways. A Japanese defini-tion of 1996 described it as ‘‘… the use of anyelectrical signal to transmit medical informa-tion…’’ [1]. This is a very technical and sim-plistic view. The University of Athens inGreece published a more detailed definition:‘‘… the transfer of electronic medical data(i.e. high resolution images, sounds, livevideo, and patient records) from one locationto another.’’ [2]. A broader definition, whichtakes the entire health care system into ac-count, says: ‘‘… the use of telecommunica-tions technology to deliver health careservices and health professions education tosites that are distant to the host site or educa-tor…’’ [3].The driving factors in telemedicine wereinvestigated in a study by Frost and Sullivan[4]. The following reasons were identified fordeveloping and using telemedicine: first, thereis pressure to reduce costs. Centralization,specialization and outsourcing need this tech-nology. Furthermore, there is a need forgreater efficiency in the health care system.Advances in technology help in implementingtelemedicine systems today. The dissemina-tion of international standardization is animportant aspect in implementing systemsthat are interoperable. Examples of suchstandards are DICOM, MEDICOM andHL7. The shift from institution-based care tocitizen- and homecare-centered provision isanother important driver. Increased health-care demands can only be satisfied withtelemedicine. Aging populations need tele-monitoring to cut costs and isolated patientsneed and demand full healthcare services.Physicians are motivated to implementtelemedical applications since they recognizean income potential [4].Telemedicine can help patients, physiciansand other medical staff as well as medicalinstitutions, insurance carriers, politiciansand the medical devices market according tothis study [4].

This paper describes a PACS project which is based on Intel platforms and the Linux operating system. It describes the goals and requirements of the radiologists, the realized hardware and software architecture and specific features, like fault tolerance, security measures, teleconferencing and extensibility of the system.

Teleradiology is one of the most evolved areas of telemedicine, but one of the basic problems which remains unsolved concerns system compatibility. The DICOM (Digital Imaging and Communications in Medicine) standard is a prerequisite, but it is not sufficient in all aspects. Examples of other currently open issues are security and cooperative work in synchronous teleconferences. Users without a DICOM radiological workstation would benefit from the ability to join a teleradiology network without any special tools. Drawbacks of many teleradiology systems are that they are monolithic in their software design and cannot be adapted to the actual user's environment. Existing radiological systems currently cannot be extended with additional software components. Consequently, every new application usually needs a new workstation with a different look and feel, which must be connected and integrated into the existing infrastructure. This paper introduces the second generation teleradiology system CHILI. The system has been designed to match both the teleradiology requirements of the American College of Radiology (ACR), and the functionality and usability needs of the users. The experiences of software developers and teleradiology users who participated in the first years of the clinical use of CHILI's predecessor MEDICUS have been integrated into a new design. The system has been designed as a component-based architecture. The most powerful communication protocol for data exchange and teleconferencing is the CHILI protocol, which includes a strong data security concept. The system offers, in addition to its own secure protocol, several different communication Methods: DICOM, classic e-mail, Remote Copy functions (RCP), File Transfer Protocol (FTP), the internet protocols HTTP (HyperText Transfer Protocol) and HTTPS (HyperText Transfer Protocol Secure),and CD-ROMs for off-line communication. These transfer METHODS allow the user to send images to nearly anyone with a computer and a network. The drawbacks of the non-CHILI protocols are that teleconferences are not possible, and that the user must take reasonable precautions for data privacy and security. The CHILI PlugIn mechanism enables the users or third parties to extend the system capabilities by adding powerful image postprocessing functions or interfaces to other information systems. Suitable PlugIns can be either existing programs, or dedicated applications programmed with interfaces to the CHILI components. The developer may freely choose programming languages and interface toolkits. The CHILI architecture is a powerful and flexible environment for Picture Archiving and Communications Systems (PACS)and teleradiology. More than 40 systems are currently running in clinical routine in Germany. More than 300,000 images have been distributed among the communication partners in the last two years. Feedback and suggestions from the users influenced the system architecture by a great extent. The proposed and implemented system has been optimized to be as platform independent, open, and secure as possible.

This paper proceeds from the definition of teleradiology. It identifies three different generations of teleradiology systems and includes those systems that are not regarded as teleradiology systems by the authors. A list of requirements pertinent to users of first-generation teleradiology systems is introduced. Most of the requirements have been realized in a new generation teleradiology system called CHILL.

MEDICUS is a teleradiology system which has been developed in a joint project of the German Cancer Research Center (Deutsches Krebsforschungszentrum) and the Transfer Center Medical Informatics (Steinbeis-Transferzentrum Medizinische Informatik) in Heidelberg, Germany. The system is designed to work on ISDN lines as well as in a local area network. Special attention has been given to the design of the user interface and data security, integrity, and authentication. The software is in use in 13 radiology departments in university clinics, small hospitals, private practices, and research institutes. More than 25 thousand images have been processed in 6 months. The system is in use in six different application scenarios. MEDICUS is running under the UNIX operating system. The connection of the modalities could in most cases not be realized with the DICOM protocol as older machines were not equipped with this standard protocol. Clinical experiences show that the MEDICUS system provides a very high degree of functionality. The system has an efficient and user friendly graphical user interface. The result of a comparison with other systems shows that MEDICUS is currently the best known teleradiology system. Cost reductions are already obvious, but additional research has to be performed in this field. An even more powerful commercial successor is currently under construction at the Steinbeis-Transferzentrum Medizinische Informatik in Heidelberg.

This paper describes the evolution of a german teleradiology system. The development started from simple image file transfer, continued with a dedicated teleradiology system and ended up with a general radiology workstation with teleradiology features. The main features, advantages and drawbacks of the different generations are described. The own developments are compared with developments at other places. The influence by standards is also included in this investigation The latest systems are mainly used by the radiologists and the image transfer for scientific cooperation is nowadays just one of several application fields of teleradiology.

This paper proceeds from the definition of teleradiology. It identifies three different generations of teleradiology systems and also includes those systems that are not regarded as teleradiology systems by the authors. A list of requirements pertinent to users of first generation teleradiology systems is introduced. Most of the requirements have been realized in a new generation teleradiology system called CHILI.

Evaluation of the CHILI teleradiology network after 4 years in clinical routine Abstract The CHILI teleradiology network has more than 60 installations in Germany and the USA. Radiological images and cardiological multiframe series are exchanged in clinical routine.This article investigates in what way and how often the system is used.This is done by means of accounting files that are produced automatically by the system. User functions, transmission protocols, data quantity, frequencies and time of data trans- mission and teleconferences are evaluated and discussed in this paper. Different appli- cation scenarios have been identified and are described and analyzed as well. An im- portant result is, that the system is not merely an emergency system. Instead, it is used in daily routine as a multifunctional, multimodality workstation with advanced features for teleradiology and telecardiology.