Reprint from:
Lemke HU, Vannier MW, Inamura K, Farman AG (Eds).
CARS'99. Amsterdam: Elsevier (1999) 534-538.
Deutsches Krebsforschungszentrum, Abteilung Medizinische und Biologische Informatik,
Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
U.Engelmann@DKFZ-Heidelberg.de
Steinbeis-Transferzentrum Medizinische Informatik, Heidelberg, Germany
The CHILI ® software family started as a dedicated teleradiology system, known under the name MEDICUS [1] . The second generation teleradiology system CHILI has then been designed to match the teleradiology requirements of the ACR and the needs of the MEDICUS users [2] . The experience of software developers and teleradiology users of the first years of clinical use have been integrated into the new design which started in 1996 [3] . This paper describes the general system design and application areas.
CHILI is based on a software component architecture. Independent (and distributed) software components communicate by means of a middleware which has been realized as a message passing system. The main components are (see figure 1 ): Viewer, Message System, Database Service, Send and Receive Services, Import and Export Services, DICOM Server and Query Service. The Multiplexer manages connection requests and the automated starting of components in the CHILI system and between them . The components of the CHILI system can be distributed in the local network.
This overall design allows a very flexible configuration of the system
for specific environments. The different services and modules can be
combined in different ways to form custom solutions. Examples of
typical configurations (in clinical use) are:
The most powerful communication protocol for data exchange and the only one for teleconferencing is the CHILI protocol which includes a strong data security concept [4]. This includes all measures which are necessary to comply with German and European requirements and law.
It cannot be expected that all communication partners have the same teleradiology system. Thus, CHILI offers additional communication methods (see figure 2):
These transfer methods enable the CHILI user to send images nearly to everybody with access to a computer and a network. Drawbacks are that teleconferences are possible with the CHILI protocol only and that the user has to take reasonable precautions for data privacy and security when he does not use the secure CHILI protocol.
As users do always need more functionality than a system can provide, we designed the CHILI PlugIn mechanism [5]. Users can extend the system by powerful image postprocessing functions [6] or interfaces to other information systems. PlugIns can be either existing applications or new moduls with interfaces to the existing CHILI components (see figure 1). The developer is free in his choice of programming languages and interface toolkits (e.g. C, C++, Tcl/Tk).
The Java Virtual Machine [7] is a PlugIn itself. Thus, Java programs can be integrated and communicate with CHILI as well.
CHILI has been developed under the UNIX operating system in ANSI C. The most important reasons were portability, reliability and data security. The realized system is not dependent of vendor specific UNIX dialects or hardware features. The most economically priced and powerful system is a Personal Computer running the Linux operating system [8] .
CHILI clients are running under Microsoft Windows under the eXceed system (Hummingbird). The latter allows to run the original code and X Window based user interface. It offers the same functionality as the Unix client, inclusive teleconferences. A complete CHILI Classic is available under OpenNT, resp. Interix (Softway Systems, Inc.) with all components for data exchange and teleconferencing on Windows NT systems.
A Web Interface is the most hardware and operating system independent solution. The CHILI WWW Server is a frontend to the CHILI database. Users can access it with any web browser. The user interface is nearly the same as the standard CHILI Viewer. Data can be retrieved from CHILI databases or DICOM archives which are accessed through the CHILI database interface as well. The images can be displayed with 8 bit in JPEG format or DICOM encoded with the Java/DICOM viewer.
Over the time the system became a PACS component which can be used as an interface to DICOM compliant archives, for DICOM printing and reporting. Images can be distributed in-house and light weighted clients running on PCs can be used to view or process the images in teleconferences. Clients for MS Windows are available as well as web based interfaces which can be accessed from any hardware or operating system with a web browser. The CHILI database can be configured to act as a cache for the PACS archive. A storage hierarchy can be configured to reduce the traffic on the archive and to optimize image transfers on the network. The user has not to know where the data are actually stored.
The CHILI Viewer with the multi-head option and diagnostic monitors is suited for image reporting. The filmless radiology can be realized with this technology.
The future development will continue on the Java implementation of the complete CHILI architecture to offer the most flexible and hardware/software independent environment for PACS and teleradiology. The feedback and suggestions of the users influenced the system architecture by a great extent. The differences between PACS and teleradiology components will vanish.
Nearly 40 systems are currently running in clinical routine in Germany. More than 200 thousand images have been distributed between the communication partners in the last two years, proving the CHILI architecture as a powerful and flexible environment for PACS and teleradiology.
[1] Engelmann U, Schröter A, Baur U, Schroeder A, Werner O, Wolsiffer K, Baur HJ, Göransson B, Borälv E, HP: Teleradiology System MEDICUS. In: Lemke (Ed). CAR `96: Computer Assisted Radiology, 10th International Symposium and Exhibition, Paris. Amsterdam: Elsevier (1996) 537-542.
[2] Engelmann U. Schröter A, Baur U, Werner O, Schwab M, Müller H, Bahner M, Meinzer HP. Second Generation Teleradiology. In: Lemke HU, Vannier MW, Inamura K (eds): Computer Assisted Radiology and Surgery. Amsterdam: Elsevier (1997) 632-637.
[3] Bahner M L, Engelmann U. Meinzer H-P, van Kaick G. Design necessities for future teleradiology systems - Conclusion from a field test. Eur Radiol 7 (1997) S17.
[4] Baur HJ, Engelmann U, Saurbier F, Schröter A, Baur U, Meinzer HP. How to deal with Security and Privacy Issues in Teleradiology. Computer Methods and Programs in Biomedicine, 53, 1 (1997) 1-8.
[5] Engelmann U, Schröter A, Baur U, Schwab M, Werner O, Makabe MH, Meinzer HP. Openness in (Tele-) Radiology Workstations: The CHILI PlugIn Concept. In: Lemke HU, Vannier MW, Inamura K, Farman A (Eds). CAR'98 - Computer Assisted Radiology and Surgery. Amsterdam: Elsevier (1998) 437-442.
[6] Evers H, Mayer A, Engelmann U, Schröter A, Baur U, Wolsiffer K, Meinzer HP. Extending a Teleradiology System by Tools for 3D-Visualization and Volumetric Analysis. In Cesnik B, McCray AT, Scherrer JR (eds). MedInfo '98; 9th World Congress on Medical Informatics. Amsterdam: IOS Press (1998) 1033-1035.
[7] Flanagan D. Java in a Nutshell. Cambridge: O'Reilly 1996.
[8] Siever E. Linux in a Nutshell. Cambridge: O'Reilly 1999.