Uwe Engelmann

The Heidelberg ray tracing model

The Heidelberg ray tracing model, developed especially for visualization of medical images, is based on a global illumination model and contains a number of application-specific assumptions. It simulates the projection of a scene with well-defined lighting. A detailed description of the model follows an overview of existing and competing illumination procedures. >

Five-year experience with setup and implementation of an integrated database system for clinical documentation and research

In radiation oncology, where treatment concepts are elaborated in interdisciplinary collaborations, handling distributed, large heterogeneous amounts of data efficiently is very important, yet challenging, for an optimal treatment of the patient as well as for research itself. This becomes a strong focus, as we step into the era of modern personalized medicine, relying on various quantitative data information, thus involving the active contribution of multiple medical specialties. Hence, combining patient data from all involved information systems is inevitable for analyses. Therefore, we introduced a documentation and data management system integrated in the clinical environment for electronic data capture. We discuss our concept and five-year experience of a precise electronic documentation system, with special focus on the challenges we encountered. We specify how such a system can be designed and implemented to plan, tailor and conduct (multicenter) clinical trials, ultimately reaching the best clinical performance, and enhancing interdisciplinary and clinical research.

How to deal with security issues in teleradiology

The use of teleradiological systems for medical image communication is increasing significantly. Digital images can be transferred over public telephone (e.g. ISDN) lines to colleagues for interpretation and/or consultation. Thus, a new quality is being introduced into the process of radiological diagnostics. However, technical implementation of such systems is accompanied by little consideration of legal, i.e. data protection and security, issues. In this paper we describe a concept for data protection in teleradiology which unites aspects of privacy and security as well as user aspects. After highlighting the legal situation in Germany we describe the methodology used for deriving the security profile for teleradiology in Germany. As a result the set of security measures which have to be employed with a teleradiology system is listed. A detailed description follows of how the software requirements are implemented in the teleradiology software MEDICUS.

Virtual surgery in a (tele-)radiology framework

Presents telemedicine as an extension of a teleradiology framework through tools for virtual surgery. To classify the described methods and applications, the research field of virtual reality (VR) is broadly reviewed. Differences with respect to technical equipment, methodological requirements and areas of application are pointed out. VR, desktop VR and augmented reality are differentiated and discussed in some typical contexts of diagnostic support, surgical planning, therapeutic procedures, simulation and training. Visualization techniques are compared as a prerequisite for VR and assigned to distinct levels of immersion. The advantage of a hybrid visualization kernel is emphasized with respect to the desktop VR applications that are subsequently shown. Moreover, software design aspects are considered by outlining functional openness in the architecture of the host system. A teleradiology workstation was extended by dedicated tools for surgical planning through a plug-in mechanism. Examples of recent areas of application are introduced, such as liver tumor resection planning, diagnostic support in heart surgery, and craniofacial surgery planning. In the future, surgical planning systems will become more important. They will benefit from improvements in image acquisition and communication, new image processing approaches and techniques for data presentation. This will facilitate pre-operative planning and intra-operative applications.

A three-generation model for teleradiology

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.

An interactive system for volume segmentation in computer-assisted surgery

Computer-assisted surgery aims at a decreased surgical risk and a reduced recovery time of patients. However, its use is still limited to complex cases because of the high effort. It is often caused by the extensive medical image analysis. Especially, image segmentation requires a lot of manual work. Surgeons and radiologists are suffering from usability problems of many workstations. In this work, we present a dedicated workplace for interactive segmentation integratd within the CHILI (tele-)radiology system. The software comes with a lot of improvements with respect to its graphical user interface, the segmentation process and the segmentatin methods. We point out important software requirements and give insight into the concepts which were implemented. Further examples and applications illustrate the software system.

Mobile teleradiology: all images everywhere

This paper describes the ongoing work on mobile teleradiology systems in the EC-funded project MTM. The current development is based on the CHILI software architecture which provides a PACS and tel ...

The German teleradiology system MEDICUS system description and experiences in a German field test

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.

Extending a teleradiology system by tools for visualization and volumetric analysis through a plug-in mechanism

This paper describes ongoing research concerning interactive volume visualization coupled with tools for volumetric analysis. To establish an easy to use application, the three-dimensional-visualization has been embedded in a state of the art teleradiology system, where additional functionality is often desired beyond basic image transfer and management. Major clinical requirements for deriving spatial measures are covered by the tools, in order to realize extended diagnosis support and therapy planning. Introducing a general plug-in mechanism, this work exemplarily describes the useful extension of an approved application. Interactive visualization was achieved by a hybrid approach taking advantage of both the precise volume visualization based on the Heidelberg ray-tracing model and the graphics acceleration capabilities of modern workstations. Several tools for volumetric analysis extend the three-dimensional-viewing. They are controlled by adequate input devices to select locations in the data volume, measure anatomical structures or initiate a segmentation process. Moreover, a haptic interface can be connected to provide a more realistic feedback while navigating within the three-dimensional-reconstruction. The work is closely related to research in the field of heart, liver and head surgery. In cooperation with our medical partners the development of tools as presented facilitates the integration of image analysis into the clinical routine.

Implementing a full-feature PACS solution in accordance with the IHE technical framework: the CHILI approach.

RATIONALE AND OBJECTIVES During the last 4 years, Integrating the Healthcare Enterprise (IHE) has worked in establishing a reliable integrated environment for medical imaging devices and other clinical information systems by using existing industry standards such as Digital Imaging and Communication in Medicine (DICOM) and Health Level Seven (HL7). Because IHE is organized and driven by professional organizations representing both buyers and vendors, it was able to define a common language for the various health care parties who are involved in the integration process. Thus IHE offers a rigorously organized technical framework that provides a comprehensive guide for a coordinated implementation of information standards. MATERIALS AND METHODS A multistage plan for incorporating the IHE elements while scaling up general-purpose workstations with teleradiology functionalities to a full-feature picture archiving and communication system (PACS) solution was created. To introduce a pragmatic example, the plan approach was applied to the CHILI workstations (CHILI, Heidelberg, Germany). To implement the proposed plan in making various legacy systems comply with IHE, the effects of available resources and market needs on the plan are discussed. Most implementation challenges and problems were overcome using generic design approaches and well-designed DICOM utilities. RESULTS On completion of the first stage, the PACS viewer and reporting workstations were IHE-compliant. In addition, the plan facilitates the conformance process while maintaining the planned software development cycle. CONCLUSION Based on these positive results and the practical experience acquired during the first stage, further stages will be completed to provide the system with the required plug-and-play interoperability among systems from different vendors.