Application Protocol for a DICOM Real Time Collaborative System Abdala, D. D., Prusse, M., Regert, A. G., Wangenheim, A. v. February 2006 {caju, martin, germano, awangenh}@inf.ufsc.br The Cyclops Project Laboratory of Telemedicine (LAB TELEMED) Computer Science and Statistics Department (INE) Universidade Federal de Santa Catarina (UFSC) Florianópolis – Santa Catarina – Brazil Phone: +55 48 3331-9516 Fax: +55 48 331-39516 Abstract This work presents a new generic application protocol for DICOM conformant medical collaborative systems. It implements simple techniques for data flow and encapsulation between two or more clients and a single server, using an extension of the DICOM Communication Layer within a server or a client as a session manager. The protocol was tested working over two image viewer clients remotely distributed and the synchronization level shows that collaborative systems can be executed in real time. 1. Introduction It is becoming increasingly common to use Digital Imaging and Communications in Medicine – DICOM [1] – compliant software and equipment in healthcare institutions, mostly Picture Archiving Communication Systems – PACS – to retrieve, store and transmit patient-related information. In major medical centers, teleconferences have also become routine, enabling specialist physicians to employ their time more efficiently. However, the technology commonly used was not developed with this specific purpose in mind (i.e. videoconference stream using standard definition television does not seem to be the best way to analyze a magnetic resonance image and confirm findings). In this sense, video conferencing is an efficient but limited system, only providing actuation on the exam in the client viewer where it is being shot and being extremely limited in image resolution and accuracy. To circumvent this issue, a direct shared view of the image information in scope on the teleconference would be the ideal way to manipulate it, and thus enable actions on both ends of the line to be carried out. This would provide a collaborative system scenario with real time interaction. Unfortunately, the direct share view of medical imaging data can not be achieved using only the protocol services provided by the DICOM standard, since it is not concerned in application specific requirements. Commercial solutions available for this purpose have proprietary protocols, making difficult the intercommunication between different software. Provide a new application protocol at the same time, simple to use and implement, to work embedded in DICOM compliant applications and light enough to do not impose prohibitive network bandwidth constraints is the main reason of the presented work. The protocol described in this paper aims the real time data application information sharing, where the exchange of application states, image data, presentation states video streams and synchronization between hosts can be achieved with no changing in the DICOM network services. 2. Problem Description Imagine that a difficult exam must be examined by a physician and the one in charge feels that he is not capable to give a final word. It is ethical to say that in such cases another physician must be consulted in aid to his fellow, since a diagnosis must be precise. These specialists can not meet each other so easily, so the final diagnosis must be delayed. Using a computer tool that works in a collaborative way, both physicians can quickly be in a virtual meeting and discuss the case as soon as possible, aiding considerably to speed up the process. The application protocol that we present here is intended to aid medical image viewers to be put easily to work together. This