The U.S. Army Medical Command, lead by the Brooke Army Medical Center, has embarked on a futuristic project which will revolutionize the practice of radiology in the DoD. The U.S. Army Virtual Radiology Environment (USAVRE) is a CONUS-based network that connects all the Army's major medical centers and Regional Medical Commands (RMC). The purpose of the USAVRE is to improve the quality, access, and cost of radiology services in the Army via the use of state-of-the-art medical imaging, computer, and networking technologies. The USAVRE contains multimedia-viewing workstations for static and dynamic modality cases. The storage and archiving systems are based on a distributed computing environment using Common Object Request Broker Architecture (CORBA) middleware protocols. Collaboration between archive centers and viewing workstations are managed by CORBA functions and multimedia object streams. The underlying Telecommunications network is an ATM based backbone network that connects to the RMC regional networks and PACS local networks at medical centers and RMC clinics. The U.S. Army Information Systems Engineering Command (USAISEC) at Ft. Huachuca, AZ is responsible for the ATM backbone network to the RMC sites. The virtual Radiology services in a USAVRE must be applied to several radiology modalities in a virtual network environment. In this discussion, we assume the existence of several PACS networks within a USAVRE environment that have a need to exchange multimedia images and patient information. We define a multimedia collaborative distributed computing environment (DCE) in medical imaging and radiology as a collection of collaborating PACS networks with workstations and image archive systems for the purposes of acquiring and exchanging patient static and video sequence images; storage, retrieval, and archival of those images; performing image analysis and multimedia consultation on patient cases; operation and management of the network to optimize its resources; and to improve the quality and access of the radiology services to the patients. This paper describes the open systems architecture for the USAVRE, including the PACS and Global PACS user equipment. This project is a collaborative effort between military, university, and industry centers with expertise in Teleradiology and Global PACS applications.