Distributed architecture for image archival in a hospital-wide PACS

摘要

A hospital-wide PACS project is currently under development at the University Hospital of Geneva. This system is based on an open architecture regrouping equipment from multiple vendors in a distributed topology. The image archival is organized in multiple locations geographically distributed in the hospital. These regional archives are logically linked together to provide a virtual access to all images generated from different imaging modalities. A standardized image storage format called PAPYRUS was designed based on ACR-NEMA definitions to unify the image storage and display functionalities. The PACS database is also fully integrated with the concurrent RIS and HIS. Images from different archive servers are hierarchically distributed to other temporary storage space on regional display servers. Clusters of workstations are regrouped around these local servers allowing a more efficient access to the images on local subnetworks. Special software tools were designed for the management of image distribution and maintenance of local storage space. In addition to pre-programmed and rule-based distribution of images to regional display servers, special requests can be posted by the users to initiate the transfer of additional image files from the archive servers to their local display server. The design and implementation of the system will be presented and methodological issues will be discussed. Results from preliminary simulations performed prior to the final implementation will be presented and compared to real measurements performed on the system in operation. The advantages and difficulties of implementing a distributed hierarchical storage of images will be reported.