OSIRIX: An Open Source Platform for Advanced Multimodality Medical Imaging

The rapid evolution of digital imaging techniques and the increasing number of multidimensional and multimodality studies constitute a challenge for digital imaging workstations and image analysis programs. While Web-based solutions have emerged as simple ways for wide distribution of images they often lack the necessary tools for advanced image processing and 3D visualization. The increases in performance of personal computers allow implementing complex image processing and visualization tools on standard off-the-shelf hardware. OSIRIX is a fully interactive image navigation and visualization software was designed for display and analysis of large sets of three dimensional medical images. The program is specifically designed to handle new generations of multi-modality imaging data combining anatomical and metabolic images such as PET/CT. It also provides dynamic display for time-varying images such as cardiac motion or metabolic functional studies. Designed by a team of radiologists it provides an intuitive and user friendly user interface tailored for physicians that are not familiar with complex image processing and manipulation techniques. The OSIRIX software package runs as an independent application and handles its own image study database that is updated automatically when new images are downloaded. Images can be pushed from the PACS using a DICOM interface and can also be "pulled" by a DICOM query-retrieve function of the program. Image files can also be manually copied from off-line media or from other network sources. The visualization software provides all the basic image manipulation functions of zoom, pan, intensity adjustment, filtering with an incredibly fast realtime performance. Additional functions such as multiplanar reformatting, slice thickness adjustment, volume rendering are also accessible in real-time. The software allows loading very large sets of data instantaneously and allows for unlimited number of image series to be displayed simultaneously with all function of image display including fast cine loops available to all displayed image sets. In the software architecture that we adopted the number of images that can be handled simultaneously does not depend on the amount of memory available on the computer. Most of the display functions being handled by the optimized hardware-software combination of OpenGL that takes advantage of the hardware capability of the video card it does not rely on the computer RAM memory for preloading images. OSIRIX architecture allows seamless integration of multiple workstations and archive servers through peer-to-peer technology allowing image data to be shared across the network without the need of a central database or archive. A server version of OSIRIX Core Data database also allows to access distributed archives servers in the same way. The convenience and high performance of the system allows multiple users to share data more efficiently and perform advanced image processing and analysis in a distributed environment. It is particularly suitable for large hospitals and academic environments where clinical conferences, interdisciplinary discussions and successive sessions of image processing are often part of complex workflow or patient management and decision making. OSIRIX software is distributed free of charge as an open-source software under GNU licensing scheme. The program and its source code can be downloaded from: http://homepage.mac. com/rossetantoine/osirix/ .