VirtualPACS--a federating gateway to access remote image data resources over the grid.

Collaborations in biomedical research and clinical studies require that data, software, and computational resources be shared between geographically distant institutions. In radiology, there is a related issue of sharing remote DICOM data over the Internet. This paper focuses on the problem of federating multiple image data resources such that clients can interact with them as if they are stored in a centralized PACS. We present a toolkit, called VirtualPACS, to support this functionality. Using the toolkit, users can perform standard DICOM operations (query, retrieve, and submit) across distributed image databases. The key features of the toolkit are: (1) VirtualPACS makes it easy to use existing DICOM client applications for data access; (2) it can easily be incorporated into an imaging workflow as a DICOM source; (3) using VirtualPACS, heterogeneous collections of DICOM sources are exposed to clients through a uniform interface and common data model; and (4) DICOM image databases without DICOM messaging can be accessed.

Sharing data and analytical resources securely in a biomedical research Grid environment.

OBJECTIVES: To develop a security infrastructure to support controlled and secure access to data and analytical resources in a biomedical research Grid environment, while facilitating resource sharing among collaborators. DESIGN: A Grid security infrastructure, called Grid Authentication and Authorization with Reliably Distributed Services (GAARDS), is developed as a key architecture component of the NCI-funded cancer Biomedical Informatics Grid (caBIG). The GAARDS is designed to support in a distributed environment 1) efficient provisioning and federation of user identities and credentials; 2) group-based access control support with which resource providers can enforce policies based on community accepted groups and local groups; and 3) management of a trust fabric so that policies can be enforced based on required levels of assurance. MEASUREMENTS: GAARDS is implemented as a suite of Grid services and administrative tools. It provides three core services: Dorian for management and federation of user identities, Grid Trust Service for maintaining and provisioning a federated trust fabric within the Grid environment, and Grid Grouper for enforcing authorization policies based on both local and Grid-level groups. RESULTS: The GAARDS infrastructure is available as a stand-alone system and as a component of the caGrid infrastructure. More information about GAARDS can be accessed at http://www.cagrid.org. CONCLUSIONS: GAARDS provides a comprehensive system to address the security challenges associated with environments in which resources may be located at different sites, requests to access the resources may cross institutional boundaries, and user credentials are created, managed, revoked dynamically in a de-centralized manner.

Computerized pathological image analysis for neuroblastoma prognosis.

We present a pathological image analysis system for the computer-aided prognosis of neuroblastoma, a childhood cancer. The image analysis system automatically classifies Schwannian stromal development of pathological tissues and determines the grade of differentiation. Due to the demanding computational cost of processing large digitized slides, the system was implemented on a cluster of computers with automated load balancing within a multi-resolution framework. In our experiments, the overall accuracies for stromal classification and the grade of differentiation were 96.6% and 95.3%, respectively. Additionally, the multi-resolution framework reduced the run time of the single resolution approach by 53% and 34% on average for stromal classification and grade of differentiation, respectively. For these two cases, parallelization on a 16-node cluster reduced the sequential run time by 92% and 88% on average. Accuracy and efficiency of these techniques are promising for the development a computer-assisted neuroblastoma prognosis system.