Luís S. Ribeiro

Dicoogle - an open source peer-to-peer PACS.

Picture Archiving and Communication Systems (PACS) have been widely deployed in healthcare institutions, and they now constitute a normal commodity for practitioners. However, its installation, maintenance, and utilization are still a burden due to their heavy structures, typically supported by centralized computational solutions. In this paper, we present Dicoogle, a PACS archive supported by a document-based indexing system and by peer-to-peer (P2P) protocols. Replacing the traditional database storage (RDBMS) by a documental organization permits gathering and indexing data from file-based repositories, which allows searching the archive through free text queries. As a direct result of this strategy, more information can be extracted from medical imaging repositories, which clearly increases flexibility when compared with current query and retrieval DICOM services. The inclusion of P2P features allows PACS internetworking without the need for a central management framework. Moreover, Dicoogle is easy to install, manage, and use, and it maintains full interoperability with standard DICOM services.

XDS-I Outsourcing Proxy: Ensuring Confidentiality While Preserving Interoperability

The interoperability of services and the sharing of health data have been a continuous goal for health professionals, patients, institutions, and policy makers. However, several issues have been hindering this goal, such as incompatible implementations of standards (e.g., HL7, DICOM), multiple ontologies, and security constraints. Cross-enterprise document sharing (XDS) workflows were proposed by Integrating the Healthcare Enterprise (IHE) to address current limitations in exchanging clinical data among organizations. To ensure data protection, XDS actors must be placed in trustworthy domains, which are normally inside such institutions. However, due to rapidly growing IT requirements, the outsourcing of resources in the Cloud is becoming very appealing. This paper presents a software proxy that enables the outsourcing of XDS architectural parts while preserving the interoperability, confidentiality, and searchability of clinical information. A key component in our architecture is a new searchable encryption (SE) scheme-Posterior Playfair Searchable Encryption (PPSE)-which, besides keeping the same confidentiality levels of the stored data, hides the search patterns to the adversary, bringing improvements when compared to the remaining practical state-of-the-art SE schemes.

Clustering of distinct PACS archives using a cooperative peer-to-peer network

To face the demanding requirements of the clinical environment, PACS archives need to be resilient and reliable, supporting high availability and fault tolerance. Often, to ensure no data loss, PACS archives retain two copies of images on separate physical machines, using distributed data storage facilities. However, PACS do not take advantage of the various replicas to improve the transfer rates of medical images. This happens mostly because the DICOM standard does not comply with distributed fetching of image fragments while performing a store. Inspired by this unexplored opportunity, we designed and implemented a new solution that takes advantage of the distributed image replicas and, at the same time, respects the DICOM standard. Our strategy brought significant improvements in the exchange rates, load balancing and availability of installed PACS archives. Moreover, the adopted strategy forms a cluster of PACS archives that transparently enables horizontal scaling, facilitates the creation of backups, and gives to healthcare professionals a unified view of the distributed repositories.

A Centralized Platform for Geo-Distributed PACS Management

Picture Archive and Communication System (PACS) is a globally adopted concept and plays a fundamental role in patient care flow within healthcare institutions. However, the deployment of medical imaging repositories over multiple sites still brings several practical challenges namely related to operation and management (O&M). This paper describes a Web-based centralized console that provides remote monitoring, testing, and management over multiple geo-distributed PACS. The system allows the PACS administrator to define any kind of service or operation, reducing the need for local technicians and providing a 24/7 monitoring solution.

Current Trends in Archiving and Transmission of Medical Images

ion allowing access to infrastructure resources (e.g. storage, computation, server, data center) on-demand and paid according to the required quality-of-service (QoS). • Platform layer: Known as Platform as a Service (PaaS) extends the IaaS layer by hiding the IaaS complexity. PaaS is accessed as one big system and not by accessing individual virtual machines. Therefore, it provides an abstraction where the virtual machines are automatically managed by the cloud service provider. Offering reliable services by default such as storage, databases and signalization. • Application layer: Layer usually entitled as Software as a Service (SaaS) where the applications hosted on the Cloud are deployed on local computers typically through web-browser. On this layer, the payment is associated with the application itself and not with the platform or infrastructure below it. Typically, this layer is where developers build their applications. The services themselves have long been referred to as Software as a Service (SaaS) and Cloud does not change that (Michael Armbrust, 2009). Nevertheless, Cloud Computing allows the application providers the choice of deploying their product as SaaS without providing a data center.

A Proxy of DICOM services

Diagnostic tools supported by digital medical images have increasingly become an essential aid to medical decisions. However, despite its growing importance, Picture Archiving and Communication Systems (PACS) are typically oriented to support a single healthcare institution, and the sharing of medical data across institutions is still a difficult process. This paper describes a proposal to publish and control Digital Imaging Communications in Medicine (DICOM) services in a wide domain composed of several healthcare institutions. The system creates virtual bridges between intranets enabling the exchange, search and store of the medical data within the wide domain. The service provider publishes the DICOM services following a token-based strategy. The token advertisements are public and known by all system users. However, access to the DICOM service is controlled through a role association between an access key and the service. Furthermore, in medical diagnoses, time is a crucial factor. Therefore, our system is a turnkey solution, capable of exchanging medical data across firewalls and Network Address Translation (NAT), avoiding bureaucratic issues with local network security. Security is also an important concern - in any transmission across different domains, data is encrypted by Transport Layer Security (TLS).

Normalizing medical imaging archives for dose quality assurance and productivity auditing

Quality assurance for planned radiation exposure situations (e.g. x-ray, CT) requires the application of examination-specific scans tailored to patient age or size, body region and clinical indication for ensuring that the dose to each patient is as low as reasonably achievable for the clinical purpose of the image acquisition. Nevertheless, assuring quality implies a heavy manual labor to measure and optimize care services flow. There are already several methodologies and protocols that can be used to achieve this objective. However, the continuous monitoring of quality indicators is still not performed in many healthcare centers. The challenge is to find a way to analyze these metrics in an efficient, effective and convenient manner. Moreover, these results are not often shared, due to confidentiality and privacy of patients and medical staff. In this paper, we propose a methodology and a software tool to aggregate and normalize the monitoring data from distinct points, in order to collect indicators, namely about productivity, efficiency and dose usage, factors that are crucial for benchmarking and for improving the quality of protocol procedures. To evaluate the effectiveness of our solution, several results were collected from two medical institutions.

A framework for integration of heterogeneous medical imaging networks.

Medical imaging is increasing its importance in matters of medical diagnosis and in treatment support. Much is due to computers that have revolutionized medical imaging not only in acquisition process but also in the way it is visualized, stored, exchanged and managed. Picture Archiving and Communication Systems (PACS) is an example of how medical imaging takes advantage of computers. To solve problems of interoperability of PACS and medical imaging equipment, the Digital Imaging and Communications in Medicine (DICOM) standard was defined and widely implemented in current solutions. More recently, the need to exchange medical data between distinct institutions resulted in Integrating the Healthcare Enterprise (IHE) initiative that contains a content profile especially conceived for medical imaging exchange: Cross Enterprise Document Sharing for imaging (XDS-i). Moreover, due to application requirements, many solutions developed private networks to support their services. For instance, some applications support enhanced query and retrieve over DICOM objects metadata. This paper proposes anintegration framework to medical imaging networks that provides protocols interoperability and data federation services. It is an extensible plugin system that supports standard approaches (DICOM and XDS-I), but is also capable of supporting private protocols. The framework is being used in the Dicoogle Open Source PACS.

On demand IHE XDS document registries on the cloud

Purpose At our institute we organized a teaching environment enabling radiology and radioanatomy courses with today’s advanced 2D image reviewing and 3D image postprocessing to offer a state of the art environment to our Radiological Technologists in training, providing tools like MPR and VR [1]. Enabling students to handle large image sets remotely at home and during hands on courses. The advent of CT volume scanning did dramatically change our habit of image viewing and image postprocessing for our Radiological Technologists in training. Methods The original setup was created to support the teaching of the students at the medical faculty of the Vrije Universiteit Brussel. We agreed to share infrastructure of the teaching environment to the Hogeschool-Universiteit Brussel in order to enhance the skillslab setup. The vast amount of datasets originating from a clinical PACS are the building blocks for the educational anatomy and radiopathology training sets [2]. The image repository consists out of sufficient blinded image material. Native DICOM sets can be processed into MPR and VR sets. Teaching the Radiological Technologists takes place in skillslab at Hogeschool-Universiteit Brussel. The general purpose computers available in the skillslab are used as reviewing and processing stations. The courses on radiology and radioanatomy need to compete with other courses regarding the software installation. To avoid technical issues around compatibility of certain competing software and releases of products, we decided to apply a virtual environment. In this way we can freeze the correct software computer setting for our application without compromising the functionality of the other competing courses and vice versa. In the skillslab the students were dedicated to an individual client workstation during the practical lessons. On this client the student need to load and startup the prepared virtual machine from the server to start his learning session. At the Vrije Universiteit Brussel the general purpose thin clients classrooms were connected to a VMware server environment based on VMware Vsphere and VMware View software. The infrastructure is managed by the medical informatics department at the University College. Secondly the advanced setup was secured in order to provide teaching sets in reach over the internet for use at home [3]. Since hosting takes place on a central server, the hardware requirements of the remote client are minimal. The student had to install the VMWare client which runs on all latest versions of Windows, Mac and Linux platforms. This provides the students with a remote view on the virtual desktop; the communication between the client and the virtual desktops is based upon a secure remote desktop viewing protocol. With this approach the student is free to utilize his preferred computer system. By means of a standard internet connection the cases are available for analysis and processing at any time and at any place during their training. Results The teaching methods of the past where merely based on static presentation of images in text books and X-ray film based illustrations presented on lightboxes. In the interim period between film based, atlas viewing and the full digital system we did hand over the educational cases to the students on CD-R or DVD-R media, pointless to say that the production of those media were time-consuming and the access of these media was not very user friendly for the student. The profound change of teaching methods from plain atlas and hardcopy viewing to 3D sets was a difficult transition for some lecturers. After that transition period the lecturers were all convinced of the broader possibilities of the tools which enhanced the knowledge acquirements and improved abilities of image handling. Students embrace the possibilities of image processing and the possibilities to study their cases at their own speed and time. The 3D visualization did improve the understanding of complex anatomy training. The grades improved in field of anatomy and radiopathology Conclusions Without changing the infrastructure of our skillslab we were able to offer multiple applications such as advanced radiological viewing and image postprocessing. Once the infrastructure was tested and fully functional, the main job of the support team was on the server side. An upgrade of the iSite enterprise software will take place in the near future, which implies building a new virtual machine. When the virtual machine is fully tested, this environment can be redistributed in the computer classrooms. In an educational environment where possibly conflicting requirements in setup exist, this approach is highly appreciated by the teachers of different disciplines. The quality of our education program by means of the enhanced visualization is not only superior to the use of books and distributed CD-R, but is also more appreciated by the students. The ease of installation at the remote site and the possibility of use at home is certainly an added value for the students. The proposed system is nowadays an added value for students and lecturers. It will be part of the future teaching platform. We aim to extent its content and develop it into a base for our e-learning program. References [1] Silén, C., Wirell, S., Kvist, J., Nylander, E., & Smedby, O. (2008, Jun 30). Advanced 3D visualisation in student-centered medical education. Med Teach, pp. 115–124. [2] Turmezei, T., Tam, M., & Loughna, S. (2009, Sept 22). A survey of medical students on the impact of a new digital imaging library in the dissection room. Clin Anat, pp. 761–769. [3] Petersson, H., Sinkvist, D., Wang, C., & Smedby, O. (2009, Mar-Apr 2). Web-based interactive 3D visualization as a tool for improved anatomy learning. Anat Sci Educ, pp. 61– 68.

Leveraging XDS-I and PIX workflows for validating cross-enterprise patient identity linkage

Document exchange communities set the ground for cross-organization cooperation. They enable the exchange of patients documents across distinct health organizations. However, there are various challenges that must be overcame before deploying such communities, for instance the construction of the Enterprise Master Patient Index (EMPI) which maps the several patient identifiers of each domain. This paper describes the development of an interoperable distributed system that expedites the exchange of documents by taking care of the patient identities autonomously. The system automatically builds the EMPI leveraging the healthcare workflow (based on PIX and XDS-I) for validating the automatic linkages of the patient identifiers. The human validation is a consequence of users interaction with cross-domain documents: distributing and attenuating the validation effort.