A new needle-crystalline computed radiography detector.
The most successful digital radiography detectors to date have been storage phosphor plates used in computed radiography (CR). The detector is cheap, has good producibility, and is robust. Direct radiography (DR) systems are being developed based on flat-panel technology. Better image quality is claimed for some DR systems. On the other hand, DR detectors have low producibility and robustness, and a high price. A new CR detector is being developed at Agfa that combines the advantages of CR and DR. It is a storage phosphor plate made up of needle-shaped crystals. The phosphor efficiently converts absorbed x-ray quanta into photostimulable centers for efficient read out. It has a large dynamic range and its emission is efficiently detected with both photomultiplier tube (PMT) and charge coupled device (CCD). It is shown that CR systems based on the new detector offer image quality that matches that of the best DR systems. (+info)
Simulation of disaster recovery of a picture archiving and communications system using off-site hierarchal storage management.
The purpose of this communication is to report on the testing of the disaster recovery capability of our hierarchical storage management (HSM) system. Disaster recovery implementation is a requirement of every mission-critical information technology project. Picture archiving and communications systems (PACS) certainly falls into this category, even though the counterpart, conventional film archive, has no protection against fire, for example. We have implemented a method for hierarchical storage with wavelet technology that maximizes on-site case storage (using lossy compression), retains bit-preserved image data for legal purposes, provides an off-site backup (lossless bit-preserving wavelet transform), and provides for disaster recovery. Recovery from a natural (earthquake and subsequent fire) or technical (system crash and data loss) disaster was simulated by attempting to restore from the off-site image and database backup to clean core PACS components. The only existing loaded software was the operating system. The database application was reloaded locally, and then the database contents and image store were loaded from the off-site component of the HSM system. The following measurements were analyzed: (1) the ability to recover all data; (2) the integrity of the recovered database and image data; (3) the time to recover the database relative to the number of studies and age of the archive, as well as bandwidth between the local and remote site; and (4) the time to recover image data relative to compression ratio, number of studies, number of images, and time depth of the archive. This HSM system, which maximizes on-site storage, maintains a legal record, and provides off-site backup, also facilitates disaster recovery for a PACS. (+info)
"Permanent" records: experience with data migration in radiology information system and picture archiving and communication system replacement.
In the replacement of both a radiology information system (RIS) and a picture archiving and communication system (PACS) archive, data were migrated from the prior system to the new system. We report on the process, the time and resources required, and the fidelity of data transfer. We find that for two PACS archives, both organized according to the Digital Imaging and Communications in Medicine (DICOM) information model, data may be transferred with full fidelity, but the time required for transfer is significant. Transfer from off-line backup media was found to be faster than transfer from our robotic tape library. In contrast, the RIS replacement required extensive labor to translate prior data between dissimilar information models, and some data were inevitably lost in the translation. Standards for RIS information models are needed to promote the migration of data without loss of content. (+info)
Effects of a large-scale deployment of soft-copy devices for picture archiving and communication systems viewing.
A study was developed to investigate several aspects of deployment of stand-alone computers and a web-based server for displaying digital images. The costs associated with installation, upgrades, training, and maintenance of both systems were documented, as well as patterns of usage and preferences of physicians for the two types of systems. A clinical archive was created to store relevant images with a web-based front end. Users were classified according to their imaging requirements and were given access to images from either the diagnostic archive (full study sets) or the clinical archive. The range of functionality of the web-based system was significantly lower than that of the stand-alone system; however, the costs associated with the administration of the stand-alone systems were far higher than those associated with a web server. A clinical archive was created to store relevant images with a web-based front end. This study illustrates the different approaches to distribution of images to clinicians with the costs of administration of each system. (+info)
Associative memory hamiltonians for structure prediction without homology: alpha-helical proteins.
Energy landscape theory is used to obtain optimized energy functions for predicting protein structure, without using homology information. At short sequence separation the energy functions are associative memory Hamiltonians constructed from a database of folding patterns in nonhomologous proteins and at large separations they have the form of simple pair potentials. The lowest energy minima provide reasonably accurate tertiary structures even though no homologous proteins are included in the construction of the Hamiltonian. We also quantify the funnel-like nature of these energy functions by using free energy profiles obtained by the multiple histogram method. (+info)
A simple mechanism for sharing and transporting medical digital case information across disparate computer language and data storage environments.
It is challenging to remotely share generic medical case information without an agreed upon definition of a medical digital teaching file (DTF). By utilizing an application of the extensible markup language (XML) called web-distributed data exchange (WDDX) along with an agreed upon WDDX structure, it is technically easy to share or syndicate medical case DTFs across computing environments that use different information models and computer languages. Thus, this easily implemented technology offers us an immediately available means to share and increase the value of scientific knowledge. (+info)
Management of the picture archiving and communications system archive at Texas Children's Hospital.
As hospitals convert from conventional film-based imaging to picture archival and communications systems (PACS), methods for managing an enormous library of images must change considerably. While most hospitals are required to retain general, nonmammographic, radiologic images for 7 years beyond the examination date, our pediatric hospital must maintain images until the child's eighteenth birthday, plus the 5-year statute of limitations. Although the physical extent of an electronic archive is tiny compared with a film archive, a long-range strategy is required to ensure that electronic images acquired today can be retrieved and viewed 23 years in the future. Challenges to the long-term stability of the electronic archive include the limited and uncertain shelf life of high-density electronic storage media, the finite maintainability of the electromechanical systems for reading the media, the short product lifetime of software for accessing the images, rapid development of higher density storage products, and the exponential advancement of computer and networking technology that fuels product obsolescence. Since we cannot assure the function of our current archive in two decades, we are committed to a continual process of migration of old electronic image data to newer media and systems. As an early-adopter of PACS technology, Texas Children's Hospital's (TCH) archive management experience is relevant to others. Although not filled to capacity, our first digital archive, based on phase-change write-once-read-many (WORM) technology, was forced into an inactive status by software and hardware changes. Our second set of archives was partially filled with low-density magneto-optical disk (MOD) media, when the drives were upgraded to high density and then filled to capacity. This undesirable situation forced us into shelf management of media. Our third-generation archive is based on a helical tape library with the capacity to contain 7 years of examinations. We will describe the motivation for data migration, limitations in the methods available to perform the migration, and unanticipated benefits of the migration process. (+info)
Integrating digital educational content created and stored within disparate software environments: an extensible markup language (XML) solution in real-world use.
OBJECTIVE: To provide a standardized and scaleable mechanism for exchanging digital radiologic educational content between software systems that use disparate authoring, storage, and presentation technologies. MATERIALS/METHODS: Our institution uses two distinct software systems for creating educational content for radiology. Each system is used to create in-house educational content as well as commercial educational products. One system is an authoring and viewing application that facilitates the input and storage of hierarchical knowledge and associated imagery, and is capable of supporting a variety of entity relationships. This system is primarily used for the production and subsequent viewing of educational CD-ROMS. Another software system is primarily used for radiologic education on the world wide web. This system facilitates input and storage of interactive knowledge and associated imagery, delivering this content over the internet in a Socratic manner simulating in-person interaction with an expert. A subset of knowledge entities common to both systems was derived. An additional subset of knowledge entities that could be bidirectionally mapped via algorithmic transforms was also derived. An extensible markup language (XML) object model and associated lexicon were then created to represent these knowledge entities and their interactive behaviors. Forward-looking attention was exercised in the creation of the object model in order to facilitate straightforward future integration of other sources of educational content. XML generators and interpreters were written for both systems. RESULTS: Deriving the XML object model and lexicon was the most critical and time-consuming aspect of the project. The coding of the XML generators and interpreters required only a few hours for each environment. Subsequently, the transfer of hundreds of educational cases and thematic presentations between the systems can now be accomplished in a matter of minutes. The use of algorithmic transforms results in nearly 100% transfer of context as well as content, thus providing "presentation-ready" outcomes. CONCLUSION: The automation of knowledge exchange between dissimilar digital teaching environments magnifies the efforts of educators and enriches the learning experience for participants. XML is a powerful and useful mechanism for transfering educational content, as well as the context and interactive behaviors of such content, between disparate systems. (+info)