Walid Gabriel Tohme

Digital mammography: tradeoffs between 50- and 100-micron pixel size

Improvements in mammography equipment related to a decrease in pixel size of digital mammography detectors raise questions of the possible effects of these new detectors. Mathematical modeling suggested that the benefits of moving from 100 to 50 micron detectors were slight and might not justify the cost of these new units. Experiments comparing screen film mammography, a storage phosphor 100 micron digital detector, a 50 micron digital breast spot device, 100 micron film digitization and 50 micron film digitization suggests that object conspicuity should be better for digital compared to conventional systems, but that there seemed to be minimal advantage to going from 100 to 50 microns. The 50 micron pixel system appears to provide a slight advantage in object contrast and perhaps in shape definition, but did not allow smaller objects to be detected.

The Evolution of Distributed Diagnosis: Teleradiology As a Case Study

As the limits of the healthcare enterprise expand so is the need to provide diagnoses across boundaries and disciplines. The definition of the healthcare enterprise has grown in such a way to encompass the diagnoses of images within individual hospital department to the sharing of images across the globe. From a single hospital the healthcare enterprise expands to a multi-center environment eventually creating the concept of the virtual healthcare enterprise where regardless of geographical boundaries and local site technical characteristics, sharing of patient information is possible. Based on a National Library of Medicine effort, this paper uses teleradiology as a case study to explore the concept of the expanding healthcare enterprise and identifies the technical issues associated with image sharing especially as they relate to middleware considerations including access control in a federated environment with grid computing as an enabling architecture

Comparing the security risks of paper-based and computerized patient record systems

How should hospital administrators compare the security risks of paper-based and computerized patient record systems. There is a general tendency to assume that because computer networks potentially provide broad access to hospital archives, computerized patient records are less secure than paper records and increase the risk of breaches of patient confidentiality. This assumption is ill-founded on two grounds. Reasons exist to say that the computerized patient record provides better access to patient information while enhancing overall information system security. A range of options with different trade-offs between access and security exist in both paper-based and computerized records management systems. The relative accessibility and security of any particular patient record management system depends, therefore, on administrative choice, not simply on the intrinsic features of paper or computerized information management systems.

Effects of motion-JPEG compression on the diagnostic quality of pediatric echocardiograms

Congenital heart disease is infrequent and often is apparent in the immediate newborn period. Accurate diagnosis delivered in real-time or near-real-time is important to provide appropriate care to avoid patient morbidity and mortality. Color-flow Doppler echocardiograms are an essential part of the diagnostic assessment of the newborn, however, few hospitals have the staff to interpret these studies appropriately. Transmission of these studies to a regional center with subspecialists will allow interpretation of the studies by physicians with expertise in this subspecialty. Transmission of these studies to a regional center with subspecialists will allow interpretation of the studies by physicians to appropriately and rapidly triage neonates with high-risk congenital heart disease. To make a teleradiology service affordable in the near future, the 73 million bit per second transmission speed must be reduced to affordable bandwidths using compression. The purpose of this study is to evaluate the impact of motion JPEG on the diagnostic quality of pediatric echocardiograms.

3D volume visualization in remote radiation treatment planning

This paper reports a novel applications of 3D visualization in an ARPA-funded remote radiation treatment planning (RTP) experiment, utilizing supercomputer 3D volumetric modeling power and NASA ACTS (Advanced Communication Technology Satellite) communication bandwidths at the Ka-band range. The objective of radiation treatment is to deliver a tumorcidal dose of radiation to a tumor volume while minimizing doses to surrounding normal tissues. High performance graphics computers are required to allow physicians to view a 3D anatomy, specify proposed radiation beams, and evaluate the dose distribution around the tumor. Supercomputing power is needed to compute and even optimize dose distribution according to pre-specified requirements. High speed communications offer possibilities for sharing scarce and expensive computing resources (e.g., hardware, software, personnel, etc.) as well as medical expertise for 3D treatment planning among hospitals. This paper provides initial technical insights into the feasibility of such resource sharing. The overall deployment of the RTP experiment, visualization procedures, and parallel volume rendering in support of remote interactive 3D volume visualization will be described.

Technology assessment for an integrated PC-based platform for three telemedicine applications

This paper investigates the design and technical efficacy of an integrated PC based platform for three different medical applications. The technical efficacy of such a telemedicine platform has not been evaluated in the literature and optimal technical requirements have not been developed. The first application, with the Department of Surgery, Division of Urology, tests the utility of a telemedicine platform including radiology images for a surgical stone disease consultation service from an off site location in West Virginia. The second application, with the Department of Internal Medicine, Division of Clinical Pharmacology, investigates the usefulness of telemedicine when used for a clinical pharmacology consultation service from an off-site location. The third application, with the Department of Pediatrics, will test telemedicine for trauma care triage service first within an off-site location in Virginia and then from there to Georgetown University Medical Center.

Design of a multimedia PC-based telemedicine network for the Monitoring of Renal Dialysis Patients

This paper investigates the design and implementation of a multimedia telemedicine application being undertaken by the Imaging Science and Information Systems Center of the Department of Radiology and the Division of Nephrology of the Department of Medicine at the Georgetown University Medical Center (GUMC). The Renal Dialysis Patient Monitoring network links GUMC, a remote outpatient dialysis clinic, and a nephrologists home. The primary functions of the network are to provide telemedicine services to renal dialysis patients, to create, manage, transfer and use electronic health data, and to provide decision support and information services for physicians, nurses and health care workers. The technical parameters for designing and implementing such a network are discussed.

Protecting clinical data in PACS, teleradiology systems, and research environments

As clinical data is more widely stored in electronic patient record management systems and transmitted over the Internet and telephone lines, it becomes more accessible and therefore more useful, but also more vulnerable. Computer systems such as PACS, telemedicine applications, and medical research networks must protect against accidental or deliberate modification, disclosure, and violation of patient confidentiality in order to be viable. Conventional wisdom in the medical field and among lawmakers legislating the use of electronic medical records suggests that, although it may improve access to information, an electronic medical record cannot be as secure as a traditional paper record. This is not the case. Information security is a well-developed field in the computer and communications industry. If medical information systems, such as PACS, telemedicine applications, and research networks, properly apply information security techniques, they can ensure the accuracy and confidentiality of their patient information and even improve the security of their data over a traditional paper record. This paper will elaborate on some of these techniques and discuss how they can be applied to medical information systems. The following systems will be used as examples for the analysis: a research laboratory at Georgetown University Medical Center, the Deployable Radiology system installed to support the US Armys peace- keeping operation in Bosnia, a kidney dialysis telemedicine system in Washington, D.C., and various experiences with implementing and integrating PACS.

Evaluating the role of gigabit speed wide-area networks in remote medical treatment

This paper assesses the utility of gigabit speed wide-area networks such as the ACTS (Advanced Communication Technology Satellite) in enabling the delivery of medical expertise and service to remote regions, providing radiation treatment planning with access to supercomputers, and conducting workload redistribution. The first part of this multi- institutional effort between the University of Hawaii, Georgetown University Medical Center (GUMC) and the Ohio Supercomputer Center (OSC) uses a T1-VSAT (very small aperture terminal) for transmitting teleradiology images. The second part of the project uses high data rate (HDR) communications through the ACTS satellite at OC-3 transmission speeds (155 Mbps). This allows 3-D volume rendering of radiation therapy planning images between GUMC and OSC as well as the transmission of high-volume teleradiology loads between Tripler Army Medical Center (TAMC) and GUMC. It is shown that while the bandwidth required to perform 3D interactive radiation treatment planning is around 300 Mbps, OC-3 rates can be adequate. Another important application is workload redistribution either for hospitals that need to reroute a certain percentage of their workload to other institutions of the same magnitude but with different subspecialties or for peak workload leveling. This paper shows that gigabit speed wide area networks such as the ACTS-HDR network are required in order to achieve effective remote treatment planning as well as high volume teleradiology for workload redistribution.

Project RavenCare: global multimedia telemedicine in Alaska

Project RavenCare is a testbed for assessing the utility of teleradiology, telemedicine and electronic patient records systems for delivering health care to Native Alaskans in remote villages. It is being established as a joint project between the department of radiology at Georgetown University Medical Center and the Southeast Alaska Regional Health Corporation (SEARHC) in Sitka, Alaska. This initiative will establish a sustained routine clinical multimedia telemedicine support for a village clinic in Hoonah, Alaska and a regional hospital in Sitka. It will link the village clinic in Hoonah to Mt. Edgecumbe Hospital in Sitka. This regional hospital will in turn be linked to Georgetown University Hospital through the T1- VSAT (very small aperture terminal) of the NASA-ACTS (Advanced Communication Technology Satellite). Regional physicians in Hoonah lack support in providing relatively routine care in areas such as radiology and pathology. This project is an initial step in a general plan to upgrade telecommunications in the health care system of the Southeast Alaska region and will address aspects of two problems; limited communication between the village health clinics and the hospital and lack of subspecialty support for hospital-based physicians in Sitka.