Finding the optimal picture archiving and communication system (PACS) architecture: a comparison of three PACS designs.
(9/96)
PURPOSE: At present, there are two basic picture archiving and communication system (PACS) architectures: centralized with a central cache and controller, and distributed with a distributed cache and central controller. A third architecture proposed here is an autonomous one with a distributed cache and no controller. This report will investigate the performance (as measured be central processing unit [CPU] and network load, scalability, and examination retrieval and display latency) of these three types. METHODS: The distributed PACS architecture will be simulated using an IMPAX R3.5 (AGFA, Ridgefield Park, NJ) PACS, while the centralized design will be simulated using an IMPAX R4 (AGFA) PACS. The autonomous system will be designed and implemented in-house. The autonomous system consists of two types of entities: basic components such as acquisition gateways, display stations, and long-term archives, and registry servers, which store global state information about the individual PACS components. The key feature of the autonomous system will be the replacement of the central PACS controller by the registry servers. In this scenario the registry servers monitor the interactions between the components, but do not directly govern them. Instead each component will contain the application logic it requires and will use the state information from the registry servers to take the appropriate action, such as routing images, prefetching studies, and expiring images from near line cache. In addition the routing of examinations will be optimized to reduce the duplication of image data. Display stations will be categorized by specialty (neuroradiology, pediatrics, chest, etc) and will retrieve studies for display on demand from intermediate servers dedicated to the corresponding specialty. Studies will be routed only to the intermediate servers and not to display stations. RESULTS: By distributing the application logic, an autonomous PACS architecture can provide increased fault tolerance and therefore increased uptime. In addition, the lack of a central controller and the use of intermediate servers improve the scalability of the system, as well as reduce CPU and network loads. (+info)
Use of keyboards and symptoms in the neck and arm: evidence from a national survey.
(10/96)
The objective of this study was to examine the relationship between upper limb symptoms and keyboard use in a population survey. A questionnaire was mailed to 21,201 subjects aged 16-64 years, selected at random from the registers of 34 British general practices. Information was collected on occupation and on regular use of keyboards (for >4 h in an average working day), pain in the upper limbs and neck, numbness or tingling in the upper limbs, headaches, and feelings of tiredness or stress. Associations were explored by logistic regression, with the resultant odds ratios converted into prevalence ratios (PRs). Among 12,262 respondents, 4899 held non-manual occupations. These included 1871 regular users of keyboards (e.g. computer operators, data processors, clerks, administrators, secretaries and typists). Pain in the neck or upper limbs and sensory symptoms were common in the non-manual workers overall (with 1 week period prevalences of 30 and 15%, respectively), and were associated with older age, smoking, headaches and tiredness or stress. After adjustment for these factors, regular keyboard use was significantly associated with pain in the past week in the shoulders (PRs 1.2-1.4) and the wrists or hands (PR 1.4), but not with elbow pain or sensory symptoms over the same period, or with neck or upper limb pain that prevented normal activities in the past year. Disabling symptoms were somewhat less prevalent among symptomatic keyboard users than among other symptomatic workers. We conclude that use of keyboards was associated with discomfort at the shoulder and wrist or hand, but risk estimates were lower than generally reported in workplace surveys. Previous estimates of risk in the occupational setting may have been biased by shared expectations, concerns, or other aspects of illness behaviour. (+info)
Managing predefined templates and macros for a departmental speech recognition system using common software.
(11/96)
The authors have developed a networked database system to create, store, and manage predefined radiology report definitions. This was prompted by complete departmental conversion to a computer speech recognition system (SRS) for clinical reporting. The software complements and extends the capabilities of the SRS, and 2 systems are integrated by means of a simple text file format and import/export functions within each program. This report describes the functional requirements, design considerations, and implementation details of the structured report management software. The database and its interface are designed to allow all radiologists and division managers to define and update template structures relevant to their practice areas. Two key conceptual extensions supported by the template management system are the addition of a template type construct and allowing individual radiologists to dynamically share common organ system or modality-specific templates. In addition, the template manager software enables specifying predefined report structures that can be triggered at the time of dictation from printed lists of barcodes. Initial experience using the program in a regional, multisite, academic radiology practice has been positive. (+info)
Evaluation of a flat CRT monitor for use in radiology.
(12/96)
Medical radiographs based on familiar projection techniques are planar images traditionally displayed by placing on a flat surface viewbox. Presenting these planar images in digital form on a traditional monitor with a curved surface may cause distortions, possibly affecting diagnoses. This would be true especially if physical linear dimensions of the anatomy are important. Reflections from ambient lights behind the observer also could be a problem with curved displays. The goal of this study was to compare physical and psychophysical performance of a flat-surface display monitor with a traditional curved-surface monitor. Two display monitors with different types of front glass-panel surfaces were evaluated. The first monitor had a traditional curved surface, and the other had a flat surface. Physical measurements included dynamic range, display function, veiling glare, and spatial uniformity. An observer performance study used low-contrast, square-wave patterns to determine just-noticeable differences. Ambient lights were turned off in one condition and on in the other. Physical measurements showed that the display functions were nearly identical, but uniformity, veiling glare, and signal-to-noise-ratio were better for the curved monitor. Observer performance was better overall with the curved monitor, but the degradation in performance between lights off and lights on was greater for the curved than flat monitor. The greater degradation with the lights on could be attributed to more reflections off the curved than the flat monitor. A flat-surface display monitor may be useful for viewing clinical radiographs. (+info)
Introduction of handheld computing to a family practice residency program.
(13/96)
BACKGROUND: Handheld computers are valuable practice tools. It is important for residency programs to introduce their trainees and faculty to this technology. This article describes a formal strategy to introduce handheld computing to a family practice residency program. METHODS: Objectives were selected for the handheld computer training program that reflected skills physicians would find useful in practice. TRGpro handheld computers preloaded with a suite of medical reference programs, a medical calculator, and a database program were supplied to participants. Training consisted of four 1-hour modules each with a written evaluation quiz. Participants completed a self-assessment questionnaire after the program to determine their ability to meet each objective. RESULTS: Sixty of the 62 participants successfully completed the training program. The mean composite score on quizzes was 36 of 40 (90%), with no significant differences by level of residency training. The mean self-ratings of participants across all objectives was 3.31 of 4.00. Third-year residents had higher mean self-ratings than others (mean of group, 3.62). Participants were very comfortable with practical skills, such as using drug reference software, and less comfortable with theory, such as knowing the different types of handheld computers available. CONCLUSION: Structured training is a successful strategy for introducing handheld computing to a residency program. (+info)
Evaluation of a new handheld biosensor for point-of-care testing of whole blood beta-hydroxybutyrate concentration.
(14/96)
OBJECTIVES: To evaluate performance characteristics of the newly available handheld combined glucose and ketone meter for beta-hydroxybutyrate measurement. DESIGN: Laboratory method evaluation. MAIN OUTCOME MEASURES: Accuracy of beta-hydroxybutyrate measurement and effect of acetoacetate interference at clinically important beta-hydroxybutyrate levels. RESULTS: Deming regression analysis of beta-hydroxybutyrate measurements assessed by the ketone sensor and a laboratory enzymatic method revealed a coefficient of determination of 0.989 (P<0.001). Passing-Bablok regression analysis showed a linear relationship between the two methods, ie Y= -0.32+1.13X. The 95% confidence interval of the slope and y-intercept were: slope=1.13 (95% confidence interval, 1.04 to 1.22); intercept= -0.32 (95% confidence interval, -0.59 to -0.06). The Bland-Altman plot showed a small proportional bias between the two methods. The mean bias +/-2 standard deviations was between -0.53 and 0.67 mmol/L. Beta-hydroxybutyrate measurements made by the sensor were linear up to 6 mmol/L. Replicate analysis of two samples spiked with 3.6 mmol/L and 0.8 mmol/L of beta-hydroxybutyrate resulted in coefficients of variation of 3.3% and 13%, respectively. The presence of acetoacetate caused a negative interference in beta-hydroxybutyrate measurement. Beta-hydroxybutyrate recovery was 97.0% and 90.7% when the ketone body ratios were 6:1 and 3:1, respectively. CONCLUSION: The analytical performance of the sensor, when operated according to manufacturer's instructions, could meet the needs of point-of-care beta-hydroxybutyrate measurement. Additional clinical studies are needed to assess the benefits of introducing such an assay in a clinical setting. (+info)
Cell and organ printing 1: protein and cell printers.
(15/96)
We have developed several devices for positioning organic molecules, molecular aggregates, cells, and single-cell organisms onto solid supports. These printers can create stable, functional protein arrays using an inexpensive technology. The cell printer allows us to create cell libraries as well as cellular assemblies that mimic their respective position in organs. The printers are derived from commercially available ink-jet printers that are modified to dispense protein or cell solutions instead of ink. We describe here the modifications to the print heads, and the printer hardware and software that enabled us to adapt the ink-jet printers for the manufacture of cell and protein arrays. The printers have the advantage of being fully automated and computer controlled, and allow for the high-throughput manufacture of protein and cell arrays. (+info)
Cell and organ printing 2: fusion of cell aggregates in three-dimensional gels.
(16/96)
We recently developed a cell printer (Wilson and Boland, 2003) that enables us to place cells in positions that mimic their respective positions in organs. However, this technology was limited to the printing of two-dimensional (2D) tissue constructs. Here we describe the use of thermosensitive gels to generate sequential layers for cell printing. The ability to drop cells on previously printed successive layers provides a real opportunity for the realization of three-dimensional (3D) organ printing. Organ printing will allow us to print complex 3D organs with computer-controlled, exact placing of different cell types, by a process that can be completed in several minutes. To demonstrate the feasibility of this novel technology, we showed that cell aggregates can be placed in the sequential layers of 3D gels close enough for fusion to occur. We estimated the optimum minimal thickness of the gel that can be reproducibly generated by dropping the liquid at room temperature onto a heated substrate. Then we generated cell aggregates with the corresponding (to the minimal thickness of the gel) size to ensure a direct contact between printed cell aggregates during sequential printing cycles. Finally, we demonstrated that these closely-placed cell aggregates could fuse in two types of thermosensitive 3D gels. Taken together, these data strongly support the feasibility of the proposed novel organ-printing technology. (+info)