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PubMed2004

Complete loss of ICD programmability after magnetic resonance imaging.

The purpose of this case report is to describe the effects of an MRI performed on a patient without realizing that an ICD has been previously implanted. After a few seconds of imaging the adversity was recognized and the examination was stopped immediately. The patient was not pacemaker dependent and had neither physical complaints nor electrocardiographic changes in the surface ECG. A consecutively performed ICD assessment showed a backup mode with standard parameters for pacing (VVI 50 beats/min) and arrhythmia detection and treatment. The device could not be programmed by the external programmer. With the exception of printing out the parameters, all software functions were no longer feasible. A device examination by the manufacturer after ICD replacement showed that a major portion of the device memory was corrupt. Even ICDs of a newer generation are susceptible to magnetic interference, with the danger of complete loss of programmability.

Brain↗
PubMed2005

Metal-free silicon-molecule-nanotube testbed and memory device.

Work from several laboratories has shown that metal nanofilaments cause problems in some molecular electronics testbeds. A new testbed for exploring the electrical properties of single molecules has been developed to eliminate the possibility of metal nanofilament formation and to ensure that molecular effects are measured. This metal-free system uses single-crystal silicon and single-walled carbon nanotubes as electrodes for the molecular monolayer. A direct Si-arylcarbon grafting method is used. Use of this structure with pi-conjugated organic molecules resulted in a hysteresis loop with current-voltage measurements that are useful for an electronic memory device. The memory is non-volatile for more than 3 days, non-destructive for more than 1,000 reading operations and capable of more than 1,000 write-erase cycles before device breakdown. Devices without pi-conjugated molecules (Si-H surface only) or with long-chain alkyl-bearing molecules produced no hysteresis, indicating that the observed memory effect is molecularly relevant.

Computer Storage Devices↗
PubMed2006

Digital video recording and archiving in ophthalmic surgery.

Currently most ophthalmic operating rooms are equipped with an analog video recording system [analog Charge Couple Device camera for video grabbing and a Video Cassette Recorder for recording)]. We discuss the various advantages of a digital video capture device, its archiving capabilities and our experience during the transition from analog to digital video recording and archiving. The basic terminology and concepts related to analog and digital video, along with the choice of hardware, software and formats for archiving are discussed.

Computer Storage Devices↗
PubMed2005

Exposure assessment for retrospective follow-up studies of semiconductor- and storage device-manufacturing workers.

OBJECTIVE: This exposure assessment was conducted in the first large study of mortality and cancer incidence in semiconductor and storage device manufacturing. METHODS: Unique combinations of division, department and job codes and names (DDJ) from work history records were assigned to work groups and exposure categories. Agent exposure matrices assessed differences in potential exposures between groups. Changes in exposure over time were tracked by dividing the production history into manufacturing eras. RESULTS: Nineteen work groups were developed to capture 310,351 unique DDJs from 1965-1999. Agent exposure matrices contrasted exposure potential to solvents, metals, and work in cleanrooms between groups, and three manufacturing eras were identified for each site. CONCLUSIONS: The work groups, manufacturing eras and agent matrices have been used to classify workers in the study of cancer incidence and mortality.

Computer Storage Devices↗
PubMed2003

Diagnostic value of onset-recordings and marker annotations in dual chamber pacemaker stored electrograms.

AIMS: Stored electrograms (EGM) have recently been introduced into pacemaker therapy. New generation devices offer the possibility to store the onset of the EGM (several seconds preceding storage trigger) and marker annotations. The aim of the study was to evaluate whether the diagnostic capabilities of EGMs are improved by these new features. METHODS: We studied 65 patients (age 68+/-12 years, 41 male) implanted with a DDDR-system (PulsarMax II 1280; Guidant). During a 1-month period 319 EGMs have been recorded. EGM triggers were: Ventricular Tachycardia (VT), Non-Sustained VT (NSVT), Atrial Tachycardia Response (ATR), Pacemaker Mediated Tachycardia (PMT) and Sudden Bradycardia Response (SBR). First, each EGM was analysed with onset and markers blinded. EGMs were classified with respect to their trigger as confirmed, not-confirmed or false-positive. Analysis was then repeated with markers visible but without onset, and thereafter vice versa. Finally, EGMs were analysed with both features. It was noted whether the presence of marker annotations and/or onset-recording changed the initial classification of the stored EGMs. RESULTS: 169 EGMs were triggered by SBR, which can only be confirmed with onset recording. False positive EGMs (atrial undersensing) occurred in 12%. The remaining 150 EGMs were triggered by ATR (80%), NSVT (11%), VT (6%) and by PMT (3%). Without onset/markers 37 of these 150 EGMs (25%) could not be confirmed. With markers and onset 33/37 (89%) of these EGMs could now be classified as confirmed or false positive. These EGMs became diagnostic with onset alone in 24%, with markers alone in 24%, and with the combination of both in 41%. In 4 EGMs no definite diagnosis could be established. CONCLUSION: Stored electrograms provide direct insights into device function, thereby providing a validation of diagnostic data. The expanded recording of onset and markers results in markedly improved diagnostic capabilities - compared with conventional EGMs. These new features were necessary to interpret correctly 61% of all stored electrograms, without which a diagnosis would not have been possible. Both onset-recording and marker annotation are necessary for optimal analysis.

Aged↗
PubMed2006

Cancer incidence among semiconductor and electronic storage device workers.

AIMS: To evaluate cancer incidence among workers at two facilities in the USA that made semiconductors and electronic storage devices. METHODS: 89 054 men and women employed by International Business Machines (IBM) were included in the study. We compared employees' incidence rates with general population rates and examined incidence patterns by facility, duration of employment, time since first employment, manufacturing era, potential for exposure to workplace environments other than offices and work activity. RESULTS: For employees at the semiconductor manufacturing facility, the standardised incidence ratio (SIR) for all cancers combined was 81 (1541 observed cases, 95% confidence interval (CI) 77 to 85) and for those at the storage device manufacturing facility the SIR was 87 (1319 observed cases, 95% CI 82 to 92). The subgroups of employees with > or =15 years since hiring and > or =5 years worked had 6-16% fewer total incidents than expected. SIRs were increased for several cancers in certain employee subgroups, but analyses of incidence patterns by potential exposure and by years spent and time since starting in specific work activities did not clearly indicate that the excesses were due to occupational exposure. CONCLUSIONS: This study did not provide strong or consistent evidence of causal associations with employment factors. Data on employees with long potential induction time and many years worked were limited. Further follow-up will allow a more informative analysis of cancer incidence that might be plausibly related to workplace exposures in the cohort.

Adult↗
PubMed2004

[The place of telemedicine in rhythmology and cardiac pacing].

Rapid advancement in telecommunication technology has made possible automatic periodic transmission of pacemaker and implantable defibrillator data to the attending physician (home monitoring). Furthermore, technology using remote control software allows, through device programmers, interrogation of the device memory, permitting remote monitoring by physicians or technical support of the manufacturer. Potential applications of these two capabilities include a close watch over the functioning of the devices, ability to obtain an earlier diagnosis (and management) of arrhythmic events, and assistance at the time of implant procedure and routine follow up. Finally these new tools raise several questions concerning safety aspects (including reliability of transmission, encrypted transfer, restricted access of the central database), economic aspects, and physician and manufacturer's liability.

Arrhythmias, Cardiac↗
PubMed1994

Microprocessor-based memory device for ambulatory heart rate and physical activity recording.

Using microprocessor techniques, a portable digital memory device has been designed for the ambulatory monitoring of heart rate and physical activity. The device consists of a microprocessor, an ECG amplifier to record the heart rate and an accelerometer to detect the physical activity. This accelerometer is piezo-resistive and is suitable for ambulatory physical activity recording, because this sensor requires low electrical power, has high durability and wide frequency response (DC approximately 1.2 kHz). Changes in heart rates and physical activity in daily life have been successfully recorded.

Computer Storage Devices↗
PubMed2004

The role of atomic scale investigation in the development of nanoscale materials for information storage applications.

It is well established that the response of devices based on the giant magnetoresistance (GMR) effect depends critically on film microstructure, with parameters such as interfacial abruptness, the roughness and waviness of the layers, and grain size being crucial. Such devices have applications in information storage systems, and are therefore of great technological interest as well as being of fundamental scientific interest. The layers must be studied at high spatial resolution if the microstructural parameters are to be characterized with sufficient detail to enable the effects of fabrication conditions on properties to be understood, and the techniques of high resolution electron microscopy, transmission electron microscopy chemical mapping, and atom probe microanalysis are ideally suited. This article describes the application of these techniques to a range of materials including spin valves, spin tunnel junctions, and GMR multilayers.

Alloys↗
PubMed2002

Pacemaker stored electrograms: teaching us what is really going on in our patients.

Stored electrograms (EGMs), well-known diagnostic tools in implantable cardioverter defibrillators, have now been incorporated in pacemakers as well, thereby increasing their diagnostic capabilities. The clinician can detect and diagnose patient arrhythmias with EGMs and directly validate diagnostic data stored by the devices. The appropriateness of detection algorithms can also be judged. Initial experiences with pacemaker EGMs reveals their potential to detect and diagnose sensing or detection algorithm problems. These so-called "false-positive" EGMs help to optimize pacemaker programming. Date and time stamp can correlate an event to patient symptoms. Recent advances, like onset recordings and marker annotation, have further increased the effectiveness of stored EGMs. The use of patient-triggered magnet-stored EGMs facilitates diagnostic workups in symptomatic pacemaker patients and reveals nondevice related symptoms in a considerable number of cases. Stored EGMs in pacemakers will soon be a standard diagnostic tool that can illustrate what is really going on in our patients.

Arrhythmias, Cardiac↗
PubMed2000

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.

Computer Storage Devices↗
PubMed2002

Radiation dosimetry using three-dimensional optical random access memories.

The ability to determine particle type and energy plays an important role in the dosimetry of heavy charged particles (HCP) and neutrons. A new approach to radiation dosimetry is presented, which is shown to be capable of particle type and energy discrimination. This method is based on utilising radiation induced changes in the digital information stored on three-dimensional optical random access memories (3D ORAM). 3D ORAM is a small cube (a few mm3) composed of poly(methyl methacrylate) doped with a photochromic dye. and it was originally proposed as a memory device in high speed parallel computers. A Nd:YAG laser system is used to write and read binary information (bits) on the ORAM, which functions as a charged particle detector. Both the read and the write processes use two laser beams that simultaneously strike the material to cause a colour change at their intersection (similar to the darkening of light-sensitive sunglasses when exposed to sunlight.) The laser produces colour changes in the ORAM, which then reverts to the original colour ('bit-flips') at sites where energy is deposited from interaction with incident HCP or neutron-recoil protons. The feasibility of this approach was demonstrated both theoretically and experimentally. Calculations based on track structure theory (TST) predict that when HCP interact with the ORAM material, the local energy deposition is capable of inducing measurable 'bit-flips'. These predictions were recently confirmed experimentally using two types of ORAM systems, one based on spirobenzopyran and the other on anthracene, as the photochromic dyes.

Computer Storage Devices↗
PubMed2002

Feasibility of a neutron detector-dosemeter based on single-event upsets in dynamic random-access memories.

The feasibility was investigated of a solid-state neutron detector/dosemeter based on single-event upset (SEU) effects in dynamic random-access memories (DRAMs), commonly used in computer memories. Such a device, which uses a neutron converter material to produce a charged particle capable of causing an upset, would be light-weight, low-power, and could be read simply by polling the memory for bit flips. It would have significant advantages over standard solid-state neutron dosemeters which require off-line processing for track etching and analysis. Previous efforts at developing an SEU neutron detector/dosemeter have suffered from poor response, which can be greatly enhanced by selecting a modern high-density DRAM chip for SEU sensitivity and by using a thin 10B film as a converter. Past attempts to use 10B were not successful because the average alpha particle energy was insufficient to penetrate to the sensitive region of the memory. This can be overcome by removing the surface passivation layer before depositing the 10B film or by implanting 10B directly into the chip. Previous experimental data show a 10(3) increase in neutron sensitivity by chips containing borosilicate glass, which could be used in an SEU detector. The results are presented of simulations showing that the absolute efficiency of an SEU neutron dosemeter can be increased by at least a factor of 1000 over earlier designs.

Computer Storage Devices↗
PubMed1998

Cine film replacement: digital archival requirements and remaining obstacles.

The acceptance of the Digital Imaging and Communication in Medicine (DICOM) standard and the Compact Disk-Recordable (CD-R) as the interchange medium have been critical developments for laboratories that need to move forward on the cine replacement front, while at the same time retain a means to communicate with other centers. One remaining essential component which has not been satisfactorily addressed is the issue of how digital image data should be archived within an institution. Every laboratory must consider the diverse issues which affect the choice of a digital archiving system. These factors include technical and economic issues, along with the clinical routines prevailing in their laboratory. A complete understanding of the issues will lead to the formulation of multiple options which may prove acceptable and will help to overcome the last obstacle which remains for the complete replacement of cine film in the cardiac catheterization laboratory.

Archives↗
PubMed2000

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.

Computer Storage Devices↗
PubMed1990

The impact of image storage organization on the effectiveness of PACS.

Picture archiving communication system (PACS) requires efficient handling of large amounts of data. Mass storage systems are cost effective but slow, while very fast systems, like frame buffers and parallel transfer disks, are expensive. The image traffic can be divided into inbound traffic generated by diagnostic modalities and outbound traffic into workstations. At the contact points with medical professionals, the responses must be fast. Archiving, on the other hand, can employ slower but less expensive storage systems, provided that the primary activities are not impeded. This article illustrates a segmentation architecture meeting these requirements based on a clearly defined PACS concept.

Computer Storage Devices↗
PubMed2001

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.

Computer Communication Networks↗