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PubMed2006

Comparison of LCD and CRT displays based on efficacy for digital mammography.

RATIONALE AND OBJECTIVES: To compare two display technologies, cathode ray tube (CRT) and liquid crystal display (LCD), in terms of diagnostic accuracy for several common clinical tasks in digital mammography. MATERIALS AND METHODS: Simulated masses and microcalcifications were inserted into normal digital mammograms to produce an image set of 400 images. Images were viewed on one CRT and one LCD medical-quality display device by five experienced breast-imaging radiologists who rated the images using a categorical rating paradigm. The observer data were analyzed to determine overall classification accuracy, overall lesion detection accuracy, and accuracy for four specific diagnostic tasks: detection of benign masses, malignant masses, and microcalcifications, and discrimination of benign and malignant masses. RESULTS: Radiologists had similar overall classification accuracy (LCD: 0.83 +/- 0.01, CRT: 0.82 +/- 0.01) and lesion detection accuracy (LCD: 0.87 +/- 0.01, CRT: 0.85 +/- 0.01) on both displays. The difference in accuracy between LCD and CRT for the detection of benign masses, malignant masses, and microcalcifications, and discrimination of benign and malignant masses was -0.019 +/- 0.009, 0.020 +/- 0.008, 0.012 +/- 0.013, and 0.0094 +/- 0.011, respectively. Overall, the two displays did not exhibit any statistically significant difference (P > .05). CONCLUSION: This study explored the suitability of two different soft-copy displays for the viewing of mammographic images. It found that LCD and CRT displays offer similar clinical utility for mammographic tasks.

Breast Neoplasms↗
PubMed2006

Behavioural responses to video playbacks by zebra finch males.

A major problem for communication research is to provide standardized stimuli and to disentangle the relative contribution of different sensory channels to the compound signal and its effectiveness. Video techniques have frequently been used for this purpose. Fifty Hertz cathode ray tube (CRT) screens cannot be used for birds because their flicker frequency is lower than the time resolution of at least songbirds. Thin film transistor (TFT) screens have successfully been used to present video clips of behaving conspecifics. We show here that they are indeed transmitting video images in a way that enables zebra finches to react appropriately to live video images of conspecifics and that the test birds are able to detect small differences in the behaviour of the stimulus animals. Adding acoustic information strongly enhanced the reaction to the video clips.

Animal Communication↗
PubMed2006

Image quality performance of liquid crystal display systems: influence of display resolution, magnification and window settings on contrast-detail detection.

The aim of this study was to investigate the combined effects of liquid crystal display (LCD) resolution, image magnification and window/level adjustment on the low-contrast performance in soft-copy image interpretation in digital radiography and digital mammography. In addition, the effect of a new LCD noise reduction mechanism on the low-contrast detectability was studied. Digital radiographs and mammograms of two dedicated contrast-detail phantoms (CDRAD 2.0 and CDMAM 3.4) were scored on five LCD devices with varying resolutions (1-3- and 5-megapixel) and one dedicated 5-megapixel cathode ray tube monitor. Two 5-megapixel LCDs were included. The first one was a standard 5-megapixel LCD and the second had a new (Per Pixel Uniformity) noise reduction mechanism. A multi-variate analysis of variance revealed a significant influence of LCD resolution, image magnification and window/level adjustment on the image quality performance assessed with both the CDRAD 2.0 and the CDMAM 3.4 phantoms. The interactive adjustment of brightness and contrast of digital images did not affect the reading time, whereas magnification to full resolution resulted in a significantly slower soft-copy interpretation. For digital radiography applications, a 3-megapixel LCD is comparable with a 5-megapixel CRT monitor in terms of low-contrast performance as well as in reading time. The use of a 2-megapixel LCD is only warranted when radiographs are analysed in full resolution and when using the interactive window/level adjustment. In digital mammography, a 5-megapixel monitor should be the first choice. In addition, the new PPU noise reduction system in the 5-megapixel LCD devices provides significantly better results for mammography reading as compared to a standard 5-magapixel LCD or CRT. If a 3-megapixel LCD is used in mammography setting, a very time-consuming magnification of the digital mammograms would be necessary.

Analysis of Variance↗
PubMed2005

Basal cell carcinoma and World War II-era cathode ray oscilloscope exposure.

BACKGROUND: There is a high prevalence of skin cancer in World War II servicemen stationed in the Pacific theater as a result of various risk factors such as exposure to ultraviolet radiation and genetic predisposition. OBJECTIVE: We sought to describe whether a possible association exists between basal cell carcinoma (BCC) development and the use of high-voltage cathode ray tube (CRT) oscilloscopes manufactured around 1940 to 1955, which were a source of X-radiation. METHODS: We present a case series of 9 men aged 65 to 93 years who presented with similar head and neck distributions of BCC and a history of extensive use of early CRT oscilloscopes during and shortly after the World War II era. The patients were interviewed and their medical records reviewed to determine CRT exposure times and BCC location, subtype, and treatment. Representative BCC histologic sections were reviewed. RESULTS: A total of 230 BCCs of the head and neck region were identified and mapped. Questionnaires determined a minimum exposure of 600 (range, 624-9600) hours within a 60-cm distance of early CRT screens in all patients. The average number of aggressive histologic subtypes was 23.5%. The average number of Mohs micrographic surgery layers required to obtain negative margins was 1.99 compared with 1.63 in the control group treated by the same Mohs micrographic surgeon (P < .002). CONCLUSION: This descriptive study is the first to suggest that ionizing radiation from early CRT oscilloscopes may be a factor in the development of multiple BCCs of the head and neck with increased subclinical spread.

Aged↗
PubMed2005

Grey-scale reversed radiographic display in the detection of approximal caries.

OBJECTIVES: Purpose of this study was to determine the influence of grey-scale reversal of digital radiographic images on the detection of proximal caries. METHODS: Five observers assessed digital bitewing radiographs (Sidexis((R)), Sirona) of 320 unrestored surfaces of extracted posterior teeth embedded in 20 models, simulating pairing of maxillary and mandibular arches, using a six-category caries rating scale. Images were displayed in normal [N] and inverse [IN] mode at different image sizes (display ratio: 1:1, 1:2, 1:7) on a cathode-ray tube monitor (Nokia 446 XS) and a TFT display (Panasonic LC 50 S). Validation standard was defined as histological lesion depth. Validity was expressed as areas under receiver operating characteristic curves (AUC) calculated for two levels of histological caries penetration: presence of caries and presence of a dentine lesion. The factors 'inverse display', 'image size on-screen' 'display type' and 'disease cut-off' were analysed by repeated measures ANOVA. RESULTS: Inverse image display significantly influenced the diagnostic validity (P=0.014), but a reduced accuracy was only seen at the lowest image size (AUC (SE): [N] 0.64 (0.02); [IN] 0.62 (0.02)). At the validation threshold 'dentine caries' approximal caries detection deteriorated when using grey-scale reversal (AUC (SE): [N] 0.71 (0.02); [IN] 0.69 (0.02)). CONCLUSIONS: In conclusion, grey-scale reversal of digital radiographs did not optimise approximal caries detection and aggravated the detectability of dentinal lesions.

Analysis of Variance↗
PubMed2006

An integrated impact assessment and weighting methodology: evaluation of the environmental consequences of computer display technology substitution.

Computer display technology is currently in a state of transition, as the traditional technology of cathode ray tubes is being replaced by liquid crystal display flat-panel technology. Technology substitution and process innovation require the evaluation of the trade-offs among environmental impact, cost, and engineering performance attributes. General impact assessment methodologies, decision analysis and management tools, and optimization methods commonly used in engineering cannot efficiently address the issues needed for such evaluation. The conventional Life Cycle Assessment (LCA) process often generates results that can be subject to multiple interpretations, although the advantages of the LCA concept and framework obtain wide recognition. In the present work, the LCA concept is integrated with Quality Function Deployment (QFD), a popular industrial quality management tool, which is used as the framework for the development of our integrated model. The problem of weighting is addressed by using pairwise comparison of stakeholder preferences. Thus, this paper presents a new integrated analytical approach, Integrated Industrial Ecology Function Deployment (I2-EFD), to assess the environmental behavior of alternative technologies in correlation with their performance and economic characteristics. Computer display technology is used as the case study to further develop our methodology through the modification and integration of various quality management tools (e.g., process mapping, prioritization matrix) and statistical methods (e.g., multi-attribute analysis, cluster analysis). Life cycle thinking provides the foundation for our methodology, as we utilize a published LCA report, which stopped at the characterization step, as our starting point. Further, we evaluate the validity and feasibility of our methodology by considering uncertainty and conducting sensitivity analysis.

Computer Terminals↗
PubMed2006

Estimation of future outflows and infrastructure needed to recycle personal computer systems in California.

The objectives of the present study are to estimate future quantities of electronic waste (e-waste) for which appropriate infrastructure needs to be established, and to the estimate the total cost for e-waste recycling in California. Estimation of the future amounts of e-waste as a function of time is critical to effective e-waste management. To generate estimates, we use a time-series materials flow analysis model (MFAM). The model estimates future e-waste quantities by modeling the stages of production, usage, and disposal. We consider four scenarios for the estimation of future e-waste generation in order to consider the effects of exportation outside the State of California and of user preferences to store or to recycle the e-waste. These efforts were further investigated through the use of sensitivity analysis. The results of the present research indicate that the outflow (recycling) amount of central processing units (CPUs) will increase and will reach approximately 8.5 million units per year in 2013, but the outflow (recycling) of cathode ray tube (CRT) monitors will decrease from 2004 in California because of the replacement of CRT monitors by liquid crystal display (LCD) monitors. In 2013, the cost for CPU recycling will be 1.7 times higher than that in 2005. But for CRT monitors, the cost for recycling in 2013 will be negligible. After the State of California enacted the ban on landfill disposal of e-waste, recycling became the most common end-of-life (EOL) option in California. Also, after 2005, the State of California will need more than 60 average-capacity materials recovery facilities (MRFs), to recycle the number of personal computer systems generated, which represents an investment in capital of over 16 million dollars.

California↗
PubMed2005

The pointillism method for creating stimuli suitable for use in computer-based visual contrast sensitivity testing.

An increasingly large corpus of clinical and experimental neuropsychological research has demonstrated the utility of measuring visual contrast sensitivity. Unfortunately, existing means of measuring contrast sensitivity can be prohibitively expensive, difficult to standardize, or lack reliability. Additionally, most existing tests do not allow full control over important characteristics, such as off-angle rotations, waveform, contrast, and spatial frequency. Ideally, researchers could manipulate characteristics and display stimuli in a computerized task designed to meet experimental needs. Thus far, 256-bit color limitation in standard cathode ray tube (CRT) monitors has been preclusive. To this end, the pointillism method (PM) was developed. Using MATLAB software, stimuli are created based on both mathematical and stochastic components, such that differences in regional luminance values of the gradient field closely approximate the desired contrast. This paper describes the method and examines its performance in sine and square-wave image sets from a range of contrast values. Results suggest the utility of the method for most experimental applications. Weaknesses in the current version, the need for validation and reliability studies, and considerations regarding applications are discussed. Syntax for the program is provided in an appendix, and a version of the program independent of MATLAB is available from the author.

Computer Graphics↗
PubMed2005

Visual masking in magnetic resonance imaging.

When a brief target picture is followed by another picture (mask), people often report that they are not consciously aware of the target. Thus, visual masking can be used to manipulate perceptual awareness of target pictures. To avoid interference with magnetic resonance imaging, pictures have been presented on liquid crystal device (LCD) and thin film transistor (TFT) projectors that were placed outside of the scanner room. However, we found that display devices with LCD/TFT technology exhibit poor accuracy in presenting pictures at brief durations [Wiens, S., Fransson, P., Dietrich, T., Lohmann, P., Ingvar, M., Ohman, A., 2004. Keeping it short: A comparison of methods for brief picture presentation. Psychological Science, 15, 282--285]. In this paper, we present a reliable and valid masking procedure involving two LCD/TFT projectors in combination with mechanical shutters. Because LCD/TFT projectors present pictures in steady state at longer durations (e.g., after 70 ms), picture presentation is more ecologically valid than for common cathode ray tube (CRT) monitors that present pictures in multiples of refresh cycles. Also, because picture presentation with mechanical shutters is instantaneous and reliable in terms of onset, rise time, and duration, shutters can be used to control picture durations precisely in steps of milliseconds. In this paper, we also discuss risks for confounding effects from unreliable picture presentations in masking. Our findings and arguments recommend the use of mechanical shutters in front of LCD/TFT projectors in imaging studies of visual masking.

Humans↗
PubMed1998

Telemedicine in practice.

Telemedicine is defined as the "delivery of health care and sharing of medical knowledge over a distance using telecommunication systems." The concept of telemedicine is not new. Beyond the use of the telephone, there were numerous attempts to develop telemedicine programs in the 1960s mostly based on interactive television. The early experience was conceptionally encouraging but suffered inadequate technology. With a few notable exceptions such as the telemetry of medical data in the space program, there was very little advancement of telemedicine in the 1970s and 1980s. Interest in telemedicine has exploded in the 1990s with the development of medical devices suited to capturing images and other data in digital electronic form and the development and installation of high speed, high bandwidth telecommunication systems around the world. Clinical applications of telemedicine are now found in virtually every specialty. Teleradiology is the most common application followed by cardiology, dermatology, psychiatry, emergency medicine, home health care, pathology, and oncology. The technological basis and the practical issues are highly variable from one clinical application to another. Teleradiology, including telenuclear medicine, is one of the more well-defined telemedicine services. Techniques have been developed for the acquisition and digitization of images, image compression, image transmission, and image interpretation. The American College of Radiology has promulgated standards for teleradiology, including the requirement for the use of high resolution 2000 x 2000 pixel workstations for the interpretation of plain films. Other elements of the standard address image annotation, patient confidentiality, workstation functionality, cathode ray tube brightness, and image compression. Teleradiology systems are now widely deployed in clinical practice. Applications include providing service from larger to smaller institutions, coverage of outpatient clinics, imaging centers, and nursing homes. Teleradiology is also being used in international applications. Unresolved issues in telemedicine include licensure, the development of standards, reimbursement for services, patient confidentiality, and telecommunications infrastructure and cost. A number of states and medical boards have instituted policies and regulations to prevent physicians who are not licensed in the respective state to provide telemedicine services. This is a major impediment to the delivery of telemedicine between states. Telemedicine, including teleradiology, is here to stay and is changing the practice of medicine dramatically. National and international communications networks are being created that enable the sharing of information and knowledge at a distance. Technological barriers are being overcome leaving organizational, legal, financial, and special interest issues as the major impediments to the further development of telemedicine and realization of its benefits.

Computer Communication Networks↗
PubMedDate not supplied

Characteristics of hyperacuity sensitivity in normal and cyclovertical deviation subjects.

PURPOSE: To compare the sensitivity of hyperacuity of patients with cyclovertical deviation with that of subjects with normal vision. METHODS: The sensitivity of hyperacuity was measured in 42 volunteers with normal vision and in 12 patients with cyclovertical deviation, using a newly developed computerized device that randomly presents two opposing targets at vertical or at horizontal directions on the cathode ray tube display. RESULTS: In subjects with normal vision, higher sensitivity was obtained when the targets were aligned in either a vertical or a horizontal direction. These highly sensitive ranges were defined as "the neutral zone of hyperacuity." An anisotropy of the sensitivity of hyperacuity was observed in these subjects, ie, better sensitivity was obtained when the displacement was away from the neutral zone, whereas worse sensitivity was obtained when the displacement was close to the neutral zones. In the patients with cyclovertical deviation, the sensitivity of hyperacuity was low around the neutral zones, which may confirm the dysfunction of the central nervous system. CONCLUSION: This analytical method may be useful to investigate the pathophysiology of patients with cyclovertical deviations.

Adolescent↗
PubMedDate not supplied

Effects of stimulus blocking, light scattering, and distortion on multifocal electroretinogram.

PURPOSE: To investigate how the multifocal electroretinogram (ERG) is altered in conditions of blocking, light scattering, or distortion of the stimulus that are seen in ocular pathologies. METHODS: A central 40 degree-diameter stimulus pattern consisting of 61 hexagons was presented on a cathode ray tube monitor at a rate of 75 Hz according to the pseudo-random binary M sequence by the Veris computer program. Localized responses corresponding to each hexagon and ERG topographies were displayed on the computer screen. Central scotoma was simulated by blocking the central area of the stimulus, visual field constriction by blocking the outer area of the stimulus, mild cataract by using acrylic filters that caused light scatter, and epiretinal membrane by using a wavy plastic plate that produced metamorphopsia. RESULTS: The responses from the blocked area were nonrecordable whether blockage was central or peripheral; responses from the adjacent unblocked area had a larger amplitude when large areas of the stimulus were blocked. The light scatter that decreased vision from 20/20 to 20/70 did not significantly decrease response amplitudes. Responses from areas in which the stimulus pattern was distorted were minimally affected. CONCLUSIONS: The results show that the system records local ERGs from the macula and outside the macula. It can detect the area where the stimulus is blocked. Moderate light scattering and distortion do not cause loss of local ERG characteristics.

Adult↗
PubMed2001

Characterization and use of a digital light projector for vision research.

For creating stimuli in the laboratory, digital light projection (DLP) technology has the potential to overcome the low output luminance, lack of pixel independence, and limited chromaticity gamut of the cathode ray tube (CRT). We built a DLP-based stimulator for projecting patterns on the in vitro primate retina. The DLP produces high light levels and has good contrast. Spatial performance was similar to that of a CRT. Temporal performance was limited by the refresh rate (63 Hz). The chromatic gamut was modestly larger than that of a CRT although the primary spectra varied to a small degree with light output and numerical aperture.

Analog-Digital Conversion↗
PubMed2001

The performance of general-purpose colour CRT monitors in PACS environment.

General-purpose colour cathode ray tube (CRT) monitors are used commonly for image display in personal computer-based picture archiving and communication system (PACS) and telemedicine systems. At present, however, we have not enough information about their performance or reliability for this task. Therefore, we studied the performance of five general-purpose colour CRTs and the changes in their performance in a year. Resolution was measured visually using original digital images. Maximum and minimum luminances were measured at the centre and periphery of the CRTs. Distortion was measured in the centre and periphery using original digital images. All the monitors met their specifications. The inhomogeneity of luminance exceeded 20% and varied across the CRTs. Darker monitors took more time to reach stable luminance levels. The corner brightness seemed to be a good estimator of both performance and distortion in colour monitors.

Humans↗
PubMed2003

Dealing with electronic waste: modeling the costs and environmental benefits of computer monitor disposal.

The importance of information technology to the world economy has brought about a surge in demand for electronic equipment. With rapid technological change, a growing fraction of the increasing stock of many types of electronics becomes obsolete each year. We model the costs and benefits of policies to manage 'e-waste' by focusing on a large component of the electronic waste stream-computer monitors-and the environmental concerns associated with disposal of the lead embodied in cathode ray tubes (CRTs) used in most monitors. We find that the benefits of avoiding health effects associated with CRT disposal appear far outweighed by the costs for a wide range of policies. For the stock of monitors disposed of in the United States in 1998, we find that policies restricting or banning some popular disposal options would increase disposal costs from about US dollar 1 per monitor to between US dollars 3 and US dollars 20 per monitor. Policies to promote a modest amount of recycling of monitor parts, including lead, can be less expensive. In all cases, however, the costs of the policies exceed the value of the avoided health effects of CRT disposal.

Conservation of Natural Resources↗
PubMed2000

Management of scrap computer recycling in Taiwan.

It is estimated that approximately 300,000 scrap personal computers are generated each year in Taiwan [S.-L. Chang, A Study on the Scrap Computer Treatment Cost, Environment Protection Administration of Taiwan, December 1998 (in Chinese)]. The disposal of such a huge number of scrap computers presents a difficult task for the island due to the scarcity of landfills and incineration facilities available locally. Also, the hazardous materials contained (i.e., phosphor coatings of cathode ray tubes (CRTs), batteries, polychlorinated biphenyl capacitors, mercury-containing parts, liquid crystal display, high-lead content CRT funnel glass, and plastic containing flame-retardant bromine, etc.) in the scrap computers may seriously pollute the environment if they are not properly disposed of. Therefore, the EPA of Taiwan declared scrap personal computers the producer's recycling responsibility as of July 1997. Under this decree, the manufacturers, importers and sellers of personal computers have to properly recover and recycle the scrapped computers which they originally sell. On June 1, 1998, a producer responsibility recycling program for scrap computers was officially implemented in Taiwan. Under this program, consumers can bring their unwanted personal computers to the designated collection points and receive reward money. Currently, only six computer items are mandated to be recycled in this recycling program. They are notebooks, monitors, hard disks, power supplies, printed circuit boards and main frame shells. This article outlines the current scrap computer recycling system in Taiwan.

Bromine↗
PubMed1999

Assessment of potential macular function using a color saturation discrimination test in eyes with cataract.

PURPOSE: To study the efficacy of a color saturation discrimination test (CSDT) in assessing potential macular function in eyes with cataract. SETTING: Yamanashi Medical University and Nirasaki City Hospital, Yamanashi, Japan. METHODS: In this prospective study of 200 consecutive eyes with cataract, the thresholds of color saturation discrimination on 6 hues were measured with the CSDT. The CSDT program was run on a personal computer and cathode-ray tube color monitor. The preoperative CSDT scores and postoperative visual acuities were compared. In addition, preoperative laser interferometry (LI) and postoperative CSDT were performed on selected patients and the results compared with their preoperative CSDT results. RESULTS: Patients who had a CSDT score of 11 or more had a significantly lower postoperative visual acuity (P < .0001). The prevalence of neuroretinal abnormality postoperatively increased with the preoperative CSDT score. The CSDT score was not correlated with preoperative visual acuity (P = 1409). Cataract severity had little influence on the CSDT score. The preoperative results of the CSDT and Ll were correlated with the postoperative acuity, with the correlation coefficient being stronger with the CSDT (r = -0.338 and 0.276 for CSDT and Ll, respectively). CONCLUSION: The CSDT was effective in evaluating neuroretinal pathology and predicting postoperative acuity.

Cataract↗
PubMedDate not supplied

Doppler echocardiography in the human fetus.

Fetal echocardiography has allowed prenatal diagnosis of heart disease to become a reality over the last decade. Recently, pulsed Doppler flow studies have been applied to the examination of the fetal cardiovascular system. In fetuses with dysrhythmias, complex structural heart malformations, nonimmune hydrops fetalis, or mothers receiving nonsteroidal prostaglandin synthetase inhibitors, pulsed Doppler echocardiographic studies are clinically indicated. These studies involve noninvestigational tests that provide information of critical clinical import. These studies may occasionally, require energy intensities that exceed the 510(k) limits. The physician should be held responsible for educating patients to the potential risks versus benefits of any imaging study they undergo, but appending potentially alarming labels to transducers, machines, or cathode-ray tube displays can only serve to undermine the fabric of the physician-patient relationship without achieving the desired goal of protection of the patient.

Echocardiography, Doppler↗