Regular Screen Research Articles

Computer screen photo-excited surface plasmon resonance imaging

Angle and spectra resolved surface plasmon resonance (SPR) images of gold and silver thin films with protein deposits is demonstrated using a regular computer screen as light source and a web camera as detector. The screen provides multiple-angle illumination, p-polarized light and controlled spectral radiances to excite surface plasmons in a Kretchmann configuration. A model of the SPR reflectances incorporating the particularities of the source and detector explain the observed signals and the generation of distinctive SPR landscapes is demonstrated. The sensitivity and resolution of the method, determined in air and solution, are 0.145 nm pixel −1, 0.523 nm, 5.13 × 10 −3 RIU degree −1 and 6.014 × 10 −4 RIU, respectively, encouraging results at this proof of concept stage and considering the ubiquity of the instrumentation.

Automatic optimization of experimental conditions for fast evaluation of diagnostic tests using ubiquitous instrumentation

Abstract Rapid quantitative determinations of creatinine, potassium and glucose, all important parameters in routine medical diagnostics, are demonstrated using a computer screen photo-assisted technique (CSPT). CSPT uses regular computer screens as light sources and web cameras as imaging detectors for supporting optical evaluations of diverse character. The ubiquity and versatility of the setup, makes CSPT an attractive candidate for point of care determinations. A robust procedure for the automatic selection of experimental conditions in CSPT evaluation, including camera channels and illuminating colors that minimize the measuring time up to 5 times is described. The method utilizes the correlation between experimental conditions and classification scores, obtained under a generic 50 color training session, to extract measuring sequences as short as 9 s. The extracted measuring conditions automatically adapted to the different tests provided a general, practical and fast approach for CSPT optimization in real scenarios.

SU‐FF‐I‐71: Measurement of the 2‐D Modulation Transfer Function for Screen‐Film Magnification Mammography

Purpose: High resolution and contrast are very important for the detection of micro‐ calcifications and tumor masses in mammography screening. A very good measure of contrast versus resolution is the Modulation Transfer Function (MTF). In this study, we performed the measurement of the 2‐dimensional (2‐D) point spread function (PSP) and determined the 2‐D MTF for regular and magnification screen film mammography. Method and Materials: The experimental set up consists of the mammography machine, a pinhole camera mounted on test stand and the screen‐film cassette. The pinhole camera has circular aperture (10 μm diameter) in a lead disk. The pinhole camera was carefully aligned with the vertical line under the x‐ray tube focal spot. We used a Molybdenum anode/ Molybdenum filter x‐ray tube with a nominal focal spot size of 0.3 mm. We exposed the film‐screen using 30 kVp and 10 mAs exposure settings. The exposed films were processed and scanned using a transmission scanner with 4,800 × 4,800 dpi resolution to obtain the PSF. The PSF was processed with 2‐D Fourier transform to obtain the 2‐D MTF. Results: The obtained PSF was a double Gaussian function of space at high magnification (2.5) and was closer to a single Gaussian at low magnification (1.15). The spatial resolution in the image plane in all directions was observed to decrease with increasing magnification. The image resolution was focal spot limited as expected. However, the variation of limiting resolution with magnification did not exactly fit the theoretical expectation. Conclusion: We have successfully measured the 2‐D PSF and the 2‐D MTF for a screen film mammography in regular and magnification modes. While magnification provides a magnified view of a small part of the breast it has a lower limiting resolution due to the focal spot blurring and may compromise the detection of micro calcifications.

Ceramic scintillator-coupled linear array PIN photodiode for X-ray scanner

In order to design the full system of dual-energy X-ray scanner, each component of the system has been fabricated and tested. The high-energy X-ray detector modules used a ceramic scintillator of Eu 3+-doped (Gd,Y) 2O 3, manufactured using Glycine Nitrate Process (GNP). This was coupled to a 16-channel linear array PIN-type photodiode. The low-energy module was a commercially available Lanex Regular screen that was also coupled to a 16-channel linear array PIN-type photodiode. The 16-channel linear array PIN-type photodiode of 1.5 mm×3.2 mm was fabricated in the process of Electronics and Telecommunications Research Institute (ETRI). With a data acquisition system, signal-to-noise ratio was measured at low X-ray energy and low photon flux to evaluate each scintillator-coupled detector module. Through the experiment results and analysis, we inspected each component of the system as a dual-energy single-exposure X-ray scanner.

Telehealth Screen for Depression in A Chronic Illness Care Management Program

Chronic illness accounts for the majority of healthcare expenditures in the United States. Innovative telemedicine programs have been developed to help lessen the chronic illness burden, yet few have been developed to address comorbidity. Programs accommodating comorbidity are needed because most older adults suffer from two or more chronic illnesses. One of the most common and serious comorbidities in chronic illness is major depression, which has been shown to exacerbate morbidity, mortality, and cost. This study presents data on a telephone-based interactive voice recording (IVR) home monitoring program that was expanded to include quarterly screens for depression using the Patient Health Questionnaire (PHQ). Patients in an ongoing telehealth heart failure program were administered the PHQ-2 and PHQ-9 in November 2005 (Round 1) and February 2006 (Round 2). Patients were informed about the screen beforehand and an emergency protocol was established. At both screens, more than 90% of the patients completed the screen. Approximately 30% of the patients endorsed one of the PHQ-2 items in both rounds. Patients endorsing either of the PHQ-2 items then completed the full PHQ-9. Nurse care-managers contacted those scoring above the threshold of 10 on the PHQ-9 indicating possible depression. One patient expressed suicidality and was appropriately assessed for safety. There was no indication that patients were less likely to complete the screen in Round 2, although their average depression scores were slightly lower when compared with Round 1. A regular telephonic IVR screen for depression can be integrated into a standard illness management protocol. Following a preestablished emergency plan for the assessment of suicidality was successful. This serves as a model for using technology to manage comorbid depression and chronic illness.

Antiamyloid Drugs May Offer Hope for AD

Antiamyloid Drugs May Offer Hope for AD

Computer screen photo-assisted techniques for global monitoring of environmental and sanitary parameters

The computer screen photo-assisted technique (CSPT) is a measuring method that uses regular computer screens as controlled light sources and web cameras as imaging detectors for optical evaluations of sensing substances, which optical properties respond to target analytes. The fact, that CSPT uses a globally distributed and familiar infrastructure as instrumentation and that is able to serve multiple targets with the same setup, makes it an attractive candidate for home testing. This article reviews the CSPT concept and focuses in two recent studies that demonstrate thorough CSPT determinations using a handy and eventually disposable assay format, with the potential to be as ubiquitous as the CSPT platforms themselves. The implications of such combination of technologies is discussed, and its potential to support the global monitoring of environmental and sanitary parameters, using Internet geography browsers, is analyzed.

The effect of dose reduction on the detection of anatomical structures on panoramic radiographs

The aim was to evaluate the effect of dose reduction on diagnostic accuracy using different screen-film combinations and digital techniques for panoramic radiography. Five observers assessed 201 pairs of panoramic radiographs (a total of 402 panoramic radiographs) taken with the Orthophos Plus (Sirona, Bensheim, Germany), for visualization of 11 anatomical structures on each side, using a 3-point scale -1, 0 and 1. Two radiographs of each patient were taken at two different times (conventional setting and setting with decreased dose, done by increasing tube potential settings or halving tube current). To compare the dose at different tube potential settings dose-length product was measured at the secondary collimator. Films with medium and regular intensifying screens (high and low tube potential settings) and storage phosphor plates (low tube potential setting, tube current setting equivalent to regular intensifying screen and halved) were compared. The five observers made 27 610 assessments. Intrarater agreement was expressed by Cohen's kappa coefficient. The results demonstrated an equivalence of regular screens (low tube potential setting) and medium screens (high and low tube potential settings). A significant difference existed between medium screens (low tube potential setting, mean score 0.92) and the group of regular film-screen combinations at high tube potential settings (mean score 0.89) and between all film-screen combinations and the digital system irrespective of exposure (mean score below 0.82). There were no significant differences between medium and regular screens (mean score 0.88 to 0.92) for assessment of the periodontal ligament space, but there was a significant difference compared with the digital system (mean score below 0.76). The kappa coefficient for intrarater agreement was moderate (0.55). New regular intensifying screens can replace medium screens at low tube potential settings. Digital panoramic radiographs should be taken at low tube potential levels with an exposure equivalent at least to a regular intensifying screen.

Statistical characteristics of an intense wave behind a two-dimensional phase screen

An analysis of the parameters of nonlinear waves transmitted through a layer of a randomly inhomogeneous medium is carried out. The layer is modeled by a two-dimensional phase screen. Passing through the screen plane, the wave acquires a random phase shift. The wave front becomes distorted, and randomly located regions of ray convergence and divergence are formed, in which the nonlinear evolution of the wave alters profoundly. The problem is solved in the approximation of geometrical acoustics. The ray pattern of a plane wave transmitted through the regular screen is constructed. The solution that describes the spatial structure of the field and the evolution of an arbitrary temporal wave profile behind the screen is obtained. Statistical characteristics of the discontinuity amplitude are calculated for different distances from the screen. A random modulation is shown to result in a faster (in comparison with the case of a homogeneous medium) nonlinear attenuation of the wave and in the smoothing of the shock profile. The distribution function of the wave field parameters becomes broader because of random focusing effects.

A comparison of the imaging characteristics of the new Kodak Hyper Speed G film with the current T-MAT G/RA film and the CR 9000 system

Three standard radiation qualities (RQA 3, RQA 5 and RQA 9) and two screens, Kodak Lanex Regular and Insight Skeletal, were used to compare the imaging performance and dose requirements of the new Kodak Hyper Speed G and the current Kodak T-MAT G/RA medical x-ray films. The noise equivalent quanta (NEQ) and detective quantum efficiencies (DQE) of the four screen–film combinations were measured at three gross optical densities and compared with the characteristics for the Kodak CR 9000 system with GP (general purpose) and HR (high resolution) phosphor plates. The new Hyper Speed G film has double the intrinsic sensitivity of the T-MAT G/RA film and a higher contrast in the high optical density range for comparable exposure latitude. By providing both high sensitivity and high spatial resolution, the new film significantly improves the compromise between dose and image quality. As expected, the new film has a higher noise level and a lower signal-to-noise ratio than the standard film, although in the high frequency range this is compensated for by a better resolution, giving better DQE results—especially at high optical density. Both screen–film systems outperform the phosphor plates in terms of MTF and DQE for standard imaging conditions (Regular screen at RQA 5 and RQA 9 beam qualities). At low energy (RQA 3), the CR system has a comparable low-frequency DQE to screen–film systems when used with a fine screen at low and middle optical densities, and a superior low-frequency DQE at high optical density.

Performance comparison of an active matrix flat panel imager, computed radiography system, and a screen-film system at four standard radiation qualities

Four standard radiation qualities (from RQA 3 to RQA 9) were used to compare the imaging performance of a computed radiography (CR) system (general purpose and high resolution phosphor plates of a Kodak CR 9000 system), a selenium-based direct flat panel detector (Kodak Direct View DR 9000), and a conventional screen-film system (Kodak T-MAT L/RA film with a 3M Trimax Regular screen of speed 400) in conventional radiography. Reference exposure levels were chosen according to the manufacturer's recommendations to be representative of clinical practice (exposure index of 1700 for digital systems and a film optical density of 1.4). With the exception of the RQA 3 beam quality, the exposure levels needed to produce a mean digital signal of 1700 were higher than those needed to obtain a mean film optical density of 1.4. In spite of intense developments in the field of digital detectors, screen-film systems are still very efficient detectors for most of the beam qualities used in radiology. An important outcome of this study is the behavior of the detective quantum efficiency of the digital radiography (DR) system as a function of beam energy. The practice of users to increase beam energy when switching from a screen-film system to a CR system, in order to improve the compromise between patient dose and image quality, might not be appropriate when switching from screen-film to selenium-based DR systems.

The Idealization of Contingency in Traditional Japanese Aesthetics

In many popular writings that date from initial decades of twentieth century, and also in recent scholarly studies, aesthetics-insofar as we can speak sweepingly of a complicated, multidimensional, and dynamic historical phenomenon-is characterized with a set of adjectives whose present linguistic entrenchment is clearly evident. Specifically we read that traditional Japanese aesthetics is an aesthetics of imperfection, insufficiency, incompleteness, asymmetry, and irregularity, not to mention perishability, suggestiveness, and simplicity.1 Given this collection of qualities, we are presented with a matching set of paradigmatic Japanese aesthetic experiences and objects, both as illustrations and as legitimations of this close-to-standard portrait. Examples include suggestive moon covered by drifting clouds, irregularly formed ceramics of ceremonial teacups, simple and asymmetrical arrangement of unpolished rocks in dry landscape garden, bold and dashing monochromatic strokes typical of Zen calligraphy, transient cherry blossoms, serene and cloud-capped mountain summits, lonely thatched huts, sunsets in foggy twilight, call of a crane that breaks through silence, and light autumn rain that drizzles upon a secluded pond. Upon further reflection, it becomes noticeable that some familiar Japanese aesthetic objects do not easily conform to this standard picture, and this raises doubts about typical characterization of Japanese aesthetics. The quintessentially Japanese shoji screens and tatami mats, for instance, are uniformly rectangular rather than irregular in form. They are, moreover, neither asymmetrical, nor imperfect, nor incomplete, nor insufficient. How then, can these perfectly regular screens and mats-items crucial to aesthetics of Japanese domestic architecture-fit neatly into usually encountered portrait of traditional Japanese aesthetics, if it is said to be fundamentally the worship of imperfection?2 Or similarly if imperfection is

Rationale and feasibility of chemoprovention of hepatocellular carcinoma by cyclooxygenase-2 inhibitors

Hepatocellular carcinoma (HCC) is a growing health problem worldwide. The limited treatment and poor prognosis of this disease emphasizes the importance of developing effective prevention, including chemoprevention. Improvement in early diagnosis of HCC and regular screen of individuals with increased risk for HCC provide the possibility of effective chemoprevention for HCC in the future. Hepatocarcinogenesis is best described as a continuity of regeneration, proliferation, unregulated hyperplasia, dysplasia, and malignant transformation. Uncontrolled proliferation of hepatocytes clearly plays a key role in hepatocarcinogenesis. Overexpression of cyclooxygenase-2 (COX-2) has been associated with tumorigenesis of colon cancer. Selective COX-2 inhibitors possess potent suppression on the growth of colon cancer. Overexpression of COX-2 has also recently been demonstrated in patients with HCC, especially in nontumorous tissue with cirrhosis and well-differentiated tumorous tissue. In vitro studies have revealed that both NS-398, a selective COX-2 inhibitor, and sulindac, an analog of nonsteroidal anti-inflammatory drugs, effectively inhibit growth of human hepatoma cell lines, which is mediated by a decreased rate of cell proliferation. Although further in vivo studies are required in animal models to confirm these findings and define optimal doses for future clinical trials in human subjects, these findings provide a rationale for the use of COX-2 inhibitors as HCC chemoprevention. (J Lab Clin Med 2002;139:234-43)

Image-quality performance of an a-Si : H-based X-ray imaging system for digital mammography

We have been investigating the potential of large area active matrix flat-panel a-Si : H imaging arrays for full-field digital X-ray mammography. To optimise the overall performance of such an imaging system under mammographic conditions, four different Gd 2O 2S : Tb phosphor screens (i.e. Lanex Fast-Back, Regular, Fine and MinR-2000) were employed and our full-field detector was integrated with the Feinfocus DIMA (Direct Magnification) PLUS MII mammographic unit. The spatial resolution and the image noise of the digital detector were measured and the X-ray imaging performance of the whole system was also evaluated with two mammographic phantoms. It was deduced from the results of this study that Regular screen offers the best compromise between sensitivity and spatial resolution and exhibits better overall image-quality performance than that of a conventional mammography system.

Neugebauer and Demichel: Dependence and independence inn-screen superpositions for colour printing

The Neugebauer equations and the Demichel equations on which they are based are one of the basic tools for modeling colour printing systems that use the halftoning technique. However, these equations implicitly assume that the colour ink distributions in the screen superposition are statistically independent. We show that this condition is not satisfied in the conventional screen superposition used for colour printing, and we discuss the consequences of this fact. Furthermore, we give a precise criterion that determines, for any number of superposed regular screens, in which cases the Demichel (and hence the Neugebauer) equations are satisfied, and in which cases they fail: The Demichel equations fail in all cases where the screen superposition is singular, and they are satisfied in all nonsingular screen superpositions. We illustrate our results with several examples of both cases. © 2000 John Wiley & Sons, Inc. Col Res Appl, 25, 267–277, 2000

Charge-coupled device panoramic radiography: effect of beam energy on radiation exposure.

To determine the consequences for entrance exposure of varying the beam energy and operating current for panoramic radiography using a charge-coupled device receptor. Images were made of a RANDO average man phantom (Alderson Research Laboratories, Stamford, CT) at kVcp settings of 60, 66, 70 and 80 and an mA of 2.0, 3.2, 6.4 and 10.0. The exposure cycle was set as recommended by the manufacturer at 17.6 s. Diagnostic image quality was rated by a panel of two oral and maxillofacial radiologists and one oral and maxillofacial pathologist. Entrance exposures were assessed using a 3 cc ionization chamber placed at the beam entry points while imaging the molar, premolar, and anterior teeth both using the DigiPan (Trophy Radiologie, Vincennes, France) CCD receptor and conventional T-Mat G film/Lanex Regular screens (Eastman Kodak, Rochester, NY, USA). Acceptable image quality was attained with combinations of 60 kVcp and 3.2, 6.4 or 10 mA, 70 kVcp and 2.0, 3.2 or 6.4 mA; at 80 kVcp irrespective of the mA it was unacceptable. The maximum reduction in entrance dose was 77%, averaged over the three sites, at 70 kVcp and 2 mA. The DigiPan receptor produces satisfactory images with saving in entry exposure saving of approximately 70% when compared with a conventional film/rare earth screen combination.

Image layer characteristics of the PC 1000 (mark II)

The objective of this study was to investigate empirically the image layer characteristics of the PC 1000 Mark II. Radiographs were taken of a lead resolution grid positioned at 1 mm increments along angular intervals of the projected x-ray beam. The receptor was T-Mat G film combined with Lanex Regular Screens. The path of the effective rotation center was determined using a film positioned horizontally at right angles to the slit beam. The vertical magnification factor, horizontal magnification and Distortion Index, corrected for the position of the tomographic layer, were calculated using a reference object placed at various resolution limits of the image layer. The beam projection angle was compared to the average dental arch shape and proximal contact angle.

Vision screening, eye examination and risk assessment of display screen users in a large regional teaching hospital

SummaryIn January 1993 the Royal Group of Hospitals Trust, which employs approximately 5000 staff, implemented the Health and Safety (Display Screen Equipment) Northern Ireland Regulations (1992). During 1994 all regular display screen equipment users were offered a vision screening test. In total 571 employees were screened using computerized vision screening software (City Visual Systems Ltd). Risk assessments were completed for 293 display screen work‐stations. One hundred and twelve full eye examinations, carried out by optometrists, were performed on those who failed vision screening and on those who specifically requested an optometric assessment. Results indicate that whereas the proportion of users experiencing visual and general symptoms differed markedly from department to department (28–82%), the median number of individuals failing the screening test was 25% (range 9–40%), Those involved in uninterrupted display screen equipment work for prolonged periods reported visual and general work‐related symptoms twice as frequently as those who spent less time working with DSE. The outcome of full eye examinations confirmed that less than 5% of display screen users required spectacles solely for display screen use. Work‐station analysis indicated that ergonomic problems were common. The authors conclude that the successful management of health risks from display screen equipment requires simultaneous attention to work‐place design, working patterns and eye care.

Vision screening, eye examination and risk assessment of display screen users in a large regional teaching hospital

In January 1993 the Royal Group of Hospitals Trust, which employs approximately 5000 staff, implemented the Health and Safety (Display Screen Equipment) Northern Ireland Regulations (1992). During 1994 all regular display screen equipment users were offered a vision screening test. In total 571 employees were screened using computerized vision screening software (City Visual Systems Ltd). Risk assessments were completed for 293 display screen work-stations. One hundred and twelve full eye examinations, carried out by optometrists, were performed on those who failed vision screening and on those who specifically requested an optometric assessment. Results indicate that whereas the proportion of users experiencing visual and general symptoms differed markedly from department to department (28-82%), the median number of individuals failing the screening test was 25% (range 9-40%). Those involved in uninterrupted display screen equipment work for prolonged periods reported visual and general work-related symptoms twice as frequently as those who spent less time working with DSE. The outcome of full eye examinations confirmed that less than 5% of display screen users required spectacles solely for display screen use. Work-station analysis indicated that ergonomic problems were common. The authors conclude that the successful management of health risks from display screen equipment requires simultaneous attention to work-place design, working patterns and eye care.

Film-screen systems: Sensitometric comparison of Kodak Ektavision system to Kodak T-Mat/RA system

Background. In 1995, Eastman Kodak Company (Rochester, N.Y.) marketed the Ektavision Extraoral Imaging Film and Screen System. It produced high-resolution images by keeping the light emitted by intensifying screens from “punching through” one emulsion layer on the film to another. Objectives. The objectives of the experiment were (1) to compare the sensitometric properties of the Ektavision system to its predecessor, the T-Mat/RA system and (2) to determine whether films and screens of the Ektavision and the T-Mat/RA systems could be interchanged without clinically changing the sensitometric properties. Ektavision and Lanex Regular intensifying screens were used in combination with Ektavision, T-Mat G/RA, T-Mat L/RA, and T-Mat H/RA films. Results. The results showed that the Ektavision film was slightly slower than the T-Mat G/RA film no matter what type of screen was used. The type of screen used had little effect on inherent contrast or exposure latitude. The Ektavision film had approximately similar inherent contrast as the T-Mat G/RA film but less than that of the T-Mat H/RA film; its latitude was less than that of the T-Mat L/RA film. The manufacturer does not recommend combining T-Mat/RA film with Ektavision screens or Lanex Regular screens with Ektavision film because of a possible reduction in image resolution. But this mismatch did not clinically affect inherent contrast and exposure latitude; however, film speed was slightly affected. Conclusions. The Ektavision system is the result of advanced technology that produces images of high resolution. The high-resolution Ektavision film is slightly slower than the T-Mat G/RA film but is equivalent to it in its contrast and latitude. Therefore when changing from the combination of T-Mat/RA film plus Lanex Regular screens to that of Ektavision film plus Ektavision screens, a slight increase in x-radiation exposure should be made.