WorldWideScience

Sample records for digital radiography detectors

  1. Digital radiography: Present detectors and future developments

    International Nuclear Information System (INIS)

    Perez-Mendez, V.

    1990-08-01

    Present detectors for digital radiography are of two classes: real time detectors and storage (non real time) types. Present real time detectors consist of image intensifier tubes with an internal cesium iodide layer x-ray converter. Non real time detectors involve linear sweep arrays or storage detectors such as film. Future detectors discussed here can be of both types utilizing new technologies such as hydrogenated amorphous silicon photodiode arrays coupled to thin film transistor arrays. 17 refs., 10 figs

  2. Digital radiography detectors - A technical overview: Part 1

    International Nuclear Information System (INIS)

    Lanca, Luis; Silva, Augusto

    2009-01-01

    During the last two decades screen-film (SF) systems have been replaced by digital X-ray systems. The advent of digital technologies brought a number of digital solutions based on different detector and readout technologies. Improvements in technology allowed the development of new digital technologies for projection radiography such as computed radiography (CR) and digital radiography (DR). The large number of scientific papers concerning digital X-ray systems that have been published over the last 25 years indicates the relevance of these technologies in healthcare. There are important differences among different detector technologies that may affect system performance and image quality for diagnostic purposes. Radiographers are expected to have an effective understanding of digital X-ray technologies and a high level of knowledge and awareness concerning the capabilities of these systems. Patient safety and reliable diagnostic information are intrinsically linked to these factors. In this review article - which is the first of two parts - a global overview of the digital radiography systems (both CR and DR) currently available for clinical practice is provided

  3. Digital radiography

    International Nuclear Information System (INIS)

    Brody, W.R.

    1984-01-01

    Digital Radiography begins with an orderly introduction to the fundamental concepts of digital imaging. The entire X-ray digital imagining system is described, from an overall characterization of image quality to specific components required for a digital radiographic system. Because subtraction is central to digital radiographic systems, the author details the use of various subtraction methods for image enhancement. Complex concepts are illustrated with numerous examples and presented in terms that can readily be understood by physicians without an advanced mathematics background. The second part of the book discusses implementations and applications of digital imagining systems based on area and scanned detector technologies. This section includes thorough coverage of digital fluoroscopy, scanned projection radiography, and film-based digital imaging systems, and features a state-of-the-art synopsis of the applications of digital subtraction angiography. The book concludes with a timely assessment of anticipated technological advances

  4. Integrated digital radiography with electronic flat detectors

    International Nuclear Information System (INIS)

    Neitzel, U.

    1997-01-01

    If some years ago 'better' pictures was the motive to opt for the novel digital technology in radiographic systems, the goals today are rationalisation of the workflow and reduction of costs, with equal diagnostic image quality and - if possible - reduction of patient doses being taken for granted. Cost reductions, however, can be achieved only in terms of current costs, as the new digital equipment requires high investment. Possibilities of reducing current costs are opened up through higher patient throughput due to faster, better and less complicated examination technique, optimisation of communication systems for data and image transmission within the radiology department and to the clinical departments, and through reducing or avoiding materials costs, such as for radiographic films and film development. (orig./CB) [de

  5. Digital radiography

    International Nuclear Information System (INIS)

    Coulomb, M.; Dal Soglio, S.; Pittet-Barbier, L.; Ranchoup, Y.; Thony, F.; Ferretti, G.; Robert, F.

    1992-01-01

    Digital projection radiography may replace conventional radiography some day, provided it can meet several requirements: equal or better diagnostic effectiveness of the screen-film systems; reasonable image cost; real improvement in the productivity of the Departments of Imaging. All digital radiographic systems include an X-ray source, an image acquisition and formatting sub-system, a display and manipulation sub-system, and archiving subsystem and a laser editing system, preferably shared by other sources of digital images. Three digitization processes are available: digitization of the radiographic film, digital fluorography and phospholuminescent detectors with memory. The advantages of digital fluoroscopy are appealing: real-time image acquisition, suppression of cassettes; but its disadvantages are far from negligible: it cannot be applied to bedside radiography, the field of examination is limited, and the wide-field spatial resolution is poor. Phospholuminescent detectors with memory have great advantages: they can be used for bedside radiographs and on all the common radiographic systems; spatial resolution is satisfactory; its current disadvantages are considerable. These two systems, have common properties making up the entire philosophy of digital radiology and specific features that must guide our choice according to the application. Digital fluorography is best applied in pediatric radiology. However, evaluation works have showed that it was applicable with sufficient quality to many indications of general radiology in which a fluoroscopic control and fast acquisition of the images are essential; the time gained on the examination may be considerable, as well as the savings on film. Detectors with memory are required for bedside radiographs, in osteoarticular and thoracic radiology, in all cases of traumatic emergency and in the resuscitation and intensive care departments

  6. Defective pixel map creation based on wavelet analysis in digital radiography detectors

    International Nuclear Information System (INIS)

    Park, Chun Joo; Lee, Hyoung Koo; Song, William Y.; Achterkirchen, Thorsten Graeve; Kim, Ho Kyung

    2011-01-01

    The application of digital radiography detectors has attracted increasing attention in both medicine and industry. Since the imaging detectors are fabricated by semiconductor manufacturing process over large areas, defective pixels in the detectors are unavoidable. Moreover, the radiation damage due to the routine use of the detectors progressively increases the density of defective pixels. In this study, we present a method of identifying defective pixels in digital radiography detectors based on wavelet analysis. Artifacts generated due to wavelet transformations have been prevented by an additional local threshold method. The proposed method was applied to a sample digital radiography and the result was promising. The proposed method uses a single pair of dark and white images and does not require them to be corrected in gain-and-offset properties. This method will be helpful for the reliable use of digital radiography detectors through the working lifetime.

  7. Digital radiography

    International Nuclear Information System (INIS)

    Zani, M.L.

    2002-01-01

    X-ray radiography is a very common technique used to check the homogeneity of a material or the inside of a mechanical part. Generally the radiation that goes through the material to check, produced an image on a sensitized film. This method requires time because the film needs to be developed, digital radiography has no longer this inconvenient. In digital radiography the film is replaced by digital data and can be processed as any computer file. This new technique is promising but its main inconvenient is that today its resolution is not so good as that of film radiography. (A.C.)

  8. Evaluation of digital detector arrays systems for industrial radiography

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Aline S.S.; Oliveira, Davi F.; Gomes, Célio S.; Azeredo, Soraia R.; Lopes, Ricardo T., E-mail: aline@lin.ufrj.br, E-mail: davi@lin.ufrj.br.br, E-mail: celio@lin.ufrj.br, E-mail: soraia@lin.ufrj.br, E-mail: ricardo@lin.ufrj.br, E-mail: davi.oliveira@uerj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Instrumentação Nuclear

    2017-07-01

    Digital Detector Arrays (DDA) or Flat Panel Detector (FPD) is a highly efficient technique that is used in nondestructive testing of internal features of an object. The evaluation of DDA systems for industrial radiography is important to ensure the image quality and to enables long-term stability of this system. This evaluation is specified by ASTM E2737 - 10, which describes the fundamental parameters of DDA systems to be measured. The tests require the usage of either the five-groove wedge or the duplex plate phantom with separate Image Quality Indicators (IQIs). The purpose of this work was evaluate the radiographic performance achieved using both techniques in two DDA systems manufactured by GEIT: DXR250P and DXR250V, which have thallium-doped cesium iodide (CsI:Tl) and terbium-doped gadolinium oxysulfide (Gd{sub 2}O{sub 2}S:Tb - GOS) scintillators, respectively. For this purpose, it was used an X-ray equipment as radiation source. The image quality parameters analyzed were Image Lag (IL), Offset Level (OL), Bad Pixel distribution, Burn In (BI), Spatial Resolution (SR), Material Thickness Range (MTR), Contrast Sensitivity (CS), Signal Level (SL) and Signal-to-Noise Ratio (SNR). As result of this study, has been observed that the use of the five-groove wedge phantom made the measurements to become easier to execute. Regarding the DDA system, the DXR250P presented more IL and BI, but produced images with better CS and SNR and needed a dose almost twice smaller than the DXR250V to achieve a similar SL. (author)

  9. Evaluation of digital detector arrays systems for industrial radiography

    International Nuclear Information System (INIS)

    Silva, Aline S.S.; Oliveira, Davi F.; Gomes, Célio S.; Azeredo, Soraia R.; Lopes, Ricardo T.

    2017-01-01

    Digital Detector Arrays (DDA) or Flat Panel Detector (FPD) is a highly efficient technique that is used in nondestructive testing of internal features of an object. The evaluation of DDA systems for industrial radiography is important to ensure the image quality and to enables long-term stability of this system. This evaluation is specified by ASTM E2737 - 10, which describes the fundamental parameters of DDA systems to be measured. The tests require the usage of either the five-groove wedge or the duplex plate phantom with separate Image Quality Indicators (IQIs). The purpose of this work was evaluate the radiographic performance achieved using both techniques in two DDA systems manufactured by GEIT: DXR250P and DXR250V, which have thallium-doped cesium iodide (CsI:Tl) and terbium-doped gadolinium oxysulfide (Gd 2 O 2 S:Tb - GOS) scintillators, respectively. For this purpose, it was used an X-ray equipment as radiation source. The image quality parameters analyzed were Image Lag (IL), Offset Level (OL), Bad Pixel distribution, Burn In (BI), Spatial Resolution (SR), Material Thickness Range (MTR), Contrast Sensitivity (CS), Signal Level (SL) and Signal-to-Noise Ratio (SNR). As result of this study, has been observed that the use of the five-groove wedge phantom made the measurements to become easier to execute. Regarding the DDA system, the DXR250P presented more IL and BI, but produced images with better CS and SNR and needed a dose almost twice smaller than the DXR250V to achieve a similar SL. (author)

  10. Digital radiography

    International Nuclear Information System (INIS)

    Kusano, Shoichi

    1993-01-01

    Firstly, from an historic point of view, fundamental concepts on digital imaging were reviewed to provide a foundation for discussion of digital radiography. Secondly, this review summarized the results of ongoing research in computed radiography that replaces the conventional film-screen system with a photo-stimulable phosphor plate; and thirdly, image quality, radiation protection, and image processing techniques were discussed with emphasis on picture archiving and communication system environment as our final goal. Finally, future expansion of digital radiography was described based on the present utilization of computed tomography at the National Defense Medical College Hospital. (author) 60 refs

  11. Digital chest radiography: flat-panel detectors or conventional radiographs

    International Nuclear Information System (INIS)

    Schaefer-Prokop, C.; Uffmann, M.; Sailer, J.; Kabalan, N.; Herold, C.; Prokop, M.

    2003-01-01

    Flat panel detectors are characterized by improved handling and increased dose efficiency. This allows for increasing of work flow efficiency and for reducing the exposure dose by about 50% compared to current systems with a sensitivity of 400. Whether the increased dose efficiency should be used to reduce acquisition dose or to increase image quality in the chest, will be shown by further clinical experience and will be also determined by the subjective preference of the radiologists. The decreased level of image noise opens new perspectives for image processing that way that elaborated multifrequency processing allows for optimizing the display of very small and low contrast structures that was so far limited by overlying image noise. Specialized applications of dual energy subtraction and temporal subtraction will also profit by the new detector technology and will be further driven forward in context with applications such as computed assisted diagnosis even though this is currently not yet broadly applied. Storage phosphor radiography still represents an important alternative technique based on its larger flexibility with respect to equipment configuration, its broader application options in intensive care and emergency radiology and due to economic reasons. These facts are further underlined by the fact that image quality also in storage phosphor radiography could be constantly increased by improving detector technology and image processing and consequently has a high standard. (orig.) [de

  12. Solid-state, flat-panel, digital radiography detectors and their physical imaging characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Cowen, A.R. [LXi Research, Academic Unit of Medical Physics, University of Leeds, West Yorkshire (United Kingdom)], E-mail: a.r.cowen@leeds.ac.uk; Kengyelics, S.M.; Davies, A.G. [LXi Research, Academic Unit of Medical Physics, University of Leeds, West Yorkshire (United Kingdom)

    2008-05-15

    Solid-state, digital radiography (DR) detectors, designed specifically for standard projection radiography, emerged just before the turn of the millennium. This new generation of digital image detector comprises a thin layer of x-ray absorptive material combined with an electronic active matrix array fabricated in a thin film of hydrogenated amorphous silicon (a-Si:H). DR detectors can offer both efficient (low-dose) x-ray image acquisition plus on-line readout of the latent image as electronic data. To date, solid-state, flat-panel, DR detectors have come in two principal designs, the indirect-conversion (x-ray scintillator-based) and the direct-conversion (x-ray photoconductor-based) types. This review describes the underlying principles and enabling technologies exploited by these designs of detector, and evaluates their physical imaging characteristics, comparing performance both against each other and computed radiography (CR). In standard projection radiography indirect conversion DR detectors currently offer superior physical image quality and dose efficiency compared with direct conversion DR and modern point-scan CR. These conclusions have been confirmed in the findings of clinical evaluations of DR detectors. Future trends in solid-state DR detector technologies are also briefly considered. Salient innovations include WiFi-enabled, portable DR detectors, improvements in x-ray absorber layers and developments in alternative electronic media to a-Si:H.

  13. Digital radiography in NDT applications

    International Nuclear Information System (INIS)

    Deprins, E.

    2004-01-01

    A lot of film radiography could be replaced by today's technologies in the field of digital radiography. Only few of these applications have indeed replaced film. The choice to go digital depends on cost, quality requirement, workflow and throughput. Digital images offer a lot of advantages in terms of image manipulation and workflow. But despite the many advantages, a lot of considerations are needed before someone can decide to convert his organization from conventional to digital radiography. This paper gives an overview of all different modalities that can be used in digital radiography with today's technologies, together with the experiences of the pioneers of digital radiography. Film Scanning, Computed Radiography and Digital Radiography by using of different kinds of flat panel detectors all have their specific application fields and customers. What is the status of the technology today, which advantages brings digital radiography, and which are the limitations radiographers have to consider when replacing film by digital systems. (author)

  14. Digital Radiography

    Science.gov (United States)

    1986-01-01

    System One, a digital radiography system, incorporates a reusable image medium (RIM) which retains an image. No film is needed; the RIM is read with a laser scanner, and the information is used to produce a digital image on an image processor. The image is stored on an optical disc. System allows the radiologist to "dial away" unwanted images to compare views on three screens. It is compatible with existing equipment and cost efficient. It was commercialized by a Stanford researcher from energy selective technology developed under a NASA grant.

  15. Photon-counting digital radiography using high-pressure xenon filled detectors

    CERN Document Server

    Li, Maozhen; Johns, P C

    2001-01-01

    Digital radiography overcomes many of the limitations of the traditional screen/film system. Further enhancements in the digital radiography image are possible if the X-ray image receptor could measure the energy of individual photons instead of simply integrating their energy, as is the case at present. A prototype photon counting scanned projection radiography system has been constructed, which combines a Gas Electron Multiplier (GEM) and a Gas Microstrip Detector (GMD) using Xe : CH sub 4 (90 : 10) at high pressure. With the gain contribution from the GEM, the GMD can be operated at lower and safer voltages making the imaging system more reliable. Good energy resolution, and spatial resolution comparable to that of screen/film, have been demonstrated for the GEM/GMD hybrid imaging system in photon counting mode for X-ray spectra up to 50 kV.

  16. Progress in digital radiography

    International Nuclear Information System (INIS)

    Cappelle, A.

    2016-01-01

    Because of its practical aspect digital radiography is more and more used in the industrial sector. There are 2 kinds of digital radiography. First, the 'computed radiography' that uses a photon-stimulated screen, and after radiation exposure this screen must be read by an analyser to get a digit image. The second type is the 'direct radiography' that allows one to get a digit radiograph of the object directly. Digital radiography uses the same radioactive nuclides as radiography with silver films: cobalt, iridium or selenium. The spatial resolution of digital radiography is less good than with classical silver film radiography but digital radiography offers a better visual contrast. (A.C.)

  17. Digital radiography with large-area flat-panel detectors

    International Nuclear Information System (INIS)

    Kotter, E.; Langer, M.

    2002-01-01

    Large-area flat-panel detectors with active readout mechanisms have been on the market for the past 2 years. This article describes different detector technologies. An important distinction is made between detectors with direct and those with indirect conversion of X-rays into electrical charges. Detectors with indirect conversion are built with unstructured or structured scintillators, the latter resulting in less lateral diffusion of emitted light. Some important qualities of flat-panel detectors are discussed. The first phantom and clinical studies published report an image quality at least comparable to that of screen-film systems and a potential for dose reduction. The available studies are summarised in this article. (orig.)

  18. Digital radiography

    DEFF Research Database (Denmark)

    Precht, H; Gerke, O; Rosendahl, K

    2012-01-01

    BACKGROUND: New developments in processing of digital radiographs (DR), including multi-frequency processing (MFP), allow optimization of image quality and radiation dose. This is particularly promising in children as they are believed to be more sensitive to ionizing radiation than adults....... OBJECTIVE: To examine whether the use of MFP software reduces the radiation dose without compromising quality at DR of the femur in 5-year-old-equivalent anthropomorphic and technical phantoms. MATERIALS AND METHODS: A total of 110 images of an anthropomorphic phantom were imaged on a DR system (Canon DR...... with CXDI-50 C detector and MLT[S] software) and analyzed by three pediatric radiologists using Visual Grading Analysis. In addition, 3,500 images taken of a technical contrast-detail phantom (CDRAD 2.0) provide an objective image-quality assessment. RESULTS: Optimal image-quality was maintained at a dose...

  19. Pediatric radiation dose management in digital radiography

    International Nuclear Information System (INIS)

    Neitzel, U.

    2004-01-01

    Direct digital radiography (DR) systems based on flat-panel detectors offer improved dose management in pediatric radiography. Integration of X-ray generation and detection in one computer-controlled system provides better control and monitoring

  20. Digital radiography

    International Nuclear Information System (INIS)

    Elander, S.; Hellesnes, J.; Reitan, J.B.

    1992-01-01

    The technology of radiography is developing rapidly, both regarding imaging technology and data hardware, and software technology. More and more advanced systems are marketed by the radiological companies. The wide product range makes it difficult to get an overview over principles and components. By closer inspection, however, the number of basic components and technologies is limited. Moreover, the components seem rather well known from other technologies, due to the long times of development in radiology. This report gives a survey of some new principles and components in the video chain. As components may deteriorate or age fast by irradiation, the radiation levels in the chain are evaluated. 13 refs

  1. Digital radiography

    International Nuclear Information System (INIS)

    Rath, M.; Lissner, J.; Rienmueller, R.; Haendle, J.; Siemens A.G., Erlangen

    1984-01-01

    Using a prototype of an electronic, universal examination unit equipped with a special X-ray TV installation, spotfilm exposures and digital angiographies with high spatial resolution and wide-range contrast could be made in the clinic for the first time. With transvenous contrast medium injection, the clinical results of digital angiography show excellent image quality in the region of the carotids and renal arteries as well as the arteries of the extremities. The electronic series exposures have an image quality almost comparable to the quality obtained with cutfilm changers in conventional angiography. There are certain limitations due to the input field of 25 cm X-ray image intensified used. In respect of the digital angiography imaging technique, the electronic universal unit is fully suitable for clinical application. (orig.) [de

  2. Feasibility study of flexible flat-panel X-ray detectors for digital radiography

    International Nuclear Information System (INIS)

    Joe, Ok La; Yun, Seung Man; Kim, Ho Kyung

    2010-01-01

    Flexible flat-panel detectors (FPDs), which utilize both organic photodiode (OPD) and organic thin-film transistor (OTFT) technologies, are recently concerned in digital radiography. The flexible FPD has several potential advantages, such as high accessibility to patient, avoidance of geometrical burr due to the oblique angle incidence of X-ray, great reduction in manufacturing cost due to jet-printing. At once, The OPD/OTFT arrays were fabricated by jet-printing techniques, mechanical robustness due to plastic substrates, and so on. In this study, we have investigated the feasibility of flexible FPD by comparing theoretical detective quantum efficiency (DQE) with that of the conventional amorphous silicon-based FPD. We chose copper phthalocyanine-fullerene (CuPc-C60) organic materials for the construction of the flexible FPD. DQE was calculated by the linear-systems transfer theory

  3. Scan equalization digital radiography (SEDR) implemented with an amorphous selenium flat-panel detector: initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xinming; Lai Chaojen; Chen Lingyun; Han Tao; Zhong Yuncheng; Shen Youtao; Wang Tianpeng; Shaw, Chris C [Department of Imaging Physics, Digital Imaging Research Laboratory, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030-4009 (United States)], E-mail: xliu@di.mdacc.tmc.edu

    2009-11-21

    It is well recognized in projection radiography that low-contrast detectability suffers in heavily attenuating regions due to excessively low x-ray fluence to the image receptor and higher noise levels. Exposure equalization can improve image quality by increasing the x-ray exposure to heavily attenuating regions, resulting in a more uniform distribution of exposure to the detector. Image quality is also expected to be improved by using the slot-scan geometry to reject scattered radiation effectively without degrading primary x-rays. This paper describes the design of a prototype scan equalization digital radiography (SEDR) system implemented with an amorphous silicon (a-Si) thin-film transistor (TFT) array-based flat-panel detector. With this system, slot-scan geometry with alternate line erasure and readout (ALER) technique was used to achieve scatter rejection. A seven-segment beam height modulator assembly was mounted onto the fore collimator to regulate exposure regionally for chest radiography. The beam modulator assembly, consisting of micro linear motors, lead screw cartridge with lead (Pb) beam blockers attached, position feedback sensors and motor driver circuitry, has been tested and found to have an acceptable response for exposure equalization in chest radiography. An anthropomorphic chest phantom was imaged in the posterior-anterior (PA) view under clinical conditions. Scatter component, primary x-rays, scatter-to-primary ratios (SPRs) and primary signal-to-noise ratios (PSNRs) were measured in the SEDR images to evaluate the rejection and redistribution of scattered radiation, and compared with those for conventional full-field imaging with and without anti-scatter grid methods. SPR reduction ratios (SPRRRs, defined as the differences between the non-grid full-field SPRs and the reduced SPRs divided by the former) yielded approximately 59% for the full-field imaging with grid and 82% for the SEDR technique in the lungs, and 77% for the full

  4. Figures of merit for detectors in digital radiography. II. Finite number of secondaries and structured backgrounds

    International Nuclear Information System (INIS)

    Pineda, Angel R.; Barrett, Harrison H.

    2004-01-01

    The current paradigm for evaluating detectors in digital radiography relies on Fourier methods. Fourier methods rely on a shift-invariant and statistically stationary description of the imaging system. The theoretical justification for the use of Fourier methods is based on a uniform background fluence and an infinite detector. In practice, the background fluence is not uniform and detector size is finite. We study the effect of stochastic blurring and structured backgrounds on the correlation between Fourier-based figures of merit and Hotelling detectability. A stochastic model of the blurring leads to behavior similar to what is observed by adding electronic noise to the deterministic blurring model. Background structure does away with the shift invariance. Anatomical variation makes the covariance matrix of the data less amenable to Fourier methods by introducing long-range correlations. It is desirable to have figures of merit that can account for all the sources of variation, some of which are not stationary. For such cases, we show that the commonly used figures of merit based on the discrete Fourier transform can provide an inaccurate estimate of Hotelling detectability

  5. Digital radiography in space.

    Science.gov (United States)

    Hart, Rob; Campbell, Mark R

    2002-06-01

    With the permanent habitation of the International Space Station, the planning of longer duration exploration missions, and the possibility of space tourism, it is likely that digital radiography will be needed in the future to support medical care in space. Ultrasound is currently the medical imaging modality of choice for spaceflight. Digital radiography in space is limited because of prohibitive launch costs (in the region of $20,000/kg) that severely restrict the volume, weight, and power requirements of medical care hardware. Technological increases in radiography, a predicted ten-fold decrease in future launch costs, and an increasing clinical need for definitive medical care in space will drive efforts to expand the ability to provide medical care in space including diagnostic imaging. Normal physiological responses to microgravity, in conjunction with the high-risk environment of spaceflight, increase the risk of injury and could imply an extended recovery period for common injuries. The advantages of gravity on Earth, such as the stabilization of patients undergoing radiography and the drainage of fluids, which provide radiographic contrast, are unavailable in space. This creates significant difficulties in patient immobilization and radiographic positioning. Gravity-dependent radiological signs, such as lipohemarthrosis in knee and shoulder trauma, air or fluid levels in pneumoperitoneum, pleural effusion, or bowel obstruction, and the apical pleural edge in pneumothorax become unavailable. Impaired healing processes such as delayed callus formation following fracture will have implications on imaging, and recovery time lines are unknown. The confined nature of spacecraft and the economic impossibility of launching lead-based personal protective equipment present significant challenges to crew radiation safety. A modified, free-floating radiographic C-arm device equipped with a digital detector and utilizing teleradiology support is proposed as a

  6. Digital chest radiography

    DEFF Research Database (Denmark)

    Debess, Jeanne Elisabeth; Johnsen, Karen Kirstine; Thomsen, Henrik

    on collimation and dose reduction in digital chest radiography Methods and Materials A retrospective study of digital chest radiography is performed to evaluate the primary x-ray tube collimation of the PA and lateral radiographs. Data from one hundred fifty self-reliant female patients between 15 and 55 years...

  7. Transitioning to digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, F., E-mail: Francisco.Miranda@pwc.ca [Pratt & Whitney Canada, Longueuil, Quebec (Canada)

    2015-09-15

    This article provides insight on the technical and business considerations necessary to implement or to transition to digital radiography Continued refinements in digital radiography technology have resulted in significant improvements in image quality and detectability of indications. These improvements have resulted in the acceptance of the technology by users and aerospace primes for final product inspection and disposition. Digital radiography has also been identified as an interesting cost reduction initiative with the potential of providing gains in productivity through increased throughput and decreased inspection lead-times and resulting costs. (author)

  8. Digital radiography using scintillating screens

    International Nuclear Information System (INIS)

    Salvini, E.

    1988-01-01

    This paper briefly describes the technical features of a digital radiographic system based on the principle of scanning laser stimulated luminescence. Such aspects as the physics of the stimulable phosphor detector are dealt with, and image acquisition, processing, and hard-copy output. Automatic analysis of pixel histograms is described, in a qualitative way, together with contrast modifications and spatial filtering. Physical image characteristics are reported. The overall performance of digital radiography is examined, together with the current requirements and its eventual developments

  9. Computer radiography - indirect digital radiography

    International Nuclear Information System (INIS)

    Jezierski, G.

    2008-01-01

    Implementation of the new European standards for industrial radiography with the use of storage phosphor imaging plates will result in the arousing of interest among numerous laboratories in non-destructive testing with application of the new method of testing to replace conventional radiography used so far, i.e. film radiography. Computer radiography is quite commonly used for medical radiography, where the fundamental problem consists in reduction of the radiation dose during the examination of a patient. However, it must be kept in mind that industrial applications have a little bit different requirements when compared with medical radiography. The article describes only new method for radiographic testing. (author)

  10. Noise power spectrum of the fixed pattern noise in digital radiography detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Sik, E-mail: dskim@hufs.ac.kr [Department of Electronics Engineering, Hankuk University of Foreign Studies, Gyeonggi-do 449-791 (Korea, Republic of); Kim, Eun [R& D Center, DRTECH Co., Gyeonggi-do 13558 (Korea, Republic of)

    2016-06-15

    Purpose: The fixed pattern noise in radiography image detectors is caused by various sources. Multiple readout circuits with gate drivers and charge amplifiers are used to efficiently acquire the pixel voltage signals. However, the multiple circuits are not identical and thus yield nonuniform system gains. Nonuniform sensitivities are also produced from local variations in the charge collection elements. Furthermore, in phosphor-based detectors, the optical scattering at the top surface of the columnar CsI growth, the grain boundaries, and the disorder structure causes spatial sensitivity variations. These nonuniform gains or sensitivities cause fixed pattern noise and degrade the detector performance, even though the noise problem can be partially alleviated by using gain correction techniques. Hence, in order to develop good detectors, comparative analysis of the energy spectrum of the fixed pattern noise is important. Methods: In order to observe the energy spectrum of the fixed pattern noise, a normalized noise power spectrum (NNPS) of the fixed pattern noise is considered in this paper. Since the fixed pattern noise is mainly caused by the nonuniform gains, we call the spectrum the gain NNPS. We first asymptotically observe the gain NNPS and then formulate two relationships to calculate the gain NNPS based on a nonuniform-gain model. Since the gain NNPS values are quite low compared to the usual NNPS, measuring such a low NNPS value is difficult. By using the average of the uniform exposure images, a robust measuring method for the gain NNPS is proposed in this paper. Results: By using the proposed measuring method, the gain NNPS curves of several prototypes of general radiography and mammography detectors were measured to analyze their fixed pattern noise properties. We notice that a direct detector, which is based on the a-Se photoconductor, showed lower gain NNPS than the indirect-detector case, which is based on the CsI scintillator. By comparing the gain

  11. X-ray radiation detectors of 'scintillator-photoreceiving device type' for industrial digital radiography with improved spatial resolution

    International Nuclear Information System (INIS)

    Ryzhykov, V.D.; Lysetska, O.K.; Opolonin, O.D.; Kozin, D.N.

    2003-01-01

    Main types of photo receivers used in X-ray digital radiography systems are luminescent screens that transfer the optical image onto charge collection instruments, which require cooling, and semiconductor silicon detectors, which limit the contrast sensitivity. We have developed and produced X-ray radiation detectors of 'scintillator-photoreceiving device' (S-PRD) type, which are integrally located on the inverse side of the photodiode (PD). The receiving-converting circuit (RCC) is designed for data conversion into digital form and their input into PC. Software is provided for RCC control and image visualization. Main advantages of these detectors are high industrial resolution (3-5 line pairs per mm), detecting activity up to 20 μm, controlled sensitivity, low weight and small size, imaging low (0.1-0.3 mrad) object dose in real time. In this work, main characteristics of 32-, 64- and 1024-channel detectors of S-PRD type were studied and compared for X-ray sensitivity with S-PD detectors. Images of the tested objects have been obtained. Recommendations are given on the use of different scintillation materials, depending upon the purpose of a digital radiographic system. The detectors operate in a broad energy range of ionizing radiation, hence the size of the controlled object is not limited. The system is sufficiently powerful to ensure frontal (through two walls) observation of pipelines with wall thickness up to 10 cm

  12. Artifacts in digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Min, Jung Whan [Dept. of Radiological Technology, Shin Gu University, Sungnam (Korea, Republic of); Kim, Jung Min [Dept. of Radiological Technology, Korea University, Seoul (Korea, Republic of); Jeong, Hoi Woun [Dept. of Radiological Technology, Beakseok Culture University, Cheonan (Korea, Republic of)

    2015-12-15

    Digital Radiography is a big part of diagnostic radiology. Because uncorrected digital radiography image supported false effect of Patient’s health care. We must be manage the correct digital radiography image. Thus, the artifact images can have effect to make a wrong diagnosis. We report types of occurrence by analyzing the artifacts that occurs in digital radiography system. We had collected the artifacts occurred in digital radiography system of general hospital from 2007 to 2014. The collected data had analyzed and then had categorize as the occurred causes. The artifacts could be categorized by hardware artifacts, software artifacts, operating errors, system artifacts, and others. Hardware artifact from a Ghost artifact that is caused by lag effect occurred most frequently. The others cases are the artifacts caused by RF noise and foreign body in equipments. Software artifacts are many different types of reasons. The uncorrected processing artifacts and the image processing error artifacts occurred most frequently. Exposure data recognize (EDR) error artifacts, the processing error of commissural line, and etc., the software artifacts were caused by various reasons. Operating artifacts were caused when the user did not have the full understanding of the digital medical image system. System artifacts had appeared the error due to DICOM header information and the compression algorithm. The obvious artifacts should be re-examined, and it could result in increasing the exposure dose of the patient. The unclear artifact leads to a wrong diagnosis and added examination. The ability to correctly determine artifact are required. We have to reduce the artifact occurrences by understanding its characteristic and providing sustainable education as well as the maintenance of the equipments.

  13. Artifacts in digital radiography

    International Nuclear Information System (INIS)

    Min, Jung Whan; Kim, Jung Min; Jeong, Hoi Woun

    2015-01-01

    Digital Radiography is a big part of diagnostic radiology. Because uncorrected digital radiography image supported false effect of Patient’s health care. We must be manage the correct digital radiography image. Thus, the artifact images can have effect to make a wrong diagnosis. We report types of occurrence by analyzing the artifacts that occurs in digital radiography system. We had collected the artifacts occurred in digital radiography system of general hospital from 2007 to 2014. The collected data had analyzed and then had categorize as the occurred causes. The artifacts could be categorized by hardware artifacts, software artifacts, operating errors, system artifacts, and others. Hardware artifact from a Ghost artifact that is caused by lag effect occurred most frequently. The others cases are the artifacts caused by RF noise and foreign body in equipments. Software artifacts are many different types of reasons. The uncorrected processing artifacts and the image processing error artifacts occurred most frequently. Exposure data recognize (EDR) error artifacts, the processing error of commissural line, and etc., the software artifacts were caused by various reasons. Operating artifacts were caused when the user did not have the full understanding of the digital medical image system. System artifacts had appeared the error due to DICOM header information and the compression algorithm. The obvious artifacts should be re-examined, and it could result in increasing the exposure dose of the patient. The unclear artifact leads to a wrong diagnosis and added examination. The ability to correctly determine artifact are required. We have to reduce the artifact occurrences by understanding its characteristic and providing sustainable education as well as the maintenance of the equipments

  14. Portable digital electronic radiography system

    International Nuclear Information System (INIS)

    Sawicka, B.D.

    1995-01-01

    Radiography is a standard nondestructive technique in the industrial testing of materials and components. It is routinely used during the construction, maintenance and repair of nuclear plants. Traditionally, radiography is performed using photographic film (film radiography, FR). Recent developments in solid-state area imaging radiation detectors, miniature electronics and computer software/hardware techniques have brought electronic alternatives to FR. In recent years various electronic radiography (ER) techniques have served as alternatives to FR, these proved beneficial in some applications. While originally developed to provide real time imaging, ER may offer other advantages over FR, depending on the application. Work was undertaken at CRL to review progress in ER techniques and evaluate the possibility of constructing a portable DER (digital electronic radiography) system, for the inspection of power plant components. A suitable DER technique has been developed and a proof of principle portable system constructed. As this paper demonstrates, a properly designed ER system can be small and compact, while providing radiographic examination with acceptable image quality and the benefits of ER imaging. The CRL DER system can operate with radioactive sources typical of FR. While it does not replace FR, our DER system is expected to be beneficial in specific applications for Candu maintenance, reducing cost, labour and time. Practical, cost saving applications of this system are expected to include valve monitoring and foreign object location during maintenance at Candu reactors

  15. First experience with digital radiography

    International Nuclear Information System (INIS)

    Buchmann, F.

    1987-01-01

    The digital radiogram is explained, its advantages being the various possibilities of image processing, loss-free transmission, recording and storage capabilities, and in special cases, prompt availability of processed images. Digital subtraction angiography (DSA) and the high-resolution method of digital, luminescent radiography, which replaced the conventional film-foil radiography, are explained as the first developments for the introduction of digital radiography, which today already is an applicable technique. (orig./MG) [de

  16. Portable low-cost flat panel detectors for real-time digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Iovea, Mihai; Neagu, Marian; Stefanescu, Bogdan; Mateiasi, Gabriela; Porosnicu, Ioana; Angheluta, Elena [Accent Pro 2000 S.R.L., Bucharest (Romania)

    2015-07-01

    The X-ray inspection is one of the most common used non-destructive testing methods in industry applications, but for the portable X-ray digital solution are not so many accessible, low-cost and versatile detection devices. The efficiency of a non-destructive X-ray portable device is represented by the quality of digital images, by its low acquisition time combined with a high resolution, in condition of low noise and at an affordable cost. The paper presents two X-ray portable imaging systems developed by us, suitable also for aerospace NDT applications, which are also very versatile for being easily adapted for other fields that requires mobile solutions. The first device described in the paper represent a portable large-size (210 mm X 550 mm) and high-resolution (27/54 microns) flat panel detector based on linear translation of a X-Ray TDI detector, destined for various components/parts real-time transmission measurements. The second system it is also a flat panel detectors, with a size of 510 mm X 610 mm, with the detector size from 0.2 mm until 1.5 mm, which can operate by applying the dual-energy method, very useful for discriminating materials by evaluating their Atomic effective number. The high resolution and low-cost of this flat-panels widens their applicability by covering large requirements, from identifying unwanted materials within a structure until detection of very thin cracks in complex components.

  17. Portable low-cost flat panel detectors for real-time digital radiography

    International Nuclear Information System (INIS)

    Iovea, Mihai; Neagu, Marian; Stefanescu, Bogdan; Mateiasi, Gabriela; Porosnicu, Ioana; Angheluta, Elena

    2015-01-01

    The X-ray inspection is one of the most common used non-destructive testing methods in industry applications, but for the portable X-ray digital solution are not so many accessible, low-cost and versatile detection devices. The efficiency of a non-destructive X-ray portable device is represented by the quality of digital images, by its low acquisition time combined with a high resolution, in condition of low noise and at an affordable cost. The paper presents two X-ray portable imaging systems developed by us, suitable also for aerospace NDT applications, which are also very versatile for being easily adapted for other fields that requires mobile solutions. The first device described in the paper represent a portable large-size (210 mm X 550 mm) and high-resolution (27/54 microns) flat panel detector based on linear translation of a X-Ray TDI detector, destined for various components/parts real-time transmission measurements. The second system it is also a flat panel detectors, with a size of 510 mm X 610 mm, with the detector size from 0.2 mm until 1.5 mm, which can operate by applying the dual-energy method, very useful for discriminating materials by evaluating their Atomic effective number. The high resolution and low-cost of this flat-panels widens their applicability by covering large requirements, from identifying unwanted materials within a structure until detection of very thin cracks in complex components.

  18. Digital radiography is promising in industrial testing

    International Nuclear Information System (INIS)

    Del Fabbro, F.

    2015-01-01

    Digital radiography has recently entered the industrial world as a tool for non-destructive testing. There are 3 types of digital radiography: computed radiography (CR), direct radiography (DR) and computed tomography (CT). In computed radiography, traditional silver-halide films are replaced by photostimulable phosphor imaging plates that are activated through laser scanning and digitized. Direct radiography uses a flat panel detector (FPD) composed of X-ray detectors that performs an immediate digital conversion of the image that can be read by a computer. DR is a perfect tool for industrial testing but the fragility of the FPD panels reduces its uses. Computed tomography is based on the principle of DR to get data corresponding to successive cross-section images of the object. These data are processed by a software to get a 3-dimensional image of the object. CT was first developed for medical use but requires some improvement to become more accurate, faster, particularly for big objects. In recent years DR has enjoyed the highest growth rate in digital radiography. (A.C.)

  19. Quality assurance in digital radiography

    International Nuclear Information System (INIS)

    Busch, H.P.; Lehmann, K.J.

    1989-01-01

    At present, there is no standard way of evaluating performance characteristics of digital radiography systems. Continuous measurements of performance parameters are necessary in order to obtain images of high quality. Parameters of quality assurance in digital radiography, which can be evaluated with simple, quick methods, are spatial resolution, low-contrast detectability, dynamic range and exposure dose. Spatial resolution was determined by a lead bar pattern, whereas the other parameters were measured by commercially available phantoms. Performance measurements of 10 digital subtraction angiography (DSA) units and one digital radiography system for unsubtracted digital radiography were assessed. From these results, recommendations for performance parameter levels will be discussed. (author)

  20. An overview of digital radiography

    International Nuclear Information System (INIS)

    Aweligiba, S. A.

    2013-04-01

    The medical application of radiography has gained wider study since diagnostic radiology plays a very important role in modern medicine for fast diagnosis and therapy. Digital radiography is a relatively new technology that promises greater accuracy, lesser dose and better manipulation of patient radiology images in hospitals. In this study, a general discussion on digital radiography has been presented. The presentation focuses on the optimisation of doses to patients in the medical application of digital radiography, quality control and quality assurance. A brief presentation on performance indicators in digital radiography has also been presented. The advantages of digital radiography over the conventional film/screen system have been elaborated and its limitations are also outlined. (author)

  1. On site evaluation of three flat panel detectors for digital radiography

    International Nuclear Information System (INIS)

    Borasi, Giovanni; Nitrosi, Andrea; Ferrari, Paolo; Tassoni, Davide

    2003-01-01

    During a tender we evaluated the image performance of three commercially available active matrix flat panel imagers (AMFPI) for general radiography, one based on direct detection method (Se photoconductor) the other two on indirect detection method (CsI phosphor). Basic image quality parameters (MTF, NNPS, DQE) were evaluated with particular attention to dose and energy dependence. As it is known, presampling modulation transfer function (MTF) of selenium based detector is very high (at 70 kV, 2 cycles/mm, 2.5 μGy, about 0.80). Indirect detection panels exhibit a comparable (lower) resolution (at 70 kV, 2 cycles/mm, 2.5 μGy, MTF is about 0.34 for both the systems analyzed) and a more pronounced energy and dose dependence could also be noted in one of them. As a consequence of the very high resolution, the normalized noise power spectrum (NNPS) of the direct system is substantially flat, very similar to a white noise. Considering that the sensitive layer of all detectors is the same (0.5 mm), the relatively higher NNPS values are related to selenium absorption properties (lower Z respect to CsI:Tl) and detector inherent noise. NNPSs of the other systems, at low frequencies, are comparable but the frequency dependence is significantly different. At 70 kV, 2.5 μGy, 0.5 cycles/mm detective quantum efficiency (DQE) is about 0.35 for the direct detection system, and about the same (0.6) for the indirect ones. The combined effect of additive and multiplicative noise components makes DQE dependence on dose not monotonic. DQE present a maximum for an intermediate exposure. This complex behavior may be useful to characterize the systems in terms of the monodimensional integral over the frequency of DQE (IDQE). Both visual contrast-detail experiment and the direct evaluation of the signal-to-noise ratio confirmed, at least in a qualitative way, the system performances predicted by IDQE

  2. Clinical evaluation of digital radiography based on a large-area cesium iodide-amorphous silicon flat-panel detector compared with screen-film radiography for skeletal system and abdomen

    International Nuclear Information System (INIS)

    Okamura, Terue; Tanaka, Saori; Koyama, Koichi; Norihumi, Nishida; Daikokuya, Hideo; Matsuoka, Toshiyuki; Yamada, Ryusaku; Kishimoto, Kenji; Hatagawa, Masakatsu; Kudoh, Hiroaki

    2002-01-01

    The aim of this clinical study was to compare the image quality of digital radiography using the new digital Bucky system based on a flat-panel detector with that of a conventional screen-film system for the skeletal structure and the abdomen. Fifty patients were examined using digital radiography with a flat-panel detector and screen-film systems, 25 for the skeletal structures and 25 for the abdomen. Six radiologists judged each paired image acquired under the same exposure parameters concerning three observation items for the bone and six items for the abdomen. Digital radiographic images for the bone were evaluated to be similar to screen-film images at the mean of 42.2%, to be superior at 50.2%, and to be inferior at 7.6%. Digital radiographic images for the abdomen were judged to be similar to screen-film images at the mean of 43.4%, superior at 52.4%, and inferior at 4.2%; thus, digital radiographic images were estimated to be either similar as or superior to screen-film images at over 92% for the bone and abdomen. On the statistical analysis, digital radiographic images were also judged to be preferred significantly in the most items for the bone and abdomen. In conclusion, the image quality of digital radiography with a flat-panel detector was superior to that of a screen-film system under the same exposure parameters, suggesting that dose reduction is possible with digital radiography. (orig.)

  3. Digital radiography of the chest

    International Nuclear Information System (INIS)

    Sakurai, Kenji; Hachiya, Junichi; Korenaga, Tateo; Nitatori, Toshiaki; Miyasaka, Yasuo; Furuya, Yoshiro

    1984-01-01

    Initial clinical experience in digital chest radiography utilizing photostimulable phosphor and scanning laser stimulated luminescence was reported. Image quality of conventional film/screen radiography and digital radiography was compared in 30 normal cases. Reflecting wide dynamic range of the system, improved image quality was confirmed in all 30 cases, particularly in visibility of various mediastinal structures and pulmonary vessels. High sensor sensitivity of the system enabled digital radiography to reduce radiation dose requirement significantly. Diagnostically acceptable chest images were obtained with approximately 1/5 of routine dose for conventional radiography without significant image quality degradation. Some artifact created by digital processing were mostly overcome by a routine use of simultaneous display of two different types of image processing and therefore was not an actual drawback from diagnostic standpoint. Further technical advancement of the system to be seen for digital storage, retrieval and tranceference of images. (author)

  4. Development of a novel direct X-ray detector using photoinduced discharge (PID) readout for digital radiography

    Science.gov (United States)

    Heo, D.; Jeon, S.; Kim, J.-S.; Kim, R. K.; Cha, B. K.; Moon, B. J.; Yoon, J.

    2013-02-01

    We developed a novel direct X-ray detector using photoinduced discharge (PID) readout for digital radiography. The pixel resolution is 512 × 512 with 200 μm pixel and the overall active dimensions of the X-ray imaging panel is 10.24 cm × 10.24 cm. The detector consists of an X-ray absorption layer of amorphous selenium, a charge accumulation layer of metal, and a PID readout layer of amorphous silicon. In particular, the charge accumulation is pixelated because image charges generated by X-ray should be stored pixel by pixel. Here the image charges, or holes, are recombined with electrons generated by the PID method. We used a 405 nm laser diode and cylindrical lens to make a line beam source with a width of 50 μm for PID readout, which generates charges for each pixel lines during the scan. We obtained spatial frequencies of about 1.0 lp/mm for the X-direction (lateral direction) and 0.9 lp/mm for the Y-direction (scanning direction) at 50% modulation transfer function.

  5. Development of CT and 3D-CT Using Flat Panel Detector Based Real-Time Digital Radiography System

    International Nuclear Information System (INIS)

    Ravindran, V. R.; Sreelakshmi, C.; Vibin

    2008-01-01

    The application of Digital Radiography in the Nondestructive Evaluation (NDE) of space vehicle components is a recent development in India. A Real-time DR system based on amorphous silicon Flat Panel Detector has been developed for the NDE of solid rocket motors at Rocket Propellant Plant of VSSC in a few years back. The technique has been successfully established for the nondestructive evaluation of solid rocket motors. The DR images recorded for a few solid rocket specimens are presented in the paper. The Real-time DR system is capable of generating sufficient digital X-ray image data with object rotation for the CT image reconstruction. In this paper the indigenous development of CT imaging based on the Realtime DR system for solid rocket motor is presented. Studies are also carried out to generate 3D-CT image from a set of adjacent CT images of the rocket motor. The capability of revealing the spatial location and characterisation of defect is demonstrated by the CT and 3D-CT images generated.

  6. The effect of dose reduction on image quality in digital radiography using a flat-panel detector: experimental study in rabbits

    International Nuclear Information System (INIS)

    Jung, Sung Il; Goo, Jin Mo; Lee, Hyun Ju; Moon, Woo Kyung; Lim, Kun Young; Cho, Gyung Goo; Kim, Ji Hoon; Im, Jung Gi; Choi, Jang Yong; Nam, Sang Hee

    2005-01-01

    To evaluate the effect of dose reduction on image quality in digital radiography using a flat-panel detector. Digital radiographs of 30 rabbits were obtained at two different dose levels (33.23 μGY for the standard dose group and 20.09 μGY for the reduced dose group). The amorphous selenium-based flat-panel detector system had a panel size of 7 x 8.5 inches, a matrix of 1280 x 1536 (pixels?), and a pixel pitch of 138 μm. Four observers evaluated the soft-copy images on a high-resolution video monitor (2560 x 2048 x 8 bits) in random order. The observers rated the visibility of 13 different anatomic structures on a 5-point scale, viz, the retrocardiac lung, subdiaphragmatic lung, heart border, diaphragmatic border, proximal airway, unobscured lung, liver border, kidney border, bowel gas, flank stripe, ribs, and vertebrae in the mediastinal and abdominal regions. Statistical significance was determined using Wilcoxon's signed rank test. There was no statistically significant difference in the visibility of the anatomic structures on digital radiography between the standard and reduced dose groups. Digital radiography using an amorphous selenium-based flat-panel detector can preserve the image quality, though the dose is reduced to 40% of the standard level

  7. The effect of dose reduction on image quality in digital radiography using a flat-panel detector: experimental study in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Sung Il; Goo, Jin Mo; Lee, Hyun Ju; Moon, Woo Kyung; Lim, Kun Young; Cho, Gyung Goo; Kim, Ji Hoon; Im, Jung Gi [Seoul National College of Medicine, Seoul (Korea, Republic of); Choi, Jang Yong; Nam, Sang Hee [Inje University, Seoul (Korea, Republic of)

    2005-07-15

    To evaluate the effect of dose reduction on image quality in digital radiography using a flat-panel detector. Digital radiographs of 30 rabbits were obtained at two different dose levels (33.23 {mu}GY for the standard dose group and 20.09 {mu}GY for the reduced dose group). The amorphous selenium-based flat-panel detector system had a panel size of 7 x 8.5 inches, a matrix of 1280 x 1536 (pixels?), and a pixel pitch of 138 {mu}m. Four observers evaluated the soft-copy images on a high-resolution video monitor (2560 x 2048 x 8 bits) in random order. The observers rated the visibility of 13 different anatomic structures on a 5-point scale, viz, the retrocardiac lung, subdiaphragmatic lung, heart border, diaphragmatic border, proximal airway, unobscured lung, liver border, kidney border, bowel gas, flank stripe, ribs, and vertebrae in the mediastinal and abdominal regions. Statistical significance was determined using Wilcoxon's signed rank test. There was no statistically significant difference in the visibility of the anatomic structures on digital radiography between the standard and reduced dose groups. Digital radiography using an amorphous selenium-based flat-panel detector can preserve the image quality, though the dose is reduced to 40% of the standard level.

  8. Digital detection systems for projection radiography

    International Nuclear Information System (INIS)

    Schulz, R.F.

    2001-01-01

    This article gives a survey of digital X-ray detection systems for projection radiography. The different principles are compared and some general characteristics are derived. The basic conversion mechanisms in the absorption layers are described. The basic principles of solid state X-ray detectors and their general characteristics are elucidated as well as some similarities with detectors for computed tomography. Some important application and system aspects are considered. An outlook on further possible developments in this field is given. (orig.) [de

  9. Digital radiography of the skeleton using a large-area detector based on amorphous silicon technology: Image quality and potential for dose reduction in comparison with screen-film radiography

    International Nuclear Information System (INIS)

    Volk, M.; Strotzer, M.; Holzkneckt, N.; Manke, C.; Lenhart, M.; Gmeinwieser, J.; Link, J.; Reiser, M.; Feuerback, S.

    2000-01-01

    AIM: The purpose of this study was to evaluate a large-area, flat-panel X-ray detector (FD), based on caesium-iodide (CsI) and amorphous silicon (a-Si) with respect to skeletal radiography. Conventional images were compared with digital radiographs using identical and reduced radiation doses. MATERIALS AND METHODS: Thirty consecutive patients were studied prospectively using conventional screen-film radiography (SFR; detector dose 2.5 μGy). Digital images were taken from the same patients with detector doses of 2.5, 1.25 and 0.625 μGy, respectively. The active-matrix detector had a panel size of 43 x 43 cm, a matrix of 3 x 3K, and a pixel size of 143 μm. All hard copies were presented in a random order to eight independent observers, who rated image quality according to subjective quality criteria. Results were assessed for significance using the Student's t -test (confidence level 95%). RESULTS: A statistically significant preference for digital over conventional images was revealed for all quality criteria, except for over-exposure (detector dose 2.5 μGy). Digital images with a 50% dose showed a small, statistically not significant, inferiority compared with SFR. The FD-technique was significantly inferior to SFR at 75% dose reduction regarding bone cortex and trabecula, contrast and overall impression. No statistically significant differences were found with regard to over- and under-exposure and soft tissue presentation. CONCLUSION: Amorphous silicon-based digital radiography yields good image quality. The potential for dose reduction depends on the clinical query. Volk, M. (2000)

  10. Image quality in digital radiography

    International Nuclear Information System (INIS)

    Kuhn, H.

    1986-01-01

    The contribution deals with the potentials of digital radiography and critically evaluates the advantages of drawbacks of the image intensifier-tv-digital system; digitalisation of the X-ray film and scanning of luminescent storage foils. The evaluation is done in comparison with the image quality of the traditional, large-size X-ray picture. (orig.) [de

  11. Digital Radiography in Kenya today

    International Nuclear Information System (INIS)

    Omenta, E.N.

    2006-01-01

    Its nearly one year and a half since digital imaging/radiography was introduced in Kenya mainly in Nairobi. the technology is becoming an increasingly effective and acceptable modality of producing radiographs from the traditional conventional radiography in use to date. the digital radiography offers numerous advantages that have been noted for the short period over the conventional way. For instance radiographs are produced in real time (less than 3 minutes), by so doing the technology has eliminated the wait for the processing period. the radiation exposure to the patient under the radiological examination is reduced as much as 90% from the traditional conventional film taking. The cost, labour and record-keeping necessary to maintain a chemical processor and darkroom operations are as well eliminated. The cost of purchasing and disposing of film wastes/darkroom processing chemicals, which are environmentally hazardous, also become unnecessary.digital radiography technology makes the digital images comparable to other images on the screen at that instant making both the patient and the clinician easily access images when needed. digital receptors have also replaced the cassette containing intensifying screens and film that is used in conventional radiography

  12. Exploration of exposure conditions with a novel wireless detector for bedside digital radiography

    Science.gov (United States)

    Bosmans, Hilde; Nens, Joris; Delzenne, Louis; Marshall, Nicholas; Pauwels, Herman; De Wever, Walter; Oyen, Raymond

    2012-03-01

    We propose, apply and validate an optimization scheme for a new wireless CsI based DR detector in combination with a regular mobile X-ray system for bedside imaging applications. Three different grids were tested in this combination. Signal-difference-to-noise was investigated in two ways, using a 1mm Cu piece in combination with different thicknesses of PMMA and by means of the CDRAD phantom using 10 images per condition and an automated evaluation method. A Figure of Merit (FOM), namely SDNR2/Imparted Energy, was calculated for a large range of exposure conditions, without and with grid in place. Misalignment of the grids was evaluated via the same FOMs. This optimization study was validated with comparative X-ray acquisitions performed on dead bodies. An experienced radiologist scored the quality of several specific aspects for all these exposures. Signal difference to noise ratios measured with the Cu method correlated well with the threshold contrasts from the CDRAD analysis (R2 > 0.9). The analysis showed optimal FOM with detector air kerma rates as typically used in clinical practice. Lower tube voltages provide higher FOM than the higher values but their practical use depends on the limitations of X-ray tubes, linked to patient motion artefacts. The use of high resolution grids should be encouraged, as the FOM increases with 47% at 75kV. These scores from the Visual grading study confirmed the results obtained with the FOM. The switch to (wireless) DR technology for bedside imaging could benefit from devices to improve grid positioning or any scatter reduction technique.

  13. Contrast-detail analysis of three flat panel detectors for digital radiography

    International Nuclear Information System (INIS)

    Borasi, Giovanni; Samei, Ehsan; Bertolini, Marco; Nitrosi, Andrea; Tassoni, Davide

    2006-01-01

    In this paper we performed a contrast detail analysis of three commercially available flat panel detectors, two based on the indirect detection mechanism (GE Revolution XQ/i, system A, and Trixell/Philips Pixium 4600, system B) and one based on the direct detection mechanism (Hologic DirectRay DR 1000, system C). The experiment was conducted using standard x-ray radiation quality and a widely used contrast-detail phantom. Images were evaluated using a four alternative forced choice paradigm on a diagnostic-quality softcopy monitor. At the low and intermediate exposures, systems A and B gave equivalent performances. At the high dose levels, system A performed better than system B in the entire range of target sizes, even though the pixel size of system A was about 40% larger than that of system B. At all the dose levels, the performances of the system C (direct system) were lower than those of system A and B (indirect systems). Theoretical analyses based on the Perception Statistical Model gave similar predicted SNR T values corresponding to an observer efficiency of about 0.08 for systems A and B and 0.05 for system C

  14. Image Acquisition and Quality in Digital Radiography.

    Science.gov (United States)

    Alexander, Shannon

    2016-09-01

    Medical imaging has undergone dramatic changes and technological breakthroughs since the introduction of digital radiography. This article presents information on the development of digital radiography and types of digital radiography systems. Aspects of image quality and radiation exposure control are highlighted as well. In addition, the article includes related workplace changes and medicolegal considerations in the digital radiography environment. ©2016 American Society of Radiologic Technologists.

  15. Digital chest radiography

    DEFF Research Database (Denmark)

    Debess, Jeanne Elisabeth; Vejle-Sørensen, Jens Kristian; Thomsen, Henrik

    ,3 mAs and SID SID of 180 centimetres using a phantom and lithium fluoride thermo luminescence dosimeter (TLD). Dose to risk organs mamma, thyroid and colon are measured at different collimations with one-centimetre steps. TLD results are used to estimate dose reduction for different collimations...... at the conference. Conclusion: Collimation improvement in basic chest radiography can reduce the radiation to female patients at chest x-ray examinations....

  16. Digital radiography: description and user's guide

    International Nuclear Information System (INIS)

    Berthel, A.; Bonin, Th.; Cadilhon, S.; Thiery, Ch.; Chatellier, L.; Kaftandjian, V.; Honorat, Ph.; Torrent, J.; Le Brun, A.; Maglaive, J.C.; Moreau, Ph.; Pettier, J.L.; Rebuffel, V.; Roenelle, P.; Roussilhe, J.; Staat, St.; Tahon, M.

    2007-01-01

    The presented document arises from the work of the group 'Digital Radiography and sensors' of COFREND. It is a collective work of synthesis aimed to analyze the quality parameters of digital images influencing the answer and the diagnosis brought to a given industrial problem. Five families of digital sensors have been studied: 1. Image Intensifier coupled with CCD devices - 2. scintillators coupled with a CCD device- 3. Flat Panels with indirect conversion - 4. Flat Panels with direct electric conversion - 5. Photostimulable Storage Phosphor Screens). In particular, concerning a complete imaging chain, it deals with the notions of magnification, blur (unsharpness) (geometrical, kinetic or internal to the very sensor), noises, scattered radiation, spatial resolution, which is different from the one of analog detectors such as films, Contrast to Noise Ratio (CNR), sensitivity using IQIs, dynamic range, detection quantum efficiency, persistence and temporal resolution. This document is not a standard; it must be understood as a user's guide, and it approaches some essentials corrections to bring to a sensor in order to optimize his efficiency without losing information during the pre-processing phase in the radiographic acquisition. It also introduces some image processing tools commonly used. It can be used as a source document to the future elaboration of a standardisation document. It augurs not at all of the choice of a digital sensor with regard to the traditional radiographic film, but gives bases of reflection to a radio user for a sensible transfer from the classic radiography to the digital radiography. (authors)

  17. Digital radiography with a large-scale electronic flat-panel detector vs screen-film radiography: observer preference in clinical skeletal diagnostics

    International Nuclear Information System (INIS)

    Hamers, S.; Freyschmidt, J.; Neitzel, U.

    2001-01-01

    The imaging performance of a recently developed digital flat-panel detector system was compared with conventional screen-film imaging in an observer preference study. In total, 34 image pairs of various regions of the skeleton were obtained in 24 patients; 30 image pairs were included in the study. The conventional images were acquired with 250- and 400-speed screen-film combinations, using the standard technique of our department. Within hours, the digital images were obtained using identical exposure parameters. The digital system employed a large-area (43 x 43 cm) flat-panel detector based on amorphous silicon (Trixell Pixium 4600), integrated in a Bucky table. Six radiologists independently evaluated the image pairs with respect to image latitude, soft tissue rendition, rendition of the periosteal and enosteal border of cortical bone, rendition of cancellous bone and the visibility of potentially present pathological changes, using a subjective five-point scale. The digital images were rated significantly (p=0.001) better than the screen-film images with respect to soft tissue rendition and image latitude. Also the rendition of the cancellous bone and the periosteal and enosteal border of the cortical bone was rated significantly (p=0.05) better for the flat-panel detector. The visibility of pathological lesions was equivalent; only large-area sclerotic lesions (n=2) were seen superiorly on screen-film images. The new digital flat-panel detector based on amorphous silicon appears to be at least equivalent to conventional screen-film combinations for skeletal examinations, and in most respects even superior. (orig.)

  18. Investigation of physical imaging properties in various digital radiography systems

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hoi Woun [Dept. of Radiological Science, Baekseok Culture University, Cheonan (Korea, Republic of); Min, Jung Hwan [Dept. of Radiological technology, Shingu University, Seongnam (Korea, Republic of); Yoon, Yong Su [Dept. of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Kyushu (Japan); Kim, Jung Min [Dept. of Health and Environmental Science, College of Health Science, Korea University, Seoul (Korea, Republic of)

    2017-09-15

    We aimed to evaluate the physical imaging properties in various digital radiography systems with charged coupled device (CCD), computed radiography (CR), and indirect flat panel detector (FPD). The imaging properties measured in this study were modulation transfer function (MTF) wiener spectrum (WS), and detective quantum efficiency (DQE) to compare the performance of each digital radiography system. The system response of CCD were in a linear relationship with exposure and that of CR and FPD were proportional to the logarithm of exposure. The MTF of both CR and FPD indicated a similar tendency but in case of CCD, it showed lower MTF than that of CR and FPD. FPD showed the lowest WS and also indicated the highest DQE among three systems. According to the results, digital radiography system with different type of image receptor had its own image characteristics. Therefore, it is important to know the physical imaging characteristics of the digital radiography system accurately to obtain proper image quality.

  19. Dose efficiency and low-contrast detectability of an amorphous silicon x-ray detector for digital radiography

    International Nuclear Information System (INIS)

    Aufrichtig, Richard

    2000-01-01

    The effect of dose reduction on low-contrast detectability is investigated theoretically and experimentally for a production grade amorphous silicon (a-Si) x-ray detector and compared with a standard thoracic screen-film combination. A non-prewhitening matched filter observer model modified to include a spatial response function and internal noise for the human visual system (HVS) is used to calculate a signal-to-noise ratio (SNR) related to object detectability. Other inputs to the SNR calculation are the detective quantum efficiency (DQE) and the modulation transfer function (MTF) of the imaging system. Besides threshold detectability, the model predicts the equivalent perception dose ratio (EPDR), which is the fraction of the screen-film exposure for which the digital detector provides equal detectability. Images of a contrast-detail phantom are obtained with the digital detector at dose levels corresponding to 27%, 41%, 63% and 100% of the dose used for screen-film. The images are used in a four-alternative forced choice (4-AFC) observer perception study in order to measure threshold detectability. A statistically significant improvement in contrast detectability is measured with the digital detector at 100% and 63% of the screen-film dose. There is no statistical difference between screen-film and digital at 41% of the dose. On average, the experimental EPDR is 44%, which agrees well with the model prediction of 40%. (author)

  20. Development of Portable Digital Radiography System with a Device for Monitoring X-ray Source-Detector Angle and Its Application in Chest Imaging

    Directory of Open Access Journals (Sweden)

    Tae-Hoon Kim

    2017-03-01

    Full Text Available This study developed a device measuring the X-ray source-detector angle (SDA and evaluated the imaging performance for diagnosing chest images. The SDA device consisted of Arduino, an accelerometer and gyro sensor, and a Bluetooth module. The SDA values were compared with the values of a digital angle meter. The performance of the portable digital radiography (PDR was evaluated using the signal-to-noise (SNR, contrast-to-noise ratio (CNR, spatial resolution, distortion and entrance surface dose (ESD. According to different angle degrees, five anatomical landmarks were assessed using a five-point scale. The mean SNR and CNR were 182.47 and 141.43. The spatial resolution and ESD were 3.17 lp/mm (157 μm and 0.266 mGy. The angle values of the SDA device were not significantly difference as compared to those of the digital angle meter. In chest imaging, the SNR and CNR values were not significantly different according to the different angle degrees. The visibility scores of the border of the heart, the fifth rib and the scapula showed significant differences according to different angles (p < 0.05, whereas the scores of the clavicle and first rib were not significant. It is noticeable that the increase in the SDA degree was consistent with the increases of the distortion and visibility score. The proposed PDR with a SDA device would be useful for application in the clinical radiography setting according to the standard radiography guidelines.

  1. Digital luminecence radiography

    International Nuclear Information System (INIS)

    Erlemann, R.; Adolph, J.M.G.; Reuther, G.; Wiesmann, W.; Fervers, J.; Vestring, T.; Roos, N.; Peters, P.E.

    1990-01-01

    This paper reports on the value of contrast post processing with DLR (2.5 lp/mm; gray-scale, 10 bit) evaluated in myelography (decision making depends more on image contrast than on spatial resolution). DLR was compared with conventional myelography by means of ROC methodology. Ninety-five conventional (CR), digital (DR), and edge- enhanced digital (EDR) myelographic images (49 disk herniations, 46 normal) were read independently by five board-certified radiologists with no clinical information. Findings were scored using a 5-point confidence-scale, and an ROC analysis was performed based on CT-myelography as the gold standard

  2. Fluoroscopic digital radiography

    International Nuclear Information System (INIS)

    Hynes, D.M.; Rowlands, J.A.; Edmonds, E.W.; Porter, A.J.; Toth, B.D.

    1987-01-01

    The authors have been working with three different developmental systems, exploring the clinical benefits of digital recording of the fluoroscopic image. This educational exhibit describes the components of such systems and emphasizes the strengths and weaknesses of each. Specific technical reference is made to the image intensifier, TV camera, 1,024/sup 2/ image store, hard copy devices, and the mechanics of operation in the general fluoroscopic environment. All observations indicate that the problems of resolution, motion blur, noise, field size, and dose can be solved. The findings are supported by clinical examples

  3. System for uncollimated digital radiography

    Science.gov (United States)

    Wang, Han; Hall, James M.; McCarrick, James F.; Tang, Vincent

    2015-08-11

    The inversion algorithm based on the maximum entropy method (MEM) removes unwanted effects in high energy imaging resulting from an uncollimated source interacting with a finitely thick scintillator. The algorithm takes as input the image from the thick scintillator (TS) and the radiography setup geometry. The algorithm then outputs a restored image which appears as if taken with an infinitesimally thin scintillator (ITS). Inversion is accomplished by numerically generating a probabilistic model relating the ITS image to the TS image and then inverting this model on the TS image through MEM. This reconstruction technique can reduce the exposure time or the required source intensity without undesirable object blurring on the image by allowing the use of both thicker scintillators with higher efficiencies and closer source-to-detector distances to maximize incident radiation flux. The technique is applicable in radiographic applications including fast neutron, high-energy gamma and x-ray radiography using thick scintillators.

  4. High resolution radiography of ambers with pixel detectors

    Czech Academy of Sciences Publication Activity Database

    Dammer, J.; Weyda, F.; Beneš, J.; Sopko, V.; Jandejsek, I.; Pflegerová, Jitka

    2013-01-01

    Roč. 8, č. 3 (2013), C03024 ISSN 1748-0221. [Conference: International Workshop on Radiation Imaging Detectors /14./. Figueira da Foz, 01.07.2012-05.07.2012] Grant - others:GA ČR(CZ) GA103/09/2101; GA Mšk(CZ) LA08032 Program:GA; LA Institutional support: RVO:60077344 Keywords : X-ray detectors * Inspection with x-rays * X-ray radiography and digital radiography (DR) Subject RIV: EA - Cell Biology Impact factor: 1.526, year: 2013 http://iopscience.iop.org/1748-0221/8/03/C03024/

  5. Digital and analogue industrial radiography, application fields

    International Nuclear Information System (INIS)

    Willems, Peter; Millord, Erik Yardin

    2000-01-01

    Full text: Reusable phosphor screens for computer radiography (CR), amorphous selenium screens for direct radiography (DR), film digitalisation (FD) constitute imaging methods accepted by industry and are used for non-destructive radiographic testing (RT). Economic pressures are involving and affecting digital RT technology. Standards and codes for film radiography and radioscopy qualification do no longer cover the wide range of digital RT applications. It will be our task to optimise the performance of digital RT characterisation and to create appropriate examination methods to use all these new and existent technologies. In the meantime, an increasing automation and control of manual methods of analogue radiography can as well be expected. (author)

  6. Digital radiography: study of an alternative technique to conventional radiography

    International Nuclear Information System (INIS)

    Banchet, J.; Tisseur, D.; Thomas, A.

    2009-01-01

    Digital radiography, already in use in many industrial applications, appears as a potential alternative technique to conventional radiography in the nuclear field (and more especially to the inspection of welded joints). The advantages of digital radiography are a reduced explosion risk (due to the use of lower energy and activity sources), a lower installation time, a reduced exclusion zone, and the absence of effluents. However, to the contrary of the US case, this technique may not be used in France as it is not referenced in the regulating codes (RCCM, etc.). Areva has launched a R and D study in order to characterize the equivalencies between digital and conventional radiography. First results of this study are given

  7. Better imaging: the advantages of digital radiography

    NARCIS (Netherlands)

    van der Stelt, P.F.

    2008-01-01

    Background. Digital radiography has been available in dentistry for more than 25 years, but it has not replaced conventional film-based radiography completely. This could be because of the costs involved in replacing conventional radiographic equipment with a digital imaging system, or because

  8. Digital radiography and caries diagnosis.

    Science.gov (United States)

    Wenzel, A

    1998-01-01

    Direct digital acquisition of intra-oral radiographs has been possible only in the last decade. Several studies have shown that, theoretically, there are a number of advantages of direct digital radiography compared with conventional film. Laboratory as well as controlled clinical studies are needed to determine whether new digital imaging systems alter diagnosis, treatment and prognosis compared with conventional methods. Most studies so far have evaluated their diagnostic performance only in laboratory settings. This review concentrates on what evidence we have for the diagnostic efficacy of digital systems for caries detection. Digital systems are compared with film and those studies which have evaluated the effects on diagnostic accuracy of contrast and edge enhancement, image size, variations in radiation dose and image compression are reviewed together with the use of automated image analysis for caries diagnosis. Digital intra-oral radiographic systems seem to be as accurate as the currently available dental films for the detection of caries. Sensitivities are relatively high (0.6-0.8) for detection of occlusal lesions into dentine with false positive fractions of 5-10%. A radiolucency in dentine is recognised as a good predictor for demineralisation. Radiography is of no value for the detection of initial (enamel) occlusal lesions. For detection of approximal dentinal lesions, sensitivities, specificities as well as the predictive values are fair, but are very poor for lesions known to be confined to enamel. Very little documented information exists, however, on the utilization of digital systems in the clinic. It is not known whether dose is actually reduced with the storage phosphor system, or whether collimator size is adjusted to fit sensor size in the CCD-based systems. There is no evidence that the number of retakes have been reduced. It is not known how many images are needed with the various CCD systems when compared with a conventional bitewing

  9. Examination of welds by digital radiography

    International Nuclear Information System (INIS)

    Ekinci, S.

    2004-01-01

    Industrial radiography is the oldest and most reliable non-destructive test method in the examination and two dimensional evaluation of weld defects. Digital radiographic methods provide more sensitive, faster and more reliable evaluation of defect images. One of the most important factors influencing the contrast and consequently the image quality is the noise on the film caused by scattered radiation. The digital image processing technique can eliminate the noise and improve the image quality. Digital radiography also enables three dimensional evaluation of weld defects. This work describes the use of digital radiography in the evaluation of defects in welds of different configurations by using a laser film digitizing system and an appropriate software programme. Advantages and limitations of the digital technique and conventional film radiography were discussed. (author)

  10. Examination of welds by digital radiography

    International Nuclear Information System (INIS)

    Ekinci, S.

    2004-01-01

    Full text: Industrial radiography is the oldest and most reliable non-destructive test method in the examination and two dimensional evaluation of weld defects. Digital radiographic methods provide more sensitive, faster and more reliable evaluation of defect images. One of the most important factors influencing the contrast and consequently the image quality is the noise on the film caused by scattered radiation. The digital image processing technique can eliminate the noise and improve the image quality. Digital radiography also enables three dimensional evaluation of weld defects. This work describes the use of digital radiography in the evaluation of defects in welds of different configurations by using a laser film digitizing system and an appropriate software programme. Advantages and limitations of the digital technique and conventional film radiography were discussed

  11. Optimizing digital radiography of children

    International Nuclear Information System (INIS)

    Willis, Charles E.

    2009-01-01

    Pediatric projection imaging differs from imaging of the adult patient. Children are smaller, more radiosensitive, and less compliant than their adult counterparts. Their characteristics affect the way projection imaging is practiced and how dose is optimized. Computed radiography (CR) and digital radiography (DR) have been embraced by pediatric practitioners in order to reduce dose and improve image quality. Unfortunately, dose optimization with CR and DR has been hampered by a lack of definition of appropriate exposure levels, a lack of standardization in exposure factor feedback, and a lack of understanding of the fundamentals of CR and DR technology. The potential for over-exposure exists with both CR and DR. Both the Society for Pediatric Radiology and the American Association of Physicists in Medicine recognize the promise and shortcomings of CR and DR technology and have taken steps to join with manufacturers in improving the practice of CR and DR imaging. Although the risks inherent in pediatric projection imaging with CR and DR are low, efforts to reduce dose are worthwhile, so long as diagnostic quality is maintained. Long-standing recommendations for limiting radiation dose in pediatric projection imaging are still applicable to CR and DR.

  12. Digital radiography of the chest in pediatric patients

    International Nuclear Information System (INIS)

    Puig, S.

    2003-01-01

    The hopes placed in digital radiography have been fulfilled only partly in pediatric radiology. Specifically, the option of gaining reduced radiation exposure in combination with a similar or even improved image quality was hard to realize. The only portable digital system available for a long time were storage phosphors which were disadvantaged by an extremely limited dose-quantum-efficiency (DQE) in comparison to digital flat panel detectors. New developments and the introduction of the dual-reading system led to image qualities comparable to film-screen-systems with high resolution and achievable without dose increase, sometimes even with dose reduction. A study using an animal model suggests that these systems can even be used in preterm infants with very low birth weights. A new portable flat panel detector by Canon may improve digital chest radiography in pediatric patients. (orig.) [de

  13. Digital radiography exposure indices: A review

    International Nuclear Information System (INIS)

    Mothiram, Ursula; Brennan, Patrick C; Lewis, Sarah J; Moran, Bernadette; Robinson, John

    2014-01-01

    Digital radiography (DR) technologies have the advantage of a wide dynamic range compared to their film-screen predecessors, however, this poses a potential for increased patient exposure if left unchecked. Manufacturers have developed the exposure index (EI) to counter this, which provides radiographers with feedback on the exposure reaching the detector. As these EIs were manufacturer-specific, a wide variety of EIs existed. To offset this, the international standardised EI has been developed by the International Electrotechnical Commission (IEC) and the American Association of Physicists in Medicine (AAPM). The purpose of this article is to explore the current literature relating to EIs, beginning with the historical development of the EI, the development of the standardised EI and an exploration of common themes and studies as evidenced in the research literature. It is anticipated that this review will provide radiographers with a useful guide to understanding EIs, their application in clinical practice, limitations and suggestions for further research

  14. Portable Digital Radiography and Computed Tomography Manual

    Energy Technology Data Exchange (ETDEWEB)

    2007-11-01

    This user manual describes the function and use of the portable digital radiography and computed tomography (DRCT) scanner. The manual gives a general overview of x-ray imaging systems along with a description of the DRCT system. An inventory of the all the system components, organized by shipping container, is also included. In addition, detailed, step-by-step procedures are provided for all of the exercises necessary for a novice user to successfully collect digital radiographs and tomographic images of an object, including instructions on system assembly and detector calibration and system alignment. There is also a short section covering the limited system care and maintenance needs. Descriptions of the included software packages, the DRCT Digital Imager used for system operation, and the DRCT Image Processing Interface used for image viewing and tomographic data reconstruction are given in the appendixes. The appendixes also include a cheat sheet for more experienced users, a listing of known system problems and how to mitigate them, and an inventory check-off sheet suitable for copying and including with the machine for shipment purposes.

  15. Digital chest radiography with an amorphous silicon flat-panel-detector versus a storage-phosphor system: comparison of soft-copy images

    International Nuclear Information System (INIS)

    Lee, Hyun Ju; Im, Jung Gi; Goo, Jin Mo; Lee, Chang Hyun

    2006-01-01

    We compared the soft-copy images produced by an amorphous silicon flat-panel-detector system with the images produced by a storage-phosphor radiography system for their ability to visualize anatomic regions of the chest. Two chest radiologists independently analyzed 234 posteroanterior chest radiographs obtained from 78 patients on high-resolution liquid crystal display monitors (2560 x 2048 x 8 bits). In each patient, one radiograph was obtained with a storage-phosphor system, and two radiographs were obtained via amorphous silicon flat-panel-detector radiography with and without spatial frequency filtering. After randomizing the 234 images, the interpreters rated the visibility and radiographic quality of 11 different anatomic regions. Each image was ranked on a five-point scale (1 = not visualized, 2 = poor visualization, 3 = fair visualization, 4 = good visualization, and 5 = excellent visualization). The statistical difference between each system was determined using the Wilcoxon's signed rank test. The visibility of three anatomic regions (hilum, heart border and ribs), as determined by the chest radiologist with 14 years experience (ρ < 0.05) and the visibility of the thoracic spine, as determined by the chest radiologist with 8 years experience (ρ = 0.036), on the amorphous silicon flat-panel-detector radiography prior to spatial frequency filtering were significantly superior to that on the storage-phosphor radiography. The visibility of 11 anatomic regions, as determined by the chest radiologist with 14 years experience (ρ < 0.0001) and the visibility of five anatomic regions (unobscured lung, rib, proximal airway, thoracic spine and overall appearance), as determined by the chest radiologist with 8 years experience (ρ < 0.05), on the amorphous silicon flat-panel-detector radiography after spatial frequency filtering were significantly superior to that on the storage-phosphor radiography. The amorphous silicon flat-panel-detector system depicted the

  16. Digital image processing in neutron radiography

    International Nuclear Information System (INIS)

    Koerner, S.

    2000-11-01

    Neutron radiography is a method for the visualization of the macroscopic inner-structure and material distributions of various samples. The basic experimental arrangement consists of a neutron source, a collimator functioning as beam formatting assembly and of a plane position sensitive integrating detector. The object is placed between the collimator exit and the detector, which records a two dimensional image. This image contains information about the composition and structure of the sample-interior, as a result of the interaction of neutrons by penetrating matter. Due to rapid developments of detector and computer technology as well as deployments in the field of digital image processing, new technologies are nowadays available which have the potential to improve the performance of neutron radiographic investigations enormously. Therefore, the aim of this work was to develop a state-of-the art digital imaging device, suitable for the two neutron radiography stations located at the 250 kW TRIGA Mark II reactor at the Atominstitut der Oesterreichischen Universitaeten and furthermore, to identify and develop two and three dimensional digital image processing methods suitable for neutron radiographic and tomographic applications, and to implement and optimize them within data processing strategies. The first step was the development of a new imaging device fulfilling the requirements of a high reproducibility, easy handling, high spatial resolution, a large dynamic range, high efficiency and a good linearity. The detector output should be inherently digitized. The key components of the detector system selected on the basis of these requirements consist of a neutron sensitive scintillator screen, a CCD-camera and a mirror to reflect the light emitted by the scintillator to the CCD-camera. This detector design enables to place the camera out of the direct neutron beam. The whole assembly is placed in a light shielded aluminum box. The camera is controlled by a

  17. Digital image processing in neutron radiography

    International Nuclear Information System (INIS)

    Koerner, S.

    2000-11-01

    Neutron radiography is a method for the visualization of the macroscopic inner-structure and material distributions of various materials. The basic experimental arrangement consists of a neutron source, a collimator functioning as beam formatting assembly and of a plane position sensitive integrating detector. The object is placed between the collimator exit and the detector, which records a two dimensional image. This image contains information about the composition and structure of the sample-interior, as a result of the interaction of neutrons by penetrating matter. Due to rapid developments of detector and computer technology as well as deployments in the field of digital image processing, new technologies are nowadays available which have the potential to improve the performance of neutron radiographic investigations enormously. Therefore, the aim of this work was to develop a state-of-the art digital imaging device, suitable for the two neutron radiography stations located at the 250 kW TRIGA Mark II reactor at the Atominstitut der Oesterreichischen Universitaeten and furthermore, to identify and develop two and three dimensional digital image processing methods suitable for neutron radiographic and tomographic applications, and to implement and optimize them within data processing strategies. The first step was the development of a new imaging device fulfilling the requirements of a high reproducibility, easy handling, high spatial resolution, a large dynamic range, high efficiency and a good linearity. The detector output should be inherently digitized. The key components of the detector system selected on the basis of these requirements consist of a neutron sensitive scintillator screen, a CCD-camera and a mirror to reflect the light emitted by the scintillator to the CCD-camera. This detector design enables to place the camera out of the direct neutron beam. The whole assembly is placed in a light shielded aluminum box. The camera is controlled by a

  18. Initial experiences in clinical application of the THORAX-FD: flat-panel detector radiography in thoracic diagnosis

    International Nuclear Information System (INIS)

    Herrmann, K.A.; Staebler, A.; Bonel, H.; Kulinna, C.; Holzknecht, N.; Reiser, M.F.; Geiger, B.; Boehm, S.; Maschke, M.

    2000-01-01

    The flat-panel detector closes the gap between radiography and the digital diagnostics equipment currently in use. In addition to the dose reduction that can be expected, the availability of diagnostic information in digital form enables the user to optimize the clinical workflow and to network radiography directly with a digital archiving and communication system. (orig.)

  19. Digital luminescent radiography: A substitute for conventional chest radiography?

    International Nuclear Information System (INIS)

    Neufang, K.F.R.; Krug, B.; Lorenz, R.; Steinbrich, W.

    1990-01-01

    The image quality of digital luminescent radiography (DLR) is sufficient for routine biplane chest radiography and for follow-up studies of heart size, pulmonary congestion, coin lesions, infiltrations, atelectasis, pleural effusions, and mediastinal and hilar lymph node enlargement. Chest radiography in the intensive care unit may in most cases be performed using the DLR technique. there is no need for repeat shots because of incorrect exposure, and the position of catheters, tubes, pacemakers, drains and artificial heart valves, the mediastinum, and the retrocardiac areas of the left lung are more confidently assessed on the edge-enhanced DLR films than on conventional films. Nevertheless, DLR is somewhat inferior to conventional film-screen radiography of the chest as it can demonstrate or rule out subtle pulmonary interstitial disease less confidently. There is no reduction of radiation exposure of the chest in DLR compared with modern film-screen systems. As a consequence, DLR is presently not in a position to replace traditional film-screen radiography of the chest completely. (orig.) [de

  20. Direct digital radiography versus storage phosphor radiography in the detection of wrist fractures

    Energy Technology Data Exchange (ETDEWEB)

    Peer, Siegfried; Neitzel, Ulrich; Giacomuzzi, Salvatore M.; Pechlaner, Sigurd; KUenzel, Karl Heinz; Peer, Regina; Gassner, Eva; Steingruber, Iris; Gaber, O.; Jaschke, Werner

    2002-04-01

    AIM: To define the value of digital radiography with a clinical flat panel detector system for evaluation of wrist fractures in comparison with state of the art storage phosphor radiography. MATERIAL AND METHODS: Hard copy images of 26 fractured wrist specimens were acquired with the same exposure dose on a state of the art storage phosphor radiography system and a clinical flat panel detector. Image features like cortical bone surface, trabecular bone, soft tissues and fracture delineation were independently analysed by 4 observers using a standardised protocol. Image quality ratings were evaluated with an analysis of variance (ANOVA). RESULTS: Flat panel detector radiographs were rated superior with respect to cortical and trabecular bone representation as well as fracture evaluation, while storage phosphor radiographs produced better soft tissue detail. CONCLUSION: In some of the observed image quality aspects, the performance of caesium iodide/amorphous silicon flat panel detector exceeds state of the art storage phosphor radiography. This makes it well suited for skeletal imaging particularly in trauma as seen in the detection of wrist fractures. Peer, S. et al. (2002)

  1. Direct digital radiography versus storage phosphor radiography in the detection of wrist fractures

    International Nuclear Information System (INIS)

    Peer, Siegfried; Neitzel, Ulrich; Giacomuzzi, Salvatore M.; Pechlaner, Sigurd; KUenzel, Karl Heinz; Peer, Regina; Gassner, Eva; Steingruber, Iris; Gaber, O.; Jaschke, Werner

    2002-01-01

    AIM: To define the value of digital radiography with a clinical flat panel detector system for evaluation of wrist fractures in comparison with state of the art storage phosphor radiography. MATERIAL AND METHODS: Hard copy images of 26 fractured wrist specimens were acquired with the same exposure dose on a state of the art storage phosphor radiography system and a clinical flat panel detector. Image features like cortical bone surface, trabecular bone, soft tissues and fracture delineation were independently analysed by 4 observers using a standardised protocol. Image quality ratings were evaluated with an analysis of variance (ANOVA). RESULTS: Flat panel detector radiographs were rated superior with respect to cortical and trabecular bone representation as well as fracture evaluation, while storage phosphor radiographs produced better soft tissue detail. CONCLUSION: In some of the observed image quality aspects, the performance of caesium iodide/amorphous silicon flat panel detector exceeds state of the art storage phosphor radiography. This makes it well suited for skeletal imaging particularly in trauma as seen in the detection of wrist fractures. Peer, S. et al. (2002)

  2. Problems associated with digital luminescence radiography in the neonate and young infant. Problems with digital radiography.

    Science.gov (United States)

    Arthur, R J; Pease, J N

    1992-01-01

    An evaluation of the Siemens Digiscan has been undertaken to determine whether digital luminescence radiography (DLR) could replace conventional radiography in the examination of the neonate and young infant. Whilst the overall image quality of the digital radiograph was consistently higher than for conventional radiography the difference was less marked than we had expected. Furthermore, the potential for reduction in radiation dose by reducing the repeat rate due to incorrect exposure was limited. The potential advantages of DLR have been critically examined in relationship to neonatal radiography and a number of problems encountered during the evaluation have been highlighted.

  3. Digital radiography: a survey of pediatric dentists.

    Science.gov (United States)

    Russo, Julie M; Russo, James A; Guelmann, Marcio

    2006-01-01

    The purpose of this study was to: (1) determine the popularity of digital radiography among members of the American Academy of Pediatric Dentistry (AAPD); and (2) report the most common systems in use. An AAPD-approved, voluntary, and anonymous electronic survey was developed and sent to 923 board certified pediatric dentists. Years in practice and in-office x-ray technology (digital or conventional) were inquired about initially. If negative for the use of digital radiography, future consideration for converting to digital radiography was ascertained. For positive responses, more in-depth information was requested. Information on type of system (sensor or phosphor plate), user friendliness, diagnostic ability, patient's comfort, general costs, durability, and parental and overall satisfaction was collected. For most of the questions, a 5-point assessment scale was used. Opportunity for additional comments was provided upon survey completion. Data was analyzed using descriptive statistics. A 32% (296/923) response rate was obtained. Twenty-six percent of practitioners (78/296) implemented digital radiography in their practices, whereas 71% considered future acquisition. Similar distribution for sensor and phosphor plate users was found. Sensor technology was reported to produce faster images, but was less tolerable by young children due to size and thickness. Phosphor plates were considered more children friendly, less expensive, and less durable. Parental satisfaction was very high with great marketing value. Picture quality was comparable to conventional film. Overall, digital radiography users would recommend it to other pediatric dentists. Digital radiography is not yet popular among pediatric dentists. Cost reduction and technology advancement may enhance utilization.

  4. Advantages of digital radiography: The DSI system

    International Nuclear Information System (INIS)

    Drouillard, J.

    1990-01-01

    The experience gained over a period of several months, applying the digital and image-enhanced radiography with the DSI system for examination of some hundreds of patients, has confirmed in our eyes the system's diagnostic and economic efficiency, and the important achievement of radiation dose abatement. Looking at the current results and improvements under way (Release 2), there is reason enough to support an extension of the range of indications, especially regarding arteriography and interventional radiography. According to our experience, the DSI system meets the requirements of a modern radiology department: reduction of operating costs, limitation of radiation dose, efficiency enhancement by digital imaging. (orig.) [de

  5. Methodology for digital radiography simulation using the Monte Carlo code MCNPX for industrial applications

    International Nuclear Information System (INIS)

    Souza, E.M.; Correa, S.C.A.; Silva, A.X.; Lopes, R.T.; Oliveira, D.F.

    2008-01-01

    This work presents a methodology for digital radiography simulation for industrial applications using the MCNPX radiography tally. In order to perform the simulation, the energy-dependent response of a BaFBr imaging plate detector was modeled and introduced in the MCNPX radiography tally input. In addition, a post-processing program was used to convert the MCNPX radiography tally output into 16-bit digital images. Simulated and experimental images of a steel pipe containing corrosion alveoli and stress corrosion cracking were compared, and the results showed good agreement between both images

  6. Film-screen digital radiography

    International Nuclear Information System (INIS)

    Schwenker, R.P.; Eger, H.

    1985-01-01

    The excellent performance of the digital film-screen system as a receptor for projection radiographic data is discussed. An experimental system for obtaining high quality digital radiographic data by laser scanning radiographic films is described. This system is being used to evaluate the clinical utility of various digital image processing algorithms. Future plans include an investigation of quantitative analysis of projection radiographic data. Digital data obtained by film scanning can be used with digital image archiving and communications systems. (author)

  7. Axial Tomography from Digitized Real Time Radiography

    Science.gov (United States)

    Zolnay, A. S.; McDonald, W. M.; Doupont, P. A.; McKinney, R. L.; Lee, M. M.

    1985-01-18

    Axial tomography from digitized real time radiographs provides a useful tool for industrial radiography and tomography. The components of this system are: x-ray source, image intensifier, video camera, video line extractor and digitizer, data storage and reconstruction computers. With this system it is possible to view a two dimensional x-ray image in real time at each angle of rotation and select the tomography plane of interest by choosing which video line to digitize. The digitization of a video line requires less than a second making data acquisition relatively short. Further improvements on this system are planned and initial results are reported.

  8. Quality assurance of computed and digital radiography systems

    International Nuclear Information System (INIS)

    Walsh, C.; Gorman, D.; Byrne, P.; Larkin, A.; Dowling, A.; Malone, J. F.

    2008-01-01

    Computed radiography (CR) and digital radiography (DR) are replacing traditional film screen radiography as hospitals move towards digital imaging and picture archiving and communication systems (PACS). Both IPEM and KCARE have recently published quality assurance and acceptance testing guidelines for DR. In this paper, the performance of a range of CR and DR systems is compared. Six different manufacturers are included. Particular attention is paid to the performance of the systems under automatic exposure control (AEC). The patient is simulated using a range of thicknesses of tissue equivalent material. Image quality assessment was based on detector assessment protocols and includes pixel value measures as well as subjective assessment using Leeds Test Objects. The protocols for detector assessment cover a broad range of tests and in general detectors (whether DR or CR) performed satisfactorily. The chief limitation in performing these tests was that not all systems provided ready access to pixel values. Subjective tests include the use of the Leeds TO20. As part of this work, suggested reference values are provided to calculate the TO20 image quality factor. One consequence of moving from film screen to digital technologies is that the dynamic range of digital detectors is much wider, and increased exposures are no longer evident from changes in image quality. As such, AEC is a key parameter for CR and DR. Dose was measured using a standard phantom as a basic means of comparing systems. In order to assess the AEC performance, exit doses were also measured while varying phantom thickness. Signal-to-noise ratios (SNRs) were calculated on a number of systems where pixel values were available. SNR was affected by the selection of acquisition protocol. Comparisons between different technologies and collation of data will help refine acceptance thresholds and contribute to optimising dose and image quality. (authors)

  9. Digital radiography versus conventional radiography during excretory urography: our experience

    International Nuclear Information System (INIS)

    Cervi, P.M.; Bighi, S.; Merlo, L.; Lupi, L.; Vita, G.

    1990-01-01

    The authors describe a computed radiographic system employed to generate and archive digital images in intravenous urography. For each exposure the system produces two digital images: the first (left image) simulates a conventional screen-film radiograph, the second (right image); enhances some spatial frequencies and emphasizes the margins of the structures. These images can be modified in their chief parameters and then printed by a laser-printer and archived on optical disks. Four experienced radiologists evaluated digital images with regard to some chief diagnostic parameters and, in 50 patients, they compared digital images with conventional screen-film radiographs and submitted the results to statistical analysis. For some of the chosen parameters, particularly for the evaluation of renal margins before and after contrast medium injection, digital images gave statistically better results than conventional films, while, no statistically significant different was observed for the other parameters. From the results of this preliminary study digital radiography was found to be useful in intravenous urography by reducing the patient's exposition dose, by always obtaining images of good quality, and by enhancing some particular features of the standard image; on the other hand there were many unsolved problems regarding the communicating and archiving system (PACS), because of the slowness of the image transfer procedure, difficulties in data transmission and complexity of referential procedures

  10. Dysphagia following stroke: evaluation with digital radiography

    International Nuclear Information System (INIS)

    Chu, Sung Nam; Kang, Heoung Keun; Joo, Jung Hyun; Kim, Chang Il; Park, Soo Min; Jeong, Yong Yeon; Seo, Jeong Jin; Chung, Tae Woong

    1997-01-01

    The purpose of this study is to evaluate the usefulness of digital radiography in the assessment of dysphagia following stroke. Eighteen stroke patients (8 men, 10 women) referred for dysphagia and ten controls without known pharyngeal swallowing difficulty underwent digital radiography using a 1:1 mixture of barium and water. We evaluated oropharyngeal transit time and the location and severity of dysphagia; transit time was defined as the time from the first movement of the bolus to the return of the epiglottis to its original position. We sought to observe specific patterns of oropharyngeal dysfunction; dysphagia was classified as mild, moderate, or severe. The dynamic image of the pharynx, as seen on a digital radiograph, may be diagnostically useful for defining the location and severity of dysphagia; in order to make feeding recommendations, this information is essential. (author). 17 refs., 5 figs

  11. Dysphagia following stroke: evaluation with digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Sung Nam; Kang, Heoung Keun; Joo, Jung Hyun; Kim, Chang Il; Park, Soo Min; Jeong, Yong Yeon; Seo, Jeong Jin; Chung, Tae Woong [Chonnam Univ., Kwanju (Korea, Republic of). Medical School

    1997-12-01

    The purpose of this study is to evaluate the usefulness of digital radiography in the assessment of dysphagia following stroke. Eighteen stroke patients (8 men, 10 women) referred for dysphagia and ten controls without known pharyngeal swallowing difficulty underwent digital radiography using a 1:1 mixture of barium and water. We evaluated oropharyngeal transit time and the location and severity of dysphagia; transit time was defined as the time from the first movement of the bolus to the return of the epiglottis to its original position. We sought to observe specific patterns of oropharyngeal dysfunction; dysphagia was classified as mild, moderate, or severe. The dynamic image of the pharynx, as seen on a digital radiograph, may be diagnostically useful for defining the location and severity of dysphagia; in order to make feeding recommendations, this information is essential. (author). 17 refs., 5 figs.

  12. Quality comparison of direct digital panoramic radiography and computed radiography panoramic

    Directory of Open Access Journals (Sweden)

    Dariush Goodarzipour

    2013-09-01

    Full Text Available BACKGROUND AND AIM: Digital panoramic X-ray images can be captured using photostimulable phosphors or solid-state detectors (i.e. charge-coupled devices and Flat-Panels. The first category is defined as computed radiography (CR or semi-direct radiography. The second technology that uses solid-state detectors is known as direct digital radiography (DDR. Both of these technologies have their own advantages and disadvantages. One of the most important fields in comparison of these systems is their resultant image quality. The purpose of this study was to compare the subjective image quality of DDR and CR digital panoramic system, and to assess the overall density and contrast of their images. METHODS: 200 patients were randomly allocated to two digital systems: Promax [central control digital (CCD] and XC [photostimulable phosphor plates (PSP]. Image quality was evaluated in six regions on a 3-point scale by three oral and maxillofacial radiologists independently. In addition, observers assessed overall density and contrast of each image on a 3-point scale. RESULTS: Using chi-square test, no statistically significant differences were found (P >0.05 in subjective image quality of anatomic structures between the two radiographic systems. But DDR system outperformed CR system in overall density and contrast of the image. P values for both overall density and contrast of the images was less than 0.001. CONCLUSIONS: The subjective image quality of CR and DDR panoramic systems in specified anatomic regions were found statistically comparable in this study. In overall density and contrast of the radiographs, DDR system proved better than CR system.

  13. Dual energy radiography using active detector technology

    International Nuclear Information System (INIS)

    Seibert, J.A.; Poage, T.F.; Alvarez, R.E.

    1996-01-01

    A new technology has been implemented using an open-quotes active-detectorclose quotes comprised of two computed radiography (CR) imaging plates in a sandwich geometry for dual-energy radiography. This detector allows excellent energy separation, short exposure time, and high signal to noise ratio (SNR) for clinically robust open-quotes bone-onlyclose quotes and open-quotes soft-tissue onlyclose quotes images with minimum patient motion. Energy separation is achieved by two separate exposures at widely different kVp's: the high energy (120 kVp + 1.5 mm Cu filter) exposure is initiated first, followed by a short burst of intense light to erase the latent image on the front plate, and then a 50 kVp (low energy) exposure. A personal computer interfaced to the x-ray generator, filter wheel, and active detector system orchestrates the acquisition sequence within a time period of 150 msec. The front and back plates are processed using a CR readout algorithm with fixed speed and wide dynamic range. open-quotes Bone-onlyclose quotes and open-quotes soft-tissue onlyclose quotes images are calculated by geometric alignment of the two images and application of dual energy decomposition algorithms on a pixel by pixel basis. Resultant images of a calibration phantom demonstrate an increase of SNR 2 / dose by ∼73 times when compared to a single exposure open-quotes passive-detectorclose quotes comprised of CR imaging plates, and an ∼8 fold increase compared to a screen-film dual-energy cassette comprised of different phosphor compounds. In conclusion, dual energy imaging with open-quotes active detectorclose quotes technology is clinically feasible and can provide substantial improvements over conventional methods for dual-energy radiography

  14. Standard guide for digital detector array radiology

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This standard is a user guide, which is intended to serve as a tutorial for selection and use of various digital detector array systems nominally composed of the detector array and an imaging system to perform digital radiography. This guide also serves as an in-detail reference for the following standards: Practices E2597, , and E2737. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  15. Digital radiography for quality assurance

    International Nuclear Information System (INIS)

    Thiele, H.; Friemel, H.J.

    2001-01-01

    The digital radiographic system AMICA-401 is described. It is a mobile system originally developed for wall thickness and diameter measurements of insulated and non-insulated pipes which is also suited for quality assurance in fabrication and maintenance. Its advantages are immediate evaluation of images, very short exposure times with reduced radiation loads, and an efficient integrated image processing software. Further, no chemical substances are required for film processing. The system can be used both in mobile and in stationary applications. Practical examples are presented and discussed. (orig.) [de

  16. Clinical application of digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Hiroyuki; Nagasaka, Hideo; Himi, Kazuhisa [Nihon Univ., Tokyo. School of Medicine

    1983-04-01

    Utility of digital subtraction angiography (DSA) by fluorography was advocated with demonstrable clinical cases. DSA is drawing attention for use at the outpatient clinic because it is relatively noninvasive, involves less risk than that by catheterization, and can be performed by intravenous injection. It also has a number of advantages such as instantaneous imaging and possible imaging of multiple sites by the same procedure. It still be extensively used in clinical practice not only as a screening method, but also as a functional imaging one.

  17. Image processing in digital chest radiography

    International Nuclear Information System (INIS)

    Manninen, H.; Partanen, K.; Lehtovirta, J.; Matsi, P.; Soimakallio, S.

    1992-01-01

    The usefulness of digital image processing of chest radiographs was evaluated in a clinical study. In 54 patients, chest radiographs in the posteroanterior projection were obtained by both 14 inch digital image intensifier equipment and the conventional screen-film technique. The digital radiographs (512x512 image format) viewed on a 625 line monitor were processed in 3 different ways: 1.standard display; 2.digital edge enhancement for the standard display; 3.inverse intensity display. The radiographs were interpreted independently by 3 radiologists. Diagnoses were confirmed by CT, follow-up radiographs and clinical records. Chest abnormalities of the films analyzed included 21 primary lung tumors, 44 pulmonary nodules, 16 cases with mediastinal disease, 17 with pneumonia /atelectasis. Interstitial lung disease, pleural plaques, and pulmonary emphysema were found in 30, 18 and 19 cases respectively. Sensitivity of conventional radiography when averaged overall findings was better than that of digital techniques (P<0.001). Differences in diagnostic accuracy measured by sensitivity and specificity between the 3 digital display modes were small. Standard image display showed better sensitivity for pulmonary nodules (0.74 vs 0.66; P<0.05) but poorer specificity for pulmonary emphysema (0.85 vs 0.93; P<0.05) compared with inverse intensity display. It is concluded that when using 512x512 image format, the routine use of digital edge enhancement and tone reversal at digital chest radiographs is not warranted. (author). 12 refs.; 4 figs.; 2 tabs

  18. Digital radiography: a quantitative approach

    International Nuclear Information System (INIS)

    Retraint, F.

    2004-01-01

    'Full-text:' In a radiograph the value of each pixel is related to the material thickness crossed by the x-rays. Using this relationship, an object can be characterized by parameters such as depth, surface and volume. Assuming a locally linear detector response and using a radiograph of reference object, the quantitative thickness map of object can be obtained by applying offset and gain corrections. However, for an acquisition system composed of cooled CCD camera optically coupled to a scintillator screen, the radiographic image formation process generates some bias which prevent from obtaining the quantitative information: non uniformity of the x-ray source, beam hardening, Compton scattering, scintillator screen, optical system response. In a first section, we propose a complete model of the radiographic image formation process taking account of these biases. In a second section, we present an inversion scheme of this model for a single material object, which enables to obtain the thickness map of the object crossed by the x-rays. (author)

  19. Digital radiography: description and user's guide

    Energy Technology Data Exchange (ETDEWEB)

    Berthel, A. [Cryospace, 78 - Les Mureaux (France); Bonin, Th. [CEA Valduc, 21 - Is-sur-Tille (France); Cadilhon, S.; Thiery, Ch. [CEA Bruyeres-le-Chatel, 91 (France); Chatellier, L. [Electricite de France (EDF-RD), Recherche et Developpement, 78 - Chatou (France); Kaftandjian, V. [Lyon Univ., INSA Lab. Controle Non Destructif par Rayonnements Ionisants (CNDRI), 69 (France); Honorat, Ph.; Torrent, J. [SNECMA, 75 - Paris (France); Le Brun, A. [Electricite de France, 78 - Chatou (France); Maglaive, J.C. [Euromev, 78 - Buc (France); Moreau, Ph. [General Electric Industrial Inspection Technologies, 69 - Limonest (France); Pettier, J.L. [CEA Cadarach, Dir. de l' Energie Nucleaire, 13 - Saint Paul lez Durance (France); Rebuffel, V. [CEA Grenoble, Lab. d' Electronique et de Technologie de l' Informatique (LETI), 38 (France); Roenelle, P. [Centre d' Etudes Techniques de l' Equipement, 69 - Bron Lyon (France); Roussilhe, J. [Carestream Health France SA, 71 - Chalon/Saone (France); Staat, St.; Tahon, M. [Cegelec, 91 - Bretigny sur Orge (France)

    2007-07-01

    The presented document arises from the work of the group 'Digital Radiography and sensors' of COFREND. It is a collective work of synthesis aimed to analyze the quality parameters of digital images influencing the answer and the diagnosis brought to a given industrial problem. Five families of digital sensors have been studied: 1. Image Intensifier coupled with CCD devices - 2. scintillators coupled with a CCD device- 3. Flat Panels with indirect conversion - 4. Flat Panels with direct electric conversion - 5. Photostimulable Storage Phosphor Screens). In particular, concerning a complete imaging chain, it deals with the notions of magnification, blur (unsharpness) (geometrical, kinetic or internal to the very sensor), noises, scattered radiation, spatial resolution, which is different from the one of analog detectors such as films, Contrast to Noise Ratio (CNR), sensitivity using IQIs, dynamic range, detection quantum efficiency, persistence and temporal resolution. This document is not a standard; it must be understood as a user's guide, and it approaches some essentials corrections to bring to a sensor in order to optimize his efficiency without losing information during the pre-processing phase in the radiographic acquisition. It also introduces some image processing tools commonly used. It can be used as a source document to the future elaboration of a standardisation document. It augurs not at all of the choice of a digital sensor with regard to the traditional radiographic film, but gives bases of reflection to a radio user for a sensible transfer from the classic radiography to the digital radiography. (authors)

  20. Image rejects in general direct digital radiography

    International Nuclear Information System (INIS)

    Hofmann, Bjørn; Rosanowsky, Tine Blomberg; Jensen, Camilla; Wah, Kenneth Hong Ching

    2015-01-01

    The number of rejected images is an indicator of image quality and unnecessary imaging at a radiology department. Image reject analysis was frequent in the film era, but comparably few and small studies have been published after converting to digital radiography. One reason may be a belief that rejects have been eliminated with digitalization. To measure the extension of deleted images in direct digital radiography (DR), in order to assess the rates of rejects and unnecessary imaging and to analyze reasons for deletions, in order to improve the radiological services. All exposed images at two direct digital laboratories at a hospital in Norway were reviewed in January 2014. Type of examination, number of exposed images, and number of deleted images were registered. Each deleted image was analyzed separately and the reason for deleting the image was recorded. Out of 5417 exposed images, 596 were deleted, giving a deletion rate of 11%. A total of 51.3% were deleted due to positioning errors and 31.0% due to error in centering. The examinations with the highest percentage of deleted images were the knee, hip, and ankle, 20.6%, 18.5%, and 13.8% respectively. The reject rate is at least as high as the deletion rate and is comparable with previous film-based imaging systems. The reasons for rejection are quite different in digital systems. This falsifies the hypothesis that digitalization would eliminates rejects. A deleted image does not contribute to diagnostics, and therefore is an unnecessary image. Hence, the high rates of deleted images have implications for management, training, education, as well as for quality

  1. Noise analysis of a digital radiography system

    International Nuclear Information System (INIS)

    Arnold, B.A.; Scheibe, P.O.

    1984-01-01

    The sources of noise in a digital video subtraction angiography system were identified and analyzed. Signal-to-noise ratios of digital radiography systems were measured using the digital image data recorded in the computer. The major sources of noise include quantum noise, TV camera electronic noise, quantization noise from the analog-to-digital converter, time jitter, structure noise in the image intensifier, and video recorder electronic noise. A new noise source was identified, which results from the interplay of fixed pattern noise and the lack of image registration. This type of noise may result from image-intensifier structure noise in combination with TV camera time jitter or recorder time jitter. A similar noise source is generated from the interplay of patient absorption inhomogeneities and patient motion or image re-registration. Signal-to-noise ratios were measured for a variety of experimental conditions using subtracted digital images. Image-intensifier structure noise was shown to be a dominant noise source in unsubtracted images at medium to high radiation exposure levels. A total-system signal-to-noise ratio (SNR) of 750:1 was measured for an input exposure of 1 mR/frame at the image intensifier input. The effect of scattered radiation on subtracted image SNR was found to be greater than previously reported. The detail SNR was found to vary approximately as one plus the scatter degradation factor. Quantization error noise with 8-bit image processors (signal-to-noise ratio of 890:1) was shown to be of increased importance after recent improvements in TV cameras. The results of the analysis are useful both in the design of future digital radiography systems and the selection of optimum clinical techniques

  2. Image rejects in general direct digital radiography.

    Science.gov (United States)

    Hofmann, Bjørn; Rosanowsky, Tine Blomberg; Jensen, Camilla; Wah, Kenneth Hong Ching

    2015-10-01

    The number of rejected images is an indicator of image quality and unnecessary imaging at a radiology department. Image reject analysis was frequent in the film era, but comparably few and small studies have been published after converting to digital radiography. One reason may be a belief that rejects have been eliminated with digitalization. To measure the extension of deleted images in direct digital radiography (DR), in order to assess the rates of rejects and unnecessary imaging and to analyze reasons for deletions, in order to improve the radiological services. All exposed images at two direct digital laboratories at a hospital in Norway were reviewed in January 2014. Type of examination, number of exposed images, and number of deleted images were registered. Each deleted image was analyzed separately and the reason for deleting the image was recorded. Out of 5417 exposed images, 596 were deleted, giving a deletion rate of 11%. A total of 51.3% were deleted due to positioning errors and 31.0% due to error in centering. The examinations with the highest percentage of deleted images were the knee, hip, and ankle, 20.6%, 18.5%, and 13.8% respectively. The reject rate is at least as high as the deletion rate and is comparable with previous film-based imaging systems. The reasons for rejection are quite different in digital systems. This falsifies the hypothesis that digitalization would eliminates rejects. A deleted image does not contribute to diagnostics, and therefore is an unnecessary image. Hence, the high rates of deleted images have implications for management, training, education, as well as for quality.

  3. Digital chest radiography system with amorphous selenium flat-panel detectors: qualitative and dosimetric comparison with a dedicated film-screen system

    International Nuclear Information System (INIS)

    Prato, Antonio; Fava Cesare; Ropolo, Roberto

    2005-01-01

    Purpose. To compare the quality and radiation dose of a conventional film-screen system and a digital system with amorphous selenium detectors in the study of the chest, by verifying overall performance and exposure levels for the main chest structures in patients of different sizes. Materials and methods. An analogic system (Chest Changer, Dupont, Day-light model 1000) and a digital system (Directray Rad 1000C, Hologic) were tested on a total of 1000 patients randomly assigned to one of two groups of 500 subjects.The patients were further subdivided according to BMI (Body Mass Index). Image quality was determined by two chest radiologists who evaluated eight anatomical structures. The entrance surface dose (skin-dose), calculated based on the exposure parameters, was taken as the patient dose. Results. Mean dose delivered was very similar for both techniques in the PA view (0.28 mGy), but it was greater in the LL projections obtained with the digital system (1.20 rnGy versus 0.83 mGy). The highest overall scores were assigned to 43% and 23.2% analogic radiograms and 64% and 70.2% digital radiograms, for the PA and LL projections respectively. The scores assigned to the various anatomical structures confirmed the better performance of the digital system in almost all of the regions considered. Conclusions. The mean quality of radiograms is definitely higher with the digital system, in particular in the LL projections, where the higher patient doses are counterbalanced by fewer repeated scans. The greater level of exposure in the digital system appears nonetheless tolerable on account of the greater informativeness and therefore diagnostic gain and also considering the possibilities for improving the system [it

  4. Practical evaluation of clinical image quality (4). Determination of image quality in digital radiography system

    International Nuclear Information System (INIS)

    Katayama, Reiji

    2016-01-01

    Recently, for medical imaging, digital radiography systems are widely used in clinical practices. However, a study in the past reported that a patient radiation exposure level by digital radiography is in fact not lower than that by analog radiography system. High level of attention needs to be paid for over-exposure when using the conventional analog radiography with a screen and a film, as it results in high density of the film. However, for digital radiography systems, since the automatic adjusting function of image density is equipped with them, no attention for radiation dose need to be paid. Thus technologists tend to be careless and results in higher chance for over-exposure. Current digital radiography systems are high-performance in the image properties and capable of patient dose reduction. Especially, the image quality of the flat panel detector system is recognized, higher than that of the computed radiography system by imaging plates, in both objective and subjective evaluations. Therefore, we technologists are responsible for optimizing the balance between the image quality of the digital radiogram and the radiation dose required for each case. Moreover, it is also required for us as medical technologists to make effective use of such evaluation result of medical images for patients. (author)

  5. Digital Radiography Qualification of Tube Welding

    Science.gov (United States)

    Carl, Chad

    2012-01-01

    The Orion Project will be directing Lockheed Martin to perform orbital arc welding on commodities metallic tubing as part of the Multi Purpose Crew Vehicle assembly and integration process in the Operations and Checkout High bay at Kennedy Space Center. The current method of nondestructive evaluation is utilizing traditional film based x-rays. Due to the high number of welds that are necessary to join the commodities tubing (approx 470), a more efficient and expeditious method of nondestructive evaluation is desired. Digital radiography will be qualified as part of a broader NNWG project scope.

  6. A method of detector correction for cosmic ray muon radiography

    International Nuclear Information System (INIS)

    Liu Yuanyuan; Zhao Ziran; Chen Zhiqiang; Zhang Li; Wang Zhentian

    2008-01-01

    Cosmic ray muon radiography which has good penetrability and sensitivity to high-Z materials is an effective way for detecting shielded nuclear materials. The problem of data correction is one of the key points of muon radiography technique. Because of the influence of environmental background, environmental yawp and error of detectors, the raw data can not be used directly. If we used the raw data as the usable data to reconstruct without any corrections, it would turn up terrible artifacts. Based on the characteristics of the muon radiography system, aimed at the error of detectors, this paper proposes a method of detector correction. The simulation experiments demonstrate that this method can effectively correct the error produced by detectors. Therefore, we can say that it does a further step to let the technique of cosmic muon radiography into out real life. (authors)

  7. Bacteriological research for the contamination of digital portable radiography

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Seong Gyu [Dept. of Radiology, Dong A University Hospital, Busan (Korea, Republic of); Lee, Hyo Yeong [Dept. of Radiological Science, Dong Eui University, Busan (Korea, Republic of)

    2017-03-15

    The study was performed to investigate the bacteriological contamination of portable digital radiography system and their detectors in a university hospital. CNS and VRE were detected in the samples collected from vinyl cover on detectors used for the infection control patients. On the other hand, no bacteria was detected in the samples collected from detectors with vinyl cover removed. In the series of imaging of patients from general wards, no bacteria was detected from the patient 1. However, CNS was detected from the patients 2 and 3, CNS and Enterococcus faecalis detected from the patient 4, CNS and Enterococcus casseliflavus detected from the patient 5, and CNS, Enterococcus casseliflavus, and Klebsiella pneumoniae all detected from the patient 6. CNS and Enterococcus faecium were detected in the controller handle of collimator. Also, CNS was detected from the handle of detector and exposure switch. In the treatment gloves of the radiological technologist after the imaging, CNS, Enterococcus gallinarum, and Klebsiella pneumoniae were detected. Therefore, it is recommended for DR portable to take images after sterilizing the detector after taking each image and to use disposable vinyl covers on detectors to remove after imaging. And treatment gloves must be changed after each imaging. Also, hospital infection via portables must be prevented by complete sterilization of the controller handles of collimator which are in frequent contact during imaging and infection education of employees.

  8. Computer processing techniques in digital radiography research

    International Nuclear Information System (INIS)

    Pickens, D.R.; Kugel, J.A.; Waddill, W.B.; Smith, G.D.; Martin, V.N.; Price, R.R.; James, A.E. Jr.

    1985-01-01

    In the Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, and the Center for Medical Imaging Research, Nashville, TN, there are several activities which are designed to increase the information available from film-screen acquisition as well as from direct digital acquisition of radiographic information. Two of the projects involve altering the display of images after acquisition, either to remove artifacts present as a result of the acquisition process or to change the manner in which the image is displayed to improve the perception of details in the image. These two projects use methods which can be applied to any type of digital image, but are being implemented with images digitized from conventional x-ray film. One of these research endeavors involves mathematical alteration of the image to correct for motion artifacts or registration errors between images that will be subtracted. Another applies well-known image processing methods to digital radiographic images to improve the image contrast and enhance subtle details in the image. A third project involves the use of dual energy imaging with a digital radiography system to reconstruct images which demonstrate either soft tissue details or the osseous structures. These projects are discussed in greater detail in the following sections of this communication

  9. The advantages of digital radiography in department of radiology

    International Nuclear Information System (INIS)

    Mao Lijuan; Luo Xiaomei; Wu Tengfang

    2009-01-01

    Objective: To investigate the advantages of digital radiography in department of radiology by comparing digital radiography with common radiography. Methods: Test card was used for testing the spatial resolution of DR and common radiography. 1000 films of chest by DR and 1000 films of chest by common radiography were compared in image quality, dose of radiation, the rate of waste film, and the advantages of DR was analyzed. Results: Compared to common radiography, DR had a high sensitivity, high DQE (quantum detection efficiency), high spatial resolution and density resolution. The speed of acquisition and X-ray conversion efficiency were fast. The function of post-processing was strong and the rate of disease detection was high. Conclusion: DR is better than common radiography in all respects, it will be widely applied. (authors)

  10. Direct detector radiography versus dual reading computed radiography: feasibility of dose reduction in chest radiography

    International Nuclear Information System (INIS)

    Gruber, Michael; Uffmann, Martin; Weber, Michael; Balassy, Csilla; Schaefer-Prokop, Cornelia; Prokop, Mathias

    2006-01-01

    The image quality of dual-reading computed radiography and dose-reduced direct radiography of the chest was compared in a clinical setting. The study group consisted of 50 patients that underwent three posteroanterior chest radiographs within minutes, one image obtained with a dual read-out computed radiography system (CR; Fuji 5501) at regular dose and two images with a flat panel direct detector unit (DR; Diagnost, Philips). The DR images were obtained with the same and with 50% of the dose used for the CR images. Images were evaluated in a blinded side-by-side comparison. Eight radiologists ranked the visually perceivable difference in image quality using a three-point scale. Then, three radiologists scored the visibility of anatomic landmarks in low and high attenuation areas and image noise. Statistical analysis was based on Friedman tests and Wilcoxon rank sum tests at a significance level of P<0.05. DR was judged superior to CR for the delineation of structures in high attenuation areas of the mediastinum even when obtained with 50% less dose (P<0.001). The visibility of most pulmonary structures was judged equivalent with both techniques, regardless of acquisition dose and speed level. Scores for image noise were lower for DR compared with CR, with the exception of DR obtained at a reduced dose. Thus, in this clinical preference study, DR was equivalent or even superior to the most modern dual read-out CR, even when obtained with 50% dose. A further dose reduction does not appear to be feasible for DR without significant loss of image quality. (orig.)

  11. A review of digital radiography technology for valve inspection

    International Nuclear Information System (INIS)

    Stoev, K.; Guerout, F.M.; Horn, D.

    2008-01-01

    There are thousands of valves in a nuclear power plant (NPP) used for control, safety and checks in various plant systems, so there is a well-identified need for fast and reliable inspection and diagnostics of valves. Digital radiography can provide considerable improvements to the inspection and testing procedures for valves in comparison to classical film radiography. These improvements can lead to significant financial advantages by providing real-time inspection results, significantly reduced inspection and decision-making time, and reduced operational cost. Digital image processing, including digital image enhancement, digital archiving, and digital communication of the images and the results, is also a considerable advantage over classical film radiography technology. Another advantage of digital radiography technology is the improved safety and the reduced environmental impact due to reduced exposure/test times, use of smaller exclusion zones, elimination of chemical processing, and absence of disposable materials. This paper reviews the existing technology and evaluates the potential of digital radiography for inspection and diagnostics of valves. Station needs and requirements are assessed, and the safety, environmental and economical constraints of digital radiography techniques estimated. The advantages and disadvantages of different digital radiography equipment are compared, and their limitations and characteristics studied. (author)

  12. Digital projection radiography. Technical principles, image properties and potential applications

    International Nuclear Information System (INIS)

    Busch, H.P.

    1999-01-01

    The history of development of digital projection radiography as a diagnostic method is presented in a comprehensive survey. The various technical principles are explained in detail and illustrated by means of graphic figures and digital X-ray pictures. A comparative assessment of currently applied radiographic systems is given and the potential clinical applications of the method of digital projection radiography are discussed. (orig./CB) [de

  13. Evaluation of the effectiveness of digital radiography in emergency situations

    International Nuclear Information System (INIS)

    Pathi, R.; Langlois, S.

    2002-01-01

    The time differences between digital and conventional radiography for emergency patients were investigated, and clinician satisfaction with the two modalities was compared. Time-motion data was collected daily over 5 weeks for a digital group and a conventional X-ray group. For standardization purposes, only emergency patients requiring chest X-rays were selected for the study. Data were collected from 30 patients in each of the two groups in the time-motion study, and 31 out of 50 Emergency and Intensive Care clinicians responded to the questionnaire. Results were analysed by percentage, and χ 2 analysis was used where appropriate. The time for availability of images to requesting clinicians was 70% less for digital images compared to conventional radiography. The overall satisfaction between digital and conventional radiography was very similar, but most clinicians expressed an opinion that digital radiography offered significant image modification advantages. Copyright (2002) Blackwell Science Pty Ltd

  14. Digital Radiography of a Drop Tested 9975 Radioactive Materials Packaging

    International Nuclear Information System (INIS)

    Blanton, P.S.

    2001-01-01

    This paper discusses the use of radiography as a tool for evaluating damage to radioactive material packaging subjected to regulatory accident conditions. The Code of Federal Regulations, 10 CFR 71, presents the performance based requirements that must be used in the development (design, fabrication and testing) of a radioactive material packaging. The use of various non-destructive examination techniques in the fabrication of packages is common. One such technique is the use of conventional radiography in the examination of welds. Radiography is conventional in the sense that images are caught one at a time on film stock. Most recently, digital radiography has been used to characterize internal damage to a package subjected to the 30-foot hypothetical accident conditions (HAC) drop. Digital radiography allows for real time evaluation of the item being inspected. This paper presents a summary discussion of the digital radiographic technique and an example of radiographic results of a 9975 package following the HAC 30-foot drop

  15. Developments in digital radiography: an equipment update

    International Nuclear Information System (INIS)

    James, J.J.; O'Connor, P.J.; Davies, A.G.; Cowen, A.R.

    2001-01-01

    Digital X-ray imaging technology has advanced rapidly over the past few years. This review, particularly aimed at those involved in using and purchasing such technology, is an attempt to unravel some of the complexities of this potentially confusing subject. The main groups of X-ray imaging devices that are considered are digitisers of conventional radiographs, image-intensifier-based fluorography systems, photostimulable phosphor computed radiography, amorphous selenium-based technology for thorax imaging and flat-panel systems. As well as describing these different systems, we look at ways of objectively assessing their image quality. Concepts that are used and explained include spatial resolution, grey-scale bit resolution, signal-to-noise ratio and detective quantum efficiency. An understanding of these basic parameters is vital in making a scientific assessment of a system's performance. Image processing and techniques are also briefly discussed, particularly with reference to their potential effects on image quality. This review aims to provide a basic understanding of digital X-ray imaging technology and enables the reader to make an independent and educated assessment of the relative merits of each system. (orig.)

  16. Image quality and dose management in digital radiography: A new paradigm for optimisation

    International Nuclear Information System (INIS)

    Busch, H. P.; Faulkner, K.

    2005-01-01

    The advent of digital imaging in radiology, combined with the explosive growth of technology, has dramatically improved imaging techniques. This has led to the expansion of diagnostic capabilities, both in terms of the number of procedures and their scope. Throughout the world, film/ screen radiography systems are being rapidly replaced with digital systems. Many progressive medical institutions have acquired, or are considering the purchase of computed radiography systems with storage phosphor plates or direct digital radiography systems with flat panel detectors. However, unknown to some users, these devices offer a new paradigm of opportunity and challenges. Images can be obtained at a lower dose owing to the higher detective quantum efficiency (DQE). These fundamental differences in comparison to conventional film/screens necessitate the development of new strategies for dose and quality optimisations. A set of referral criteria based upon three dose levels is proposed. (authors)

  17. Evaluation of a new type of direct digital radiography machine ...

    African Journals Online (AJOL)

    Evaluation of a new type of direct digital radiography machine. ... Ease of use, anatomical coverage and tolerance to patient motion were advantages. ... to that of conventional radiographs, with limited fine detail visibility and penetration.

  18. Principles and applications of the digital luminescent radiography

    International Nuclear Information System (INIS)

    Doehring, W.; Prokop, M.; Bergh, B.

    1986-01-01

    Digital luminescent radiography is a novel technique for routine diagnostics that allows the establishment of digital projection radiograms. Two goals are pursued: Best possible utilisation of the image data contained in the radiation field, and integration of these data into a digital communication system. (orig.) [de

  19. Inspection reliability comparison of digital radiography, film radiography and radioscopy for inspection of Inconel welds

    International Nuclear Information System (INIS)

    Meade, W.; Kidwell, C.; Warren, G.

    2004-01-01

    Digital Radiography offers the promise of economic and environmental advantages over traditional film based inspection. Boeing Commercial Aircraft Group has an on-going effort to evaluate this emerging radiographic method for production of aerospace hardware. Included in this effort was a program to evaluate the potential for utilizing amorphous silicon based digital radiography for the inspection of inconel weldments in engine ducting. For this particular program, probability of detection (POD) studies were conducted to compare the reliability of digital radiography with the existing production processes that utilize film radiography and image-intensifier based radioscopy. Cycle time studies were also conducted to determine the potential economic benefit for switching to the new process. The methodology and findings of this comparison are presented. (author)

  20. Inspection reliability comparison of digital radiography, film radiography and radioscopy for inspection of Inconel welds

    Energy Technology Data Exchange (ETDEWEB)

    Meade, W.; Kidwell, C.; Warren, G. [Boeing Commercial Aircraft Group, Renton, Washington (United States)

    2004-07-01

    Digital Radiography offers the promise of economic and environmental advantages over traditional film based inspection. Boeing Commercial Aircraft Group has an on-going effort to evaluate this emerging radiographic method for production of aerospace hardware. Included in this effort was a program to evaluate the potential for utilizing amorphous silicon based digital radiography for the inspection of inconel weldments in engine ducting. For this particular program, probability of detection (POD) studies were conducted to compare the reliability of digital radiography with the existing production processes that utilize film radiography and image-intensifier based radioscopy. Cycle time studies were also conducted to determine the potential economic benefit for switching to the new process. The methodology and findings of this comparison are presented. (author)

  1. Comparison of the efficacy of conventional radiography, digital radiography, and ultrasound in diagnosing periapical lesions.

    Science.gov (United States)

    Raghav, Namita; Reddy, Sujatha S; Giridhar, A G; Murthy, Srinivas; Yashodha Devi, B K; Santana, N; Rakesh, N; Kaushik, Atul

    2010-09-01

    The aim of this study was to evaluate the efficacy of conventional radiography, digital radiography and ultrasound imaging in diagnosing periapical lesions. Twenty-one patients aged between 15 and 45 years with well defined periapical radiolucency associated with anterior maxillary or mandibular teeth requiring endodontic surgery or extraction were selected and consented to the study. Preoperative intraoral periapical radiographs and digital images using charge-coupled device obtained by paralleling technique were assessed by 3 specialist observers who gave their diagnosis of the periapical lesions. Then ultrasound examination was performed and the images were assessed for size, contents, and vascular supply by 3 ultrasonographers. It was followed by curettage of periapical tissues to enable histopathologic investigation, which is the gold standard in diagnosis. The data were statistically analyzed using SPSS, analysis of variance, and kappa statistics. The percentage accuracy of diagnosing periapical lesions using conventional radiography was 47.6%, digital radiography 55.6%, and ultrasound 95.2%. Ultrasound had the highest sensitivity and specificity: 0.95 and 1.00, respectively. Conventional and digital radiography enable diagnosis of periapical diseases, but not their nature, whereas ultrasound provides accurate information on the pathologic nature of the lesions, which is of importance in predicting the treatment outcome. Therefore ultrasound can be used as an adjunct to conventional or digital radiography in diagnosing periapical lesions. Copyright (c) 2010 Mosby, Inc. All rights reserved.

  2. Comparison of the quality of the chest film between digital radiography and conventional high kV radiography

    International Nuclear Information System (INIS)

    Zeng Qingsi; Cen Renli; Chen Ling; He Jianxun; Lin Hanfei

    2003-01-01

    Objective: To evaluate the quality and usefulness of direct digital radiography system in roentgenogram of chest in clinical practice. Methods: 1000 cases of chest roentgenograms with digital radiography and high kV conventional radiography were selected for analysis by 3 senior radiologists. Results: 1. With digital radiography system, the quality of chest film was assessed as grade A in 50.6%, grade B in 38.5%, grade C in 10.9%, and no waste film. 2. With conventional high kV radiography, the quality of chest film was assessed as grade A in 41.1%, grade B in 44.1%, grade C in 13.3%, and waste film in 1.5%. The direct digital radiography was statistically superior to the conventional high kV radiography. 3. The fine structure of the lungs could be revealed in 100.0% of chest roentgenogram with direct digital radiograph system, which was significantly higher than that acquired with the conventional high KV radiography (78.6%, P < 0.001). Conclusion: Direct digital radiography could provide the chest film with better quality than that with the conventional high kV radiography. The direct digital radiography system is easy to operate, fast in capturing imaging and could provide post-processing techniques, which will facilitate the accurate diagnosis of chest radiography

  3. The MU-RAY detector for muon radiography of volcanoes

    Energy Technology Data Exchange (ETDEWEB)

    Anastasio, A. [INFN-Napoli (Italy); Ambrosino, F. [INFN-Napoli (Italy); Università Federico II, Napoli (Italy); Basta, D. [INFN-Napoli (Italy); Bonechi, L. [Università degli Studi di Firenze, Firenze (Italy); INFN-Firenze (Italy); Brianzi, M. [Università degli Studi di Firenze, Firenze (Italy); Bross, A. [Fermilab (United States); Callier, S. [LAL, Orsay (France); Caputo, A. [INGV Osservatorio Vesuviano, Napoli (Italy); Ciaranfi, R. [INFN-Firenze (Italy); Cimmino, L. [INFN-Napoli (Italy); Università Federico II, Napoli (Italy); D' Alessandro, R. [Università degli Studi di Firenze, Firenze (Italy); INFN-Firenze (Italy); D' Auria, L. [INGV Osservatorio Vesuviano, Napoli (Italy); La Taille, C. de [LAL, Orsay (France); Energico, S. [CNR- SPIN, Napoli (Italy); INFN-Napoli (Italy); Garufi, F. [INFN-Napoli (Italy); Università Federico II, Napoli (Italy); Giudicepietro, F. [INGV Osservatorio Vesuviano, Napoli (Italy); Lauria, A. [INFN-Napoli (Italy); Università Federico II, Napoli (Italy); Macedonio, G.; Martini, M. [INGV Osservatorio Vesuviano, Napoli (Italy); Masone, V. [Università Federico II, Napoli (Italy); and others

    2013-12-21

    The MU-RAY detector has been designed to perform muon radiography of volcanoes. The possible use on the field introduces several constraints. First the electric power consumption must be reduced to the minimum, so that the detector can be solar-powered. Moreover it must be robust and transportable, for what concerns the front-end electronics and data acquisition. A 1 m{sup 2} prototype has been constructed and is taking data at Mt. Vesuvius. The detector consists of modules of 32 scintillator bars with wave length shifting fibers and silicon photomultiplier read-out. A dedicated front-end electronics has been developed, based on the SPIROC ASIC. An introduction to muon radiography principles, the MU-RAY detector description and results obtained in laboratory will be presented.

  4. Dynamic chest radiography: flat-panel detector (FPD) based functional X-ray imaging.

    Science.gov (United States)

    Tanaka, Rie

    2016-07-01

    Dynamic chest radiography is a flat-panel detector (FPD)-based functional X-ray imaging, which is performed as an additional examination in chest radiography. The large field of view (FOV) of FPDs permits real-time observation of the entire lungs and simultaneous right-and-left evaluation of diaphragm kinetics. Most importantly, dynamic chest radiography provides pulmonary ventilation and circulation findings as slight changes in pixel value even without the use of contrast media; the interpretation is challenging and crucial for a better understanding of pulmonary function. The basic concept was proposed in the 1980s; however, it was not realized until the 2010s because of technical limitations. Dynamic FPDs and advanced digital image processing played a key role for clinical application of dynamic chest radiography. Pulmonary ventilation and circulation can be quantified and visualized for the diagnosis of pulmonary diseases. Dynamic chest radiography can be deployed as a simple and rapid means of functional imaging in both routine and emergency medicine. Here, we focus on the evaluation of pulmonary ventilation and circulation. This review article describes the basic mechanism of imaging findings according to pulmonary/circulation physiology, followed by imaging procedures, analysis method, and diagnostic performance of dynamic chest radiography.

  5. Development of ''SonialvisionSafireII'' system with a new digital radiography device

    International Nuclear Information System (INIS)

    Sano, Takayuki; Okumura, Takeshi; Sakai, Takihito; Fujiwara, Masashi; Toyoda, Toshihide

    2007-01-01

    We released the world's first X-TV system equipped with a 17 inch direct conversion type flat panel X-ray detector (FPD) ''Safire'' in an radiofrequency (RF) table in 2004. Our latest X-TV system, called SonialvisionSafireII, incorporates the digital radiography device and the high voltage generator both of which were newly developed to take better advantage of the characteristics of the FPD. The following are the features of the latest system: Image acquisition and processing with the original matrix of FPD (up to 2880 x 2880 matrix with a 17-inch field of view (FOV)), High-speed radiography in serial acquisition mode (up to 15 fps) and tomosynthesis acquisition mode (up to 30 fps), Operationally improved digital radiography device using a general-purpose personal computer. (author)

  6. Quantitative digital radiography with two dimensional flat panels

    International Nuclear Information System (INIS)

    Dinten, J.M.; Robert-Coutant, C.; Darboux, M.

    2003-01-01

    Purpose: Attenuation law relates radiographic images to irradiated object thickness and chemical composition. Film radiography exploits qualitatively this property for diagnosis. Digital radiographic flat panels present large dynamic range, reproducibility and linearity properties which open the gate for quantification. We will present, through two applications (mammography and bone densitometry), an approach to extract quantitative information from digital 2D radiographs. Material and method: The main difficulty for quantification is X-rays scatter, which superimposes to acquisition data. Because of multiple scatterings and 3D geometry dependence, it cannot be directly exploited through an exact analytical model. Therefore we have developed an approach for its estimation and subtraction from medical radiographs, based on approximations and derivations of analytical models of scatter formation in human tissues. Results: In digital mammography, the objective is to build a map of the glandular tissue thickness. Its separation from fat tissue is based on two equations: height of compression and attenuation. This last equation needs X-Rays scatter correction. In bone densitometry, physicians look for quantitative bone mineral density. Today, clinical DEXA systems use collimated single or linear detectors to eliminate scatter. This scanning technology induces poor image quality. By applying our scatter correction approach, we have developed a bone densitometer using a digital flat panel (Lexxos, DMS). It provides with accurate and reproducible measurements while presenting radiological image quality. Conclusion: These applications show how information processing, and especially X-Rays scatter processing, enables to extract quantitative information from digital radiographs. This approach, associated to Computer Aided Diagnosis algorithms or reconstructions algorithms, gives access to useful information for diagnosis. (author)

  7. Temporal digital subtraction radiography with a personal computer digital workstation

    International Nuclear Information System (INIS)

    Kircos, L.; Holt, W.; Khademi, J.

    1990-01-01

    Technique have been developed and implemented on a personal computer (PC)-based digital workstation to accomplish temporal digital subtraction radiography (TDSR). TDSR is useful in recording radiologic change over time. Thus, this technique is useful not only for monitoring chronic disease processes but also for monitoring the temporal course of interventional therapies. A PC-based digital workstation was developed on a PC386 platform with add-in hardware and software. Image acquisition, storage, and processing was accomplished using 512 x 512 x 8- or 12-bit frame grabber. Software and hardware were developed to accomplish image orientation, registration, gray scale compensation, subtraction, and enhancement. Temporal radiographs of the jaws were made in a fixed and reproducible orientation between the x-ray source and image receptor enabling TDSR. Temporal changes secondary to chronic periodontal disease, osseointegration of endosseous implants, and wound healing were demonstrated. Use of TDSR for chest imaging was also demonstrated with identification of small, subtle focal masses that were not apparent with routine viewing. The large amount of radiologic information in images of the jaws and chest may obfuscate subtle changes that TDSR seems to identify. TDSR appears to be useful as a tool to record temporal and subtle changes in radiologic images

  8. A comparison of digital mammography detectors and emerging technology

    International Nuclear Information System (INIS)

    Diffey, J.L.

    2015-01-01

    The overall diagnostic accuracy of digital mammography in the context of screening has been shown to be similar or slightly better than screen-film mammography. However, digital mammography encompasses both Computed Radiography (CR) and integrated Digital Radiography (DR) and there is increasing evidence to suggest that differences in detector technology are associated with variations in cancer detection rate, dose and image quality. These differences are examined in detail. Although digital mammography offers many advantages compared to screen-film, there are still some limitations with its use as a screening tool and reduced cancer detection in dense breasts remains an issue. Digital mammography detectors have paved the way for emerging technologies which may offer improvements. Taking the definition of mammography to only include X-ray imaging of the breast, this article focuses on tomosynthesis, contrast-enhanced digital mammography, stereoscopic mammography and dedicated breast computed tomography. Advanced software applications such as Computed Aided Detection (CAD) and quantitative breast density assessment are also presented. The benefits and limitations of each technique are discussed. - Highlights: • Digital detector technology affects cancer detection rate, dose and image quality. • Digital detectors have facilitated new technologies such as tomosynthesis. • 3-D techniques reduce superimposition and increase cancer detection in dense breasts. • Contrast-enhanced mammography demonstrates improved sensitivity and specificity.

  9. Comparison of digital radiography and conventional film screen radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kalender, W A; Huebener, K H

    1984-01-01

    Parameters of image quality, comprising spacial resolution and contrast, have been determined in the form of a contrast/detail diagram for a digital system (Topogram) and a film-screen system. The digital system was particularly examined concerning its contrast sensitivity in relation to quantum noise. The clinical implications of the comparison of the systems, where evaluated on chest X-rays of 250 patients. Despite lower image sharpness, the digital method is already able to produce equivalent or better diagnostic results in certain circumstances. The advantages and disadvantages of both systems are discussed in detail.

  10. A comparison of digital radiography and conventional film screen radiography

    International Nuclear Information System (INIS)

    Kalender, W.A.; Huebener, K.H.; Tuebingen Univ.

    1984-01-01

    Parameters of image quality, comprising spacial resolution and contrast, have been determined in the form of a contrast/detail diagram for a digital system (Topogram) and a film-screen system. The digital system was particularly examined concerning its contrast sensitivity in relation to quantum noise. The clinical implications of the comparison of the systems, where evaluated on chest X-rays of 250 patients. Despite lower image sharpness, the digital method is already able to produce equivalent or better diagnostic results in certain circumstances. The advantages and disadvantages of both systems are discussed in detail. (orig.) [de

  11. Experiments on muon radiography with emulsion track detectors

    International Nuclear Information System (INIS)

    Aleksandrov, Andrey; Bagulya, Alexander; Baklagin, Sergei; Chernyavsky, Mikhail; Galkin, Vladimir; Grachev, Victor; Konovalova, Nina; Managadze, Alexander; Polukhina, Natalya; Roganova, Tatiana; Starkov, Nikolai; Shchedrina, Tatiana; Tioukov, Valeri; Vladymirov, Mykhailo; Zemskova, Svetlana

    2016-01-01

    Muon radiography is a method of study the internal structure of large natural and industrial objects based on sensing an object with a flux of cosmic muons with their subsequent registration and analysis of the pattern of their dispersion, or conplete (or partial) absorption. The Lebedev Physical Institute of the Russian Academy of Sciences and the Skobeltsyn Institute of Nuclear Physics of Moscow State University have started a series of muon radiography experiments with nuclear emulsion detectors. As a result, the optimal conditions for experiment arrangement have been determined, algorithms of data processing have been worked out, and peculiarities of the method have been ultimately investigated

  12. WE-G-209-01: Digital Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Schueler, B. [Mayo Clinic (United States)

    2016-06-15

    Digital radiography, CT, PET, and MR are complicated imaging modalities which are composed of many hardware and software components. These components work together in a highly coordinated chain of events with the intent to produce high quality images. Acquisition, processing and reconstruction of data must occur in a precise way for optimum image quality to be achieved. Any error or unexpected event in the entire process can produce unwanted pixel intensities in the final images which may contribute to visible image artifacts. The diagnostic imaging physicist is uniquely qualified to investigate and contribute to resolution of image artifacts. This course will teach the participant to identify common artifacts found clinically in digital radiography, CT, PET, and MR, to determine the causes of artifacts, and to make recommendations for how to resolve artifacts. Learning Objectives: Identify common artifacts found clinically in digital radiography, CT, PET and MR. Determine causes of various clinical artifacts from digital radiography, CT, PET and MR. Describe how to resolve various clinical artifacts from digital radiography, CT, PET and MR.

  13. The scope of detector Medipix2 in micro-radiography of biological samples

    Czech Academy of Sciences Publication Activity Database

    Dammer, J.; Weyda, František; Jakůbek, J.; Škrabal, P.; Sopko, V.; Vavřík, D.

    2011-01-01

    Roč. 633, č. 1 (2011), s. 175-176 ISSN 0168-9002. [International Workshop on Radiation Imaging Detectors /11./. Praha, 29.06.2009-03.07.2009] R&D Projects: GA MŠk 2B06005 Grant - others:Ministerstvo školství(CZ) 6840770040; GA MŠk(CZ) 1P04LA211; GA MŠk(CZ) LC06041 Program:1P; LC Institutional research plan: CEZ:AV0Z50070508 Keywords : x-ray imaging * digital radiography * photon and x-ray detectors Subject RIV: EA - Cell Biology Impact factor: 1.207, year: 2011

  14. Generalized two-dimensional (2D) linear system analysis metrics (GMTF, GDQE) for digital radiography systems including the effect of focal spot, magnification, scatter, and detector characteristics.

    Science.gov (United States)

    Jain, Amit; Kuhls-Gilcrist, Andrew T; Gupta, Sandesh K; Bednarek, Daniel R; Rudin, Stephen

    2010-03-01

    The MTF, NNPS, and DQE are standard linear system metrics used to characterize intrinsic detector performance. To evaluate total system performance for actual clinical conditions, generalized linear system metrics (GMTF, GNNPS and GDQE) that include the effect of the focal spot distribution, scattered radiation, and geometric unsharpness are more meaningful and appropriate. In this study, a two-dimensional (2D) generalized linear system analysis was carried out for a standard flat panel detector (FPD) (194-micron pixel pitch and 600-micron thick CsI) and a newly-developed, high-resolution, micro-angiographic fluoroscope (MAF) (35-micron pixel pitch and 300-micron thick CsI). Realistic clinical parameters and x-ray spectra were used. The 2D detector MTFs were calculated using the new Noise Response method and slanted edge method and 2D focal spot distribution measurements were done using a pin-hole assembly. The scatter fraction, generated for a uniform head equivalent phantom, was measured and the scatter MTF was simulated with a theoretical model. Different magnifications and scatter fractions were used to estimate the 2D GMTF, GNNPS and GDQE for both detectors. Results show spatial non-isotropy for the 2D generalized metrics which provide a quantitative description of the performance of the complete imaging system for both detectors. This generalized analysis demonstrated that the MAF and FPD have similar capabilities at lower spatial frequencies, but that the MAF has superior performance over the FPD at higher frequencies even when considering focal spot blurring and scatter. This 2D generalized performance analysis is a valuable tool to evaluate total system capabilities and to enable optimized design for specific imaging tasks.

  15. Digital luminescence radiography and conventional radiography in abdominal contrast examinations

    International Nuclear Information System (INIS)

    Krug, B.; Harnischmacher, U.; Krahe, T.; Fischbach, R.; Altenburg, A.; Krings, F.

    1995-01-01

    In 326 patients abdominal contrast radiographs were compared to digital luminescence radiographs (DLR) and conventional screen-film system ones. The digital exposure dose was 50% of the conventional. In DLR, 2 different types of postprocessed images were obtained from each data set. A display with low spatial frequency enhancement filtered to look like a conventional radiograph was compared to a display with high spatial frequency enhancement. Conventional and DLR images were evaluated randomly and separately by 4 radiologists by means of a questionnaire. DLR proved to be diagnostically equivalent to the conventional technique with the exception of a slightly diminished visibility of the mucosal pattern. High spatial frequency enhancement did not provide additional diagnostic information and should be dispensed with in abdominal examinations. (orig.)

  16. PROTON RADIOGRAPHY WITH THE PIXEL DETECTOR TIMEPIX

    Directory of Open Access Journals (Sweden)

    Václav Olšanský

    2016-12-01

    Full Text Available This article presents the processing of radiographic data acquired using the position-sensitive hybrid semiconductor pixel detector Timepix. Measurements were made on thin samples at the medical ion-synchrotron HIT [1] in Heidelberg (Germany with a 221 MeV proton beam. The charge is energy by the particles crossing the sample is registered for generation of image contrast. Experimental data from the detector were processed for derivation of the energy loss of each proton using calibration matrices. The interaction point of the protons on the detector were determined with subpixel resolution by model fitting of the individual signals in the pixelated matrix. Three methods were used for calculation of these coordinates: Hough transformation, 2D Gaussian fitting and estimate the 2D mean. Parameters of calculation accuracy and calculation time are compared for each method. The final image was created by method with best parameters.

  17. Digital radiography of the chest: state of the art

    International Nuclear Information System (INIS)

    Souto, M.; Malagari, K.S.; Tucker, D.; Tahoces, P.G.; Correa, J.; Benakis, V.S.; Roussos, C.; Strigaris, K.A.; Vidal, J.J.; Barnes, G.T.; Fraser, R.G.

    1994-01-01

    Digital image acquisition possesses a number of advantages over conventional systems in radiographic examination of the chest, the most important of which is its greater dynamic range. In addition, once digital images are acquired, they can be processed by computer in ways that cannot be rivalled by conventional analog techniques. Finally, digital images can be stored, retrieved and transmitted to local or remote sites. Here the status of the different digital systems employed in chest radiology and commonly used image processing techniques are reviewed. Also discussed are the current clinical applications of integrating digital chest radiography with a picture archiving and communication system (PACS) along with the difficulties typically encountered. Studies with a variety of digital techniques have been carried out on several fronts. Computed radiography based on photostimulable phosphor (CR) has replaced screen-film imaging in certain applications (i.e. bedside imaging). However, CR has limitations, namely its poor X-ray utilisation efficiency at high X-ray tube voltages and sensitivity to scatter; therefore, it is not ideal for all applications. Recently, a dedicated digital chest unit with excellent X-ray utilisation efficiency at high X-ray tube potentials has been introduced. On the basis of the state-of-the-art capabilities and research during the past decade, recommendations are made regarding the most desirable equipment specifications for dedicated and bedside digital chest radiography. (orig.)

  18. A new CCD-camera neutron radiography detector at the Atominstitute of the Austrian Universities

    International Nuclear Information System (INIS)

    Koerner, S.; Boeck, H.; Rauch, H.; Lehmann, E.

    1999-01-01

    Neutron radiography provides a very efficient tool for non-destructive testing as well as for many applications in fundamental research. A neutron beam penetrating a specimen is attenuated by the sample material and detected by a two dimensional imaging device. The image contains information about materials and structure inside the sample because neutrons are attenuated according to the basic law of radiation attenuation. At the Atominstitute of the Austrian Universities neutron radiographic examinations have been carried out for more than 35 years, mainly with detectors consisting of X-ray films and a Gd- converter enclosed in a vacuum cassette. Presently a neutron tomography set-up is under development. For high quality 3D image reconstruction, about 200 digitized neutron transmission images from different angles of the object are necessary. Therefore the first step was the design of an adequate electronic neutron radiography imaging device. The requirements for a detector suitable for neutron tomography are: exact and reproducible positioning, easy handling, high spatial resolution and dynamic range, high efficiency and a good linearity. The key components of the detector system selected on the basis of the requirements consist of a neutron sensitive scintillator screen, a cooled slow scan CCD camera and a mirror to reflect the light emitted by the scintillator to the CCD camera. The whole assembly is placed in a light tight enclosure. In this paper the strategy of the selection of the individual detector components is described. Comparisons on the influence of the use of different components on the properties of the whole position sensitive imaging device are demonstrated. Finally the new CCD camera neutron radiography detector of the Atominstitute is presented and first results of test measurements performed at the neutron radiography facility NEUTRA at the continuous spallation source SINQ at Paul Scherrer Institute are shown.(author)

  19. Application of direct digital radiography of nasal bone

    International Nuclear Information System (INIS)

    Gao Dengfa; Wang Haijun; Zhang Ailian; Wang Yulin

    2005-01-01

    Objective: To research the application value of direct digital radiograph (DDR ) in nasal bone imaging. Methods: One hundred cases were examined by DDR, 30 cases of them were examined by two methods both DDR and conventional radiography. All digital images were post-processed with 'MUSICA' (Multi-Scale Image Contrast Amplification), incision and largamente, analyzed and diagnosed by experienced two radiologists and two technicians. Results: One hundred cases of nasal bone, soft tissue of nose were showed excellent in DDR, and satisfactory cases were 95 and 92, respectively. Forty-six cases of nasal bone fractures were found. Thirty cases were examined by both DDR and conventional radiography, images of nasal bone, soft tissue of nose were showed, satisfactory cases were 28 in DDR; and satisfactory cases were 6 (χ 2 =20.05, P 2 =15.06, P 2 =5.14, P<0.05) in conventional and digital radiography, respectively. Conclusion: DDR images of nasal bone, soft tissue of nose was excellent, more fractures were discovered than conventional radiography. Image quality of DDR is better than conventional radiography in nasal bone imaging. (authors)

  20. Application of digital radiography in the analysis of cultural heritage

    Energy Technology Data Exchange (ETDEWEB)

    Oiveira, Davi F.; Calza, Cristiane; Rocha, Henrique S.; Nascimento, Joseilson R.; Lopes, Ricardo T., E-mail: davi@lin.ufrj.br, E-mail: ccalza@lin.ufrj.br, E-mail: henrique@lin.ufrj.br, E-mail: joseilson@lin.ufrj.br, E-mail: ricardo@lin.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Instrumentacao Nuclear

    2013-07-01

    The scientific examination of artworks has gained increasing interest in the last years, allowing the characterization of materials and techniques employed by the artists. This analysis can be extremely valuable to conservation and restoration treatments. However, the fact that every artworks is a unique piece emphasizes the necessity of working with non-destructive techniques. Although radiography has been used in the technical examination of museum objects for many decades, digital radiography is rapidly becoming a preferred modality for this essential tool in the advanced examination of works of art. The ability to electronically combine images from the large painting into a single composite image file was extremely valuable and results in higher quality images than those achieved with conventional radiography. These images can be also processed and improved using adequate software. Additional advantages of digital radiography include the possibility of an almost immediate analysis of the results, use of an only recording film and absence of chemical processing. Radiographic imaging can be applied to the analysis of virtually all media including paintings, sculptures, woodworks, engravings, etc. This paper reports some case studies of the use of digital radiography in the study of paintings and sculptures, showing the feasibility and advantages of this technique for this kind of purpose. The radiographic images revealed the conservation state of the analyzed objects and various details of its execution in order to assist recently restoration processes. (author)

  1. Application of digital radiography in the analysis of cultural heritage

    International Nuclear Information System (INIS)

    Oiveira, Davi F.; Calza, Cristiane; Rocha, Henrique S.; Nascimento, Joseilson R.; Lopes, Ricardo T.

    2013-01-01

    The scientific examination of artworks has gained increasing interest in the last years, allowing the characterization of materials and techniques employed by the artists. This analysis can be extremely valuable to conservation and restoration treatments. However, the fact that every artworks is a unique piece emphasizes the necessity of working with non-destructive techniques. Although radiography has been used in the technical examination of museum objects for many decades, digital radiography is rapidly becoming a preferred modality for this essential tool in the advanced examination of works of art. The ability to electronically combine images from the large painting into a single composite image file was extremely valuable and results in higher quality images than those achieved with conventional radiography. These images can be also processed and improved using adequate software. Additional advantages of digital radiography include the possibility of an almost immediate analysis of the results, use of an only recording film and absence of chemical processing. Radiographic imaging can be applied to the analysis of virtually all media including paintings, sculptures, woodworks, engravings, etc. This paper reports some case studies of the use of digital radiography in the study of paintings and sculptures, showing the feasibility and advantages of this technique for this kind of purpose. The radiographic images revealed the conservation state of the analyzed objects and various details of its execution in order to assist recently restoration processes. (author)

  2. Efficacy of daily bedside chest radiography as visualized by digital luminescence radiography

    International Nuclear Information System (INIS)

    Kirchner, J.; Stueckle, C.A.; Schilling, E.M.; Peters, J.

    2001-01-01

    To determine the diagnostic impact of daily bedside chest radiography in comparison with digital luminescence technique (DLR; storage phosphor radiography) and conventional film screen radiography, a prospective randomized study was completed in 210 mechanically ventilated patients with a total of 420 analysed radiographs. The patients were allocated to two groups: 150 patients underwent DLR, and 60 patients underwent conventional film screen radiography. Radiological analysis was performed consensually and therapeutic efficacy was assessed by the clinicians. There was no statistical significant difference between the frequency of abnormal findings seen on DLR and conventional film screen radiography. In total, 448 abnormal findings were present in 249 of 300 DLR and 97 of 120 conventional film screen radiographs. The most common findings were signs of overhydration (41 %), pleural effusion (31%), partial collapse of the lung (11%) and pneumothorax (2%). One hundred and twenty-three of 448 (27%) of these abnormal findings were thought to have a considerable impact on patient management. The high rate of abnormal findings with significant impact on patient management suggests that the use of daily bedside chest radiography may be reasonable. Copyright (2001) Blackwell Science Pty Ltd

  3. Digital Radiography and Computed Tomography (DRCT) Product Improvement Plan (PIP)

    Energy Technology Data Exchange (ETDEWEB)

    Tim Roney; Bob Pink; Karen Wendt; Robert Seifert; Mike Smith

    2010-12-01

    The Idaho National Laboratory (INL) has been developing and deploying x-ray inspection systems for chemical weapons containers for the past 12 years under the direction of the Project Manager for Non-Stockpile Chemical Materiel (PMNSCM). In FY-10 funding was provided to advance the capabilities of these systems through the DRCT (Digital Radiography and Computed Tomography) Product Improvement Plan (PIP), funded by the PMNSCM. The DRCT PIP identified three research tasks; end user study, detector evaluation and DRCT/PINS integration. Work commenced in February, 2010. Due to the late start and the schedule for field inspection of munitions at various sites, it was not possible to spend sufficient field time with operators to develop a complete end user study. We were able to interact with several operators, principally Mr. Mike Rowan who provided substantial useful input through several discussions and development of a set of field notes from the Pueblo, CO field mission. We will be pursuing ongoing interactions with field personnel as opportunities arise in FY-11.

  4. Pressure Indication of 3013 Inner Containers Using Digital Radiography

    International Nuclear Information System (INIS)

    HENSEL, SJ

    2004-01-01

    Plutonium bearing materials packaged for long term storage per the Department of Energy Standard 3013 (DOE-STD-3013) are required to be examined periodically in a non-destructive manner (i.e. without compromising the storage containers) for pressure buildup. Radiography is the preferred technology for performing the examinations. The concept is to measure and record the container lid position. As a can pressurizes the lid will deflect outward and thus provide an indication of the internal pressure. A radiograph generated within 30 days of creation of each storage container serves as the baseline from which future surveillance examinations will be compared. A problem with measuring the lid position was discovered during testing of a digital radiography system. The solution was to provide a distinct feature upon the lower surface of the container lid from which the digital radiography system could easily track the lid position

  5. Effective dose in abdominal digital radiography: Patient factor

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Ji Sung; Koo, Hyun Jung; Park, Jung Hoon; Cho, Young Chul; Do, Kyung Hyun [Dept. of Radiology, and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul(Korea, Republic of); Yang, Hyung Jin [Dept. of Medical Physics, Korea University, Seoul (Korea, Republic of)

    2017-08-15

    To identify independent patient factors associated with an increased radiation dose, and to evaluate the effect of patient position on the effective dose in abdominal digital radiography. We retrospectively evaluated the effective dose for abdominal digital radiography in 222 patients. The patients were divided into two groups based on the cut-off dose value of 0.311 mSv (the upper third quartile of dose distribution): group A (n = 166) and group B (n = 56). Through logistic regression, independent factors associated with a larger effective dose were identified. The effect of patient position on the effective dose was evaluated using a paired t-test. High body mass index (BMI) (≥ 23 kg/m2), presence of ascites, and spinal metallic instrumentation were significantly associated with a larger effective dose. Multivariate logistic regression analysis revealed that high BMI [odds ratio (OR), 25.201; p < 0.001] and ascites (OR, 25.132; p < 0.001) were significantly associated with a larger effective dose. The effective dose was significantly lesser (22.6%) in the supine position than in the standing position (p < 0.001). High BMI and ascites were independent factors associated with a larger effective dose in abdominal digital radiography. Significant dose reduction in patients with these factors may be achieved by placing the patient in the supine position during abdominal digital radiography.

  6. Optimization of digital radiography techniques for specific application

    International Nuclear Information System (INIS)

    Harara, W.

    2010-12-01

    A low cost digital radiography system (DRS) for testing weld joints and castings in laboratory was assembled. The DRS is composed from X-ray source, scintillator, first surface mirror with Aluminum coating, charged coupled device (CCD) camera and lens. The DRS was used to test flawed carbon steel welded plates with thicknesses up to 12 mm. The comparison between the digital radiographs of the plates weldments and the radiographs of the same plates weldments using medium speed film type had shown that, the detection capability of the weld flaws are nearly identical for the two radiography techniques, while the sensitivity achieved in digital radiography of the plates weldments was one IQI wire less than the sensitivity achieved by conventional radiography of the same plates weldments according to EN 462-1. Further, the DRS was also successfully used to test (100 x 100 x 100) mm Aluminum casting with artificial flaws of varied dimensions and orientations. The resulted digital radiographs of the casting show that, all the flaws had been detected and their dimensions can be measured accurately, this confirm that, The proposed DRS can be used to detect and measure the flaws in the Aluminum and others light metals castings accurately. (author)

  7. Digital chest radiography: collimation and dose reduction

    DEFF Research Database (Denmark)

    Debess, Jeanne; Johnsen, Karen Kirstine; Vejle-Sørensen, Jens Kristian

    ,3 mAs and SID SID of 180 centimetres using a phantom and lithium fluoride thermo luminescence dosimeter (TLD). Dose to risk organs mamma, thyroid and colon are measured at different collimations with one-centimetre steps. TLD results are used to estimate dose reduction for different collimations...... at the conference. Conclusion: Collimation improvement in basic chest radiography can reduce the radiation to female patients at chest x-ray examinations....

  8. Proton Radiography: Cross Section Measurement and Detector Development

    International Nuclear Information System (INIS)

    Longo, Michael J.

    2007-01-01

    Proton radiography offers significant advantages over conventional X-ray radiography, including the capability of looking into thick, dense materials, better contrast for a wide range of materials, sensitivity to different materials of similar density, and better resolution because of the ability to focus beams. In order to achieve this capability it is crucial to understand the background due to neutrons and photons and to develop techniques to reduce it to tolerable levels. The physics goal of this project is to measure forward production of neutrons and photons produced by high-energy proton beams striking a variety of targets. This work is being carried out in conjunction with the Fermilab Experiment 907 (MIPP) collaboration including physicists from Lawrence Livermore Laboratory. Our group is responsible for the E907 forward neutron/photon calorimeters. These are the only detectors in the experiment that provide information on neutrons and photons. We are taking a leading role in obtaining and analyzing the for-ward production data and in developing an optimal detector for proton radiography. With the support of our Stewardship Science Academic Alliances grant, we were able to design, build, and commission the calorimeters on budget and ahead of schedule. E-907 officially started physics running at Fermilab in January 2005, and data taking continued through February 2006. Data were taken on a range of targets, from liquid hydrogen to uranium, at beam energies from 5 GeV/c to 120 GeV/c. The analysis of the data is challenging because data from many different detector systems must be understood and merged and over 31 million events were accumulated. Our recent efforts have been devoted to the calibration of the neutron and photon detectors, to track and shower reconstruction, identification of forward-going neutrons, and simulation of the calorimeters in a Monte Carlo. Reconstruction of the data with improved tracking is underway

  9. Application of imaging plate neutron detector to neutron radiography

    CERN Document Server

    Fujine, S; Kamata, M; Etoh, M

    1999-01-01

    As an imaging plate neutron detector (IP-ND) has been available for thermal neutron radiography (TNR) which has high resolution, high sensitivity and wide range, some basic characteristics of the IP-ND system were measured at the E-2 facility of the KUR. After basic performances of the IP were studied, images with high quality were obtained at a neutron fluence of 2 to 7x10 sup 8 n cm sup - sup 2. It was found that the IP-ND system with Gd sub 2 O sub 3 as a neutron converter material has a higher sensitivity to gamma-ray than that of a conventional film method. As a successful example, clear radiographs of the flat view for the fuel side plates with boron burnable poison were obtained. An application of the IP-ND system to neutron radiography (NR) is presented in this paper.

  10. Diagnostic value of digital radiography compared to conventional screen-film system combinations

    International Nuclear Information System (INIS)

    Krug, B.; Zaehringer, M.; Lackner, K.

    1997-01-01

    Digital projection radiography provides digital data in X-ray examinations, which used to be carried out by examinations screen-film system combinations. The technological basis and clinical performances of digital luminescent radiography (DLR) and digital radiography are reviewed. Digital projection radiography does not allow to reduce selenium exposure significantly, compared to screen-film system combinations. Digital luminescent radiography can be used for the entire spectrum of analogous projection radiography the only exception being extremely subtile structural changes. The clinical experiences with digital selenium radiography achieved so far in chest X-rays are promising and the technique is expected to be increasing used in other anatomic regions as well. (orig.) [de

  11. High resolution X radiography imaging detector-micro gap chamber

    International Nuclear Information System (INIS)

    Long Huqiang; Wang Yun; Xu Dong; Xie Kuanzhong; Bian Jianjiang

    2007-01-01

    Micro gap chamber (MGC) is a new type of Two-Dimensional position sensitive detector having excellent properties on the space and time resolution, counting rate, 2D compact structure and the flexible of application. It will become a candidate of a new tracking detector for high energy physics experiment. The basic structure and properties of MGC as well as its main research subjects are presented in this paper. Furthermore, the feasibility and validity of utilizing diamond films as the MGC gap material were also discussed in detail. So, a potential radiography imaging detector is provided in order to realize X image and X ray diffraction experiment having very good spatial and time resolution in the 3rd Generation of Synchrotron Radiation Facility. (authors)

  12. Digital X-Radiography Scanning Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Generates digital X-radiographic images of sediment cores that portray density variations, sediment stratigraphy, bioturbation, and inclusions.DESCRIPTION:...

  13. Digital radiography using amorphous selenium: photoconductively activated switch (PAS) readout system.

    Science.gov (United States)

    Reznik, Nikita; Komljenovic, Philip T; Germann, Stephen; Rowlands, John A

    2008-03-01

    A new amorphous selenium (a-Se) digital radiography detector is introduced. The proposed detector generates a charge image in the a-Se layer in a conventional manner, which is stored on electrode pixels at the surface of the a-Se layer. A novel method, called photoconductively activated switch (PAS), is used to read out the latent x-ray charge image. The PAS readout method uses lateral photoconduction at the a-Se surface which is a revolutionary modification of the bulk photoinduced discharge (PID) methods. The PAS method addresses and eliminates the fundamental weaknesses of the PID methods--long readout times and high readout noise--while maintaining the structural simplicity and high resolution for which PID optical readout systems are noted. The photoconduction properties of the a-Se surface were investigated and the geometrical design for the electrode pixels for a PAS radiography system was determined. This design was implemented in a single pixel PAS evaluation system. The results show that the PAS x-ray induced output charge signal was reproducible and depended linearly on the x-ray exposure in the diagnostic exposure range. Furthermore, the readout was reasonably rapid (10 ms for pixel discharge). The proposed detector allows readout of half a pixel row at a time (odd pixels followed by even pixels), thus permitting the readout of a complete image in 30 s for a 40 cm x 40 cm detector with the potential of reducing that time by using greater readout light intensity. This demonstrates that a-Se based x-ray detectors using photoconductively activated switches could form a basis for a practical integrated digital radiography system.

  14. Management of pediatric radiation dose using Canon digital radiography

    International Nuclear Information System (INIS)

    Arreola, M.; Rill, L.

    2004-01-01

    A Canon CXDI-11 digital radiography (DR) system has been in use at Shands Hospital at the University of Florida for the past 2 1/2 years. A first clinical implementation phase was utilized to develop imaging protocols for adult patients, with a second phase incorporating pediatric chest and abdominal studies a few months later. This paper describes some of the steps taken during the modality implementation stages, as well as the methodologies and procedures utilized to monitor compliance by the technologists. The Canon DR system provides the technologist with an indication of the radiation exposure received by the detector (and thus of the patient dose) by means of an indirect exposure level number called the reached exposure (REX) value. The REX value is calculated by the system based on the default grayscale curve preselected for a given anatomical view and used by the system to optimize the appearance of the image. The brightness and contrast of the image can be modified by the user at the QC/control screen for the purpose of improving the appearance of the image. Such changes modify the actual grayscale curve (position and slope, respectively) and thus the calculated REX value. Thus, undisciplined use of the brightness and contrast functions by the technologist can render the REX value meaningless as an exposure indicator. The paper also shows how it is possible to calibrate AEC (phototimer) systems for use with the Canon DR system, and utilize the REX value as a valuable dose indicator through proper training of technologists and strict, disciplined QC of studies. A team consisting of the site's medical physicist, radiologists, and technologists, as well as Canon engineers, can work together in properly calibrating and setting up the system for the purposes of monitoring patient doses (especially pediatric) in DR studies performed in a Canon DR system. (orig.)

  15. Digital radiography in the evaluation of oesophageal motility disorders

    Energy Technology Data Exchange (ETDEWEB)

    Aly, Yehia A

    2000-07-01

    AIMS: To develop a simple technique for examination of the oesophagus by digital radiography and to assess its role in the evaluation of motility disorders of the oesophagus. MATERIALS AND METHODS: Forty-nine patients and 44 control subjects underwent manometry and digital examination of the oesophagus. The digital study consisted of two parts: firstly examination of the pharynx and cervical oesophagus using 15 ml of fluid barium in anterio-posterior (AP) and lateral views, with image acquisition of four frames/s for 2 s. Secondly, examination of the thoracic oesophagus and oesophagogastric junction using 25 ml of barium in two prone oblique and one supine AP series, with image acquisition of one frame/s for 20 s. Oesophageal transit time (OTT) was measured in each case. Abnormal or non-peristaltic contractions were described regarding their morphology, time of visualization and length. The presence or absence of hiatal hernia, reflux or any associated organic lesions was noted. RESULTS: Digital radiography diagnosed 14 cases of achalasia and 28 cases of non-specific oesophageal motility disorder (NOMD). Normal OTT was 11.95 {+-} 1.304 s. The OTT was prolonged (16 s or more) in all patients except five; four of these were cases of NOMD. Abnormal contractions were classified into circular and longitudinal types. The circular non-obliterating type was commoner. Achalasia was diagnosed in all cases, as failure of relaxation of the inferior oesophageal sphincter was always present and easily depicted by digital radiography. Abnormal contractions in the body of the oesophagus were elicited in 57% of cases of achalasia. The sensitivity of digital radiography in detecting oesophageal motility disorders was 85.7% based on the presence of abnormal contractions and 91.6% by eliciting a prolonged OTT. CONCLUSIONS: Examination of the oesophagus by digital radiography is simple, non-invasive, reproducible, rapid and without discomfort to patients. It allows the diagnosis of

  16. Digital radiography in the evaluation of oesophageal motility disorders

    International Nuclear Information System (INIS)

    Aly, Yehia A.

    2000-01-01

    AIMS: To develop a simple technique for examination of the oesophagus by digital radiography and to assess its role in the evaluation of motility disorders of the oesophagus. MATERIALS AND METHODS: Forty-nine patients and 44 control subjects underwent manometry and digital examination of the oesophagus. The digital study consisted of two parts: firstly examination of the pharynx and cervical oesophagus using 15 ml of fluid barium in anterio-posterior (AP) and lateral views, with image acquisition of four frames/s for 2 s. Secondly, examination of the thoracic oesophagus and oesophagogastric junction using 25 ml of barium in two prone oblique and one supine AP series, with image acquisition of one frame/s for 20 s. Oesophageal transit time (OTT) was measured in each case. Abnormal or non-peristaltic contractions were described regarding their morphology, time of visualization and length. The presence or absence of hiatal hernia, reflux or any associated organic lesions was noted. RESULTS: Digital radiography diagnosed 14 cases of achalasia and 28 cases of non-specific oesophageal motility disorder (NOMD). Normal OTT was 11.95 ± 1.304 s. The OTT was prolonged (16 s or more) in all patients except five; four of these were cases of NOMD. Abnormal contractions were classified into circular and longitudinal types. The circular non-obliterating type was commoner. Achalasia was diagnosed in all cases, as failure of relaxation of the inferior oesophageal sphincter was always present and easily depicted by digital radiography. Abnormal contractions in the body of the oesophagus were elicited in 57% of cases of achalasia. The sensitivity of digital radiography in detecting oesophageal motility disorders was 85.7% based on the presence of abnormal contractions and 91.6% by eliciting a prolonged OTT. CONCLUSIONS: Examination of the oesophagus by digital radiography is simple, non-invasive, reproducible, rapid and without discomfort to patients. It allows the diagnosis of

  17. Pelvic measurements by means of digital radiography (CT topogram)

    Energy Technology Data Exchange (ETDEWEB)

    Reisner, K; Fettig, O; Bartscher, K H; Knappschneider, U

    1985-05-01

    Radiographic examination during pregnancy and pelvimetry before pregnancy are still required for particular indications. The use of digital radiography (lateral topogram on CT) reduces the radiation dose to the foetus and ovaries by a factor of 10 to 100, as compared with conventional pelvimetry, as described by Guthmann. The accuracy of this method is satisfactory, the technique is simple, it is rapid and is easy for the patient, particularly for pregnant women. As long as pelvimetry is not possible without ionising radiation, we consider pelvimetry with digital radiography, when strictly indicated, to be acceptable. In order to determine the transverse diameter of the pelvis, a single additional CT cut through the narrowest part of the pelvis is suggested.

  18. Digital subtraction radiography in the study of moving laryngeal structures

    International Nuclear Information System (INIS)

    Perri, G.; Falaschi, F.; Pieri, L.; Esposito, S.; Ursino, F.

    1988-01-01

    Digital subtraction radiography (DSR) was applied to the study of the larynx in 11 healthy subjects and 15 pathological cases. The method, consisting in the subtraction of images obtained at rest and during phonation or respiratory phases, allowed a clear definition of the normal moving structures - i.e. vocal cords, false cords, pyriform sinuses, thyroid cartilage. Moreover, several pathological conditions could be demonstrated. DSR asserts thus itself as a suitable technique in the functional evaluation of glottis

  19. Digital image intensifier radiography: A new diagnostic procedure in traumatology?

    International Nuclear Information System (INIS)

    Schmidt, C.; Deininger, H.K.; Staedtische Kliniken Darmstadt

    1990-01-01

    Digital image intensifier radiography visualises all traumatological changes of clinical relevance and can therefore be used in traumatology. However, the quality of conventional radiographs cannot be attained as yet. Radiation exposure is markedly reduced, and radiographs are obtained directly after exposure, so that this is an extremely rapid radiographic procedure. Images can be quickly transmitted by video cable to the relevant departments and working places. (orig.) [de

  20. Digital computed radiography in industrial X-ray testing

    International Nuclear Information System (INIS)

    Osterloh, K.; Onel, Y.; Zscherpel, U.; Ewert, U.

    2001-01-01

    Computed radiography is used for X-ray testing in many industrial applications. There are different systems depending on the application, e.g. fast systems for detection of material inhomogeneities and slower systems with higher local resolution for detection of cracks and fine details, e.g. in highly stressed areas or in welded seams. The method is more dynamic than film methods, and digital image processing is possible during testing [de

  1. Photon counting detector for the personal radiography inspection system “SIBSCAN”

    Energy Technology Data Exchange (ETDEWEB)

    Babichev, E.A.; Baru, S.E. [Budker Institute of Nuclear Physics, Lavrentiev ave. 11, Novosibirsk 630090 (Russian Federation); Grigoriev, D.N. [Budker Institute of Nuclear Physics, Lavrentiev ave. 11, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Pirogova st. 2, Novosibirsk 630090 (Russian Federation); Novosibirsk State Technical University, 20 Prospekt K. Marksa, Novosibirsk 630073 (Russian Federation); Leonov, V.V. [Budker Institute of Nuclear Physics, Lavrentiev ave. 11, Novosibirsk 630090 (Russian Federation); Oleynikov, V.P. [Budker Institute of Nuclear Physics, Lavrentiev ave. 11, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Pirogova st. 2, Novosibirsk 630090 (Russian Federation); Porosev, V.V., E-mail: porosev@inp.nsk.su [Budker Institute of Nuclear Physics, Lavrentiev ave. 11, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Pirogova st. 2, Novosibirsk 630090 (Russian Federation); Savinov, G.A. [Budker Institute of Nuclear Physics, Lavrentiev ave. 11, Novosibirsk 630090 (Russian Federation)

    2017-02-11

    X-ray detectors operating in the energy integrating mode are successfully used in many different applications. Nevertheless the direct photon counting detectors, having the superior parameters in comparison with the integrating ones, are rarely used yet. One of the reasons for this is the low value of the electrical signal generated by a detected photon. Silicon photomultiplier (SiPM) based scintillation counters have a high detection efficiency, high electronic gain and compact dimensions. This makes them a very attractive candidate to replace routinely used detectors in many fields. More than 10 years ago the digital scanning radiography system based on multistrip ionization chamber (MIC) was suggested at Budker Institute of Nuclear Physics. The detector demonstrates excellent radiation resistance and parameter stability after 5 year operations and an imaging of up to 1000 persons per day. Currently, the installations operate at several Russian airports and at subway stations in some cities. At the present time we design a new detector operating in the photon counting mode, having superior parameters than the gas one, based on scintillator – SiPM assemblies. This detector has close to zero noise, higher quantum efficiency and a count rate capability of more than 5 MHz per channel (20% losses), which leads to better image quality and improved detection capability. The suggested detector technology could be expanded to medical applications.

  2. Photon counting detector for the personal radiography inspection system “SIBSCAN”

    International Nuclear Information System (INIS)

    Babichev, E.A.; Baru, S.E.; Grigoriev, D.N.; Leonov, V.V.; Oleynikov, V.P.; Porosev, V.V.; Savinov, G.A.

    2017-01-01

    X-ray detectors operating in the energy integrating mode are successfully used in many different applications. Nevertheless the direct photon counting detectors, having the superior parameters in comparison with the integrating ones, are rarely used yet. One of the reasons for this is the low value of the electrical signal generated by a detected photon. Silicon photomultiplier (SiPM) based scintillation counters have a high detection efficiency, high electronic gain and compact dimensions. This makes them a very attractive candidate to replace routinely used detectors in many fields. More than 10 years ago the digital scanning radiography system based on multistrip ionization chamber (MIC) was suggested at Budker Institute of Nuclear Physics. The detector demonstrates excellent radiation resistance and parameter stability after 5 year operations and an imaging of up to 1000 persons per day. Currently, the installations operate at several Russian airports and at subway stations in some cities. At the present time we design a new detector operating in the photon counting mode, having superior parameters than the gas one, based on scintillator – SiPM assemblies. This detector has close to zero noise, higher quantum efficiency and a count rate capability of more than 5 MHz per channel (20% losses), which leads to better image quality and improved detection capability. The suggested detector technology could be expanded to medical applications.

  3. Digital radiography: spatial and contrast resolution

    Science.gov (United States)

    Bjorkholm, Paul; Annis, M.; Frederick, E.; Stein, J.; Swift, R.

    1981-07-01

    The addition of digital image collection and storage to standard and newly developed x-ray imaging techniques has allowed spectacular improvements in some diagnostic procedures. There is no reason to expect that the developments in this area are yet complete. But no matter what further developments occur in this field, all the techniques will share a common element, digital image storage and processing. This common element alone determines some of the important imaging characteristics. These will be discussed using one system, the Medical MICRODOSE System as an example.

  4. Digital contrast subtraction radiography for proximal caries diagnosis

    International Nuclear Information System (INIS)

    Kang, Byung Cheol; Yoon, Suk Ja

    2002-01-01

    To determine whether subtraction images utilizing contrast media can improve the diagnostic performance of proximal caries diagnosis compared to conventional periapical radiographic images. Thirty-six teeth with 57 proximal surfaces were radiographied using a size no.2 RVG-ui sensor (Trophy Radiology, Marne-la-Vallee, France). The teeth immersed in water-soluble contrast media and subtraction images were taken. Each tooth was then sectioned for histologic examination. The digital radiographic images and subtraction images were examined and interpreted by three dentists for proximal caries. The results of the proximal caries diagnosis were then verified with the results of the histologic examination. The proximal caries sensitivity using digital subtraction radiography was significantly higher than simply examining a single digital radiograph. The sensitivity of the proximal dentinal carious lesion when analyzed with the subtraction radiograph and the radiograph together was higher than with the subtraction radiograph or the radiograph alone. The use of subtraction radiography with contrast media may be useful for detecting proximal dentinal carious lesions.

  5. Digital luminescence radiography of the chest

    International Nuclear Information System (INIS)

    Kehler, M.

    1991-10-01

    The aim of the present study was to evaluate the efficacy of a digital system in chest radiology compared to the conventional film-screen system. The first studies (1-3) were purely clinical, had two parts, one clinical and one using phantoms, and the 5:th used solely phantoms. Except for the first - pilot - study, the studies were performed as receiver operating characteristic (ROC) analysis. From one exposure, two digital radiographs were obtained, one simulating the film-screen radiograph and one enhanced, using an unsharp mask. The conventional radiograph was compared to this double-image, but in addition to this, even to the simulated normal and enhanced separately (1-3). To evaluate the value of inverted (positive) radiographs, the original digital (negative) radiographs were inverted, and then compared to the originals (4). As digitzation means easy storing and transfer of data and possibility of electronic display, the diagnostic performance of an interactive workstation was assessed (5). In the clinical studies, a variety of chest affections were used: atelectasis, tumor, pneumothorax, fibrosis, mediastinal and bony changes, tuberculosis, incompensations and enlargement of the heart (1), pneumothorax (2), fibrosis (3), and tumor (4). In the phantom studies, test objects simulating tumors (4) and pneumothorax (5) were used. In no study was statistical significant difference seen between the digital and conventional system (p>0.05). Neither in the clinical nor the phantom study did inversion of the radiographs improve diagnostic performance. The workstation performed almost equally well as the radiographs even with a resolution of 1.25 1p/mm compared to the digital radiographs 2.5 and film-screen radiographs 5 1p/mm. (au) (50 refs.)

  6. Direct digital conversion detector technology

    Science.gov (United States)

    Mandl, William J.; Fedors, Richard

    1995-06-01

    Future imaging sensors for the aerospace and commercial video markets will depend on low cost, high speed analog-to-digital (A/D) conversion to efficiently process optical detector signals. Current A/D methods place a heavy burden on system resources, increase noise, and limit the throughput. This paper describes a unique method for incorporating A/D conversion right on the focal plane array. This concept is based on Sigma-Delta sampling, and makes optimum use of the active detector real estate. Combined with modern digital signal processors, such devices will significantly increase data rates off the focal plane. Early conversion to digital format will also decrease the signal susceptibility to noise, lowering the communications bit error rate. Computer modeling of this concept is described, along with results from several simulation runs. A potential application for direct digital conversion is also reviewed. Future uses for this technology could range from scientific instruments to remote sensors, telecommunications gear, medical diagnostic tools, and consumer products.

  7. Detectability of the mediastinal lines : comparison of conventional film-screen radiography and digital radiography

    International Nuclear Information System (INIS)

    Shin, Hye Young; Park, Kyung Joo; Kang, Doo Kyung; Lee, Kang Lai; Han, Chaing Jin; Suh, Jung Ho

    1998-01-01

    Using dynamic range compression (DRC) processing, this study compared the detectability of mediastinal lines by conventional film screen radiography (FS) and by storage phosphor digital radiography (DR). We selected 200 normal consecutive chest radiographs (100 FS, 100 DR); dynamic range compression was applied to DR processing and moving grids were used in both systems. Seven mediastinal lines (left paraspinal, right paraspinal, azygoesophageal, left para-aortic, posterio junctional, anterior junctional and right paratracheal) were scored from 0 point to 3 point (0: not visible, 1 : suspiciously visible, 2 : visible, but not clear, 3: clearly visible) according to visibility and sharpness, as agreed by a radiologist and a resident. The differences between the two modalities were compared and analyzed by chi-square test. DR processed with DRC visualizes mediastinal lines more frequently and clearly than conventional FS, and is therefore thought to be useful for the evaluation of mediastinal diseases. (author). 14 refs., 2 tabs., 2 figs

  8. Pediatric digital radiography education for radiologic technologists: current state

    International Nuclear Information System (INIS)

    Morrison, Gregory; Culbertson, John; Carbonneau, Kira; John, Susan D.; Goske, Marilyn J.; Smith, Susan N.; Charkot, Ellen; Herrmann, Tracy

    2011-01-01

    Digital radiography (DR) is one of several new products that have changed our work processes from hard copy to digital formats. The transition from analog screen-film radiography to DR requires thorough user education because of differences in image production, processing, storage and evaluation between the forms of radiography. Without adequate education, radiologic technologists could unknowingly expose children to higher radiation doses than necessary for adequate radiograph quality. To evaluate knowledge about image quality and dose management in pediatric DR among radiologic technologists in the U.S. This communication describes a survey of 493 radiologic technologists who are members of the American Society of Radiologic Technologists (ASRT) and who evaluated the current state of radiological technologist education in image quality and dose management in pediatric DR. The survey included 23 survey questions regarding image acquisition issues, quality assurance, radiation exposure and education in DR of infants and children. Radiologic technologists express many needs in areas of training and education in pediatric DR. Suggested improvements include better tools for immediate feedback about image quality and exposure, more information about appropriate technique settings for pediatric patients, more user-friendly vendor manuals and educational materials, more reliable measures of radiation exposure to patients, and more regular and frequent follow-up by equipment vendors. There is a clear and widespread need for comprehensive and practical education in digital image technology for radiologic technologists, especially those engaged in pediatric radiography. The creation of better educational materials and training programs, and the continuation of educational opportunities will require a broad commitment from equipment manufacturers and vendors, educational institutions, pediatric radiology specialty organizations, and individual imaging specialists. (orig.)

  9. Digital luminescence radiography using a chest phantom

    International Nuclear Information System (INIS)

    Lyttkens, K.; Kehler, M.; Andersson, B.; Carlsen, S.; Ebbesen, A.; Hochbergs, P.; Stroembaeck, A.

    1993-01-01

    With the introduction of picture and archiving communicating systems an alternative image display for the wards might be a personal computer (PC). The intention with this study was to evaluate the diagnostic image quality of the monitor of a PC compared to that of a workstation. Eighty-five digital radiographs of a chest phantom with simulated tumors in the mediastinum and right lung were saved on optical discs. The examinations were reviewed by 4 radiologists on a monitor at a workstation and at a PC, and receiver operating characteristic (ROC) curves were constructed. No significant difference was found between performance of the PC and the workstation. (orig.)

  10. Digital image processing for radiography in nuclear power plants

    International Nuclear Information System (INIS)

    Heidt, H.; Rose, P.; Raabe, P.; Daum, W.

    1985-01-01

    With the help of digital processing of radiographic images from reactor-components it is possible to increase the security and objectiveness of the evaluation. Several examples of image processing procedures (contrast enhancement, density profiles, shading correction, digital filtering, superposition of images etc.) show the advantages for the visualization and evaluation of radiographs. Digital image processing can reduce some of the restrictions of radiography in nuclear power plants. In addition a higher degree of automation can be cost-saving and increase the quality of radiographic evaluation. The aim of the work performed was to to improve the readability of radiographs for the human observer. The main problem is lack of contrast and the presence of disturbing structures like weld seams. Digital image processing of film radiographs starts with the digitization of the image. Conventional systems use TV-cameras or scanners and provide a dynamic range of 1.5. to 3 density units, which are digitized to 256 grey levels. For the enhancement process it is necessary that the grey level range covers the density range of the important regions of the presented film. On the other hand the grey level coverage should not be wider than necessary to minimize the width of digitization steps. Poor digitization makes flaws and cracks invisible and spoils all further image processing

  11. Evaluation of diagnostic ability of CCD digital radiography in the detection of incipient dental caries

    International Nuclear Information System (INIS)

    Lee, Wan; Lee, Byung Do

    2003-01-01

    The purpose of this experiment was to evaluate the diagnostic ability of a CCD-based digital system (CDX-2000HQ) in the detection of incipient dental caries. 93 extracted human teeth with sound proximal surfaces and interproximal artificial cavities were radiographed using 4 imaging methods. Automatically processed No.2 Insight film (Eastman Kodak Co., U.S.A.) was used for conventional radiography, scanned images of conventional radiograms for indirect digital radiography were used. For the direct digital radiography, the CDX-2000HQ CCD system (Biomedisys Co. Korea) was used. The subtraction images were made from two direct digital images by Sunny program in the CDX-2000HQ system. Two radiologists and three endodontists examined the presence of lesions using a five-point confidence scale and compared the diagnostic ability by ROC (Receiver Operating Characteristic) analysis and one way ANOVA test. The mean ROC areas of conventional radiography, indirect digital radiography, direct digital radiography, and digital subtraction radiography were 0.9093, 0.9102, 0.9184, and 0.9056, respectively. The diagnostic ability of direct digital radiography was better than the other imaging modalities, but there were no statistical differences among these imaging modalities (p>0.05). These results indicate that new CCD-based digital systems (CDX-2000HQ) have the potential to serve as an alternative to conventional radiography in the detection of incipient dental caries.

  12. A new scanner for in situ digital radiography of paintings

    Energy Technology Data Exchange (ETDEWEB)

    Impallaria, Anna; Petrucci, Ferruccio; Tisato, Flavia [University of Ferrara, Department of Physics and Earth Science, Ferrara (Italy); TekneHub Ferrara, Ferrara (Italy); INFN-Sezione di Ferrara, Ferrara (Italy); Evangelisti, Federico [University of Ferrara, Department of Physics and Earth Science, Ferrara (Italy); INFN-Sezione di Ferrara, Ferrara (Italy); Castelli, Lisa; Taccetti, Francesco [INFN-Sezione di Firenze, Sesto Fiorentino (Italy)

    2016-12-15

    X-ray radiography is one of the most widely used imaging techniques in the field of cultural heritage, both for conservation and for investigation purposes. Performing radiographies in museums, thus avoiding movements of works of art, has been recently made easy by digital acquisition of images, but when the whole scan of a large painting is required, technical solutions for a portable device are still not at hand. The inherent weight of the X-ray tube and of the high-voltage generator makes the design of a portable device very difficult. In this project, the solution of the puzzle was separating devices devoted to different tasks, in order to maintain each item under 60 kg weight, thus being transportable with reasonable effort. (orig.)

  13. A new scanner for in situ digital radiography of paintings

    International Nuclear Information System (INIS)

    Impallaria, Anna; Petrucci, Ferruccio; Tisato, Flavia; Evangelisti, Federico; Castelli, Lisa; Taccetti, Francesco

    2016-01-01

    X-ray radiography is one of the most widely used imaging techniques in the field of cultural heritage, both for conservation and for investigation purposes. Performing radiographies in museums, thus avoiding movements of works of art, has been recently made easy by digital acquisition of images, but when the whole scan of a large painting is required, technical solutions for a portable device are still not at hand. The inherent weight of the X-ray tube and of the high-voltage generator makes the design of a portable device very difficult. In this project, the solution of the puzzle was separating devices devoted to different tasks, in order to maintain each item under 60 kg weight, thus being transportable with reasonable effort. (orig.)

  14. Digital image intensifier radiography. One year's experience with a Polytron system

    International Nuclear Information System (INIS)

    Busch, H.P.; Lehmann, K.J.; Georgi, M.

    1989-01-01

    Since January 1988, digital image intensifier radiography has been used in the Clinic in Mannheim for DSA examinations and also in place of conventional screen/film examinations. Measurements have shown that compared with 100 mm and film/screen formats, digital radiography has poorer spatial resolution, but improved contrast resolution. The most common use of digital radiography was for examinations of the gastrointestinal tract. Using the demonstration of the mucosal fine relief pattern as a criterion of image quality, digital image intensifier radiography was able to achieve this satisfactorily. Comparison with film/screen examinations showed no loss of diagnostic information. Advantages of image intensifier radiography are reduced radiation dose, the possibility of postprocessing and economy. On the basis of 399 examinations, digital image intensifier radiography is now firmly established as part of the daily routine of the Mannheim Clinic. (orig.) [de

  15. Digital luminescent radiography for diagnosis of skeletal injuries

    International Nuclear Information System (INIS)

    Buddenbrock, B.; Mueller, R.D.; John, V.; Kock, H.J.; Hirche, H.; Voss, M.; Loehr, E.; Schmit-Neuerburg, K.P.

    1992-01-01

    In the course of a comparative study 231 patients with traumatic lesions in skeletal and soft tissue areas were X-rayed using conventional film radiography and digital luminescence radiography (DLR). The results were evaluated by radiologists and traumatologists on the basis of optimised image post-processing in addition to the standard digital presentations. The imaging quality of compacta, spongiosa, soft tissues, fracture lines and osteosynthesis material was assessed in comparison with the screen-film images. Whereas the standard digital presentation in the ''conventionally adjusted'' imaging mode was inferior to the screen-film radiograph, the ''edge-enhanced'' standard presentation proved to be advantageous in the imaging of soft tissues (frequency of first-place ratings: DLR conventional 6%, screen-film system 21%, DLR edge-enhanced 31%). In the overall evaluation high-frequency filtered inverse image post-processing showed the highest diagnostic potential (frequency of first-place ratings: 41%). A conclusive assessment of metal implants is hindered by overshoot artefacts and can only be achieved through time-consuming post-processing of the stored image data. (orig.)

  16. A note on digital dental radiography in forensic odontology.

    Science.gov (United States)

    Chiam, Sher-Lin

    2014-09-01

    Digital dental radiography, intraoral and extraoral, is becoming more popular in dental practice. It offers convenience, such as lower exposure to radiation, ease of storing of images, and elimination of chemical processing. However, it also has disadvantages and drawbacks. One of these is the potential for confusion of the orientation of the image. This paper outlines one example of this, namely, the lateral inversion of the image. This source of confusion is partly inherent in the older model of phosphor storage plates (PSPs), as they allow both sides to be exposed without clue to the fact that the image is acquired on the wrong side. The native software allows digital manipulation of the X-ray image, permitting both rotation and inversion. Attempts to orientate the X-ray according to the indicator incorporated on the plate can then sometimes lead to inadvertent lateral inversion of the image. This article discusses the implications of such mistakes in dental digital radiography to forensic odontology and general dental practice.

  17. A survey of digital radiography practice in four South African teaching hospitals: an illuminative study.

    Science.gov (United States)

    Nyathi, T; Chirwa, Tf; van der Merwe, Dg

    2010-01-01

    The purpose of this study was to assess radiographer familiarity and preferences with digital radiography in four teaching hospitals and thereafter make recommendations in line with the migration from screen film to digital radiography. A questionnaire was designed to collect data from either qualified or student radiographers from four teaching hospitals. From the four teaching hospitals, there were a total of 205 potential respondents. Among other things, responses regarding experiences and preferences with digital radiography, quality control procedures, patient dose, advantages and disadvantages of digital radiography were sought. The information collected was based on self-reporting by the participants. The study is exploratory in nature and descriptive statistics were generated from the collected data using Microsoft Excel 2007 and StatsDirect software. Sixty-three out of 205 (31%) radiographers from all the four radiology centers responded to the circulated questionnaire. Only 15% (8) of the qualified radiographers had 4 or more years of experience with digital radiography compared to 68% (36) for the same amount of experience with screen-film radiography. Sixty-one percent (38) of the participants had been exposed to digital radiography during their lectures while at university. A small proportion, 16% (10) of the respondents underwent formal training in quality control procedures on the digital X-ray units they were using. Slightly more than half (55%) of the participants felt it was easier for them to retake an image in digital radiography than in screen film radiography. The results of this survey showed that the participants are familiar with digital radiography and have embraced this relatively new technology as shown by the fact that they can identify both its advantages and disadvantages as applied to clinical practice. However, there are minimal quality control procedures specific to digital radiography being undertaken as such there is need for

  18. Automatic analysis of quality of images from X-ray digital flat detectors

    International Nuclear Information System (INIS)

    Le Meur, Y.

    2009-04-01

    Since last decade, medical imaging has grown up with the development of new digital imaging techniques. In the field of X-ray radiography, new detectors replace progressively older techniques, based on film or x-ray intensifiers. These digital detectors offer a higher sensibility and reduced overall dimensions. This work has been prepared with Trixell, the world leading company in flat detectors for medical radiography. It deals with quality control on digital images stemming from these detectors. High quality standards of medical imaging impose a close analysis of the defects that can appear on the images. This work describes a complete process for quality analysis of such images. A particular focus is given on the detection task of the defects, thanks to methods well adapted to our context of spatially correlated defects in noise background. (author)

  19. Comparison of the diagnostic accuracy of direct digital radiography system, filtered images, and subtraction radiography

    Directory of Open Access Journals (Sweden)

    Wilton Mitsunari Takeshita

    2013-01-01

    Full Text Available Background: To compare the diagnostic accuracy of three different imaging systems: Direct digital radiography system (DDR-CMOS, four types of filtered images, and a priori and a posteriori registration of digital subtraction radiography (DSR in the diagnosis of proximal defects. Materials and Methods: The teeth were arranged in pairs in 10 blocks of vinyl polysiloxane, and proximal defects were performed with drills of 0.25, 0.5, and 1 mm diameter. Kodak RVG 6100 sensor was used to capture the images. A posteriori DSR registrations were done with Regeemy 0.2.43 and subtraction with Image Tool 3.0. Filtered images were obtained with Kodak Dental Imaging 6.1 software. Images (n = 360 were evaluated by three raters, all experts in dental radiology. Results: Sensitivity and specificity of the area under the receiver operator characteristic (ROC curve (Az were higher for DSR images with all three drills (Az = 0.896, 0.979, and 1.000 for drills 0.25, 0.5, and 1 mm, respectively. The highest values were found for 1-mm drills and the lowest for 0.25-mm drills, with negative filter having the lowest values of all (Az = 0.631. Conclusion: The best method of diagnosis was by using a DSR. The negative filter obtained the worst results. Larger drills showed the highest sensitivity and specificity values of the area under the ROC curve.

  20. Need for New Optimisation Strategies in CR and Direct Digital Radiography

    International Nuclear Information System (INIS)

    Busch, H.P.

    2000-01-01

    Digital imaging techniques such as Digital Image Intensifier Radiography and Digital Storage Phosphor (Selenium) Radiography are replacing conventional film-screen radiography more and more. The aim of this development is the extension of diagnostic capabilities and the reduction of side effects such as radiation dose. Conventional film-screen radiography and digital radiography are very different ways of imaging. For digital radiography specific post-processing is the link between imaging conditions and film documentation. Optimisation of the images includes new possibilities of post-processing and a broad range for variation of the dose. Especially in fluoroscopy, dose can be reduced significantly by new technical features like pulsed fluoroscopy. For digital radiography the European guidelines on quality criteria have to be applied to projection radiography, digital subtraction radiography and to fluoroscopy. Further work should lead to a definition of reference values for the dose and the image quality. This has to be done first for single exposures and fluoroscopic mode and secondly for diagnostic and interventional procedures. (author)

  1. Digital chest radiography: an update on modern technology, dose containment and control of image quality

    International Nuclear Information System (INIS)

    Schaefer-Prokop, Cornelia; Venema, Henk W.; Neitzel, Ulrich; Uffmann, Martin; Prokop, Mathias

    2008-01-01

    The introduction of digital radiography not only has revolutionized communication between radiologists and clinicians, but also has improved image quality and allowed for further reduction of patient exposure. However, digital radiography also poses risks, such as unnoticed increases in patient dose and suboptimum image processing that may lead to suppression of diagnostic information. Advanced processing techniques, such as temporal subtraction, dual-energy subtraction and computer-aided detection (CAD) will play an increasing role in the future and are all targeted to decrease the influence of distracting anatomic background structures and to ease the detection of focal and subtle lesions. This review summarizes the most recent technical developments with regard to new detector techniques, options for dose reduction and optimized image processing. It explains the meaning of the exposure indicator or the dose reference level as tools for the radiologist to control the dose. It also provides an overview over the multitude of studies conducted in recent years to evaluate the options of these new developments to realize the principle of ALARA. The focus of the review is hereby on adult applications, the relationship between dose and image quality and the differences between the various detector systems. (orig.)

  2. Effects of optimization and image processing in digital chest radiography

    International Nuclear Information System (INIS)

    Kheddache, S.; Maansson, L.G.; Angelhed, J.E.; Denbratt, L.; Gottfridsson, B.; Schlossman, D.

    1991-01-01

    A digital system for chest radiography based on a large image intensifier was compared to a conventional film-screen system. The digital system was optimized with regard to spatial and contrast resolution and dose. The images were digitally processed for contrast and edge enhancement. A simulated pneumothorax and two and two simulated nodules were positioned over the lungs and the mediastinum of an anthro-pomorphic phantom. Observer performance was evaluated with Receiver Operating Characteristic (ROC) analysis. Five observers assessed the processed digital images and the conventional full-size radiographs. The time spent viewing the full-size radiographs and the digital images was recorded. For the simulated pneumothorax, the results showed perfect performance for the full-size radiographs and detectability was high also for the processed digital images. No significant differences in the detectability of the simulated nodules was seen between the two imaging systems. The results for the digital images showed a significantly improved detectability for the nodules in the mediastinum as compared to a previous ROC study where no optimization and image processing was available. No significant difference in detectability was seen between the former and the present ROC study for small nodules in the lung. No difference was seen in the time spent assessing the conventional full-size radiographs and the digital images. The study indicates that processed digital images produced by a large image intensifier are equal in image quality to conventional full-size radiographs for low-contrast objects such as nodules. (author). 38 refs.; 4 figs.; 1 tab

  3. Digital chest radiography: an update on modern technology, dose containment and control of image quality

    NARCIS (Netherlands)

    Schaefer-Prokop, Cornelia; Neitzel, Ulrich; Venema, Henk W.; Uffmann, Martin; Prokop, Mathias

    2008-01-01

    The introduction of digital radiography not only has revolutionized communication between radiologists and clinicians, but also has improved image quality and allowed for further reduction of patient exposure. However, digital radiography also poses risks, such as unnoticed increases in patient dose

  4. Digital radiography in tomography of the facial part of the skull

    International Nuclear Information System (INIS)

    Ibing, H.P.; Vogel, H.; Biebesheimer, V.

    1988-01-01

    In 14 patients the X-ray findings of dental, mandibulary and maxillary roentgen diagnosis were compared with conventional tomography and tomography by digital radiography. All details important for diagnosis were shown by both techniques. Tomography by digital radiography offered a more convenient approach and pictures easier to be interpreted than pictures by conventional tomography. (orig.) [de

  5. A preliminary design of mechanical device on industrial digital radiography equipment design

    International Nuclear Information System (INIS)

    Nur Khasan; Samuel Praptoyo

    2015-01-01

    A preliminary design of mechanical device on industrial digital radiography equipment has been done. this design is intended as a basis for the manufacture of complete facilities for the realization a prototype on industrial digital radiography equipment. the design and construction were carried out by paying attention to the general configuration of the basic design in which its mechanical design has several components with specific dimensions and heavy mass. this design consist of a main frame holder, flat panel detector support and hydraulic hand stacker for mounting the x-ray machine. this mechanical device design will then be fabricated to facilitate and assist work of digital radiographic retrieval. computer application programs sketch-up is used to draw this design and the analysis stress of autodesk inventor to analysis the strength construction design. the results of this design are the configuration drawing, sketch drawings of construction and the safety factor of construction design with a minimum value of 2.39 as well as a maximum value of 15 when to be simulated by the load 500 Kg which is 4 times of total workload. (author)

  6. Application of Digital Radiography to Weld Inspection for the Space Shuttle External Fuel Tank

    Science.gov (United States)

    Ussery, Warren

    2009-01-01

    This slide presentation reviews NASA's use of digital radiography to inspect the welds of the external tanks used to hold the cryogenic fuels for the Space Shuttle Main Engines. NASA has had a goal of replacing a significant portion of film used to inspect the welds, with digital radiography. The presentation reviews the objectives for converting to a digital system from film, the characteristics of the digital system, the Probability of detection study, the qualification and implementation of the system.

  7. Quantitative evaluation of anatomical noise in chest digital tomosynthesis, digital radiography, and computed tomography

    International Nuclear Information System (INIS)

    Lee, D.; Kim, D.; Choi, S.; Kim, H.-J.; Choi, S.; Lee, H.

    2017-01-01

    Lung cancer is currently the worldwide leading cause of death from cancer. Thus, detection of lung cancer at its early stages is critical for improving the survival rate of patients. Chest digital tomosynthesis (CDT) is a recently developed imaging modality, combining many advantages of digital radiography (DR) and computed tomography (CT). This method has the potential to be widely used in the clinical setting. In this study, we introduce a developed CDT R/F system and compare its image quality with those of DR and CT, especially with respect to anatomical noise and lung nodule conspicuity, for LUNGMAN phantoms. The developed CDT R/F system consists of a CsI scintillator flat panel detector, X-ray tube, and tomosynthesis data acquisition geometry. For CDT R/F imaging, 41 projections were acquired at different angles, over the ± 20° angular range, in a linear translation geometry. To evaluate the clinical effectiveness of the CDT R/F system, the acquired images were compared with CT (Philips brilliance CT 64, Philips healthcare, U.S.) and DR (ADR-M, LISTEM, Korea) phantom images in terms of the anatomical noise power spectrum (aNPS). DR images exhibited low conspicuity for a small-size lung nodule, while CDT R/F and CT exhibited relatively high sensitivity for all lung nodule sizes. The aNPS of the CDT R/F system was better than that of DR, by resolving anatomical overlapping problems. In conclusion, the developed CDT R/F system is likely to contribute to early diagnosis of lung cancer, while requiring a relatively low patient dose, compared with CT.

  8. Quantitative evaluation of anatomical noise in chest digital tomosynthesis, digital radiography, and computed tomography

    Science.gov (United States)

    Lee, D.; Choi, S.; Lee, H.; Kim, D.; Choi, S.; Kim, H.-J.

    2017-04-01

    Lung cancer is currently the worldwide leading cause of death from cancer. Thus, detection of lung cancer at its early stages is critical for improving the survival rate of patients. Chest digital tomosynthesis (CDT) is a recently developed imaging modality, combining many advantages of digital radiography (DR) and computed tomography (CT). This method has the potential to be widely used in the clinical setting. In this study, we introduce a developed CDT R/F system and compare its image quality with those of DR and CT, especially with respect to anatomical noise and lung nodule conspicuity, for LUNGMAN phantoms. The developed CDT R/F system consists of a CsI scintillator flat panel detector, X-ray tube, and tomosynthesis data acquisition geometry. For CDT R/F imaging, 41 projections were acquired at different angles, over the ± 20° angular range, in a linear translation geometry. To evaluate the clinical effectiveness of the CDT R/F system, the acquired images were compared with CT (Philips brilliance CT 64, Philips healthcare, U.S.) and DR (ADR-M, LISTEM, Korea) phantom images in terms of the anatomical noise power spectrum (aNPS). DR images exhibited low conspicuity for a small-size lung nodule, while CDT R/F and CT exhibited relatively high sensitivity for all lung nodule sizes. The aNPS of the CDT R/F system was better than that of DR, by resolving anatomical overlapping problems. In conclusion, the developed CDT R/F system is likely to contribute to early diagnosis of lung cancer, while requiring a relatively low patient dose, compared with CT.

  9. Flat panel detectors - closing the (digital) gap in chest and skeletal radiology

    International Nuclear Information System (INIS)

    Reiff, Kurt J.

    1999-01-01

    In the radiological department today the majority of all X-ray procedures on chest and skeletal radiography is performed with classical film-screen-systems. Using digital luminescence radiography (DLR or CR, which stands for Computed Radiography) as a technique has shown a way to replace this 100-year-old procedure of doing general radiography work by acquiring the X-rays digitally via phosphor screens, but this approach has faced criticism from lots of radiologists world wide and therefore has not been widely accepted except in the intensive care environment. A new technology is now rising based on the use of so called flat panel X-ray (FD) detectors. Semi-conducting material detects the X-rays in digital form directly and creates an instantaneous image for display, distribution and diagnosis. This ability combined with a large field of view and -- compared to existing methods -- excellent detective quantum efficiency represents a revolutionary step for chest and skeletal radiography and will put basic X-ray-work back into the focus of radiological solutions. This paper will explain the basic technology of flat panel detectors, possible system solutions based on this new technology, aspects of the user interface influencing the system utilization and versatility as well as the possibility to redefine the patient examination process for chest and skeletal radiography. Furthermore the author discusses limitations for the first released systems, upgrades for the installed base and possible scenarios for the future. e.g. fluoroscopy or angiography application

  10. Image quality of a Konica Regius 336 digital system in chest radiography

    International Nuclear Information System (INIS)

    Ostinelli, A.; Frigerio, M.; Monti, A.F.; Gelosa, S.; Tognoli, P.; Perniola, N.; Gozzi, G.

    2000-01-01

    Digital radiographic systems permit to optimize execution, depiction and storage of radiological images. Since a Regius 336 digital system (Konica Corp. Tokyo, Japan) devoted to chest radiography Department of S. Anna Hospital in Como, Italy, it was investigated its performance relative to image quality. Konica Regius 336 is a computed radiography system made of a phosphorescence detector plate which is scanned with an infrared semiconductor laser beam. The radiographic image obtained from the detector is subjected to image processing, which allows a stable output and the nonlinear curve typical of conventional radiographic systems. Image quality was assessed based on the following parameters: dose, contrast, noise and spatial resolution. As reference, it was assessed the same parameters on a Cronex 88 analogic chest-changer (DuPont Pharma, North Billerica, Mass, USA). The Regius 336 air kerma values were always higher than the analogic ones (about 10%), both with and without a chest phantom; noise was also greater than in analogic images, sometimes even doubled. The optical densities of a step wedge and the spatial resolution of the digital chest-changer are independent of the X-ray tube voltage consequent to broader optical latitude. Inversely, the analogic images of the wedges show great optical density variability as a function of the X-ray tube voltage (in a range of 2). The modulation transfer functions of the two systems have the same trend. The performance of the Konica Regius 336 is nearly equivalent to that of an analogic system. The main advantages of the digital system are a standard output, lower consumption of radiographic films, higher productiveness and better image quality standard level [it

  11. Digital vs conventional radiography: cost and revenue analysis

    International Nuclear Information System (INIS)

    Dalla Palma, L.; Cuttin, R.; Rimondini, A.; Grisi, G.

    1999-01-01

    The objective of this study was to analyse and compare the operating and investment costs of two radiographic systems, a conventional and a digital one, and to evaluate the cost/revenue ratio of the two systems. The radiological activity over 1 year for chest and skeletal exams was evaluated: 13,401 chest and 7,124 skeletal exams were considered. The following parameters of variable costs were evaluated: the difference between variable proportional costs of the two technologies, the effective variable cost of any size film, including the chemicals, and for different sizes of digital film, variable costs of chest plus skeletal exams performed with the two techniques. Afterwards the economical effect was considered taking into account depreciation during a time of utilization ranging between 8 and 4 years. In the second part of the analysis the total cost and the revenues of the two technologies were determined. The comparison between the digital and conventional systems has shown the following aspects: 1. Digital radiography system has a much higher investment cost in comparison with the conventional one. 2. Operating costs of digital equipment are higher or lower depending on the film size used. Evaluating chest X-ray we reach a breakeven point after 1 year and 10,000 exams only if displayed over 8 x 10-in. film and after 30,000 if displayed over a 11 x 14-in. film. 3. The total cost (variable cost, technology cost, labour cost) of digital technology is lower than that of the conventional system by 20 % on average using 8 x 10-in. film size. 4. Digital technology also allows lesser film waste and lesser film per exam (orig.)

  12. Quality control measurements for digital x-ray detectors

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, N W [Department of Radiology, University Hospitals Leuven, 49 Herenstraat, 3000 Leuven (Belgium); Mackenzie, A [National Co-ordinating Centre for the Physics of Mammography, Medical Physics, Level B, St Luke' s Wing, The Royal Surrey County Hospital NHS Trust, Egerton Road, Guildford, GU2 7XX (United Kingdom); Honey, I D, E-mail: nicholas.marshall@uz.kuleuven.ac.be [Department of Medical Physics, Floor 3, Henriette Raphael House, Guy' s and St Thomas' Hospital, London, SE1 9RT (United Kingdom)

    2011-02-21

    This paper describes a digital radiography (DR) quality control protocol for DR detectors from the forthcoming report from the Institute of Physics and Engineering in Medicine (IPEM). The protocol was applied to a group of six identical caesium iodide (CsI) digital x-ray detectors to assess reproducibility of methods, while four further detectors were assessed to examine the wider applicability. Twelve images with minimal spatial frequency processing are required, from which the detector response, lag, modulation transfer function (MTF), normalized noise power spectrum (NNPS) and threshold contrast-detail (c-d) detectability are calculated. The x-ray spectrum used was 70 kV and 1 mm added copper filtration, with a target detector air kerma of 2.5 {mu}Gy for the NNPS and c-d results. In order to compare detector performance with previous imaging technology, c-d data from four screen/film systems were also acquired, at a target optical density of 1.5 and an average detector air kerma of 2.56 {mu}Gy. The DR detector images were typically acquired in 20 min, with a further 45 min required for image transfer and analysis. The average spatial frequency for the 50% point of the MTF for six identical detectors was 1.29 mm{sup -1} {+-} 0.05 (3.9% coefficient of variation (cov)). The air kerma set for the six systems was 2.57 {mu}Gy {+-} 0.13 (5.0% cov) and the NNPS at this air kerma was 1.42 x 10{sup -5} mm{sup 2} (6.5% cov). The detective quantum efficiency (DQE) measured for the six identical detectors was 0.60 at 0.5 mm{sup -1}, with a maximum cov of 10% at 2.9 mm{sup -1}, while the average DQE was 0.56 at 0.5 mm{sup -1} for three CsI detectors from three different manufacturers. Comparable c-d performance was found for these detectors (5.9% cov) with an average threshold contrast of 0.46% for 11 mm circular discs. The average threshold contrast for the S/F systems was 0.70% at 11 mm, indicating superior imaging performance for the digital systems. The protocol was found

  13. Digital portal radiography in mantle-field irradiation

    International Nuclear Information System (INIS)

    Scheck, R.J.; Wendt, T.; Panzer, M.

    1991-01-01

    This paper evaluates the potential of digital luminescence radiography to improve image quality of portal films in mantle-field irradiation. Conventional and digital verification films of an anthropomorphic phantom and 20 patients treated for Hodgkin disease with mantle radiation therapy were obtained with high-energy photon beams. Both conventional films and storage phosphor screens were placed into a cassette with steel intensifier screens. Exposed storage phosphor screens were processed in a semiautomatic mode, with an optimized contrast curve with moderate edge enhancement, and printed as hard copies in a double-image output format. Images were evaluated according to contrast resolution, delineation of anatomic structures, and accuracy of field alignment. Digital portal radiographs were superior to conventional ones with regard to contrast resolution. Thus, they allowed quick and easy detection of relevant structures, although delineation of anatomic structures and field alignments were judged to be equivalent with both techniques. Shorter exposure times for digital images resulted in a reduction in motion artifacts

  14. Alpha particle radiography and the track plastic detector CR-39

    International Nuclear Information System (INIS)

    Souza, Bismarck Amilar de.

    1991-05-01

    This work develops the radiographic technique using charged particle beams. This technique complements the X-ray conventional radiography, and presents some advantages in certain cases. The material used as nuclear plastic detector was CR-39, manufactured by Pershre Mould. England, of 250 and 1000 μm nominal thicknesses. The irradiations were made with 7 MeV/Nucleon alpha particles beams, accelerated in the CV-28 Cyclotron of Instituto de Engenharia Nuclear/CNEN - Rio de Janeiro. The etch conditions used were a Na OH 6,25 N solution at 70 0 C, varying the etch time, so that the best etch time was found to be six hours. The calibration curve is presented, which permits images interpretation, showed in terms of light transmittance (obtained using a micro densitometer), and in terms of energy losses suffered by alpha particles in several aluminum degradating thicknesses. This curve was checked by the use of other degradating materials: Mylar, Makrofol, and CR-39 itself. The influence of alpha particle beam FWHM widening on images quality, when it crosses several degradating materials, is also presented. Radiographs of some specimen are presented, including some images obtained varying some irradiation and etch parameters. (author). 62 refs., 22 figs., 19 tabs

  15. Problems associated with digital luminescence radiography in the neonate and young infant

    International Nuclear Information System (INIS)

    Arthur, R.J.; Pease, J.N.

    1992-01-01

    An evaluation of the Siemens Digiscan has been undertaken to determine whether digital luminescence radiography (DLR) could replace conventional radiography in the examination of the neonate and young infant. Whilst the overall image quality of the digital radiograph was consistently higher than for conventional radiography the difference was less marked than we had expected. Furthermore, the potential for reduction in radiation dose by reducing the repeat rate due to incorrect exposure was limited. The potential advantages of DLR have been critically examined in relationship to neonatal radiography and a number of problems encountered during the evaluation have been highlighted. (orig.)

  16. Radiography

    Science.gov (United States)

    Gardner, C. G.

    1973-01-01

    Radiography is discussed as a method for nondestructive evaluation of internal flaws of solids. Gamma ray and X-ray equipment are described along with radiographic film, radiograph interpretation, and neutron radiography.

  17. Skin entrance dose for digital and film radiography in Korean dental schools

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Eun Sang; Choi, Kun Ho; Kim, Min Gyu; Lim, Hoi Jeong; Yoon, Suk Ja; Kang, Byung Cheol [Chonnam National University College of Medicine, Gwangju (Korea, Republic of)

    2005-12-15

    This study was aimed to compare skin entrance dose of digital radiography with that of film radiography and to show the dose reduction achievement with digital systems at 11 dental schools in Korea. Forty six intraoral radiographic systems in 11 dental schools were included in this study. Digital sensors were used in 33 systems and film was used in 13 systems. Researchers and the volunteer visited 11 dental schools in Korea. Researchers asked the radiologic technician at each school to set the exposure parameters and aiming the x-ray tube for the peri apical view of the mandibular molar of the volunteer. The skin entrance doses were measured at the same exposure parameters and distance by the technician for each system with a dosimeter (Multi-O-Meter; Unifors instruments, Billdal, Sweden). The median dose was 491.2 {mu}Gy for digital radiography and 1,205.0 {mu}Gy for film radiography. The skin entrance dose in digital radiography was significantly lower than that of film radiography (p<0.05). Fifty-nine percent skin entrance dose reduction with digital peri apical radiography was achieved over the film radiography in Korean dental schools.

  18. Skin entrance dose for digital and film radiography in Korean dental schools

    International Nuclear Information System (INIS)

    Cho, Eun Sang; Choi, Kun Ho; Kim, Min Gyu; Lim, Hoi Jeong; Yoon, Suk Ja; Kang, Byung Cheol

    2005-01-01

    This study was aimed to compare skin entrance dose of digital radiography with that of film radiography and to show the dose reduction achievement with digital systems at 11 dental schools in Korea. Forty six intraoral radiographic systems in 11 dental schools were included in this study. Digital sensors were used in 33 systems and film was used in 13 systems. Researchers and the volunteer visited 11 dental schools in Korea. Researchers asked the radiologic technician at each school to set the exposure parameters and aiming the x-ray tube for the peri apical view of the mandibular molar of the volunteer. The skin entrance doses were measured at the same exposure parameters and distance by the technician for each system with a dosimeter (Multi-O-Meter; Unifors instruments, Billdal, Sweden). The median dose was 491.2 μGy for digital radiography and 1,205.0 μGy for film radiography. The skin entrance dose in digital radiography was significantly lower than that of film radiography (p<0.05). Fifty-nine percent skin entrance dose reduction with digital peri apical radiography was achieved over the film radiography in Korean dental schools.

  19. Digital radiography: are the manufacturers' settings too high? Optimisation of the Kodak digital radiography system with aid of the computed radiography dose index

    International Nuclear Information System (INIS)

    Peters, Sinead E.; Brennan, Patrick C.

    2002-01-01

    Manufacturers offer exposure indices as a safeguard against overexposure in computed radiography, but the basis for recommended values is unclear. This study establishes an optimum exposure index to be used as a guideline for a specific CR system to minimise radiation exposures for computed mobile chest radiography, and compares this with manufacturer guidelines and current practice. An anthropomorphic phantom was employed to establish the minimum milliamperes consistent with acceptable image quality for mobile chest radiography images. This was found to be 2 mAs. Consecutively, 10 patients were exposed with this optimised milliampere value and 10 patients were exposed with the 3.2 mAs routinely used in the department of the study. Image quality was objectively assessed using anatomical criteria. Retrospective analyses of 717 exposure indices recorded over 2 months from mobile chest examinations were performed. The optimised milliampere value provided a significant reduction of the average exposure index from 1840 to 1570 (p<0.0001). This new ''optimum'' exposure index is substantially lower than manufacturer guidelines of 2000 and significantly lower than exposure indices from the retrospective study (1890). Retrospective data showed a significant increase in exposure indices if the examination was performed out of hours. The data provided by this study emphasise the need for clinicians and personnel to consider establishing their own optimum exposure indices for digital investigations rather than simply accepting manufacturers' guidelines. Such an approach, along with regular monitoring of indices, may result in a substantial reduction in patient exposure. (orig.)

  20. Motion subtraction of the larynx using digital radiography

    International Nuclear Information System (INIS)

    Kumakawa, Kohzoh; Miyakawa, Kouichi

    1990-01-01

    The development of digital radiography (DR) has made it possible to analyze the contour of the laryngeal soft tissue structures in more detail than the conventional screen-film method. The authors first used the DR system for time subtraction of the larynx during inspiration and phonation. The images are acquired by means of frontal tomography of the larynx using the imaging plate during inspiration and phonation separately, and stored into the memory of the DR system. The thickness of the slices is 5.0 mm. Time subtraction between the mask image during inspiration and the live image during phonation is performed using digital processing on CRT. Superimposing the two images at the upper trachea and the thyroid cartilage of the same depth, makes it possible to measure movement of the vocal cord and false vocal cord quantitatively in three dimensions. The authors named this time subtraction as motion subtraction of the larynx. This motion subtraction image can be obtained by on-line digital processing without complicated development technique, but has so high spatial resolution. This image processing seems to be useful in functional radiographic analysis of laryngeal diseases. (author)

  1. Digitization errors using digital charge division positionsensitive detectors

    International Nuclear Information System (INIS)

    Berliner, R.; Mildner, D.F.R.; Pringle, O.A.

    1981-01-01

    The data acquisition speed and electronic stability of a charge division position-sensitive detector may be improved by using digital signal processing with a table look-up high speed multiply to form the charge division quotient. This digitization process introduces a positional quantization difficulty which reduces the detector position sensitivity. The degree of the digitization error is dependent on the pulse height spectrum of the detector and on the resolution or dynamic range of the system analog-to-digital converters. The effects have been investigated analytically and by computer simulation. The optimum algorithm for position sensing determination using 8-bit digitization and arithmetic has a digitization error of less than 1%. (orig.)

  2. Real-time radiography, digital radiography, and computed tomography for nonintrusive waste drum characterization

    International Nuclear Information System (INIS)

    Martz, H.E.; Schneberk, D.J.; Roberson, G.P.

    1994-07-01

    We are investigating and developing the application of x-ray nondestructive evaluation (NDE) and gamma-ray nondestructive assay (NDA) methods to nonintrusively characterize 208-liter (55-gallon) mixed waste drums. Mixed wastes contain both hazardous and radioactive materials. We are investigating the use of x-ray NDE methods to verify the content of documented waste drums and determine if they can be used to identify hazardous and nonconforming materials. These NDE methods are also being used to help waste certification and hazardous waste management personnel at LLNL to verify/confirm and/or determine the contents of waste. The gamma-ray NDA method is used to identify the intrinsic radioactive source(s) and to accurately quantify its strength. The NDA method may also be able to identify some hazardous materials such as heavy metals. Also, we are exploring techniques to combine both NDE and NDA data sets to yield the maximum information from these nonintrusive, waste-drum characterization methods. In this paper, we report an our x-ray NDE R ampersand D activities, while our gamma-ray NDA activities are reported elsewhere in the proceedings. We have developed a data, acquisition scanner for x-ray NDE real-time radiography (RTR), as well as digital radiography transmission computed tomography (TCT) along with associated computational techniques for image reconstruction, analysis, and display. We are using this scanner and real-waste drums at Lawrence Livermore National Laboratory (LLNL). In this paper, we discuss some issues associated with x-ray imaging, describe the design construction of an inexpensive NDE drum scanner, provide representative DR and TCT results of both mock- and real-waste drums, and end with a summary of our efforts and future directions. The results of these scans reveal that RTR, DR, and CT imaging techniques can be used in concert to provide valuable information about the interior of low-level-, transuranic-, and mock-waste drums without

  3. Comparison of radiation dose, workflow, patient comfort and financial break-even of standard digital radiography and a novel biplanar low-dose X-ray system for upright full-length lower limb and whole spine radiography

    International Nuclear Information System (INIS)

    Dietrich, Tobias J.; Pfirrmann, Christian W.A.; Pankalla, Katja; Buck, Florian M.; Schwab, Alexander

    2013-01-01

    To compare the radiation dose, workflow, patient comfort, and financial break-even of a standard digital radiography and a biplanar low-dose X-ray system. A standard digital radiography system (Ysio, Siemens Healthcare, Erlangen, Germany) was compared with a biplanar X-ray unit (EOS, EOS imaging, Paris, France) consisting of two X-ray tubes and slot-scanning detectors, arranged at an angle of 90 allowing simultaneous vertical biplanar linear scanning in the upright patient position. We compared data of standing full-length lower limb radiographs and whole spine radiographs of both X-ray systems. Dose-area product was significantly lower for radiographs of the biplanar X-ray system than for the standard digital radiography system (e.g. whole spine radiographs; standard digital radiography system: 392.2 ± 231.7 cGy*cm 2 versus biplanar X-ray system: 158.4 ± 103.8 cGy*cm 2 ). The mean examination time was significantly shorter for biplanar radiographs compared with standard digital radiographs (e.g. whole spine radiographs: 449 s vs 248 s). Patients' comfort regarding noise was significantly higher for the standard digital radiography system. The financial break-even point was 2,602 radiographs/year for the standard digital radiography system compared with 4,077 radiographs/year for the biplanar X-ray unit. The biplanar X-ray unit reduces radiation exposure and increases subjective noise exposure to patients. The biplanar X-ray unit demands a higher number of examinations per year for the financial break-even point, despite the lower labour cost per examination due to the shorter examination time. (orig.)

  4. Selenium-based digital radiography of the cervical spine. Comparison with screen-film radiography for the depiction of anatomic details

    International Nuclear Information System (INIS)

    Ludwig, K.; Diederich, S.; Wormanns, D.; Link, T.M.; Lenzen, H.; Heindel, W.

    2002-01-01

    Purpose: To compare selenium-based digital radiography with conventional screen-film radiography of the cervical spine. Materials and Methods: In a prospective study X-ray images of the cervical spine were obtained in 25 patients using selenium-based digital radiography and conventional screen-film radiography. All images were clinically indicated. Selenium-based digital radiography and conventional screen-film radiography were used in a randomized order. Four radiologists independently evaluated all 50 examinations for the visibility of 76 anatomic details according to a five-level confidence scale (1=not visible, 5=very good visibility). From the evaluation of these anatomic details scores for the upper and middle cervical spine, the cervicothoracic junction and the cervical soft tissues were calculated. The scores for selenium-based digital radiography and conventional screen-film radiography were compared using Wilcoxon's signed rank test. Results: From a total of 15,200 observations (608 per patient) the following scores were calculated for selenium-based digital radiography and for screen-film radiography, respectively: Upper cervical spine 3.88 and 3.94; middle cervical spine 4.60 and 4.48; cervico-thoracic junction 3.64 and 2.62; cervical soft tissue 4.47 and 3.46. The differences between the last two scores were statistically significant (p [de

  5. Value of digital radiography in expiration in detection of pneumothorax

    International Nuclear Information System (INIS)

    Thomsen, L.; Natho, O.; Feigen, U.; Kivelitz, D.; Schulz, U.

    2014-01-01

    Purpose: The purpose of this study was to find out whether pneumothorax detection and exclusion is superior in expiratory digital chest radiography. Materials and Methods: 131 patients with pneumothorax with paired inspiratory and expiratory chest radiographs were analyzed regarding localization and size of pneumothorax. Sensitivity, specificity, negative (npv) and positive predictive value (ppv) as well as the positive (LR+) and negative likelihood ratio (LR-) were determined in a blinded randomized interobserver study with 116 patients. The evaluation was performed by three board-certified radiologists. Results: In 131 patients, there were 139 pneumothoraces, 135 (97.1 %) were located apical, 88 (63.3 %) lateral and 33 (23.7 %) basal. Sensitivity was 99 % for inspiratory and 97 % for expiratory radiographs. The interobserver study yielded a mean sensitivity of 86.1 %/86.1 %, specificity of 97.3 %/93.4 %, npv of 88.7 %/88.5 % and ppv of 96.7 %/92.1 % for inspiration/expiration. For inspiratory radiographs the LR+/LR- were 40.2/0.14 and for expiration 13.9 and 0.15. McNemar-Test showed no significant difference for the detection of pneumothoraces in in-/exspiration. Conclusion: Inspiratory and expiratory digital radiographs are equally suitable for pneumothorax detection. Inspiratory radiographs are recommended as the initial examination of choice for pneumothorax detection, an additional expiratory radiograph is only recommended in doubtful cases. (orig.)

  6. A conceptual optimisation strategy for radiography in a digital environment

    International Nuclear Information System (INIS)

    Baath, M.; Haakansson, M.; Hansson, J.; Maansson, L. G.

    2005-01-01

    Using a completely digital environment for the entire imaging process leads to new possibilities for optimisation of radiography since many restrictions of screen/film systems, such as the small dynamic range and the lack of possibilities for image processing, do not apply any longer. However, at the same time these new possibilities lead to a more complicated optimisation process, since more freedom is given to alter parameters. This paper focuses on describing an optimisation strategy that concentrates on taking advantage of the conceptual differences between digital systems and screen/film systems. The strategy can be summarised as: (a) always include the anatomical background during the optimisation, (b) perform all comparisons at a constant effective dose and (c) separate the image display stage from the image collection stage. A three-step process is proposed where the optimal setting of the technique parameters is determined at first, followed by an optimisation of the image processing. In the final step the optimal dose level - given the optimal settings of the image collection and image display stages - is determined. (authors)

  7. Comparison of scatter rejection and low-contrast performance of scan equalization digital radiography (SEDR), slot-scan digital radiography, and full-field digital radiography systems for chest phantom imaging

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xinming; Shaw, Chris C.; Lai, Chao-Jen; Wang Tianpeng [Department of Imaging Physics, Digital Imaging Research Laboratory, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030-4009 (United States)

    2011-01-15

    Purpose: To investigate and compare the scatter rejection properties and low-contrast performance of the scan equalization digital radiography (SEDR) technique to the slot-scan and conventional full-field digital radiography techniques for chest imaging. Methods: A prototype SEDR system was designed and constructed with an a-Se flat-panel (FP) detector to improve image quality in heavily attenuating regions of an anthropomorphic chest phantom. Slot-scanning geometry was used to reject scattered radiation without attenuating primary x rays. The readout scheme of the FP was modified to erase accumulated scatter signals prior to image readout. A 24-segment beam width modulator was developed to regulate x-ray exposures regionally and compensate for the low x-ray flux in heavily attenuating regions. To measure the scatter-to-primary ratios (SPRs), a 2 mm thick lead plate with a 2-D array of aperture holes was used to measure the primary signals, which were then subtracted from those obtained without the lead plate to determine scatter components. A 2-D array of aluminum beads (3 mm in diameter) was used as the low-contrast objects to measure the contrast ratios (CRs) and contrast-to-noise ratios (CNRs) for evaluating the low-contrast performance in chest phantom images. A set of two images acquired with the same techniques were subtracted from each other to measure the noise levels. SPRs, CRs, and CNRs of the SEDR images were measured in four anatomical regions of chest phantom images and compared to those of slot-scan images and full-field images acquired with and without antiscatter grid. Results: The percentage reduction of SPR (percentage of SPRs reduced with scatter removal/rejection methods relative to that for nongrid full-field imaging) averaged over four anatomical regions was measured to be 80%, 83%, and 71% for SEDR, slot-scan, and full-field with grid, respectively. The average CR over four regions was found to improve over that for nongrid full

  8. Comparison of scatter rejection and low-contrast performance of scan equalization digital radiography (SEDR), slot-scan digital radiography, and full-field digital radiography systems for chest phantom imaging

    International Nuclear Information System (INIS)

    Liu Xinming; Shaw, Chris C.; Lai, Chao-Jen; Wang Tianpeng

    2011-01-01

    Purpose: To investigate and compare the scatter rejection properties and low-contrast performance of the scan equalization digital radiography (SEDR) technique to the slot-scan and conventional full-field digital radiography techniques for chest imaging. Methods: A prototype SEDR system was designed and constructed with an a-Se flat-panel (FP) detector to improve image quality in heavily attenuating regions of an anthropomorphic chest phantom. Slot-scanning geometry was used to reject scattered radiation without attenuating primary x rays. The readout scheme of the FP was modified to erase accumulated scatter signals prior to image readout. A 24-segment beam width modulator was developed to regulate x-ray exposures regionally and compensate for the low x-ray flux in heavily attenuating regions. To measure the scatter-to-primary ratios (SPRs), a 2 mm thick lead plate with a 2-D array of aperture holes was used to measure the primary signals, which were then subtracted from those obtained without the lead plate to determine scatter components. A 2-D array of aluminum beads (3 mm in diameter) was used as the low-contrast objects to measure the contrast ratios (CRs) and contrast-to-noise ratios (CNRs) for evaluating the low-contrast performance in chest phantom images. A set of two images acquired with the same techniques were subtracted from each other to measure the noise levels. SPRs, CRs, and CNRs of the SEDR images were measured in four anatomical regions of chest phantom images and compared to those of slot-scan images and full-field images acquired with and without antiscatter grid. Results: The percentage reduction of SPR (percentage of SPRs reduced with scatter removal/rejection methods relative to that for nongrid full-field imaging) averaged over four anatomical regions was measured to be 80%, 83%, and 71% for SEDR, slot-scan, and full-field with grid, respectively. The average CR over four regions was found to improve over that for nongrid full

  9. Performance Characteristic of a CsI(Tl) Flat Panel Detector Radiography System

    International Nuclear Information System (INIS)

    Jeong, Hoi Woun; Min, Jung Hwan; Kim, Jung Min; Park, Min Seok; Lee, Gaung Young

    2012-01-01

    The purpose of this work was to evaluate an amorphous silicon cesium iodide based indirect flat-panel detector (FPD) in terms of their modulation transfer function (MTF), Wiener spectrum (WS, or noise power spectrum, NPS), and detective quantum efficiency (DQE). Measurements were made on flat-panel detector using the International Electrotechnical Commission (IEC) defined RQA3, RQA5, RQA7, and RQA9 radiographic technique. The MTFs of the systems were measured using an edge method. The WS(NPS) of the systems were determined for a range of exposure levels by two-dimensional (2D). Fourier analysis of uniformly exposed radiographs. The DQEs were assessed from the measured MTF, WS(NPS), exposure, and estimated ideal signal-to-noise ratios. Characteristic curve in the RQA3 showed difference in the characteristic curve from RQA5, RQA7, RQA9. MTFs were not differences according to x-ray beam quality. WS(NPS) was reduced with increasing dose, and RQA 3, RQA5, RQA7, RQA9 as the order is reduced. DQE represented the best in the 1mR, RQA 3, RQA5, RQA7, RQA9 decrease in the order. The physical imaging characteristics of FPD may also differ from input beam quality. This study gives an initial motivation that the physical imaging characteristics of FPD is an important issue for the right use of digital radiography system.

  10. Performance Characteristic of a CsI(Tl) Flat Panel Detector Radiography System

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hoi Woun [Dept. of Radiological Science, Baekseok Culture University, Seoul (Korea, Republic of); Min, Jung Hwan [Dept. of Radiological Technology, Shingu University, Seongnam (Korea, Republic of); Kim, Jung Min [Dept. of Radiological Science, Korea University, Health Science College, Seoul (Korea, Republic of); Park, Min Seok [Korea Institue of Radiological and Medical Sicences, Research Institute of Radiologycal and Medical Sciences, Seoul (Korea, Republic of); Lee, Gaung Young [National Institute of Food and Drug Safety Evaluation, Seoul (Korea, Republic of)

    2012-06-15

    The purpose of this work was to evaluate an amorphous silicon cesium iodide based indirect flat-panel detector (FPD) in terms of their modulation transfer function (MTF), Wiener spectrum (WS, or noise power spectrum, NPS), and detective quantum efficiency (DQE). Measurements were made on flat-panel detector using the International Electrotechnical Commission (IEC) defined RQA3, RQA5, RQA7, and RQA9 radiographic technique. The MTFs of the systems were measured using an edge method. The WS(NPS) of the systems were determined for a range of exposure levels by two-dimensional (2D). Fourier analysis of uniformly exposed radiographs. The DQEs were assessed from the measured MTF, WS(NPS), exposure, and estimated ideal signal-to-noise ratios. Characteristic curve in the RQA3 showed difference in the characteristic curve from RQA5, RQA7, RQA9. MTFs were not differences according to x-ray beam quality. WS(NPS) was reduced with increasing dose, and RQA 3, RQA5, RQA7, RQA9 as the order is reduced. DQE represented the best in the 1mR, RQA 3, RQA5, RQA7, RQA9 decrease in the order. The physical imaging characteristics of FPD may also differ from input beam quality. This study gives an initial motivation that the physical imaging characteristics of FPD is an important issue for the right use of digital radiography system.

  11. Study of a new scatter rejection technique in digital radiography

    International Nuclear Information System (INIS)

    Bottari, S.; Ciocci, M.A.; Fortunato, M.; Maestro, P.; Malakhov, N.; Marrocchesi, P.S.; Meucci, M.; Millucci, V.; Paoletti, R.; Scribano, A.; Turini, N.

    2001-01-01

    A new technique for digital mammography based on the use of a collimator and an anti-scatter grid coupled with a mosaic detector has been studied with a Monte Carlo program. The simulation, with a low-energy spectrum X-ray beam and a breast phantom, provides a quantitative assessment of the capability of the method to reduce the physical background of the image due to scattering in the body, without introducing image artifacts. With minor modifications to the existing X-ray facilities, the method could also be applied to area detectors. To verify the results of the simulation, an experimental setup based on a CCD camera coupled via a fiber optic plate to a CsI(Tl) scintillator is under test

  12. Study of a new scatter rejection technique in digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Bottari, S.; Ciocci, M.A. E-mail: ciocci@pi.infn.it; Fortunato, M.; Maestro, P.; Malakhov, N.; Marrocchesi, P.S.; Meucci, M.; Millucci, V.; Paoletti, R.; Scribano, A.; Turini, N

    2001-04-01

    A new technique for digital mammography based on the use of a collimator and an anti-scatter grid coupled with a mosaic detector has been studied with a Monte Carlo program. The simulation, with a low-energy spectrum X-ray beam and a breast phantom, provides a quantitative assessment of the capability of the method to reduce the physical background of the image due to scattering in the body, without introducing image artifacts. With minor modifications to the existing X-ray facilities, the method could also be applied to area detectors. To verify the results of the simulation, an experimental setup based on a CCD camera coupled via a fiber optic plate to a CsI(Tl) scintillator is under test.

  13. Role of digital tomosynthesis and dual energy subtraction digital radiography in detecting pulmonary nodules

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sarvana G. [Department of Radiodiagnosis and Imaging, Postgraduate Institute of Medical Education and Research (PGIMER), Sector 12, Chandigarh 160012 (India); Garg, Mandeep Kumar, E-mail: gargmandeep01@gmail.com [Department of Radiodiagnosis and Imaging, Postgraduate Institute of Medical Education and Research (PGIMER), Sector 12, Chandigarh 160012 (India); Khandelwal, Niranjan; Gupta, Pankaj [Department of Radiodiagnosis and Imaging, Postgraduate Institute of Medical Education and Research (PGIMER), Sector 12, Chandigarh 160012 (India); Gupta, Dheeraj; Aggarwal, Ashutosh Nath [Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Sector 12, Chandigarh 160012 (India); Bansal, Subash Chand [Department of Radiodiagnosis and Imaging, Postgraduate Institute of Medical Education and Research (PGIMER), Sector 12, Chandigarh 160012 (India)

    2015-07-15

    Highlights: • Accuracy of digital tomosynthesis for nodule detection is substantially higher. • Improvement in diagnostic accuracy is most pronounced for nodules <10 mm. • There is five times increase in radiation dose compared to DR. - Abstract: Objective: Digital tomosynthesis (DT) and dual-energy subtraction digital radiography (DES-DR) are known to perform better than conventional radiography in the detection of pulmonary nodules. Yet the comparative diagnostic performances of DT, DES-DR and digital radiography (DR) is not known. The present study compares the diagnostic performances of DT, DES-DR and DR in detecting pulmonary nodules. Subjects and methods: The institutional Review Board approved the study and informed written consent was obtained. Fifty-five patients (30 with pulmonary nodules, 25 with non-nodular focal chest pathology) were included in the study. DT and DES-DR were performed within14 days of MDCT. Composite images acquired at high kVp as part of DES-DR were used as DR images. Images were analyzed for presence of nodules and calcification in nodules. Interpretations were assigned confidence levels from 1 to 5 according to Five-Point rating scale. Areas under the receiver operating characteristic curves were compared using Z test. Results: A total of 110 (88 non-calcified, 22 calcified) nodules were identified on MDCT. For detection of nodules, DR showed cumulative sensitivity and specificity of 25.45% and 67.97%, respectively. DT showed a cumulative sensitivity and specificity of 60.9% and 85.07%, respectively. The performance was significantly better than DR (p < 0.003). DES-DR showed sensitivity and specificity of 27.75% and 82.64%, not statistically different from those of DR (p—0.92). In detection of calcification, there was no statistically significant difference between DT, DES-DR and DR. Conclusions: DT performs significantly better than DES-DR and DR at the cost of moderate increase in radiation dose.

  14. Effective dose efficiency: an application-specific metric of quality and dose for digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Samei, Ehsan; Ranger, Nicole T; Dobbins, James T III; Ravin, Carl E, E-mail: samei@duke.edu [Carl E Ravin Advanced Imaging Laboratories, Department of Radiology (United States)

    2011-08-21

    The detective quantum efficiency (DQE) and the effective DQE (eDQE) are relevant metrics of image quality for digital radiography detectors and systems, respectively. The current study further extends the eDQE methodology to technique optimization using a new metric of the effective dose efficiency (eDE), reflecting both the image quality as well as the effective dose (ED) attributes of the imaging system. Using phantoms representing pediatric, adult and large adult body habitus, image quality measurements were made at 80, 100, 120 and 140 kVp using the standard eDQE protocol and exposures. ED was computed using Monte Carlo methods. The eDE was then computed as a ratio of image quality to ED for each of the phantom/spectral conditions. The eDQE and eDE results showed the same trends across tube potential with 80 kVp yielding the highest values and 120 kVp yielding the lowest. The eDE results for the pediatric phantom were markedly lower than the results for the adult phantom at spatial frequencies lower than 1.2-1.7 mm{sup -1}, primarily due to a correspondingly higher value of ED per entrance exposure. The relative performance for the adult and large adult phantoms was generally comparable but affected by kVps. The eDE results for the large adult configuration were lower than the eDE results for the adult phantom, across all spatial frequencies (120 and 140 kVp) and at spatial frequencies greater than 1.0 mm{sup -1} (80 and 100 kVp). Demonstrated for chest radiography, the eDE shows promise as an application-specific metric of imaging performance, reflective of body habitus and radiographic technique, with utility for radiography protocol assessment and optimization.

  15. Digital teaching library (DTL) development for radiography education

    International Nuclear Information System (INIS)

    Cosson, Philip; Willis, Neil

    2012-01-01

    Purpose: Having access to a library of radiological images in the university setting is important for teaching and learning in diagnostic radiography. Modern modalities such as PETCT create data volumes rather than single static 2D images. A PACS repository of images alone does not constitute a teaching library without some text based searchable index. A review of several options for acquiring a digital teaching library (DTL) of such indexed DICOM data is presented. Discussion: The data protection principles, current guidance and potential methods for migrating and cleansing large quantities of DICOM data from a clinical PACS prior to transfer to a university setting is discussed. The chosen method is described and the important enabling technology identified. Various methods of index construction are outlined and a method of migrating and cleansing HL7 data from a clinical RIS described. Results: Three terabytes of de-normalised DICOM image files were cleansed of patient, staff and geographic identifiers, within the header tags and pixel data. These files were then migrated to an educational PACS hosted at a university. A searchable index database was created based on 90,200 reports and associated data, and 886,263 DICOM headers to enable meaningful results to be found from the 51,304 unique patient specific cases. Conclusion: A large DTL in the university setting using PACS technology is becoming a valuable resource for teaching, learning and assessment.

  16. Investigation on radiation doses to patients in digital radiography

    International Nuclear Information System (INIS)

    Qiu Zhengshuai; Deng Daping; Li Quantai; Song Gang; Su Xu

    2014-01-01

    Objective: To investigate the patients' radiation dose received in digital radiography(DR) and provide basic data for developing diagnostic reference levels. Methods: The patient's ESD was estimated using the TLDs and DAP was measured by the dose-area product meter. The E values were then calculated by the DAP using Monte Carlo data and RefDose software. Measurements were made for twelve types of examination: skull PA, skull LAT, chest PA, chest LAT, abdomen AP, pelvis AP, cervix spine PA, cervix spine LAT, thoracic spine PA, thoracic spine LAT, lumber spine PA and lumber spine LAT. Results: Both kV and mAs varied in the same type of examination for ESD, DAP and E(F = 33.47, 24.68, 43.19, P < 0.05). The dose each time for lumber spine LAT was the highest, reached 4.62 mGy in ESD and 2.26 Gy·cm 2 in DAP, respectively. The E of abdomen AP averaged as 0.59 mSv, higher than that of lumber spine LAT. Even for the same type of examination, the dose from each equipment was different. Conclusions: DR has the potential to reduce the patients' radiation doses. The guidance levels suitable for Chinese population should be established as soon as possible. (authors)

  17. Digital radiography of crush thoracic trauma in the Sichuan earthquake

    Science.gov (United States)

    Dong, Zhi-Hui; Shao, Heng; Chen, Tian-Wu; Chu, Zhi-Gang; Deng, Wen; Tang, Si-Shi; Chen, Jing; Yang, Zhi-Gang

    2011-01-01

    AIM: To investigate the features of crush thoracic trauma in Sichuan earthquake victims using chest digital radiography (CDR). METHODS: We retrospectively reviewed 772 CDR of 417 females and 355 males who had suffered crush thoracic trauma in the Sichuan earthquake. Patient age ranged from 0.5 to 103 years. CDR was performed between May 12, 2008 and June 7, 2008. We looked for injury to the thoracic cage, pulmonary parenchyma and the pleura. RESULTS: Antero-posterior (AP) and lateral CDR were obtained in 349 patients, the remaining 423 patients underwent only AP CDR. Thoracic cage fractures, pulmonary contusion and pleural injuries were noted in 331 (42.9%; 95% CI: 39.4%-46.4%), 67 and 135 patients, respectively. Of the 256 patients with rib fractures, the mean number of fractured ribs per patient was 3. Rib fractures were mostly distributed from the 3rd through to the 8th ribs and the vast majority involved posterior and lateral locations along the rib. Rib fractures had a significant positive association with non-rib thoracic fractures, pulmonary contusion and pleural injuries (P < 0.001). The number of rib fractures and pulmonary contusions were significant factors associated with patient death. CONCLUSION: Earthquake-related crush thoracic trauma has the potential for multiple fractures. The high number of fractured ribs and pulmonary contusions were significant factors which needed appropriate medical treatment. PMID:22132298

  18. A new clinical unit for digital radiography based on a thick amorphous Selenium plate: Physical and psychophysical characterization

    International Nuclear Information System (INIS)

    Rivetti, Stefano; Lanconelli, Nico; Bertolini, Marco; Acchiappati, Domenico

    2011-01-01

    Purpose: Here, we present a physical and psychophysical characterization of a new clinical unit (named AcSelerate) for digital radiography based on a thick a-Se layer. We also compared images acquired with and without a software filter (named CRF) developed for reducing sharpness and noise of the images and making them similar to images coming from traditional computed radiography systems. Methods: The characterization was achieved in terms of physical figures of merit [modulation transfer function (MTF), noise power spectra (NPS), detective quantum efficiency (DQE)], and psychophysical parameters (contrast-detail analysis with an automatic reading of CDRAD images). We accomplished measurements with four standard beam conditions: RAQ3, RQA5, RQA7, and RQA9. Results: The system shows an excellent MTF (about 50% at the Nyquist frequency). The DQE is about 55% at 0.5 lp/mm and above 20% at the Nyquist frequency and is almost independent from exposure. The contrast-detail curves are comparable to some of the best published data for other systems devoted to imaging in general radiography. The CRF filter influences both the MTF and NPS, but it does lead to very small changes on DQE. Also the visibility of CDRAD details is basically unaltered, when the filter is activated. Conclusions: As normally happens with detector based on direct conversion, the system presents an excellent MTF. The improved efficiency caused by the thick layer allows getting good noise characteristics and DQE results better (about 10% on average) than many of the computed radiography (CR) systems and comparable to those obtained by the best systems for digital radiography available on the market.

  19. Dose audit for patients undergoing two common radiography examinations with digital radiology systems

    Science.gov (United States)

    İnal, Tolga; Ataç, Gökçe

    2014-01-01

    PURPOSE We aimed to determine the radiation doses delivered to patients undergoing general examinations using computed or digital radiography systems in Turkey. MATERIALS AND METHODS Radiographs of 20 patients undergoing posteroanterior chest X-ray and of 20 patients undergoing anteroposterior kidney-ureter-bladder radiography were evaluated in five X-ray rooms at four local hospitals in the Ankara region. Currently, almost all radiology departments in Turkey have switched from conventional radiography systems to computed radiography or digital radiography systems. Patient dose was measured for both systems. The results were compared with published diagnostic reference levels (DRLs) from the European Union and International Atomic Energy Agency. RESULTS The average entrance surface doses (ESDs) for chest examinations exceeded established international DRLs at two of the X-ray rooms in a hospital with computed radiography. All of the other ESD measurements were approximately equal to or below the DRLs for both examinations in all of the remaining hospitals. Improper adjustment of the exposure parameters, uncalibrated automatic exposure control systems, and failure of the technologists to choose exposure parameters properly were problems we noticed during the study. CONCLUSION This study is an initial attempt at establishing local DRL values for digital radiography systems, and will provide a benchmark so that the authorities can establish reference dose levels for diagnostic radiology in Turkey. PMID:24317331

  20. Dose audit for patients undergoing two common radiography examinations with digital radiology systems.

    Science.gov (United States)

    İnal, Tolga; Ataç, Gökçe

    2014-01-01

    We aimed to determine the radiation doses delivered to patients undergoing general examinations using computed or digital radiography systems in Turkey. Radiographs of 20 patients undergoing posteroanterior chest X-ray and of 20 patients undergoing anteroposterior kidney-ureter-bladder radiography were evaluated in five X-ray rooms at four local hospitals in the Ankara region. Currently, almost all radiology departments in Turkey have switched from conventional radiography systems to computed radiography or digital radiography systems. Patient dose was measured for both systems. The results were compared with published diagnostic reference levels (DRLs) from the European Union and International Atomic Energy Agency. The average entrance surface doses (ESDs) for chest examinations exceeded established international DRLs at two of the X-ray rooms in a hospital with computed radiography. All of the other ESD measurements were approximately equal to or below the DRLs for both examinations in all of the remaining hospitals. Improper adjustment of the exposure parameters, uncalibrated automatic exposure control systems, and failure of the technologists to choose exposure parameters properly were problems we noticed during the study. This study is an initial attempt at establishing local DRL values for digital radiography systems, and will provide a benchmark so that the authorities can establish reference dose levels for diagnostic radiology in Turkey.

  1. Reliability of digital panoramic radiography in the diagnosis of carotid artery calcifications

    Directory of Open Access Journals (Sweden)

    Vilson Lacerda Brasileiro Junior

    2014-02-01

    Full Text Available Objective The present study evaluated the reliability of digital panoramic radiography in the diagnosis of carotid artery calcifications. Materials and Methods Thirty-five patients under high-risk for development of carotid artery calcifications who had digital panoramic radiography were referred to undergo ultrasonography. Thus, 70 arteries were assessed by both methods. The main parameters utilized to evaluate the panoramic radiography reliability in the diagnosis of carotid artery calcifications were accuracy, sensitivity, specificity and positive predictive value of this method as compared with ultrasonography. Additionally, the McNemar's test was utilized to verify whether there was a statistically significant difference between digital panoramic radiography and ultrasonography. Results Ultrasonography demonstrated carotid artery calcifications in 17 (48.57% patients. Such individuals presented with a total of 29 (41.43% carotid arteries affected by calcification. Radiography was accurate in 71.43% (n = 50 of cases evaluated. The degree of sensitivity of this method was 37.93%, specificity of 95.12% and positive predictive value of 84.61%. A statistically significant difference (p < 0.001 was observed between the methods evaluated in their capacity to diagnose carotid artery calcifications. Conclusion Digital panoramic radiography should not be indicated as a method of choice in the investigation of carotid artery calcifications.

  2. Multiple-energy tissue-cancellation applications of a digital beam attenuator to chest radiography

    International Nuclear Information System (INIS)

    Dobbins, J.T. III.

    1985-01-01

    The digitally-formed primary beam attenuator (DBA) spatially modulates the x-ray fluence incident upon the patient to selectively attenuate regions of interest. The DBA attenuating mask is constructed from CeO 2 powder by a modified printing technique and uses image information from an initial low-dose exposure. Two tissue-cancellation imaging techniques are investigated with the DBA: (1) energy-dependent information is used to form a beam attenuator that attenuates specific tissues in the primary x-ray beam for tissue-cancelled film radiography; (2) the beam attenuator is used to improve image signal-to-noise and scattered radiation properties in traditional energy-subtraction tissue-cancellation imaging with digital detectors. The tissue-cancellation techniques in the primary x-ray beam were capable of adequately removing either soft-tissue or bone from the final compensated film radiograph when using a phantom with well defined soft-tissue and bone sections. However, when tried on an anthropomorphic chest phantom the results were adequate for cancellation of large soft tissue structures, but unsatisfactory for cancellation of bony structures such as the ribs, because of the limited spatial frequency content of the attenuating mask. The second technique (with digital detectors) showed improved uniformity of image signal-to-noise and a two-fold increase in soft-tissue nodule contrast due to improved scattered radiation properties. The tissue-cancelled images contained residual image contributions from the presence of the attenuating mask, but this residual may be correctable by future algorithms

  3. Fast digitizing and digital signal processing of detector signals

    International Nuclear Information System (INIS)

    Hannaske, Roland

    2008-01-01

    A fast-digitizer data acquisition system recently installed at the neutron time-of-flight experiment nELBE, which is located at the superconducting electron accelerator ELBE of Forschungszentrum Dresden-Rossendorf, is tested with two different detector types. Preamplifier signals from a high-purity germanium detector are digitized, stored and finally processed. For a precise determination of the energy of the detected radiation, the moving-window deconvolution algorithm is used to compensate the ballistic deficit and different shaping algorithms are applied. The energy resolution is determined in an experiment with γ-rays from a 22 Na source and is compared to the energy resolution achieved with analogously processed signals. On the other hand, signals from the photomultipliers of barium fluoride and plastic scintillation detectors are digitized. These signals have risetimes of a few nanoseconds only. The moment of interaction of the radiation with the detector is determined by methods of digital signal processing. Therefore, different timing algorithms are implemented and tested with data from an experiment at nELBE. The time resolutions achieved with these algorithms are compared to each other as well as to reference values coming from analog signal processing. In addition to these experiments, some properties of the digitizing hardware are measured and a program for the analysis of stored, digitized data is developed. The analysis of the signals shows that the energy resolution achieved with the 10-bit digitizer system used here is not competitive to a 14-bit peak-sensing ADC, although the ballistic deficit can be fully corrected. However, digital methods give better result in sub-ns timing than analog signal processing. (orig.)

  4. Structural analysis of jewelry from the Moche tomb of the `lady of Cao' by X-ray digital radiography

    Science.gov (United States)

    Azeredo, S. R.; Cesareo, R.; Franco, R.; Fernandez, A.; Bustamante, A.; Lopes, R. T.

    2018-04-01

    Nose ornaments from the tomb of the `Lady of Cao', a mummified woman representative of the Moche culture and dated to the third-or-fourth century AD, were analyzed by X-ray digital radiography. These spectacular gold and silver jewels are some of the most sophisticated metalworking ever produced in ancient America. The Mochecivilization flourished along the north coast of present-day Peru, between the Andes and the Pacific Ocean, approximately between 100 and 600 AD. The Moche were very sophisticated artisans and metal smiths, being considered the finest producers of jewels and artifacts of the region. A portable X-ray digital radiography (XDR) system consisting of a flat panel detector with high resolution image and a mini X-ray tube was used for the structural analysis of the Moche jewels aiming at inferring different joining methods of the silver-gold sheets. The radiographic analysis showed some differences in the joint of the silver-and-gold sheets. Presence of filler material and adhesive for joining the silver-and-gold sheets was visible as well as silver-gold junctions without filler material (or with a material invisible in radiography). Furthermore, the technique demonstrated the advantage of using a portable XDR micro system when the sample cannot be brought to the laboratory.

  5. Radiography imaging by 64 and 128 micro-strips crystalline detectors at different X-ray energies

    International Nuclear Information System (INIS)

    Leyva, A.; Cabal, A.; Montano, L. M.; Fontaine, M.; Mora, R. de la; Padilla, F.

    2006-01-01

    This paper summarizes some results obtained in the evaluation of the performance of position sensitive detectors in track reconstruction in particle physics experiments. Crystalline silicon micro-strips detectors with 64 and 128 channels and 100 μm pitch were used to obtain radiographic digital images of different objects. The more relevant figures for spectrometry applications were measured and reported. Two-dimensional images were obtained by scanning the object with a collimated beam using different source-target-detector positioning and three sources of X-rays (8.04, 18.55 and 22.16 keV). The counts acquired by each strip correspond to a particular collimator position during the scan, thus serving to reconstruct the image of the exposed to X-ray object and to reveal its internal structure. The use of some techniques for image processing allow the further improvement of the radiography quality. The preliminary results obtained using in-house made and accreditation mammography phantoms allow to infer that such detectors can be successfully introduced in the digital mammography practice. (Author)

  6. Lumbar spine radiography — poor collimation practices after implementation of digital technology

    DEFF Research Database (Denmark)

    Zetterberg, Lars Gøran; Espeland, Ansgar

    2011-01-01

    Objectives: The transition from analogue to digital radiography may have reduced the motivation to perform proper collimation, as digital techniques have made it possible to mask areas irradiated outside the area of diagnostic interest (ADI). We examined the hypothesis that collimation practices...

  7. An examination of automatic exposure control regimes for two digital radiography systems

    International Nuclear Information System (INIS)

    Marshall, N W

    2009-01-01

    The influence of two methods of an automatic exposure control (AEC) setup using a simple measure of detectability is examined as a function of x-ray beam quality for a computed radiography (CR) system and for an indirect conversion digital radiography (DR) system. The regimes assessed were constant air kerma at the detector and the constant contrast noise ratio (CNR). A low scatter geometry was employed with x-ray spectra varying from 60 kV and 1 mm Cu to 125 kV and 2 mm Cu. The CNR was measured using a 2 mm thick Al square of dimension 1 cm by 1 cm. Detectability was quantified via a nominal contrast for a fixed beam quality of 70 kV and 1 mm added Cu filtration, taken from c-d curves measured using the Leeds TO20 test object, for the four x-ray spectra. In addition, objective image quality parameters including modulation transfer function (MTF), noise power spectrum (NPS) and detective quantum efficiency (DQE) were also measured for both systems at the four different x-ray spectra. It was found that the constant air kerma strategy did not maintain threshold nominal contrast (simple detectability) constant as the x-ray beam mean energy increased, for either the CR system or the DR system. For the CR detector, the threshold nominal contrast for a 1 mm disc increased by a factor of 4.4 from 3.50% to 15.4% as the tube potential was raised from 60 kV to 125 kV, while for the DR detector, the threshold nominal contrast increased by a factor of 3.4, from 2.27% to 7.67% as the tube potential increased from 60 kV to 120 kV. The constant CNR method was more successful at maintaining constant detectability for the c-d discs. The threshold nominal contrast for the 1 mm disc changed by a factor of 1.2, from 4.80% to 5.70% for the CR system, as the spectrum changed from 60 kV to 125 kV. For the indirect conversion detector, the threshold nominal contrast increased from 2.27% to 5.66% (a factor of 1.4 increase). The constant CNR strategy required an increase in air kerma by

  8. An examination of automatic exposure control regimes for two digital radiography systems

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, N W [Radiation Safety Section, Clinical Physics CAU, Dominion House, 60, Barts Close, St Bartholomew' s Hospital, EC1A 7BE, London (United Kingdom)], E-mail: nicholas.marshall@uz.kuleuven.ac.be

    2009-08-07

    The influence of two methods of an automatic exposure control (AEC) setup using a simple measure of detectability is examined as a function of x-ray beam quality for a computed radiography (CR) system and for an indirect conversion digital radiography (DR) system. The regimes assessed were constant air kerma at the detector and the constant contrast noise ratio (CNR). A low scatter geometry was employed with x-ray spectra varying from 60 kV and 1 mm Cu to 125 kV and 2 mm Cu. The CNR was measured using a 2 mm thick Al square of dimension 1 cm by 1 cm. Detectability was quantified via a nominal contrast for a fixed beam quality of 70 kV and 1 mm added Cu filtration, taken from c-d curves measured using the Leeds TO20 test object, for the four x-ray spectra. In addition, objective image quality parameters including modulation transfer function (MTF), noise power spectrum (NPS) and detective quantum efficiency (DQE) were also measured for both systems at the four different x-ray spectra. It was found that the constant air kerma strategy did not maintain threshold nominal contrast (simple detectability) constant as the x-ray beam mean energy increased, for either the CR system or the DR system. For the CR detector, the threshold nominal contrast for a 1 mm disc increased by a factor of 4.4 from 3.50% to 15.4% as the tube potential was raised from 60 kV to 125 kV, while for the DR detector, the threshold nominal contrast increased by a factor of 3.4, from 2.27% to 7.67% as the tube potential increased from 60 kV to 120 kV. The constant CNR method was more successful at maintaining constant detectability for the c-d discs. The threshold nominal contrast for the 1 mm disc changed by a factor of 1.2, from 4.80% to 5.70% for the CR system, as the spectrum changed from 60 kV to 125 kV. For the indirect conversion detector, the threshold nominal contrast increased from 2.27% to 5.66% (a factor of 1.4 increase). The constant CNR strategy required an increase in air kerma by

  9. Proton Radiography: Cross Section Measurements and Detector Development

    International Nuclear Information System (INIS)

    Longo, Michael J.

    2003-01-01

    OAK-B135 The physics goal of this project is to measure forward production of neutrons and photons produced by high-energy proton beams striking a variety of targets. This will provide data essential to proton radiography. This work is being carried out in conjunction with the Fermilab Experiment 907 (MIPP) collaboration including physicists from Lawrence Livermore Laboratory. Our group is responsible for the E907 forward neutron/photon calorimeter. The project is on track to meet its technical milestones, though the overall schedule at Fermilab has slipped. The electromagnetic calorimeter and the hadron calorimeter were both assembled and ready for testing with beam in December 2003

  10. Clinical evaluation of a mobile digital specimen radiography system for intraoperative specimen verification.

    Science.gov (United States)

    Wang, Yingbing; Ebuoma, Lilian; Saksena, Mansi; Liu, Bob; Specht, Michelle; Rafferty, Elizabeth

    2014-08-01

    Use of mobile digital specimen radiography systems expedites intraoperative verification of excised breast specimens. The purpose of this study was to evaluate the performance of a such a system for verifying targets. A retrospective review included 100 consecutive pairs of breast specimen radiographs. Specimens were imaged in the operating room with a mobile digital specimen radiography system and then with a conventional digital mammography system in the radiology department. Two expert reviewers independently scored each image for image quality on a 3-point scale and confidence in target visualization on a 5-point scale. A target was considered confidently verified only if both reviewers declared the target to be confidently detected. The 100 specimens contained a total of 174 targets, including 85 clips (49%), 53 calcifications (30%), 35 masses (20%), and one architectural distortion (1%). Although a significantly higher percentage of mobile digital specimen radiographs were considered poor quality by at least one reviewer (25%) compared with conventional digital mammograms (1%), 169 targets (97%), were confidently verified with mobile specimen radiography; 172 targets (98%) were verified with conventional digital mammography. Three faint masses were not confidently verified with mobile specimen radiography, and conventional digital mammography was needed for confirmation. One faint mass and one architectural distortion were not confidently verified with either method. Mobile digital specimen radiography allows high diagnostic confidence for verification of target excision in breast specimens across target types, despite lower image quality. Substituting this modality for conventional digital mammography can eliminate delays associated with specimen transport, potentially decreasing surgical duration and increasing operating room throughput.

  11. Options for radiation dose optimisation in pelvic digital radiography: A phantom study

    International Nuclear Information System (INIS)

    Manning-Stanley, Anthony S.; Ward, Anthony J.; England, Andrew

    2012-01-01

    Purpose: To investigate the effects of phantom orientation and AEC chamber selection on radiation dose and image quality (IQ) for digital radiography (DR) examinations of the pelvis. Methods: A phantom study was conducted using a DR detector, utilising all AEC chamber combinations. Current recommended orientation (Cr-AEC) was with the outer AEC chambers cranially orientated. mAs (given), source-to-skin distance and kV p data facilitated entrance surface dose and effective dose calculations. Six anatomical areas were blindly graded by two observers (3-point scale) for IQ. Statistical differences in radiation dose were determined using the paired Student’s t-test. IQ data was analysed for inter-observer variability (ICC) and statistical differences (Wilcoxon test). Results: Switching phantom orientation (caudally orientated outer AEC chambers: Ca-AEC) reduced mean radiation dose by 36.8%, (p < 0.001). A minor reduction in median IQ (15.5 vs. 15) was seen (p < 0.001). One Ca-AEC orientated image (1.6%) had all anatomical areas graded ‘inadequate’ by at least one observer; all other images were considered ‘adequate’ for all areas. In the Ca-AEC orientation, at least a 44% dose reduction was achievable (p < 0.001) when only the outer AEC chambers were used. In the Cr-AEC orientation, at least 11% dose reduction was achieved (p < 0.001); here the central chamber was used alone, or in combination. IQ scores fell, but remained ‘adequate’. Conclusion: Switching pelvic orientation relative to AEC chamber position can optimise radiation dose during pelvic radiography. AEC chamber position should be clearly marked on equipment to facilitate this. AEC selection should be an active process.

  12. Film replacement by digital x-ray detectors - the correct procedure and equipment

    International Nuclear Information System (INIS)

    Ewert, U.; Zscherpel, U.; Bavendiek, K.

    2004-01-01

    New digital detectors were developed for medical applications, which have the potential to substitute the X-ray film and revolutionise the radiological technique. Digital Detector Arrays (DDA: Flat Panel Detectors, Line Detectors) and Imaging Plates (Computed Radiography) allow a fast detection of radiographic images in a shorter time and with higher dynamic than film applications. Companies report about a reduction of exposure time down to 5 - 25% in comparison to NDT film exposures. This provides together with the reduction of consumables economical (and also ecological) benefits and short amortisation periods. But this does not always provide the same image quality as NDT film. The requirements of the European and USA standards for film radiography are analysed to derive correct requirements for the digital image quality and procedures for prediction and measurement of image quality. Basically the USA standards seem to be more tolerant for these new innovative technologies. New standard proposals use signal/noise ratio and unsharpness as dominant parameters for image quality. Specialised measurement procedures are described. The properties of the new detectors can be controlled by electronics and exposure conditions. New names appear in literature like 'direct radiography' and 'film replacement techniques'. The basic advantage of the new digital techniques is the possibility to use numeric procedures for image interpretation. Industrial radiology can be optimised for crack detection as well as for analysis of flaw depth and shape measurement. Automated flaw detection, measurement of part dimensions and detection of completeness are used for serial part inspection devices. Parallel to the development of DDA's, an extraordinary increase of Computed Tomography (CT) applications can be observed. (author)

  13. Radiation dose of digital tomosynthesis for sinonasal examination: comparison with multi-detector CT.

    Science.gov (United States)

    Machida, Haruhiko; Yuhara, Toshiyuki; Tamura, Mieko; Numano, Tomokazu; Abe, Shinji; Sabol, John M; Suzuki, Shigeru; Ueno, Eiko

    2012-06-01

    Using an anthropomorphic phantom, we have investigated the feasibility of digital tomosynthesis (DT) of flat-panel detector (FPD) radiography to reduce radiation dose for sinonasal examination compared to multi-detector computed tomography (MDCT). A female Rando phantom was scanned covering frontal to maxillary sinus using the clinically routine protocol by both 64-detector CT (120 kV, 200 mAs, and 1.375-pitch) and DT radiography (80 kV, 1.0 mAs per projection, 60 projections, 40° sweep, and posterior-anterior projections). Glass dosimeters were used to measure the radiation dose to internal organs including the thyroid gland, brain, submandibular gland, and the surface dose at various sites including the eyes during those scans. We compared the radiation dose to those anatomies between both modalities. In DT radiography, the doses of the thyroid gland, brain, submandibular gland, skin, and eyes were 230 ± 90 μGy, 1770 ± 560 μGy, 1400 ± 80 μGy, 1160 ± 2100 μGy, and 112 ± 6 μGy, respectively. These doses were reduced to approximately 1/5, 1/8, 1/12, 1/17, and 1/290 of the respective MDCT dose. For sinonasal examinations, DT radiography enables dramatic reduction in radiation exposure and dose to the head and neck region, particularly to the lens of the eye. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  14. Recent developments in radiography

    International Nuclear Information System (INIS)

    Berger, Harold

    1982-01-01

    Advances in radiography are reviewed and eighty-one references are cited to provide additional information. The review includes information on x-ray sources in terms of output, portability and imaging geometry and detectors in terms of films and screens, electrostatic methods, real-time techniques and solid state devices. Inspection methods utilizing radiations other than x-rays, neutrons and charged particles, expand the inspection problems suitable for radiography. Techniques such as tomography, digital radiography and image enhancement are described. Tomography, in particular, provides excellent capability to characterize materials and discontinuities

  15. Neutron radiography of thick hydrogenous materials with use of an imaging plate neutron detector

    International Nuclear Information System (INIS)

    Kato, K.; Matsumoto, G.; Karasawa, Y.; Niimura, N.; Matsubayashi, M.; Tsuruno, A.

    1996-01-01

    The value of the neutron mass attenuation coefficient of hydrogen being very high, it is extremely difficult to image normal size, living animals with neutron radiography. However, the authors suggest the possibility of applying neutron radiography for biomedical specimens. The organs in the breast, bones and cartilages in the extremities, and the tail of mice and rats were clearly imaged by neutron radiography with Gd foils as neutron converters and X-ray films. However, no contours of the organs in the mouse abdomen were visible with neutron radiography with an exposure time of 200 s. By adding Gd or Li compounds as neutron converters to imaging X-ray plates, imaging plates have been developed for neutron detectors. A trial using these imaging plates for neutron radiography of water-filled containers and the abdomen of mice was completed. The roundness of a 100 ml-beaker was imaged with a neutron exposure of 180 s. Obscure contours of the liver and kidneys of the mouse were imaged with a neutron exposure of 100 s. (orig.)

  16. Role of digital tomosynthesis and dual energy subtraction digital radiography in detection of parenchymal lesions in active pulmonary tuberculosis

    International Nuclear Information System (INIS)

    Sharma, Madhurima; Sandhu, Manavjit Singh; Gorsi, Ujjwal; Gupta, Dheeraj; Khandelwal, Niranjan

    2015-01-01

    Highlights: • Digital tomosynthesis and dual energy subtraction digital radiography are modifications of digital radiography. • These modalities perform better than digital radiography in detection of parenchymal lesions in active pulmonary tuberculosis. • Digital tomosynthesis has a sensitivity of 100% in detection of cavities. • Centrilobular nodules seen on CT in active pulmonary tuberculosis, were also demonstrated on digital tomosynthesis in our study. • Digital tomosynthesis can be used for diagnosis and follow up of patients in pulmonary tuberculosis, thereby reducing the number of CT examinations. - Abstract: Objective: To assess the role of digital tomosynthesis (DTS) and dual energy subtraction digital radiography (DES-DR) in detection of parenchymal lesions in active pulmonary tuberculosis (TB) and to compare them with digital radiography (DR). Materials and methods: This prospective study was approved by our institutional review committee. DTS and DES-DR were performed in 62 patients with active pulmonary TB within one week of multidetector computed tomography (MDCT) study. Findings of active pulmonary TB, that is consolidation, cavitation and nodules were noted on digital radiography (DR), DTS and DES-DR in all patients. Sensitivity, specificity, positive and negative predictive values of all 3 modalities was calculated with MDCT as reference standard. In addition presence of centrilobular nodules was also noted on DTS. Results: Our study comprised of 62 patients (33 males, 29 females with age range 18–82 years). Sensitivity and specificity of DTS for detection of nodules and cavitation was better than DR and DES-DR. Sensitivity and specificity of DTS for detection of consolidation was comparable to DR and DES-DR. DES-DR performed better than DR in detection of nodules and cavitation. DTS was also able to detect centrilobular nodules with sensitivity and specificity of 57.4% and 86.5% respectively. Conclusion: DTS and DES-DR perform better

  17. Role of digital tomosynthesis and dual energy subtraction digital radiography in detection of parenchymal lesions in active pulmonary tuberculosis

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Madhurima, E-mail: madhurimashrm88@gmail.com [Department of Radiodiagnosis and Imaging, PGIMER, Chandigarh 160012 (India); Sandhu, Manavjit Singh, E-mail: manavjitsandhu@yahoo.com [Department of Radiodiagnosis and Imaging, PGIMER, Chandigarh 160012 (India); Gorsi, Ujjwal, E-mail: ujjwalgorsi@gmail.com [Department of Radiodiagnosis and Imaging, PGIMER, Chandigarh 160012 (India); Gupta, Dheeraj, E-mail: dheeraj1910@gmail.com [Department of Pulmonary Medicine, PGIMER, Chandigarh 160012 (India); Khandelwal, Niranjan, E-mail: khandelwaln@hotmail.com [Department of Radiodiagnosis and Imaging, PGIMER, Chandigarh 160012 (India)

    2015-09-15

    Highlights: • Digital tomosynthesis and dual energy subtraction digital radiography are modifications of digital radiography. • These modalities perform better than digital radiography in detection of parenchymal lesions in active pulmonary tuberculosis. • Digital tomosynthesis has a sensitivity of 100% in detection of cavities. • Centrilobular nodules seen on CT in active pulmonary tuberculosis, were also demonstrated on digital tomosynthesis in our study. • Digital tomosynthesis can be used for diagnosis and follow up of patients in pulmonary tuberculosis, thereby reducing the number of CT examinations. - Abstract: Objective: To assess the role of digital tomosynthesis (DTS) and dual energy subtraction digital radiography (DES-DR) in detection of parenchymal lesions in active pulmonary tuberculosis (TB) and to compare them with digital radiography (DR). Materials and methods: This prospective study was approved by our institutional review committee. DTS and DES-DR were performed in 62 patients with active pulmonary TB within one week of multidetector computed tomography (MDCT) study. Findings of active pulmonary TB, that is consolidation, cavitation and nodules were noted on digital radiography (DR), DTS and DES-DR in all patients. Sensitivity, specificity, positive and negative predictive values of all 3 modalities was calculated with MDCT as reference standard. In addition presence of centrilobular nodules was also noted on DTS. Results: Our study comprised of 62 patients (33 males, 29 females with age range 18–82 years). Sensitivity and specificity of DTS for detection of nodules and cavitation was better than DR and DES-DR. Sensitivity and specificity of DTS for detection of consolidation was comparable to DR and DES-DR. DES-DR performed better than DR in detection of nodules and cavitation. DTS was also able to detect centrilobular nodules with sensitivity and specificity of 57.4% and 86.5% respectively. Conclusion: DTS and DES-DR perform better

  18. New possibilities of digital luminescence radiography (DLR) and digital image processing for verification and portal imaging

    International Nuclear Information System (INIS)

    Zimmermann, J.S.; Blume, J.; Wendhausen, H.; Hebbinghaus, D.; Kovacs, G.; Eilf, K.; Schultze, J.; Kimmig, B.N.

    1995-01-01

    We developed a method, using digital luminescence radiography (DLR), not only for portal imaging of photon beams in an excellent quality, but also for verification of electron beams. Furtheron, DLR was used as basic instrument for image fusion of portal and verification film and simulation film respectively for image processing in ''beams-eye-view'' verification (BEVV) of rotating beams or conformation therapy. Digital radiographs of an excellent quality are gained for verification of photon and electron beams. In photon beams, quality improvement vs. conventional portal imaging may be dramatic, even more for high energy beams (e.g. 15-MV-photon beams) than for Co-60. In electron beams, excellent results may be easily obtained. By digital image fusion of 1 or more verification films on simulation film or MRI-planning film, more precise judgement even on small differences between simulation and verification films becomes possible. Using BEVV, it is possible to compare computer aided simulation in rotating beams or conformation therapy with the really applied treatment. The basic principle of BEVV is also suitable for dynamic multileaf collimation. (orig.) [de

  19. Track fitting and resolution with digital detectors

    International Nuclear Information System (INIS)

    Duerdoth, I.

    1982-01-01

    The analysis of data from detectors which give digitised measurements, such as MWPCs, is considered. These measurements are necessarily correlated and it is shown that the uncertainty in the combination of N measurements may fall faster than the canonical 1/√N. A new method of track fitting is described which exploits the digital aspects and which takes the correlations into account. It divides the parameter space into cells and the centroid of a cell is taken as the best estimate. The method is shown to have some advantages over the standard least-squares analysis. If the least-squares method is used for digital detectors the goodness-of-fit may not be a reliable estimate of the accuracy. The cell method is particularly suitable for implementation on microcomputers which lack floating point and divide facilities. (orig.)

  20. Tests of a new CCD-camera based neutron radiography detector system at the reactor stations in Munich and Vienna

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, E; Pleinert, H [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Schillinger, B [Technische Univ. Muenchen (Germany); Koerner, S [Atominstitut der Oesterreichischen Universitaeten, Vienna (Austria)

    1997-09-01

    The performance of the new neutron radiography detector designed at PSI with a cooled high sensitive CCD-camera was investigated under real neutronic conditions at three beam ports of two reactor stations. Different converter screens were applied for which the sensitivity and the modulation transfer function (MTF) could be obtained. The results are very encouraging concerning the utilization of this detector system as standard tool at the radiography stations at the spallation source SINQ. (author) 3 figs., 5 refs.

  1. Accelerated H-LBP-based edge extraction method for digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Shuang; Zhao, Chen-yi; Huang, Ji-peng [School of Physics, Northeast Normal University, Changchun 130024 (China); Sun, Jia-ning, E-mail: sunjn118@nenu.edu.cn [School of Mathematics and Statistics, Northeast Normal University, Changchun 130024 (China)

    2015-01-11

    With the goal of achieving real time and efficient edge extraction for digital radiography, an accelerated H-LBP-based edge extraction method (AH-LBP) is presented in this paper by improving the existing framework of local binary pattern with the H function (H-LBP). Since the proposed method avoids computationally expensive operations with no loss of quality, it possesses much lower computational complexity than H-LBP. Experimental results on real radiographies show desirable performance of our method. - Highlights: • An accelerated H-LBP method for edge extraction on digital radiography is proposed. • The novel AH-LBP relies on numerical analysis of the existing H-LBP method. • Aiming at accelerating, H-LBP is reformulated as a direct binary processing. • AH-LBP provides the same edge extraction result as H-LBP does. • AH-LBP has low computational complexity satisfying real time requirements.

  2. Searching early bone metastasis on plain radiography by using digital imaging processing

    Energy Technology Data Exchange (ETDEWEB)

    Jaramillo-Nunez, A.; Perez-Meza, M. [Instituto Nacional de Astrofisica, Optica y Electronica, Apdo. Postal 51 y 216, Pue. (Mexico); Universidad de la Sierra Sur, C. P. 70800, Miahuatlan, Oax. (Mexico)

    2012-10-23

    Some authors mention that it is not possible to detect early bone metastasis on plain radiography. In this work we use digital imaging processing to analyze three radiographs taken from a patient with bone metastasis discomfort on the right shoulder. The time period among the first and second radiography was approximately one month and between the first and the third one year. This procedure is a first approach in order to know if in this particular case it was possible to detect an early bone metastasis. The obtained results suggest that by carrying out a digital processing is possible to detect the metastasis since the radiography contains the information although visually it is not possible to observe it.

  3. [Digital radiography in young children. Considerations based on experiences in practice].

    Science.gov (United States)

    Berkhout, W E R; Mileman, P A; Weerheijm, K L

    2004-10-01

    In dentistry, digital radiology techniques, such as a charge-coupled device and a storage phosphor plate, are gaining popularity. It was the objective of this study to assess the importance of the advantages and disadvantages of digital radiology techniques for bitewing radiography in young children, when compared to conventional film. A group of dentists received a questionnaire regarding their experiences with digital radiology techniques or conventional films among young children. Using the Simple Multi-Attributive Rating Technique (SMART) a final weighted score was calculated for the charge-coupled device, the phosphor plate, and conventional film. The scores were 7.40, 7.38, and 6.98 respectively. The differences were not statistically significant (p > 0.47). It could be concluded that, on the basis of experiences in practice, there are no statistically significant preferences for the use of digital radioogy techniques for bitewing radiography in young children.

  4. Large area x-ray detectors for cargo radiography

    Science.gov (United States)

    Bueno, C.; Albagli, D.; Bendahan, J.; Castleberry, D.; Gordon, C.; Hopkins, F.; Ross, W.

    2007-04-01

    Large area x-ray detectors based on phosphors coupled to flat panel amorphous silicon diode technology offer significant advances for cargo radiologic imaging. Flat panel area detectors provide large object coverage offering high throughput inspections to meet the high flow rate of container commerce. These detectors provide excellent spatial resolution when needed, and enhanced SNR through low noise electronics. If the resolution is reduced through pixel binning, further advances in SNR are achievable. Extended exposure imaging and frame averaging enables improved x-ray penetration of ultra-thick objects, or "select-your-own" contrast sensitivity at a rate many times faster than LDAs. The areal coverage of flat panel technology provides inherent volumetric imaging with the appropriate scanning methods. Flat panel area detectors have flexible designs in terms of electronic control, scintillator selection, pixel pitch, and frame rates. Their cost is becoming more competitive as production ramps up for the healthcare, nondestructive testing (NDT), and homeland protection industries. Typically used medical and industrial polycrystalline phosphor materials such as Gd2O2S:Tb (GOS) can be applied to megavolt applications if the phosphor layer is sufficiently thick to enhance x-ray absorption, and if a metal radiator is used to augment the quantum detection efficiency and reduce x-ray scatter. Phosphor layers ranging from 0.2-mm to 1-mm can be "sandwiched" between amorphous silicon flat panel diode arrays and metal radiators. Metal plates consisting of W, Pb or Cu, with thicknesses ranging from 0.25-mm to well over 1-mm can be used by covering the entire area of the phosphor plate. In some combinations of high density metal and phosphor layers, the metal plate provides an intensification of 25% in signal due to electron emission from the plate and subsequent excitation within the phosphor material. This further improves the SNR of the system.

  5. The Use of Digital Radiography in the Evaluation of Radioactive Materials. Packaging Performance Testing

    International Nuclear Information System (INIS)

    May, C; Lawrence Gelder, L; Boyd Howard, B

    2007-01-01

    New designs of radioactive material shipping packages are required to be evaluated in accordance with 10 CFR Part 71, ''Packaging and Transportation of Radioactive Material''. This paper will discuss the use of digital radiography to evaluate the effects of the tests required by 10 CFR 71.71, Normal Conditions of Transport (NCT), and 10 CFR 71.73, Hypothetical Accident Conditions (HAC). One acceptable means of evaluating packaging performance is to subject packagings to the series of NCT and HAC tests. The evaluation includes a determination of the effect on the packaging by the conditions and tests. That determination has required that packagings be cut and sectioned to learn the actual effects on internal components. Digital radiography permits the examination of internal packaging components without sectioning a package. This allows a single package to be subjected to a series of tests. After each test, the package is digitally radiographed and the effects of particular tests evaluated. Radiography reduces the number of packages required for testing and also reduces labor and materials required to section and evaluate numerous packages. This paper will include a description of the digital radiography equipment used in the testing and evaluation of the 9977 and 9978 packages at SRNL. The equipment is capable of making a single radiograph of a full-sized package in one exposure. Radiographs will be compared to sectioned packages that show actual conditions compared to radiographic images

  6. Comparison of conventional panoramic radiography and panoramic digital subtraction radiography in detection of simulated lesions of mandibular condyle

    Directory of Open Access Journals (Sweden)

    Panjnoush M.

    2008-12-01

    Full Text Available "n  "nBackground and Aim: Digital subtraction Radiography (DSR is a method of accurate assessing condylar head changes. several studies have been carried out in applying DSR in dentistry, however there is a few number of studies in efficacy of DSR method in assesment of condylar head changes, The aim of this study was to compare panoramic radiography and DSR detecting simulated lesions of the mandibular condyl. "nMaterials and Methods: this was a process reaserch study, in which two dry human skulls with no obvious temporomandibular joint pathology were used. Osteophytic lesions were simulated using three sizes of bone chips that were placed on the medial portion of anterior and superolateral aspects of the condyle. Osteolytic lesions were simulated making 1 and 2 mm holes using round burr in the central portion of anterior aspect and Lateral pole of the condyle. Panoramic radiographs were prepared with and without the lesions in place. These paired radiographs were digitized and digital- subtraction images of the original panoramic images were obtained. Eight observers evaluated 155 images of each modality for the presence or absence and the type of simulated lesions of the mandibular condyle. Sensitivity, specificity, reliability and measure of agreement were analyzed using kappa test and crossed tables and qualitative variables were assess by chi-square and fisher's Exact test. "nResults: Specificity of panoramic and DSR methods were 15.4% and 66.7% respectively. Sensitivity of panoramic and DSR methods were 61.1% and 80.6% for osteophytic lesions and 37.5% and 83.3% for Osteolytic lesions. The percentage of correct decisions made in DSR method was significantly more than conventional panoramic method (82.6% vs 41.9% (p<0.0001. "nConclusion: Based on the results of this study digital subtraction technique was significantly more accurate than the panoramic radiographs in detection of simulated lesions of the mandibular condyle.

  7. Application of digital image processing to industrial radiography

    International Nuclear Information System (INIS)

    Bodson; Varcin; Crescenzo; Theulot

    1985-01-01

    Radiography is widely used for quality control of fabrication of large reactor components. Image processing methods are applied to industrial radiographs in order to help to take a decision as well as to reduce costs and delays for examination. Films, performed in representative operating conditions, are used to test results obtained with algorithms for the restauration of images and for the detection, characterisation of indications in order to determine the possibility of an automatic radiographs processing [fr

  8. The potential of digital dental radiography in recording the adductor sesamoid and the MP3 stages.

    Science.gov (United States)

    Abdel-Kader, H M

    1999-12-01

    The current study was undertaken to evaluate the reliability of using a recent advance in clinical radiographic technique, digital dental radiography, in recording two growth indicators: the adductor sesamoid and MP3 stages. With an exposure time five times less than that used in the conventional approach, this method shows greatest flexibility in providing a high quality digitized radiographic images of the two growth indicators under investigation. Refereed Paper

  9. Evaluation of the equine digital flexor tendon sheath using diagnostic ultrasound and contrast radiography

    International Nuclear Information System (INIS)

    Redding, W.R.

    1994-01-01

    This study was designed to evaluate the normal anatomy of the digital flexor tendon sheath using contrast radiography and diagnostic ultrasound. Iodinated contrast medium was injected into eight cadaver limbs and the limbs immediately frozen. Lateromedial and dorsopalmar/plantar radiographs were made. These limps were then cut transversely and proximal to distal radiographs of each slab were made. This cross sectional contrast methodology allowed the visualization of the relative size and shape of the superficial and deep digital flexor tendons as well as the potential space taken by effusions of the digital flexor tendon sheath. The second part of the study used twelve live animals with normal digital flexor tendon sheaths. Ultrasonographic measurement of the structures of the digital flexor tendon sheath at each level were compiled. This documented the ability of diagnostic ultrasound to image: 1) the superficial and deep digital flexor tendons, 2) the proximal and distal ring of the manica flexoria, 3) the straight and oblique sesamoidean ligaments, and 4) the mesotendinous attachments to the superficial and deep flexor tendons. Iodinated contrast medium was then injected into the digital flexor tendon sheath and the ultrasonography repeated. These images were compared with those obtained from contrast radiography and prosections of twenty normal limbs. The iodinated contrast medium enhanced sonographic imaging of the structures of the digital tendon sheath, particularly the abaxial borders of the superficial digital flexor tendon branches and the mesotendinous attachments to the superficial and deep digital flexor tendons

  10. The scope of detector Medipix2 in micro-radiography of biological samples

    International Nuclear Information System (INIS)

    Dammer, J.; Weyda, F.; Jakubek, J.; Skrabal, P.; Sopko, V.; Vavrik, D.

    2011-01-01

    We present our experimental setup devoted to high resolution X-ray micro-radiography that is suitable for imaging of small biological samples. The photon source is a FeinFocus micro-focus X-ray tube. The single photon counting pixel device Medipix2 serves as imaging area. Recently used imaging detectors as radiography films or scintillator detectors, cannot visualize required information about inner structure of scanned sample. Detectors Medipix2 do not suffer from so-called dark current noise and work in unlimited dynamic range. These features of detectors confer high quality and high contrast of final images. The radiographic imaging with detectors Medipix2 represents non-invasive and non-destructive method of investigation. Hereby, we demonstrate results of micro-radiographic study of internal structures of tiny biological samples. In addition to morphological and anatomical studies, we would like to present preliminary study of dynamic processes inside of organisms using micro-radiographic video-capturing.

  11. The scope of detector Medipix2 in micro-radiography of biological samples

    Energy Technology Data Exchange (ETDEWEB)

    Dammer, J., E-mail: jiri.dammer@utef.cvut.cz [Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a/22, CZ-12800 Prague 2 (Czech Republic); Weyda, F. [Biology Centre of the Academy of Sciences of the Czech Republic, Institute of Entomology, Branisovska 31, CZ-37005 Ceske Budejovice (Czech Republic); Faculty of Science, University of South Bohemia, Branisovska 31, CZ-37005 Ceske Budejovice (Czech Republic); Jakubek, J. [Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a/22, CZ-12800 Prague 2 (Czech Republic); Skrabal, P. [Faculty of Biomedical Engineering, Czech Technical University in Prague, Nam. Sitna 3105, CZ-272 01 Kladno (Czech Republic); Sopko, V.; Vavrik, D. [Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a/22, CZ-12800 Prague 2 (Czech Republic)

    2011-05-15

    We present our experimental setup devoted to high resolution X-ray micro-radiography that is suitable for imaging of small biological samples. The photon source is a FeinFocus micro-focus X-ray tube. The single photon counting pixel device Medipix2 serves as imaging area. Recently used imaging detectors as radiography films or scintillator detectors, cannot visualize required information about inner structure of scanned sample. Detectors Medipix2 do not suffer from so-called dark current noise and work in unlimited dynamic range. These features of detectors confer high quality and high contrast of final images. The radiographic imaging with detectors Medipix2 represents non-invasive and non-destructive method of investigation. Hereby, we demonstrate results of micro-radiographic study of internal structures of tiny biological samples. In addition to morphological and anatomical studies, we would like to present preliminary study of dynamic processes inside of organisms using micro-radiographic video-capturing.

  12. Digital Radiography for Determination of Primary Tooth Length: In Vivo and Ex Vivo Studies

    Directory of Open Access Journals (Sweden)

    Maria D. Basso

    2015-01-01

    Full Text Available Background. Methods for determining the root canal length of the primary tooth should yield accurate and reproducible results. In vitro studies show some limitations, which do not allow their findings to be directly transferred to a clinical situation. Aim. To compare the accuracy of radiographic tooth length obtained from in vivo digital radiograph with that obtained from ex vivo digital radiograph. Method. Direct digital radiographs of 20 upper primary incisors were performed in teeth (2/3 radicular resorption that were radiographed by an intraoral sensor, according to the long-cone technique. Teeth were extracted, measured, and mounted in a resin block, and then radiographic template was used to standardise the sensor-target distance (30 cm. The apparent tooth length (APTL was obtained from the computer screen by means of an electronic ruler accompanying the digital radiography software (CDR 2.0, whereas the actual tooth length (ACTL was obtained by means of a digital calliper following extraction. Data were compared to the ACTL by variance analysis and Pearson’s correlation test. Results. The values for APTL obtained from in vivo radiography were slightly underestimated, whereas those values obtained from ex vivo were slightly overestimated. No significance was observed (P≤0.48 between APTL and ACTL. Conclusion. The length of primary teeth estimated by in vivo and ex vivo comparisons using digital radiography was found to be similar to the actual tooth length.

  13. The evaluation the magnitude radiation exposure dose rate in digital radiography room design

    Science.gov (United States)

    Dwiyanto, Agung; Setia Budi, Wahyu; Hardiman, Gagoek

    2017-12-01

    This study discusses the dose rate in digital radiography room, buit according to meet the provisions of KEMENKES No.1014 / Menkes / SK / XI / 2008 and Regulation of BAPETEN No. 8 / 2011. The provisions primary concern of radiation safety, not comfort, by considering the space design. There are five aspects to consider in designing the space: functionality, comfort, security, movement activities and aesthetics. However provisions only met three aspects of the design, which are a function, security and movement activity. Therefore, it is necessary to evaluate digital radiography room in terms of its ability to control external radiation exposure to be safe and comfortable The dose rate is measured by the range of primary and secondary radiation in the observation points by using Surveymeter. All data are obtained by the preliminary survey prior to the study. Furthermore, the review of digital radiography room is done based on architectural design theory. The dose rate for recommended improvement room is recalculated using the same method as the actual room with the help of computer modeling. The result of dose rate calculation at the inner and outer part of digital radiography observation room shows that in-room dose for a week at each measuring point exceeds the allowable dose limit both for staff and public. During a week of observation, the outdoor dose at some measuring points exceeds the dose limit set by the KEMENKES No.1014 / Menkes / SK / XI / 2008 and Regulation BEPETEN No 8/2011. Meanwhile, the result of dose rate calculation in the inner and outer part of the improved digital radiography room can meet the applicable regulations better.

  14. Lumbar spine radiography — poor collimation practices after implementation of digital technology

    Science.gov (United States)

    Zetterberg, L G; Espeland, A

    2011-01-01

    Objectives The transition from analogue to digital radiography may have reduced the motivation to perform proper collimation, as digital techniques have made it possible to mask areas irradiated outside the area of diagnostic interest (ADI). We examined the hypothesis that collimation practices have deteriorated since digitalisation. Methods After defining the ADI, we compared the proportion of the irradiated field outside the ADI in 86 digital and 86 analogue frontal lumbar spine radiographs using the Mann–Whitney test. 50 digital images and 50 analogue images were from a Norwegian hospital and the remainder from a Danish hospital. Consecutive digital images were compared with analogue images (from the hospitals' archives) produced in the 4 years prior to digitalisation. Both hospitals' standard radiographic procedures remained unchanged during the study. For digital images, the irradiated field was assessed using non-masked raw-data images. Results The proportion of the irradiated field outside the ADI was larger in digital than in analogue images (mean 61.7% vs 42.4%, p<0.001), and also in a subsample of 39 image pairs that could be matched for patient age (p<0.001). The mean total field size was 46% larger in digital than in analogue images (791 cm2 vs 541 cm2). Conclusion Following the implementation of digital radiography, considerably larger areas were irradiated. This causes unnecessarily high radiation doses to patients. PMID:21606070

  15. Lumbar spine radiography--poor collimation practices after implementation of digital technology.

    Science.gov (United States)

    Zetterberg, L G; Espeland, A

    2011-06-01

    The transition from analogue to digital radiography may have reduced the motivation to perform proper collimation, as digital techniques have made it possible to mask areas irradiated outside the area of diagnostic interest (ADI). We examined the hypothesis that collimation practices have deteriorated since digitalisation. After defining the ADI, we compared the proportion of the irradiated field outside the ADI in 86 digital and 86 analogue frontal lumbar spine radiographs using the Mann-Whitney test. 50 digital images and 50 analogue images were from a Norwegian hospital and the remainder from a Danish hospital. Consecutive digital images were compared with analogue images (from the hospitals' archives) produced in the 4 years prior to digitalisation. Both hospitals' standard radiographic procedures remained unchanged during the study. For digital images, the irradiated field was assessed using non-masked raw-data images. The proportion of the irradiated field outside the ADI was larger in digital than in analogue images (mean 61.7% vs 42.4%, p<0.001), and also in a subsample of 39 image pairs that could be matched for patient age (p<0.001). The mean total field size was 46% larger in digital than in analogue images (791 cm(2) vs 541 cm(2)). Following the implementation of digital radiography, considerably larger areas were irradiated. This causes unnecessarily high radiation doses to patients.

  16. Characterization of a clinical unit for digital radiography based on irradiation side sampling technology

    Energy Technology Data Exchange (ETDEWEB)

    Rivetti, Stefano [Fisica Medica, Ospedale di Sassuolo S.p.A., 41049 Sassuolo (Italy); Lanconelli, Nico [Alma Mater Studiorum, Physics Department, University of Bologna, 40127 Bologna (Italy); Bertolini, Marco; Nitrosi, Andrea [Medical Physics Unit, Azienda Ospedaliera ASMN, Istituto di Ricovero e Cura a Carattere Scientifico, 42123 Reggio Emilia (Italy); Burani, Aldo [Ospedale di Sassuolo S.p.A., 41049 Sassuolo (Italy)

    2013-10-15

    Purpose: A characterization of a clinical unit for digital radiography (FUJIFILM FDR D-EVO) is presented. This system is based on the irradiation side sampling (ISS) technology and can be equipped with two different scintillators: one traditional gadolinium-oxysulphide phosphor (GOS) and a needle structured cesium iodide (CsI) phosphor panel.Methods: The characterization was achieved in terms of response curve, modulation transfer function (MTF), noise power spectra (NPS), detective quantum efficiency (DQE), and psychophysical parameters (contrast-detail analysis with an automatic reading of CDRAD images). For both scintillation screens the authors accomplished the measurements with four standard beam conditions: RAQ3, RQA5, RQA7, and RQA9.Results: At the Nyquist frequency (3.33 lp/mm) the MTF is about 35% and 25% for CsI and GOS detectors, respectively. The CsI scintillator has better noise properties than the GOS screen in almost all the conditions. This is particularly true for low-energy beams, where the noise for the GOS system can go up to a factor 2 greater than that found for CsI. The DQE of the CsI detector reaches a peak of 60%, 60%, 58%, and 50% for the RQA3, RQA5, RQA7, and RQA9 beams, respectively, whereas for the GOS screen the maximum DQE is 40%, 44%, 44%, and 35%. The contrast-detail analysis confirms that in the majority of cases the CsI scintillator is able to provide improved outcomes to those obtained with the GOS screen.Conclusions: The limited diffusion of light produced by the ISS reading makes possible the achievement of very good spatial resolution. In fact, the MTF of the unit with the CsI panel is only slightly lower to that achieved with direct conversion detectors. The combination of very good spatial resolution, together with the good noise properties reached with the CsI screen, allows achieving DQE on average about 1.5 times greater than that obtained with GOS. In fact, the DQE of unit equipped with CsI is comparable to the best

  17. Reducing methods of patients exposed dose using auto exposure control system in digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Seong Gyu [Dept. of Diagnostic Radiology, Dong A University Medical Center, Busan (Korea, Republic of)

    2013-06-15

    This study was carried out to reduce patient dose through focus-detector distance, kilovoltage, and a combination of copper filters. In the C, L-spine lateral, Skull AP views were obtained by making changes of 60-100 kV in tube voltage and of 100-200 cm in focus-detector distance and by adding a copper filter when using an auto exposure control device in the digital radiography equipment. The incident dose showed 90 kV, 0.3 mmCu in C-spine lateral with 0.06 mGy under the condition of 200 cm; 100 kV, 0.3 mmCu with 0.40 mGy under the condition of 200 cm and 90 kV 0.3 mmCu in Skull AP with the lowest value of 0.24 mGy under the condition of 140 cm. It was observed that entrance surface dose decreased the most when was increased by 150 cm, 70 kV (C-spine lateral), 81 kV (L-spine lateral). It was also found out that as the between the focus-detector increased in the expansion of the video decreased but the difference was not significant when the distance was 180 cm or more. Skull AP showed the most reduction in the entrance surface dose when the tube voltage was changed by 80 kV, 0.1 mmCu, and 120 cm. Therefore, when using the automatic exposure control device, it is recommended to use the highest tube voltage if possible and to increase focus-detector distance at least by 150-200 cm in wall and 120-140 cm in table in consideration of the radiotechnologist's physical conditions, and to combine 0.1-0.3 mmCu and higher filters. It is thus expected to reduce patient dose by avoiding distortion of images and reducing the entrance surface dose.

  18. Wall thickness measurements using digital radiography - state of the art

    International Nuclear Information System (INIS)

    Wawrzinek, T.; Zscherpel, U.; Bellon, C.

    1997-01-01

    Projection radiography is a method long since used for wall thickness measurements in pipes. Another method sometimes applied is thickness determination based on measuring changes of the optical density by using radioactive isotopes, as in this case the effects of stray radiation are negligible. The two methods hitherto were to be performed manually, and wall thickness data were derived by calculations with a pocket calculator. The required measuring and calculating work can now be automated by way of computerized processing of digitised images. The paper presents the software for automated evaluation of data of a selected location after system calibration. (orig./CB) [de

  19. Comparison of the perceived image quality between two digital imaging systems for neonatal bedside radiography – A case study

    International Nuclear Information System (INIS)

    Zyl, S.A. van; Kekana, R.M.

    2015-01-01

    Background: Chest X-rays are performed daily in the neonatal intensive care and high care units. The skill of the radiographer is critical for obtaining the best image quality and limiting the patient's radiation exposure. The literature states that indirect flat panel detectors produce images of superior quality in comparison to computed radiography systems. At Steve Biko Academic Hospital a decision was made to revert from the direct digital radiography (DR) system to the computed radiography (CR) system, due to poor image quality experienced. Method: The case study objective was to conduct a comparative analysis describing key technical factors contributing to image quality. The analysis entailed retrospectively comparing the images obtained during 2010 and 2011. An image analysis form was utilised in evaluating the technical aspects of the image. A total of 160 images were viewed by 16 participants sampled from the radiography, radiology and paediatric departments. The participants were asked to re-evaluate two of their allotted images after five days to determine their reliability. Results: Findings were that the DR system provides significantly better image quality than the CR system (p < 0.05) for all the technical factors evaluated. However technical improvements are recommended. A wide variance in intra-observer reliability was also found. Conclusion: This case study demonstrated that DR images were considered to be superior to CR images. Recommendations include: a standardised technique for imaging the neonates; optimisation of the imaging software for the digital detectors, improved feedback systems in terms of exposure index values, and the training of radiographers and referring physicians in technical image analysis. - Highlights: • DR system provides better image quality than the CR system for all technical factors evaluated. • The average values obtained from the VAS showed that the DR system still needs to be optimised. • There is need

  20. The limit values for brightness and contrast adjustment in digital panoramic radiography

    Science.gov (United States)

    Zahra, A. T.; Syahraini, S. I.; Kiswanjaya, B.; Ustriyana, P.

    2017-08-01

    There is an overall lack of studies about digital panoramic radiography. The application of image enhancement techniques is still being done based on the operator’s preferences, since there is no objective limitation. The aim is to evaluate the limit values of the brightness and contrast adjustment in digital panoramic radiography. Digital panoramic radiographs were divided into three groups (dark, medium, and light), and the contrast and brightness adjustments were done using Digora for Windows. The static evaluations were done using three criteria: 1 if the image had lower quality, 2 if there was no difference and 3 if the image had better quality. The radiographic changes differed in each group depending on the initial imaging conditions. The brightness adjustment limit values in the dark and medium groups were -10 and +20, respectively, and -20 and +10 in the light group. The contrast adjustment limit values in all of the groups were -10 and +10.

  1. Proximal caries detection using digital subtraction radiography in the artificial caries activity model

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Hoon; Lee, Gi Ja; Choi, Sam Jin; Park, Young Ho; Kim, Kyung Soo; Jin, Hyun Seok; Hong, Kyung Won; Oh, Berm Seok; Park, Hun Kuk [Department of Biomedical Engineering, School of Medicine, Kyung Hee University, Seoul (Korea, Republic of); Choi, Yong Suk; Hwang, Eui Hwan [Department of Oral and Maxillofacial Radiology, Institute of Oral Biology, School of Dentistry, Kyung Hee University, Seoul (Korea, Republic of)

    2009-03-15

    The purpose of the experiment was to evaluating the diagnostic ability of dental caries detection using digital subtraction in the artificial caries activity model. Digital radiographs of five teeth with 8 proximal surfaces were obtained by CCD sensor (Kodak RVG 6100 using a size no.2). The digital radiographic images and subtraction images from artificial proximal caries were examined and interpreted. In this study, we proposed novel caries detection method which could diagnose the dental proximal caries from single digital radiographic image. In artificial caries activity model, the range of lesional depth was 572-1,374 {mu}m and the range of lesional area was 36.95-138.52 mm{sup 2}. The lesional depth and the area were significantly increased with demineralization time (p<0.001). Furthermore, the proximal caries detection using digital subtraction radiography showed high detection rate compared to the proximal caries examination using simple digital radiograph. The results demonstrated that the digital subtraction radiography from single radiographic image of artificial caries was highly efficient in the detection of dental caries compared to the data from simple digital radiograph.

  2. Proximal caries detection using digital subtraction radiography in the artificial caries activity model

    International Nuclear Information System (INIS)

    Park, Jong Hoon; Lee, Gi Ja; Choi, Sam Jin; Park, Young Ho; Kim, Kyung Soo; Jin, Hyun Seok; Hong, Kyung Won; Oh, Berm Seok; Park, Hun Kuk; Choi, Yong Suk; Hwang, Eui Hwan

    2009-01-01

    The purpose of the experiment was to evaluating the diagnostic ability of dental caries detection using digital subtraction in the artificial caries activity model. Digital radiographs of five teeth with 8 proximal surfaces were obtained by CCD sensor (Kodak RVG 6100 using a size no.2). The digital radiographic images and subtraction images from artificial proximal caries were examined and interpreted. In this study, we proposed novel caries detection method which could diagnose the dental proximal caries from single digital radiographic image. In artificial caries activity model, the range of lesional depth was 572-1,374 μm and the range of lesional area was 36.95-138.52 mm 2 . The lesional depth and the area were significantly increased with demineralization time (p<0.001). Furthermore, the proximal caries detection using digital subtraction radiography showed high detection rate compared to the proximal caries examination using simple digital radiograph. The results demonstrated that the digital subtraction radiography from single radiographic image of artificial caries was highly efficient in the detection of dental caries compared to the data from simple digital radiograph.

  3. FINAL SCIENTIFIC REPORT - PROTON RADIOGRAPHY: CROSS SECTION MEASUREMENTS AND DETECTOR DEVELOPMENT

    International Nuclear Information System (INIS)

    Longo, Michael J.; Gustafson, H. Richard.; Rajaram, Durga; Nigmanov, Turgun

    2007-01-01

    Proton radiography offers significant advantages over conventional X-ray radiography, including the capability of looking into thick, dense materials, better contrast for a wide range of materials, sensitivity to different materials of similar density, and better resolution because of the ability to focus beams. In order to achieve this capability it is crucial to understand the background due to neutrons and photons and to develop techniques to reduce it to tolerable levels. The physics goal of this project is to measure forward production of neutrons and photons produced by high-energy proton beams striking a variety of targets. This work is being carried out in conjunction with the Fermilab Experiment 907 (MIPP) collaboration including physicists from Lawrence Livermore Laboratory. Our group is responsible for the E907 forward neutron/photon calorimeters. These are the only detectors in the experiment that provide information on neutrons and photons. We are taking a leading role in obtaining and analyzing the for-ward production data and in developing an optimal detector for proton radiography. With the support of our Stewardship Science Academic Alliances grant, we were able to design, build, and commission the calorimeters on budget and ahead of schedule. E-907 officially started physics running at Fermilab in January 2005, and data taking continued through February 2006. Data were taken on a range of targets, from liquid hydrogen to uranium, at beam energies from 5 GeV/c to 120 GeV/c. The analysis of the data is challenging because data from many different detector systems must be understood and merged and over 31 million events were accumulated. Our recent efforts have been devoted to the calibration of the neutron and photon detectors, to track and shower reconstruction, identification of forward-going neutrons, and simulation of the calorimeters in a Monte Carlo. Reconstruction of the data with improved tracking is underway

  4. Dose-image quality study in digital chest radiography using Monte Carlo simulation

    International Nuclear Information System (INIS)

    Correa, S.C.A.; Souza, E.M.; Silva, A.X.; Lopes, R.T.; Yoriyaz, H.

    2008-01-01

    One of the main preoccupations of diagnostic radiology is to guarantee a good image-sparing dose to the patient. In the present study, Monte Carlo simulations, with MCNPX code, coupled with an adult voxel female model (FAX) were performed to investigate how image quality and dose in digital chest radiography vary with tube voltage (80-150 kV) using air-gap technique and a computed radiography system. Calculated quantities were normalized to a fixed value of entrance skin exposure (ESE) of 0.0136 R. The results of the present analysis show that the image quality for chest radiography with imaging plate is improved and the dose reduced at lower tube voltage

  5. Multi-Institutional Evaluation of Digital Tomosynthesis, Dual-Energy Radiography, and Conventional Chest Radiography for the Detection and Management of Pulmonary Nodules.

    Science.gov (United States)

    Dobbins, James T; McAdams, H Page; Sabol, John M; Chakraborty, Dev P; Kazerooni, Ella A; Reddy, Gautham P; Vikgren, Jenny; Båth, Magnus

    2017-01-01

    Purpose To conduct a multi-institutional, multireader study to compare the performance of digital tomosynthesis, dual-energy (DE) imaging, and conventional chest radiography for pulmonary nodule detection and management. Materials and Methods In this binational, institutional review board-approved, HIPAA-compliant prospective study, 158 subjects (43 subjects with normal findings) were enrolled at four institutions. Informed consent was obtained prior to enrollment. Subjects underwent chest computed tomography (CT) and imaging with conventional chest radiography (posteroanterior and lateral), DE imaging, and tomosynthesis with a flat-panel imaging device. Three experienced thoracic radiologists identified true locations of nodules (n = 516, 3-20-mm diameters) with CT and recommended case management by using Fleischner Society guidelines. Five other radiologists marked nodules and indicated case management by using images from conventional chest radiography, conventional chest radiography plus DE imaging, tomosynthesis, and tomosynthesis plus DE imaging. Sensitivity, specificity, and overall accuracy were measured by using the free-response receiver operating characteristic method and the receiver operating characteristic method for nodule detection and case management, respectively. Results were further analyzed according to nodule diameter categories (3-4 mm, >4 mm to 6 mm, >6 mm to 8 mm, and >8 mm to 20 mm). Results Maximum lesion localization fraction was higher for tomosynthesis than for conventional chest radiography in all nodule size categories (3.55-fold for all nodules, P chest radiography for all nodules (1.49-fold, P chest radiography, as given by the area under the receiver operating characteristic curve (1.23-fold, P chest radiography or tomosynthesis. Conclusion Tomosynthesis outperformed conventional chest radiography for lung nodule detection and determination of case management; DE imaging did not show significant differences over conventional chest

  6. Radiography

    International Nuclear Information System (INIS)

    Hounsfield, G.N.

    1976-01-01

    Radiographic apparatus is described in which a thin planar slice of the body is examined by a swath of penetrating radiation such as X-rays. Collimators are provided for collimating the radiation after it has passed through the body into a set of beams which are directed into respective detectors. The swath of radiation, the collimeters and the detectors are orbited in the plane of the slice so that the beams pass through the body from many different angular directions. Means are provided for additionally displacing at least the collimators relative to the source so that the relative position of the beams and gaps between the beams are changed during the orbital movement

  7. Digital subtraction cardiopulmonary angiography using FCR (Fuji computed radiography)

    International Nuclear Information System (INIS)

    Tanimura, Shigeo; Tomoyasu, Hiroshi; Banba, Jiro; Masaki, Mikio; Kanno, Yukio; Abe, Kazuo

    1987-01-01

    Digital subtraction cardiopulmonary angiography using FCR was performed on 46 patients including lung cancer, mediastinal tumor, giant bullous formation and others. The images of digital subtraction for pulmonary artery, pulmonary vein and thoracic aorta were studied by comparing to the conventional pulmonary angiogram. Good images of pulmonary artery due to digital subtraction were obtained in 80 % of the 45 cases. This method needed only half volume of contrast media compared to the conventional for obtaining good images and thus reduced side effect. Therefore this method seems to be an usefull pre-operative examination in various chest diseases, especially in case of lung cancer. (author)

  8. Preliminary clinical evaluation of hard- and soft-copy digitized chest radiography

    Science.gov (United States)

    Rian, Roger L.; Smerud, Michael J.; Guinn, Todd

    1994-05-01

    The digital applications in radiology are a controversial advanced which potentially will influence all areas of patient imaging. It is utilized and accepted in angiography, computed tomography, magnetic resonance, nuclear imaging and sonography. More recently Computed Radiography has gained credibility in mobile scenarios as well as specific applications from cervical spine radiography to digital fluoroscopy. Usually this acceptance is related to benefits of lesser radiation exposure or an improved presentation with an incorrect radiographic technique. One advantage of interpreting from digital information is the potential manipulation of the image presentation to the observer through windowing, leveling and edge enhancement pre and/or during image review. Additionally this digital data can be transmitted over distance and represented as hard and/or soft copy for primary or consultative review. The number and quality of the images to be viewed, the environment of the review station as well as the observer experience with conventional radiographic as well as digital image evaluation are important aspects of delivering the radiologist's product i.e. the final interpretation. This paper assesses that product, specifically addressing the question `Is the radiologist's report the same whether derived from the original analog image or from its digitized image.' The object of this study is to determine whether a digital system (3M PACS) designed for consultative viewing in a satellite department can also be used directly for primary diagnosis of conventional chest exams.

  9. Screen-film versus digital radiography of sacroiliac joints: Evaluation of image quality and dose to patients

    International Nuclear Information System (INIS)

    Jablanovic, D.; Ciraj-Bjelac, O.; Damjanov, N.; Seric, S.; Radak-Perovic, M.; Arandjic, D.; Maksimovic, R.

    2013-01-01

    The purpose of this paper is to evaluate the image quality and dose to patients in the radiography of sacroiliac joints and to perform a clinical comparative study of digital and conventional screen-film radiography. Routine radiography of sacroiliac joint was performed in 60 patients using digital and screen-film radiography. The visibility of five anatomical regions and the overall image quality were rated by experienced radiologists. Patient dose assessment in terms of entrance surface air kerma (ESAK) was performed. The digital system showed slightly improved visualisation of specific anatomical structures. Overall image quality was significantly better in the digital when compared with the screen-film imaging system. The average ESAK was 2.4 mGy in screen-film and 3.6 mGy in digital radiography. The digital radiography provided equal or better visibility of anatomical details and overall image quality, but on higher dose levels. Therefore, the practice on digital systems must be optimised. (authors)

  10. Simulation study of pixel detector charge digitization

    Science.gov (United States)

    Wang, Fuyue; Nachman, Benjamin; Sciveres, Maurice; Lawrence Berkeley National Laboratory Team

    2017-01-01

    Reconstruction of tracks from nearly overlapping particles, called Tracking in Dense Environments (TIDE), is an increasingly important component of many physics analyses at the Large Hadron Collider as signatures involving highly boosted jets are investigated. TIDE makes use of the charge distribution inside a pixel cluster to resolve tracks that share one of more of their pixel detector hits. In practice, the pixel charge is discretized using the Time-over-Threshold (ToT) technique. More charge information is better for discrimination, but more challenging for designing and operating the detector. A model of the silicon pixels has been developed in order to study the impact of the precision of the digitized charge distribution on distinguishing multi-particle clusters. The output of the GEANT4-based simulation is used to train neutral networks that predict the multiplicity and location of particles depositing energy inside one cluster of pixels. By studying the multi-particle cluster identification efficiency and position resolution, we quantify the trade-off between the number of ToT bits and low-level tracking inputs. As both ATLAS and CMS are designing upgraded detectors, this work provides guidance for the pixel module designs to meet TIDE needs. Work funded by the China Scholarship Council and the Office of High Energy Physics of the U.S. Department of Energy under contract DE-AC02-05CH11231.

  11. Semiconductor pixel detectors for digital mammography

    International Nuclear Information System (INIS)

    Novelli, M.; Amendolia, S.R.; Bisogni, M.G.; Boscardin, M.; Dalla Betta, G.F.; Delogu, P.; Fantacci, M.E.; Quattrocchi, M.; Rosso, V.; Stefanini, A.; Venturelli, L.; Zucca, S.

    2003-01-01

    We present some results obtained with silicon and gallium arsenide pixel detectors to be applied in the field of digital mammography. Even though GaAs is suitable for medical imaging applications thanks to its atomic number, which allows a very good detection efficiency, it often contains an high concentrations of traps which decrease the charge collection efficiency (CCE). So we have analysed both electrical and spectroscopic performance of different SI GaAs diodes as a function of concentrations of dopants in the substrate, in order to find a material by which we can obtain a CCE allowing the detection of all the photons that interact in the detector. Nevertheless to be able to detect low contrast details, efficiency and CCE are not the only parameters to be optimized; also the stability of the detection system is fundamental. In the past we have worked with Si pixel detectors; even if its atomic number does not allow a good detection efficiency at standard thickness, it has a very high stability. So keeping in mind the need to increase the Silicon detection efficiency we performed simulations to study the behaviour of the electrical potential in order to find a geometry to avoid the risk of electrical breakdown

  12. Semiconductor pixel detectors for digital mammography

    Energy Technology Data Exchange (ETDEWEB)

    Novelli, M. E-mail: marzia.novelli@pi.infn.it; Amendolia, S.R.; Bisogni, M.G.; Boscardin, M.; Dalla Betta, G.F.; Delogu, P.; Fantacci, M.E.; Quattrocchi, M.; Rosso, V.; Stefanini, A.; Venturelli, L.; Zucca, S

    2003-08-21

    We present some results obtained with silicon and gallium arsenide pixel detectors to be applied in the field of digital mammography. Even though GaAs is suitable for medical imaging applications thanks to its atomic number, which allows a very good detection efficiency, it often contains an high concentrations of traps which decrease the charge collection efficiency (CCE). So we have analysed both electrical and spectroscopic performance of different SI GaAs diodes as a function of concentrations of dopants in the substrate, in order to find a material by which we can obtain a CCE allowing the detection of all the photons that interact in the detector. Nevertheless to be able to detect low contrast details, efficiency and CCE are not the only parameters to be optimized; also the stability of the detection system is fundamental. In the past we have worked with Si pixel detectors; even if its atomic number does not allow a good detection efficiency at standard thickness, it has a very high stability. So keeping in mind the need to increase the Silicon detection efficiency we performed simulations to study the behaviour of the electrical potential in order to find a geometry to avoid the risk of electrical breakdown.

  13. Design and theoretical investigation of a digital x-ray detector with large area and high spatial resolution

    Science.gov (United States)

    Gui, Jianbao; Guo, Jinchuan; Yang, Qinlao; Liu, Xin; Niu, Hanben

    2007-05-01

    X-ray phase contrast imaging is a promising new technology today, but the requirements of a digital detector with large area, high spatial resolution and high sensitivity bring forward a large challenge to researchers. This paper is related to the design and theoretical investigation of an x-ray direct conversion digital detector based on mercuric iodide photoconductive layer with the latent charge image readout by photoinduced discharge (PID). Mercuric iodide has been verified having a good imaging performance (high sensitivity, low dark current, low voltage operation and good lag characteristics) compared with the other competitive materials (α-Se,PbI II,CdTe,CdZnTe) and can be easily deposited on large substrates in the manner of polycrystalline. By use of line scanning laser beam and parallel multi-electrode readout make the system have high spatial resolution and fast readout speed suitable for instant general radiography and even rapid sequence radiography.

  14. Tolerance of image enhancement brightness and contrast in lateral cephalometric digital radiography for Steiner analysis

    Science.gov (United States)

    Rianti, R. A.; Priaminiarti, M.; Syahraini, S. I.

    2017-08-01

    Image enhancement brightness and contrast can be adjusted on lateral cephalometric digital radiographs to improve image quality and anatomic landmarks for measurement by Steiner analysis. To determine the limit value for adjustments of image enhancement brightness and contrast in lateral cephalometric digital radiography for Steiner analysis. Image enhancement brightness and contrast were adjusted on 100 lateral cephalometric radiography in 10-point increments (-30, -20, -10, 0, +10, +20, +30). Steiner analysis measurements were then performed by two observers. Reliabilities were tested by the Interclass Correlation Coefficient (ICC) and significance tested by ANOVA or the Kruskal Wallis test. No significant differences were detected in lateral cephalometric analysis measurements following adjustment of the image enhancement brightness and contrast. The limit value of adjustments of the image enhancement brightness and contrast associated with incremental 10-point changes (-30, -20, -10, 0, +10, +20, +30) does not affect the results of Steiner analysis.

  15. Digital subtraction radiography in the study of the lacrimal system

    International Nuclear Information System (INIS)

    Falaschi, F.; Pieri, L.; Perri, G.; Signorini, G.; Genovese Ebert, F.

    1988-01-01

    The authors emphasize the usefulness of digital dacrycystography (DCG), as compared with various current technoques. Utilizing a radiographic unit equipped with a video-fluoroscopic system and interfaced to a digital video-processor, several digitalized images are acquired before, during and after the injection of contrast medium. Final images are obtained by subtraction of suitable pairs of source frames. Twenty-six patients affected by epiphora have been examined so far. In 21 cases digital subtraction DCG allowed an accurate visualization of the lacrimal system; in the other five patients the amount of information was acceptable. This methodology allows the assessment of both the normal anatomy of the lacrimal passages and their pathological patterns, such as obstructions, stenoses, fistulas, chronic dacrycystites, lacrimal stones. The examination is easy and quick to perform, with no discomfort for the patient. Digital subtraction DCG proves thus to be a very valuable technique thanks to its possible electronic elaboration - i.e. the subtraction and the magnification of images - to its better contrast resolution, and to the possibility it yields of dynamic studies under radioscopic control

  16. Evaluation of computed radiography (CR) and digital radiography (DR) image quality against the EUREF guidelines

    International Nuclear Information System (INIS)

    Honey, I.

    2007-01-01

    Full text: In the UK National Health Service Breast Screening Program (NHSBSP) the predominant imaging technique remains film/screen. However there is a gradual move towards digital imaging technologies. Before a system can be considered for use by the NHSBSP it must undergo technical and clinical evaluation. The technical evaluation must meet the requirements of EUREF1. In this work the image quality of several systems is compared against these guidelines.

  17. Multiline digital radiographic imager study with synchronization to detector gas ion drift

    International Nuclear Information System (INIS)

    Peyret, O.

    1985-01-01

    This direct digital radiographic imager is based on X-ray detection in high pressure rare gas ionization chamber. This linear multidetector, from which scanning radiography is realized, records many lines together. Spatial resolution performance in scanning direction are made sure by scanning synchronization with ion drift in detector. After a physical study and a potential evaluation of its performances on mock-up, a 128 cell prototype has been realized. The first images give validation and limits of such a radiographic process [fr

  18. Radiation dose reduction in the evaluation of scoliosis: an application of digital radiography

    International Nuclear Information System (INIS)

    Kushner, D.C.; Cleveland, R.H.; Herman, T.E.; Zaleske, D.J.; Ehrlich, M.G.; Correia, J.A.

    1986-01-01

    This report documents the clinical testing of scanning beam digital radiography as an imaging method in patients with scoliosis. This type of digital imaging requires a skin exposure of only 2.4 mR (0.619 microC/kg) per image, compared with the lowest possible posteroanterior screen-film exposure of 10 mR (2.58 microC/kg) at the chest and 60 mR (15.48 microC/kg) at the lumbar spine. Digital radiographic and screen-film images were obtained on multiple test objects and 273 patients. Scoliosis measurements using screen-film radiographs and digital radiographs were comparable to within a mean difference of 1 degrees at many different degrees of severity. The low-dose digital images were found to be useful and accurate for the detection and measurement of scoliosis after the first screen-film radiographs have excluded tumors and structural abnormalities

  19. Endodontic radiography: who is reading the digital radiograph?

    Science.gov (United States)

    Tewary, Shalini; Luzzo, Joseph; Hartwell, Gary

    2011-07-01

    Digital radiographic imaging systems have undergone tremendous improvements since their introduction. Advantages of digital radiographs over conventional films include lower radiation doses compared with conventional films, instantaneous images, archiving and sharing images easily, and manipulation of several radiographic properties that might help in diagnosis. A total of 6 observers including 2 endodontic residents, 3 endodontists, and 1 oral radiologist evaluated 150 molar digital periapical radiographs to determine which of the following conditions existed: normal periapical tissue, widened periodontal ligament, or presence of periapical radiolucency. The evaluators had full control over the radiograph's parameters of the Planmeca Dimaxis software program. All images were viewed on the same computer monitor with ideal vie-wing conditions. The same 6 observers evaluated the same 150 digital images 3 months later. The data were analyzed to determine how well the evaluators agreed with each other (interobserver agreement) for 2 rounds of observations and with themselves (intraobserver agreement). Fleiss kappa statistical analysis was used to measure the level of agreement among multiple raters. The overall Fleiss kappa value for interobserver agreement for the first round of interpretation was 0.34 (P value for interobserver agreement for the second round of interpretation was 0.35 (P fair (0.2-0.4) agreement among the 6 raters at both observation periods. A weighted kappa analysis was used to determine intraobserver agreement, which showed on average a moderate agreement. The results indicate that the interpretation of a dental radiograph is subjective, irrespective of whether conventional or digital radiographs are used. The factors that appeared to have the most impact were the years of experience of the examiner and familiarity of the operator with a given digital system. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All

  20. Digital radiography with computerized conventional monitors compared to medical monitors in vertical root fracture diagnosis.

    Science.gov (United States)

    Tofangchiha, Maryam; Adel, Mamak; Bakhshi, Mahin; Esfehani, Mahsa; Nazeman, Pantea; Ghorbani Elizeyi, Mojgan; Javadi, Amir

    2013-01-01

    Vertical root fracture (VRF) is a complication which is chiefly diagnosed radiographically. Recently, film-based radiography has been substituted with digital radiography. At the moment, there is a wide range of monitors available in the market for viewing digital images. The present study aims to compare the diagnostic accuracy, sensitivity and specificity of medical and conventional monitors in detection of vertical root fractures. In this in vitro study 228 extracted single-rooted human teeth were endodontically treated. Vertical root fractures were induced in 114 samples. The teeth were imaged by a digital charge-coupled device radiography using parallel technique. The images were evaluated by a radiologist and an endodontist on two medical and conventional liquid-crystal display (LCD) monitors twice. Z-test was used to analyze the sensitivity, accuracy and specificity of each monitor. Significance level was set at 0.05. Inter and intra observer agreements were calculated by Cohen's kappa. Accuracy, specificity and sensitivity for conventional monitor were calculated as 67.5%, 72%, 62.5% respectively; and data for medical grade monitor were 67.5%, 66.5% and 68% respectively. Statistical analysis showed no significant differences in detecting VRF between the two techniques. Inter-observer agreement for conventional and medical monitor was 0.47 and 0.55 respectively (moderate). Intra-observer agreement was 0.78 for medical monitor and 0.87 for conventional one (substantial). The type of monitor does not influence diagnosis of vertical root fractures.

  1. Enhancement of digital radiography image quality using a convolutional neural network.

    Science.gov (United States)

    Sun, Yuewen; Li, Litao; Cong, Peng; Wang, Zhentao; Guo, Xiaojing

    2017-01-01

    Digital radiography system is widely used for noninvasive security check and medical imaging examination. However, the system has a limitation of lower image quality in spatial resolution and signal to noise ratio. In this study, we explored whether the image quality acquired by the digital radiography system can be improved with a modified convolutional neural network to generate high-resolution images with reduced noise from the original low-quality images. The experiment evaluated on a test dataset, which contains 5 X-ray images, showed that the proposed method outperformed the traditional methods (i.e., bicubic interpolation and 3D block-matching approach) as measured by peak signal to noise ratio (PSNR) about 1.3 dB while kept highly efficient processing time within one second. Experimental results demonstrated that a residual to residual (RTR) convolutional neural network remarkably improved the image quality of object structural details by increasing the image resolution and reducing image noise. Thus, this study indicated that applying this RTR convolutional neural network system was useful to improve image quality acquired by the digital radiography system.

  2. Comparison of ultrasound, digital, and conventional radiography in differentiating periapical lesions: An in vivo study

    Directory of Open Access Journals (Sweden)

    Purnachandrarao Naik Nunsavathu

    2015-01-01

    Full Text Available Aims and Objectives: To evaluate in vivo the efficacy of ultrasound, digital and conventional radiography in identifying periapical lesions. To compare the results of the above imaging modalities with histopathology, which is considered to be the gold standard for diagnosis. Materials and Methods: Thirty patients aged between 15 and 45 years with periapical lesions associated with maxillary or mandibular anterior teeth indicated for endodontic surgery or extraction were selected for the study. Pre-operatively, conventional, digital periapical radiography and ultrasonography were done and interpreted. Endodontic surgery or extraction was performed including curettage of apical tissue to enable histopathological investigation, which provided the gold standard diagnosis. All measurements and findings were compared and statistically analyzed. Results: In conventional and digital radiography, the periapical lesions were readily identified but observers were unable to differentiate granuloma from cyst using these modalities only. But ultrasonography was able to give the true nature of the periapical pathology. All the cases diagnosed by ultrasound were confirmed with histopathology, and maximal number of cases diagnosed by ultrasound correlated with the histopathological diagnosis. Conclusion: The present study confirms that ultrasound is a promising and reliable imaging technique for differentiating periapical lesions i.e., periapical cysts and granulomas. Based on the echo texture of their contents and the presence of vascularity using color Doppler, periapical cyst and granulomas can be readily identified. The present study is further applicable for the evaluation of periapical lesions of the posterior teeth and evaluation of other jaw lesions.

  3. Neutron radiography

    International Nuclear Information System (INIS)

    Alaa eldin, M.T.

    2011-01-01

    The digital processing of the neutron radiography images gives the possibility for data quantification. In this case an exact relation between the measured neutron attenuation and the real macroscopic attenuation coefficient for every point of the sample is required. The assumption that the attenuation of the neutron beam through the sample is exponential is valid only in an ideal case where a monochromatic beam, non scattering sample and non background contribution are assumed. In the real case these conditions are not fulfilled and in dependence on the sample material we have more or less deviation from the exponential attenuation law. Because of the high scattering cross-sections of hydrogen (σs=80.26 barn) for thermal neutrons, the problem with the scattered neutrons at quantitative radiography investigations of hydrogenous materials (as PE, Oil, H 2 O, etc) is not trivial. For these strong scattering materials the neutron beam attenuation is no longer exponential and a dependence of the macroscopic attenuation coefficient on the material thickness and on the distance between the sample and the detector appears. When quantitative radiography (2 D) or tomography investigations (3 D) are performed, some image correction procedures for a description of the scattering effect are required. This thesis presents a method that can be used to enhance the neutron radiography image for objects with high scattering materials like hydrogen, carbon and other light materials. This method uses the Monte Carlo code, MCNP5, to simulate the neutron radiography process and get the flux distribution for each pixel of the image and determine the scattered neutrons distribution that causes the image blur and then subtract it from the initial image to improve its quality.

  4. Digital autoradiography using silicon strip detectors

    Energy Technology Data Exchange (ETDEWEB)

    Overdick, M.

    1998-05-01

    Spatially resolving radiation detection systems operating in real time can be used to acquire autoradiographic images. An overview over alternatives to traditional autoradiography is given and the special features of these filmless methods are discussed. On this basis the design of a system for digital autoradiography using silicon strip detectors is presented. Special emphasis is put on the physical background of the detection process in the semiconductor and on the self-triggering read-out technique. The practical performance of the system is analyzed with respect to energy and spatial resolution. This analysis is complemented by case studies from cell biology (especially electrophoresis), botany and mineralogy. Also the results from a time-resolved autoradiographic experiment are presented. (orig.) 80 refs.

  5. Digital radiography using the individual photon counting technique

    International Nuclear Information System (INIS)

    Bellazzini, R.; Brez, A.; Del Guerra, A.; Massai, M.M.; Torquati, M.R.

    1987-01-01

    A MultiWire Proportional Chamber (MWPC) is a poissonian, electronic, area detector and for this reason since its introduction it has received great attention for its possible application in the biomedical field. To be suitable for medical imaging a MWPC should satisfy the following stringent requirements: 1) good detection efficiency; 2) good spatial resolution; 3) high-rate capability. The authors describe a system which shows promise for biomedical imaging applications. (Auth.)

  6. Digital image processing for real-time neutron radiography and its applications

    International Nuclear Information System (INIS)

    Fujine, Shigenori

    1989-01-01

    The present paper describes several digital image processing approaches for the real-time neutron radiography (neutron television-NTV), such as image integration, adaptive smoothing and image enhancement, which have beneficial effects on image improvements, and also describes how to use these techniques for applications. Details invisible in direct images of NTV are able to be revealed by digital image processing, such as reversed image, gray level correction, gray scale transformation, contoured image, subtraction technique, pseudo color display and so on. For real-time application a contouring operation and an averaging approach can also be utilized effectively. (author)

  7. Test experiments on muon radiography with emulsion track detectors in Russia

    International Nuclear Information System (INIS)

    Aleksandrov, A.B.; Bagulya, A.V.; Vladimirov, M.S.

    2015-01-01

    The Lebedev Physical Institute of the Russian Academy of Sciences (FIAN) and the Skobeltsyn Institute of Nuclear Physics of the Lomonosov Moscow State University (SINP MSU) opened in Russia a series of pilot muon radiography experiments with nuclear emulsion detectors for study of interior structure of large-scale natural and industrial objects. As a result the optimal conditions of experiment organization were determined, algorithms of data processing were worked out and peculiarities of the method were ultimately investigated. The experiment data, including field observations (in the mine of the Geophysical Department of the Russian Academy of Sciences), were also presented which confirm that the method with track detectors on the base of nuclear emulsions with uniquely high spatial resolution holds much promise in case of their high-tech automated processing

  8. Neural network scatter correction technique for digital radiography

    International Nuclear Information System (INIS)

    Boone, J.M.

    1990-01-01

    This paper presents a scatter correction technique based on artificial neural networks. The technique utilizes the acquisition of a conventional digital radiographic image, coupled with the acquisition of a multiple pencil beam (micro-aperture) digital image. Image subtraction results in a sparsely sampled estimate of the scatter component in the image. The neural network is trained to develop a causal relationship between image data on the low-pass filtered open field image and the sparsely sampled scatter image, and then the trained network is used to correct the entire image (pixel by pixel) in a manner which is operationally similar to but potentially more powerful than convolution. The technique is described and is illustrated using clinical primary component images combined with scatter component images that are realistically simulated using the results from previously reported Monte Carlo investigations. The results indicate that an accurate scatter correction can be realized using this technique

  9. Digital image processing in NDT : Application to industrial radiography

    International Nuclear Information System (INIS)

    Aguirre, J.; Gonzales, C.; Pereira, D.

    1988-01-01

    Digital image processing techniques are applied to image enhancement discontinuity detection and characterization is radiographic test. Processing is performed mainly by image histogram modification, edge enhancement, texture and user interactive segmentation. Implementation was achieved in a microcomputer with video image capture system. Results are compared with those obtained through more specialized equipment main frame computers and high precision mechanical scanning digitisers. Procedures are intended as a precious stage for automatic defect detection

  10. Detection of on-surface objects with an underground radiography detector system using cosmic-ray muons

    Science.gov (United States)

    Fujii, Hirofumi; Hara, Kazuhiko; Hayashi, Kohei; Kakuno, Hidekazu; Kodama, Hideyo; Nagamine, Kanetada; Sato, Kazuyuki; Sato, Kotaro; Kim, Shin-Hong; Suzuki, Atsuto; Takahashi, Kazuki; Takasaki, Fumihiko

    2017-05-01

    We have developed a compact muon radiography detector to investigate the status of the nuclear debris in the Fukushima Daiichi Reactors. Our previous observation showed that a large portion of the Unit-1 Reactor fuel had fallen to floor level. The detector must be located underground to further investigate the status of the fallen debris. To investigate the performance of muon radiography in such a situation, we observed 2 m cubic iron blocks located on the surface of the ground through different lengths of ground soil. The iron blocks were imaged and their corresponding iron density was derived successfully.

  11. Removing Distortion of Periapical Radiographs in Dental Digital Radiography Using Embedded Markers in an External frame.

    Science.gov (United States)

    Kafieh, Rahele; Shahamoradi, Mahdi; Hekmatian, Ehsan; Foroohandeh, Mehrdad; Emamidoost, Mostafa

    2012-10-01

    To carry out in vivo and in vitro comparative pilot study to evaluate the preciseness of a newly proposed digital dental radiography setup. This setup was based on markers placed on an external frame to eliminate the measurement errors due to incorrect geometry in relative positioning of cone, teeth and the sensor. Five patients with previous panoramic images were selected to undergo the proposed periapical digital imaging for in vivo phase. For in vitro phase, 40 extracted teeth were replanted in dry mandibular sockets and periapical digital images were prepared. The standard reference for real scales of the teeth were obtained through extracted teeth measurements for in vitro application and were calculated through panoramic imaging for in vivo phases. The proposed image processing thechnique was applied on periapical digital images to distinguish the incorrect geometry. The recognized error was inversely applied on the image and the modified images were compared to the correct values. The measurement findings after the distortion removal were compared to our gold standards (results of panoramic imaging or measurements from extracted teeth) and showed the accuracy of 96.45% through in vivo examinations and 96.0% through in vitro tests. The proposed distortion removal method is perfectly able to identify the possible inaccurate geometry during image acquisition and is capable of applying the inverse transform to the distorted radiograph to obtain the correctly modified image. This can be really helpful in applications like root canal therapy, implant surgical procedures and digital subtraction radiography, which are essentially dependent on precise measurements.

  12. Evaluation of the detector response function digital conventional radiology

    International Nuclear Information System (INIS)

    Arino Gil, A.; Hernandez Rodriguez, J.; Mateos Salvador, P.; Rodriguez Lopez, B.; Font Gelabert, J. C.

    2013-01-01

    The objective of this work is to obtain the response function that relates the air kerma at the entrance of the detector and pixel value, for a series of digital detectors of conventional Radiology model Optimus DigitalDiagnost Philips () and 6000 Definium General Electric. From the set of measurements is obtained a response function for each reference type of detector, and compared with those published in the literature for these teams. (Author)

  13. Accuracy of digital subtraction radiography in combination with a contrast media in assessment of proximal caries depth

    Directory of Open Access Journals (Sweden)

    Farzad Esmaeili

    2008-07-01

    Full Text Available Background and aims. Radiography is used to diagnose the demineralization process and carious lesions; however, conventional radiography and direct digital images do not show these lesions when the amount of demineralization is less than 40%. Digital subtraction radiography has recently been used to improve the diagnostic quality of these lesions. The purpose of this study was to compare the caries depth estimated by digital subtraction radiography in combination with barium sulfate in diagnosing proximal dental caries with histopathologic evaluation. Materials and methods. In this study 30 molars and premolars (24 demineralized lesions with cavity, 8 without cavity were studied. Direct digital images were taken (kVp: 68, mA: 8; t: 0.12 for premolars and t: 0.16 for molars whereas the position of X-ray tube and CCD receptor and teeth was fixed. To prepare the second images 135 gr/L barium sulfate was used. The images obtained with the same exposure and geometry and then subtracted. The depth of the lesions in direct digital and subtracted images were assessed and compared with the depth measured in histopathologic assessments. Results. The mean depths (± SD of the lesions were 1.80 ± 0.77 mm in direct digital radiography, 2.32 ± 0.76 mm in subtracted images after barium sulfate treatment, and 2.51 ± 0.43 mm in histopathologic sections. The statistical difference between direct digital radiography and the other methods was significant (P < 0.05. However, the differences were not statistically significant between subtracted images and histopathologic sections. The average intra-class correlation coefficient was 0.7241 (CI: 95%. Conclusion. The present study has demonstrated that digital subtraction radiography images have the potential to measure the depth of proximal caries with no significant difference with histopathologic evaluation.

  14. A comparison of digital tomosynthesis and chest radiography in evaluating airway lesions using computed tomography as a reference.

    Science.gov (United States)

    Choo, Ji Yung; Lee, Ki Yeol; Yu, Ami; Kim, Je-Hyeong; Lee, Seung Heon; Choi, Jung Won; Kang, Eun-Young; Oh, Yu Whan

    2016-09-01

    To compare the diagnostic performance of digital tomosynthesis (DTS) and chest radiography for detecting airway abnormalities, using computed tomography (CT) as a reference. We evaluated 161 data sets from 149 patients (91 with and 70 without airway abnormalities) who had undergone radiography, DTS, and CT to detect airway problems. Radiographs and DTS were evaluated to localize and score the severity of the airway abnormalities, and to score the image quality using CT as a reference. Receiver operating characteristics (ROC), McNemar's test, weighted kappa, and the paired t-test were used for statistical analysis. The sensitivity of DTS was higher (reader 1, 93.51 %; reader 2, 94.29 %) than chest radiography (68.83 %; 71.43 %) in detecting airway lesions. The diagnostic accuracy of DTS (90.91 %; 94.70 %) was also significantly better than that of radiography (78.03 %; 82.58 %, all p chest radiography (1.83, 2.74; p < 0.05) in the results of both readers. The inter-observer agreement with respect to DTS findings was moderate and superior when compared to radiography findings. DTS is a more accurate and sensitive modality than radiography for detecting airway lesions that are easily obscured by soft tissue structures in the mediastinum. • Digital tomosynthesis offers new diagnostic options for airway lesions. • Digital tomosynthesis is more sensitive and accurate than radiography for airway lesions. • Digital tomosynthesis shows better image quality than radiography. • Assessment of lesion severity, via tomosynthesis is comparable to computed tomography.

  15. Use of semiconductor detector c-Si microstrip type in obtaining the digital radiographic imaging of phantoms and biological samples of mammary glands

    International Nuclear Information System (INIS)

    Leyva, A.; Cabal, A.; Pinera, I.; Abreu, Y.; Cruz, C. M.; Montano, L. M.; Diaz, C. C.; Fontaine, M.; Ortiz, C. M.; Padilla, F.; De la Mora, R.

    2009-01-01

    The present work synthesizes the experimental results obtained in the characterization of 64 micro strips crystalline silicon detector designed for experiments in high energies physics, with the objective of studying its possible application in advanced medical radiography, specifically in digital mammography and angiography. The research includes the acquisition of two-dimensional radiography of a mammography phantom using the scanning method, and its comparison with similar images simulated mathematically for different X rays sources. The paper also shows the experimental radiography of two biological samples taken from biopsies of mammas, where it is possible to identify the presence of possible pathological lesions. The results reached in this work point positively toward the effective possibility of satisfactorily introducing those advanced detectors in medical digital imaging applications. (Author)

  16. [Optimization of digital chest radiography image post-processing in diagnosis of pneumoconiosis].

    Science.gov (United States)

    Sheng, Bing-yong; Mao, Ling; Zhou, Shao-wei; Shi, Jin

    2013-11-01

    To establish the optimal image post-processing parameters for digital chest radiography as preliminary research for introducing digital radiography (DR) to pneumoconiosis diagnosis in China. A total of 204 pneumoconiosis patients and 31 dust-exposed workers were enrolled as the subjects in this research. Film-screen radiography (FSR) and DR images were taken for all subjects. DR films were printed after raw images were processed and parameters were altered using DR workstation (GE Healthcare, U.S.A.). Image gradations, lung textures, and the imaging of thoracic vertebra were evaluated by pneumoconiosis experts, and the optimal post-processing parameters were selected. Optical density was measured for both DR films and FSR films. For the DR machine used in this research, the contrast adjustment (CA) and brightness adjustment (BA) were the main parameters that determine the brightness and gray levels of images. The optimal ranges for CA and BA were 115%∼120% and 160%∼165%, respectively. The quality of DR chest films would be optimized when tissue contrast was adjusted to a maximum of 0.15, edge to a minimum of 1, and both noise reduction and tissue equalization to0.The failure rate of chest DR (0.4%) was significantly lower than that of chest FSR (17%) (P image post-processing on DR machine purchased from GE Healthcare, the DR chest films can meet all requirements for the quality of chest X-ray films in the Chinese diagnostic criteria for pneumoconiosis.

  17. A dynamic material discrimination algorithm for dual MV energy X-ray digital radiography

    International Nuclear Information System (INIS)

    Li, Liang; Li, Ruizhe; Zhang, Siyuan; Zhao, Tiao; Chen, Zhiqiang

    2016-01-01

    Dual-energy X-ray radiography has become a well-established technique in medical, industrial, and security applications, because of its material or tissue discrimination capability. The main difficulty of this technique is dealing with the materials overlapping problem. When there are two or more materials along the X-ray beam path, its material discrimination performance will be affected. In order to solve this problem, a new dynamic material discrimination algorithm is proposed for dual-energy X-ray digital radiography, which can also be extended to multi-energy X-ray situations. The algorithm has three steps: α-curve-based pre-classification, decomposition of overlapped materials, and the final material recognition. The key of the algorithm is to establish a dual-energy radiograph database of both pure basis materials and pair combinations of them. After the pre-classification results, original dual-energy projections of overlapped materials can be dynamically decomposed into two sets of dual-energy radiographs of each pure material by the algorithm. Thus, more accurate discrimination results can be provided even with the existence of the overlapping problem. Both numerical and experimental results that prove the validity and effectiveness of the algorithm are presented. - Highlights: • A material discrimination algorithm for dual MV energy X-ray digital radiography is proposed. • To solve the materials overlapping problem of the current dual energy algorithm. • The experimental results with the 4/7 MV container inspection system are shown.

  18. Detection of rib fractures in an abused infant using digital radiography: a laboratory study

    International Nuclear Information System (INIS)

    Kleinman, Paul K.; O'Connor, Brian; Nimkin, Katherine; Rayder, Shawn M.; Spevak, Melissa R.; Belanger, Patricia L.; Getty, David J.; Karellas, Andrew

    2002-01-01

    To assess the diagnostic performance of digital radiography using charge-coupled device (CCD) technology in the detection of rib fracture in infant abuse.Materials and methods. Four fractured posterior rib arcs and eight normal ribs removed at autopsy from a 10-month-old abused infant were radiographed using a CCD prototype, four clinical film-screen systems, and direct-exposure film. Each rib was viewed with these six systems in nine different projections. The resultant 648 images were assessed for probability of fracture (0-100%) by four pediatric radiologists. The calculated area under the resultant ROC curves (A z ) for the CCD was compared with those obtained with direct-exposure, high-detail, medium and fast film-screen radiographic systems. The mean A z for the CCD (0.937) fell within the range of the high-detail systems (0.934-0.940) and was significantly higher (p 20 line pairs per millimeter) the CCD performance was comparable (A z =0.944 vs. 0.937). The similar performance can be explained by the higher contrast resolution of the digital technology. This study indicates that in the ex vivo setting, digital radiology can perform comparably to high-detail film-screen imaging. The findings suggest that digital radiography has the potential to replace film-screen imaging in the evaluation of inflicted skeletal injury in infants. (orig.)

  19. A study on the artificial interproximal caries detection with the digital radiography

    International Nuclear Information System (INIS)

    Kwon, Ki Jeong; Hwang, Eui Hwan; Lee, Sang Rae

    1994-01-01

    The purposes of this study were clinical comparison and evaluation between digital radiography and conventional radiography for the detection of artificial interproximal caries. Four freshly extracted, unrestored posterior teeth were obtained and caries was simulated by drilling semicircled defects with variable size at the interproximal surface of each tooth. The experiments were performed with IBM-PC/32 bit -DX compatible, video camera (VM-S8200, Hitachi Co., Japan), and color monitor (Multisync 3D, NEC, Japan). Sylvia Image Capture Board for the ADC (analog to digital converter) was used, and spatial resolution has 256 gray levels. The obtained results were as follows: 1. at the condition of under exposure, the radiographs were superior to the images in readability. Also, as the size of the artificial lesion was increased, readability of the radiographs was elevated. 2. The digital images were superior to the radiographs in readability especially under over exposure. 3. As the exposure time and size of lesion was increased, the gray level of region of interest of the digital image was decreased proportionally. 4. As the F-value of average gray level of region of individual exposure time and size of lesion, gray level of the all lesion sizes was decreased in comparison with the normal enamel.

  20. A Study on the Exposure Parameter and the Patient Dose for Digital Radiography System in Daegoo

    International Nuclear Information System (INIS)

    Jo, Gwang Ho; Kang, Yeopng Han; Kim, Bu Sun

    2008-01-01

    Digital imaging for general radiography has many advantages over the film/screen systems, including a wider dynamic range and the ability to manipulate the images produced. The wider range means that acceptable images may by acquired at a range of dose levels, and therefore repeat exposures can be reduced. Digital imaging can result in the over use of radiation, however, because there is a tendency can be reduced. Digital imaging can result in the over use of radiation, however, because there is a tendency for images to be acquired at too high a dose. We investigated the actual exposure dose conditions on general radiography and a questionnaire survey was conducted with radiotechnologiest at medical institutions using digital radiology system. As a results, the dose of exposure was not controlled with patient's figure and dose optimization but was controlled by worker's convenience and image quality. Radio-technologiests often set up the exposure dose regardless of patient figure and body part to be examined. Many organizations, such as the International Commission on Radiological Protection, recommend to keep the dose as low as possible. In addition, they strongly recommend to keep the optimal but minimal dosage by proper training programs and constant quality control, including frequent patient dose evaluations and education.

  1. Digital radiography - from principles to practical testing; Digitale Radiografie - von den Grundlagen zur Pruefpraxis

    Energy Technology Data Exchange (ETDEWEB)

    Mattis, A. [Siemens KWU, Erlangen (Germany)

    1994-12-31

    Digital radiography is broken down into two branches: storage luminescence technology and digitalization of existing films. The principles of both methods are presented in a short outline. The main advantages of this technology include decay-proof archiving that dispenses with film storage, computerized analysis of images using quantitative assessment standards, and improved display readability as compared to visual analysis. As a neutral authority, the Federal Institute for Materials Research and Testing (BAM) was charged with making an assessment of digital radiography by means of the approved ROC method. Based on an extensive collection of test pieces, the respective final result of the analysis was compared with the transmission images, i.e. digital data were compared with original films. (orig./MM) [Deutsch] Die Digitale Radiografie teilt sich in zwei Zweige - die Speicherleuchtstofftechnik sowie die Digitalisierung vorhandener Filme. Die Prinzipien beider Verfahren werden in einem kurzen Abriss dargestellt. Hauptvorteile dieser Technik sind die verfallsgesicherte Archivierung, die die Aufbewahrung der Filme ueberfluessig macht, die rechnergestuetzte Analyse der Aufnahmen unter Einsatz quantitativer Beurteilungsmassstaebe sowie die verbesserte Anzeigenerkennbarkeit gegenueber der visuellen Auswertung. Als neutrale Instanz wurde die Bundesanstalt fuer Materialforschung (BAM) beauftragt, mithilfe des anerkannten ROC-Verfahrens die Digitale Radiografie zu beurteilen. Basierend auf einer umfangreichen Sammlung von Teststuecken wurde das jeweilige Endergebnis der Auswertung der Durchstrahlungsaufnahmen verglichen d.h. digitale Daten mit Original-Filmen. (orig./MM)

  2. An ROC study detecting ability of idiopathic pulmonary fibrosis using digital radiography

    International Nuclear Information System (INIS)

    Chung, Eun Chul; Im, Jung Gi; Han, Man Chung; Kim, Jong Hyo

    1991-01-01

    One potential advantage of the digital radiography system is its ability to enhance image quality by various types of processing. Digital unsharp masking is one of the simplest and most useful forms of enhancing processes. The efficacy of unsharp masking in radiological diagnosis has not been investigated thoroughly. To evaluate the effects of unsharp masking in film-digital chest images, 3 observers were shown 150 test radiographs. These test radiographs consisted of 50 unprocessed images (25 normals and 25 patients with idiopathic pulmonary fibrosis with honey combing) and their 100 processed images by using 450 and 15-sized masks respectively. An ROC analysis of these data suggests that unsharp masking is more effective in detecting idiopathic pulmonary fibrosis than unprocessed image (ρ < 0.05), and so it may improve diagnostic accuracy for interstitial fibrosis. In addition, the smaller mask size (15) is more effective than the larger one (mask size 45) (ρ < 0.05). By using this analytic approach, an optimal parameter in digital chest radiography may be investigated in many other forms of pulmonary disease such as pulmonary nodule or mediastinal mass

  3. An ROC study detecting ability of idiopathic pulmonary fibrosis using digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Eun Chul; Im, Jung Gi; Han, Man Chung; Kim, Jong Hyo [College of Medicine, Ewha Womens University, Seoul (Korea, Republic of)

    1991-03-15

    One potential advantage of the digital radiography system is its ability to enhance image quality by various types of processing. Digital unsharp masking is one of the simplest and most useful forms of enhancing processes. The efficacy of unsharp masking in radiological diagnosis has not been investigated thoroughly. To evaluate the effects of unsharp masking in film-digital chest images, 3 observers were shown 150 test radiographs. These test radiographs consisted of 50 unprocessed images (25 normals and 25 patients with idiopathic pulmonary fibrosis with honey combing) and their 100 processed images by using 450 and 15-sized masks respectively. An ROC analysis of these data suggests that unsharp masking is more effective in detecting idiopathic pulmonary fibrosis than unprocessed image ({rho} < 0.05), and so it may improve diagnostic accuracy for interstitial fibrosis. In addition, the smaller mask size (15) is more effective than the larger one (mask size 45) ({rho} < 0.05). By using this analytic approach, an optimal parameter in digital chest radiography may be investigated in many other forms of pulmonary disease such as pulmonary nodule or mediastinal mass.

  4. Automatic anatomically selective image enhancement in digital chest radiography

    International Nuclear Information System (INIS)

    Sezan, M.I.; Minerbo, G.N.; Schaetzing, R.

    1989-01-01

    The authors develop a technique for automatic anatomically selective enhancement of digital chest radiographs. Anatomically selective enhancement is motivated by the desire to simultaneously meet the different enhancement requirements of the lung field and the mediastinum. A recent peak detection algorithm and a set of rules are applied to the image histogram to determine automatically a gray-level threshold between the lung field and mediastinum. The gray-level threshold facilitates anatomically selective gray-scale modification and/or unsharp masking. Further, in an attempt to suppress possible white-band or black-band artifacts due to unsharp masking at sharp edges, local-contrast adaptivity is incorporated into anatomically selective unsharp masking by designing an anatomy-sensitive emphasis parameter which varies asymmetrically with positive and negative values of the local image contrast

  5. X-ray imaging using amorphous selenium: photoinduced discharge (PID) readout for digital general radiography.

    Science.gov (United States)

    Rowlands, J A; Hunter, D M

    1995-12-01

    Digital radiographic systems based on photoconductive layers with the latent charge image readout by photoinduced discharge (PID) are investigated theoretically. Previously, a number of different systems have been proposed using sandwiched photoconductor and insulator layers and readout using a scanning laser beam. These systems are shown to have the general property of being very closely coupled (i.e., optimization of one imaging characteristic usually impacts negatively on others). The presence of a condensed state insulator between the photoconductor surface and the readout electrode does, however, confer a great advantage over systems using air gaps with their relatively low breakdown field. The greater breakdown field of condensed state dielectrics permits the modification of the electric field during the period between image formation and image readout. The trade-off between readout speed and noise makes this system suitable for instant general radiography and even rapid sequence radiography, however, the system is unsuitable for the low exposure rates used in fluoroscopy.

  6. X-ray image intensifier/television systems for digital skeletal radiography

    International Nuclear Information System (INIS)

    Rowlands, J.A.; Hynes, D.M.; Edmonds, E.W.; Porter, A.J.; Toth, B.J.

    1987-01-01

    The imaging criteria for skeletal radiography (high resolution and low noise) relevant to the use of x-ray image intensifier/TV digital systems are discussed. It is shown from the modulation transfer function (MTF), noise, and phantom evaluations that conventional x-ray image intensifiers in conjunction with a 1,000-line Plumbicon or Saticon TV camera are in most respects suitable for skeletal radiography. The optimum focal spot size depends on a trade-off with motion blurring through the x-ray exposure time and so is a function of the clinical problem. Since the skeletal system is readily immobilized, a 0.3-mm focal spot size is nearly optimum

  7. Quality assurance in digital dental radiography--justification and dose reduction in dental and maxillofacial radiology.

    Science.gov (United States)

    Hellstern, F; Geibel, M-A

    2012-01-01

    To evaluate the implementation of quality assurance requirements for digital dental radiography in routine clinical practice. The results should be discussed by radiation protection authorities in the context of the relevant legal requirements and current debates on radiation protection. Two hundred digital dental radiographs were randomly selected from the digital database of the Department of Dentistry's Dental and Maxillofacial Surgery Clinic, Ulm University, and evaluated for various aspects of image quality and compliance with radiographic documentation requirements. The dental films were prepared by different radiology assistants (RAs) using one of two digital intraoral radiographic systems: Sirona Heliodent DS, 60 kV, focal spot size: 0.7 mm (group A) or KaVo Gendex 765 DC, 65 kV, focal spot size: 0.4 mm (group B). Radiographic justification was documented in 70.5% of cases, and the radiographic findings in 76.5%. Both variables were documented in the patient records as well as in the software in 14% of cases. Clinical documentation of the required information (name of the responsible dentist and radiology assistant, date, patient name, department, tube voltage, tube current, exposure time, type of radiograph, film size, department and serial number of the dental radiograph) was 100% complete in all cases. Moreover, the department certified according to DIN ISO 9001:2008 specifications demonstrated complete clinical documentation of radiographic justifications and radiographic findings. The entire dentition was visible on 83% of the digital films. The visible area corresponded to the target region on 85.7% of the digital dental radiographs. Seven to 8.5% of the images were classified as "hypometric" or "hypermetric". This study indicates that improvements in radiology training and continuing education fordentists and dental staff performing x-ray examinations are needed to ensure consistent high quality of digital dental radiography. Implementation of

  8. Technical characterization of five x-ray detectors for paediatric radiography applications

    Science.gov (United States)

    Marshall, N. W.; Smet, M.; Hofmans, M.; Pauwels, H.; De Clercq, T.; Bosmans, H.

    2017-12-01

    Physical image quality of five x-ray detectors used in the paediatric imaging department is characterized with the aim of establishing the range/scope of imaging performance provided by these detectors for neonatal imaging. Two computed radiography (CR) detectors (MD4.0 powder imaging plate (PIP) and HD5.0 needle imaging plate (NIP), Agfa HealthCare NV, B-2640 Mortsel, Belgium) and three flat panel detectors (FPD) (the Agfa DX-D35C and DX-D45C and the DRX-2530C (Carestream Health Inc., Rochester, NY 14608, USA)) were assessed. Physical image quality was characterized using the detector metrics given by the International Electrotechnical Commission (IEC 62220-1) to measure modulation transfer function (MTF), the noise power spectrum (NPS) and the detective quantum efficiency (DQE) using the IEC-specified beam qualities of RQA3 and RQA5. The DQE was evaluated at the normal operating detector air kerma (DAK) level, defined at 2.5 µGy for all detectors, and at factors of 1/3.2 and 3.2 times the normal level. MTF curves for the different detectors were similar at both RQA3 and RQA5 energies; the average spatial frequency for the 50% point (MTF0.5) at RQA3 was 1.26 mm-1, with a range from 1.20 mm-1 to 1.37 mm-1. The DQE of the NIP CR compared to the PIP CR was notably greater and similar to that for the FPD devices. At RQA3, average DQE for the FPD and NIP (at 0.5 mm-1 2.5 µGy) was 0.57 compared to 0.26 for the PIP CR. At the RQA5 energy, the DRX-2530C and the DX-D45C had the highest DQE (~0.6 at 0.5 mm-1 2.5 µGy). Noise separation analysis using the polynomial model showed higher electronic noise for the DX-D35C and DRX-2530C detectors; this explains the reduced DQE seen at 0.7 µGy/image. The NIP CR detector offers notably improved DQE performance compared to the PIP CR system and a value similar to the DQE for FPD devices at the RQA3 energy.

  9. A comparison of digital luminescence radiography and conventional film/screen techniques in the diagnosis of fractures

    International Nuclear Information System (INIS)

    Fink, U.; Schwerdtfeger, J.; Fink, B.K.; Schaetzl, M.; Reiser, M.

    1996-01-01

    The accuracy of digital luminescence radiography was compared with that of conventional film/screen techniques, using animal preparations and clinical examinations. Fine fissures were made in 8 animal bones and these were examined radiologically. The digital examinations were carried out with and without edge enhancement. 208 patients were examined in a similar way. Film quality and assessment of the fractures were evaluated quantitatively. In no instance did either of the digital methods provide inferior quality when compared with conventional films. ROC analysis for evaluation of fractures in patients, using an experienced radiologist, showed no significant difference between the various methods (ROC areas: Conventional 0.947, digital 0.958, digital with edge enhancement 0.943). With a less experienced observer there were significant advantages for both digital methods (ROC areas: 0.851, 0.886, 0.908). Our investigation has proved that fractures which are difficult to see can be reliably demonstrated by digital luminescence radiography. (orig.) [de

  10. Future approaches to digital systems

    International Nuclear Information System (INIS)

    Woodrough, R.E.; Beckmann, E.; Jenkins, D.; Belcher, D.

    1984-01-01

    The introduction of the first digital imaging systems has led to the concept of a totally digital imaging department - the 'filmless department'. This concept and its associated network system for digital departments are briefly considered. A transducer system of scanned projection radiography with solid state detectors used in digital chest imaging is described. The principles of this transducer system are applicable to other forms of digital radiography. (U.K.)

  11. A Nuclear Emulsion Detector for the Muon Radiography of a Glacier Structure

    Directory of Open Access Journals (Sweden)

    Akitaka Ariga

    2018-04-01

    Full Text Available Cosmic ray muons can be used to image the interior of geological sites provided that one employs detectors able to operate in the specific harsh conditions of the mountain environment. We designed and developed a detector exploiting the nuclear emulsion technique to assess the bedrock profile underneath an alpine glacier. Nuclear emulsions do not need any electric power supply or maintenance and allow for the measurement of the muon flux and direction behind a large target volume. The 3D density distribution of the material traversed by muons can then be assessed, bringing relevant information on the shape of the boundary between the glacial ice and the underlying bedrock. This new methodology in the geological field was recently tested in a campaign of measurements in the Jungfrau region of the central Swiss Alps. It was shown that the bedrock surface position can be measured with a resolution of about 5 % when the traversed target is about 100 m thick. Characteristics and performance of the method are reported here and demonstrate that muon radiography based on emulsion detectors represents a powerful tool for the geological study of glaciers.

  12. Application of digital radiography for the non-destructive characterization of radioactive waste packages

    International Nuclear Information System (INIS)

    Lierse, C.; Goebel, H.; Kaciniel, E.; Buecherl, T.; Krebs, K.

    1995-01-01

    Digital radiography (DR) using gamma-rays is a powerful tool for the non-destructive determination of various parameters which are relevant within the quality control procedure of radioactive waste packages prior to an interim storage or a final disposal. DR provides information about the waste form and the extent of filling in a typical container. It can identify internal structures and defects, gives their geometric dimensions and helps to detect non-declared inner containers, shielding materials etc. From a digital radiographic image the waste matrix homogeneity may be determined and mean attenuation coefficients as well as density values for selected regions of interest can be calculated. This data provides the basis for an appropriate attenuation correction of gamma emission measurements (gamma scanning) and makes a reliable quantification of gamma emitters in waste containers possible. Information from DR measurements are also used for the selection of interesting height positions of the object which are subsequently inspected in more detail by other non-destructive methods, e. g. by transmission computerized tomography (TCT). The present paper gives important technical specifications of an integrated tomography system (ITS) which is used to perform digital radiography as well as transmission/emission computerized tomography (TCT/ECT) on radioactive waste packages. It describes the DR mode and some of its main applications and shows typical examples of radiographs of real radioactive waste drums

  13. Digital radiography density measurements in differentiation between periapical granulomas and radicular cysts.

    Science.gov (United States)

    Rózyło-Kalinowska, Ingrid

    2007-05-01

    The distinction between radicular cysts and apical granulomas is a matter of considerable importance in making a treatment decision. Because there are no clearly defined radiographic criteria, the distinction is made on the grounds of size. However, it has been suggested that cysts can be distinguished from granulomas on the basis of their radiometric density. The results of previous studies have proved conflicting. To determine possibilities of application of digital radiography density measurements in differentiation of periapical granulomas and radicular cysts of inflammatory origin. The material consisted of 355 digital periapical radiograms obtained using Digora, RVG and Dixi 2 digital radiography systems in patients aged 20 to 84, divided into two groups: 259 granulomas and 102 radicular cysts. By means of Digora 2.0 software there were measured maximum and minimum densities along a line, then there was calculated the difference between maximum and minimum density. The largest dimensions of the lesions were measured - perpendicular and parallel to the root canal axis. It was proved that to some extent it was possible to differentiate cystic granulomas and radicular cysts on the basis of the difference between maximum and minimum density in linear measurement - when the difference exceeded 85.6 the lesion was a cyst and when it was below 45.9 a granuloma was diagnosed. Combination of two criteria - the calculated difference between densities and the largest dimension of a lesion, increased diagnostic possibilities of radiological differentiation of granulomas and radicular cysts.

  14. Dual-energy digital radiography for the assessment of bone mineral density

    Energy Technology Data Exchange (ETDEWEB)

    Tahvanainen, Paeivi S.; Lammentausta, Eveliina; Tervonen, Osmo; Jaemsae, Timo; Nieminen, Miika T. (Dept. of Diagnostic Radiology, Univ. of Oulu, Oulu (Finland)), e-mail: paivi.tahvanainen@oulu.fi; Pulkkinen, Pasi (Dept. of Medical Technology, Univ. of Oulu, Oulu (Finland))

    2010-06-15

    Background: Bone mineral density (BMD) is usually determined by dual-energy X-ray absorptiometry (DXA). Digital radiography (DR) has enabled the application of dual-energy techniques for separating bone and soft tissue, but it is not clear yet whether BMD information can reliably be obtained using DR. Purpose: To determine the ability of dual-energy digital radiography (DEDR) to predict BMD as determined by DXA. Material and Methods: Reindeer femora (n=15) were imaged in a water bath at a typical clinical imaging voltage of 79 kVp and additionally at 100 kVp on a DR system. BMD was determined in four segmented regions (femoral neck, trochanter, inter-trochanter, Ward's triangle) from these images using the DXA calculation principle. BMD results as determined by DEDR were compared with BMD values as determined by DXA. Results: Significant moderate to high linear correlations (0.66-0.76) were observed at the femoral neck, Ward's triangle, and trochanter between BMD values as determined by the two techniques. The coefficient of variation (CVRMS) ranged between 2.2 and 4.7% and 0.2 and 1.8% for DEDR and DXA analyses, respectively. Conclusion: DXA-based BMD information can be obtained with moderate precision and accuracy using DEDR. In future, combining BMD measurements using DEDR with structural and geometrical information available on digital radiographs could enable a more comprehensive assessment of bone . Keywords: BMD, DXA, bone assessment

  15. Prevalence of ligamentum arteriosum calcification on multi-section spiral CT and digital radiography.

    Science.gov (United States)

    Hong, Gil-Sun; Goo, Hyun Woo; Song, Jae-Woo

    2012-06-01

    To investigate the prevalence of ligamentum arteriosum calcification (LAC) on multi-section spiral CT and digital radiography. Five hundred and eight children and 232 adults who performed multi-section chest CT were included in this study and were divided into nine age groups: A (0-5 years), B (6-10 years), C (11-15 years), D (16-20 years), E (21-30 years), F (31-40 years), G (41-50 years), H (51-60 years), and I (61-70 years). Two radiologists assessed the presence of LAC on axial and coronal CT images, defined as focal calcific density on both or on one plane with attenuation >100 Hounsfield unit. The prevalence of LAC on CT was compared between children and adults, and between unenhanced and enhanced CT in children. The prevalence of LAC on digital radiography was evaluated in 476 children. The prevalence of definite LAC on unenhanced multi-section CT was significantly higher in children (37.8 %) than in adults (11.2 %) (P CT were 4.5, 12.8, 8.1, 19.0, 0.0, 0.0, 0.0, 2.0, and 1.9 %. In children, the prevalence of LAC was significantly higher on unenhanced than on enhanced CT (37.8 vs. 16.4 %, P children. LAC is frequently observed in children and adults on multi-section spiral CT, more frequently than previously reported. Compared with that on multi-section spiral CT, the prevalence of LAC on digital radiography is substantially low.

  16. Optimization of CMOS active pixels for high resolution digital radiography

    International Nuclear Information System (INIS)

    Kim, Young Soo

    2007-02-01

    CMOS image sensors have poorer performance compared to conventional charge coupled devices (CCDs). Since CMOS Active Pixel Sensors (APSs) in general have higher temporal noise, higher dark current, smaller full well charge capacitance, and lower spectral response, they cannot provide the same wide dynamic range and superior signal-to-noise ratio as CCDs. In view of electronic noise, the main source for the CMOS APS is the pixel, along with other signal processing blocks such as row and column decoder, analog signal processor (ASP), analog-to-digital converter (ADC), and timing and control logic circuitry. Therefore, it is important and necessary to characterize noise of the active pixels in CMOS APSs. We developed our theoretical noise model to account for the temporal noise in active pixels, and then found out the optimum design parameters such as fill actor, each size of the three transistors (source follower, row selection transistor, bias transistor) comprising active pixels, bias current, and load capacitance that can have the maximum signal-to-noise ratio. To develop the theoretical noise model in active pixels, we considered the integration noise of the photodiode and the readout noise of the transistors related to readout. During integration, the shot noise due to the dark current and photocurrent, during readout, the thermal and flicker noise were considered. The developed model can take the input variables such as photocurrent, capacitance of the photodiode, integration time, transconductance of the transistors, channel resistance of the transistors, gate-to-source capacitance of the follower, and load capacitance etc. To validate our noise model, two types of test structures have been realized. Firstly, four types of photodiodes (n_d_i_f_f_u_s_i_o_n/p_s_u_b_s_t_r_a_t_e, n_w_e_l_l/p_s_u_b_s_t_r_a_t_e, n_d_i_f_f_u_s_i_o_n/p_e_p_i_t_a_x_i_a_l/p_s_u_b_s_t_r_a_t_e, n_w_e_l_l/p_e_p_i_t_a_x_i_a_l/p_s_u_b_s_t_r_a_t_e) used in CMOS active pixels were fabricated

  17. Anatomic and energy variation of scatter compensation for digital chest radiography with Fourier deconvolution

    International Nuclear Information System (INIS)

    Floyd, C.E.; Beatty, P.T.; Ravin, C.E.

    1988-01-01

    The Fourier deconvolution algorithm for scatter compensation in digital chest radiography has been evaluated in four anatomically different regions at three energies. A shift invariant scatter distribution shape, optimized for the lung region at 140 kVp, was applied at 90 kVp and 120 kVp in the lung, retrocardiac, subdiaphragmatic, and thoracic spine regions. Scatter estimates from the deconvolution were compared with measured values. While some regional variation is apparent, the use of a shift invariant scatter distribution shape (optimized for a given energy) produces reasonable scatter compensation in the chest. A different set of deconvolution parameters were required at the different energies

  18. Demonstration of metallic implants by means of digital luminescence radiography (DLR)

    International Nuclear Information System (INIS)

    Wiesmann, W.; Reiser, M.; Fiebich, M.; Bick, U.; Peters, P.E.

    1990-01-01

    DLR makes it possible to integrate conventional radiography into digital communication and storage methods (PACS) into radiology. The use of DLR has been compared with conventional film methods in the demonstration of hip prostheses. The high contrast differences at the edge of the metal implant leads to artifacts, which could result in erroneous interpretation. Suitable image manipulation makes it possible, however, to eliminate these artifacts almost completely. DLR leads to an improvement in diagnosis in those complications not specifically related to the prostheses. (orig.) [de

  19. Construction of a physical phantom for quality control of digital radiography images

    International Nuclear Information System (INIS)

    Santos, Tayline T.; Azevedo, Priscila F.B. de; Vieira, Jose Wilson; Oliveira, Alex C.H. de; Lima, Fernando R. Andrade

    2014-01-01

    The advancement of technology in recent years has the production of increasingly sophisticated devices, in order thus to obtain medical images with high technical level and also facilitate the operation of the equipment. The phantoms were created to ensure a more accurate diagnosis with the minimum dose without exposing patients. Also, to obtain data and verify the performance of a radiography system with a view to ensuring the quality control standards. The objective of this paper is to present and validate a methodology for the construction of a phantom for the control of digital quality radiographic image. (author)

  20. Construction of a physical phantom for quality control of digital radiography images

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Tayline T.; Azevedo, Priscila F.B. de; Vieira, Jose Wilson, E-mail: taylinetyene@hotmail.com, E-mail: priscilafbrasil@yahoo.com.br [Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco (IFPE), Recife, PE (Brazil); Oliveira, Alex C.H. de; Lima, Fernando R. Andrade, E-mail: falima@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2014-07-01

    The advancement of technology in recent years has the production of increasingly sophisticated devices, in order thus to obtain medical images with high technical level and also facilitate the operation of the equipment. The phantoms were created to ensure a more accurate diagnosis with the minimum dose without exposing patients. Also, to obtain data and verify the performance of a radiography system with a view to ensuring the quality control standards. The objective of this paper is to present and validate a methodology for the construction of a phantom for the control of digital quality radiographic image. (author)

  1. Evaluation of the maxillary premolar roots dissociation using radiographic holders with conventional and digital radiography

    Directory of Open Access Journals (Sweden)

    Marcia Regina Ramalho da Silva Bardauil

    2010-09-01

    Full Text Available This in vivo study evaluated the dissociation quality of maxillary premolar roots combining variations of vertical and horizontal angulations by using X-ray holders (Rinn -XCP, and made a comparison between two types of intraoral radiography systems - conventional film (Kodak Insight, Rochester, USA and digital radiography (Kodak RVG 6100, Kodak, Rochester, USA. The study sample was comprised of 20 patients with a total of 20 maxillary premolars that were radiographed, using the paralleling angle technique (GP, with a 20º variation of the horizontal angle (GM and 25º variation of the horizontal angle combined with 15º vertical angle (GMV. Each image was independently analyzed by two experienced examiners. These examiners assigned a score to the diagnostic capability of root dissociation and the measurement of the distance between the apexes. Statistical data was derived using the Wilcoxon Signed Rank test, Friedman and T test. The means of the measured distances between buccal and lingual root apexes were greater for the GMV, which ranged from 2.3 mm to 3.3 mm. A statistically significant difference was found between GM and GMV when compared to GP with p < 0.01. An established best diagnostic dissociation roots image was found in the GMV. These results support the use of the anterior X-ray holders which offer a better combined deviation (GMV to dissociate maxillary premolar roots in both radiography systems.

  2. Film-screen vs. digital radiography in rheumatoid arthritis of the hand. An ROC analysis

    International Nuclear Information System (INIS)

    Jonsson, A.; Borg, A.; Hannesson, P.; Herrlin, K.; Jonsson, K.; Sloth, M.; Pettersson, H.

    1994-01-01

    In a prospective investigation the diagnostic accuracy of filmscreen and digital radiography in rheumatoid arthritis of hands was compared. Seventy hands of 36 patients with established rheumatoid arthritis were included in the study. Each of 11 joints in every hand was evaluated regarding the following radiologic parameters: soft tissue swelling, joint space narrowing, erosions and periarticular osteopenia. The digital images were obtained with storage phosphor image plates and evaluated in 2 forms; as digital hard-copy on film and on a monitor of an interactive workstation. The digital images had a resolution of either 3.33 or 5.0 lp/mm. ROC curves were constructed and comparing the area under the curves no significant difference was found between the 3 different imaging forms in either resolution group for soft tissue swelling, joint space narrowing and erosions. The film-screen image evaluation of periarticular osteopenia was significantly better than the digital hard-copy one in the 3.33 lp/mm resolution group, but no significant difference was found in the 5.0 lp/mm group. These results support the view that currently available digital systems are capable of adequate diagnostic performance. (orig.)

  3. [Digital luminescence radiography. A new method of study in thoracic diagnosis at the intensive care unit].

    Science.gov (United States)

    Witte, G; Pothmann, W; Bause, H; Nicolas, V; Schulte am Esch, J; Bücheler, E

    1989-02-01

    The digital luminescence-radiography (DLR) technique relies on a complete digitalization of the X-ray image. Luminescence crystals on the imaging plate serve as an energy reservoir following their exposure to ionized radiation from any conventional X-ray source. A Helium-Neon laser stimulates the electrons in their high energy bands and therefore will be dropped back emitting luminescence. This luminescence is digitized by the DLR-System thus delivering a complete digital image to the image processor for subsequent processing and evaluation. The processed digital image is then recorded on a conventional film or a monitor screen. More than 3000 chest examinations using DLR have been performed on intensive care unit (ICU) patients at the University Hospital Eppendorf following the first eleven months since the clinical introduction of this new technique. The positive aspects of DLR such as high-contrast resolution and optimal reproducibility were clinically evaluated under ICU conditions. It was shown that DLR greatly improves the quality of the chest X-rays of all ICU patients and offers the following advantages: reproducibility, lateral chest projection, no insufficient exposure, reduction of exposure dose, electronical post-processing and storage, quality preserving digital storage and copying.

  4. SU-F-P-06: Moving From Computed Radiography to Digital Radiography: A Collaborative Approach to Improve Image Quality

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval, D; Mlady, G; Selwyn, R [University of New Mexico School of Medicine, Albuquerque, NM (United States); Valenti, D; Bateman, T; Norris, V [University of New Mexico Hospital, Albuquerque, New Mexico (United States)

    2016-06-15

    Purpose: To bring together radiologists, technologists, and physicists to utilize post-processing techniques in digital radiography (DR) in order to optimize image acquisition and improve image quality. Methods: Sub-optimal images acquired on a new General Electric (GE) DR system were flagged for follow-up by radiologists and reviewed by technologists and medical physicists. Various exam types from adult musculoskeletal (n=35), adult chest (n=4), and pediatric (n=7) were chosen for review. 673 total images were reviewed. These images were processed using five customized algorithms provided by GE. An image score sheet was created allowing the radiologist to assign a numeric score to each of the processed images, this allowed for objective comparison to the original images. Each image was scored based on seven properties: 1) overall image look, 2) soft tissue contrast, 3) high contrast, 4) latitude, 5) tissue equalization, 6) edge enhancement, 7) visualization of structures. Additional space allowed for additional comments not captured in scoring categories. Radiologists scored the images from 1 – 10 with 1 being non-diagnostic quality and 10 being superior diagnostic quality. Scores for each custom algorithm for each image set were summed. The algorithm with the highest score for each image set was then set as the default processing. Results: Images placed into the PACS “QC folder” for image processing reasons decreased. Feedback from radiologists was, overall, that image quality for these studies had improved. All default processing for these image types was changed to the new algorithm. Conclusion: This work is an example of the collaboration between radiologists, technologists, and physicists at the University of New Mexico to add value to the radiology department. The significant amount of work required to prepare the processing algorithms, reprocessing and scoring of the images was eagerly taken on by all team members in order to produce better quality

  5. SU-F-P-06: Moving From Computed Radiography to Digital Radiography: A Collaborative Approach to Improve Image Quality

    International Nuclear Information System (INIS)

    Sandoval, D; Mlady, G; Selwyn, R; Valenti, D; Bateman, T; Norris, V

    2016-01-01

    Purpose: To bring together radiologists, technologists, and physicists to utilize post-processing techniques in digital radiography (DR) in order to optimize image acquisition and improve image quality. Methods: Sub-optimal images acquired on a new General Electric (GE) DR system were flagged for follow-up by radiologists and reviewed by technologists and medical physicists. Various exam types from adult musculoskeletal (n=35), adult chest (n=4), and pediatric (n=7) were chosen for review. 673 total images were reviewed. These images were processed using five customized algorithms provided by GE. An image score sheet was created allowing the radiologist to assign a numeric score to each of the processed images, this allowed for objective comparison to the original images. Each image was scored based on seven properties: 1) overall image look, 2) soft tissue contrast, 3) high contrast, 4) latitude, 5) tissue equalization, 6) edge enhancement, 7) visualization of structures. Additional space allowed for additional comments not captured in scoring categories. Radiologists scored the images from 1 – 10 with 1 being non-diagnostic quality and 10 being superior diagnostic quality. Scores for each custom algorithm for each image set were summed. The algorithm with the highest score for each image set was then set as the default processing. Results: Images placed into the PACS “QC folder” for image processing reasons decreased. Feedback from radiologists was, overall, that image quality for these studies had improved. All default processing for these image types was changed to the new algorithm. Conclusion: This work is an example of the collaboration between radiologists, technologists, and physicists at the University of New Mexico to add value to the radiology department. The significant amount of work required to prepare the processing algorithms, reprocessing and scoring of the images was eagerly taken on by all team members in order to produce better quality

  6. Electrical characteristics of hybrid detector based Gd2O2S:Tb-Selenium for digital radiation imaging

    International Nuclear Information System (INIS)

    Kang, Sang-Sik; Park, Ji-Koon; Choi, Jang-Yong; Cha, Byung-Yul; Cho, Sung-Ho; Nam, Sang-Hee

    2005-01-01

    Fine Gd 2 O 2 S:Tb powders were synthesized by using a solution-combustion method for a high-resolution digital X-ray imaging detector. The PL spectrum showed that the phosphor was fully crystallized and that the Tb 3+ ions substituted well for the Gd 3+ sites. To investigate the X-ray response of the phosphor, a uniform Gd 2 O 2 S:Tb film was grown using a screen-printing method. The X-ray sensitivities of the 100 μm-Gd 2 O 2 S:Tb/30 μm -Se and 200 μm -Se detector were 470 and 420 pC/cm 2 /mR, respectively, at an electric field of 10 V/μm. The results of the study suggest that the hybrid detector has a significant potential in the application of digital radiography and fluoroscopy systems

  7. Impact of matrix size on observer performance in digital chest radiography

    International Nuclear Information System (INIS)

    Koelblinger, C.

    2003-02-01

    This thesis compared the observer performance in the detection of abnormalities on 2k matrix(0,2 mm pixel size) and 4k matrix (0,1 mm pixel size) digital chest radiographs. Eighty five patients who underwent CT of the thorax were prospectively reccruited into the study. A chest x-ray of each patient was acquired in 2k and 4k format and four readers analyzed the images by different criterias. On the one hand a ROC analysis was performed with the CT data as goldstandard. On the other hand each reader had to rate different anatomical structures in a direct comparison of the pictures. The results of the ratings did not show any significant difference between the 2k and the 4k format. The conclusion or this study is that the use of a 4k instead of a 2k matrix in digital chest radiography does not yield to an improved observer performance. (author)

  8. Standard practice for digital imaging and communication nondestructive evaluation (DICONDE) for computed radiography (CR) test methods

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice facilitates the interoperability of computed radiography (CR) imaging and data acquisition equipment by specifying image data transfer and archival storage methods in commonly accepted terms. This practice is intended to be used in conjunction with Practice E2339 on Digital Imaging and Communication in Nondestructive Evaluation (DICONDE). Practice E2339 defines an industrial adaptation of the NEMA Standards Publication titled Digital Imaging and Communications in Medicine (DICOM, see http://medical.nema.org), an international standard for image data acquisition, review, storage and archival storage. The goal of Practice E2339, commonly referred to as DICONDE, is to provide a standard that facilitates the display and analysis of NDE results on any system conforming to the DICONDE standard. Toward that end, Practice E2339 provides a data dictionary and a set of information modules that are applicable to all NDE modalities. This practice supplements Practice E2339 by providing information objec...

  9. Optimization of digital chest radiography using computer modeling and voxels phantoms

    International Nuclear Information System (INIS)

    Correa, S.C.A.; Souza, E.M.; Silva, A.X.; Lopes, R.T.

    2009-01-01

    The purpose of this work is to use the Monte Carlo code MCNPX and the Female Adult voxel (FAX) and Male Adult voxel (MAX) phantoms to investigate how the dose and image quality in digital chest radiography vary with tube voltage (70-150 kV), anti-scatter methods (grid and air gap) and gender of the patient. The effective dose was calculated by ICRP60 and image quality was quantified by calculating the signal-difference-to-noise ratio for pathological details (calcifications) positioned at different locations in the anatomy. Calculated quantities were normalized to a fixed value of air kerma (5 μGy) at the automatic exposure control chambers. The results obtained in this work show that the air gap technique and lower tube voltages provide an increase in the digital image quality. Furthermore, this study has also shown that the detection of pathological details vary with the gender of the patient. (author)

  10. Radiography of scoliosis: comparative dosimetry between conventional technique and digital fluorography

    International Nuclear Information System (INIS)

    Gorincour, G.; Paris, M.; Aschero, A.; Bourliere, B.; Devred, P.; Petit, P.; Barrau, K.; Auquier, P.; Waultier, S.; Bourrelly, M.; Mundler, O.; Viehweger, E.; Jouve, J.L.; Bollini, G.

    2007-01-01

    Objective. Compare the irradiation delivered in conventional radiography and digital radiography by image intensifier during a scoliosis workup. Patients and Methods. Our prospective randomized study included 105 patients, all of whom were identified according to socio-demographic parameters as well as criteria evaluating the quality of the full front spinal x-ray at PA incidence. The entry dose at the scapula and the exit dose in inter-orbital, thyroid, mammary, and hypo-gastric projection was measured by thermoluminescent dosimeters. Results. The results of 71 girls and 28 boys, aged a mean 13.8 years with a mean weight of 47 kg were analyzed. At equal image quality, the entry dose was not significantly different between the two techniques; the mean exit dose reduction was 64% during digital acquisition. This reduction involved the inter-orbital (162%), mammary (43%), and thyroid (309%) regions. However, this system is more irradiating in the hypo-gastric region (34%). Conclusion. The dosimetric evaluation of the different imaging techniques used to explore the entirety of the spine should be part of radiologists' quality standard used to document their work and their choices. (authors)

  11. Accuracy of digital peripical radiography and cone-beam computed tomography in detecting external root resorption

    Energy Technology Data Exchange (ETDEWEB)

    Creanga, Adriana Gabriela [Division of Dental Diagnostic Science, Rutgers School of Dental Medicine, Newark (United States); Geha, Hassem; Sankar, Vidya; Mcmahan, Clyde Alex; Noujeim, Marcel [University of Texas Health Science Center San Antonio, San Antonio (United States); Teixeira, Fabrico B. [Dept. of Endodontics, University of Iowa, Iowa City (United States)

    2015-09-15

    The purpose of this study was to evaluate and compare the efficacy of cone-beam computed tomography (CBCT) and digital intraoral radiography in diagnosing simulated small external root resorption cavities. Cavities were drilled in 159 roots using a small spherical bur at different root levels and on all surfaces. The teeth were imaged both with intraoral digital radiography using image plates and with CBCT. Two sets of intraoral images were acquired per tooth: orthogonal (PA) which was the conventional periapical radiograph and mesioangulated (SET). Four readers were asked to rate their confidence level in detecting and locating the lesions. Receiver operating characteristic (ROC) analysis was performed to assess the accuracy of each modality in detecting the presence of lesions, the affected surface, and the affected level. Analysis of variation was used to compare the results and kappa analysis was used to evaluate interobserver agreement. A significant difference in the area under the ROC curves was found among the three modalities (P=0.0002), with CBCT (0.81) having a significantly higher value than PA (0.71) or SET (0.71). PA was slightly more accurate than SET, but the difference was not statistically significant. CBCT was also superior in locating the affected surface and level. CBCT has already proven its superiority in detecting multiple dental conditions, and this study shows it to likewise be superior in detecting and locating incipient external root resorption.

  12. Ongoing quality control in digital radiography: Report of AAPM Imaging Physics Committee Task Group 151

    International Nuclear Information System (INIS)

    Jones, A. Kyle; Geiser, William; Heintz, Philip; Goldman, Lee; Jerjian, Khachig; Martin, Melissa; Peck, Donald; Pfeiffer, Douglas; Ranger, Nicole; Yorkston, John

    2015-01-01

    Quality control (QC) in medical imaging is an ongoing process and not just a series of infrequent evaluations of medical imaging equipment. The QC process involves designing and implementing a QC program, collecting and analyzing data, investigating results that are outside the acceptance levels for the QC program, and taking corrective action to bring these results back to an acceptable level. The QC process involves key personnel in the imaging department, including the radiologist, radiologic technologist, and the qualified medical physicist (QMP). The QMP performs detailed equipment evaluations and helps with oversight of the QC program, the radiologic technologist is responsible for the day-to-day operation of the QC program. The continued need for ongoing QC in digital radiography has been highlighted in the scientific literature. The charge of this task group was to recommend consistency tests designed to be performed by a medical physicist or a radiologic technologist under the direction of a medical physicist to identify problems with an imaging system that need further evaluation by a medical physicist, including a fault tree to define actions that need to be taken when certain fault conditions are identified. The focus of this final report is the ongoing QC process, including rejected image analysis, exposure analysis, and artifact identification. These QC tasks are vital for the optimal operation of a department performing digital radiography

  13. A comparison of digital tomosynthesis and chest radiography in evaluating airway lesions using computed tomography as a reference

    International Nuclear Information System (INIS)

    Choo, Ji Yung; Lee, Ki Yeol; Choi, Jung Won; Yu, Ami; Kim, Je-Hyeong; Lee, Seung Heon; Kang, Eun-Young; Oh, Yu Whan

    2016-01-01

    To compare the diagnostic performance of digital tomosynthesis (DTS) and chest radiography for detecting airway abnormalities, using computed tomography (CT) as a reference. We evaluated 161 data sets from 149 patients (91 with and 70 without airway abnormalities) who had undergone radiography, DTS, and CT to detect airway problems. Radiographs and DTS were evaluated to localize and score the severity of the airway abnormalities, and to score the image quality using CT as a reference. Receiver operating characteristics (ROC), McNemar's test, weighted kappa, and the paired t-test were used for statistical analysis. The sensitivity of DTS was higher (reader 1, 93.51 %; reader 2, 94.29 %) than chest radiography (68.83 %; 71.43 %) in detecting airway lesions. The diagnostic accuracy of DTS (90.91 %; 94.70 %) was also significantly better than that of radiography (78.03 %; 82.58 %, all p < 0.05). DTS image quality was significantly better than chest radiography (1.83, 2.74; p < 0.05) in the results of both readers. The inter-observer agreement with respect to DTS findings was moderate and superior when compared to radiography findings. DTS is a more accurate and sensitive modality than radiography for detecting airway lesions that are easily obscured by soft tissue structures in the mediastinum. (orig.)

  14. Detection of rib fractures in an abused infant using digital radiography: a laboratory study

    Energy Technology Data Exchange (ETDEWEB)

    Kleinman, Paul K. [Department of Radiology, UMASS Memorial Health Care, 55 Lake Avenue North, Worcester, MA 01655 (United States); O' Connor, Brian; Nimkin, Katherine [Department of Pediatric Radiology, New England Medical Center, 750 Washington Street, Boston, MA 02111 (United States); Rayder, Shawn M. [Department of Radiology, Cape Cod Hospital, 12 Park Street, Hyannis, MA 02601-5203 (United States); Spevak, Melissa R. [Department of Radiology, Johns Hopkins Hospital, 600 N. Wolfe Street, Baltimore, MD 21287 (United States); Belanger, Patricia L. [University of Massachusetts, Amherst, MA 01003 (United States); Getty, David J. [BBNT Solutions LLC, 10 Moulton Street, Cambridge, MA 02138 (United States); Karellas, Andrew [Department of Radiology, University of Mass. Medical School, Lake Avenue North, Worcester, MA 01655 (United States)

    2002-12-01

    To assess the diagnostic performance of digital radiography using charge-coupled device (CCD) technology in the detection of rib fracture in infant abuse.Materials and methods. Four fractured posterior rib arcs and eight normal ribs removed at autopsy from a 10-month-old abused infant were radiographed using a CCD prototype, four clinical film-screen systems, and direct-exposure film. Each rib was viewed with these six systems in nine different projections. The resultant 648 images were assessed for probability of fracture (0-100%) by four pediatric radiologists. The calculated area under the resultant ROC curves (A{sub z}) for the CCD was compared with those obtained with direct-exposure, high-detail, medium and fast film-screen radiographic systems. The mean A{sub z} for the CCD (0.937) fell within the range of the high-detail systems (0.934-0.940) and was significantly higher (p<0.05) than the medium and fast system (0.861 and 0.858, respectively). Despite a lower spatial resolution than direct-exposure film (7 line pairs per millimeter vs. >20 line pairs per millimeter) the CCD performance was comparable (A{sub z}=0.944 vs. 0.937). The similar performance can be explained by the higher contrast resolution of the digital technology. This study indicates that in the ex vivo setting, digital radiology can perform comparably to high-detail film-screen imaging. The findings suggest that digital radiography has the potential to replace film-screen imaging in the evaluation of inflicted skeletal injury in infants. (orig.)

  15. Evaluation of Singh index for assessment of osteoporosis using digital radiography

    International Nuclear Information System (INIS)

    Hauschild, O.; Ghanem, N.; Oberst, M.; Baumann, T.; Kreuz, P.C.; Langer, M.; Suedkamp, N.P.; Niemeyer, P.

    2009-01-01

    Evaluation of Singh index (SI) as a simple means for estimating bone mass on radiographs has been subject of numerous studies. All of these studies used plain film radiographs for assessment of SI. Digital radiography may improve validity and reliability of SI assessment. Aim of this study was to evaluate SI gradings assessed on digital radiographs. Digital pelvic radiographs of 100 patients were graded using SI by five independent observers (two radiologists, three traumatologists) blinded to dual energy X-ray absorptiometry (DXA) results and re-graded by all observers for assessment of intraobserver agreement. SI was correlated with DXA measurements and after grouping the patients according to World Health Organisation (WHO) criteria (osteoporosis, osteopenia, normal). Logistic regression analysis was performed in order to identify influential parameters on the SI grading process. Mean intraobserver agreement was 0.648 ± 0.18 (Kendall's Tau) and 0.43 ± 0.28 (kappa). Mean interobserver agreement was 0.488 ± 0.193 (Kendall's Tau) and 0.199 ± 0.248 (kappa). Mean correlation between SI and trochanteric BMD and T scores was 0.219 ± 0.04 and 0.210 ± 0.05 (Spearman's coefficient). Only one observer (senior radiologist) reached the significance level after grouping the patients' DXA results according to WHO criteria and correlating the results with SI gradings. Logistic regression analysis revealed a significant influence of trochanteric T score in two observers while other variable parameters failed to reach the significance level. Even though we found reasonable intraobserver agreement assessment of SI is highly subjective and interobserver agreement is generally poor. Moreover, using digital radiography could not improve correlation with DXA measurements.

  16. Theoretical and experimental comparison of proton and helium-beam radiography using silicon pixel detectors

    Science.gov (United States)

    Gehrke, T.; Amato, C.; Berke, S.; Martišíková, M.

    2018-02-01

    Ion-beam radiography (iRAD) could potentially improve the quality control of ion-beam therapy. The main advantage of iRAD is the possibility to directly measure the integrated stopping power. Until now there is no clinical implementation of iRAD. Topics of ongoing research include developing dedicated detection systems to achieve the desired spatial resolution (SR) and investigating different ion types as imaging radiation. This work focuses on the theoretical and experimental comparison of proton (pRAD) and helium-beam radiography (αRAD). The experimental comparison was performed with an in-house developed detection system consisting of silicon pixel detectors. This system enables the measurement of energy deposition of single ions, their tracking, and the identification of the ion type, which is important for αRAD due to secondary fragments. A 161 mm-thick PMMA phantom with an air gap of 1 mm placed at different depths was imaged with a 168 MeV u-1 proton/helium-ion beam at the Heidelberg ion-beam therapy center. The image quality in terms of SR and contrast-to-noise ratio (CNR) was evaluated. After validating MC simulations against experiments, pRAD and αRAD were compared to carbon-beam radiography (cRAD) in simulations. The theoretical prediction that the CNR of pRAD and αRAD is equal at similar imaging doses was experimentally confirmed. The measured SR of αRAD was 55% better compared to pRAD. The simulated cRads showed the expected improvement in SR and the decreased CNR at the same dose compared to the αRads, however only at dose levels exceeding typical doses of diagnostic x-ray projections. For clinically applicable dose levels, the cRads suffered from an insufficient number of carbon ions per pixel (220 μm  ×  220 μm). In conclusion, it was theoretically and experimentally shown that αRAD provides a better SR than pRAD without any disadvantages concerning the CNR. Using carbon ions instead of helium ions leads to a better SR at the

  17. Criticality monitoring with digital systems and solid state neutron detectors

    International Nuclear Information System (INIS)

    Willhoite, S.B.

    1984-01-01

    A commercially available system for criticality monitoring combines the well established technology of digital radiation monitoring with state-of-the art detector systems capable of detecting criticality excursions of varying length and intensity with a high degree of confidence. The field microcomputer servicing the detector clusters contains hardware and software to acquire detector information in both the digital count rate and bit sensing modes supported by the criticality detectors. In both cases special criticality logic in the field microcomputer is used to determine the validity of the criticality event. The solid-state neutron detector consists of a 6 LiF wafer coupled to a diffused-junction charged particle detector. Alpha particles resulting from (n,α) interactions within the lithium wafer produce a pulsed signal corresponding to neutron intensity. Special detector circuitry causes the setting of a criticality bit recognizable by the microcomputer should neutron field intensities either exceed a hardware selectable frequency or saturate the detector resulting in a high current condition. These two modes of criticality sensing, in combination with the standard method of comparing an operator selectable alarm setpoint with the detector count rate, results in a criticality system capable of effective operation under the most demanding criticality monitoring conditions

  18. Screening for lung cancer with digital chest radiography: sensitivity and number of secondary work-up CT examinations

    NARCIS (Netherlands)

    de Hoop, Bartjan; Schaefer-Prokop, Cornelia; Gietema, Hester A.; de Jong, Pim A.; van Ginneken, Bram; van Klaveren, Rob J.; Prokop, Mathias

    2010-01-01

    To estimate the performance of digital chest radiography for detection of lung cancer. The study had ethics committee approval, and a nested case-control design was used and included 55 patients with lung cancer detected at computed tomography (CT) and confirmed with histologic examination and a

  19. Digital radiography - usability of experience in medical technology with fluorescent storage material for technical X-ray testing

    International Nuclear Information System (INIS)

    Mattis, A.; Winterberg, K.H.

    1992-01-01

    In nearly 100 years' development of X-ray technique, synergy effects between medical technology and non-destructive material testing (NDT) have repeatedly led to new applications. Thus digital radiography in medicine is a 'low dose' process introduced years ago which, by using a specially developed storage foil technique, offers extensive possibilities of application for NDT. (orig.) [de

  20. Spatial resolution requirements in digital radiography of scaphoid fractures. An ROC analysis

    International Nuclear Information System (INIS)

    Jonsson, A.; Laurin, S.; Karner, G.; Herrlin, K.; Hochbergs, P.; Jonsson, K.; Rudling, O.; Sandstroem, S.; Sloth, M.; Svahn, G.; Pettersson, H.

    1996-01-01

    Purpose: To investigate the spatial resolution requirements in digital radiography of scaphoid fractures. Material and Methods: Included in the study were 60 scaphoid radiographs with and 60 without fractures of the scaphoid bone. The film-screen images were digitized using pixel sizes of 115, 170, and 340 μm along with 170 μm with a 10:1 wavelet compression. The digital images were displayed on a 1280 x 1024 x 8 bits monitor, and 5 observers evaluated the images in 5 randomized sessions. The results for each pixel size were then compared to the film-screen images by ROC analysis. Results: The mean area under the ROC curves was larger for the film-screen images than for the digital images at all resolutions. However, this difference was not significant when the areas under the ROC curves for the film-screen images were compared to the digital images of 115, 170, and 170 μm with 10:1 compression. There was a significant difference for the 340-μm pixel size in favour of the film-screen images. The mean ROC curves for the digital images were very similar for the 115 and 170 μm pixel sizes, although slightly better for 115 μm. At 170 μm, the compression seemed to have a relatively small negative effect on the diagnostic performance; the deterioration was greater when the pixel size was increased to 340 μm. There was no obvious correlation between diagnostic performance and the experience of the observers in using workstations. Conclusions: The pixel size of 170 μm is adequate for the detection of subtle fractures, even after wavelet compression by a ratio of 10:1. (orig.)

  1. Status of the digital pixel array detector for protein crystallography

    CERN Document Server

    Datte, P; Beuville, E; Endres, N; Druillole, F; Luo, L; Millaud, J E; Xuong, N H

    1999-01-01

    A two-dimensional photon counting digital pixel array detector is being designed for static and time resolved protein crystallography. The room temperature detector will significantly enhance monochromatic and polychromatic protein crystallographic through-put data rates by more than three orders of magnitude. The detector has an almost infinite photon counting dynamic range and exhibits superior spatial resolution when compared to present crystallographic phosphor imaging plates or phosphor coupled CCD detectors. The detector is a high resistivity N-type Si with a pixel pitch of 150x150 mu m, and a thickness of 300 mu m, and is bump bonded to an application specific integrated circuit. The event driven readout of the detector is based on the column architecture and allows an independent pixel hit rate above 1 million photons/s/pixel. The device provides energy discrimination and sparse data readout which yields minimal dead-time. This type of architecture allows a continuous (frameless) data acquisition, a f...

  2. Diagnostic impact of digital tomosynthesis in oncologic patients with suspected pulmonary lesions on chest radiography.

    Science.gov (United States)

    Quaia, Emilio; Baratella, Elisa; Poillucci, Gabriele; Gennari, Antonio Giulio; Cova, Maria Assunta

    2016-08-01

    To assess the actual diagnostic impact of digital tomosynthesis (DTS) in oncologic patients with suspected pulmonary lesions on chest radiography (CXR). A total of 237 patients (135 male, 102 female; age, 70.8 ± 10.4 years) with a known primary malignancy and suspected pulmonary lesion(s) on CXR and who underwent DTS were retrospectively identified. Two radiologists (experience, 10 and 15 years) analysed in consensus CXR and DTS images and proposed a diagnosis according to a confidence score: 1 or 2 = definitely or probably benign pulmonary or extrapulmonary lesion, or pseudolesion; 3 = indeterminate; 4 or 5 = probably or definitely pulmonary lesion. DTS findings were proven by CT (n = 114 patients), CXR during follow-up (n = 105) or histology (n = 18). Final diagnoses included 77 pulmonary opacities, 26 pulmonary scars, 12 pleural lesions and 122 pulmonary pseudolesions. DTS vs CXR presented a higher (P chest radiography (CXR) in oncologic patients. • DTS improves confidence of CXR in oncologic patients. • DTS allowed avoidance of CT in about 50 % of oncologic patients.

  3. Infection control in digital intraoral radiography: evaluation of microbiological contamination of photostimulable phosphor plates in barrier envelopes.

    Science.gov (United States)

    MacDonald, David S; Waterfield, J Douglas

    2011-01-01

    The detectors (both solid-state sensors and photostimulable phosphor [PSP] plates) used for digital intraoral radiography cannot be autoclaved, and barriers are typically used to prevent the spread of infection. The aim of this study was to determine the effectiveness of a barrier envelope system for PSP plates. Disinfected PSP plates were aseptically inserted into barrier envelopes and placed in a periapical location. One PSP plate was placed in each of 28 patients, and 12 plates in each of 2 volunteers (D.S.M., J.D.W.). After retrieval, each PSP plate was removed from its barrier envelope, immersed in trypticase soy broth and aliquots were plated on trypticase soy agar. Bacterial colonies were counted 2 days later. Fifty-two PSP plates in barrier envelopes were evaluated for contamination. Quality assurance of the PSP plates before clinical placement revealed defects in the integrity of 4 barrier envelopes, caused by forceps-related damage or failure to achieve a uniform seal. These defects allowed substantial contamination. Contamination also occurred as a result of failure to extract the PSP plate from the barrier envelope cleanly. Of the 44 barriers with no obvious defects that were placed by either final-year dental students or a radiologist, only 3 allowed bacterial contamination of the PSP plate. Detectors contained in barrier envelopes remain a potential source of contamination. PSP plates must be disinfected between removal from a contaminated barrier envelope and placement in a new barrier envelope. In addition, placement into the barrier envelope should ideally be carried out under aseptic conditions. Finally, the integrity of each sealed barrier envelope must be verified visually before release to the clinic.

  4. Application of GaAs and CdTe photoconductor detectors to x-ray flash radiography

    International Nuclear Information System (INIS)

    Mathy, F.; Cuzin, M.; Gagelin, J.J.; Mermet, R.; Piaget, B.; Rustique, J.; Verger, L.

    1991-01-01

    Semi-insulating GaAs and CdTe:Cl photoconductor probes were qualified on high energy X ray single shot flash generators. The estimated minimum detected dose per flash corresponding to a 230 mrad direct beam attenuated by 200 mm lead was 20 μrad. The dynamic range was about 4 decades in amplitude or charges, with a good linearity. Such detectors, by locating the origin of the parasitic scattered beam, could be used to eliminate this parasitic beam in X ray flash radiography in detonics experiments. Imaging possibilities are mentioned, as well as X ray generator monitoring with such detectors or with neutron preirradiated photoconductors

  5. Application of GaAs and CdTe photoconductor detectors to X-ray flash radiography

    International Nuclear Information System (INIS)

    Mathy, F.; Cuzin, M.; Gagelin, J.J.; Mermet, R.; Piaget, B.; Rustique, J.; Verger, L.; Hauducoeur, A.; Nicolas, P.; Le Dain, L.; Hyvernage, M.

    1992-01-01

    Some insulating GaAs and CdTe:Cl photoconductor probes were qualified on high energy X-ray single-shot flash generators. The estimated minimum detected dose per flash corresponding to a 230 mrad direct beam attenuated by 200 mm lead was 20 μrad. The dynamic range was about 4 decades in amplitude or charge, with a good linearity. Such detectors, by locating the origin of the parasitic scattered beam, could be used to eliminate this parasitic beam in X-ray flash radiography in detonics experiments. Imaging possibilities are mentioned, as well as X-ray generator monitoring with such detectors or with neutron preirradiated photoconductors. (orig.)

  6. Application of GaAs and CdTe photoconductor detectors to X-ray flash radiography

    Energy Technology Data Exchange (ETDEWEB)

    Mathy, F.; Cuzin, M.; Gagelin, J.J.; Mermet, R.; Piaget, B.; Rustique, J.; Verger, L. (CEA, Direction des Technologies Avancees, Lab. d' Electronique, de Technologie et d' Instrumentation, DSYS, 38 - Grenoble (France)); Hauducoeur, A.; Nicolas, P.; Le Dain, L.; Hyvernage, M. (CEA, Direction des Applications Militaires, 77 - Courtry (France))

    1992-11-15

    Some insulating GaAs and CdTe:Cl photoconductor probes were qualified on high energy X-ray single-shot flash generators. The estimated minimum detected dose per flash corresponding to a 230 mrad direct beam attenuated by 200 mm lead was 20 [mu]rad. The dynamic range was about 4 decades in amplitude or charge, with a good linearity. Such detectors, by locating the origin of the parasitic scattered beam, could be used to eliminate this parasitic beam in X-ray flash radiography in detonics experiments. Imaging possibilities are mentioned, as well as X-ray generator monitoring with such detectors or with neutron preirradiated photoconductors. (orig.).

  7. Application of GaAs and CdTe photoconductor detectors to x-ray flash radiography

    Energy Technology Data Exchange (ETDEWEB)

    Mathy, F.; Cuzin, M.; Gagelin, J.J.; Mermet, R.; Piaget, B.; Rustique, J.; Verger, L. [CEA Centre d`Etudes de Grenoble, 38 (FR). Direction des Technologies Avancees; Hauducoeur, A.; Nicolas, P.; Le Dain, L.; Hyvernage, M. [CEA Centre d`Etudes de Vaujours, 77 - Courtry (FR)

    1991-12-31

    Semi-insulating GaAs and CdTe:Cl photoconductor probes were qualified on high energy X ray single shot flash generators. The estimated minimum detected dose per flash corresponding to a 230 mrad direct beam attenuated by 200 mm lead was 20 {mu}rad. The dynamic range was about 4 decades in amplitude or charges, with a good linearity. Such detectors, by locating the origin of the parasitic scattered beam, could be used to eliminate this parasitic beam in X ray flash radiography in detonics experiments. Imaging possibilities are mentioned, as well as X ray generator monitoring with such detectors or with neutron preirradiated photoconductors.

  8. Extra-oral dental radiography for disaster victims using a flat panel X-ray detector and a hand-held X-ray generator.

    Science.gov (United States)

    Ohtani, M; Oshima, T; Mimasaka, S

    2017-12-01

    Forensic odontologists commonly incise the skin for post-mortem dental examinations when it is difficult to open the victim's mouth. However, it is prohibited by law to incise dead bodies without permission in Japan. Therefore, we attempted using extra-oral dental radiography, using a digital X-ray equipment with rechargeable batteries, to overcome this restriction. A phantom was placed in the prone position on a table, and three plain dental radiographs were used per case: "lateral oblique radiographs" for left and right posterior teeth and a "contact radiograph" for anterior teeth were taken using a flat panel X-ray detector and a hand-held X-ray generator. The resolving power of the images was measured by a resolution test chart, and the scattered X-ray dose was measured using an ionization chamber-type survey meter. The resolving power of the flat panel X-ray detector was 3.0 lp/mm, which was less than that of intra-oral dental methods, but the three extra-oral plain dental radiographs provided the overall dental information from outside of the mouth, and this approach was less time-consuming. In addition, the higher dose of scattered X-rays was laterally distributed, but the dose per case was much less than that of intra-oral dental radiographs. Extra-oral plain dental radiography can be used for disaster victim identification by dental methods even when it is difficult to open the mouth. Portable and rechargeable devices, such as a flat panel X-ray detector and a hand-held X-ray generator, are convenient to bring and use anywhere, even at a disaster scene lacking electricity and water.

  9. Guidelines for anti-scatter grid use in pediatric digital radiography.

    Science.gov (United States)

    Fritz, Shannon; Jones, A Kyle

    2014-03-01

    Pediatric radiography presents unique challenges in balancing image quality and patient dose. Removing the anti-scatter grid reduces patient dose but also reduces image contrast. The benefit of using an anti-scatter grid decreases with decreasing patient size. To determine patient thickness thresholds for anti-scatter grid use by comparing scatter-to-primary ratio for progressively thinner patients without a grid to the scatter-to-primary ratio for a standard adult patient with a grid. We used Solid Water™ phantoms ranging in thickness from 7 cm to 16 cm to simulate pediatric abdomens. The scatter-to-primary ratio without a grid was measured for each thickness at 60 kVp, 70 kVp and 80 kVp for X-ray fields of view (FOV) of 378 cm(2), 690 cm(2) and 1,175 cm(2) using indirect digital radiography (iDR) and computed radiography (CR). We determined thresholds for anti-scatter grid use by comparing the intersection of a fit of scatter-to-primary ratio versus patient thickness with a standard adult scatter-to-primary ratio measured for a 23-cm phantom thickness at 80 kVp with an anti-scatter grid. Dose area product (DAP) was also calculated. The scatter-to-primary ratio depended strongly on FOV and weakly on kVp; however DAP increased with decreasing kVp. Threshold thicknesses for grid use varied from 5 cm for a 14 × 17-cm FOV using iDR to 12 cm for an 8 × 10-cm FOV using computed radiography. Removing the anti-scatter grid for small patients reduces patient dose without a substantial increase in scatter-to-primary ratio when the FOV is restricted appropriately. Radiologic technologists should base anti-scatter grid use on patient thickness and FOV rather than age.

  10. Image Gently: Challenges for radiologic technologists when performing digital radiography in children

    International Nuclear Information System (INIS)

    Goske, Marilyn J.; Smith, Susan N.; Charkot, Ellen; Herrmann, Tracy; John, Susan D.; Mills, Thalia T.; Morrison, Gregory

    2011-01-01

    The development of digital radiography (DR) has provided numerous benefits for pediatric imaging, including the ability to post-process images and to make images immediately available for access by care providers. However, DR presents several significant challenges for the radiologic technologists who are responsible for operating the equipment and producing high-quality images in children. This paper discusses those challenges, including lack of standardization among vendors, particularly with regard to the exposure indicator; lack of pediatric-specific educational materials and pediatric techniques; the need for manual technique instead of the use of automatic exposure control in smaller children; and complications related to field size, collimation and shielding in small children. Specific actions and design modifications that might facilitate the effective management of these challenges will be also described. The implementation of measures to promote the production of optimal images while minimizing radiation exposure requires cooperation and communication among imaging professionals, manufacturers and regulatory agencies. (orig.)

  11. Methodology for the construction of a physical phantom for quality control of images in digital radiography

    International Nuclear Information System (INIS)

    Santos, Tayline T.; Vieira, Jose Wilson; Oliveira, Alex Cristovao H. de; Lima, Fernando R. de Andrade

    2013-01-01

    The advancement of technology in recent years has provided the production of increasingly sophisticated devices, aiming to acquire medical images with high technical level and also facilitate the operational readiness of the equipment. In order to ensure the most accurate diagnosis with minimum dose without exposing patients to obtain data and verify the performance of a radiographic system for quality control purposes we use the so-called phantoms. Phantoms are physical or computational models used to simulate the transport of ionizing radiation, their interactions in the tissues of the human body and evaluate the deposition of energy. Besides, they are made from materials with behavior similar to human tissues when exposed to ionizing radiation - the so-called tissue-equivalent materials. This paper describes the construction of a physical phantom that allows the execution of the main acceptance tests of the quality control protocols in digital radiography

  12. Small animals bone density and morphometry analysis with a dual energy X-rays absorptiometry bone densitometer using a 2D digital radiographic detector; Analyse de la densite osseuse et de la morphometrie de petits animaux avec un osteodensitometre bi-energie utilisant un capteur 2D de radiographie numerique

    Energy Technology Data Exchange (ETDEWEB)

    Boudousq, V. [Centre Hospitalier Universitaire de Nimes, 30 (France); Bordy, T.; Gonon, G.; Dinten, J.M. [CEA Grenoble (DTBS/STD), Lab. d' Electronique et de Technologie de l' Informatique, LETI, 38 (France)

    2004-07-01

    LEXXOS (DMS, Montpellier, France) is the first axial and total body cone beam bone densitometer using a 2D digital radiographic detector. In previous papers, technical principles and patients' Bone Mineral Density (BMD) measurement performances were presented. Bone densitometers are also used on small animals for drug development. In this presentation, we show how LEXXOS can be adapted for small animals' examinations and evaluate its performances. At first, in order to take advantage of the whole area of the 20 x 20 cm{sup 2} digital radiographic detector, it has been made profit of X-Rays magnification by adapting the geometrical configuration. Secondly, as small animals present low BMD, a specific dual energy calibration has been defined. This adapted system has then been evaluated on two sets of mice: six reference mice and six ovariectomized mice. Each month, these two populations have been examined and the averaged total body BMD has been measured. This evaluation shows that the right order of BMD magnitude is obtained and, as expected, BMD increases on two sets until a period around puberty and the ovariectomized set presents a significant decrease after. Moreover, the bone image obtained by dual energy processing on LEXXOS presents a radiographic image quality providing useful complementary information on bone morphometry and architecture. This study shows that LEXXOS cone beam bone densitometer provides simultaneously useful quantitative and qualitative information for analysis of bone evolution on small animals. In the future, same system architecture and processing methodology can be used with higher resolution detectors in order to refine information on bone architecture. (authors)

  13. Energy-dependent imaging in digital radiography: a review on acquisition, processing and display technique

    International Nuclear Information System (INIS)

    Coppini, G.; Maltinti, G.; Valli, G.; Baroni, M.; Buchignan, M.; Valli, G.

    1986-01-01

    The capabilities of energy-dependent imaging in digital radiography are analyzed paying particular attention to digital video systems. The main techniques developed in recent years for selective energy imaging are reviewed following a unified approach. Discussion about advantages and limits of energy methods is carried out by a comparative analysis of computer simulated data and experimental results as obtained by standard x-ray equipments coupled to a digital video unit. Geometric phantoms are used as test object, as also images of a chest phantom are produced. Since signal-to-noise ratio degradation is one of the major problems when dealing with selective imaging, a particular effort is made to investigate noise effects. In this perspective, an original colour encoding display of energy sequences is presented. By mapping the various energy measurements on different colour bands (typically those of an RGB TV-monitor), an increased image conspicuity is obtained without a significant noise degradation: this is ensured by the energy dependence of attenuation coefficients and by the integrating characteristics of the display device

  14. An exposure indicator for digital radiography: AAPM Task Group 116 (executive summary).

    Science.gov (United States)

    Shepard, S Jeff; Wang, Jihong; Flynn, Michael; Gingold, Eric; Goldman, Lee; Krugh, Kerry; Leong, David L; Mah, Eugene; Ogden, Kent; Peck, Donald; Samei, Ehsan; Wang, Jihong; Willis, Charles E

    2009-07-01

    Digital radiographic imaging systems, such as those using photostimulable storage phosphor, amorphous selenium, amorphous silicon, CCD, and MOSFET technology, can produce adequate image quality over a much broader range of exposure levels than that of screen/film imaging systems. In screen/film imaging, the final image brightness and contrast are indicative of over- and underexposure. In digital imaging, brightness and contrast are often determined entirely by digital postprocessing of the acquired image data. Overexposure and underexposures are not readily recognizable. As a result, patient dose has a tendency to gradually increase over time after a department converts from screen/film-based imaging to digital radiographic imaging. The purpose of this report is to recommend a standard indicator which reflects the radiation exposure that is incident on a detector after every exposure event and that reflects the noise levels present in the image data. The intent is to facilitate the production of consistent, high quality digital radiographic images at acceptable patient doses. This should be based not on image optical density or brightness but on feedback regarding the detector exposure provided and actively monitored by the imaging system. A standard beam calibration condition is recommended that is based on RQA5 but uses filtration materials that are commonly available and simple to use. Recommendations on clinical implementation of the indices to control image quality and patient dose are derived from historical tolerance limits and presented as guidelines.

  15. 3600 digital phase detector with 100-kHz bandwidth

    International Nuclear Information System (INIS)

    Reid, D.W.; Riggin, D.; Fazio, M.V.; Biddle, R.S.; Patton, R.D.; Jackson, H.A.

    1981-01-01

    The general availability of digital circuit components with propagation delay times of a few nanoseconds makes a digital phase detector with good bandwidth feasible. Such a circuit has a distinct advantage over its analog counterpart because of its linearity over wide range of phase shift. A phase detector that is being built at Los Alamos National Laboratory for the Fusion Materials Irradiation Test (FMIT) project is described. The specifications are 100-kHz bandwidth, linearity of +- 1 0 over +- 180 0 of phase shift, and 0.66 0 resolution. To date, the circuit has achieved the bandwidth and resolution. The linearity is approximately +- 3 0 over +- 180 0 phase shift

  16. Multi-energy method of digital radiography for imaging of biological objects

    Science.gov (United States)

    Ryzhikov, V. D.; Naydenov, S. V.; Opolonin, O. D.; Volkov, V. G.; Smith, C. F.

    2016-03-01

    This work has been dedicated to the search for a new possibility to use multi-energy digital radiography (MER) for medical applications. Our work has included both theoretical and experimental investigations of 2-energy (2E) and 3- energy (3D) radiography for imaging the structure of biological objects. Using special simulation methods and digital analysis based on the X-ray interaction energy dependence for each element of importance to medical applications in the X-ray range of energy up to 150 keV, we have implemented a quasi-linear approximation for the energy dependence of the X-ray linear mass absorption coefficient μm (E) that permits us to determine the intrinsic structure of the biological objects. Our measurements utilize multiple X-ray tube voltages (50, 100, and 150 kV) with Al and Cu filters of different thicknesses to achieve 3-energy X-ray examination of objects. By doing so, we are able to achieve significantly improved imaging quality of the structure of the subject biological objects. To reconstruct and visualize the final images, we use both two-dimensional (2D) and three-dimensional (3D) palettes of identification. The result is a 2E and/or 3E representation of the object with color coding of each pixel according to the data outputs. Following the experimental measurements and post-processing, we produce a 3D image of the biological object - in the case of our trials, fragments or parts of chicken and turkey.

  17. Dosimetry and optimization in digital radiography based on the detail contrast resolution

    Energy Technology Data Exchange (ETDEWEB)

    Gomes B, W. O. [Instituto Federal da Bahia, Rua Emidio dos Santos s/n, Barbalho 40301-015, Salvador de Bahia (Brazil); Gomes de C, A., E-mail: wilsonottobatista@gmail.com [Secretaria de Saude do Estado da Bahia, Salvador de Bahia (Brazil)

    2016-10-15

    In digital radiography, computed radiography systems (CR) and portable panels a-Si (DR) are adapted to equipment previously used for the system screen / film. Therefore it maintains the characteristics as grid, filtration, yield, etc. Otherwise, the systems dedicated with a-Si panels (DR), are designed to operate with these image receptors. The ability to detect in low contrast details is reduced for all systems with increasing ratio of scattered radiation / primary radiation. In this context there is a need to acquire experience and adjust exposure protocols to ensure the quality of the image with maintaining kerma values in the surface as low as possible. The contrast resolution is defined as the ability of the system to distinguish similar degrees of attenuation of the object and is a parameter used to maintain the quality index and comparison between different systems. The protocols were: chest (90 and 102 kV with the range of 2-20 m As) and abdomen (80 kV in the range of 10-80 m As). Kerma values were evaluated with a solid state sensors. Based on analysis of these curves C-D, which identified the technique would imply a lower kerma input surface while maintaining image quality from the point of view of contrast-detail resolution. The results show that the IQFinv varies little throughout the range of m As, while the value of kerma varies linearly with in m As. Also, the complete analysis of the curves indicate that there was an increase in the definition of detail with increasing m As. The conclusion is that, in the transition phase of the new receivers are needed to assess and adjust practiced protocols to ensure the quality index of the image taking into account aspects of radiation protection of the patient. And even with digital technology, good radiographic technique should be practiced. (Author)

  18. Neutron-induced alpha radiography

    International Nuclear Information System (INIS)

    Pereira, Marco Antonio Stanojev

    2008-01-01

    A new radiography technique to inspect thin samples was developed. Low energy alpha particles, generated by a boron based screen under thermal neutron irradiation, are used as penetrating radiation. The solid state nuclear track detector CR-39 has been used to register the image. The interaction of the α - particles with the CR-39 gives rise to damages which under an adequate chemical etching became tracks the basic units forming the image. A digital system was developed for data acquisition and data analysis as well as for image processing. The irradiation and etching conditions to obtain the best radiography are 1,3 hours and 25 minutes at 70 deg C respectively. For such conditions samples having 10 μm in thickness can be inspected with a spatial resolution of 32 μm. The use of the digital system has reduced the time spent for data acquisition and data analysis and has improved the radiography image visualization. Furthermore, by using the digital system, it was possible to study several new parameters regarding the tracks which are very important to understand and study the image formation theory in solid state nuclear track detectors, the one used in this thesis. Some radiography images are also shown which demonstrate the potential of the proposed radiography technique. When compared with the other radiography techniques already in use to inspect thin samples, the present one developed in the present paper allows a smaller time to obtain the image, it is not necessary to handle liquid radioactive substances, the detector is insensitive to β, γ, X-ray and visible light. (author)

  19. Evaluation of diagnostic accuracy of conventional and digital periapical radiography, panoramic radiography, and cone-beam computed tomography in the assessment of alveolar bone loss

    Science.gov (United States)

    Takeshita, Wilton Mitsunari; Vessoni Iwaki, Lilian Cristina; Da Silva, Mariliani Chicarelli; Tonin, Renata Hernandes

    2014-01-01

    Background: To evaluate the diagnostic accuracy of different radiographic methods in the assessment of proximal alveolar bone loss (ABL). Materials and Methods: ABL, the distance between cement-enamel junction and alveolar bone crest, was measured in 70 mandibular human teeth – directly on the mandibles (control), using conventional periapical radiography with film holders (Rinn XCP and Han-Shin), digital periapical radiography with complementary metal-oxide semiconductor sensor, conventional panoramic, and cone-beam computed tomography (CBCT). Three programs were used to measure ABL on the images: Image tool 3.0 (University of Texas Health Sciences Center, San Antonio, Texas, USA), Kodak Imaging 6.1 (Kodak Dental Imaging 6.1, Carestream Health®, Rochester, NY, USA), and i-CAT vision 1.6.20. Statistical analysis used ANOVA and Tukey's test at 5% significance level. Results: The tomographic images showed the highest means, whereas the lowest were found for periapical with Han-Shin. Controls differed from periapical with Han-Shin (P digital periapical (P = 0.0027). Conventional periapicals with film holders differed from each other (P = 0.0007). Digital periapical differed from conventional periapical with Han-Shin (P = 0.0004). Conclusions: Conventional periapical with Han-Shin film holder was the only method that differed from the controls. CBCT had the closest means to the controls. PMID:25191066

  20. A comparison of digital radiography systems in terms of effective detective quantum efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Bertolini, Marco; Nitrosi, Andrea; Rivetti, Stefano; Lanconelli, Nico; Pattacini, Pierpaolo; Ginocchi, Vladimiro; Iori, Mauro [Department of Advanced Technology, Medical Physics Unit, Azienda Ospedaliera ASMN, Istituto di Ricovero e Cura a Carattere Scientifico, Reggio Emilia 42123 (Italy); Fisica Medica, Ospedale di Sassuolo S.p.A., Modena 41049 (Italy); Alma Mater Studiorum, Physics Department, University of Bologna, Bologna 40127 (Italy); Department of Diagnostic Imaging, Radiology Unit, Azienda Ospedaliera ASMN, Istituto di Ricovero e Cura a Carattere Scientifico, Reggio Emilia 42123 (Italy); Department of Diagnostic Imaging, Radiology Unit, Azienda USL, Reggio Emilia 42122 (Italy); Department of Advanced Technology, Medical Physics Unit, Azienda Ospedaliera ASMN, Istituto di Ricovero e Cura a Carattere Scientifico, Reggio Emilia 42123 (Italy)

    2012-05-15

    Purpose: The purpose of this study is to compare digital radiography systems using the metric effective detective quantum efficiency (eDQE), which better reflects digital radiography imaging system performance under clinical operating conditions, in comparison with conventional metrics such as modulation transfer function (MTF), normalized noise power spectra (NNPS), and detective quantum efficiency (DQE). Methods: The eDQE was computed by the calculation of the MTF, the NNPS, the phantom attenuation and scatter, and estimation of x-ray flux. The physical characterization of the systems was obtained with the standard beam conditions RQA5 and RQA9, using the PA Chest phantom proposed by AAPM Report no. 31 simulating the attenuation and scatter characteristics of the adult human thorax. The MTF (eMTF) was measured by using an edge test placed at the frontal surface of the phantom, the NNPS (eNNPS) was calculated from images of the phantom acquired at three different exposure levels covering the operating range of the system (E{sub 0}, which is the exposure at which a system is normally operated, 1/3 E{sub 0}, and 3 E0), and scatter measurements were assessed by using a beam-stop technique. The integral of DQE (IDQE) and eDQE (IeDQE) was calculated over the whole spatial frequency range. Results: The eMTF results demonstrate degradation due to magnification and the presence of scattered radiation. The eNNPS was influenced by the grid presence, and in some systems, it contained structured noise. At typical clinical exposure levels, the magnitude of eDQE(0) with respect to DQE(0) at RQA9 beam conditions was 13%, 17%, 16%, 36%, and 24%, respectively, for Carestream DRX-1, Carestream DRX-1C, Carestream Direct View CR975, Philips Digital Diagnost VM, and GE Revolution XR/d. These results were confirmed by the ratio of IeDQE and IDQE in the same conditions. Conclusions: The authors confirm the robustness and reproducibility of the eDQE method. As expected, the DR systems

  1. A comparison of digital radiography systems in terms of effective detective quantum efficiency

    International Nuclear Information System (INIS)

    Bertolini, Marco; Nitrosi, Andrea; Rivetti, Stefano; Lanconelli, Nico; Pattacini, Pierpaolo; Ginocchi, Vladimiro; Iori, Mauro

    2012-01-01

    Purpose: The purpose of this study is to compare digital radiography systems using the metric effective detective quantum efficiency (eDQE), which better reflects digital radiography imaging system performance under clinical operating conditions, in comparison with conventional metrics such as modulation transfer function (MTF), normalized noise power spectra (NNPS), and detective quantum efficiency (DQE). Methods: The eDQE was computed by the calculation of the MTF, the NNPS, the phantom attenuation and scatter, and estimation of x-ray flux. The physical characterization of the systems was obtained with the standard beam conditions RQA5 and RQA9, using the PA Chest phantom proposed by AAPM Report no. 31 simulating the attenuation and scatter characteristics of the adult human thorax. The MTF (eMTF) was measured by using an edge test placed at the frontal surface of the phantom, the NNPS (eNNPS) was calculated from images of the phantom acquired at three different exposure levels covering the operating range of the system (E 0 , which is the exposure at which a system is normally operated, 1/3 E 0 , and 3 E0), and scatter measurements were assessed by using a beam-stop technique. The integral of DQE (IDQE) and eDQE (IeDQE) was calculated over the whole spatial frequency range. Results: The eMTF results demonstrate degradation due to magnification and the presence of scattered radiation. The eNNPS was influenced by the grid presence, and in some systems, it contained structured noise. At typical clinical exposure levels, the magnitude of eDQE(0) with respect to DQE(0) at RQA9 beam conditions was 13%, 17%, 16%, 36%, and 24%, respectively, for Carestream DRX-1, Carestream DRX-1C, Carestream Direct View CR975, Philips Digital Diagnost VM, and GE Revolution XR/d. These results were confirmed by the ratio of IeDQE and IDQE in the same conditions. Conclusions: The authors confirm the robustness and reproducibility of the eDQE method. As expected, the DR systems performed

  2. Digital image intensifier radiography: first experiences with the DSI (Digital Spot Imaging)

    International Nuclear Information System (INIS)

    Rueckforth, J.; Wein, B.; Stargardt, A.; Guenther, R.W.

    1995-01-01

    We performed a comparative study of digitally and conventionally acquired images in gastrointestinal examinations. Radiation dose and spatial resolution were determined in a water phantom. In 676 examinations with either conventional or digital imaging (system: Diagnost 76, DSI) the number of images and the duration of the fluoroscopy time were compared. 101 examinations with digital as well as conventional documentation were evaluated by using 5 criteria describing the diagnostic performance. The entrance dose of the DSI is 12% to 36% of the film/screen system and the spatial resolution of the DSI may be better than that of a film/screen system with a speed of 200. The fluoroscopy time shows no significant difference between DSI and the film/screen technique. In 2 of 4 examination modes significantly more images were produced by the DSI. With exception of the criterion of edge sharpness, DSI yields a significantly inferior assessment compared with the film/screen technique. (orig./MG) [de

  3. Heel effect adaptive flat field correction of digital x-ray detectors

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yongjian [X-ray Products, Varian Medical Systems Inc., Liverpool, New York 13088 (United States); Wang, Jue [Department of Mathematics, Union College, Schenectady, New York 12308 (United States)

    2013-08-15

    Purpose: Anode heel effect renders large-scale background nonuniformities in digital radiographs. Conventional offset/gain calibration is performed at mono source-to-image distance (SID), and disregards the SID-dependent characteristic of heel effect. It results in a residual nonuniform background in the corrected radiographs when the SID settings for calibration and correction differ. In this work, the authors develop a robust and efficient computational method for digital x-ray detector gain correction adapted to SID-variant heel effect, without resorting to physical filters, phantoms, complicated heel effect models, or multiple-SID calibration and interpolation.Methods: The authors present the Duo-SID projection correction method. In our approach, conventional offset/gain calibrations are performed only twice, at the minimum and maximum SIDs of the system in typical clinical use. A fast iterative separation algorithm is devised to extract the detector gain and basis heel patterns from the min/max SID calibrations. The resultant detector gain is independent of SID, while the basis heel patterns are parameterized by the min- and max-SID. The heel pattern at any SID is obtained from the min-SID basis heel pattern via projection imaging principles. The system gain desired at a specific acquisition SID is then constructed using the projected heel pattern and detector gain map.Results: The method was evaluated for flat field and anatomical phantom image corrections. It demonstrated promising improvements over interpolation and conventional gain calibration/correction methods, lowering their correction errors by approximately 70% and 80%, respectively. The separation algorithm was able to extract the detector gain and heel patterns with less than 2% error, and the Duo-SID corrected images showed perceptually appealing uniform background across the detector.Conclusions: The Duo-SID correction method has substantially improved on conventional offset/gain corrections for

  4. Heel effect adaptive flat field correction of digital x-ray detectors

    International Nuclear Information System (INIS)

    Yu, Yongjian; Wang, Jue

    2013-01-01

    Purpose: Anode heel effect renders large-scale background nonuniformities in digital radiographs. Conventional offset/gain calibration is performed at mono source-to-image distance (SID), and disregards the SID-dependent characteristic of heel effect. It results in a residual nonuniform background in the corrected radiographs when the SID settings for calibration and correction differ. In this work, the authors develop a robust and efficient computational method for digital x-ray detector gain correction adapted to SID-variant heel effect, without resorting to physical filters, phantoms, complicated heel effect models, or multiple-SID calibration and interpolation.Methods: The authors present the Duo-SID projection correction method. In our approach, conventional offset/gain calibrations are performed only twice, at the minimum and maximum SIDs of the system in typical clinical use. A fast iterative separation algorithm is devised to extract the detector gain and basis heel patterns from the min/max SID calibrations. The resultant detector gain is independent of SID, while the basis heel patterns are parameterized by the min- and max-SID. The heel pattern at any SID is obtained from the min-SID basis heel pattern via projection imaging principles. The system gain desired at a specific acquisition SID is then constructed using the projected heel pattern and detector gain map.Results: The method was evaluated for flat field and anatomical phantom image corrections. It demonstrated promising improvements over interpolation and conventional gain calibration/correction methods, lowering their correction errors by approximately 70% and 80%, respectively. The separation algorithm was able to extract the detector gain and heel patterns with less than 2% error, and the Duo-SID corrected images showed perceptually appealing uniform background across the detector.Conclusions: The Duo-SID correction method has substantially improved on conventional offset/gain corrections for

  5. Digital readouts for large microwave low-temperature detector arrays

    International Nuclear Information System (INIS)

    Mazin, Benjamin A.; Day, Peter K.; Irwin, Kent D.; Reintsema, Carl D.; Zmuidzinas, Jonas

    2006-01-01

    Over the last several years many different types of low-temperature detectors (LTDs) have been developed that use a microwave resonant circuit as part of their readout. These devices include microwave kinetic inductance detectors (MKID), microwave SQUID readouts for transition edge sensors (TES), and NIS bolometers. Current readout techniques for these devices use analog frequency synthesizers and IQ mixers. While these components are available as microwave integrated circuits, one set is required for each resonator. We are exploring a new readout technique for this class of detectors based on a commercial-off-the-shelf technology called software defined radio (SDR). In this method a fast digital to analog (D/A) converter creates as many tones as desired in the available bandwidth. Our prototype system employs a 100MS/s 16-bit D/A to generate an arbitrary number of tones in 50MHz of bandwidth. This signal is then mixed up to the desired detector resonant frequency (∼10GHz), sent through the detector, then mixed back down to baseband. The baseband signal is then digitized with a series of fast analog to digital converters (80MS/s, 14-bit). Next, a numerical mixer in a dedicated integrated circuit or FPGA mixes the resonant frequency of a specified detector to 0Hz, and sends the complex detector output over a computer bus for processing and storage. In this paper we will report on our results in using a prototype system to readout a MKID array, including system noise performance, X-ray pulse response, and cross-talk measurements. We will also discuss how this technique can be scaled to read out many thousands of detectors

  6. A Monte-Carlo simulation framework for joint optimisation of image quality and patient dose in digital paediatric radiography

    International Nuclear Information System (INIS)

    Menser, Bernd; Manke, Dirk; Mentrup, Detlef; Neitzel, Ulrich

    2016-01-01

    In paediatric radiography, according to the as low as reasonably achievable (ALARA) principle, the imaging task should be performed with the lowest possible radiation dose. This paper describes a Monte-Carlo simulation framework for dose optimisation of imaging parameters in digital paediatric radiography. Patient models with high spatial resolution and organ segmentation enable the simultaneous evaluation of image quality and patient dose on the same simulated radiographic examination. The accuracy of the image simulation is analysed by comparing simulated and acquired images of technical phantoms. As a first application example, the framework is applied to optimise tube voltage and pre-filtration in newborn chest radiography. At equal patient dose, the highest CNR is obtained with low-kV settings in combination with copper filtration. (authors)

  7. The digital flat-panel X-Ray detectors

    International Nuclear Information System (INIS)

    Risticj, S. Goran

    2013-01-01

    In a digital imaging system, the incident x-ray image must be sampled both in the spatial and intensity dimensions. In the spatial dimensions, samples are obtained as averages of the intensity over picture elements or pixels. In the intensity dimension, the signal is digitalized into one of a finite number of levels or bits. Two main types of digital flat-panel detectors are based on the direct conversion, which contains the photoconductor, and on indirect conversion, which contains phosphor. The basics of these detectors are given. Coupling traditional x-ray detection material such as photoconductors and phosphors with a large-area active-matrix readout structure forms the basis of flat panel x-ray images. Active matrix technology provides a new, highly efficient, real time method for electronically storing and measuring the product of the x-ray interaction stage whether the product is visible wavelength photons or electrical charges. The direct and indirect detectors, made as the active-matrix flat-panel detectors containing sensing/storage elements, switching elements (diodes or thin film transistors (TFTS)) and image processing module, are described. Strengths and limitations of stimulable phosphors are discussed. The main advantages and disadvantages of mentioned x-ray detectors are also analyzed. (Author)

  8. A Versatile Image Processor For Digital Diagnostic Imaging And Its Application In Computed Radiography

    Science.gov (United States)

    Blume, H.; Alexandru, R.; Applegate, R.; Giordano, T.; Kamiya, K.; Kresina, R.

    1986-06-01

    In a digital diagnostic imaging department, the majority of operations for handling and processing of images can be grouped into a small set of basic operations, such as image data buffering and storage, image processing and analysis, image display, image data transmission and image data compression. These operations occur in almost all nodes of the diagnostic imaging communications network of the department. An image processor architecture was developed in which each of these functions has been mapped into hardware and software modules. The modular approach has advantages in terms of economics, service, expandability and upgradeability. The architectural design is based on the principles of hierarchical functionality, distributed and parallel processing and aims at real time response. Parallel processing and real time response is facilitated in part by a dual bus system: a VME control bus and a high speed image data bus, consisting of 8 independent parallel 16-bit busses, capable of handling combined up to 144 MBytes/sec. The presented image processor is versatile enough to meet the video rate processing needs of digital subtraction angiography, the large pixel matrix processing requirements of static projection radiography, or the broad range of manipulation and display needs of a multi-modality diagnostic work station. Several hardware modules are described in detail. For illustrating the capabilities of the image processor, processed 2000 x 2000 pixel computed radiographs are shown and estimated computation times for executing the processing opera-tions are presented.

  9. Automatic method for selective enhancement of different tissue densities at digital chest radiography

    International Nuclear Information System (INIS)

    McNitt-Gray, M.F.; Taira, R.K.; Eldredge, S.L.; Razavi, M.

    1991-01-01

    This paper reports that digital chest radiographs often are too bright and/or lack contrast when viewed on a video display. The authors have developed a method that can automatically provide a series of look-up tables that selectively enhance the radiographically soft or dense tissues on a digital chest radiograph. This reduces viewer interaction and improves displayed image quality. On the basis of a histogram analysis, gray-level ranges are approximated for the patient background, radiographically soft tissues, and radiographically dense tissues. A series of look-up tables is automatically created by varying the contrast in each range to achieve a level of enhancement for a selected tissue range. This is repeated for differing amounts of enhancement and for each tissue range. This allows the viewer to interactively select a tissue density range and degree of enhancement at the time of display via precalculated look-up tables. Preclinical trials in pediatric radiology using computed radiography images show that this method reduces viewer interaction and improves or maintains the displayed image quality

  10. Benchmarking the performance of fixed-image receptor digital radiography systems. Part 2: system performance metric.

    Science.gov (United States)

    Lee, Kam L; Bernardo, Michael; Ireland, Timothy A

    2016-06-01

    This is part two of a two-part study in benchmarking system performance of fixed digital radiographic systems. The study compares the system performance of seven fixed digital radiography systems based on quantitative metrics like modulation transfer function (sMTF), normalised noise power spectrum (sNNPS), detective quantum efficiency (sDQE) and entrance surface air kerma (ESAK). It was found that the most efficient image receptors (greatest sDQE) were not necessarily operating at the lowest ESAK. In part one of this study, sMTF is shown to depend on system configuration while sNNPS is shown to be relatively consistent across systems. Systems are ranked on their signal-to-noise ratio efficiency (sDQE) and their ESAK. Systems using the same equipment configuration do not necessarily have the same system performance. This implies radiographic practice at the site will have an impact on the overall system performance. In general, systems are more dose efficient at low dose settings.

  11. Nodule detection in digital chest radiography: Introduction to the radius chest trial

    International Nuclear Information System (INIS)

    Baath, M.; Haakansson, M.; Boerjesson, S.; Kheddache, S.; Grahn, A.; Ruschin, M.; Tingberg, A.; Mattsson, S.; Maansson, L. G.

    2005-01-01

    Most digital radiographic systems of today have wide latitude and are hence able to provide images with a small constraint on dose level. This opens up for an unprejudiced dose optimisation. However, in order to succeed in the optimisation task, good knowledge of the imaging and detection processes is needed. As a part of the European-wide research project 'unification of physical and clinical requirements for medical X-ray imaging - governed by the Radiological Imaging Unification Strategies (RADIUS) Group - a major image quality trial was conducted by members of the group. The RADIUS chest trial was focused on the detection of lung nodules in digital chest radiography with the aims of determining to what extent (1) the detection of a nodule is dependent on its location, (2) the system noise disturbs the detection of lung nodules, (3) the anatomical noise disturbs the detection of lung nodules and (4) the image background and anatomical background act as pure noise for the detection of lung nodules. The purpose of the present paper is to give an introduction to the trial and describe the framework and set-up of the investigation. (authors)

  12. Digital radiography of scoliosis with a scanning method: radiation dose optimization

    Energy Technology Data Exchange (ETDEWEB)

    Geijer, Haakan; Andersson, Torbjoern [Department of Radiology, Oerebro University Hospital, 701 85 Oerebro (Sweden); Verdonck, Bert [Philips Medical Systems, P.O. Box 10,000, 5680 Best (Netherlands); Beckman, Karl-Wilhelm; Persliden, Jan [Department of Medical Physics, Oerebro University Hospital, 701 85 Oerebro (Sweden)

    2003-03-01

    The aim of this study was optimization of the radiation dose-image quality relationship for a digital scanning method of scoliosis radiography. The examination is performed as a digital multi-image translation scan that is reconstructed to a single image in a workstation. Entrance dose was recorded with thermoluminescent dosimeters placed dorsally on an Alderson phantom. At the same time, kerma area product (KAP) values were recorded. A Monte Carlo calculation of effective dose was also made. Image quality was evaluated with a contrast-detail phantom and Visual Grading. The radiation dose was reduced by lowering the image intensifier entrance dose request, adjusting pulse frequency and scan speed, and by raising tube voltage. The calculated effective dose was reduced from 0.15 to 0.05 mSv with reduction of KAP from 1.07 to 0.25 Gy cm{sup 2} and entrance dose from 0.90 to 0.21 mGy. The image quality was reduced with the Image Quality Figure going from 52 to 62 and a corresponding reduction in image quality as assessed with Visual Grading. The optimization resulted in a dose reduction to 31% of the original effective dose with an acceptable reduction in image quality considering the intended use of the images for angle measurements. (orig.)

  13. Comparison of digital tomosynthesis and chest radiography for the detection of pulmonary nodules: systematic review and meta-analysis.

    Science.gov (United States)

    Kim, Jun H; Lee, Kyung H; Kim, Kyoung-Tae; Kim, Hyun J; Ahn, Hyeong S; Kim, Yeo J; Lee, Ha Y; Jeon, Yong S

    2016-12-01

    To compare the diagnostic accuracy of digital tomosynthesis (DTS) with that of chest radiography for the detection of pulmonary nodules by meta-analysis. A systematic literature search was performed to identify relevant original studies from 1 January 1 1976 to 31 August 31 2016. The quality of included studies was assessed by quality assessment of diagnostic accuracy studies-2. Per-patient data were used to calculate the sensitivity and specificity and per-lesion data were used to calculate the detection rate. Summary receiver-operating characteristic curves were drawn for pulmonary nodule detection. 16 studies met the inclusion criteria. 1017 patients on a per-patient basis and 2159 lesions on a per-lesion basis from 16 eligible studies were evaluated. The pooled patient-based sensitivity of DTS was 0.85 [95% confidence interval (CI) 0.83-0.88] and the specificity was 0.95 (0.93-0.96). The pooled sensitivity and specificity of chest radiography were 0.47 (0.44-0.51) and 0.37 (0.34-0.40), respectively. The per-lesion detection rate was 2.90 (95% CI 2.63-3.19). DTS has higher diagnostic accuracy than chest radiography for detection of pulmonary nodules. Chest radiography has low sensitivity but similar specificity, comparable with that of DTS. Advances in knowledge: DTS has higher diagnostic accuracy than chest radiography for the detection of pulmonary nodules.

  14. Comparison of digital selenium radiography with an analog screen-film system in the diagnostic process of pneumoconiosis according to ILO classification

    International Nuclear Information System (INIS)

    Zaehringer, M.; Winnekendonk, G.; Gossmann, A.; Krueger, K.; Krug, B.

    2001-01-01

    Purpose: The aim of the study was to determine the diagnostic value of digital selenium radiography in patients with pneumoconiosis. For this purpose chest X-rays by digital selenium radiography and analog screen-film system were compared according to the ILO classification of pneumoconiosis. Method: After approval of the study by the local ethic commission and the Federal German Office for Radiation Protection 50 patients were subjected to X-rays by digital selenium radiography (Thoravision; Philips Medical Systems, Hamburg, Germany) and analog screen-film system of the same day within the scope of an industrial medicine preventive checkup. Four investigators rated the chest X-rays according to the ILO classification of pneumoconiosis. Results: The findings demonstrated by chest X-rays according to ILO classification were rated similar by digital selenium radiography and analog screen film systems. Image quality of the digital pictures was rated significantly better. Conclusion: The use of digital selenium radiography in evaluating chest X-rays according to the ILO classification does not result in over- or underestimation of pulmonary pathologies. Hence, in the diagnosis of pneumoconiosis, digital selenium radiography can replace the tested analog screen-film system. (orig.) [de

  15. Intraoperative digital specimen radiography in the treatment of nonpalpable breast lesions

    Directory of Open Access Journals (Sweden)

    Vicko Ferenc

    2017-01-01

    Full Text Available Introduction/Objective. About a third of the breast lesions on mammography are clinically occult. The goals of surgical treatment are to locate, remove, and verify their presence in the removed breast tissue. Standard specimen mammography (SSM has been an official procedure for the latter, while intraoperative digital specimen radiography (IDSR was introduced recently. The aim of this study was to evaluate the use of IDSR versus SSM and possible benefits regarding the duration of the procedures (operating room occupancy, availability of digital mammography for additional number of patients, surgeon productivity, and the quality of performed services. Methods. A retrospective chart review of 109 patients who underwent IDSR for nonpalpable breast lesions was performed between January 2014 and June 2016. We compared the difference in the duration of IDSR versus SSM procedure. We also observed the number of re-excisions and evaluated time-saving in the operating room workflow. Results. The average duration of surgery in the IDSR group of patients was 51 minutes, compared to 64 minutes in the SSM group. Every IDSR procedure saved 13 minutes over the standard SSM. That would allow another 28 procedures in the same time frame, with the same quality of service compared with SSM. In that way we increased productivity by 27.5%. Additional operation/surgery was needed for histologically involved surgical margins in three cases (2.75%. Conclusion. The use of new technology resulted in the rationalization of the operative room workflow and gave better productivity. More savings were obtained through the increase of digital mammography capacity for diagnostics, decrease of anesthesia duration, and better management of human resources. The number of “true” re-excisions, involving additional surgery, remained similar after introducing IDSR.

  16. New developments in radiography. An overview

    International Nuclear Information System (INIS)

    Berger, H.; Orphan, V.

    1983-01-01

    Techniques for radiographic inspection are undergoing change. Changes in X-ray sources include higher voltage and current, pulse techniques, smaller focal spots, portability, ease-of-use, and high reliability. Detector improvements include better films, screens and scintillators, real-time methods, electrostatic methods and solid state detectors. We now use many radiation for radiography (X-rays, gamma rays, neutrons and charged particles) and can process radiographic information to accomplish such things as image enhancement, tomography and digital radiography. In this review, the authors discuss some of these developments, many of which have not been applied - or widely applied in the nuclear industry

  17. Detection of artificial air space opacities with digital radiography. Ex vivo study on enhanced latitude post-processing

    International Nuclear Information System (INIS)

    Biederer, Juergen; Bolte, H.; Schmidt, T.; Charalambous, N.; Both, M.; Hoffmann, B.; Heller, M.; Kopp, U.; Freitag-Wolf, S.; Van Metter, R.

    2010-01-01

    Purpose: To evaluate in a.-p. digital chest radiograms of an ex vivo system if increased latitude and enhanced image detail contrast (EVP) improve the accuracy of detecting artificial air space opacities in parts of the lung that are superimposed by the diaphragm. Materials and Methods: 19 porcine lungs were inflated inside a chest phantom, prepared with 20-50 ml gelatin-stabilized liquid to generate alveolar air space opacities, and examined with direct radiography (3.0 x 2.5 k detector/125 kVp/4 mAs). 276 a.-p. images with and without EVP of 1.0-3.0 were presented to 6 observers. 8 regions were read for opacities, the reference was defined by CT. Statistics included sensitivity/specificity, interobserver variability, and calculation of Az (area under ROC curve). Results: Behind the diaphragm (opacities in 32/92 regions), the median sensitivity increased from 0.35 without EVP to 0.53 - 0.56 at EVP 1.5 - 3.0 (significant in 5/6 observers). The specificity decreased from 0.96 to 0.90 (significant in 6/6), and the Az value and interobserver correlation increased from 0.66 to 0.74 and 0.39 to 0.48, respectively. Above the diaphragm, the median sensitivity for artificial opacities (136/276 regions) increased from 0.71 to 0.77 - 0.82 with EVP (significant in 4/6 observers). The specificity and Az value decreased from 0.76 to 0.62 and 0.74 to 0.70, respectively, (significant in 3/6). Conclusion: In this ex vivo experiment, EVP improved the diagnostic accuracy for artificial air space opacities in the superimposed parts of the lung (area under the ROC curve). Above the diaphragm, the accuracy was not affected due to a tradeoff in sensitivity/specificity. (orig.)

  18. Reduction of digital errors of digital charge division type position-sensitive detectors

    International Nuclear Information System (INIS)

    Uritani, A.; Yoshimura, K.; Takenaka, Y.; Mori, C.

    1994-01-01

    It is well known that ''digital errors'', i.e. differential non-linearity, appear in a position profile of radiation interactions when the profile is obtained with a digital charge-division-type position-sensitive detector. Two methods are presented to reduce the digital errors. They are the methods using logarithmic amplifiers and a weighting function. The validities of these two methods have been evaluated mainly by computer simulation. These methods can considerably reduce the digital errors. The best results are obtained when both methods are applied. ((orig.))

  19. A digital gain stabilizer for large volume organic scintillation detectors

    International Nuclear Information System (INIS)

    Braunsfurth, J.; Geske, K.

    1976-01-01

    A digital gain stabilizer is described, optimized for use with photomultipliers mounted on large volume organic scintillators, or other radiation detectors, which exhibit no prominent peaks in their amplitude spectra. As applications of this kind usually involve many phototubes or detectors, circuit simplicity, production reproduceability, and the possibility of computer controlled operation were major design criteria. Two versions were built, the first one using standard TTL-SSI and MSI circuitry, the second one - to reduce power requirements - using a mixture of TTL- and CMOS-LSI circuits. (Auth.)

  20. Evaluation of diagnostic accuracy of conventional and digital periapical radiography, panoramic radiography, and cone-beam computed tomography in the assessment of alveolar bone loss

    Directory of Open Access Journals (Sweden)

    Wilton Mitsunari Takeshita

    2014-01-01

    Full Text Available Background: To evaluate the diagnostic accuracy of different radiographic methods in the assessment of proximal alveolar bone loss (ABL. Materials and Methods: ABL, the distance between cement-enamel junction and alveolar bone crest, was measured in 70 mandibular human teeth - directly on the mandibles (control, using conventional periapical radiography with film holders (Rinn XCP and Han-Shin, digital periapical radiography with complementary metal-oxide semiconductor sensor, conventional panoramic, and cone-beam computed tomography (CBCT. Three programs were used to measure ABL on the images: Image tool 3.0 (University of Texas Health Sciences Center, San Antonio, Texas, USA, Kodak Imaging 6.1 (Kodak Dental Imaging 6.1, Carestream Health ® , Rochester, NY, USA, and i-CAT vision 1.6.20. Statistical analysis used ANOVA and Tukey′s test at 5% significance level. Results: The tomographic images showed the highest means, whereas the lowest were found for periapical with Han-Shin. Controls differed from periapical with Han-Shin (P < 0.0001. CBCT differed from panoramic (P = 0.0130, periapical with Rinn XCP (P = 0.0066, periapical with Han-Shin (P < 0.0001, and digital periapical (P = 0.0027. Conventional periapicals with film holders differed from each other (P = 0.0007. Digital periapical differed from conventional periapical with Han-Shin (P = 0.0004. Conclusions: Conventional periapical with Han-Shin film holder was the only method that differed from the controls. CBCT had the closest means to the controls.

  1. Design of the digitizing beam position limit detector

    International Nuclear Information System (INIS)

    Merl, R.

    1998-01-01

    The Digitizing Beam Position Limit Detector (DBPLD) is designed to identify and react to beam missteering conditions in the Advanced Photon Source (APS) storage ring. The high power of the insertion devices requires these missteering conditions to result in a beam abort in less than 2 milliseconds. Commercially available beam position monitors provide a voltage proportional to beam position immediately upstream and downstream of insertion devices. The DBPLD is a custom VME board that digitizes these voltages and interrupts the heartbeat of the APS machine protection system when the beam position exceeds its trip limits

  2. Common Positioning Errors in Digital Panoramic Radiographies Taken In Mashhad Dental School

    Directory of Open Access Journals (Sweden)

    Ali Bagherpour

    2018-06-01

    Full Text Available Introduction: The present study was aimed at evaluating common positioning errors on panoramic radiographs taken in the Radiology Department of Mashhad Dental School. Materials and methods: The study sample included 1,990 digital panoramic radiographs taken in the Radiology Department of Mashhad Dental School by a Planmeca Promax (Planmeca Oy, Helsinki, Finland, during a 2-year period (2010–2012. All radiographs, according to dentition and sex, were evaluated for positioning errors. Results: There were 1,927 (96.8% panoramic radiographs with one or more errors. While the number of errors in each image varied between one and five, most images had one error (48.4%. The most common error was that the tongue was not in contact with the hard palate (94.8%. "Open lips" was an error not seen in any patients. Conclusions:positioning errors are common in panoramic radiographies. The most common error observed in this study was a failure to place the tongue on the palate. This error and the other errors reported in this study can be reduced by training the technicians and spending little more time for patient positioning and more effective communication with the patients.

  3. Nodule detection in digital chest radiography: Summary of the radius chest trial

    International Nuclear Information System (INIS)

    Haakansson, M.; Baath, M.; Boerjesson, S.; Kheddache, S.; Grahn, A.; Ruschin, M.; Tingberg, A.; Mattson, S.; Maansson, L. G.

    2005-01-01

    As a part of the Europe-wide research project 'Unification of physical and clinical requirements for medical X-ray imaging' - governed by the Radiological Imaging Unification Strategies (RADIUS) Group - a major image quality trial was conducted by members of the group. The RADIUS chest trial aimed at thoroughly examining various aspects of nodule detection in digital chest radiography, such as the effects of nodule location, system noise, anatomical noise, and anatomical background. The main findings of the RADIUS chest trial concerning the detection of a lung nodule with a size in the order of 10 mm can be summarised as: (1) the detectability of the nodule is largely dependent on its location in the chest, (2) the system noise has a minor impact on the detectability at the dose levels used today, (3) the disturbance of the anatomical noise is larger than that of the system noise but smaller than that of the anatomical background and (4) the anatomical background acts as noise to a large extent and is the major image component affecting the detectability of the nodule. (authors)

  4. Digital pulse shape discrimination of detector data using fuzzy clustering

    International Nuclear Information System (INIS)

    Kumar, Abhinav; Chatterjee, A.; Ramachandran, K.; Shrivastava, A.; Mahata, K.

    2011-01-01

    In accelerator based experiments, data acquisition is done by CAMAC, VME and other systems. The current trend is to digitize the pulse shapes and not just the peak heights of all the input channels, by means of Flash ADCs. In view of the large number of channels involved, this leads to unprecedented data volumes. Therefore, attempts to perform a first level of analysis in real time using algorithms implemented in FPGA have become important. In the present work, digital pulse shape discrimination using fuzzy clustering has been investigated. The attempt has been to devise general purpose PSD Techniques, loosely coupled with the characteristics of detector or particle type, for particle identification. The method is applicable to neutron-gamma discrimination for liquid scintillators and charged particles detected by Si detectors

  5. Digital position sensitive discrimination for 2-dimensional scintillation detectors

    International Nuclear Information System (INIS)

    Engels, R.; Reinartz, R.; Reinhart, P.

    1996-01-01

    The energy sensitivity of a two-dimensional scintillation gamma detector based on position sensitive photomultipliers has been minimized by a digital differential discrimination unit. Since the photomultiplier gain is position-dependent by 50%, a discrimination unit has been developed where digital upper and lower discrimination levels are set due to the position-dependent photomultiplier gain obtained from calibration measurements. Depending on the spatial resolution there can be up to 65.536 position-sensitive discriminator levels defining energy windows. By this method, narrow discriminator windows can be used for reducing the low and high energy quanta without effecting the sensitivity of the detector. The new discrimination method, its performance and test measurements with gamma rays will be described. Furthermore experimental results are presented

  6. Free software for performing physical analysis of systems for digital radiography and mammography

    Energy Technology Data Exchange (ETDEWEB)

    Donini, Bruno; Lanconelli, Nico, E-mail: nico.lanconelli@unibo.it [Alma Mater Studiorum, Department of Physics and Astronomy, University of Bologna, Bologna 40127 (Italy); Rivetti, Stefano [Fisica Medica, Ospedale di Sassuolo S.p.A., Sassuolo 41049 (Italy); Bertolini, Marco [Medical Physics Unit, Azienda Ospedaliera ASMN, Istituto di Ricovero e Cura a Carattere Scientifico, Reggio Emilia 42123 (Italy)

    2014-05-15

    Purpose: In this paper, the authors present a free software for assisting users in achieving the physical characterization of x-ray digital systems and image quality checks. Methods: The program was developed as a plugin of a well-known public-domain suite ImageJ. The software can assist users in calculating various physical parameters such as the response curve (also termed signal transfer property), modulation transfer function (MTF), noise power spectra (NPS), and detective quantum efficiency (DQE). It also includes the computation of some image quality checks: defective pixel analysis, uniformity, dark analysis, and lag. Results: The software was made available in 2009 and has been used during the last couple of years by many users who gave us valuable feedback for improving its usability. It was tested for achieving the physical characterization of several clinical systems for digital radiography and mammography. Various published papers made use of the outcomes of the plugin. Conclusions: This software is potentially beneficial to a variety of users: physicists working in hospitals, staff working in radiological departments, such as medical physicists, physicians, engineers. The plugin, together with a brief user manual, are freely available and can be found online ( http://www.medphys.it/downloads.htm ). With our plugin users can estimate all three most important parameters used for physical characterization (MTF, NPS, and also DQE). The plugin can run on any operating system equipped with ImageJ suite. The authors validated the software by comparing MTF and NPS curves on a common set of images with those obtained with other dedicated programs, achieving a very good agreement.

  7. Acceptance testing and commissioning of Kodak Directview CR-850 digital radiography system.

    Science.gov (United States)

    Bezak, E; Nelligan, R A

    2006-03-01

    This Technical Paper describes Acceptance Testing and Commissioning of the Kodak DirectView CR-850 digital radiography system installed at the Royal Adelaide Hospital. The first of its type installed in Australia, the system is a "dry" image processor, for which no chemicals are required to develop images. Rather, latent radiographic images are stored on photostimulable phosphor screens, which are scanned and displayed by a reader unit. The image can be digitally processed and enhanced before it is forwarded to a storage device, printer or workstation display, thereby alleviating the need to re-expose patients to achieve satisfactory quality images. The phosphor screens are automatically erased, ready for re-use. Results are reported of tests carried out using the optional "Total Quality Tool" quality assurance package installed with the system. This package includes analysis and reporting software which provides for simple testing and reporting of many important characteristics of the system, such as field uniformity, aspect ratio, line and pixel positions, image and system noise, exposure response, scan linearity, modulation transfer function (MTF) and image artefacts. Acceptance Tests were performed for kV and MV exposures. Resolution for MV exposures was at least 0.8 l/mm, and measured phantom dimensions were within 1.05% of expected magnification. Reproducibility between cassettes was within 1.6%. The mean pixel values on the central axis were close to linear for MV exposures from 3 to 10 MU and reached saturation level at around 20 MU for 6 MV and around 30 MV for 23 MV beams. Noise levels were below 0.2 %.

  8. Free software for performing physical analysis of systems for digital radiography and mammography.

    Science.gov (United States)

    Donini, Bruno; Rivetti, Stefano; Lanconelli, Nico; Bertolini, Marco

    2014-05-01

    In this paper, the authors present a free software for assisting users in achieving the physical characterization of x-ray digital systems and image quality checks. The program was developed as a plugin of a well-known public-domain suite ImageJ. The software can assist users in calculating various physical parameters such as the response curve (also termed signal transfer property), modulation transfer function (MTF), noise power spectra (NPS), and detective quantum efficiency (DQE). It also includes the computation of some image quality checks: defective pixel analysis, uniformity, dark analysis, and lag. The software was made available in 2009 and has been used during the last couple of years by many users who gave us valuable feedback for improving its usability. It was tested for achieving the physical characterization of several clinical systems for digital radiography and mammography. Various published papers made use of the outcomes of the plugin. This software is potentially beneficial to a variety of users: physicists working in hospitals, staff working in radiological departments, such as medical physicists, physicians, engineers. The plugin, together with a brief user manual, are freely available and can be found online (www.medphys.it/downloads.htm). With our plugin users can estimate all three most important parameters used for physical characterization (MTF, NPS, and also DQE). The plugin can run on any operating system equipped with ImageJ suite. The authors validated the software by comparing MTF and NPS curves on a common set of images with those obtained with other dedicated programs, achieving a very good agreement.

  9. Effectiveness of digital subtraction radiography in detecting artificially created osteophytes and erosions in the temporomandibular joint

    Energy Technology Data Exchange (ETDEWEB)

    Kocasarac, Husniye Demirturk [Dept. of Comprehensive Dentistry, The University of Texas Health Science Center, San Antonio (United States); Celenk, Peruze [Dept. of Oral and Maxillofacial Radiology, Faculty of Dentistry, Ondokuz Mayis University, Samsun (Turkmenistan)

    2017-06-15

    Erosions and osteophytes are radiographic characteristics that are found in different stages of temporomandibular joint (TMJ) osteoarthritis. This study assessed the effectiveness of digital subtraction radiography (DSR) in diagnosing simulated osteophytes and erosions in the TMJ. Five intact, dry human skulls were used to assess the effectiveness of DSR in detecting osteophytes. Four cortical bone chips of varying thicknesses (0.5 mm, 1.0 mm, 1.5 mm, and 2.0 mm) were placed at the medial, central, and lateral aspects of the condyle anterior surface. Two defects of varying depth (1.0 mm and 1.5 mm) were created on the lateral, central, and medial poles of the condyles of 2 skulls to simulate erosions. Panoramic images of the condyles were acquired before and after artificially creating the changes. Digital subtraction was performed with Emago dental image archiving software. Five observers familiar with the interpretation of TMJ radiographs evaluated the images. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic accuracy of the imaging methods. The area under the ROC curve (Az) value for the overall diagnostic accuracy of DSR in detecting osteophytic changes was 0.931. The Az value for the overall diagnostic accuracy of panoramic imaging was 0.695. The accuracy of DSR in detecting erosive changes was 0.854 and 0.696 for panoramic imaging. DSR was remarkably more accurate than panoramic imaging in detecting simulated osteophytic and erosive changes. The accuracy of panoramic imaging in detecting degenerative changes was significantly lower than the accuracy of DSR (P<.05). DSR improved the accuracy of detection using panoramic images.

  10. Free software for performing physical analysis of systems for digital radiography and mammography

    International Nuclear Information System (INIS)

    Donini, Bruno; Lanconelli, Nico; Rivetti, Stefano; Bertolini, Marco

    2014-01-01

    Purpose: In this paper, the authors present a free software for assisting users in achieving the physical characterization of x-ray digital systems and image quality checks. Methods: The program was developed as a plugin of a well-known public-domain suite ImageJ. The software can assist users in calculating various physical parameters such as the response curve (also termed signal transfer property), modulation transfer function (MTF), noise power spectra (NPS), and detective quantum efficiency (DQE). It also includes the computation of some image quality checks: defective pixel analysis, uniformity, dark analysis, and lag. Results: The software was made available in 2009 and has been used during the last couple of years by many users who gave us valuable feedback for improving its usability. It was tested for achieving the physical characterization of several clinical systems for digital radiography and mammography. Various published papers made use of the outcomes of the plugin. Conclusions: This software is potentially beneficial to a variety of users: physicists working in hospitals, staff working in radiological departments, such as medical physicists, physicians, engineers. The plugin, together with a brief user manual, are freely available and can be found online ( http://www.medphys.it/downloads.htm ). With our plugin users can estimate all three most important parameters used for physical characterization (MTF, NPS, and also DQE). The plugin can run on any operating system equipped with ImageJ suite. The authors validated the software by comparing MTF and NPS curves on a common set of images with those obtained with other dedicated programs, achieving a very good agreement

  11. Effectiveness of digital subtraction radiography in detecting artificially created osteophytes and erosions in the temporomandibular joint

    International Nuclear Information System (INIS)

    Kocasarac, Husniye Demirturk; Celenk, Peruze

    2017-01-01

    Erosions and osteophytes are radiographic characteristics that are found in different stages of temporomandibular joint (TMJ) osteoarthritis. This study assessed the effectiveness of digital subtraction radiography (DSR) in diagnosing simulated osteophytes and erosions in the TMJ. Five intact, dry human skulls were used to assess the effectiveness of DSR in detecting osteophytes. Four cortical bone chips of varying thicknesses (0.5 mm, 1.0 mm, 1.5 mm, and 2.0 mm) were placed at the medial, central, and lateral aspects of the condyle anterior surface. Two defects of varying depth (1.0 mm and 1.5 mm) were created on the lateral, central, and medial poles of the condyles of 2 skulls to simulate erosions. Panoramic images of the condyles were acquired before and after artificially creating the changes. Digital subtraction was performed with Emago dental image archiving software. Five observers familiar with the interpretation of TMJ radiographs evaluated the images. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic accuracy of the imaging methods. The area under the ROC curve (Az) value for the overall diagnostic accuracy of DSR in detecting osteophytic changes was 0.931. The Az value for the overall diagnostic accuracy of panoramic imaging was 0.695. The accuracy of DSR in detecting erosive changes was 0.854 and 0.696 for panoramic imaging. DSR was remarkably more accurate than panoramic imaging in detecting simulated osteophytic and erosive changes. The accuracy of panoramic imaging in detecting degenerative changes was significantly lower than the accuracy of DSR (P<.05). DSR improved the accuracy of detection using panoramic images

  12. Evaluation of a digital optical ionizing radiation particle track detector

    International Nuclear Information System (INIS)

    Hunter, S.R.

    1987-06-01

    An ionizing radiation particle track detector is outlined which can, in principle, determine the three-dimensional spatial distribution of all the secondary electrons produced by the passage of ionizing radiation through a low-pressure (0.1 to 10 kPa) gas. The electrons in the particle track are excited by the presence of a high-frequency AC electric field, and two digital cameras image the optical radiation produced in electronic excitation collisions of the surroundings gas by the electrons. The specific requirements of the detector for neutron dosimetry and microdosimetry are outlined (i.e., operating conditions of the digital cameras, high voltage fields, gas mixtures, etc.) along with an estimate of the resolution and sensitivity achievable with this technique. The proposed detector is shown to compare favorable with other methods for obtaining the details of the track structure, particularly in the quality of the information obtainable about the particle track and the comparative simplicity and adaptability of the detector for measuring the secondary electron track structure for many forms of ionizing radiation over a wide range of energies

  13. Phantom examination for reduction of radiation dose using new needle screen storage phosphor radiography and add beam filter in digital thoracic radiography on adolescents and larger children

    International Nuclear Information System (INIS)

    Heyne, J.P.; Mentzel, H.J.; Neumann, R.; Lopatta, E.; Zimmermann, U.; Kaiser, W.A.

    2008-01-01

    Purpose: how much can the radiation dose be reduced in thoracic radiography on adolescents and larger children by using needle screen storage phosphor (NIP) radiography and add beam filtration? Materials and methods: a chest phantom with typical anatomical structures, pathological findings, added catheters, and simulated nodules, tumors, and calcifications was X-rayed digitally (DX-S, Agfa Healthcare) in posterior-anterior (p.a.) orientation with and without add beam filter. While keeping the voltage constant, the tube current time product was reduced gradually. In addition to LgM, the surface entrance dose (ED) and the dose area product (DAP) were measured by the Dosimax sensor and Kerma X-plus (both Wellhoefer). Five investigators evaluated the images for characteristics and critical features, pathological findings, and catheter recognizability. Results: the ED of the digital chest radiogram p.a. with 115 kV and 0.71 mAs was 27 μGy, the DAP 3.6 μGy x m 2 , the LgM value 1.56. This initial radiogram was able to be evaluated very well and conforms to the quality guidelines. The dose-reduced chest radiograms with the add beam filter Al 1.0 mm/Cu 0.1 mm were evaluated as sufficiently reduced to a dose of 63% of the initial dose, with the add beam filter Al 1.0 mm/Cu 0.2 mm reduced to 50% (0.52 mAs, DAP 1.82 μGy x m 2 , LgM 1.35). P.a. radiograms were able to be X-rayed on 115 kV with 0.52 mAs. (orig.)

  14. Evaluation of conventional and digital radiography capacities for distinguishing dental materials on radiograms depending on the present radiopacifying agent.

    Science.gov (United States)

    Antonijević, Djordje; Ilić, Dragan; Medić, Vesna; Dodić, Slobodan; Obradović-Djuriĉić, Kosovka; Rakoĉević, Zoran

    2014-11-01

    The radiopacity of an endodontic material can considerably vary as measured on film and a digital sensor. Digital radiography offers numerous advantages over conventional film-based radiography in dental clinical practice regarding both diagnostic capabilities and postintervention procedures. The aim of this study was to investigate the capacity of conventional and charge-conpled device (CCD) based digital radiography to detect material on radiograph depending on the radio-pacifying agent present in the mate- rial. Experimental cements were formulated by mixing Portland cement with the following radiopacifying agents: zinc oxide (ZnO), zirconium oxide (ZrO2), titanium dioxide (TiO2), barium sulphate (BaSO4), iodoform (CHI3), bismuth oxide (Bi2O3) and ytterbium trifluoride (YbF3). In addition, 5 endodontic materials comprising Endometh- asone, Diaket, N2, Roth 801 and Acroseal were investigated to serve as control. Per three specimens of each material were radiographed alongside an aluminum step wedge on film (Eastman Kodak Company, Rochester, NY) and a CCD-based digital sensor (Trophy Radiologie, Cedex, France). Radiopacity values were calculated by converting the radiographic densities of the specimens expressed as a mean optical densities or mean grey scale values into equivalent thickness of aluminum. Two-way ANOVA detected no significant differences with respect to the imaging system (p > 0.05), but the differences were significant with respect to radiopacifier (p < 0.001) and the interaction of the two factors (p < 0.05). Paired t-test revealed significant differences between the methods used for pure Portland cement, all concentrations of BaSO4 and CHI3, 10% and 20% additions of ZrO2 and Bi2O3 and 10% and 30% additions of YbF3 (p < 0.05). The materials which incorporate CHI3 OR BaSO4 as radiopacifying agents are expected to be significantly more radiopaque on a digital sensor than on film. During clinical practice one should concern to the quality of contrast

  15. Evaluation of conventional and digital radiography capacities for distinguishing dental materials on radiograms depending on the present radiopacifying agent

    Directory of Open Access Journals (Sweden)

    Antonijević Đorđe

    2014-01-01

    Full Text Available Bacgroun/Aim. The radiopacity of an endodontic material can considerably vary as measured on film and a digital sensor. Digital radiography offers numerous advantages over convential film-based radiography in dental clinical practice regarding both diagnostic capabilities and postintervention procedures. The aim of this study was to investigate the capacity of conventional and charge-conpled device (CCD based digital radiography to detect material on radiograph depending on the radio-pacifying agent present in the material. Methods. Experimental cements were formulated by mixing Portland cement with the following radiopacifying agents: zinc oxide (ZnO, zirconium oxide (ZrO2, titanium dioxide (TiO2, barium sulphate (BaSO4, iodoform (CHI3, bismuth oxide (Bi2O3 and ytterbium trifluoride (YbF3. In addition, 5 endodontic materials comprising Endomethasone®, Diaket®, N2®, Roth 801® and Acroseal® were investigated to serve as control. Per three specimens of each material were radiographed alongside an aluminum step wedge on film (Eastman Kodak Company®, Rochester, NY and a CCD-based digital sensor (Trophy Radiologie®, Cedex, France. Radiopacity values were calculated by converting the radiographic densities of the specimens expressed as a mean optical densities or mean grey scale values into equivalent thickness of aluminum. Results. Twoway ANOVA detected no significant differences with respect to the imaging system (p > 0.05, but the differences were significant with respect to radiopacifier (p < 0.001 and the interaction of the two factors (p < 0.05. Paired ttest revealed significant differences between the methods used for pure Portland cement, all concentrations of BaSO4 and CHI3, 10% and 20% additions of ZrO2 and Bi2O3 and 10% and 30% addition of YbF3 (p < 0.05. Conclusion. The materials which incorporate CHI3 or BaSO4 as radiopacifying agents are expected to be significantly more radiopaque on a digital sensor than on film. During clinical

  16. Digital subtraction radiography evaluation of the bone repair process of chronic apical periodontitis after root canal treatment.

    Science.gov (United States)

    Benfica e Silva, J; Leles, C R; Alencar, A H G; Nunes, C A B C M; Mendonça, E F

    2010-08-01

    To monitor radiographically the progress of bone repair within chronic periapical lesions after root canal treatment using digital subtraction radiography (DSR). Twelve patients with 17 single-rooted teeth with chronic apical periodontitis associated with an infected necrotic pulp were selected for root canal treatment. Periapical radiographs were taken before treatment (baseline) and immediately post-treatment, 45, 90, 135 and 180 days after treatment. The radiographic protocol included the use of individualized film holders with silicone bite blocks. The six radiographic images were digitized and submitted to digital subtraction using DSR software, resulting in five subtracted images (SI). Quantitative analysis of these SI was performed using Image Tool software to assess pixel value changes, considering a step-wedge as the gold standard and a cut-off value of 128 pixels. The aim was to identify any increase or decrease in mineral density in the region of the periapical lesion. A minor decrease in mineral density at the canal filling session and a significant progressive mineral gain in the following evaluations (P < 0.001) occurred. Pairwise comparison of pixel grey values revealed that only the 180-day follow-up differed significantly from the previous SI. Digital subtraction radiography is a useful method for evaluating the progress of bone repair after root canal treatment. Noticeable mineral gain was observed approximately 90 days after root canal filling and definite bone repair after 180 days.

  17. Comparison of digital radiography and apex locator with the conventional method in root length determination of primary teeth

    Directory of Open Access Journals (Sweden)

    I E Neena

    2011-01-01

    Full Text Available Aim: The purpose of this study was to compare the Working length in primary teeth endodontics using intra oral digital radiovisiography and apex locator with conventional method for accuracy. Materials and Methods: This in vivo study was conducted on 30 primary teeth which were indicated for pulpectomy in the patients of the age group of 5-11 years All experimental teeth had adequate remaining tooth structure for rubber dam isolation and radiographicaly visible canals. Endodontic treatment was required due to irreversible pulpitis or pulp necrosis. A standardized intraoral periapical radiograph of the tooth was taken using conventional method by paralleling technique. The distance between the source and the tooth, tooth and the films were standardized using X-ray positioning device. During the pulpectomy procedure, the working length was determined by digital radiograph and apex locator. The measurements were then compared with the conventional method of root canal measurement technique for accuracy Result: From the results obtained we can conclude that Working length determined in primary molars using digital radiography and Apex locator did not show any significant difference in the mean working length measurements when compared with the conventional radiographic method. Conclusions: Apex locator is comparable to conventional radiograph in determining the working length without radiation in the primary teeth. Intraoral digital radiography is the safest method in determining the working length with significant reduction in radiation exposure.Hence, both the techniques can be safely used as alternatives to conventional radiographic methods in determining working length in primary teeth.

  18. Evaluation of chronic periapical lesions by digital subtraction radiography by using Adobe Photoshop CS: a technical report.

    Science.gov (United States)

    Carvalho, Fabiola B; Gonçalves, Marcelo; Tanomaru-Filho, Mário

    2007-04-01

    The purpose of this study was to describe a new technique by using Adobe Photoshop CS (San Jose, CA) image-analysis software to evaluate the radiographic changes of chronic periapical lesions after root canal treatment by digital subtraction radiography. Thirteen upper anterior human teeth with pulp necrosis and radiographic image of chronic periapical lesion were endodontically treated and radiographed 0, 2, 4, and 6 months after root canal treatment by using a film holder. The radiographic films were automatically developed and digitized. The radiographic images taken 0, 2, 4, and 6 months after root canal therapy were submitted to digital subtraction in pairs (0 and 2 months, 2 and 4 months, and 4 and 6 months) choosing "image," "calculation," "subtract," and "new document" tools from Adobe Photoshop CS image-analysis software toolbar. The resulting images showed areas of periapical healing in all cases. According to this methodology, the healing or expansion of periapical lesions can be evaluated by means of digital subtraction radiography by using Adobe Photoshop CS software.

  19. Scatter correction method with primary modulator for dual energy digital radiography: a preliminary study

    Science.gov (United States)

    Jo, Byung-Du; Lee, Young-Jin; Kim, Dae-Hong; Jeon, Pil-Hyun; Kim, Hee-Joung

    2014-03-01

    In conventional digital radiography (DR) using a dual energy subtraction technique, a significant fraction of the detected photons are scattered within the body, resulting in the scatter component. Scattered radiation can significantly deteriorate image quality in diagnostic X-ray imaging systems. Various methods of scatter correction, including both measurement and non-measurement-based methods have been proposed in the past. Both methods can reduce scatter artifacts in images. However, non-measurement-based methods require a homogeneous object and have insufficient scatter component correction. Therefore, we employed a measurement-based method to correct for the scatter component of inhomogeneous objects from dual energy DR (DEDR) images. We performed a simulation study using a Monte Carlo simulation with a primary modulator, which is a measurement-based method for the DEDR system. The primary modulator, which has a checkerboard pattern, was used to modulate primary radiation. Cylindrical phantoms of variable size were used to quantify imaging performance. For scatter estimation, we used Discrete Fourier Transform filtering. The primary modulation method was evaluated using a cylindrical phantom in the DEDR system. The scatter components were accurately removed using a primary modulator. When the results acquired with scatter correction and without correction were compared, the average contrast-to-noise ratio (CNR) with the correction was 1.35 times higher than that obtained without correction, and the average root mean square error (RMSE) with the correction was 38.00% better than that without correction. In the subtraction study, the average CNR with correction was 2.04 (aluminum subtraction) and 1.38 (polymethyl methacrylate (PMMA) subtraction) times higher than that obtained without the correction. The analysis demonstrated the accuracy of scatter correction and the improvement of image quality using a primary modulator and showed the feasibility of

  20. Comparison of Digital Tomosynthesis and Chest Radiography for the Detection of Noncalcified Pulmonary and Hilar Lesions.

    Science.gov (United States)

    Galea, Angela; Adlan, Tarig; Gay, David; Roobottom, Carl; Dubbins, Paul; Riordan, Richard

    2015-09-01

    The aim of this study was to compare the sensitivity and specificity of chest digital tomosynthesis (DTS) with chest radiography (CXR) for the detection of noncalcified pulmonary nodules and hilar lesions using computed tomography (CT) as the reference standard. A total of 78 patients with suspected noncalcified pulmonary lesions on CXR were included in the study. Two radiologists, blinded to the history and CT, analyzed the CXR and the DTS images (separately), whereas a third radiologist analyzed the CXR and DTS images together. Noncalcified intrapulmonary nodules and hilar lesions were recorded for analysis. The interobserver agreement for CXR and DTS was assessed, and the time taken to report the images was recorded. A total of 202 lesions were recorded in 78 patients. There were 111 true lesions confirmed on CT in 53 patients; in 25 patients subsequent CT excluded a lesion. The overall sensitivity was 32% for CXR and 49% for DTS. This improved to 54% when the posteroanterior CXR and DTS were reviewed together (CXR-DTS). The overall specificities for CXR, DTS, and CXR-DTS were 49%, 96%, and 98%, respectively. There were 56 suspected hilar lesions with subgroup sensitivities of 76% for CXR, 65% for DTS, and 76% for CXR-DTS. The specificity for hilar lesions was 59%, 92%, and 97% for CXR, DTS, and CXR-DTS, respectively. DTS significantly improves the detectability of noncalcified nodules when compared with and when used in combination with CXR. The specificity and interobserver agreement of DTS in the diagnosis of suspected noncalcified pulmonary nodules and hilar lesions are significantly better than those of CXR and approaches those of CT.

  1. Local liquid velocity measurement of Trickle Bed Reactor using Digital Industrial X-ray Radiography

    Science.gov (United States)

    Mohd Salleh, Khairul Anuar

    Trickle Bed Reactors (TBRs) are fixed beds of particles in which both liquid and gas flow concurrently downward. They are widely used to produce not only fuels but also lubrication products. The measurement and the knowledge of local liquid velocities (VLL) in TBRs is less which is essential for advancing the understanding of its hydrodynamics and for validation computational fluid dynamics (CFD). Therefore, this work focused on developing a new, non-invasive, statistically reliable technique that can be used to measure local liquid velocity (VLL) in two-dimensions (2-D). This is performed by combining Digital Industrial X-ray Radiography (DIR) and Particle Tracking Velocimetry (PTV) techniques. This work also make possible the development of three-dimensional (3-D) VLL measurements that can be taken in TBRs. Measurements taken through both the combined and the novel technique, once validated, were found to be comparable to another technique (a two-point fiber optical probe) currently being developed at Missouri University of Science and Technology. The results from this study indicate that, for a gas-liquid-solid type bed, the measured VLL can have a maximum range that is between 35 and 51 times that of its superficial liquid velocity (VSL). Without the existence of gas, the measured VLL can have a maximum range that is between 4 and 4.7 times that of its VSL. At a higher V SL, the particle tracer was greatly distributed and became carried away by a high liquid flow rate. Neither the variance nor the range of measured VLL varied for any of the replications, confirming the reproducibility of the experimental measurements used, regardless of the VSL . The liquid's movement inside the pore was consistent with findings from previous studies that used various techniques.

  2. CT urography of urinary diversions with enhanced CT digital radiography: preliminary experience.

    Science.gov (United States)

    Sudakoff, Gary S; Guralnick, Michael; Langenstroer, Peter; Foley, W Dennis; Cihlar, Krista L; Shakespear, Jonathan S; See, William A

    2005-01-01

    The purpose of this study was to determine if 3D-rendered CT urography (CTU) depicts both normal and abnormal findings in patients with urinary diversions and if the addition of contrast-enhanced CT digital radiography (CTDR) improves opacification of the urinary collecting system. Thirty CTU and contrast-enhanced CTDR examinations were performed in 24 patients who underwent cystectomy for bladder cancer. Indications for evaluation included hematuria, tumor surveillance, or suspected diversion malfunction. All examinations were evaluated without knowledge of the stage or grade of a patient's tumor and were compared with the clinical records. Opacification of the urinary collecting system was evaluated with 3D CTU alone, contrast-enhanced CTDR alone, and combined CTU and CTDR. Nine abnormalities were identified including distal ureteral strictures (n = 4), vascular compression of the mid left ureter (n = 1), scarring of the mid right pole infundibulum (n = 1), bilateral hydronephrosis and hydroureter (n = 1), urinary reservoir calculus (n = 1), and tumor recurrence invading the afferent limb of the neobladder (n = 1). Eight of the nine detected abnormalities were surgically or pathologically confirmed. All abnormalities were identified on all three imaging techniques but were best seen on 3D CTU and enhanced CTDR images. Incomplete opacification of the urinary collecting system occurred in 17 patients with CTU alone, 12 patients with contrast-enhanced CTDR alone, and nine patients with combined CTU and contrast-enhanced CTDR. Compared with CTU alone, the combined technique of 3D CTU and contrast-enhanced CTDR improved opacification by a statistically significant difference (p = 0.037). CTU with 3D rendering can accurately depict both normal and abnormal postoperative findings in patients with urinary diversions. Adding enhanced CTDR can improve visualization of the urinary collecting system.

  3. Assessment of digital panoramic radiography's diagnostic value in angular bony lesions with 5 mm or deeper pocket depth in mandibular molars

    Directory of Open Access Journals (Sweden)

    Bardia Vadiati Saberi

    2017-01-01

    Conclusion: Based on this study, bone probing is a reliable method in vertical alveolar bone defect measurements. While the information obtained from digital panoramic radiographs should be used with caution and the ability of digital panoramic radiography in the determination of defect depth is limited.

  4. Estimating pediatric entrance skin dose from digital radiography examination using DICOM metadata: A quality assurance tool

    Energy Technology Data Exchange (ETDEWEB)

    Brady, S. L., E-mail: samuel.brady@stjude.org; Kaufman, R. A., E-mail: robert.kaufman@stjude.org [Department of Diagnostic Imaging, St. Jude Children’s Research Hospital, Memphis, Tennessee 38105 (United States)

    2015-05-15

    Purpose: To develop an automated methodology to estimate patient examination dose in digital radiography (DR) imaging using DICOM metadata as a quality assurance (QA) tool. Methods: Patient examination and demographical information were gathered from metadata analysis of DICOM header data. The x-ray system radiation output (i.e., air KERMA) was characterized for all filter combinations used for patient examinations. Average patient thicknesses were measured for head, chest, abdomen, knees, and hands using volumetric images from CT. Backscatter factors (BSFs) were calculated from examination kVp. Patient entrance skin air KERMA (ESAK) was calculated by (1) looking up examination technique factors taken from DICOM header metadata (i.e., kVp and mA s) to derive an air KERMA (k{sub air}) value based on an x-ray characteristic radiation output curve; (2) scaling k{sub air} with a BSF value; and (3) correcting k{sub air} for patient thickness. Finally, patient entrance skin dose (ESD) was calculated by multiplying a mass–energy attenuation coefficient ratio by ESAK. Patient ESD calculations were computed for common DR examinations at our institution: dual view chest, anteroposterior (AP) abdomen, lateral (LAT) skull, dual view knee, and bone age (left hand only) examinations. Results: ESD was calculated for a total of 3794 patients; mean age was 11 ± 8 yr (range: 2 months to 55 yr). The mean ESD range was 0.19–0.42 mGy for dual view chest, 0.28–1.2 mGy for AP abdomen, 0.18–0.65 mGy for LAT view skull, 0.15–0.63 mGy for dual view knee, and 0.10–0.12 mGy for bone age (left hand) examinations. Conclusions: A methodology combining DICOM header metadata and basic x-ray tube characterization curves was demonstrated. In a regulatory era where patient dose reporting has become increasingly in demand, this methodology will allow a knowledgeable user the means to establish an automatable dose reporting program for DR and perform patient dose related QA testing for

  5. Computed radiography

    International Nuclear Information System (INIS)

    Pupchek, G.

    2004-01-01

    Computed radiography (CR) is an image acquisition process that is used to create digital, 2-dimensional radiographs. CR employs a photostimulable phosphor-based imaging plate, replacing the standard x-ray film and intensifying screen combination. Conventional radiographic exposure equipment is used with no modification required to the existing system. CR can transform an analog x-ray department into a digital one and eliminates the need for chemicals, water, darkrooms and film processor headaches. (author)

  6. Pulsed X-ray radiography of a gas jet target for laser-matter interaction experiments with the use of a CCD detector

    International Nuclear Information System (INIS)

    Rakowski, R.; Bartnik, A.; Fiedorowicz, H.; Jarocki, R.; Kostecki, J.; MikoIajczyk, J.; Szczurek, A.; Szczurek, M.; Foeldes, I.B.; Toth, Zs.

    2005-01-01

    Characterization of gas jet targets has been carried out using pulsed X-ray radiography. A laser-plasma X-ray source was applied for backlighting of the targets to obtain X-ray shadowgraphs registered with a CCD detector. From the shadowgraphs, characteristics of the targets were determined

  7. Accuracy of digital radiography and cone beam computed tomography on periapical radiolucency detection in endodontically treated teeth.

    Science.gov (United States)

    Venskutonis, Tadas; Daugela, Povilas; Strazdas, Marijus; Juodzbalys, Gintaras

    2014-04-01

    The aim of the present study was to compare the accuracy of intraoral digital periapical radiography and cone beam computed tomography in the detection of periapical radiolucencies in endodontically treated teeth. Radiographic images (cone beam computed tomography [CBCT] scans and digital periapical radiography [PR] images) from 60 patients, achieved from September 2008 to July 2013, were retrieved from databases of the Department of Oral Diseases, Lithuanian University of Health Sciences. Twenty patients met inclusion criteria and were selected for further evaluation. In 20 patients (42.4 [SD 12.1] years, 65% men and 35% women) a total of 35 endodontically treated teeth (1.75 [SD 0.91]; 27 in maxilla and 8 in mandible) were evaluated. Overall, it was observed a statistical significant difference between the number of periapical lesions observed in the CBCT (n = 42) and radiographic (n = 24) examinations (P cone beam computed tomography scans were more accurate compared to digital periapical radiographs for detecting periapical radiolucencies in endodontically treated teeth. The difference was more pronounced in molar teeth.

  8. Diagnostic Value of Conventional and Digital Radiography for Detection of Cavitated and Non-Cavitated Proximal Caries

    Directory of Open Access Journals (Sweden)

    Mahdieh Dehghani

    2017-02-01

    Full Text Available Objectives: This study aimed to assess the diagnostic value of conventional and digital radiography for detection of cavitated and non-cavitated proximal caries.Materials and Methods: Fifty extracted human premolars and molars were mounted in a silicone block. Charge-coupled device (CCD and photostimulable phosphor plate (PSP receptors and intra-oral films were exposed with 60 and 70 kVp with parallel technique. Two observers interpreted the radiographs twice with a two-week interval using a 5-point scale. Teeth were then serially sectioned in mesiodistal direction and evaluated under a stereomicroscope (gold standard. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy were calculated.Results: Sensitivity of all three receptors for detection of enamel lesions was low (5.5-44.4% but it was higher for dentin lesions (42.8-62.8%; PSP with 70 kVp and 0.03s exposure time had the highest sensitivity for enamel lesions, but the difference among receptors was not statistically significant (P>0.05. Sensitivity of all three receptors for detection of non-cavitated lesions was lower than that for cavitated lesions; PSP with 60 kVp and 0.07s exposure time had higher sensitivity and lower patient radiation dose for detection of cavitated and non-cavitated lesions, but the difference was not significant (P>0.05.Conclusions: Digital radiography using PSP receptor with 70 kVp is recommended to detect initial enamel caries. For detection of non-cavitated and cavitated dentin caries, PSP with 60 kVp is more appropriate. Change in kVp did not affect the diagnostic accuracy for detection of caries, and type of receptor was a more important factor.Keywords: Dental Caries; Diagnostic Imaging; Radiography, Dental, Digital

  9. Scatter correction using a primary modulator for dual energy digital radiography: A Monte Carlo simulation study

    Science.gov (United States)

    Jo, Byung-Du; Lee, Young-Jin; Kim, Dae-Hong; Kim, Hee-Joung

    2014-08-01

    In conventional digital radiography (DR) using a dual energy subtraction technique, a significant fraction of the detected photons are scattered within the body, making up the scatter component. Scattered radiation can significantly deteriorate image quality in diagnostic X-ray imaging systems. Various methods of scatter correction, including both measurement- and non-measurement-based methods, have been proposed in the past. Both methods can reduce scatter artifacts in images. However, non-measurement-based methods require a homogeneous object and have insufficient scatter component correction. Therefore, we employed a measurement-based method to correct for the scatter component of inhomogeneous objects from dual energy DR (DEDR) images. We performed a simulation study using a Monte Carlo simulation with a primary modulator, which is a measurement-based method for the DEDR system. The primary modulator, which has a checkerboard pattern, was used to modulate the primary radiation. Cylindrical phantoms of variable size were used to quantify the imaging performance. For scatter estimates, we used discrete Fourier transform filtering, e.g., a Gaussian low-high pass filter with a cut-off frequency. The primary modulation method was evaluated using a cylindrical phantom in the DEDR system. The scatter components were accurately removed using a primary modulator. When the results acquired with scatter correction and without scatter correction were compared, the average contrast-to-noise ratio (CNR) with the correction was 1.35 times higher than that obtained without the correction, and the average root mean square error (RMSE) with the correction was 38.00% better than that without the correction. In the subtraction study, the average CNR with the correction was 2.04 (aluminum subtraction) and 1.38 (polymethyl methacrylate (PMMA) subtraction) times higher than that obtained without the correction. The analysis demonstrated the accuracy of the scatter correction and the

  10. Diagnosis of the depth of invasion of esophageal carcinoma using digital radiography

    International Nuclear Information System (INIS)

    Ito, Bunichi; Niwa, Yasumasa; Ando, Nobuhiro; Ohmiya, Naoki; Miyahara, Ryoji; Ohashi, Akira; Itoh, Akihiro; Hirooka, Yoshiki; Goto, Hidemi

    2005-01-01

    Objective: The purpose of our investigation was to determine the usefulness of digital radiography (DR) for diagnosing the depth of invasion of esophageal carcinoma. Methods: We evaluated 59 patients with esophageal carcinomas who underwent DR. During continuous DR in tangential views, the most distended image of the esophagus was chosen. Percent esophageal stenosis (PES) was based on the diameter across the lesion of maximal narrowing and the average of the normal oral and anal side diameters. The maximal thickness of the tumor was measured on sequentially prepared specimens. We evaluated whether the percent of esophageal stenosis correlated with the maximal thickness of the tumor on histologic findings. Receiver-operating characteristic (ROC) curves were constructed to establish the cut-off level for PES in diagnosing the depth of tumor invasion. Accuracies for the depth of the invasion were calculated based on PES using DR. For the accuracy rate, DR was compared with endoscopy and endoscopic ultrasonography (EUS). Results: There was a close correlation between PES and pathological thickness of the tumor. PES values (mean ± S.D.) were 2.45 ± 0.75% in Tis and T1a tumors, 13.3 ± 10.9% in T1b tumors, 35.2 ± 11.1% in T2 tumors, 55.2 ± 18.1% in T3 tumors, and 86.1 ± 7.5% in T4 tumors. Using the ROC analysis, 12.5, 37.5, and 44.4% were the highest cut-off values of PES for differentiating ≤T1a, ≤T1b, and ≤T2 tumors. Regarding T staging, 45 (76%) of 59 lesions were staged correctly with EUS, whereas 47 (80%) were staged correctly with DR. Conclusion: DR is useful for diagnosing the depth of the invasion because esophageal stenosis calculated using DR is an objective index of tumor infiltration. The accuracy rate of the depth of invasion with DR was as good as that of EUS

  11. Discriminated neutron and X-ray radiography using multi-color scintillation detector

    International Nuclear Information System (INIS)

    Nittoh, Koichi; Takahara, Takeshi; Yoshida, Tadashi; Tamura, Toshiyuki

    1999-01-01

    A new conversion screen Gd 2 O 2 S:Eu is developed, which emits red light on irradiation by thermal neutrons. By applying this in combination with the currently used Gd 2 O 2 S:Tb, a green-light scintillator, in the radiography under a neutron + X-ray coexisting field, we can easily separate the neutron image and the X-ray image by simple color-image processing. This technique enables a non-destructive and detailed inspection of industrial products composed both of light elements (water, plastics, etc.) and heavy elements (metals), widening the horizon of new applications

  12. Discriminated neutron and X-ray radiography using multi-color scintillation detector

    CERN Document Server

    Nittoh, K; Yoshida, T; Tamura, T

    1999-01-01

    A new conversion screen Gd sub 2 O sub 2 S:Eu is developed, which emits red light on irradiation by thermal neutrons. By applying this in combination with the currently used Gd sub 2 O sub 2 S:Tb, a green-light scintillator, in the radiography under a neutron + X-ray coexisting field, we can easily separate the neutron image and the X-ray image by simple color-image processing. This technique enables a non-destructive and detailed inspection of industrial products composed both of light elements (water, plastics, etc.) and heavy elements (metals), widening the horizon of new applications.

  13. Reduction of radiation dose by using digital luminescence radiography compared to conventional screen film system with grid cassette

    International Nuclear Information System (INIS)

    Heyne, J.P.; Merbold, H.; Neumann, R.; Freesmeyer, M.; Jonetz-Mentzel, L.; Kaiser, W.A.; Sehner, J.

    1999-01-01

    Purpose: How much can the radiation dose be reduced for skull radiography by using digital luminescence radiography (DLR) compared to a conventional screen film system with a grid cassette? Methods and Materials: A skull phantom (3M) was X-rayed in anterior-posterior orientation using both a conventional screen film system with grid cassette and DLR (ADC-70, Agfa). The tube current time product (mAs) was diminished gradually while keeping the voltage constant. The surface entrance dose was measured by a sensor of Dosimax (Wellhoefer). Five investigators evaluated the images by characteristic and critical features, spatial resolution and contrast. Results: The surface entrance dose at 73 kV/22 mAs was 0,432 mGy in conventional screen film system and 0,435 mGy in DLR. The images could be evaluated very well down to an average dose of 71% (0,308 mGy; SD 0,050); sufficient images were obtained down to an average dose of 31% (0,136 mGy; SD 0,065). The resolution of the line pairs were reduced down to a 2 levels depending on the investigator. Contrast was assessed as being very good to sufficient. The acceptance of the postprocessed images (MUSICA-software) was individually different and resultde in an improvement of the assessment of bone structures an contrast in higher dose ranges only. Conclusion: For the sufficient assessment of a possible fracture/of paranasal sinuses/of measurement the skull the dose can be reduced to at least 56% (31%; SD 14,9%)/40% (27%; SD 9,3%)/18% (14%; SD 4,4%). Digital radiography allows question-referred exposure parameters with clearly reduced dose, so e.g. for fracture exclusion 73 kV/12,5 mAs and to skull measurement 73 kV/4 mAs. (orig.) [de

  14. Micro-XRF complemented by x-radiography and digital microscopy imaging for the study of hidden paintings

    Science.gov (United States)

    Gasanova, Svetlana; Hermon, Sorin

    2017-07-01

    The present study describes a novel approach to the study of hidden by integrating the non-invasive micro-X-Ray Fluorescence spectroscopy, X-radiography and digital microscopy. The case study analysed is a portrait of a male figure discovered under the painting of Ecce Homo, attributed to Titian's studio with an estimated date in the 1550s. The X-radiography images exposed the details of the underpainting, which appeared to be a nearly finished portrait of a standing man, overpainted by the current composition of Ecce Homo at a 180° angle. The microscopy observations of the upper painting's cracks and flaked areas enabled the study of the exposed underlayers in terms of their colour appearance and pigment particles. The subsequent pigment analysis was performed by micro-XRF. Since the described XRF analysis was performed not in scanner mode, the correct selection of the measurement spots for the micro analysis and separation between pigments of the lower and the upper painting was of paramount importance. The described approach for spot selection was based on the results of the preceding X-radiography and digital microscopy tests. The presence of lead white, vermilion, copper green and iron earth in the underlying portrait was confirmed by the multiple point XRF analysis of Pb, Hg, Cu, Fe and Mn lines. The described investigation method proved to be useful in the identification of the pigments of the underlying painting and consequently assisted in the tentative reconstruction of its colour palette. Moreover, the undertaken approach allowed discovering the potential of micro-XRF technique in the study of hidden compositions.

  15. An investigation into dental digital radiography in dental practices in West Kent following the introduction of the 2006 NHS General Dental Services contract.

    Science.gov (United States)

    Mauthe, Peter W; Eaton, Kenneth A

    2011-04-01

    The primary aims of the study were to investigate the use of digital radiography within primary dental care practices in the West Kent Primary Care Trust (PCT) area and general dental practitioners' (GDPs) self-reported change in radiographic prescribing patterns following the introduction of the nGDS contract in 2006. Data were gathered via a piloted, self-completed questionnaire, and circulated to all GDPs listed on the National Health Service (NHS) Choices website as practising in the West Kent PCT area. There were three mailings and follow-up telephone calls. The resulting data were entered into a statistical software database and, where relevant, statistically tested, using the chi-square test and Pearson correlation coefficient. Of 223 GDPs, 168 (75%) responded. There were 163 usable questionnaires. The respondents represented 85% of the general dental practices in West Kent. Eighty (49%) respondents were using digital intra-oral radiography. Of those who used digital radiography, 44 (55%) reported that they used phosphor plate systems and 36 (45%) that they used direct digital sensors. Eighty-three (51%) had a panoramic machine in their practice, 46 of whom (55%) were using digital systems; of these, 32 (67%) were using a direct digital system. Seventy-one GDPs reported that they worked exclusively or mainly in private practice. Forty (56%) of these 'mainly private' GDPs reported that they used digital radiographic systems, whereas only 40 (44%) of the 89 'mainly NHS' GDPs reported using digital radio-graphic systems. On average, mainly private GDPs made the transition to a digital radiographic system six months before mainly NHS GDPs. Of those who provided NHS dentistry before and after April 2006, only 18 (14%) reported taking fewer radiographs and seven (6%) taking more. In February 2010, of the West Kent GDPs who responded to the questionnaire, just under 50% used digital radio graphy. Mainly private GDPs were more likely to use digital radiography than

  16. Digital Tomosynthesis to Evaluate Fracture Healing: Prospective Comparison With Radiography and CT.

    Science.gov (United States)

    Ha, Alice S; Lee, Amie Y; Hippe, Daniel S; Chou, Shinn-Huey S; Chew, Felix S

    2015-07-01

    Radiography, currently the standard for postoperative fracture imaging, is limited by overlapping bone and hardware. Tomosynthesis has the benefit of level-by-level imaging without the disadvantages of metal artifacts, increased radiation, and higher costs of CT, the current problem-solving tool. The purpose of this study was to compare tomosynthesis with radiography for evaluating fracture healing. In a prospective study, patients within 1 year of wrist hardware fixation underwent radiography, tomosynthesis, and CT, and the images were interpreted by three readers. The diagnostic accuracy of radiology and tomosynthesis was assessed with ROC curves, and interreader agreement was assessed with Cohen kappa. Fracture scores were correlated with Disabilities of the Arm, Shoulder, and Hand (DASH) and pain scores. The study participants were 49 patients with 51 fractures. The most common fracture sites were distal radius (43%), scaphoid (18%), and metacarpals (18%). Rates of cortex obscuration by hardware were 2% for CT, 8% for tomosynthesis, and 15% for radiography (p tomosynthesis than with radiography (AUC, 0.84 vs 0.76, p = 0.01). Inter-reader agreement was moderate for both radiography and tomosynthesis (κ = 0.44 vs 0.55, p = 0.051). There was no significant correlation between fracture scores and DASH scores. There was significant correlation between reported pain levels and both tomosynthesis (r = 0.28, p = 0.03) and CT (r = 0.29, p = 0.04) fracture scores. Tomosynthesis provides diagnostic information superior to that of ra diography in postoperative evaluation of wrist fractures with lower cost and radiation than CT and should be considered in fracture follow-up imaging of other bones.

  17. Characterisation of Late Bronze Age large size shield nails by EDXRF, micro-EDXRF and X-ray digital radiography

    International Nuclear Information System (INIS)

    Figueiredo, E.; Araujo, M.F.; Silva, R.J.C.; Senna-Martinez, J.C.; Ines Vaz, J.L.

    2011-01-01

    In the present study six exceptional large size metallic nails, a dagger and a sickle from the Late Bronze Age archaeological site of Figueiredo das Donas (Central Portugal) have been analysed by EDXRF, micro-EDXRF and X-ray digital radiography for the study of material composition and technology of fabrication. The combination of these analytical and examination techniques showed that all artefacts are made of bronze with As, Sb and Pb impurities, and that the nails were most likely manufactured using the casting-on technique. These results reinforce the use of binary bronze by Late Bronze Age in the region, and the incorporation of new fabrication technologies that resulted from ancient spheres of interaction. - Highlights: → EDXRF, micro-EDXRF and X-ray digital radiography in cultural heritage studies. → Archaeometallurgical study of a Late Bronze Age artefact collection from Portugal. → Practise of a specific and traditional bronze metallurgy. → Appearance of technological innovations as the casting-on technique.

  18. Optimizing image quality and dose for digital radiography of distal pediatric extremities using the contrast-to-noise ratio

    International Nuclear Information System (INIS)

    Hess, R.; Neitzel, U.

    2012-01-01

    Purpose: To investigate the influence of X-ray tube voltage and filtration on image quality in terms of contrast-to-noise ratio (CNR) and dose for digital radiography of distal pediatric extremities and to determine conditions that give the best balance of CNR and patient dose. Materials and Methods: In a phantom study simulating the absorption properties of distal extremities, the CNR and the related patient dose were determined as a function of tube voltage in the range 40 - 66 kV, both with and without additional filtration of 0.1 mm Cu/1 mm Al. The measured CNR was used as an indicator of image quality, while the mean absorbed dose (MAD) - determined by a combination of measurement and simulation - was used as an indicator of the patient dose. Results: The most favorable relation of CNR and dose was found for the lowest tube voltage investigated (40 kV) without additional filtration. Compared to a situation with 50 kV or 60 kV, the mean absorbed dose could be lowered by 24 % and 50 %, respectively, while keeping the image quality (CNR) at the same level. Conclusion: For digital radiography of distal pediatric extremities, further CNR and dose optimization appears to be possible using lower tube voltages. Further clinical investigation of the suggested parameters is necessary. (orig.)

  19. Advantages obtained in radiation protection when using computerized radiography tests - CR (digital) in processing plants

    International Nuclear Information System (INIS)

    Jose, Joao Carlos Videira; Milani, Hilton Sergio B.; Paes, Eliseu Almir de Oliveira; Boita, Mario de; Souza, Laercio de; Serra, Flavio Augusto dos Santos

    2002-01-01

    During the year 2000, the ARCtest initiated the development of the research for adapting the Computerized Radiography - CR, originally conceived for medical applications, for the Industry, trying initially to attend the requirements of the processing plants, concerning to the detection of deterioration mechanisms (evaluation of the piping integrity). Due to the obtained excellent results, the possibility of utilization the Computerized Radiography - CR in the radiographic inspection were studied during the shutdown of the Catalytic Cracking Unit of the PETROBRAS-REPLAN, specifically in the replacement of the CO boiler superheater, where a large number of the small diameter welded joints have been predicted

  20. Peri-implant assessment via cone beam computed tomography and digital periapical radiography: an ex vivo study

    Directory of Open Access Journals (Sweden)

    Nicolau Silveira-Neto

    Full Text Available OBJECTIVES: This research evaluated detail registration in peri-implant bone using two different cone beam computer tomography systems and a digital periapical radiograph. METHODS: Three different image acquisition protocols were established for each cone beam computer tomography apparatus, and three clinical situations were simulated in an ex vivo fresh pig mandible: buccal bone defect, peri-implant bone defect, and bone contact. Data were subjected to two analyses: quantitative and qualitative. The quantitative analyses involved a comparison of real specimen measures using a digital caliper in three regions of the preserved buccal bone – A, B and E (control group – to cone beam computer tomography images obtained with different protocols (kp1, kp2, kp3, ip1, ip2, and ip3. In the qualitative analyses, the ability to register peri-implant details via tomography and digital periapical radiography was verified, as indicated by twelve evaluators. Data were analyzed with ANOVA and Tukey’s test (α=0.05. RESULTS: The quantitative assessment showed means statistically equal to those of the control group under the following conditions: buccal bone defect B and E with kp1 and ip1, peri-implant bone defect E with kp2 and kp3, and bone contact A with kp1, kp2, kp3, and ip2. Qualitatively, only bone contacts were significantly different among the assessments, and the p3 results differed from the p1 and p2 results. The other results were statistically equivalent. CONCLUSIONS: The registration of peri-implant details was influenced by the image acquisition protocol, although metal artifacts were produced in all situations. The evaluators preferred the Kodak 9000 3D cone beam computer tomography in most cases. The evaluators identified buccal bone defects better with cone beam computer tomography and identified peri-implant bone defects better with digital periapical radiography.

  1. Modeling indirect detectors for performance optimization of a digital mammographic detector for dual energy applications

    International Nuclear Information System (INIS)

    Martini, N; Koukou, V; Sotiropoulou, P; Nikiforidis, G; Kalyvas, N; Michail, C; Valais, I; Kandarakis, I; Fountos, G; Bakas, A

    2015-01-01

    Dual Energy imaging is a promising method for visualizing masses and microcalcifications in digital mammography. The advent of two X-ray energies (low and high) requires a suitable detector. The scope of this work is to determine optimum detector parameters for dual energy applications. The detector was modeled through the linear cascaded (LCS) theory. It was assumed that a phosphor material was coupled to a CMOS photodetector (indirect detection). The pixel size was 22.5 μm. The phosphor thickness was allowed to vary between 20mg/cm 2 and 160mg/cm 2 The phosphor materials examined where Gd 2 O 2 S:Tb and Gd 2 O 2 S:Eu. Two Tungsten (W) anode X-ray spectra at 35 kV (filtered with 100 μm Palladium (Pd)) and 70 kV (filtered with 800 pm Ytterbium (Yb)), corresponding to low and high energy respectively, were considered to be incident on the detector. For each combination the contrast- to-noise ratio (CNR) and the detector optical gain (DOG), showing the sensitivity of the detector, were calculated. The 40 mg/cm 2 and 70 mg/cm 2 Gd 2 O 2 S:Tb exhibited the higher DOG values for the low and high energy correspondingly. Higher CNR between microcalcification and mammary gland exhibited the 70mg/cm 2 and the 100mg/cm 2 Gd 2 O 2 S:Tb for the low and the high energy correspondingly

  2. Management of pediatric radiation dose using GE's Revolution digital radiography systems

    International Nuclear Information System (INIS)

    Jabri, K.N.; Uppaluri, R.; Xue Ping

    2004-01-01

    Digital flat-panel X-ray detectors offer excellent image quality and dose efficiency in addition to clinical productivity, connectivity, and adaptability to advanced clinical applications. GE's Revolution systems provide two modes of exposure control for setting the dose operating point, fixed time and automatic exposure control, the latter of which maintains high image signal-to-noise ratio for the given technique settings. In addition to enhancing detail contrast and compressing the dynamic range, postprocessing automatically determines the best window level and width for display, taking into account the dose at which the image was acquired. Several studies have examined the reduction in patient dose achievable with Revolution systems as compared to competing technologies, and results indicate significant dose savings with equivalent or superior image quality. For pediatric exams, pediatric default techniques provide for a lower patient dose as compared to adult techniques. Therefore, GE's Revolution systems can achieve a high image quality-to-dose ratio for pediatric imaging using the combined advantages of dose-efficient detection, advanced postprocessing, and independently adjustable pediatric techniques. (orig.)

  3. Digital radiography: optimization of image quality and dose using multi-frequency software.

    Science.gov (United States)

    Precht, H; Gerke, O; Rosendahl, K; Tingberg, A; Waaler, D

    2012-09-01

    New developments in processing of digital radiographs (DR), including multi-frequency processing (MFP), allow optimization of image quality and radiation dose. This is particularly promising in children as they are believed to be more sensitive to ionizing radiation than adults. To examine whether the use of MFP software reduces the radiation dose without compromising quality at DR of the femur in 5-year-old-equivalent anthropomorphic and technical phantoms. A total of 110 images of an anthropomorphic phantom were imaged on a DR system (Canon DR with CXDI-50 C detector and MLT[S] software) and analyzed by three pediatric radiologists using Visual Grading Analysis. In addition, 3,500 images taken of a technical contrast-detail phantom (CDRAD 2.0) provide an objective image-quality assessment. Optimal image-quality was maintained at a dose reduction of 61% with MLT(S) optimized images. Even for images of diagnostic quality, MLT(S) provided a dose reduction of 88% as compared to the reference image. Software impact on image quality was found significant for dose (mAs), dynamic range dark region and frequency band. By optimizing image processing parameters, a significant dose reduction is possible without significant loss of image quality.

  4. Gain and offset calibration reduces variation in exposure-dependent SNR among systems with identical digital flat-panel detectors.

    Science.gov (United States)

    Willis, Charles E; Vinogradskiy, Yevgeniy Y; Lofton, Brad K; White, R Allen

    2011-07-01

    The conditions under which vendor performance criteria for digital radiography systems are obtained do not adequately simulate the conditions of actual clinical imaging with respect to radiographic technique factors, scatter production, and scatter control. Therefore, the relationship between performance under ideal conditions and performance in clinical practice remains unclear. Using data from a large complement of systems in clinical use, the authors sought to develop a method to establish expected performance criteria for digital flat-panel radiography systems with respect to signal-to-noise ratio (SNR) versus detector exposure under clinical conditions for thoracic imaging. The authors made radiographic exposures of a patient-equivalent chest phantom at 125 kVp and 180 cm source-to-image distance. The mAs value was modified to produce exposures above and below the mAs delivered by automatic exposure control. Exposures measured free-in-air were corrected to the imaging plane by the inverse square law, by the attenuation factor of the phantom, and by the Bucky factor of the grid for the phantom, geometry, and kilovolt peak. SNR was evaluated as the ratio of the mean to the standard deviation (SD) of a region of interest automatically selected in the center of each unprocessed image. Data were acquired from 18 systems, 14 of which were tested both before and after gain and offset calibration. SNR as a function of detector exposure was interpolated using a double logarithmic function to stratify the data into groups of 0.2, 0.5, 1.0, 2.0, and 5.0 mR exposure (1.8, 4.5, 9.0, 18, and 45 microGy air KERMA) to the detector. The mean SNR at each exposure interval after calibration exhibited linear dependence on the mean SNR before calibration (r2=0.9999). The dependence was greater than unity (m = 1.101 +/- 0.006), and the difference from unity was statistically significant (p grid replacement. The nonconformant behavior of the other system was corrected by replacing

  5. [Digital thoracic radiology: devices, image processing, limits].

    Science.gov (United States)

    Frija, J; de Géry, S; Lallouet, F; Guermazi, A; Zagdanski, A M; De Kerviler, E

    2001-09-01

    In a first part, the different techniques of digital thoracic radiography are described. Since computed radiography with phosphore plates are the most commercialized it is more emphasized. But the other detectors are also described, as the drum coated with selenium and the direct digital radiography with selenium detectors. The other detectors are also studied in particular indirect flat panels detectors and the system with four high resolution CCD cameras. In a second step the most important image processing are discussed: the gradation curves, the unsharp mask processing, the system MUSICA, the dynamic range compression or reduction, the soustraction with dual energy. In the last part the advantages and the drawbacks of computed thoracic radiography are emphasized. The most important are the almost constant good quality of the pictures and the possibilities of image processing.

  6. Applications and characteristics of imaging plates as detector in neutron radiography at SINQ

    CERN Document Server

    Kolbe, H; Gunia, W; Körner, S

    1999-01-01

    Imaging plate technique is a commonly accepted method in many fields as in medicine, biology and physics for detection of the distribution of beta- and gamma-radiation or X-rays on large areas. Recently a new type of imaging plate sensitive to neutrons has been developed. The storage layer is doped with gadolinium, which, after absorption of neutrons, produces radiation detectable by the same sensitive crystals used in conventional imaging plates. At the spallation neutron source, SINQ, at the Paul Scherrer Institut (CH) some of the characteristics of the neutron radiography station in combination with the imaging plate technique were investigated. The intensity distribution of the source was measured to check the accuracy for quantification of the image data. Also, the reproducibility of results obtained by this detection system was stated. For a test object, the high selectivity for different neutron absorption is demonstrated at details with low contrast. The obtainable spatial resolution was determined re...

  7. Improvement of single detector proton radiography by incorporating intensity of time-resolved dose rate functions

    Science.gov (United States)

    Zhang, Rongxiao; Jee, Kyung-Wook; Cascio, Ethan; Sharp, Gregory C.; Flanz, Jacob B.; Lu, Hsiao-Ming

    2018-01-01

    Proton radiography, which images patients with the same type of particles as those with which they are to be treated, is a promising approach to image guidance and water equivalent path length (WEPL) verification in proton radiation therapy. We have shown recently that proton radiographs could be obtained by measuring time-resolved dose rate functions (DRFs) using an x-ray amorphous silicon flat panel. The WEPL values were derived solely from the root-mean-square (RMS) of DRFs, while the intensity information in the DRFs was filtered out. In this work, we explored the use of such intensity information for potential improvement in WEPL accuracy and imaging quality. Three WEPL derivation methods based on, respectively, the RMS only, the intensity only, and the intensity-weighted RMS were tested and compared in terms of the quality of obtained radiograph images and the accuracy of WEPL values. A Gammex CT calibration phantom containing inserts made of various tissue substitute materials with independently measured relative stopping powers (RSP) was used to assess the imaging performances. Improved image quality with enhanced interfaces was achieved while preserving the accuracy by using intensity information in the calibration. Other objects, including an anthropomorphic head phantom, a proton therapy range compensator, a frozen lamb’s head and an ‘image quality phantom’ were also imaged. Both the RMS only and the intensity-weighted RMS methods derived RSPs within  ±  1% for most of the Gammex phantom inserts, with a mean absolute percentage error of 0.66% for all inserts. In the case of the insert with a titanium rod, the method based on RMS completely failed, whereas that based on the intensity-weighted RMS was qualitatively valid. The use of intensity greatly enhanced the interfaces between different materials in the obtained WEPL images, suggesting the potential for image guidance in areas such as patient positioning and tumor tracking by proton

  8. Design and image-quality performance of high resolution CMOS-based X-ray imaging detectors for digital mammography

    Science.gov (United States)

    Cha, B. K.; Kim, J. Y.; Kim, Y. J.; Yun, S.; Cho, G.; Kim, H. K.; Seo, C.-W.; Jeon, S.; Huh, Y.

    2012-04-01

    In digital X-ray imaging systems, X-ray imaging detectors based on scintillating screens with electronic devices such as charge-coupled devices (CCDs), thin-film transistors (TFT), complementary metal oxide semiconductor (CMOS) flat panel imagers have been introduced for general radiography, dental, mammography and non-destructive testing (NDT) applications. Recently, a large-area CMOS active-pixel sensor (APS) in combination with scintillation films has been widely used in a variety of digital X-ray imaging applications. We employed a scintillator-based CMOS APS image sensor for high-resolution mammography. In this work, both powder-type Gd2O2S:Tb and a columnar structured CsI:Tl scintillation screens with various thicknesses were fabricated and used as materials to convert X-ray into visible light. These scintillating screens were directly coupled to a CMOS flat panel imager with a 25 × 50 mm2 active area and a 48 μm pixel pitch for high spatial resolution acquisition. We used a W/Al mammographic X-ray source with a 30 kVp energy condition. The imaging characterization of the X-ray detector was measured and analyzed in terms of linearity in incident X-ray dose, modulation transfer function (MTF), noise-power spectrum (NPS) and detective quantum efficiency (DQE).

  9. Quality comparison between DEF-10 digital image from simulation technique and Computed Tomography (CR) technique in industrial radiography

    International Nuclear Information System (INIS)

    Siti Nur Syatirah Ismail

    2012-01-01

    The study was conducted to make comparison of digital image quality of DEF-10 from the techniques of simulation and computed radiography (CR). The sample used is steel DEF-10 with thickness of 15.28 mm. In this study, the sample is exposed to radiation from X-ray machine (ISOVOLT Titan E) with certain parameters. The parameters used in this study such as current, volt, exposure time and distance are specified. The current and distance of 3 mA and 700 mm respectively are specified while the applied voltage varies at 140, 160, 180 and 200 kV. The exposure time is reduced at a rate of 0, 20, 40, 60 and 80 % for each sample exposure. Digital image of simulation produced from aRTist software whereas digital image of computed radiography produced from imaging plate. Therefore, both images were compared qualitatively (sensitivity) and quantitatively (Signal to-Noise Ratio; SNR, Basic Spatial Resolution; SRb and LOP size) using Isee software. Radiographic sensitivity is indicated by Image Quality Indicator (IQI) which is the ability of the CR system and aRTist software to identify IQI of wire type when the time exposure is reduced up to 80% according to exposure chart ( D7; ISOVOLT Titan E). The image of the thinnest wire diameter achieved by radiograph from simulation and CR are the wire numbered 7 rather than the wire numbered 8 required by the standard. In quantitative comparison, this study shows that the SNR values decreases with reducing exposure time. SRb values increases for simulation and decreases for CR when the exposure time decreases and the good image quality can be achieved at 80% reduced exposure time. The high SNR and SRb values produced good image quality in CR and simulation techniques respectively. (author)

  10. Accuracy of Digital Radiography and Cone Beam Computed Tomography on Periapical Radiolucency Detection in Endodontically Treated Teeth

    Directory of Open Access Journals (Sweden)

    Tadas Venskutonis

    2014-07-01

    Full Text Available Objectives: The aim of the present study was to compare the accuracy of intraoral digital periapical radiography and cone beam computed tomography in the detection of periapical radiolucencies in endodontically treated teeth. Material and Methods: Radiographic images (cone beam computed tomography [CBCT] scans and digital periapical radiography [PR] images from 60 patients, achieved from September 2008 to July 2013, were retrieved from databases of the Department of Oral Diseases, Lithuanian University of Health Sciences. Twenty patients met inclusion criteria and were selected for further evaluation. Results: In 20 patients (42.4 [SD 12.1] years, 65% men and 35% women a total of 35 endodontically treated teeth (1.75 [SD 0.91]; 27 in maxilla and 8 in mandible were evaluated. Overall, it was observed a statistical significant difference between the number of periapical lesions observed in the CBCT (n = 42 and radiographic (n = 24 examinations (P < 0.05. In molar teeth, CBCT identify a significantly higher amount of periapical lesions than with the radiographic method (P < 0.05. There were significant differences between CBCT and PR in the mean number of lesions identified per tooth (1.2 vs 0.66, P = 0.03, number of teeth with lesions (0.71 vs 0.46, P = 0.03 and number of lesions identified per canal (0.57 vs 0.33, P = 0.005. Considering CBCT as “gold standard” in lesion detection with the sensitivity, specificity and accuracy considering as score 1, then the same parameters of PR were 0.57, 1 and 0.76 respectively. Conclusions: Within the limitations of the present study, it can be concluded that cone beam computed tomography scans were more accurate compared to digital periapical radiographs for detecting periapical radiolucencies in endodontically treated teeth. The difference was more pronounced in molar teeth.

  11. Optimized digital filtering techniques for radiation detection with HPGe detectors

    Energy Technology Data Exchange (ETDEWEB)

    Salathe, Marco, E-mail: marco.salathe@mpi-hd.mpg.de; Kihm, Thomas, E-mail: mizzi@mpi-hd.mpg.de

    2016-02-01

    This paper describes state-of-the-art digital filtering techniques that are part of GEANA, an automatic data analysis software used for the GERDA experiment. The discussed filters include a novel, nonlinear correction method for ballistic deficits, which is combined with one of three shaping filters: a pseudo-Gaussian, a modified trapezoidal, or a modified cusp filter. The performance of the filters is demonstrated with a 762 g Broad Energy Germanium (BEGe) detector, produced by Canberra, that measures γ-ray lines from radioactive sources in an energy range between 59.5 and 2614.5 keV. At 1332.5 keV, together with the ballistic deficit correction method, all filters produce a comparable energy resolution of ~1.61 keV FWHM. This value is superior to those measured by the manufacturer and those found in publications with detectors of a similar design and mass. At 59.5 keV, the modified cusp filter without a ballistic deficit correction produced the best result, with an energy resolution of 0.46 keV. It is observed that the loss in resolution by using a constant shaping time over the entire energy range is small when using the ballistic deficit correction method.

  12. Standard practice for radiological examination using digital detector arrays

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice establishes the minimum requirements for radiological examination for metallic and nonmetallic material using a digital detector array (DDA) system. 1.2 The requirements in this practice are intended to control the quality of radiologic images and are not intended to establish acceptance criteria for parts or materials. 1.3 This practice covers the radiologic examination with DDAs including DDAs described in Practice E2597 such as a device that contains a photoconductor attached to a Thin Film Transistor (TFT) read out structure, a device that has a phosphor coupled directly to an amorphous silicon read-out structure, and devices where a phosphor is coupled to a CMOS (Complementary metal–oxide–semiconductor) array, a Linear Detector Array (LDA) or a CCD (charge coupled device) crystalline silicon read-out structure. 1.4 The DDA shall be selected for an NDT application based on knowledge of the technology described in Guide , and of the selected DDA properties provided by the manufactu...

  13. Proton radiography using highpower femtosecond laser

    International Nuclear Information System (INIS)

    Choi, Chang Il

    2010-08-01

    A femtosecond laser emits pulses whose width is between few and few hundreds femtoseconds (10 -15 s). The production mechanism of the high energy protons generated by the femtosecond laser is not clear so far, but the technologies have been improving. The applications using the generated protons are the proton therapy, proton radiography, nuclear physics, security inspection, and so on. Especially in the radiography, the laser-generated protons are very useful to obtain high quality images of thin objects, because protons are able to penetrate an object following an almost straight path and give a depth distribution information of various elements in a subject. Since the laser-driven protons require lower cost and smaller facility than accelerator-based protons, the radiography using laser-driven protons have been of interest. In this research, we have performed the radiography experiments by using protons generated by the 100 TW titanium sapphire femtosecond laser facility of Advanced Photonics Research Institute (APRI) of Gwangju Institute of Science Technology (GIST). A CR-39 Solid State Nuclear Track Detector (SSNTD) has been used as radiography screen. The radiography digital images have been obtained by using an optical microscope and a CCD camera. Modulation Transfer Function (MTF) has been derived from analyzing the obtained images, and the spatial resolution of the images have been evaluated. And, we have performed the radiography experiments of monoenergetic proton from the Tandem Van de Graaff accelerator of Korea Institute of Geoscience and Mineral Resources (KIGAM). We have obtained and compared the radiography images from other proton production methods which are the laser and the accelerator, respectively. And also, we have found out the optimized chemical etching condition, in order to improve the spatial resolution of the radiography images. Finally, the evaluated maximum spatial resolution of the images are 2.09 μm

  14. A new digital pulse generator for the CALIFA detector

    Energy Technology Data Exchange (ETDEWEB)

    Bendel, Michael; Gernhaeuser, Roman; Heiss, Benjamin; Klenze, Philipp; Remmels, Patrick; Winkel, Max [Physik Department E12, Technische Universitaet Muenchen (Germany); Collaboration: R3B-Collaboration

    2015-07-01

    The 4π-calorimeter CALIFA ist one of the major detectors of the R3B-experiment at the upcoming Facility for Antiproton and Ion Research in Darmstadt. The monitoring of stability, single channel properties, temperature effects and rate dependency in a high resolution, high granularity calorimeter is essential for the success of the whole experiment. A new digital pulse generator will emulate the complex signal of the CsI(Tl) crystals in order to fine tune the online pulse shape analysis for particle identification, background suppression, energy calibration and for deadtime and pileup studies. The total pulse generator firmware is implemented into the digital readout platform FEBEX used in CALIFA. The FPGA and a small analog add on board allow for highly flexible parameter adjustment. New applications are easy to implement and even very complex shapes are produced by simple lookup tables. The concept, features and implementation of a prototype and a first application in the CALIFA Demonstrator Experiment in October 2014 at GSI in Darmstadt are presented.

  15. Diagnostic Accuracy of Digital and Conventional Radiography in the Detection of Non-Cavitated Approximal Dental Caries

    International Nuclear Information System (INIS)

    Abesi, F.; Mirshekar, A.; Moudi, E.; Seyedmajidi, M.; Haghanifar, S.; Haghighat, N.; Bijani, A.

    2012-01-01

    Radiography plays an important role in the detection of interproximal caries. The aim of the present study was to determine diagnostic accuracy of charge coupled devices, Photo Stimulable Phosphor and film radiography in detecting non-cavitated caries. Seventy-two non-cavitated approximal surfaces of extracted human posterior teeth were radiographed under standardized conditions using three intraoral modalities: charge coupled devices Dixi3 (Planmeca, Finland), PSP Digora PCT (Soredex, Finland), and E-speed film (Kodak, USA). Radiographs were interpreted by four observers and caries lesions were classified as sound (R0), restricted to enamel (R1), reaching the dentinoenamel junction and the outer half of the dentin (R2) and the inner half of the dentin (R3). The teeth were subsequently sectioned for histological analysis which served as the gold standard for radiographic examination. Microscopic examinations showed that the distribution of caries were 63.9% sound, 18.1% enamel, 9.7% dentinoenamel junction and outer half of the dentin and 8.3% into the inner half of the dentin. The sensitivity and specificity of film, charge coupled devices and Photo Stimulable Phosphor for the detection of enamel caries were 38% and 98%; 15% and 96%; and 23% and 98%, respectively. The sensitivity and specificity of film, charge coupled devices and Photo Stimulable Phosphor for the detection of both dentin and enamel caries were 55% and 100%; 45% and 100% ; and 55% and 100%, respectively. The results demonstrated that the diagnostic accuracy of digital images is similar to that of conventional film radiography in the detection of non-cavitated approximal caries.

  16. Development of a mini-mobile digital radiography system by using wireless smart devices.

    Science.gov (United States)

    Jeong, Chang-Won; Joo, Su-Chong; Ryu, Jong-Hyun; Lee, Jinseok; Kim, Kyong-Woo; Yoon, Kwon-Ha

    2014-08-01

    The current technologies that trend in digital radiology (DR) are toward systems using portable smart mobile as patient-centered care. We aimed to develop a mini-mobile DR system by using smart devices for wireless connection into medical information systems. We developed a mini-mobile DR system consisting of an X-ray source and a Complementary Metal-Oxide Semiconductor (CMOS) sensor based on a flat panel detector for small-field diagnostics in patients. It is used instead of the systems that are difficult to perform with a fixed traditional device. We also designed a method for embedded systems in the development of portable DR systems. The external interface used the fast and stable IEEE 802.11n wireless protocol, and we adapted the device for connections with Picture Archiving and Communication System (PACS) and smart devices. The smart device could display images on an external monitor other than the monitor in the DR system. The communication modules, main control board, and external interface supporting smart devices were implemented. Further, a smart viewer based on the external interface was developed to display image files on various smart devices. In addition, the advantage of operators is to reduce radiation dose when using remote smart devices. It is integrated with smart devices that can provide X-ray imaging services anywhere. With this technology, it can permit image observation on a smart device from a remote location by connecting to the external interface. We evaluated the response time of the mini-mobile DR system to compare to mobile PACS. The experimental results show that our system outperforms conventional mobile PACS in this regard.

  17. Comparative study between computed radiography and conventional radiography

    International Nuclear Information System (INIS)

    Noorhazleena Azaman; Khairul Anuar Mohd Salleh; Sapizah Rahim; Shaharudin Sayuti; Arshad Yassin; Abdul Razak Hamzah

    2010-01-01

    In Industrial Radiography, there are many criteria that need to be considered based on established standards to accept or reject the radiographic film. For conventional radiography, we need to consider the optical density by using the densitometer when viewing the film on the viewer. But in the computed radiography (CR) we need to evaluate and performed the analysis from the quality of the digital image through grey value. There are many factors that affected the digital image quality. One of the factors which are affected to the digital image quality in the image processing is grey value that related to the contrast resolution. In this work, we performed grey value study measurement on digital radiography systems and compared it with exposed films in conventional radiography. The test sample is a steel step wedge. We found out the contrast resolution is higher in Computed Radiography compared with Conventional Radiography. (author)

  18. Exposure reduction in general dental practice using digital x-ray imaging system for intraoral radiography with additional x-ray beam filter

    International Nuclear Information System (INIS)

    Shibuya, Hitoshi; Mori, Toshimichi; Hayakawa, Yoshihiko; Kuroyanagi, Kinya; Ota, Yoshiko

    1997-01-01

    To measure exposure reduction in general dental practice using digital x-ray imaging systems for intraoral radiography with additional x-ray beam filter. Two digital x-ray imaging systems, Pana Digital (Pana-Heraus Dental) and CDR (Schick Technologies), were applied for intraoral radiography in general dental practice. Due to the high sensitivity to x-rays, additional x-ray beam filters for output reduction were used for examination. An Orex W II (Osada Electric Industry) x-ray generator was operated at 60 kVp, 7 mA. X-ray output (air-kerma; Gy) necessary for obtaining clinically acceptable images was measured at 0 to 20 cm in 5 cm steps from the cone tip using an ionizing chamber type 660 (Nuclear Associates) and compared with those for Ektaspeed Plus film (Eastman Kodak). The Pana Digital system was used with the optional filter supplied by Pana-Heraus Dental which reduced the output to 38%. The exposure necessary to obtain clinically acceptable images was only 40% of that for the film. The CDR system was used with the Dental X-ray Beam Filter Kit (Eastman Kodak) which reduced the x-ray output to 30%. The exposure necessary to obtain clinically acceptable images was only 20% of that for the film. The two digital x-ray imaging systems, Pana Digital and CDR, provided large dose savings (60-80%) compared with Ektaspeed Plus film when applied for intraoral radiography in general dental practice. (author)

  19. A digital divider with extension bits for position-sensitive detectors

    International Nuclear Information System (INIS)

    Koike, Masaki; Hasegawa, Ken-ichi

    1988-01-01

    Digitizing errors produced in a digital divider for position-sensitive detectors have been reduced by adding extension bits to data bits. A relation between the extension bits and the data bits to obtain perfect position uniformity is also given. A digital divider employing 10 bit ADCs and 6 bit extension circuits has been constructed. (orig.)

  20. Skin entrance dose with and without lead apron in digital panoramic radiography for selected sensitive body regions.

    Science.gov (United States)

    Schulze, Ralf Kurt Willy; Cremers, Catrin; Karle, Heiko; de Las Heras Gala, Hugo

    2017-05-01

    The aim of this study was to compare the dose at skin level at five significant anatomical regions for panoramic radiography devices with and without lead apron by means of a highly sensitive dosimeter. A female RANDO-phantom was exposed in five different digital panoramic radiography systems, and the dose at skin level was assessed tenfold for each measurement region by means of a highly sensitive solid-state-dosimeter. The five measurement regions selected were the thyroid, both female breasts, the gonads, and a central region in the back of the phantom. For each panoramic machine, the measurements were performed in two modes: with and without a commercial lead apron specifically designed for panoramic radiography. Reproducibility of the measurements was expressed by absolute differences and the coefficient of variation. Values between shielded and unshielded doses were pooled for each region and compared by means of the paired Wilcoxon tests (p ≤ 0.05). Reproducibility as represented by the mean CV was 22 ± 52 % (median 2.3 %) with larger variations for small dose values. Doses at skin level ranged between 0.00 μGy at the gonads and 85.39 μGy at the unshielded thyroid (mean ± SD 15 ± 24 μGy). Except for the gonads, the dose in all the other regions was significantly lower (p < 0.001) when a lead apron was applied. Unshielded doses were between 1.02-fold (thyroid) and 112-fold (at the right breast) higher than those with lead apron shielding (mean: 14-fold ± 18-fold). Although the doses were entirely very low, we observed a significant increase in dose in the radiation-sensitive female breast region when no lead apron was used. Future discussions on shielding requirements for panoramic radiography should focus on these differences in the light of the linear non-threshold (LNT) theory which is generally adopted in medical imaging.

  1. Radiographic inspection. Film replacement with digital detector arrays in aerospace applications

    International Nuclear Information System (INIS)

    Schulte, Frank; Bavendiek, Klaus

    2016-01-01

    The new Digital Radiographic Inspection method replace more and more the conventional Film technique. For DDA (Digital Detector Array) systems it is currently necessary to use automated or semi-automated systems. For CR (Computer Radiography) Systems the conventional Film Systems may be used. For this CR technique operators can use same X-Ray Units (Bunker) and same X-Ray equipment. But on CR technique we have basically the same settings like the Film-based technique. More or less same exposure times and for aerospace application long scanning times for the CR foils. In fact there is no big benefit in capacity or in economical view. Regarding this issue we thought about the option to use a DDA System instead of a Film or CR System to use the current Film Equipment (Bunker, Generator, Tube.) and replace this 1:1 by a manual system. In this time only small detectors with fine pixel pitch was available on the market. With this type of DDA's is was absolutely uneconomical to inspect parts in serial inspection. Therefore a new generation of DDA's were developed, which is able to replace Film or CR System 1:1 with adequate economical properties for specific applications. The new PerkinElmer XRD 1611 Panel has a size of 40 x 40 cm and a pixel pitch of 100 μm. The baseline for the new DDA Panel was the most used X-Ray Film in size 30 x 40 cm. The Pixel Pitch and requirements for Bad Pixel based on the requirements for spatial resolution of the applicable ASTM standards and different customer specifications for castings. With this new DDA System is it possible to inspect small and medium castings in very short time with excellent image quality. The System is able to process images under 1 minute include averaging. Images will be transferred by a specific software tool to an offline reading station where certified Level 2 operator can inspect the images. Images will be archived as 16bit DICONDE File. All relevant images information are included in DICONDE File

  2. TH-C-BRD-05: Reducing Proton Beam Range Uncertainty with Patient-Specific CT HU to RSP Calibrations Based On Single-Detector Proton Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Doolan, P [University College London, London (United Kingdom); Massachusetts General Hospital, Boston, MA (United States); Sharp, G; Testa, M; Lu, H-M [Massachusetts General Hospital, Boston, MA (United States); Bentefour, E [Ion Beam Applications (IBA), Louvain la Neuve (Belgium); Royle, G [University College London, London (United Kingdom)

    2014-06-15

    Purpose: Beam range uncertainty in proton treatment comes primarily from converting the patient's X-ray CT (xCT) dataset to relative stopping power (RSP). Current practices use a single curve for this conversion, produced by a stoichiometric calibration based on tissue composition data for average, healthy, adult humans, but not for the individual in question. Proton radiographs produce water-equivalent path length (WEPL) maps, dependent on the RSP of tissues within the specific patient. This work investigates the use of such WEPL maps to optimize patient-specific calibration curves for reducing beam range uncertainty. Methods: The optimization procedure works on the principle of minimizing the difference between the known WEPL map, obtained from a proton radiograph, and a digitally-reconstructed WEPL map (DRWM) through an RSP dataset, by altering the calibration curve that is used to convert the xCT into an RSP dataset. DRWMs were produced with Plastimatch, an in-house developed software, and an optimization procedure was implemented in Matlab. Tests were made on a range of systems including simulated datasets with computed WEPL maps and phantoms (anthropomorphic and real biological tissue) with WEPL maps measured by single detector proton radiography. Results: For the simulated datasets, the optimizer showed excellent results. It was able to either completely eradicate or significantly reduce the root-mean-square-error (RMSE) in the WEPL for the homogeneous phantoms (to zero for individual materials or from 1.5% to 0.2% for the simultaneous optimization of multiple materials). For the heterogeneous phantom the RMSE was reduced from 1.9% to 0.3%. Conclusion: An optimization procedure has been designed to produce patient-specific calibration curves. Test results on a range of systems with different complexities and sizes have been promising for accurate beam range control in patients. This project was funded equally by the Engineering and Physical Sciences

  3. Study on Construction of a Medical X-Ray Direct Digital Radiography System and Hybrid Preprocessing Methods

    Directory of Open Access Journals (Sweden)

    Yong Ren

    2014-01-01

    Full Text Available We construct a medical X-ray direct digital radiography (DDR system based on a CCD (charge-coupled devices camera. For the original images captured from X-ray exposure, computer first executes image flat-field correction and image gamma correction, and then carries out image contrast enhancement. A hybrid image contrast enhancement algorithm which is based on sharp frequency localization-contourlet transform (SFL-CT and contrast limited adaptive histogram equalization (CLAHE, is proposed and verified by the clinical DDR images. Experimental results show that, for the medical X-ray DDR images, the proposed comprehensive preprocessing algorithm can not only greatly enhance the contrast and detail information, but also improve the resolution capability of DDR system.

  4. An efficient and cost-effective microchannel plate detector for slow neutron radiography

    Science.gov (United States)

    Wiggins, B. B.; Vadas, J.; Bancroft, D.; deSouza, Z. O.; Huston, J.; Hudan, S.; Baxter, D. V.; deSouza, R. T.

    2018-05-01

    A novel approach for efficiently imaging objects with slow neutrons in two dimensions is realized. Neutron sensitivity is achieved by use of a boron doped microchannel plate (MCP). The resulting electron avalanche is further amplified with a Z-stack MCP before being sensed by two orthogonally oriented wire planes. Coupling of the wire planes to delay lines efficiently encodes the position information as a time difference. To determine the position resolution, slow neutrons were used to illuminate a Cd-mask placed directly in front of the detector. Peaks in the resulting spectrum exhibited an average peak width of 329 μm FWHM, corresponding to an average intrinsic resolution of 216 μm. The center region of the detector exhibits a significantly better spatial resolution with an intrinsic resolution of <100 μm observed.

  5. Dual-energy radiography of bone tissues using ZnSe-based scintielectronic detectors

    International Nuclear Information System (INIS)

    Grinyov, B.; Ryzhikov, V.; Lecoq, P.; Naydenov, S.; Opolonin, A.; Lisetskaya, E.; Galkin, S.; Shumeiko, N.

    2007-01-01

    Detectors of the scintillator-photodiode type were obtained on the basis of CsI(Tl), CdWO 4 and ZnSe(Te) crystals, and their comparative study was carried out, aiming at their use in X-ray computer tomography (CT). Because of their low afterglow level (10 ppm after 10 ms), CWO and ZnSe crystals are preferable for this application. A drawback of CWO is its lower (by 3 times) light output as compared with CsI(Tl). ZnSe has low transparence to intrinsic radiation; however, up to energies of 60-70 keV it is superior, as for the whole complex of its parameter, to materials traditionally used for CT detectors. The use of a dual-energy receiving-detecting circuit with a detector pair ZnSe/CsI or ZnSe/CdWO allows efficient distinction between muscular and bone tissues, which supports our earlier theoretical assumptions that this method could be successfully used for separate detection of materials differing in their effective atomic number Z eff and local density (e.g., calcium contents in bone densitometry)

  6. New standards for digital radiography and qualification of detectors; Neue Standards zur Digitalen Radiographie und Qualifizierung von Detektoren

    Energy Technology Data Exchange (ETDEWEB)

    Ewert, Uwe; Zscherpel, Uwe [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

    2017-08-01

    The contribution describes the most important standards for radiographic examinations that are revised in different committees. Information is given on new requirements esp. on revised parameters that have to be considered in practical testing procedures and classification. Actually for the revision of ISO 17636-1/2 in 2018 user questions are collected concerning weld seam testing. The DIN 25435 standards for weld seam testing in nuclear technology have been translated into English. Revisions of ASTM standards have to be considered in the actual EN and ISO standards. Since several years the International Institute of Welding (IIW) is also revising the international standards.

  7. The efficacy of the reverse contrast mode in digital radiography for the detection of proximal dentinal caries

    Energy Technology Data Exchange (ETDEWEB)

    Miri, Shimasadat [Dept. of Endodontics, School of Dentistry, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Mehrailzadeh, Sandra; Sadri, Donya [School of Dentistry, Islamic Azad University, Tehran (Iran, Islamic Republic of); Motamedi, Mahmood Reza Kalantar [Dept. of Research, School of Dentistry, Isfahan Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Soltani, Parisa [Dental Students Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of)

    2015-09-15

    This study evaluated the diagnostic accuracy of the reverse contrast mode in intraoral digital radiography for the detection of proximal dentinal caries, in comparison with the original digital radiographs. Eighty extracted premolars with no clinically apparent caries were selected, and digital radiographs of them were taken separately in standard conditions. Four observers examined the original radiographs and the same radiographs in the reverse contrast mode with the goal of identifying proximal dentinal caries. Microscopic sections 5 µm in thickness were prepared from the teeth in the mesiodistal direction. Four slides prepared from each sample used as the diagnostic gold standard. The data were analyzed using SPSS (α=0.05). Our results showed that the original radiographs in order to identify proximal dentinal caries had the following values for sensitivity, specificity, positive predictive value, negative predictive value, and accuracy, respectively: 72.5%, 90%, 87.2%, 76.5%, and 80.9%. For the reverse contrast mode, however, the corresponding values were 63.1%, 89.4%, 87.1%, 73.5%, and 78.8%, respectively. The sensitivity of original digital radiograph for detecting proximal dentinal caries was significantly higher than that of reverse contrast mode (p<0.05). However, no statistically significant differences were found regarding specificity, positive predictive value, negative predictive value, or accuracy (p>0.05). The sensitivity of the original digital radiograph for detecting proximal dentinal caries was significantly higher than that of the reversed contrast images. However, no statistically significant differences were found between these techniques regarding specificity, positive predictive value, negative predictive value, or accuracy.

  8. The efficacy of the reverse contrast mode in digital radiography for the detection of proximal dentinal caries

    International Nuclear Information System (INIS)

    Miri, Shimasadat; Mehrailzadeh, Sandra; Sadri, Donya; Motamedi, Mahmood Reza Kalantar; Soltani, Parisa

    2015-01-01

    This study evaluated the diagnostic accuracy of the reverse contrast mode in intraoral digital radiography for the detection of proximal dentinal caries, in comparison with the original digital radiographs. Eighty extracted premolars with no clinically apparent caries were selected, and digital radiographs of them were taken separately in standard conditions. Four observers examined the original radiographs and the same radiographs in the reverse contrast mode with the goal of identifying proximal dentinal caries. Microscopic sections 5 µm in thickness were prepared from the teeth in the mesiodistal direction. Four slides prepared from each sample used as the diagnostic gold standard. The data were analyzed using SPSS (α=0.05). Our results showed that the original radiographs in order to identify proximal dentinal caries had the following values for sensitivity, specificity, positive predictive value, negative predictive value, and accuracy, respectively: 72.5%, 90%, 87.2%, 76.5%, and 80.9%. For the reverse contrast mode, however, the corresponding values were 63.1%, 89.4%, 87.1%, 73.5%, and 78.8%, respectively. The sensitivity of original digital radiograph for detecting proximal dentinal caries was significantly higher than that of reverse contrast mode (p<0.05). However, no statistically significant differences were found regarding specificity, positive predictive value, negative predictive value, or accuracy (p>0.05). The sensitivity of the original digital radiograph for detecting proximal dentinal caries was significantly higher than that of the reversed contrast images. However, no statistically significant differences were found between these techniques regarding specificity, positive predictive value, negative predictive value, or accuracy

  9. TU-FG-209-08: Distribution of the Deviation Index (DI) in Digital Radiography Practices Across the United States

    Energy Technology Data Exchange (ETDEWEB)

    Jones, A; Shepard, S [UT MD Anderson Cancer Center, Houston, TX (United States); Dave, J [Thomas Jefferson University, Philadelphia, PA (United States); Fisher, R [The Cleveland Clinic, Cleveland, OH (United States); Hulme, K [The Cleveland Clinic, Beachwood, OH (United States); Rill, L [University Florida, Jacksonville Beach, FL (United States); Zamora, D [University of Washington, Seattle, WA (United States); Woodward, A [The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina (United States); Brady, S [St. Jude Children’s Research Hospital, Memphis, TN (United States); MacDougall, R [Children’s Hospital, Boston, MA (United States); Goldman, L [Hartford Hospital, Hartford, CT (United States); Lang, S; Peck, D [Henry Ford Health System, Detroit, MI (United States); Apgar, B [AGFA HealthCare, Greenville, SC (United States); Uzenoff, R [FUJIFILM Medical Systems U.S.A., Inc., Weston, CT (United States); Willis, C [University of Texas MD Anderson Cancer Center, Bellaire, TX (United States)

    2016-06-15

    Purpose: To characterize the distribution of the deviation index (DI) in digital radiography practices across the United States. Methods: DI data was obtained from 10 collaborating institutions in the United States between 2012 and 2015. Each institution complied with the requirements of the Institutional Review Board at their site. DI data from radiographs of the body parts chest, abdomen, pelvis and extremity were analyzed for anteroposterior, posteroanterior, lateral, and decubitus views. The DI data was analyzed both in aggregate and stratified by exposure control method, image receptor technology, patient age, and participating site for each body part and view. The number of exposures with DI falling within previously published control limits for DI and descriptive statistics were calculated. Results: DI data from 505,930 radiographic exposures was analyzed. The number of exposures with DI falling within published control limits for DI varied from 10 to 20% for adult patients and 10 to 23% for pediatric patients for different body parts and views. Mean DI values averaged over other parameters for radiographs of the abdomen, chest, pelvis, and extremities ranged from 0.3 to 1.0, −0.6 to 0.5, 0.8, and −0.9 to 0.5 for the different adult views and ranged from −1.6 to −0.1, −0.3 to 0.5, −0.1, −0.2 to 1.4 for the different pediatric views, respectively (DI data was solicited only for anteroposterior view of pelvis). Standard deviation values of DI from individual sites ranged from 1.3 to 3.6 and 1.3 to 3.0 for the different adult and pediatric views, respectively. Also of interest was that target exposure indicators varied by up to a factor of 6 between sites for certain body parts and views. Conclusion: Previously published DI control limits do not reflect the state of clinical practice in digital radiography. Mean DI and target exposure indicators are targets for quality improvement efforts in radiography.

  10. TU-FG-209-08: Distribution of the Deviation Index (DI) in Digital Radiography Practices Across the United States

    International Nuclear Information System (INIS)

    Jones, A; Shepard, S; Dave, J; Fisher, R; Hulme, K; Rill, L; Zamora, D; Woodward, A; Brady, S; MacDougall, R; Goldman, L; Lang, S; Peck, D; Apgar, B; Uzenoff, R; Willis, C

    2016-01-01

    Purpose: To characterize the distribution of the deviation index (DI) in digital radiography practices across the United States. Methods: DI data was obtained from 10 collaborating institutions in the United States between 2012 and 2015. Each institution complied with the requirements of the Institutional Review Board at their site. DI data from radiographs of the body parts chest, abdomen, pelvis and extremity were analyzed for anteroposterior, posteroanterior, lateral, and decubitus views. The DI data was analyzed both in aggregate and stratified by exposure control method, image receptor technology, patient age, and participating site for each body part and view. The number of exposures with DI falling within previously published control limits for DI and descriptive statistics were calculated. Results: DI data from 505,930 radiographic exposures was analyzed. The number of exposures with DI falling within published control limits for DI varied from 10 to 20% for adult patients and 10 to 23% for pediatric patients for different body parts and views. Mean DI values averaged over other parameters for radiographs of the abdomen, chest, pelvis, and extremities ranged from 0.3 to 1.0, −0.6 to 0.5, 0.8, and −0.9 to 0.5 for the different adult views and ranged from −1.6 to −0.1, −0.3 to 0.5, −0.1, −0.2 to 1.4 for the different pediatric views, respectively (DI data was solicited only for anteroposterior view of pelvis). Standard deviation values of DI from individual sites ranged from 1.3 to 3.6 and 1.3 to 3.0 for the different adult and pediatric views, respectively. Also of interest was that target exposure indicators varied by up to a factor of 6 between sites for certain body parts and views. Conclusion: Previously published DI control limits do not reflect the state of clinical practice in digital radiography. Mean DI and target exposure indicators are targets for quality improvement efforts in radiography.

  11. Comparison study on CNR and SNR of thoracic spine lateral radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Won [Dept. of Radiology, Samsung Medical Center, Seoul (Korea, Republic of); Min, Jung Whan; Lyu, Kwang Yeul [Dept. of Radiology, Shingu University, Sungnam (Korea, Republic of); Kim, Jung Min [Dept. of Radiological Science, College of Health Science, Korea University, Seoul (Korea, Republic of); Jeong, Hei Woun [Dept. of Radiological Science, Beakseok Culture University, Cheonan (Korea, Republic of); Lee, Joo Ah [Dept. of Oncology, Catholic University of Korea Incheon St.Mary,s Hospital, Incheon (Korea, Republic of); Jung, Jae Hong [Dept. of Oncology, Soonchunhyang University Bucheon Hospital, Bucheon (Korea, Republic of); Sung, Dong Chan [Dept. of Radiology, Dong Guk University Medical Center, Seoul (Korea, Republic of); Park, Soon Cheol [Dept. of Radiology, Kang Dong Kyung Hee University Medical Center, Seoul (Korea, Republic of)

    2013-12-15

    This study was proven for the T-spine breathing technique in lateral projection, using computer radiography (CR), charge coupled device (CCD), indirect digital radiography (IDR) and direct digital radiography (DDR). All images were evaluated and compared with CNR and SNR measured with the mean pixels and the standard deviation as setting ROI of spinous process, pedicle, vertebral body, intervertebral foramen and intervertebral disk using Image J. In experiment results of 4 type detectors, T-spine breathing technique was indicated as excellent in ROI of spinous process, pedicle, vertebral body, intervertebral foramen and intervertebral disk. As T-spine breathing technique indicated excellent images compared to the existing T-spine lateral radiography, this method would be useful for elderly patients who have difficulty in deep exhalation. This study was indicated the application possibility of T-spine breathing technique by presenting contrast to noise ratio (CNR) and signal to noise ratio (SNR) with quantitative value in 4 type detectors.

  12. Modeling Radiation Damage Effects in 3D Pixel Digitization for the ATLAS Detector

    CERN Document Server

    Giugliarelli, Gilberto; The ATLAS collaboration

    2017-01-01

    Silicon Pixel detectors are at the core of the current and planned upgrade of the ATLAS detector. As the detector in closest proximity to the interaction point, these detectors will be subjected to a significant amount of radiation over their lifetime: prior to the HL-LHC, the innermost layers will receive a fluence in excess of 10^15 neq/cm2 and the HL-LHC detector upgrades must cope with an order of magnitude higher fluence integrated over their lifetimes. This poster presents the details of a new digitization model that includes radiation damage effects to the 3D Pixel sensors for the ATLAS Detector.

  13. Modeling Radiation Damage Effects in 3D Pixel Digitization for the ATLAS Detector

    CERN Document Server

    Wallangen, Veronica; The ATLAS collaboration

    2017-01-01

    Silicon Pixel detectors are at the core of the current and planned upgrade of the ATLAS detector. As the detector in closest proximity to the interaction point, these detectors will be subjected to a significant amount of radiation over their lifetime: prior to the HL-LHC, the innermost layers will receive a fluence in excess of 10$^{15}$ n$_\\mathrm{eq}$/cm$^2$ and the HL-LHC detector upgrades must cope with an order of magnitude higher fluence integrated over their lifetimes. This work presents the details of a new digitization model that includes radiation damage effects to the 3D Pixel sensors for the ATLAS detector.

  14. Possibility of clinical usefulness of heavy metal filter combinations in digital chest radiography

    International Nuclear Information System (INIS)

    Kawaji, Yasuyuki; Ideguchi, Tadamitsu; Ikeda, Hirotaka; Sakamoto, Hiromi; Higashida, Yoshiharu; Toyofuku, Fukai

    2003-01-01

    We have investigated the potential usefulness of the heavy metal filters with higher atomic numbers by comparing their patient exposures, tube loadings, radiographic contrasts, and the visual detection of simulated nodules in computed radiography (CR) with those of a combination of copper and aluminum. Seven heavy metal filters were used for this study. As for a tungsten filter, two filters different in thickness were used. One is 0.05 mm thick, and the other 0.10 mm. The other metal filters were respectively combined with a tungsten filter with a thickness of 0.05 mm. Among the all filters, tungsten with 0.1 mm thick and tungsten with 0.05 mm+barium which showed larger advantages in patient exposure and tube loading than those of the other filters were used for detection task of simulated nodules in chest radiography. The results indicated that the use of heavy metal filters can improve detectability of simulated nodules over that obtainable with conventional copper and aluminum filter. (author)

  15. Standard practice for manufacturing characterization of digital detector arrays

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This practice describes the evaluation of Digital Detector Arrays (DDAs), and assures that one common standard exists for quantitative comparison of DDAs so that an appropriate DDA is selected to meet NDT requirements. 1.2 This practice is intended for use by manufacturers or integrators of DDAs to provide quantitative results of DDA characteristics for NDT user or purchaser consumption. Some of these tests require specialized test phantoms to assure consistency among results among suppliers or manufacturers. These tests are not intended for users to complete, nor are they intended for long term stability tracking and lifetime measurements. However, they may be used for this purpose, if so desired. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropr...

  16. A comparison between conventional radiography and digitized image accuracy in proximal caries detection

    Directory of Open Access Journals (Sweden)

    Pangnoosh M

    2003-08-01

    Full Text Available Statement of Problem: Computer Sciences, in radiology, like other fields, is of high importance. It should"nalso be noted that the accuracy of the technique and work conditions affects the radiographs information"nconsiderably. There for, in order to get more accurate diagnostic information, it seems necessary to investigate"ndifferent digitized radiographic techniques and to compare them with the conventional technique."nPurpose: The aim of this study was to compare the accuracy of conventional and digitized radiographic"nimages by three digitization techniques in proximal caries detection."nMaterial and Methods: In this research study, sixty extracted human canines, premolars and molars were"nmounted in blocks and imaged on E-Kodak film, similar to bitewing radiographs. Ten bitewing radiographs"nwere then scanned at 600 d.p.i with flat bed scanner and a digital camera, then digitized at 300 d.p.i with"nanother digital camera. The digitized images were displayed randomly on a high-resolution monitor. Six"nobservers assessed the caries status of 120 proximal surfaces by conventional and digitized images. The"nobserver's scores were compared with the results of the macroscopic examination. Reliability of each"ntechnique was calculated. Data were analyzed using chi-square and ANOVA tests."nResults: No significant differences were detected between different techniques in intact proximal surfaces and"nenamel caries diagnosis. However, digital techniques were more sensitive in dentin caries detection (P<0.05."nConclusions: When conventional film images are digitized, medium resolution (300 d.p.i seems to be"nsufficient. At this resolution the file size is decreased and there is no significant loss of the information"nnecessary for caries diagnosis.

  17. Application of X-ray digital radiography to online automated inspection of interior assembly structures of complex products

    International Nuclear Information System (INIS)

    Han Yueping; Han Yan; Li Ruihong; Wang Liming

    2009-01-01

    The paper proposes an application of X-ray digital radiography to online automated inspection and recognition of the interior assembly structures of complex products by means of the multiple views techniques. First, a vertical hybrid projection function (VHPF) is proposed as the recognition feature of a two-dimensional image. VHPF combines an integral projection function and a standard deviation function so that it can reflect the mean and the variance of the pixels in the vertical direction in an image. Secondly, by considering the different importance grades of objects inside the product and the independence of these objects along the circumference, the paper presents a hierarchical recognition method and uses a neural network system to speed up the computation process with parallel operations. Thirdly, using the whole-orientation features of one standard swatch and by extracting its maximal system of linear independence as the feature basis, the issue of blind areas for recognition is resolved. Based on this approach, the first domestic X-ray multi-view digital detection system has been developed and applied to the online detection of objects containing complicated assembly structures.

  18. Value of digital radiography in expiration in detection of pneumothorax; Wertigkeit der digitalen Roentgenaufnahme in Exspiration zum Nachweis eines Pneumothorax

    Energy Technology Data Exchange (ETDEWEB)

    Thomsen, L.; Natho, O.; Feigen, U.; Kivelitz, D. [Asklepios Klinik St. Georg, Hamburg (Germany). Dept. of Radiology; Schulz, U. [medistat GmbH, Kiel (Germany). Medical Statistics

    2014-03-15

    Purpose: The purpose of this study was to find out whether pneumothorax detection and exclusion is superior in expiratory digital chest radiography. Materials and Methods: 131 patients with pneumothorax with paired inspiratory and expiratory chest radiographs were analyzed regarding localization and size of pneumothorax. Sensitivity, specificity, negative (npv) and positive predictive value (ppv) as well as the positive (LR+) and negative likelihood ratio (LR-) were determined in a blinded randomized interobserver study with 116 patients. The evaluation was performed by three board-certified radiologists. Results: In 131 patients, there were 139 pneumothoraces, 135 (97.1 %) were located apical, 88 (63.3 %) lateral and 33 (23.7 %) basal. Sensitivity was 99 % for inspiratory and 97 % for expiratory radiographs. The interobserver study yielded a mean sensitivity of 86.1 %/86.1 %, specificity of 97.3 %/93.4 %, npv of 88.7 %/88.5 % and ppv of 96.7 %/92.1 % for inspiration/expiration. For inspiratory radiographs the LR+/LR- were 40.2/0.14 and for expiration 13.9 and 0.15. McNemar-Test showed no significant difference for the detection of pneumothoraces in in-/exspiration. Conclusion: Inspiratory and expiratory digital radiographs are equally suitable for pneumothorax detection. Inspiratory radiographs are recommended as the initial examination of choice for pneumothorax detection, an additional expiratory radiograph is only recommended in doubtful cases. (orig.)

  19. A comparative study of cone-beam computed tomography and digital periapical radiography in detecting mandibular molars root perforations

    Energy Technology Data Exchange (ETDEWEB)

    Haghanifar, Sina; Moudi, Ehsan; Mesgarani, Abbas; Abbaszadeh, Naghi [Dental Material Research Center, Dental Faculty, Babol University of Medical Sciences, Babol (Iran, Islamic Republic of); Bijani, Ali [Non-Communicable Pediatric Diseases Research Center, Babol University of Medical Sciences, Babol (Iran, Islamic Republic of)

    2014-06-15

    The aim of this in vitro study was to determine the sensitivity and specificity of cone-beam computed tomography (CBCT) and digital periapical radiography in the detection of mesial root perforations of mandibular molars. In this in vitro study, 48 mandibular molars were divided into 4 groups. First, the mesial canals of all the 48 teeth were endodontically prepared. In 2 groups (24 teeth each), the roots were axially perforated in the mesiolingual canal 1-3 mm below the furcation region, penetrating the root surface ({sup r}oot perforation{sup )}. Then, in one of these 2 groups, the mesial canals were filled with gutta-percha and AH26 sealer. Mesial canals in one of the other 2 groups without perforation (control groups) were filled with the same materials. The CBCT and periapical radiographs with 3 different angulations were evaluated by 2 oral and maxillofacial radiologists. The specificity and sensitivity of the two methods were calculated, and P<0.05 was considered significant. The sensitivity and specificity of CBCT scans in the detection of obturated root canal perforations were 79% and 96%, respectively, and in the case of three-angled periapical radiographs, they were 92% and 100%, respectively. In non-obturated root canals, the sensitivity and specificity of CBCT scans in perforation detection were 92% and 100%, respectively, and for three-angled periapical radiographs, they were 50% and 96%, respectively. For perforation detection in filled-root canals, periapical radiography with three different horizontal angulations would be trustworthy, but it is recommended that CBCT be used for perforation detection before obturating root canals.

  20. Diagnostic Accuracy of CBCT with Different Voxel Sizes and Intraoral Digital Radiography for Detection of Periapical Bone Lesions: An Ex-Vivo Study

    Directory of Open Access Journals (Sweden)

    Shirin Sakhdari

    2016-10-01

    Full Text Available Objectives: This study sought to assess the diagnostic accuracy of cone beam computed tomography (CBCT with different voxel sizes and intraoral digital radiography with photostimulable phosphor (PSP plate for detection of periapical (PA bone lesions.Materials and Methods: In this ex vivo diagnostic study, one-millimeter defects were created in the alveolar sockets of 15 bone blocks, each with two posterior teeth. A no-defect control group was also included. Digital PA radiographs with PSP plates and CBCT scans with 200, 250 and 300μ voxel sizes were obtained. Four observers evaluated the possibility of lesion detection using a 5-point scale. Sensitivity, specificity, positive predictive value (PPV and negative predicative value (NPV were analyzed using one-way ANOVA and Tamhane’s post hoc test. Kappa and weighted kappa statistics were applied to assess intraobserver and interobserver agreements.Results: Cochrane Q test showed no significant difference between PSP and CBCT imaging modalities in terms of kappa and weighted kappa statistics (P=0.675. The complete sensitivity and complete NPV for 200 and 250 μ voxel sizes were higher than those of 300 μ voxel size and digital radiography (P<0.001. No significant difference was noted in other parameters among other imaging modalities (P=0.403.Conclusions: The results showed that high-resolution CBCT scans had higher diagnostic accuracy than PSP digital radiography for detection of artificially created PA bone lesions. Voxel size (field of view must be taken into account to minimize patient radiation dose.Keywords: Diagnosis; Cone-Beam Computed Tomography; Radiography, Dental, Digital; Periapical Periodontitis

  1. Optimization of dual-energy subtraction chest radiography by use of a direct-conversion flat-panel detector system.

    Science.gov (United States)

    Fukao, Mari; Kawamoto, Kiyosumi; Matsuzawa, Hiroaki; Honda, Osamu; Iwaki, Takeshi; Doi, Tsukasa

    2015-01-01

    We aimed to optimize the exposure conditions in the acquisition of soft-tissue images using dual-energy subtraction chest radiography with a direct-conversion flat-panel detector system. Two separate chest images were acquired at high- and low-energy exposures with standard or thick chest phantoms. The high-energy exposure was fixed at 120 kVp with the use of an auto-exposure control technique. For the low-energy exposure, the tube voltages and entrance surface doses ranged 40-80 kVp and 20-100 % of the dose required for high-energy exposure, respectively. Further, a repetitive processing algorithm was used for reduction of the image noise generated by the subtraction process. Seven radiology technicians ranked soft-tissue images, and these results were analyzed using the normalized-rank method. Images acquired at 60 kVp were of acceptable quality regardless of the entrance surface dose and phantom size. Using a repetitive processing algorithm, the minimum acceptable doses were reduced from 75 to 40 % for the standard phantom and to 50 % for the thick phantom. We determined that the optimum low-energy exposure was 60 kVp at 50 % of the dose required for the high-energy exposure. This allowed the simultaneous acquisition of standard radiographs and soft-tissue images at 1.5 times the dose required for a standard radiograph, which is significantly lower than the values reported previously.

  2. Filmless Radiography

    Science.gov (United States)

    1997-01-01

    Technology initially prototyped under a Small Business Innovation Research contract between Quantex Corporation and Langley Research Center was licensed to Liberty Technology and incorporated into RADView, a new filmless radiography technology. The NASA-sponsored work involved the investigation of Electron Trapping, which led to a solid-state film that uses a special class of photoluminescent materials to capture radiographic images. RadView is a total imaging solution for the conversion of radiographic film records to digital format and digital acquisitions of radiographs. With the RADView technology, there is a reduction of exposure times and errors; film waste is eliminated; and the efficiency of data management and precise image analysis is boosted. The solid-state film can be exposed, read, erased, and re- exposed indefinitely until mechanical replacement is required. Digital images can be stored to optical media for up to 100 years and beyond without information loss.

  3. Application of MOSFET detectors for dosimetry in small animal radiography using short exposure times.

    Science.gov (United States)

    De Lin, Ming; Toncheva, Greta; Nguyen, Giao; Kim, Sangroh; Anderson-Evans, Colin; Johnson, G Allan; Yoshizumi, Terry T

    2008-08-01

    Digital subtraction angiography (DSA) X-ray imaging for small animals can be used for functional phenotyping given its ability to capture rapid physiological changes at high spatial and temporal resolution. The higher temporal and spatial requirements for small-animal imaging drive the need for short, high-flux X-ray pulses. However, high doses of ionizing radiation can affect the physiology. The purpose of this study was to verify and apply metal oxide semiconductor field effect transistor (MOSFET) technology to dosimetry for small-animal diagnostic imaging. A tungsten anode X-ray source was used to expose a tissue-equivalent mo