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Sample records for digital radiographic detector

  1. 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

  2. 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

  3. Digital image analysis of NDT radiographs

    International Nuclear Information System (INIS)

    Graeme, W.A. Jr.; Eizember, A.C.; Douglass, J.

    1989-01-01

    Prior to the introduction of Charge Coupled Device (CCD) detectors the majority of image analysis performed on NDT radiographic images was done visually in the analog domain. While some film digitization was being performed, the process was often unable to capture all the usable information on the radiograph or was too time consuming. CCD technology now provides a method to digitize radiographic film images without losing the useful information captured in the original radiograph in a timely process. Incorporating that technology into a complete digital radiographic workstation allows analog radiographic information to be processed, providing additional information to the radiographer. Once in the digital domain, that data can be stored, and fused with radioscopic and other forms of digital data. The result is more productive analysis and management of radiographic inspection data. The principal function of the NDT Scan IV digital radiography system is the digitization, enhancement and storage of radiographic images

  4. 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

  5. Digitization of conventional radiographs

    International Nuclear Information System (INIS)

    Wenz, W.; Buitrago-Tellez, C.; Blum, U.; Hauenstein, K.H.; Gufler, H.; Meyer, E.; Ruediger, K.

    1992-01-01

    The diagnostic value of a digitization system for analogue films based on a charge-coupled-device (CCD) scanner with adjustable resolution of 2.5 or 5 lp/mm was assessed. Some 110 skeletal radiographs, 50 contrast studies, including 25 of patients with Crohn's disease, and 70 abdominal plain films before and after successful lithotripsy for renal stones were digitized. Receiver operating characteristic (ROC) studies showed improved detection of cortical and trabecular defects with contrast-optimized digitized films. Edge enhancement algorithms yielded no additional information. Inflammatory lesions of Crohn's disease were detected equally well by conventional films and digitized images. A statistically significant improvement (p [de

  6. Radiographic film digitizing devices

    International Nuclear Information System (INIS)

    McFee, W.H.

    1988-01-01

    Until recently, all film digitizing devices for use with teleradiology or picture archiving and communication systems used a video camera to capture an image of the radiograph for subsequent digitization. The development of film digitizers that use a laser beam to scan the film represents a significant advancement in digital technology, resulting in improved image quality compared with video scanners. This paper discusses differences in resolution, efficiency, reliability, and the cost between these two types of devices. The results of a modified receiver operating characteristic comparison study of a video scanner and a laser scanner manufactured by the same company are also discussed

  7. Resolution requirements for monitor viewing of digital flat-panel detector radiographs: a contrast detail analysis

    International Nuclear Information System (INIS)

    Peer, Siegfried; Giacomuzzi, Salvatore M.; Peer, Regina; Gassner, Eva; Steingruber, Iris; Jaschke, Werner

    2003-01-01

    With the introduction of digital flat-panel detector systems into clinical practice, the still unresolved question of resolution requirements for picture archiving communication system (PACS) workstation monitors has gained new momentum. This contrast detail analysis was thus performed to define the differences in observer performance in the detection of small low-contrast objects on clinical 1K and 2K monitor workstations. Images of the CDRAD 2.0 phantom were acquired at varying exposures on an indirect-type digital flat-panel detector. Three observers evaluated a total of 15 images each with respect to the threshold contrast for each detail size. The numbers of correctly identified objects were determined for all image subsets. No significant difference in the correct detection ratio was detected among the observers; however, the difference between the two types of workstations (1K vs 2K monitors) despite less than 3% was significant at a 95% confidence level. Slight but statistically significant differences exist in the detection of low-contrast nodular details visualized on 1K- and 2K-monitor workstations. Further work is needed to see if this result holds true also for comparison of clinical flat-panel detector images and may, for example, exert an influence on the diagnostic accuracy of chest X-ray readings. (orig.)

  8. Small animals bone density and morphometry analysis with a dual energy X-rays absorptiometry bone densitometer using a 2D digital radiographic detector

    International Nuclear Information System (INIS)

    Boudousq, V.; Bordy, T.; Gonon, G.; Dinten, J.M.

    2004-01-01

    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 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)

  9. Digitization of radiographic inspection for pipeline girth welded joints

    International Nuclear Information System (INIS)

    Uemura, Shimpei

    2016-01-01

    In radiographic inspection for the girth welded joints of natural gas pipeline, film radiographic testing (FRT) is applied presently in Japan. However, as of July 2016, the work of establishing JIS standard for radiographic inspection with digital detector is in progress. In order to provide users with the merit of digitization as soon as possible, the authors have developed NSDART (Nittetsu-Sumikin digital detector array technology) as a field X-ray inspection system for the girth welded joints of pipeline. This paper reports the required performances discussed in face of development of NSDART, selection of digital detector, and outline of NSDART, and shows part of the radiographic images acquired with NSDART. As required performances, the following were established: (1) required image quality for radiographic image, (2) identifiable minimum wire diameter of transmission meter, (3) density range of radiographic image and value of gradation meter, (4) spatial resolution via Duplex Wire, (5) X-ray generator, (6) real time performance, and (7) display for observing radiographic image. As for the selection of digital detector, flat panel detector was judged to be the most suitable, and its incorporation to NSDART was determined. NSDART devices are composed of a magnet-wheeled self-propelled imaging device, personal computer, controller, and externally installed display for judgment. (A.O.)

  10. Radiographic techniques for digital mammography

    International Nuclear Information System (INIS)

    Horita, Katsuhei

    2007-01-01

    Since the differences in X-ray absorption between various breast tissues are small, a dedicated X-ray system for examination of the breast and a high-contrast, high-resolution screen/film system (SFM) (light-receiving system) are employed for X-ray diagnosis. Currently, however, there is a strong trend toward digital imaging in the field of general radiography, and this trend is also reflected in the field of mammographic examination. In fact, approximately 70% of facilities purchasing new mammography systems are now selecting a digital mammography system (DRM). Given this situation, this report reviews the differences between SFM and DRM and discusses the radiographic techniques and quality assurance procedures for digital mammography. (author)

  11. Digital processing of radiographic images

    Science.gov (United States)

    Bond, A. D.; Ramapriyan, H. K.

    1973-01-01

    Some techniques are presented and the software documentation for the digital enhancement of radiographs. Both image handling and image processing operations are considered. The image handling operations dealt with are: (1) conversion of format of data from packed to unpacked and vice versa; (2) automatic extraction of image data arrays; (3) transposition and 90 deg rotations of large data arrays; (4) translation of data arrays for registration; and (5) reduction of the dimensions of data arrays by integral factors. Both the frequency and the spatial domain approaches are presented for the design and implementation of the image processing operation. It is shown that spatial domain recursive implementation of filters is much faster than nonrecursive implementations using fast fourier transforms (FFT) for the cases of interest in this work. The recursive implementation of a class of matched filters for enhancing image signal to noise ratio is described. Test patterns are used to illustrate the filtering operations. The application of the techniques to radiographic images of metallic structures is demonstrated through several examples.

  12. Digital interactive learning of oral radiographic anatomy.

    Science.gov (United States)

    Vuchkova, J; Maybury, T; Farah, C S

    2012-02-01

    Studies reporting high number of diagnostic errors made from radiographs suggest the need to improve the learning of radiographic interpretation in the dental curriculum. Given studies that show student preference for computer-assisted or digital technologies, the purpose of this study was to develop an interactive digital tool and to determine whether it was more successful than a conventional radiology textbook in assisting dental students with the learning of radiographic anatomy. Eighty-eight dental students underwent a learning phase of radiographic anatomy using an interactive digital tool alongside a conventional radiology textbook. The success of the digital tool, when compared to the textbook, was assessed by quantitative means using a radiographic interpretation test and by qualitative means using a structured Likert scale survey, asking students to evaluate their own learning outcomes from the digital tool. Student evaluations of the digital tool showed that almost all participants (95%) indicated that the tool positively enhanced their learning of radiographic anatomy and interpretation. The success of the digital tool in assisting the learning of radiographic interpretation is discussed in the broader context of learning and teaching curricula, and preference (by students) for the use of this digital form when compared to the conventional literate form of the textbook. Whilst traditional textbooks are still valued in the dental curriculum, it is evident that the preference for computer-assisted learning of oral radiographic anatomy enhances the learning experience by enabling students to interact and better engage with the course material. © 2011 John Wiley & Sons A/S.

  13. A new system for fully automatic inspection of digital flat-panel detector radiographs of aluminium castings

    International Nuclear Information System (INIS)

    Fuchs, T.; Hassler, U.; Huetten, U.; Wenzel, T.

    2006-01-01

    The aim of our work was the integration of various newly-developed methods into a system for fully automatic radioscopic inspection of arbitrary casting parts. Using a 16-bit flat-panel detector, projections in arbitrary directions through the part are acquired and analysed. The software tool for inspection can be separated into five stages: registration, calibration, image processing, fault segmentation, and quality assessment. Thereby, each step is realized with full 16-bit data processing. Within the first processing stage, information about the physical length and density of the aluminium structures is extracted from the primary projections. Next, the primary image is registered with a reference image, which was acquired previously. Afterwards, the third stage combines both reference image-based and reference-less testing. A filter is applied, which adapts automatically to the local object structure by referring to the properties of the reference. Thereby, the self-adapting filter selects its size, direction and filter method optimally according to the local situation. Similar to the reference-less procedure, a subtraction is followed by a threshold operation, resulting in a map of regions that are suspected to be faulty. The fourth step aims at an elimination of false-positive detections. Again, two methods are applied successively: evaluation of local image features at suspicious positions and a classification based on teachings independent of position and orientation of the faults. Within the last step the quality criteria are applied. These criteria may concern fault size and depth, the density of faults in critical regions and a minimum distance between two or more faults. (orig.)

  14. Development of low-silver radiographic detectors

    International Nuclear Information System (INIS)

    Troitskij, V.A.; Novikov, I.A.; Nikitin, V.F.; Krasnyj-Admoni, L.V.; Valevich, M.I.; Belyj, N.G.; Grom, V.S.

    1988-01-01

    The results of investigations on radiographic testing of welded joints of St20, 08Kh18N10T steels, the AMG-6 alloy, copper, titanium using radiographic detectors with the low silver content are presented. The roentgenographic and photographic paper, as well as the samples of experimental films with heavy elements in the photolayer are tested using intensifying screens of different types. Experimental films containing silver 2 times as less as standard X-ray films are shown to provide the similar sensitivity of testing under equal conditions, but the exposure time is two times higher. Prints on the radiophotographic paper in quality and exposure time approach to prints obtained on the RT-1 film containing silver 10 times less than that in the roentgenographic film. The exposure time of the radiographic paper is several times less than that of the ''unibrom'' contrast paper. The testing sensitivity decreases to some extent in this case

  15. Evaluation of underexposed conventional radiographs after digitization

    International Nuclear Information System (INIS)

    Wenz, W.

    1993-01-01

    Inadequate exposure of analogue radiographs is reported in the literature to occur in 5-25% of cases. Therefore, the present study was performed to test whether selective image processing after digitization could reveal diagnostic details on underexposed radiographs. In addition, the minimal exposure values required for diagnostic purposes after adequate image processing were studied. Phantom studies, organ preparations and measurements of physical parameters with decreasing exposure values were performed. The detection of anatomic and pathologic (nondisplaced fracture lines, microcalcification and renal stones) structures were evaluated by 12 readers. Radiographs with exposure values 20-40% lower than 'ideal' values can provide adequate diagnostic images after digital processing. The diagnostic information is significantly impaired with values under 50% of the correct exposure values. In conclusion, this method is adequate to save underexposed radiographs for diagnostic purposes and to avoid repeated examinations. (orig.) [de

  16. 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)

  17. Digital radiographic assessment of coronary flow reserve

    International Nuclear Information System (INIS)

    Vogel, R.A.

    1985-01-01

    A method for measuring relative changes in regional blood flow using digital radiographic enhancement of selective coronary arteriography. Coronary flow reserve is measured in individual arterial distributions using the washin ratio of contrast appearance time under baseline and hyperemic conditions. Information is quantitatively presented in functional (parametric) image format. These images, termed contrast medium appearance pictures (CMAP), depict the transit of contrast through the arterial, myocardial and early venous stages. This process can be divided into three general phases: data acquisition, CMAP formation and CMAP analysis. The technique has evolved over its development period from a cine film-based technology which required substantial processing time to a real-time digital radiographic technique

  18. Image quality in digital radiographic systems

    Directory of Open Access Journals (Sweden)

    Almeida Solange Maria de

    2003-01-01

    Full Text Available The aim of the present study was to evaluate the image quality of four direct digital radiographic systems. Radiographs were made of the maxillary central incisor and mandibular left molar regions of a dry skull, and an aluminum step-wedge. The X-ray generator operated at 10 mA, 60 and 70 kVp, and images were acquired with 3, 5, 8, 12, 24 and 48 exposure pulses. Six well-trained observers classified the images by means of scores from 1 to 3. Collected data were submitted to nonparametric statistical analysis using Fisher's exact test. Statistical analysis showed significant differences (p<0.01 in image quality with the four systems. Based on the results, it was possible to conclude that: 1 all of the digital systems presented good performance in producing acceptable images for diagnosis, if the exposures of the step-wedge and the maxillary central incisor region were made at 5 pulses, as well as at 8 pulses for the mandibular left molar region, selecting 60 or 70kVp; 2 higher percentages of acceptable images were obtained with the administration of lower radiation doses in CCD-sensors (charge-coupled device; 3 the Storage Phosphor systems produced acceptable images at a large range of exposure settings, that included low, intermediate and high radiation doses.

  19. Segmentation of ribs in digital chest radiographs

    Science.gov (United States)

    Cong, Lin; Guo, Wei; Li, Qiang

    2016-03-01

    Ribs and clavicles in posterior-anterior (PA) digital chest radiographs often overlap with lung abnormalities such as nodules, and cause missing of these abnormalities, it is therefore necessary to remove or reduce the ribs in chest radiographs. The purpose of this study was to develop a fully automated algorithm to segment ribs within lung area in digital radiography (DR) for removal of the ribs. The rib segmentation algorithm consists of three steps. Firstly, a radiograph was pre-processed for contrast adjustment and noise removal; second, generalized Hough transform was employed to localize the lower boundary of the ribs. In the third step, a novel bilateral dynamic programming algorithm was used to accurately segment the upper and lower boundaries of ribs simultaneously. The width of the ribs and the smoothness of the rib boundaries were incorporated in the cost function of the bilateral dynamic programming for obtaining consistent results for the upper and lower boundaries. Our database consisted of 93 DR images, including, respectively, 23 and 70 images acquired with a DR system from Shanghai United-Imaging Healthcare Co. and from GE Healthcare Co. The rib localization algorithm achieved a sensitivity of 98.2% with 0.1 false positives per image. The accuracy of the detected ribs was further evaluated subjectively in 3 levels: "1", good; "2", acceptable; "3", poor. The percentages of good, acceptable, and poor segmentation results were 91.1%, 7.2%, and 1.7%, respectively. Our algorithm can obtain good segmentation results for ribs in chest radiography and would be useful for rib reduction in our future study.

  20. High-frame-rate digital radiographic videography

    Science.gov (United States)

    King, Nicholas S. P.; Cverna, Frank H.; Albright, Kevin L.; Jaramillo, Steven A.; Yates, George J.; McDonald, Thomas E.; Flynn, Michael J.; Tashman, Scott

    1994-10-01

    High speed x-ray imaging can be an important tool for observing internal processes in a wide range of applications. In this paper we describe preliminary implementation of a system having the eventual goal of observing the internal dynamics of bone and joint reactions during loading. Two Los Alamos National Laboratory (LANL) gated and image intensified camera systems were used to record images from an x-ray image convertor tube to demonstrate the potential of high frame-rate digital radiographic videography in the analysis of bone and joint dynamics of the human body. Preliminary experiments were done at LANL to test the systems. Initial high frame-rate imaging (from 500 to 1000 frames/s) of a swinging pendulum mounted to the face of an X-ray image convertor tube demonstrated high contrast response and baseline sensitivity. The systems were then evaluated at the Motion Analysis Laboratory of Henry Ford Health Systems Bone and Joint Center. Imaging of a 9 inch acrylic disk with embedded lead markers rotating at approximately 1000 RPM, demonstrated the system response to a high velocity/high contrast target. By gating the P-20 phosphor image from the X-ray image convertor with a second image intensifier (II) and using a 100 microsecond wide optical gate through the second II, enough prompt light decay from the x-ray image convertor phosphor had taken place to achieve reduction of most of the motion blurring. Measurement of the marker velocity was made by using video frames acquired at 500 frames/s. The data obtained from both experiments successfully demonstrated the feasibility of the technique. Several key areas for improvement are discussed along with salient test results and experiment details.

  1. Digital subtraction radiographic evaluation of the standardize periapical intraoral radiographs

    International Nuclear Information System (INIS)

    Cho, Bong Hae; Nah, Kyung Soo

    1993-01-01

    The geometrically standardized intraoral radiographs using 5 occlusal registration material were taken serially from immediate, 1 day, 2, 4, 8, 12 and 16 weeks after making the bite blocks. The qualities of those subtracted images were evaluated to check the degree of reproducibility of each impression material. The results were as follows: 1. The standard deviations of the grey scales of the overall subtracted images were 4.9 for Exaflex, 7.2 for Pattern resin, 9.0 for Tooth Shade Acrylic, 12.2 for XCP only, 14.8 for Impregum. 2. The standard deviation of the grey scales of the overall subtracted images were grossly related to those of the localized horizontal line of interest. 3. Exaflex which showed the best subtracted image quality had 15 cases of straight, 14 cases of wave, 1 case of canyon shape. Impregum which showed the worst subtracted image quality had 4 cases of straight, 8 cases of wave, 18 cases of canyon shape respectively.

  2. Digital radiographic techniques in the analysis of paintings

    International Nuclear Information System (INIS)

    James, A.E. Jr.; Gibbs, S.J.; James, A.E. III; Pickens, D.R.; Sloan, M.; Price, R.R.; Erickson, J.J.

    1985-01-01

    In this chapter the authors use the term digital radiography to mean any method of radiographic image production in which the silver halide-based film is replaced by an electronic sensor for production of an image. There are essentially three types of digital radiographic systems available at present, but others will be developed. These differ primarily in the method of image production and the rapidity with which images can be produced. The three methods discussed are digital fluoroscopy, scanned projection radiography, and the scanned point source radiography. Each has certain characteristics which, if properly utilized, will allow improved x-ray analysis of paintings

  3. Implementation of a dedicated digital projectional radiographic system in thoracic imaging

    International Nuclear Information System (INIS)

    Aberle, D.R.; Batra, P.; Hayrapetian, A.S.; Brown, K.; Morioka, C.A.; Steckel, R.J.

    1988-01-01

    An integrated digital radiographic system was evaluated with respect to image quality and impact on diagnosis relative to conventional chest radiographs for a variety of focal and diffuse lung processes. Digital images were acquired with a stimulable phosphor plate detector that was scanned by a semiconductor laser for immediate digitalization to a 2,048 X 2,464 X 10-bit image. Digital images were displayed on a 2,048-line monitor and printed on 14 X 17-inch film with use of a laser film printer (Kodak). Preliminary results with this system, including the effects of user interaction with the display monitor, inverse intensity display, and regional magnification techniques, indicate that it may be successfully implemented for thoracic imaging

  4. 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

  5. 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.

  6. Analysis of several ways to minimize the scatter contribution in radiographic digital images of offshore pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Edmilson M.; Silva, Ademir X.; Lopes, Ricardo T., E-mail: emonteiro@nuclear.ufrj.b, E-mail: ademir@nuclear.ufrj.b, E-mail: Ricardo@lin.ufrj.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Correa, Samanda C.A., E-mail: scorrea@cnen.gov.b [Comissao Nacional de Energia Nuclear (DIAPI/CGMI/CNEN), Rio de Janeiro, RJ (Brazil). Coordenacao Geral de Instalacoes Medicas e Industriais. Div. de Aplicacoes Industriais

    2011-07-01

    The aim of this work is to evaluate, through MCNPX simulations, several ways to minimize the scatter contribution in radiographic digital images of offshore pipelines. The influence of liquid inside the pipes and water surrounded the pipelines in the scatter contribution will be analyzed. The use of lead screen behind the detector to reduce the backscattered radiation and filter between the radiation source and the pipes will be discussed. (author)

  7. Analysis of several ways to minimize the scatter contribution in radiographic digital images of offshore pipelines

    International Nuclear Information System (INIS)

    Souza, Edmilson M.; Silva, Ademir X.; Lopes, Ricardo T.; Correa, Samanda C.A.

    2011-01-01

    The aim of this work is to evaluate, through MCNPX simulations, several ways to minimize the scatter contribution in radiographic digital images of offshore pipelines. The influence of liquid inside the pipes and water surrounded the pipelines in the scatter contribution will be analyzed. The use of lead screen behind the detector to reduce the backscattered radiation and filter between the radiation source and the pipes will be discussed. (author)

  8. 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

  9. Direct digital acquisition of neonatal portable chest radiographs

    International Nuclear Information System (INIS)

    Cohen, M.D.; Cory, D.A.; Broderick, N.J.; Smith, J.A.

    1987-01-01

    The Philips computerized radiography system utilizes a phosphor plate instead of an x-ray film to acquire radiographic images. The latent image on the plate is converted to a digital format. The authors report their initial experience with the system in more than 300 studies on intensive care neonates. The digital images provide very uniform image density. Tubes and catheters are more easily visualized than on conventional images. Soft tissues of the chest wall and bony structures are also more clearly seen on the digital images. The authors' initial experience indicates that portable digital imaging of neonates is technically feasible and provides good-quality diagnostic images

  10. Distortion of digital panoramic radiographs used for implant site assessment

    Directory of Open Access Journals (Sweden)

    Rayyan Abdulhamid Kayal

    2016-01-01

    Full Text Available Aims: This study is conducted to determine the amount of distortion of digital panoramic radiographs. Materials and Methods: Panoramic radiographs of all patients who received dental implants in the years 2012 and 2013 were selected from the records at the faculty of dentistry, King Abdulaziz University. Radiographs were analyzed using the R4 Kodak Software for linear measurements of implants length and width. The measurements were compared to the actual size of the implant, and the amount of distortion was calculated. Results: A total of 169 implants were analyzed. Horizontally, there was a statistically significant increase of 0.4 mm in width in the radiographic measurement compared to the actual size in the incisor region. Vertically, the sample overall exhibited a decrease by 0.4 mm compared to the actual size. Incisors had the highest difference with a decrease of 1.7 mm in the radiographic measurements compared to actual size. The highest distortion was found in the incisor region for both diameter and length (1.1 and 0.86, respectively. Conclusion: Digital panoramic radiographs show minimal to no distortion. The highest distortion is found in the anterior area.

  11. Digital image processing of mandibular trabeculae on radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Ogino, Toshi

    1987-06-01

    The present study was aimed to reveal the texture patterns of the radiographs of the mandibular trabeculae by digital image processing. The 32 cases of normal subjects and the 13 cases of patients with mandibular diseases of ameloblastoma, primordial cysts, squamous cell carcinoma and odontoma were analyzed by their intra-oral radiographs in the right premolar regions. The radiograms were digitized by the use of a drum scanner densitometry method. The input radiographic images were processed by a histogram equalization method. The result are as follows : First, the histogram equalization method enhances the image contrast of the textures. Second, the output images of the textures for normal mandible-trabeculae radiograms are of network pattern in nature. Third, the output images for the patients are characterized by the non-network pattern and replaced by the patterns of the fabric texture, intertwined plants (karakusa-pattern), scattered small masses and amorphous texture. Thus, these results indicates that the present digital image system is expected to be useful for revealing the texture patterns of the radiographs and in the future for the texture analysis of the clinical radiographs to obtain quantitative diagnostic findings.

  12. Application of digital techniques to the restoration of radiographic images

    International Nuclear Information System (INIS)

    Burch, S.F.

    1980-09-01

    The methods of constrained least squares and maximum entropy have been used to restore digital X and γ-ray radiographs. Both methods require the blurring of the image to be a linear, spatially invariant process. Although the blurring processes in radiography can be complex, situations have been identified where these simplifying assumptions are valid. Algorithms for deriving the point-spread function of each image are discussed. These include a pinhole method for X-ray radiographs, and reconstruction from edge profiles for γ-ray radiographs. The results from the restoration of geometrically blurred radiographs of sparking plugs are given. Maximum entropy gives results superior to those obtained by constrained least squares. The resolution is improved by a factor of about three when maximum entropy is used, and by a factor of about two for constrained least squares. (author)

  13. Evaluation of the styloid process on digital panoramic radiographs

    International Nuclear Information System (INIS)

    More, Chandramani B; Asrani, Mukesh K

    2010-01-01

    The styloid process is an anatomical structure, whose clinical importance is not well understood. Proper clinical and radiographic evaluation can detect an elongated styloid process and calcification of the stylohyoid ligament. It has been reported that 2 – 28% of the general population show radiographic evidence of mineralization of a portion of the stylohyoid chain. The elongated styloid process may be symptomatic in many cases. Panoramic radiography is the best imaging modality to view the styloid process bilaterally. To assess the styloid process on digital panoramic radiographs. The study was conducted on 500 digital panoramic radiographs available in the archives of our department as soft copies. These radiographs were taken using a digital panoramic system. The radiographic length of the styloid process was measured on both sides using the measurement toolbars on the accompanying analysis software. For statistical analysis we used the unpaired t test, Chi-square test, and one-way ANOVA test, as necessary. The average length of the left styloid was 25.41 ± 6.32 mm and that of the right styloid was 25.53 ± 6.62 mm. The length of both styloids increased with age and males had longer styloids than females. Elongated styloids were present in 19.4% of the panoramic radiographs. Langlais type I elongated styloids and a partial calcification pattern were more common than others. Panoramic radiography is useful for detection of an elongated styloid process and / or ossification of the stylohyoid ligament in patients with or without symptoms, and helps avoid a misdiagnosis of tonsillar pain or pain of dental, pharyngeal, or muscular origin

  14. Evaluation of the styloid process on digital panoramic radiographs

    Directory of Open Access Journals (Sweden)

    More Chandramani

    2010-01-01

    Full Text Available Background: The styloid process is an anatomical structure, whose clinical importance is not well understood. Proper clinical and radiographic evaluation can detect an elongated styloid process and calcification of the stylohyoid ligament. It has been reported that 2 - 28% of the general population show radiographic evidence of mineralization of a portion of the stylohyoid chain. The elongated styloid process may be symptomatic in many cases. Panoramic radiography is the best imaging modality to view the styloid process bilaterally. Aim: To assess the styloid process on digital panoramic radiographs. Materials and Methods: The study was conducted on 500 digital panoramic radiographs available in the archives of our department as soft copies. These radiographs were taken using a digital panoramic system. The radiographic length of the styloid process was measured on both sides using the measurement toolbars on the accompanying analysis software. For statistical analysis we used the unpaired t test, Chi-square test, and one-way ANOVA test, as necessary. Results: The average length of the left styloid was 25.41 ± 6.32 mm and that of the right styloid was 25.53 ± 6.62 mm. The length of both styloids increased with age and males had longer styloids than females. Elongated styloids were present in 19.4% of the panoramic radiographs. Langlais type I elongated styloids and a partial calcification pattern were more common than others. Conclusion: Panoramic radiography is useful for detection of an elongated styloid process and / or ossification of the stylohyoid ligament in patients with or without symptoms, and helps avoid a misdiagnosis of tonsillar pain or pain of dental, pharyngeal, or muscular origin.

  15. Obtaining digital files from radiographic films

    International Nuclear Information System (INIS)

    Lavena, Leonardo B; Romero, Amanda G; Paul, Anibal de; Rocha, Luis A; Rotger, Viviana I; Olivera, Juan M

    2007-01-01

    Digitizing images with low cost off-the-shelf technology arises as an alternative to storage films in developing countries. The objective of this work is to determine a low-cost method to digitize Rx films for educative and remote-consult purposes. To this aim, different ways of digitizing were compared against conventional methods to determine the feasibility to have a simple-low cost method that is quality independent from facilities and operator. Different images from digital photo cameras and scanners (with or without transparency adapter at different resolutions and color depth) were analyzed. We present preliminary results for digitizing Rx films with a fast and simple inexpensive system that capture quality images, and optimal sizes for storage in basic PCs in hospitals, with the possibility of asking for a second opinion via e-mail or through a web-based service. It must be noted that in many cases the only way of communication is via dial-up telephone line

  16. Digital radiographic technology; non-destructive testing of tubine blades

    NARCIS (Netherlands)

    Penumadu, P.S.

    2014-01-01

    Inspection of turbine blades has always been a big challenge. Any irregularities in the blade have a huge impact on the gas turbine, so these blades have to be manufactured and inspected in the most sophisticated way possible. The evolution of digital radiographic technology took a leap forward to

  17. Dose reduction of radiographs of the pediatric pelvis for diagnosing hip dysplasia using a digital flat-panel detector system; Dosisreduktion bei Roentgenaufnahmen des kindlichen Beckenskelettes zur Diagnostik der Hueftgelenksdysplasie unter Verwendung eines digitalen Flachdetektorsystems

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, K.; Ahlers, K.; Kloska, S.; Vieth, V.; Meier, N.; Heindel, W. [Inst. fuer Klinische Radiologie, Westfaelische Wilhelms-Univ. Muenster (Germany); Sandmann, C.; Gosheger, G. [Orthopaedische Klinik, Westfaelische Wilhelms-Univ. Muenster (Germany)

    2003-01-01

    Purpose: To evaluate a possible dose reduction in pediatric pelvic radiographs in congenital hip dysplasia using a digital flat-panel system instead of a phosphor-storage system. Materials and Methods: During a six-month period, all pediatric patients referred for pelvic radiography for the evaluation of congenital hip dysplasia were randomely assigned to be examined by either a phosphor-storage system or a digital flat-panel system, whereby the latter system was operated with half the radiation dose. Thirty pairs of radiographs were assessed for the visibility of 16 anatomic details and for 5 orthopedic-radiographic measurements (5-point scale with 1 = excellent; three independent observers). The projection indices of Ball and Kommenda and of Toennis and Brunken were calculated for all radiographs. The Student's t-test was used to compare the flat-panel and the phosphor-storage radiographs for observers' assessments, patients' age and projection indices. Results: In a total of 7560 observations, the scores for the visibility of anatomic details and orthopedic-radiographic measurements were respectively 2.72 and 2.64 for the flat-panel system and 2.93 and 2.79 for the phosphor-storage system. No significant differences were found between both systems (p > 0.05) and between patient age and projection indices (p > 0.05). Conclusion: Pediatric pelvic radiographs can be obtained with a digital flat-panel system using half the radiation dose instead of a phosphor-storage system without sacrificing relevant information in the diagnosis of congenital hip dysplasia. (orig.) [German] Zielsetzung: Evaluation einer moeglichen Dosisreduktion bei kindlichen Beckenroentgenaufnahmen zur Diagnostik der Hueftgelenksdysplasie mit einem digitalen Flachdetektorsystem im Vergleich zu einem digitalen Speicherfoliensystem. Material und Methoden: Prospektiv wurden alle ueber einen Zeitraum von 6 Monaten zur Roentgenaufnahme des Beckenskelettes im Rahmen der Diagnostik der

  18. Proton radiographic characteristics of thin CR-39 detector

    International Nuclear Information System (INIS)

    Waheed, A.; Manzoor, S.; Khan, H.A.; Urlep, I.; Ilic, R.

    1991-01-01

    Two parameters, track registration sensitivity and densitometric response, were measured in radiography with a low energy (∼4.5 MeV) proton beam and a stack of thin (100μm) CR-39 detector foils. The optimum image quality was obtained at a layer removal thickness of about 1 μm. The image obtained under these conditions is characterized by a high track registration sensitivity (∼60%), high image contrast (the maximum value of the net optical density is ∼0.7) and high spatial resolution (∼1 μm). The application of the technique in biomedicine is illustrated by proton radiographs of botanical samples. (author)

  19. 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)

  20. Digital radiographic complexes for traumatological department

    International Nuclear Information System (INIS)

    Sudakevich, Y.; Kovalenko, V.; Miroshnichenko, S.; Balashov, S.; Nevgasimy, A.

    2013-01-01

    The paper deals with a budget digital X-ray equipment in operating trauma unit. The proposed set of equipment lets receive X-ray images of required quality at a significantly reduced requirements for radiation protection in the operating room, and to protect the personnel. We consider two variants of the equipment: for operating rooms in the traumatological department in the central district hospitals on the basis of portable X-ray unit and pediatric trauma unit on the basis of micro focus X-ray generator. (authors)

  1. 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

  2. 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.)

  3. Image enhancement of digital periapical radiographs according to diagnostic tasks

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jin Woo; Han, Won Jeong; Kim, Eun Kyung [Dept. of Oral and Maxillofacial Radiology, Dankook University College of Dentistry, Cheonan (Korea, Republic of)

    2014-03-15

    his study was performed to investigate the effect of image enhancement of periapical radiographs according to the diagnostic task. Eighty digital intraoral radiographs were obtained from patients and classified into four groups according to the diagnostic tasks of dental caries, periodontal diseases, periapical lesions, and endodontic files. All images were enhanced differently by using five processing techniques. Three radiologists blindly compared the subjective image quality of the original images and the processed images using a 5-point scale. There were significant differences between the image quality of the processed images and that of the original images (P<0.01) in all the diagnostic task groups. Processing techniques showed significantly different efficacy according to the diagnostic task (P<0.01). Image enhancement affects the image quality differently depending on the diagnostic task. And the use of optimal parameters is important for each diagnostic task.

  4. Image enhancement of digital periapical radiographs according to diagnostic tasks

    International Nuclear Information System (INIS)

    Choi, Jin Woo; Han, Won Jeong; Kim, Eun Kyung

    2014-01-01

    his study was performed to investigate the effect of image enhancement of periapical radiographs according to the diagnostic task. Eighty digital intraoral radiographs were obtained from patients and classified into four groups according to the diagnostic tasks of dental caries, periodontal diseases, periapical lesions, and endodontic files. All images were enhanced differently by using five processing techniques. Three radiologists blindly compared the subjective image quality of the original images and the processed images using a 5-point scale. There were significant differences between the image quality of the processed images and that of the original images (P<0.01) in all the diagnostic task groups. Processing techniques showed significantly different efficacy according to the diagnostic task (P<0.01). Image enhancement affects the image quality differently depending on the diagnostic task. And the use of optimal parameters is important for each diagnostic task.

  5. Comparison of film/screen and PCR digital lateral cervical spine radiographs

    International Nuclear Information System (INIS)

    Silver, D.I.; Kreipke, D.L.; Tarver, R.; Braunstein, E.M.

    1988-01-01

    The authors compared film/screen and Phillips computed radiography (PCR) radiographs of the cervical spine. In 109 patients. fiilm/screen and digital radiographs were compared for adequate visualization (readability) of bone, soft tissue, and trachea. The lowest cervical vertebra seen was noted in each case. The radiographs were interpreted by four radiologists, and both interobserver and intraobserver consistency were measured. Of the PCR radiographs, 97% were readable with a viewbox alone. Of the film/screen radiographs, 9% were readable with a viewbox. With a hotlight, 83% of the film/screen radiographs became readable. Bone, soft tissue, and trachea were better seen on PCR radiographs than on film/screen radiographs (P<.001). There was less interobserver variation on digital radiographs. Readability of cervical spine radiographs was significantly improved with PCR

  6. Digital radiographic scanning installation with multiwire proportional chamber

    International Nuclear Information System (INIS)

    Babichev, E.A.; Baru, S.E.; Khabakhpashev, A.G.; Kolachev, G.M.; Savinov, G.A.; Shekhtman, L.I.; Sidorov, V.A.; Volobuev, A.I.

    1991-01-01

    A digital radiographic installation for medical diagnostics is described. Distribution of X-ray intensity in horizontal direction is measured by a one-coordinate MWPC with a 1.2 mm channel. A two-dimensional image is produced by mechanical scanning with 1 mm channel width in vertical direction. The number of pixels in the image is 320x256. The MWPC works in count mode with quantum efficiency 25% (50 keV) and count rate capability 600 kHz/channel. Results of testing a prototype with 64 channels 0.6 mm width are also presented. (orig.)

  7. Qualification of a digital radiographic equipment for thin weld inspection

    International Nuclear Information System (INIS)

    Boulanger, G.; Furlan, J.

    1988-04-01

    The level of quality asked for welding plugs to fuel pins requires to test all the welds, that is to say about 200 000 welds of the fuel assemblies of the fast reactor Super-Phenix. X-ray radiography is one of the tests. Before the operation was done on a film by the personnel automatic selection of tested material and image processing are substituted to the film in the digital radiographic equipment IRENE. Main advantages are: elimination of human factor in defect appreciation, reliability of image processing and instant availability. On 1000 welds a good correlation is obtained between results on films and those of image processing [fr

  8. Acquired image quality in digital industrial radiographic equipments

    International Nuclear Information System (INIS)

    Oliveira, Cristiane de Queiroz; Lopes, Ricardo Tadeu; Oliveira, Davi F.

    2008-01-01

    The computerized radiographic application in the industrial area is a recent event. The imaging plate is the equipment used as imaging receiver during the exposition radiographic technique, which consists of a flexible photostimulable phosphor screen, capable of storing the photons energy of the incident X and γ rays and of a reading unit which uses a laser device to stimulate a visible light. As two types of phosphor screen are manufactured, one for general use (General Plate - GP) and another one for specific using (High Resolution-HR), one of the objectives of this study was to evaluate the spatial resolution capability in both plates using the Kodak equipment. Furthermore, equipment from different makers, Kodak and General Electric Company - GE, were compared. Two phosphor screen HR were used as the main objective of this study. Imaging Quality Indicators - IQI were used to evaluate the spatial resolution of the images in accordance with ASME and DIN standard. The results show that after evaluating the GP and HR Kodak plates, the HR plate was capable of showing a larger resolution of details. However, after evaluating the performance of the HR Kodak plate and GE plate, over the same acquisition condition and with the same size of the laser focal set of 87 μm, the results show a superiority in the GE equipment used for industrial radiographic, mainly for processed images in each specific ambient of digital processing and its performance in meeting satisfactorily the ASME code and the DIN standard. (author)

  9. Development of digital radiographic inspection method in MINT

    International Nuclear Information System (INIS)

    Mohd Ashhar Khalid; Abdul Razak Hamzah; Abdul Aziz Mohamad; Anuar Mikdad Muad; Nolida Yussup; Maslina Mohd Ibrahim

    2002-01-01

    Industrial radiography has been employed for the evaluation of defects, such as cracks, porosity and foreign inclusions found in casting and welds. It has become one of the major techniques in industrial non-destructive testing for the past 40 years. Although this technique has been well developed, further improvement can be implemented especially with the advancement of electronics and computer technology. Digital image processing techniques and application of artificial intelligence methods allow the interpretation of the image to be automated, avoiding the presence of human operators making the inspection system faster, more reliable and reproducible. Numerous works has been reported by various groups on the development of an automated, computer based evaluation algorithms. This paper reports the development and progress of digital radiographic inspection method in MINT. (Author)

  10. 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

  11. 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.

  12. 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.)

  13. Computerized detection of pneumothorax on digital chest radiographs

    International Nuclear Information System (INIS)

    Sanada, S.; Doi, K.; MacMahon, H.; Montner, S.M.

    1990-01-01

    This paper reports on neumothoraces that are clinically important abnormalities that usually appear as a subtle, fine line pattern on chest radiographs. We are developing a computer vision system for automated detection of pneumothorax to aid radiologists diagnosis. Chest images were digitized with a 0.175-mm pixel size, yielding a 2,000 x 2,430 matrix size, and 10 bits of gray scale. After indentification of the lung regions, an edge detection filter was employed in the apical areas to enhance a pneumothorax pattern. Ribs were detected with a technique based on statistical analysis of edge gradients and their orientations. Points located on a curved line suggestive of a pneumothorax in this enhanced image were detected with a Hough transform

  14. A portable software tool for computing digitally reconstructed radiographs

    International Nuclear Information System (INIS)

    Chaney, Edward L.; Thorn, Jesse S.; Tracton, Gregg; Cullip, Timothy; Rosenman, Julian G.; Tepper, Joel E.

    1995-01-01

    Purpose: To develop a portable software tool for fast computation of digitally reconstructed radiographs (DRR) with a friendly user interface and versatile image format and display options. To provide a means for interfacing with commercial and custom three-dimensional (3D) treatment planning systems. To make the tool freely available to the Radiation Oncology community. Methods and Materials: A computer program for computing DRRs was enhanced with new features and rewritten to increase computational efficiency. A graphical user interface was added to improve ease of data input and DRR display. Installer, programmer, and user manuals were written, and installation test data sets were developed. The code conforms to the specifications of the Cooperative Working Group (CWG) of the National Cancer Institute (NCI) Contract on Radiotherapy Treatment Planning Tools. Results: The interface allows the user to select DRR input data and image formats primarily by point-and-click mouse operations. Digitally reconstructed radiograph formats are predefined by configuration files that specify 19 calculation parameters. Enhancements include improved contrast resolution for visualizing surgical clips, an extended source model to simulate the penumbra region in a computed port film, and the ability to easily modify the CT numbers of objects contoured on the planning computed tomography (CT) scans. Conclusions: The DRR tool can be used with 3D planning systems that lack this functionality, or perhaps improve the quality and functionality of existing DRR software. The tool can be interfaced to 3D planning systems that run on most modern graphics workstations, and can also function as a stand-alone program

  15. 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.)

  16. The x-ray light valve: A potentially low-cost, digital radiographic imaging system-concept and implementation considerations

    International Nuclear Information System (INIS)

    Webster, Christie Ann; Koprinarov, Ivaylo; Germann, Stephen; Rowlands, J. A.

    2008-01-01

    New x-ray radiographic systems based on large-area flat-panel technology have revolutionized our capability to produce digital x-ray images. However, these imagers are extraordinarily expensive compared to the systems they are replacing. Hence, there is a need for a low-cost digital imaging system for general applications in radiology. A novel potentially low-cost radiographic imaging system based on established technologies is proposed--the X-Ray Light Valve (XLV). This is a potentially high-quality digital x-ray detector made of a photoconducting layer and a liquid-crystal cell, physically coupled in a sandwich structure. Upon exposure to x rays, charge is collected on the surface of the photoconductor. This causes a change in the optical properties of the liquid-crystal cell and a visible image is generated. Subsequently, it is digitized by a scanned optical imager. The image formation is based on controlled modulation of light from an external source. The operation and practical implementation of the XLV system are described. The potential performance of the complete system and issues related to sensitivity, spatial resolution, noise, and speed are discussed. The feasibility of clinical use of an XLV device based on amorphous selenium (a-Se) as the photoconductor and a reflective electrically controlled birefringence cell is analyzed. The results of our analysis indicate that the XLV can potentially be adapted to a wide variety of radiographic tasks

  17. Method of simulating dose reduction for digital radiographic systems

    International Nuclear Information System (INIS)

    Baath, M.; Haakansson, M.; Tingberg, A.; Maansson, L. G.

    2005-01-01

    The optimisation of image quality vs. radiation dose is an important task in medical imaging. To obtain maximum validity of the optimisation, it must be based on clinical images. Images at different dose levels can then either be obtained by collecting patient images at the different dose levels sought to investigate - including additional exposures and permission from an ethical committee - or by manipulating images to simulate different dose levels. The aim of the present work was to develop a method of simulating dose reduction for digital radiographic systems. The method uses information about the detective quantum efficiency and noise power spectrum at the original and simulated dose levels to create an image containing filtered noise. When added to the original image this results in an image with noise which, in terms of frequency content, agrees with the noise present in an image collected at the simulated dose level. To increase the validity, the method takes local dose variations in the original image into account. The method was tested on a computed radiography system and was shown to produce images with noise behaviour similar to that of images actually collected at the simulated dose levels. The method can, therefore, be used to modify an image collected at one dose level so that it simulates an image of the same object collected at any lower dose level. (authors)

  18. Radiographic assessment of proximal caries: A comparison between film-based and dexis digital imaging systems

    Directory of Open Access Journals (Sweden)

    Anupama N Kalappanavar

    2011-01-01

    Full Text Available This study compared Kodak Ektaspeed film and Dexis digital imaging systems for their diagnostic accuracy in detection of proximal canes in 210 proximal surfaces from 105 extracted human teeth (20 premolars and 85 molars, 129 of which were carious. Ground teeth were evaluated histologically. The images were assessed by an observer. ANOVA revealed that groups differ in scoring patterns with f-value of 26.72 and p < 0.01. The mean caries score by histologic assessment was significantly (p < 0.01 more when compared with the scores obtained by conventional and Dexis digital radiographic methods. The mean score for conventional radiographic method was slightly more than Dexis digital radiographic method, but the difference was statistically insignificant (p < 0.05. Both the radiographic methods were less accurate in detecting proximal canes confined to enamel, but as the lesion depth was increased to dentin, the rate of caries detection increased dramatically. It was concluded that both conventional and Dexis digital radiographic methods under estimated canes depth when compared with histologic method. Lastly, conventional film radiographs and Dexis digital radiographs did not perform significantly different from each other in the detection of canes.

  19. Digital image processing of periapical radiographs with low dose of radiation

    International Nuclear Information System (INIS)

    Kerbauy, Warley David; Moraes, Luiz Cesar de

    1996-01-01

    The aim of the study was to evaluate whether digitized images obtained from peri apical radiographs taken with low dose of radiation could be improved with the aid of a computer software (Photo Styler) for digital treatment. Serial and standardized radiographs of molar and pre molar areas were studied. A total of 57 images equivalent to the radiographs taken with reduced exposure time (60 and 80% of the time considered normal), digitized and treated, were submitted to the evaluation of seven examiners which compared them with those images without treatment. It was verified that about 80% of the images equivalent to the radiographs taken with 60% reduction of ordinary exposure time were considered to having quality for supporting diagnosis. As for the images taken with 80% reduction of ordinary exposure time, about 50% of them were considered suitable for the same purpose. (author)

  20. Conventional and digital radiographic methods in the detection of simulated external root resorptions: A comparative study

    Directory of Open Access Journals (Sweden)

    C J Sanjay

    2009-01-01

    Full Text Available Objective : To evaluate and compare the efficacy of conventional and digital radiographic methods in the detection of simulated external root resorption cavities and also to evaluate whether the detectability was influenced by resorption cavity sizes. Methods : Thirty-two selected teeth from human dentate mandibles were radiographed in orthoradial, mesioradial and distoradial aspect using conventional film (Insight Kodak F-speed; Eastman Kodak, Rochester, NY and a digital sensor (Trophy RVG advanced imaging system with 0.7mm and 1.0mm deep cavities prepared on their vestibular, mesial and distal surfaces at the cervical, middle and apical thirds. Three dental professionals, an endodontist, a radiologist and a general practitioner, evaluated the images twice with a one-week time interval. Results : No statistical significance was seen in the first observation for both conventional and digital radiographic methods in the detection of simulated external root resorptions and for small and medium cavities but statistical difference was noted in the second observation (P< 0.001 for both the methods. Conclusion : Considering the methodology and the overall results, conventional radiographic method (F-speed performed slightly better than the digital radiographic method in the detection of simulated radiographic method but better consistency was seen with the digital system. Overall size of the resorption cavity had no influence on the performance of both methods and suggests that initial external root resorption lesion is not well-appreciated with both the methods as compared to the advanced lesion.

  1. A study on assessment of the length of styloid process in digital panoramic radiographs

    Directory of Open Access Journals (Sweden)

    Nikita Gupta

    2015-01-01

    Full Text Available Introduction: The styloid process (SP is an anatomical structure whose clinical importance is not well understood. Aims and Objectives: This study aimed to study the type of SP as per Langlais′ classification and to assess the feasibility of digital panoramic radiographs in measuring the length of SP. Materials and Methods: Eighty digital panoramic radiographs of patients with dental problems were retrieved from archives of our department as soft copies. The radiographs were taken using a digital panoramic system. The radiographic length of SP was measured on both sides using measurement toolbars on accompanying analysis software. The type of elongation patterns of SP was classified as per Langlais′ classification. Finally, the data were subjected to statistical analysis. Results: The average length of the left and right side SPs was 29.1882 ± 6.86 and 28.16 ± 6.44, respectively. Majority of patients were found to be asymptomatic, and Langlais′ Type I elongated SP was more common than others. Conclusion: Digital panoramic radiographs are valuable tools in early detection of elongated SP. Digital radiographs help in avoiding a misdiagnosis of tonsillar pain or pain of dental, pharyngeal, or muscular region.

  2. Full-body digital radiographic imaging of the injured child

    African Journals Online (AJOL)

    radiographic exposure increasing the cumulative dose of ionising ... radiography system in the Trauma Unit at Red Cross War Memorial ..... that resveratrol and similar drugs will treat age-related disorders such as type 2 diabetes and cancer.

  3. Source-to-detector distance and beam center do not affect radiographic measurements of acetabular morphology

    International Nuclear Information System (INIS)

    Goldman, Ashton H.; Hoover, Kevin B.

    2017-01-01

    Multiple radiographic acquisition techniques have been evaluated for their effect on measurements of acetabular morphology. This cadaveric study examined the effect of two acquisition parameters not previously evaluated: beam center position and source-to-detector distance. This study also evaluated the effect of reader differences on measurements. Following calibration of measurements between two readers using five clinical radiographs (training), radiographs were obtained from two cadavers using four different source-to-detector distances and three different radiographic centers for a total of 12 radiographic techniques (experimental). Two physician readers acquired four types of measurements from each cadaver radiograph: lateral center edge angle, peak-to-edge distance, Sharp's angle, and the Tonnis angle. All measurements were evaluated for intra-class correlation coefficient (ICC), kappa statistics for hip dysplasia, and factors that resulted in measurement differences using a mixed statistical model. After training of the two physician readers, there was strong agreement in their hip morphology measurements (ICC 0.84-0.93), agreement in the presence of hip dysplasia (κ = 0.58-1.0), and no measurement difference between physician readers (p = 0.12-1.0). Experimental cadaver measurements showed moderate-to-strong agreement of the readers (ICC 0.74-0.93) and complete agreement on dysplasia (κ = 1). After accounting for reader and radiographic technique, there was no difference in hip morphology measurements (p = 0.83-0.99). In this cadaveric study, measurements of hip morphology were not affected by varying source-to-detector distance or beam center. We conclude that these acquisition parameters are not likely to affect the diagnosis of hip dysplasia in a clinical setting. (orig.)

  4. Source-to-detector distance and beam center do not affect radiographic measurements of acetabular morphology

    Energy Technology Data Exchange (ETDEWEB)

    Goldman, Ashton H. [Department of Orthopaedic Surgery, Virginia Commonwealth University, Richmond, VA (United States); Hoover, Kevin B. [Virginia Commonwealth University, Department of Radiology, 1250 E Marshall St. 3rd Floor, PO Box 980615, Richmond, VA (United States)

    2017-04-15

    Multiple radiographic acquisition techniques have been evaluated for their effect on measurements of acetabular morphology. This cadaveric study examined the effect of two acquisition parameters not previously evaluated: beam center position and source-to-detector distance. This study also evaluated the effect of reader differences on measurements. Following calibration of measurements between two readers using five clinical radiographs (training), radiographs were obtained from two cadavers using four different source-to-detector distances and three different radiographic centers for a total of 12 radiographic techniques (experimental). Two physician readers acquired four types of measurements from each cadaver radiograph: lateral center edge angle, peak-to-edge distance, Sharp's angle, and the Tonnis angle. All measurements were evaluated for intra-class correlation coefficient (ICC), kappa statistics for hip dysplasia, and factors that resulted in measurement differences using a mixed statistical model. After training of the two physician readers, there was strong agreement in their hip morphology measurements (ICC 0.84-0.93), agreement in the presence of hip dysplasia (κ = 0.58-1.0), and no measurement difference between physician readers (p = 0.12-1.0). Experimental cadaver measurements showed moderate-to-strong agreement of the readers (ICC 0.74-0.93) and complete agreement on dysplasia (κ = 1). After accounting for reader and radiographic technique, there was no difference in hip morphology measurements (p = 0.83-0.99). In this cadaveric study, measurements of hip morphology were not affected by varying source-to-detector distance or beam center. We conclude that these acquisition parameters are not likely to affect the diagnosis of hip dysplasia in a clinical setting. (orig.)

  5. Portable pulsed X-ray digital radiographic system based on network transmission

    International Nuclear Information System (INIS)

    Tang Le; Li Yuanjing; Wang Yi; Cheng Jianping

    2004-01-01

    Network communication technology of TCP/IP protocol serves as application in pulse X-ray digital radiography system. The system radiographs synchronously with pulse X-ray and converts image signals to digital data, which are transmitted to computer for displaying and processing in network. The system composing structures are present and portable and other characteristics are introduced. (authors)

  6. 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.

  7. 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

  8. 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.

  9. Review and evaluation of technology, equipment, codes and standards for digitization of industrial radiographic film

    International Nuclear Information System (INIS)

    1992-05-01

    This reports contains a review and evaluation of the technology, equipment, and codes and standards related to the digitization of industrial radiographic film. The report presents recommendations and equipment-performance specifications that will allow the digitization of radiographic film from nuclear power plant components in order to produce faithful reproductions of flaw images of interest on the films. Justification for the specifications selected are provided. Performance demonstration tests for the digitization process are required and criteria for such tests is presented. Also several comments related to implementation of the technology are presented and discussed

  10. Brazilian young dental practitioners' use and acceptance of digital radiographic examinations

    Energy Technology Data Exchange (ETDEWEB)

    Rovaris, Karla; De Faria Vasconcelos, Karla; Do Nascimento, Eduarda Helena Leandro; Oliveira, Matheus Lima; Freitas, Deborah Queiroz; Haiter-Neto, Francisco [Div. of Oral Radiology, Dept. of Oral Diagnosis, Piracicaba Dental School, University of Campinas (UNICAMP), Sao Paulo (Brazil)

    2016-12-15

    The aim of this study was to investigate the use and acceptance of digital radiographic examinations by Brazilian dental practitioners in daily practice and to evaluate the advances that have occurred over the past 5 years. Dental practitioners enrolled in extension courses at the Piracicaba Dental School, University of Campinas, Brazil, responded to a self-administered questionnaire in the years 2011 and 2015. They were asked about sociodemographic factors and their knowledge and use of digital radiographic examinations. Descriptive analysis was performed, as well as the chi-square and Fisher exact tests, with a significance level of 5% (α=0.05). A total of 181 participants responded to the questionnaire in the years 2011 and 2015. Most of the respondents worked in private practice, had graduated within the last 5 years, and were between 20 and 30 years old. In 2011, 55.6% of respondents reported having ever used digital radiographic examinations, while in 2015 this number increased significantly to 85.4% (p<.0001), out of which 71.4% preferred it to conventional images. Moreover, 21.4% of respondents reported having used digital radiographic examinations for more than 3 years. A significant increase in use of intraoral digital radiography (p=0.0316) was observed in 2015. In both years, image quality and high cost were indicated, respectively, as the main advantage and disadvantage of digital radiographic examinations. This study showed that digital radiology has become more common in Brazil over the past 5 years. Most of the Brazilian dental practitioners evaluated in 2015 used digital radiographic examinations.

  11. Brazilian young dental practitioners' use and acceptance of digital radiographic examinations

    International Nuclear Information System (INIS)

    Rovaris, Karla; De Faria Vasconcelos, Karla; Do Nascimento, Eduarda Helena Leandro; Oliveira, Matheus Lima; Freitas, Deborah Queiroz; Haiter-Neto, Francisco

    2016-01-01

    The aim of this study was to investigate the use and acceptance of digital radiographic examinations by Brazilian dental practitioners in daily practice and to evaluate the advances that have occurred over the past 5 years. Dental practitioners enrolled in extension courses at the Piracicaba Dental School, University of Campinas, Brazil, responded to a self-administered questionnaire in the years 2011 and 2015. They were asked about sociodemographic factors and their knowledge and use of digital radiographic examinations. Descriptive analysis was performed, as well as the chi-square and Fisher exact tests, with a significance level of 5% (α=0.05). A total of 181 participants responded to the questionnaire in the years 2011 and 2015. Most of the respondents worked in private practice, had graduated within the last 5 years, and were between 20 and 30 years old. In 2011, 55.6% of respondents reported having ever used digital radiographic examinations, while in 2015 this number increased significantly to 85.4% (p<.0001), out of which 71.4% preferred it to conventional images. Moreover, 21.4% of respondents reported having used digital radiographic examinations for more than 3 years. A significant increase in use of intraoral digital radiography (p=0.0316) was observed in 2015. In both years, image quality and high cost were indicated, respectively, as the main advantage and disadvantage of digital radiographic examinations. This study showed that digital radiology has become more common in Brazil over the past 5 years. Most of the Brazilian dental practitioners evaluated in 2015 used digital radiographic examinations

  12. Brazilian young dental practitioners' use and acceptance of digital radiographic examinations.

    Science.gov (United States)

    Rovaris, Karla; de Faria Vasconcelos, Karla; do Nascimento, Eduarda Helena Leandro; Oliveira, Matheus Lima; Freitas, Deborah Queiroz; Haiter-Neto, Francisco

    2016-12-01

    The aim of this study was to investigate the use and acceptance of digital radiographic examinations by Brazilian dental practitioners in daily practice and to evaluate the advances that have occurred over the past 5 years. Dental practitioners enrolled in extension courses at the Piracicaba Dental School, University of Campinas, Brazil, responded to a self-administered questionnaire in the years 2011 and 2015. They were asked about sociodemographic factors and their knowledge and use of digital radiographic examinations. Descriptive analysis was performed, as well as the chi-square and Fisher exact tests, with a significance level of 5% (α=0.05). A total of 181 participants responded to the questionnaire in the years 2011 and 2015. Most of the respondents worked in private practice, had graduated within the last 5 years, and were between 20 and 30 years old. In 2011, 55.6% of respondents reported having ever used digital radiographic examinations, while in 2015 this number increased significantly to 85.4% (p<.0001), out of which 71.4% preferred it to conventional images. Moreover, 21.4% of respondents reported having used digital radiographic examinations for more than 3 years. A significant increase in use of intraoral digital radiography (p=0.0316) was observed in 2015. In both years, image quality and high cost were indicated, respectively, as the main advantage and disadvantage of digital radiographic examinations. This study showed that digital radiology has become more common in Brazil over the past 5 years. Most of the Brazilian dental practitioners evaluated in 2015 used digital radiographic examinations.

  13. Evaluation of underexposed conventional radiographs after digitization. Auswertung fehlbelichteter konventioneller Roentgenaufnahmen nach Digitalisierung

    Energy Technology Data Exchange (ETDEWEB)

    Wenz, W. (Freiburg Univ. (Germany). Abt. Roentgendiagnostik); Buitrago-Tellez, C. (Freiburg Univ. (Germany). Abt. Roentgendiagnostik); Moenig, H. (Freiburg Univ. (Germany). Inst. fuer Biophysik und Strahlenbiologie); Niemeier, R. (Digital Diagnostik Deutschland GmbH, Freiburg im Breisgau (Germany))

    1993-02-01

    Inadequate exposure of analogue radiographs is reported in the literature to occur in 5-25% of cases. Therefore, the present study was performed to test whether selective image processing after digitization could reveal diagnostic details on underexposed radiographs. In addition, the minimal exposure values required for diagnostic purposes after adequate image processing were studied. Phantom studies, organ preparations and measurements of physical parameters with decreasing exposure values were performed. The detection of anatomic and pathologic (nondisplaced fracture lines, microcalcification and renal stones) structures were evaluated by 12 readers. Radiographs with exposure values 20-40% lower than 'ideal' values can provide adequate diagnostic images after digital processing. The diagnostic information is significantly impaired with values under 50% of the correct exposure values. In conclusion, this method is adequate to save underexposed radiographs for diagnostic purposes and to avoid repeated examinations. (orig.)

  14. 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.

  15. Neutron radiographic characteristics of MA-ND type (allyl-diglycol-carbonate) nuclear track detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ilic, R.; Rant, J.; Humar, M.; Somogyi, G.; Hunyadi, I.

    1986-01-01

    Neutron radiographic properties of recently developed new nuclear track detectors (MA-ND/..cap alpha.., MA-ND/p and MA-ND/p1), manufactured from allyl diglycol carbonate, were studied. It was found that the quality of radiographic image has an optimum at a removed layer thickness of about 0.8 ..mu..m. The image obtained under this condition is characterized by high detection sensitivity to neutrons (approx. 8.10/sup -3/ tracks/nsub(th) when using B converter) and by excellent inherent unsharpness (approx. 5 ..mu..m) as well as high image contrast (maximum value of net optical density is approx. 1.4).

  16. Single exposure simultaneous acquisition of digital and conventional radiographs utilizing unaltered dose

    International Nuclear Information System (INIS)

    Oestmann, J.W.; Greene, R.

    1988-01-01

    We describe the simultaneous acquisition of digital and conventional radiographs with a single standard radiographic exposure. A digitizable storage phosphor (ST Imaging Plate, Fuji) is sandwiched into a radiographic cassette (X-Omatic, Kodak) behind a conventional radiographic film-screen combination (Lanex medium screens, OC film, Kodak). The barium fluorohalide storage phosphor is digitized with a helium-neon laser scanner (TCR 201, Toshiba), and the conventional radiograph is processed in the standard fashion (M7B, Kodak). The storage phosphor is exposed by the 'wasted' radiation normally exiting the back of the film-screen combination (32% of the cassette entrance dose at 141 kVp). At a standard exposure (6.3 mAs), the conventional radiograph is of unaltered quality, and the digital image appears to have an adequate signal-to-noise ratio for chest studies despite the lower exposure dose. This technique produces twin images of identical spatial and temporal registration and avoids the added radiation exposure normally required to carry out comparative studies. (orig.)

  17. Diagnostic ability of the periapical radiographs and digital image in the detection of the artificial proximal caries

    International Nuclear Information System (INIS)

    Heo, Min Suk; You, Dong Soo

    1994-01-01

    Recently, the digital image was introduced into radiological image. The digital image has the power of contrast enhancement, histogram control, and other digitally enhancement. At the point of the resolution, periapical radiograph is superior to the digital image, but enhanced digital procedure improves the diagnostic ability of the digital image. The purpose of this study was to evaluate the diagnostic ability of artificial proximal caries in conventional radiographs, digital radiographs and enhanced digital radiographs (histogram specification). ROC (Receiver Operating Characteristic) analysis and paired t-test were used for the evaluation of detectability, and following results were acquired: 1. The mean ROC area of conventional radiographs was 0.9274. 2. The mean ROC area of unenhanced digital image was 0.9168. 3. The mean ROC area of enhanced digital image was 0.9339. 4. The diagnostic ability of three imaging methods was not significant difference (p>0.05). So, the digital images had similar diagnostic ability of artificial proximal caries to conventional radiographs. If properly enhanced digital image, it may be superior to conventional radiographs.

  18. A radiographic image archive system on digital optical disks

    International Nuclear Information System (INIS)

    Mankovich, N.J.; Taira, R.K.; Cho, P.S.; Wong, W.K.; Stewart, B.K.; Huang, H.K.

    1986-01-01

    The recent introduction of projection computed radiography (CR) systems allows radiology departments to consider digital operation in over 90% of performed procedures. Ideally, current patient procedures from CT, CT, and MR along with laser-digitized historical films should be centrally stored at their full digital resolution. Magnetic disks, because of their limited storage capacity and expense, can only retain these data on a limited basis. The author devised an optical disk archive system which automatically stores images directly onto 2.6-gigabyte optical cartridges without recourse to film. This system is in full clinical operation in the UCLA Pediatric Radiology Section of the authors' department. From this experience they present (a) an analysis of the digital archiving requirements of the Pediatric Radiology Section based on CR, CT, MR, and laser digitized films; (b) the archive and retrieval methods along with performance statistics; and (c) the procedure for assuring digital image integrity

  19. 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)

  20. Computerized detection of lung nodules in digital chest radiographs

    International Nuclear Information System (INIS)

    Giger, M.L.; Doi, K.; MacMahon, H.

    1987-01-01

    Detection of cancerous lung nodules in chest radiographs is one of the more important tasks performed by a radiologist. In addition, the ''miss rate'' associated with the radiographic detection of lung nodules is approximately 30%. A computerized scheme that alerts the radiologist to possible locations of lung nodules should allow this number of false-negative diagnoses to be reduced. The authors are developing a computer-aided nodule detection scheme based on a difference image approach. They attempt to eliminate the camouflaging background structure of the normal lung anatomy by creating, from a single-projection chest image, two images: one in which the signal-to-noise ratio (SNR) of the nodule is maximized and another in which that SNR is suppressed while the processed background remains essentially the same. Thus, the difference between these two processed images should consist of the nodule superimposed on a relatively uniform background in which the detection task may be simplified. This difference image approach is fundamentally different from conventional subtraction techniques (e.g., temporal or dual-energy subtraction) in that the two images which are subtracted arise from the same single-projection chest radiograph. Once the difference image is obtained, thresholding is performed along with tests for circularity, size and growth in order to extract the nodules. It should be noted that once an original chest image is input to the computer the nodule detection process is totally automated

  1. Digitizing pediatric chest radiographs: comparison of low-cost, commercial off-the-shelf technologies

    International Nuclear Information System (INIS)

    Ruess, L.; Shiels, K.C.; Cho, K.H.; O'Connor, S.C.; Uyehara, C.F.T.; Person, D.A.; Whitton, R.K.

    2001-01-01

    Objective: To compare low-cost, off-the-shelf technology for digitizing pediatric chest radiographs. Materials and methods: Forty pediatric chest radiographs (hard copy), each with a single abnormality, were digitized using a commercial film digitizer and two low-cost methods: a digital camera and a flatbed scanner. A stratified, randomized, block design was used where 20 readers evaluated 40 different images to determine the ability to accurately detect the abnormality. Readers then rated all 160 images (40 images x 4 methods) for conspicuity of the abnormality and overall image quality. Results: Abnormalities were correctly identified on 82.3 % of hard copy images, 82.9 % of flatbed scanner images, 74.3 % of film digitizer images, and 69.7 % of digital camera images (p flatbed scanner > film digitizer > digital camera images. Conclusion: A low-cost flatbed scanner yielded digital pediatric chest images which were significantly superior to digital camera images While flatbed scanner images were interpreted with the equivalent diagnostic accuracy of hard copy images, they were rated lower for image quality and lesion conspicuity. (orig.)

  2. Panoramic images of conventional radiographs: digital panoramic dynamic images

    International Nuclear Information System (INIS)

    Schultze, M.

    2001-01-01

    The benefits of digital technic s to od ontology are evident. Instant images, the possibility to handle them, the reduction of exposition time to radiations, better quality image, better quality information, Stocking them in a compact disc, occupying very little space, allows an easy transport and duplication, as well as the possibility to transfer and save it in an electronica l support.This kind of communication allows the transmission of digital images and every other type of data, instantaneously and no matter distances or geographical borders. Anyway, we should point out that conventional and digital technic s reveal the same information contents

  3. 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)

  4. 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)

  5. The radiographic anatomy of the normal ovine digit, the metacarpophalangeal and metatarsophalangeal joints.

    Science.gov (United States)

    Duncan, Jennifer S; Singer, Ellen R; Devaney, Jane; Oultram, Joanne W H; Walby, Anna J; Lester, Bridie R; Williams, Helen J

    2013-03-01

    The aim of this project was to develop a detailed, accessible set of reference images of the normal radiographic anatomy of the ovine digit up to and including the metacarpo/metatatarsophalangeal joints. The lower front and hind limbs of 5 Lleyn ewes were radiographed using portable radiography equipment, a digital image processer and standard projections. Twenty images, illustrating the normal radiographic anatomy of the limb were selected, labelled and presented along with a detailed description and corresponding images of the bony skeleton. These images are aimed to be of assistance to veterinary surgeons, veterinary students and veterinary researchers by enabling understanding of the normal anatomy of the ovine lower limb, and allowing comparison with the abnormal.

  6. Mandibular ramus: A predictor for sex determination - A digital radiographic study

    Directory of Open Access Journals (Sweden)

    Kotya Naik Maloth

    2017-01-01

    Full Text Available Aim: To evaluate mandibular ramus linear measurements on digital panoramic radiographs and to assess the usefulness of mandibular ramus in sex determination. Material and Methods: A retrospective study was conducted on 100 patients (50 males and 50 females using digital panoramic radiographs of Khammam population with age ranging from 20 to 50 years. Standard digital panoramic radiographs were taken without any errors by Sirona, ORTHOPHOS XG 5 machine. The following five mandibular linear measurements were performed in cm such as upper ramus breadth, lower ramus breadth, condylar ramus height, projective ramus height, and coronoid ramus height. The obtained data were analyzed with the software SPSS 13.0 for statistical analysis using discriminate methods. Results: In the present study, all the linear measurements of mandibular ramus on digital panoramic radiographs showed a statistically significant difference between the genders. Conclusion: We conclude that the use of mandibular ramus is recommended as an aid for sex determination in forensic science due to their unique feature of sexual dimorphism.

  7. Development of a fully automated adaptive unsharp masking technique in digital chest radiograph

    International Nuclear Information System (INIS)

    Abe, Katsumi; Katsuragawa, Shigehiko; Sasaki, Yasuo

    1991-01-01

    We are developing a fully automated adaptive unsharp masking technique with various parameters depending on regional image features of a digital chest radiograph. A chest radiograph includes various regions such as lung fields, retrocardiac area and spine in which their texture patterns and optical densities are extremely different. Therefore, it is necessary to enhance image contrast of each region by each optimum parameter. First, we investigated optimum weighting factors and mask sizes of unsharp masking technique in a digital chest radiograph. Then, a chest radiograph is automatically divided into three segments, one for the lung field, one for the retrocardiac area, and one for the spine, by using histogram analysis of pixel values. Finally, high frequency components of the lung field and retrocardiac area are selectively enhanced with a small mask size and mild weighting factors which are previously determined as optimum parameters. In addition, low frequency components of the spine are enhanced with a large mask size and adequate weighting factors. This processed image shows excellent depiction of the lung field, retrocardiac area and spine simultaneously with optimum contrast. Our image processing technique may be useful for diagnosis of chest radiographs. (author)

  8. Digital training platform for interpreting radiographic images of the chest.

    Science.gov (United States)

    McLaughlin, L; Woznitza, N; Cairns, A; McFadden, S L; Bond, R; Hughes, C M; Elsayed, A; Finlay, D; McConnell, J

    2018-05-01

    Time delays and errors exist which lead to delays in patient care and misdiagnosis. Reporting clinicians follow guidance to form their own search strategy. However, little research has tested these training guides. With the use of eye tracking technology and expert input we developed a digital training platform to be used in chest image interpretation learning. Two sections of a digital training platform were planned and developed; A) a search strategy training tool to assist reporters during their interpretation of images, and B) an educational tool to communicate the search strategies of expert viewers to trainees by using eye tracking technology. A digital training platform for use in chest image interpretation was created based on evidence within the literature, expert input and two search strategies previously used in clinical practice. Images and diagrams, aiding translation of the platform content, were incorporated where possible. The platform is structured to allow the chest image interpretation process to be clear, concise and methodical. A search strategy was incorporated within the tool to investigate its use, with the possibility that it could be recommended as an evidence based approach for use by reporting clinicians. Eye tracking, a checklist and voice recordings have been combined to form a multi-dimensional learning tool, which has never been used in chest image interpretation learning before. The training platform for use in chest image interpretation learning has been designed, created and digitised. Future work will establish the efficacy of the developed approaches. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

  9. 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.

  10. Detection of proximal caries using digital radiographic systems with different resolutions.

    Science.gov (United States)

    Nikneshan, Sima; Abbas, Fatemeh Mashhadi; Sabbagh, Sedigheh

    2015-01-01

    Dental radiography is an important tool for detection of caries and digital radiography is the latest advancement in this regard. Spatial resolution is a characteristic of digital receptors used for describing the quality of images. This study was aimed to compare the diagnostic accuracy of two digital radiographic systems with three different resolutions for detection of noncavitated proximal caries. Diagnostic accuracy. Seventy premolar teeth were mounted in 14 gypsum blocks. Digora; Optime and RVG Access were used for obtaining digital radiographs. Six observers evaluated the proximal surfaces in radiographs for each resolution in order to determine the depth of caries based on a 4-point scale. The teeth were then histologically sectioned, and the results of histologic analysis were considered as the gold standard. Data were entered using SPSS version 18 software and the Kruskal-Wallis test was used for data analysis. P detection of proximal caries (P > 0.05). RVG access system had the highest specificity (87.7%) and Digora; Optime at high resolution had the lowest specificity (84.2%). Furthermore, Digora; Optime had higher sensitivity for detection of caries exceeding outer half of enamel. Judgment of oral radiologists for detection of the depth of caries had higher reliability than that of restorative dentistry specialists. The three resolutions of Digora; Optime and RVG access had similar accuracy in detection of noncavitated proximal caries.

  11. Gamma flaw detectors for radiographic control of welded joint quality under mounting conditions

    International Nuclear Information System (INIS)

    Khoroshev, V.N.; Galash, T.F.; Andreev, V.L.; Grigor'ev, V.M.; Medvedev, N.E.

    1978-01-01

    Main characteristics are presented of gamma flaw detector models used for radiographic control of the quality of welded steel and pipeline joints during assembly. Specially developed experimental models, operating with 75 Se, 90 Sr, 170 Tm, 137 Cs and 192 Ir sources are considered. The new instruments have been made on a single structural base, which creates a foundation for standardizing individual units of radiation heads, manual control panels, containers, exterior packings, devices and accessories, maintenance techniques, and repair techniques. They are distinguished by small sizes and weight, possibility of using a set of radiation sources ensuring control of 3-40 mm thick joints, and reliable protection. Special devices permit to reduce 2-3-folds the time needed for installing and orienting the flaw detectors. The expected economic effect from implementation of the new gamma flaw detectors into industry will amount to 1.5-10.0 thousand roubles per annum for one detector at approximate cost of each detector equal to 3.5-6.0 thousand roubles

  12. Relationship between image plates physical structure and quality of digital radiographic images in weld inspections

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Davi F.; Silva, Aline S.S.; Machado, Alessandra S.; Gomes, Celio S.; Nascimento, Joseilson; Lopes, Ricardo T., E-mail: davi@lin.ufrj.br.br, E-mail: aline@lin.ufrj.br, E-mail: celio@lin.ufrj.br, E-mail: alemachado@lin.ufrj.br, E-mail: joseilson@lin.ufrj.br, E-mail: ricardo@lin.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Instrumentacao Nuclear

    2015-07-01

    In the last decades a new type of detector which is based on photostimulable luminescence was developed. There are currently many kinds of image plates (IPs) available on the market, originating from different manufacturers. Each kind of plate distinguishes itself from the others by its peculiar physical structure and composition, two factors which have a direct influence upon the quality of the digital radiographic images obtained through them. For this study, several kinds of IPs were tested in order to determine in which way such influence takes place. For this purpose, each kind of IP has been characterized and correlated to its response in the final image. The aim of this work was to evaluate procedures for employing Computed Radiography (CR) to welding inspections in laboratory conditions using the Simple Wall Simple Image Technique (SWSI). Tests were performed in steel welded joins of thickness 5.33, 12.70 and 25.40 mm, using CR scanner and IPs available on the market. It was used an X-Ray equipment as radiation source. The image quality parameters Basic Spatial Resolution (BSR), Normalized Signal-to-Noise Ratio (SNR{sub N}), contrast and detectability were evaluated. In order to determine in which way the IPs' properties are correlated to its response in the final image, the thickness of the sensitive layer was determined and the grain size and the elemental composition of this layer were evaluated. Based on the results drawn from this study, it is possible to conclude that the physical characteristics of image plates are essential for determining the quality of the digital radiography images acquired with them. Regarding the chemical composition of the plates, it was possible to determine that, apart from the chemical elements that were expected to be found (Ba, I and Br), only two plates, with high resolution, do not have fluorine in their composition; the presence of Strontium was also detected in the chemical composition of the plates supplied by a

  13. Relationship between image plates physical structure and quality of digital radiographic images in weld inspections

    International Nuclear Information System (INIS)

    Oliveira, Davi F.; Silva, Aline S.S.; Machado, Alessandra S.; Gomes, Celio S.; Nascimento, Joseilson; Lopes, Ricardo T.

    2015-01-01

    In the last decades a new type of detector which is based on photostimulable luminescence was developed. There are currently many kinds of image plates (IPs) available on the market, originating from different manufacturers. Each kind of plate distinguishes itself from the others by its peculiar physical structure and composition, two factors which have a direct influence upon the quality of the digital radiographic images obtained through them. For this study, several kinds of IPs were tested in order to determine in which way such influence takes place. For this purpose, each kind of IP has been characterized and correlated to its response in the final image. The aim of this work was to evaluate procedures for employing Computed Radiography (CR) to welding inspections in laboratory conditions using the Simple Wall Simple Image Technique (SWSI). Tests were performed in steel welded joins of thickness 5.33, 12.70 and 25.40 mm, using CR scanner and IPs available on the market. It was used an X-Ray equipment as radiation source. The image quality parameters Basic Spatial Resolution (BSR), Normalized Signal-to-Noise Ratio (SNR N ), contrast and detectability were evaluated. In order to determine in which way the IPs' properties are correlated to its response in the final image, the thickness of the sensitive layer was determined and the grain size and the elemental composition of this layer were evaluated. Based on the results drawn from this study, it is possible to conclude that the physical characteristics of image plates are essential for determining the quality of the digital radiography images acquired with them. Regarding the chemical composition of the plates, it was possible to determine that, apart from the chemical elements that were expected to be found (Ba, I and Br), only two plates, with high resolution, do not have fluorine in their composition; the presence of Strontium was also detected in the chemical composition of the plates supplied by a

  14. Relationship between image plates physical structure and quality of digital radiographic images in weld inspections

    International Nuclear Information System (INIS)

    Ferreira de Oliveira, Davi; Silva, Aline S.S.; Machado, Alessandra S.; Gomes, Celio S.; Nascimento, Joseilson R.; Lopes, Ricardo T.

    2016-01-01

    In the last decades a new type of detector which is based on photostimulable luminescence was developed. There are currently many kinds of image plates (IPs) available on the market, originating from different manufacturers. Each kind of plate distinguishes itself from the others by its peculiar physical structure and composition, two factors which have a direct influence upon the quality of the digital radiographic images obtained through them. For this study, several kinds of IPs were tested in order to determine in which way such influence takes place. For this purpose, each kind of IP has been characterized and correlated to its response in the final image. The aim of this work was to evaluated procedures for employing Computed Radiography (CR) to welding inspections in laboratory conditions using the Simple Wall Simple Image Technique (SWSI). CR tests were performed in steel welded joins of thickness 5.33, 12.70 and 25.40 mm. It was used an X-Ray equipment as radiation source. The image quality parameters Basic Spatial Resolution (BSR), Normalized Signal-to-Noise Ratio (SNRN), contrast and detectability were evaluated. In order to determine in which way the IPs' properties are correlated to its response in the final image, the thickness of the sensitive layer was determined and the grain size and the elemental composition of this layer were evaluated. Based on the results drawn from this study, it is possible to conclude that the physical characteristics of IPs are essential for determining the quality of the digital radiography images acquired with them. Regarding the grain size and the thickness of the IPs' sensitive layers, we could determine that the dimensions of such parameters were smaller on the plates presenting higher BSR, SNRN and contrast. However, the image plates which produced images with the highest resolution have also proven to be the least sensitive ones. All these parameters have a direct influence in the detectability of the

  15. Computerized digital image processing on radiographs of canine filariosis

    International Nuclear Information System (INIS)

    Miyatake, K.; Okamoto, Y.; Minami, S.

    1999-01-01

    For objective evaluation in the lung arterial lesions, density histogram revealed by survey thoracic radiographies of fifteen canine filariosis and five normal canine were digitally analyzed, and preparation of pulmonary artery angiogram with inflated-fixed lung, the changes in the histogram and the pulmonary arterial lesion by a soft X-ray examination were compared. In the lung areas affected by filariosis, the density histogram increased the white level and decreased the black level in each part compared to a normal lung. In comparison with the normal parameters, those of the filariosis it were significantly increased in minimum grey level values (Min), maximum grey level values (Max), and the maximum frequency grey level values (Mode) and, it was significantly decreased in maximum frequency values (MaF). The pulmonary arterial lesion of the filariosis showed obvious morphological changes such as in distinction, pruning, angiectasis, and meandering. In the grade of pulmonary arterial lesion, the parameter Min, Max, Mode and MaF were changed significantly. From these results, it was clear that the methods for the lung arterial lesions analysis of X-ray images were confirmed to be highly beneficial in the lung arterial lesions for objective diagnosis

  16. [Conventional radiology, digital radiology with photostimulable phosphor, laser digitalization of thoracic radiographic films at the bedside. A comparative study].

    Science.gov (United States)

    Miceli, M; Stamati, R; Burci, P; Guidarelli, G; Sartoni Galloni, S

    1992-10-01

    The bedside chest images obtained with conventional radiology and with "on line" and "off line" digital modalities were compared to evaluate the respective capabilities in visualizing chest anatomical structures. Seventy patients were submitted to bedside chest examinations with a portable unit; both a conventional film and a digital system (PCR Graphics 1, Philips) with photostimulable phosphor imaging plate were fitted in the radiographic cassette. The former was digitized using an "off line" laser beam unit (FD 2000, Dupont); the latter was subsequently postprocessed by modifying contrast, optical density and spatial frequencies. Thus, 4 different viewing modalities were obtained for each examination: a) conventional radiography; b) standard digital radiography; c) postprocessed digital radiography; d) digitized conventional radiography. Detectability rates of chest anatomical structures were analyzed by 4 independent radiologists on the different images and expressed by a score 1-4. The values were always higher with digital modalities than with the conventional one and the differences were statistically significant (Student's t-test modified by Bonferroni). In particular, the greatest difference was found between c) and a) in retrocardiac lung parenchyma and in skeletal structures, in favour of c). Concerning the comparative adequacy of the various digital modalities, higher detectability rates of chest anatomical structures were obtained with c), but also with b), than with d).

  17. Ultra-high-resolution photoelectronic digital radiographic imaging system for medicine

    International Nuclear Information System (INIS)

    Bamford, B.R.; Nudelman, S.; Quimette, D.R.; Ovitt, T.W.; Reisken, A.B.; Spackman, T.J.; Zaccheo, T.S.

    1989-01-01

    The authors report the development of a new type of digital radiographic imaging system for medicine. Unlike previous digital radiographic systems that could not match the spatial resolution of film-screen systems, this system has higher spatial resolution and wider dynamic range than film-screen-based systems. There are three components to the system: a microfocal spot x-ray tube, a camera consisting of a Tektronix TK-2048M 2048 x 2048 CCD image sensor in direct contact with a Kodak Min-R intensifying screen, and a Gould IP-9000 with 2048 x 2048 processing and display capabilities. The CCD image sensor is a large-area integrated circuit and is 55.3 mm x 55.3 mm. It has a linear dynamic range of 12 bits or 4,096 gray levels

  18. Radiopacity evaluation of Portland and MTA-based cements by digital radiographic system.

    Science.gov (United States)

    Borges, Alvaro Henrique; Pedro, Fabio Luiz Miranda; Semanoff-Segundo, Alex; Miranda, Carlos Eduardo Saraiva; Pécora, Jesus Djalma; Cruz Filho, Antônio Miranda

    2011-01-01

    The aim of the present study was to evaluate the radiopacity of Portland and MTA-based cements using the Digora TM digital radiographic system. The performed tests followed specification number 57 from the American National Standard Institute/American Dental Association (2000) for endodontic sealing materials. The materials were placed in 5 acrylic plates, especially designed for this experiment, along with a graduated aluminum stepwedge varying from 1 to 10 mm in thickness. The set was radiographed at a 30 cm focus-object distance and with 0.2 s exposure time. After the radiographs were taken, the optical laser readings of radiographs were performed by Digora TM system. Five radiographic density readings were performed for each studied material and for each step of the aluminum scale. White ProRoot MTA (155.99±8.04), gray ProRoot MTA (155.96±16.30) and MTA BIO (143.13±16.94) presented higher radiopacity values (pPortland (119.76±22.34), gray Portland (109.71±4.90) and white structural Portland (99.59±12.88) presented lower radiopacity values (pcements were the only materials presenting radiopacity within the ANSI/ADA specifications.

  19. 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

  20. 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)

  1. Reproducibility of lateral cephalometric landmarks on conventional radiographs and spatial frequency-processed digital images

    International Nuclear Information System (INIS)

    Shin, Jeong Won; Heo, Min Suk; Lee, Sam Sun; Choi, Hyun Bae; Choi, Soon Chul; Choi, Hang Moon

    2002-01-01

    Computed radiography (CR) has been used in cephalometric radiography and many studies have been carried out to improve image quality using various digital enhancement and filtering techniques. During CR image acquisition, the frequency rank and type affect to the image quality. The aim of this study was to compare the diagnostic quality of conventional cephalometric radiographs to those of computed radiography. The diagnostic quality of conventional cephalometric radiographs (M0) and their digital image counterparts were compared, and at the same time, six modalities (M1-M6) of spatial frequency-processed digital images were compared by evaluating the reproducibility of 23 cephalometric landmark locations. Reproducibility was defined as an observer's deviation (in mm) from the mean between all observers. In comparison with the conventional cephalometric radiograph (M0), M1 showed statistically significant differences in 8 locations, M2 in 9, M3 12, M4 in 7, M5 in 12, and M6 showed significant differences in 14 of 23 landmark locations (p<0.05). The number of reproducible landmarks that each modality possesses were 7 in M6, 6 in M5, 5 in M3, 4 in M4, 3 in M2, 2 in M1, and 1 location in M0. The image modality that observers selected as having the best image quality was M5.

  2. Comparison of JPEG and wavelet compression on intraoral digital radiographic images

    International Nuclear Information System (INIS)

    Kim, Eun Kyung

    2004-01-01

    To determine the proper image compression method and ratio without image quality degradation in intraoral digital radiographic images, comparing the discrete cosine transform (DCT)-based JPEG with the wavelet-based JPEG 2000 algorithm. Thirty extracted sound teeth and thirty extracted teeth with occlusal caries were used for this study. Twenty plaster blocks were made with three teeth each. They were radiographically exposed using CDR sensors (Schick Inc., Long Island, USA). Digital images were compressed to JPEG format, using Adobe Photoshop v. 7.0 and JPEG 2000 format using Jasper program with compression ratios of 5 : 1, 9 : 1, 14 : 1, 28 : 1 each. To evaluate the lesion detectability, receiver operating characteristic (ROC) analysis was performed by the three oral and maxillofacial radiologists. To evaluate the image quality, all the compressed images were assessed subjectively using 5 grades, in comparison to the original uncompressed images. Compressed images up to compression ratio of 14: 1 in JPEG and 28 : 1 in JPEG 2000 showed nearly the same the lesion detectability as the original images. In the subjective assessment of image quality, images up to compression ratio of 9 : 1 in JPEG and 14 : 1 in JPEG 2000 showed minute mean paired differences from the original images. The results showed that the clinically acceptable compression ratios were up to 9 : 1 for JPEG and 14 : 1 for JPEG 2000. The wavelet-based JPEG 2000 is a better compression method, comparing to DCT-based JPEG for intraoral digital radiographic images.

  3. 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...

  4. 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

  5. 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

  6. Analysis of painted arts by energy sensitive radiographic techniques with the Pixel Detector Timepix

    Czech Academy of Sciences Publication Activity Database

    Žemlička, J.; Jakůbek, J.; Kroupa, M.; Hradil, David; Hradilová, J.; Mislerová, H.

    2011-01-01

    Roč. 6, - (2011), C01066/1-C01066/7 ISSN 1748-0221 R&D Projects: GA MŠk(CZ) LC06041 Institutional research plan: CEZ:AV0Z40320502 Keywords : inspection with x-rays * pixelated detectors and associated VLSI electronics * X-ray fluorescence (XRF) systems * X-ray radiography and digital radiography (DR) Subject RIV: CA - Inorganic Chemistry Impact factor: 1.869, year: 2011

  7. 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

  8. 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

  9. Prevalence of carotid and pulp calcifications: a correlation using digital panoramic radiographs

    International Nuclear Information System (INIS)

    Clark, Stephen J.; Scheetz, James P.; Khan, Zafrulla; Farman, Allan G.; Horsley, Scott H.; Beckstrom, Brice

    2009-01-01

    To compare the prevalence of pulp calcification with that of carotid calcification using digital panoramic dental radiographs. Digital panoramic radiographs of patients at a dental oncology clinic were included if (1) the carotid artery bifurcation region was visible bilaterally and (2) the patient had non-restored or minimally restored molars and/or canines. An endodontist evaluated the images for pulpal calcifications in the selected teeth. An oral and maxillofacial radiologist independently evaluated the same images for calcifications in the carotid bifurcation region. Odds-ratio and Pearson χ 2 were used for data analysis. Presence of pulpal calcification was also evaluated as a screening test for the presence of carotid calcification. A total of 247 panoramic radiographs were evaluated. 32% (n=80) had pulpal calcifications and 25% (n=61) had carotid calcifications with 12% (n=29) having both carotid and pulp calcifications. A significantly higher prevalence of both pulp and carotid calcification was found in subjects older than age 60 years compared to younger age groups. Accuracy of pulpal calcification in screening for carotid calcification was 66.4%. Both pulp and carotid calcifications were more prevalent in older individuals. The presence of pulp calcification was not a strong predictor for the presence of carotid calcification. (orig.)

  10. Prevalence of carotid and pulp calcifications: a correlation using digital panoramic radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Stephen J. [School of Dentistry, University of Louisville, Department of Periodontics, Endodontics and Dental Hygiene, Louisville, KY (United States); Scheetz, James P.; Khan, Zafrulla [University of Louisville, Department of Diagnostic Sciences, Prosthodontics and Restorative Dentistry, School of Dentistry, Louisville, KY (United States); Farman, Allan G. [School of Dentistry, University of Louisville, Department of Periodontics, Endodontics and Dental Hygiene, Louisville, KY (United States); Horsley, Scott H.; Beckstrom, Brice

    2009-03-15

    To compare the prevalence of pulp calcification with that of carotid calcification using digital panoramic dental radiographs. Digital panoramic radiographs of patients at a dental oncology clinic were included if (1) the carotid artery bifurcation region was visible bilaterally and (2) the patient had non-restored or minimally restored molars and/or canines. An endodontist evaluated the images for pulpal calcifications in the selected teeth. An oral and maxillofacial radiologist independently evaluated the same images for calcifications in the carotid bifurcation region. Odds-ratio and Pearson {chi}{sup 2} were used for data analysis. Presence of pulpal calcification was also evaluated as a screening test for the presence of carotid calcification. A total of 247 panoramic radiographs were evaluated. 32% (n=80) had pulpal calcifications and 25% (n=61) had carotid calcifications with 12% (n=29) having both carotid and pulp calcifications. A significantly higher prevalence of both pulp and carotid calcification was found in subjects older than age 60 years compared to younger age groups. Accuracy of pulpal calcification in screening for carotid calcification was 66.4%. Both pulp and carotid calcifications were more prevalent in older individuals. The presence of pulp calcification was not a strong predictor for the presence of carotid calcification. (orig.)

  11. Evaluation of the radiopacities of four different root canal sealers by digital radiographic technique

    Directory of Open Access Journals (Sweden)

    Özgür Özdemir

    2016-05-01

    Full Text Available OBJECTIVE: The aim of this study was to compare the radiopacities of four different root canal sealers and gutta-percha. MATERIALS AND METHOD: AH Plus, iRootSP, MTA Fillapex and Sealapex as root canal sealers and gutta-percha cones were tested. Standardized discs of the root canal sealers and the gutta-percha were prepared. Digital radiographs of the discs and an aluminum penetrometer were obtained by using a phosphor plate. The radiographic density of the sealers and the gutta-percha were measured by using the digital radiographic system’s own measurement tool, and equivalent aluminum thicknesses were determined by using an image editing software. Differences among radiopacities of the root canal sealers and the gutta-percha were analyzed using One-way ANOVA and Tukey post-hoc tests. RESULTS: Aluminum thickness equivalents of the radiopacity values of the samples, in descending order, were: AH Plus, Sealapex, iRootSP, MTA Fillapex and gutta-percha. No significant difference was found between the radiopacity values of AH Plus and Sealapex (p>0.05. There were statistically significant differences between these two groups (AH Plus and Sealapex and all other experimental groups (p<0.05. CONCLUSION: AH Plus and Sealapex exhibited the highest radiopacity values among tested groups. In addition, all tested materials fulfilled the minimum standard value requirements suggested by International Standardization Organization and American National Standards Institute.

  12. Digital radiographic evaluation of alveolar bone loss, density and lamina dura integrity on post splinting mandibular anterior with chronic periodontitis

    Science.gov (United States)

    Rafini, F.; Priaminiarti, M.; Sukardi, I.; Lessang, R.

    2017-08-01

    The healing of periodontal splinting can be detected both with clinical and radiographic examination. In this study, the alveolar bone was evaluated by radiographic digital periapical analysis. Periodontal tooth splinting is periodontal support therapy used to prevent periodontal injury during repair and regeneration of periodontal therapy. Radiographic digital periapical analysis of alveolar bone in the mandibular anterior region with chronic periodontitis and 2/3 cervical bone loss after three months of periodontal splinting. Eighty four proximal site (43 mesial and 41 distal) from 16 patients with chronic periodontitis and treated with spinting were examined by taking periapical digital radiographic at day 1 and 91. The bone loss, bone density and utility of lamina dura were evaluated. The statistical analysis after three months evaluation using T-test for bone loss, Wilcoxon sign rank test for bone density and utility lamina dura showed no significantly differences (pchronic periodontitis with 2/3 alveolar bone loss after three months splinting.

  13. Evaluation of proximal caries in images resulting from different modes of radiographic digitalization.

    Science.gov (United States)

    Xavier, C R G; Araujo-Pires, Ana Claudia; Poleti, M L; Rubira-Bullen, I R F; Ferreira, O; Capelozza, A L A

    2011-09-01

    The aim of this study was to evaluate the performances of observers in diagnosing proximal caries in digital images obtained from digital bitewing radiographs using two scanners and four digital cameras in Joint Photographic Experts Group (JPEG) and tagged image file format (TIFF) files, and comparing them with the original conventional radiographs. In total, 56 extracted teeth were radiographed with Kodak Insight film (Eastman Kodak, Rochester, NY) in a Kaycor Yoshida X-ray device (Kaycor X-707; Yoshida Dental Manufacturing Co., Tokyo, Japan) operating at 70 kV and 7 mA with an exposure time of 0.40 s. The radiographs were obtained and scanned by CanonScan D646U (Canon USA Inc., Newport News, VA) and Genius ColorPage HR7X (KYE Systems Corp. America, Doral, FL) scanners, and by Canon Powershot G2 (Canon USA Inc.), Canon RebelXT (Canon USA Inc.), Nikon Coolpix 8700 (Nikon Inc., Melville, NY), and Nikon D70s (Nikon Inc.) digital cameras in JPEG and TIFF formats. Three observers evaluated the images. The teeth were then observed under the microscope in polarized light for the verification of the presence and depth of the carious lesions. The probability of no diagnosis ranged from 1.34% (Insight film) to 52.83% (CanonScan/JPEG). The sensitivity ranged from 0.24 (Canon RebelXT/JPEG) to 0.53 (Insight film), the specificity ranged from 0.93 (Nikon Coolpix/JPEG, Canon Powershot/TIFF, Canon RebelXT/JPEG and TIFF) to 0.97 (CanonScan/TIFF and JPEG) and the accuracy ranged from 0.82 (Canon RebelXT/JPEG) to 0.91 (CanonScan/JPEG). The carious lesion diagnosis did not change in either of the file formats (JPEG and TIFF) in which the images were saved for any of the equipment used. Only the CanonScan scanner did not have adequate performance in radiography digitalization for caries diagnosis and it is not recommended for this purpose.

  14. 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

  15. 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)

  16. Synthetic digital radiographs using exposure computer models of Voxels / EGS4 Phantoms

    International Nuclear Information System (INIS)

    Kenned, Roberto; Vieira, Jose W.; Lima, Fernando R.A.; Loureiro, Eduardo

    2008-01-01

    The objective of this work is to produce synthetic digital radiographs from synthetic phantoms with the use of a Computational Model of Exposition (MCE). The literature explains a model consisted on a phantom, a Monte Carlo code and an algorithm of a radioactive source. In this work it was used the FAX phantom (Female Adult voXel), besides the EGS4 system code Eletron Shower-range version 4) and an external source, similar to that used in diagnostic radiology. The implementation of MCE creates files with information on external energy deposited in the voxels of fantoma used, here called EnergiaPorVoxel.dat. These files along with the targeted phantom (fax.sgi) worked as data entry for the DIP software (Digital Imaging Processing) to build the synthetic phantoms based on energy and the effective dose. This way you can save each slice that is the stack of pictures of these phantoms synthetics, which have been called synthetic digital radiography. Using this, it is possible to use techniques of emphasis in space to increase the contrast or elineate contours between organs and tissues. The practical use of these images is not only to allow a planning of examinations performed in clinics and hospitals and reducing unnecessary exposure to patients by error of radiographic techniques. (author)

  17. A study of trabecular bone strength and morphometric analysis of bone microstructure from digital radiographic image

    International Nuclear Information System (INIS)

    Han, Seung Yun; Lee, Sun Bok; Oh, Sung Ook; Heo, Min Suk; Lee, Sam Sun; Choi, Soon Chul; Park, Tae Won; Kim, Jong Dae

    2003-01-01

    To evaluate the relationship between morphometric analysis of microstructure from digital radiographic image and trabecular bone strength. One hundred eleven bone specimens with 5 mm thickness were obtained from the mandibles of 5 pigs. Digital images of specimens were taken using a direct digital intraoral radiographic system. After selection of ROI(100 x 100 pixel) within the trabecular bone, mean gray level and standard deviation were obtained. Fractal dimension and the variants of morphometric analysis (trabecular area, periphery, length of skeletonized trabeculae, number of terminal point, number of branch point) were obtained from ROI. Punch sheer strength analysis was performed using Instron (model 4465, Instron Corp., USA). The loading force (loading speed 1mm/min) was applied to ROI of bone specimen by a 2 mm diameter punch. Stress-deformation curve was obtained from the punch sheer strength analysis and maximum stress, yield stress, Young's modulus were measured. Maximum stress had a negative linear correlation with mean gray level and fractal dimension significantly (p<0.05). Yield stress had a negative linear correlation with mean gray level, periphery, fractal dimension and the length of skeletonized trabeculae significantly (p<0.05). Young's modulus had a negative linear correlation with mean gray level and fractal dimension significantly (p<0.05). The strength of cancellous bone exhibited a significantly linear relationship between mean gray level, fractal dimension and morphometric analysis. The methods described above can be easily used to evaluate bone quality clinically.

  18. 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

  19. Improvement of density resolution in short-pulse hard x-ray radiographic imaging using detector stacks

    Energy Technology Data Exchange (ETDEWEB)

    Borm, B.; Gärtner, F.; Khaghani, D. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); Johann Wolfgang Goethe-Universität, Frankfurt am Main (Germany); Neumayer, P. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany)

    2016-09-15

    We demonstrate that stacking several imaging plates (IPs) constitutes an easy method to increase hard x-ray detection efficiency. Used to record x-ray radiographic images produced by an intense-laser driven hard x-ray backlighter source, the IP stacks resulted in a significant improvement of the radiograph density resolution. We attribute this to the higher quantum efficiency of the combined detectors, leading to a reduced photon noise. Electron-photon transport simulations of the interaction processes in the detector reproduce the observed contrast improvement. Increasing the detection efficiency to enhance radiographic imaging capabilities is equally effective as increasing the x-ray source yield, e.g., by a larger drive laser energy.

  20. Use of digitally reconstructed radiographs in radiotherapy treatment planning and verification

    International Nuclear Information System (INIS)

    Yang, C.; Guiney, M.; Hughes, P.; Leung, S.; Liew, K.H.; Matar, J.; Quong, G.

    2000-01-01

    The authors present 3 years of experience of using digitally reconstructed radiographs (DRR) for radiotherapy planning and verification. Comparison is made with simulation film (SF) to illustrate the advantages of DRR over SF. Emphasis is placed on using the appropriate equipment and applying the correct technique. A brief discourse on the principle of CT imaging is presented to illustrate the operation of CT software and optimization of image display for axial slices and DRR. Emphasis placed on the application of clinical knowledge to enhance the usefulness as well as the technical quality of the DRR. Illustrative examples are given. Copyright (1999) Blackwell Science Pty Ltd

  1. 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.

  2. Accuracy of templating the acetabular cup size in Total Hip Replacement using conventional acetate templates on digital radiographs.

    Science.gov (United States)

    Krishnamoorthy, Vignesh P; Perumal, Rajamani; Daniel, Alfred J; Poonnoose, Pradeep M

    2015-12-01

    Templating of the acetabular cup size in Total Hip Replacement (THR) is normally done using conventional radiographs. As these are being replaced by digital radiographs, it has become essential to create a technique of templating using digital films. We describe a technique that involves templating the digital films using the universally available acetate templates for THR without the use of special software. Preoperative digital radiographs of the pelvis were taken with a 30 mm diameter spherical metal ball strapped over the greater trochanter. Using standard acetate templates provided by the implant company on magnified digital radiographs, the size of the metal ball (X mm) and acetabular cup (Y mm) were determined. The size of the acetabular cup to be implanted was estimated using the formula 30*Y/X. The estimated size was compared with the actual size of the cup used at surgery. Using this technique, it was possible to accurately predict the acetabular cup size in 28/40 (70%) of the hips. When the accuracy to within one size was considered, templating was correct in 90% (36/40). When assessed by two independent observers, there was good intra-observer and inter-observer reliability with intra-class correlation coefficient values greater than 0.8. It was possible to accurately and reliably predict the size of the acetabular cup, using acetate templates on digital films, without any digital templates.

  3. 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.))

  4. The benefit of accounting for DQE variations in simulated dose reduction of digital radiographic systems

    International Nuclear Information System (INIS)

    Svalkvist, A.; Baath, M.

    2010-01-01

    Adding noise to clinical radiographs to simulate dose reduction can be used to investigate the relationship between dose level and clinical image quality without exposing patients to additional radiation. The purpose of the present paper was to examine the benefits of using a method that accounts for detective quantum efficiency (DQE) variations that may occur in different dose ranges in the simulated dose reduction process. A method initially intended for simulated dose reduction in tomo-synthesis was applied to extremely low-dose posterio-anterior radiographs of an anthropomorphic chest phantom, selected from a group of projection images included in a tomo-synthesis examination and compared with a previous method that do not account for DQE variations. A comparison of images simulated to be collected at a lower dose level (73% of the original dose level) and images actually collected at this lower dose level revealed that the error in the integrated normalised noise power spectrum was smaller than 4% for the method that accounts for DQE variations in the simulated dose reduction, whereas the error was larger than 20% for the previous method. This indicates that an increased validity in dose reduction simulation of digital radiographic systems is obtained with a method accounting for DQE variations. (authors)

  5. Tooth coronal index: Key for age estimation on digital panoramic radiographs

    Directory of Open Access Journals (Sweden)

    Ravleen Nagi

    2018-01-01

    Full Text Available Background: Assessment of age through teeth is one of the most reliable and simple method than skeletal remains, to calculate age of an individual. Objectives: The study was carried out with an aim to evaluate reliability of dental age assessment through tooth coronal index (TCI method. Materials and Methods: The digital panoramic radiographs of 100 subjects of Chhattisgarh aged 20–70 years were selected for the study. The measurements were performed on the JPEG images of selected panoramic radiographs by using Adobe Acrobat 7.0 professional software. The height of the crown, i.e., coronal height, and the height of the coronal pulp cavity, i.e., coronal pulp cavity height, of mandibular second premolars and first molars were measured in millimeter (mm and then TCI was calculated for each tooth. Actual age of a subject was compared with TCI of tooth and the acquired data were subjected to Pearson's correlation and unpaired t-tests. Results: Negative correlation was observed between the real age and TCI of mandibular first molar (r = −0.092, P = 0.365 and second premolar (r = −0.168, P = 0.096. Statistically significant difference was observed between real age and TCI for mandibular second premolar and first molar (P = 0.000 by unpaired t-test. Conclusion: TCI has the potential to estimate age of an individual on dental radiographs. It is simple, cost effective than histological methods and can be applied to both living and unknown dead.

  6. Perona Malik anisotropic diffusion model using Peaceman Rachford scheme on digital radiographic image

    International Nuclear Information System (INIS)

    Halim, Suhaila Abd; Razak, Rohayu Abd; Ibrahim, Arsmah; Manurung, Yupiter HP

    2014-01-01

    In image processing, it is important to remove noise without affecting the image structure as well as preserving all the edges. Perona Malik Anisotropic Diffusion (PMAD) is a PDE-based model which is suitable for image denoising and edge detection problems. In this paper, the Peaceman Rachford scheme is applied on PMAD to remove unwanted noise as the scheme is efficient and unconditionally stable. The capability of the scheme to remove noise is evaluated on several digital radiography weld defect images computed using MATLAB R2009a. Experimental results obtained show that the Peaceman Rachford scheme improves the image quality substantially well based on the Peak Signal to Noise Ratio (PSNR). The Peaceman Rachford scheme used in solving the PMAD model successfully removes unwanted noise in digital radiographic image

  7. Perona Malik anisotropic diffusion model using Peaceman Rachford scheme on digital radiographic image

    Energy Technology Data Exchange (ETDEWEB)

    Halim, Suhaila Abd; Razak, Rohayu Abd; Ibrahim, Arsmah [Center of Mathematics Studies, Faculty of Computer and Mathematical Sciences, Universiti Teknologi MARA, 40450 Shah Alam. Selangor DE (Malaysia); Manurung, Yupiter HP [Advanced Manufacturing Technology Excellence Center (AMTEx), Faculty of Mechanical Engineering, Universiti Teknologi MARA, 40450 Shah Alam. Selangor DE (Malaysia)

    2014-06-19

    In image processing, it is important to remove noise without affecting the image structure as well as preserving all the edges. Perona Malik Anisotropic Diffusion (PMAD) is a PDE-based model which is suitable for image denoising and edge detection problems. In this paper, the Peaceman Rachford scheme is applied on PMAD to remove unwanted noise as the scheme is efficient and unconditionally stable. The capability of the scheme to remove noise is evaluated on several digital radiography weld defect images computed using MATLAB R2009a. Experimental results obtained show that the Peaceman Rachford scheme improves the image quality substantially well based on the Peak Signal to Noise Ratio (PSNR). The Peaceman Rachford scheme used in solving the PMAD model successfully removes unwanted noise in digital radiographic image.

  8. Optimisation of the digital radiographic imaging of suspected non-accidental injury

    Science.gov (United States)

    Offiah, Amaka

    Aim: To optimise the digital (radiographic) imaging of children presenting with suspected non-accidental injury (NAI). Objectives: (i) To evaluate existing radiographic quality criteria, and to develop a more suitable system if these are found to be inapplicable to skeletal surveys obtained in suspected NAI. (ii) To document differences in image quality between conventional film-screen and the recently installed Fuji5000R computed radiography (CR) system at Great Ormond Street Hospital for Children, (iii) To document the extent of variability in the standard of skeletal surveys obtained in the UK for suspected NAI. (iv) To determine those radiographic parameters which yield the highest diagnostic accuracy, while still maintaining acceptable radiation dose to the child, (v) To determine how varying degrees of edge-enhancement affect diagnostic accuracy. (vi) To establish the accuracy of soft compared to hard copy interpretation of images in suspected NAI. Materials and Methods: (i) and (ii) Retrospective analysis of 286 paediatric lateral spine radiographs by two observers based on the Commission of European Communities (CEC) quality criteria, (iii) Review of the skeletal surveys of 50 consecutive infants referred from hospitals throughout the United Kingdom (UK) with suspected NAI. (iv) Phantom studies. Leeds TO. 10 and TO. 16 test objects were used to compare the relationship between film density, exposure parameters and visualisation of object details, (iv) Clinical study. Anteroposterior and lateral post mortem skull radiographs of six consecutive infants were obtained at various exposures. Six observers independently scored the images based on visualisation of five criteria, (v) and (vi) A study of diagnostic accuracy in which six observers independently interpreted 50 radiographs from printed copies (with varying degrees of edge-enhancement) and from a monitor. Results: The CEC criteria are useful for optimisation of imaging parameters and allow the detection

  9. Determining paediatric patient thickness from a single digital radiograph-a proof of principle.

    Science.gov (United States)

    Worrall, Mark; Vinnicombe, Sarah; Sutton, David G

    2018-04-05

    This work presents a proof of principle for a method of estimating the thickness of an attenuator from a single radiograph using the image, the exposure factors with which it was acquired and a priori knowledge of the characteristics of the X-ray unit and detector used for the exposure. It is intended this could be developed into a clinical tool to assist with paediatric patient dose audit, for which a measurement of patient size is required. The proof of principle used measured pixel value and effective linear attenuation coefficient to estimate the thickness of a Solid Water attenuator. The kerma at the detector was estimated using a measurement of pixel value on the image and measured detector calibrations. The initial kerma was estimated using a lookup table of measured output values. The effective linear attenuation coefficient was measured for Solid Water at varying kV p . 11 test images of known and varying thicknesses of Solid Water were acquired at 60, 70 and 81 kV p . Estimates of attenuator thickness were made using the model and the results compared to the known thickness. Estimates of attenuator thickness made using the model differed from the known thickness by 3.8 mm (3.2%) on average, with a range of 0.5-10.8 mm (0.5-9%). A proof of principle is presented for a method of estimating the thickness of an attenuator using a single radiograph of the attenuator. The method has been shown to be accurate using a Solid Water attenuator, with a maximum difference between estimated and known attenuator thickness of 10.8 mm (9%). The method shows promise as a clinical tool for estimating abdominal paediatric patient thickness for paediatric patient dose audit, and is only contingent on the type of data routinely collected by Medical Physics departments. Advances in knowledge: A computational model has been created that is capable of accurately estimating the thickness of a uniform attenuator using only the radiographic image, the exposure factors with which

  10. Digital panoramic radiograph rejection index at a Dental Radiology Service in Paraná, Brazil

    International Nuclear Information System (INIS)

    Mickus, J.; Barros, F.S.; Sato, G.Y.; Rosa, P.C.

    2017-01-01

    Panoramic radiography is the most frequent extraoral examination in dentistry. This technique allows the visualization of adjacent maxillomandibular and anatomical structures. Although digital imaging systems are already the great majority of dental radiology services, there is still a shortage of works evaluating the quality of this type of image. The objective of this study was to identify the rejection index of digital panoramic radiographs of a dental radiology service of a university in Brazil, pointing out the main reasons. A survey was performed on the image files and, randomly selected, 2306 images, 10% of the examinations performed in the period between 2013 to 2015. The results indicated a total rejection rate of 5.1% over the three years, totaling 117 radiographs. The main reasons for rejection were: the patient's head tilted backwards in 2013 and the lack of tongue contact with the palate, for the years 2014 and 2015. The main reasons for repetition of exams are related to the positioning in the execution of the technique radiological factors, which may be related to the lack of professional training. Patient collaboration during the examination and professional-to-patient communication failures may result in poor diagnostic quality exams

  11. In Vitro Evaluation of Proximal Carious Lesions Using Digital Radiographic Systems

    Directory of Open Access Journals (Sweden)

    Mayana Soares Vieira

    2015-01-01

    Full Text Available The study aimed to compare the sensitivity and specificity of digital radiographic systems for the diagnosis of proximal carious lesions. Extracted human teeth (3 canines, 3 premolars, and 3 molars were submitted to one of three types of proximal lesions (demineralized area, cavity affecting the enamel alone, and cavity affecting enamel and dentin. Bitewing radiographs were obtained from each system (Sirona, Kodak, and Schick and evaluated by 12 raters (4 dental students, 4 radiology specialists, and 4 dentists. The chi-squared test was used to determine the frequency of correct diagnoses among the different systems, raters, teeth, and types of lesion. Sensitivity and specificity regarding demineralized areas were calculated for each system. The frequencies of correct diagnoses were found: Schick (70.8%, Kodak (63.9%, Sirona (59.0%, specialists (69.4%, students (62.5%, dentists (61.8%, premolars (70.1%, canines (65.3%, and molars (58.3%. No significant differences were found among the different systems, raters, or teeth (P>0.05. Sensitivity and specificity were 0.64 and 0.47 (Schick, 0.56 and 0.50 (Sirona, and 0.48 and 0.58 (Kodak. The most correct diagnoses were achieved using the Schick digital system on premolars and evaluated by specialists in radiology. The systems demonstrated low sensitivity and specificity for the diagnosis of demineralized areas.

  12. A study of the mandibular canal in digital panoramic radiographic images of a selected Korean population

    International Nuclear Information System (INIS)

    Kim, Jae Duk; Kim, Jin Soo

    2007-01-01

    To determine the more valuable information to detect the mandibular canal and the mental foramen in panoramic radiographs of a selected Korean population for the implant. This study analysed 288 panoramic radiographic images of patients taken at the Dental hospital of Chosun University retrospectively. Indirect digital panoramic X-ray machine (ProlineXC, PLANMECA, Finland) with processing by using Directview CR950 (Kodak, U.S.A.) and Direct digital panoramic X-ray machine (Promax, PLANMECA, Finland) were used for all exposures. All images were converted into Dicom format. The common position of the mental foramen was in line with the longitudinal axis of the second premolar (68.1%). The mental foramen was lower symmetrical in 81.8% of cases. The mandibular canal was not identified at anterior portion and discontinued with the mental foramen in 27.8% of all cases, in 42.4% identified with lower border line continued with the mental foramen, in 14.6% with both upper and lower border lines, and in 15.3% unilaterally identified with lower border line. Clinicians can estimate the upper border line of the mandibular canal from the confirmation of the mental foramen and the lower border line of the mandibular canal symmetrically on the panoramic radiography taken in adjusted midsaggital plane of patient's head

  13. Effect of changing the kilovoltage peak on radiographic caries assessment in digital and conventional radiography

    Energy Technology Data Exchange (ETDEWEB)

    Zayet, Mohamed Khalifa; Helaly, Yara Rabee; Eiid, Salma Belal [Dept. of Oral Radiology, Faculty of Oral and Dental Medicine, Cairo University, Cairo (Egypt)

    2014-09-15

    This study aimed to investigate the effect of changing the kilovoltage peak (kVp) on the radiographic assessment of dental caries. Seventy-five extracted posterior teeth with proximal caries or apparently sound proximal surfaces were radiographed with conventional E-speed films and a photostimulable phosphor system using 60 kVp and 70 kVp for the caries assessment. The images were evaluated by three oral radiologists and compared with the results of the stereomicroscope analysis. No statistically significant difference was found between 60 kVp and 70 kVp for the caries detection, determination of caries extension into dentin, and caries severity in either the conventional or the digital images. Good to very good inter-observer and intra-observer agreements were found for both kilovoltage values on the conventional and digital images. Changing the kilovoltage between 60 kVp and 70 kVp had no obvious effect on the detection of proximal caries or determination of its extension or severity.

  14. Effect of changing the kilovoltage peak on radiographic caries assessment in digital and conventional radiography

    International Nuclear Information System (INIS)

    Zayet, Mohamed Khalifa; Helaly, Yara Rabee; Eiid, Salma Belal

    2014-01-01

    This study aimed to investigate the effect of changing the kilovoltage peak (kVp) on the radiographic assessment of dental caries. Seventy-five extracted posterior teeth with proximal caries or apparently sound proximal surfaces were radiographed with conventional E-speed films and a photostimulable phosphor system using 60 kVp and 70 kVp for the caries assessment. The images were evaluated by three oral radiologists and compared with the results of the stereomicroscope analysis. No statistically significant difference was found between 60 kVp and 70 kVp for the caries detection, determination of caries extension into dentin, and caries severity in either the conventional or the digital images. Good to very good inter-observer and intra-observer agreements were found for both kilovoltage values on the conventional and digital images. Changing the kilovoltage between 60 kVp and 70 kVp had no obvious effect on the detection of proximal caries or determination of its extension or severity.

  15. 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.)

  16. An evaluation of the impact of digital imaging on radiographic practice and patient doses

    Science.gov (United States)

    Horrocks, J.; Violaki, K.

    2015-09-01

    Direct digital imaging technology was implemented in all areas in general and mobile radiology at Barts and the Royal London Hospitals in 2012. Evidence from recent radiation incident investigations indicates optimum exposure factors are not consistently selected, with the greater dynamic range of the digital detectors allowing sub-optimal practice. To investigate further patient dose data were extracted from the Radiology Information System for adult chest X-ray examinations in 2014, covering over 50,000 studies in the Trust. Chest X-ray examinations were selected as they are low dose but frequent examinations. The patient dose data were evaluated taking into account X-ray system type and detector performance measurements, and individual cases studies were used to highlight where practice can be improved.

  17. Digital evaluation of the influence of interruption of the fixation process on radiographic contrast and base-plus-fog density in three commercial brands of radiographic films

    Directory of Open Access Journals (Sweden)

    Paula Verona Ragusa da Silva

    Full Text Available INTRODUCTION : With the interest in anticipating access to the result of intraoral radiography, the radiographic processing is frequently neglected, compromising image quality. OBJECTIVE : The aim of this study was to evaluate the influence of interrupting the fixation process on the radiographic contrast and base-plus-fog density (BPFD in three brands of periapical films. MATERIAL AND METHOD : Ninety radiographs were taken of an aluminum stepwedge and a lead plate for each brand, and they were divided according to the time of initial immersion in the fixative in: control group (without interrupting the fixing, 5, 10, 20, 30 and 40 seconds. During processing, films had the fixing stage stopped and were exposed to a negatoscope for 1 minute, then the fixation time of 10 minutes was completed. The radiographs were digitized and exported to Image Tool 3.0.software. RESULT : Kodak(r film showed no statistically significant differences between groups, while Agfa(r film presented difference in BPFD compared with Group 5 seconds, and Dentix(r film showed statistical difference in all groups in comparison with the control group. CONCLUSION : Under the conditions studied, Kodak(r film is not influenced by disruption of fixation as regards BPFD and image contrast, enabling early access to the results of radiographs, whereas Agfa(r film requires at least 10 seconds of initial fixation, and Dentix(r film obtains better results when the process of fixation is not interrupted.

  18. Digital radiographic evaluation of the midpalatal suture in patients submitted to rapid maxillary expansion

    Directory of Open Access Journals (Sweden)

    Maria de Fátima Batista de Melo

    2013-01-01

    Full Text Available Aims: To analyze the density of the midpalatal suture by means of digital radiographs three months after retention to evaluate if this period of retention is really sufficient for bone repair. Materials and Methods: This prospective study consisted of 31 patients (11 girls and 20 boys in the mixed or permanent dentition stage, treated using a tooth-tissue borne expanders (Haas. Occlusal digital radiographs were taken at three stages: prior to rapid maxillary expansion (Stage I; immediately after desired maxillary expansion (Stage II; and after three months of retention (Stage III. Radiographs were taken on a dental X-ray machine, set at 70 kVp and 7 mA with an exposure time of 0.04 s. A phosphor storage plate system, imaging plate size n. 2 (35 × 45 × 1.6 mm, was used. Three regions (A, B and C measured 0.02 mm² were selected for optical density analysis. The difference between the measurements was evaluated with the paired t-test. Results: The optical density was reduced at Stages II and III compared with Stage I. Between-stage comparison showed statistically significant changes for all variables (P < 0.05, with the highest mean optical density at Stage I and the lowest at Stage II, in all groups. Actually, there was an increase in optical density between Stages II and III, but they are reduced compared with Stage I. Conclusion: The results strongly suggest that bone formation did not occur as expected, and that a longer retention period for bone repair may be necessary.

  19. Invesigation of prevalence of dental anomalies by using digital panoramic radiographs.

    Science.gov (United States)

    Bilge, Nebiha Hilal; Yeşiltepe, Selin; Törenek Ağırman, Kübra; Çağlayan, Fatma; Bilge, Osman Murat

    2017-09-21

    This study was performed to evaluate the prevalence of all types and subtypes of dental anomalies among 6 to 40 year-old patients by using panoramic radiographs. This cross-sectional study was conducted by analyzing digital panoramic radiographs of 1200 patients admitted to our clinic in 2014. Dental anomalies were examined under 5 types and 16 subtypes. Dental anomalies were divided into five types: (a) number (including hypodontia, oligodontia and hyperdontia); (b) size (including microdontia and macrodontia); (c) structure (including amelogenesis imperfecta, dentinogenesis imperfecta and dentin dysplasia); (d) position (including transposition, ectopia, displacement, impaction and inversion); (e) shape (including fusion-gemination, dilaceration and taurodontism); RESULTS: The prevalence of dental anomalies diagnosed by panoramic radiographs was 39.2% (men (46%), women (54%)). Anomalies of position (60.8%) and shape (27.8%) were the most common types of abnormalities and anomalies of size (8.2%), structure (0.2%) and number (17%) were the least in both genders. Anomalies of impaction (45.5%), dilacerations (16.3%), hypodontia (13.8%) and taurodontism (11.2%) were the most common subtypes of dental anomalies. Taurodontism was more common in the age groups of 13-19 years. The age range of the most frequent of all other anomalies was 20-29. Anomalies of tooth position were the most common type of dental anomalies and structure anomalies were the least in this Turkish dental population. The frequency and type of dental anomalies vary within and between populations, confirming the role of racial factors in the prevalence of dental anomalies. Digital panoramic radiography is a very useful method for the detection of dental anomalies.

  20. 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

  1. Digital radiograph of the middle phalanx of the third finger (MP3) region as a tool for skeletal maturity assessment.

    Science.gov (United States)

    Hegde, Deepa Y; Baliga, Sudhindra; Yeluri, Ramakrishna; Munshi, A K

    2012-01-01

    To evaluate the reliability of the digital radiograph of the middle phalanx of the third finger (MP3) in skeletal maturity assessment. Fifty children (24 girls and 26 boys) belonging to the circumpubertal age-group were selected for the study. Two radiographs - lateral cephalogram and digital radiograph of the MP3 region - were taken in each child. Age assessment was based on the changes in shape of the cervical vertebrae and the epiphysis of the middle phalanx of the third finger of the left hand. The radiographs were assessed by three examiners. The inter- and intraexaminer variability were determined by the Wilcoxon rank sign test and the Kruskal-Wallis test and were found to be nonsignificant. Examiner 3 showed the best intraexaminer agreement and was selected to evaluate the radiographs for the entire study. The correlation determined between the MP3 stages and cervical vertebrae maturity index (CVMI) stages, the peak-wise distribution of the MP3 stages, and the correlation between the MP3 stages and the chronological age were found to be highly significant. Digital radiograph of the MP3 region is definitely a simple, reliable, cost-effective, and time-saving technique for the assessment of skeletal maturity.

  2. 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

  3. 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

  4. A Medipix2-based imaging system for digital mammography with silicon pixel detectors

    CERN Document Server

    Bisogni, M G; Fantacci, M E; Mettivier, G; Montesi, M C; Novelli, M; Quattrocchi, M; Rosso, V; Russo, P; Stefanini, A

    2004-01-01

    In this paper we present the first tests of a digital imaging system based on a silicon pixel detector bump-bonded to an integrated circuit operating in single photon counting mode. The X-rays sensor is a 300 mu m thick silicon, 14 by 14 mm/sup 2/, upon which a matrix of 256 * 256 pixels has been built. The read-out chip, named MEDIPIX2, has been developed at CERN within the MEDIPIX2 Collaboration and it is composed by a matrix of 256 * 256 cells, 55 * 55 mu m/sup 2/. The spatial resolution properties of the system have been assessed by measuring the square wave resolution function (SWRF) and first images of a standard mammographic phantom were acquired using a radiographic tube in the clinical irradiation condition. (5 refs).

  5. Teleradiology in a neonatal intensive care unit: Comparison between the interpretation of transmitted digital images and film radiographs

    International Nuclear Information System (INIS)

    McFee, W.H.; Bramson, R.T.; Cates, J.D.; Curran, J.S.

    1987-01-01

    Using a Raytel teleradiology system, a prospective comparison was made between the interpretations of 700 transmitted digital images and the film radiographs from which these digital images were made. The original films consisted of all of the radiographs obtained from the infants in a 40-bed level III neonatal intensive care unit over a 6-week period. Interpretations were done by two radiologists, initially from transmitted images and subsequently from the original films. Comparison of the interpretations demonstrates a remarkably high degree of correlation, with less than 0.5% clinically significant discrepancies reported

  6. 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

  7. A Comparison of Radiographic Film Densitometry Using a New Computerized Tool with a Digital Densitometer

    Directory of Open Access Journals (Sweden)

    Hoorieh Bashizadeh Fakhar

    2016-11-01

    Full Text Available Objectives: The purpose of this study was to develop and test a new tool for radiographic densitometry by combining periapical films and aluminum step wedge.Materials and Methods: We reviewed 50 Kodak E-speed intraoral films. An aluminum step wedge consisting of 16 steps was constructed. Each step was 1mmx3mx10mm. The step wedge was exposed to varying exposure times, ranging from 0.05 second to 0.5 second, increasing in 0.05 second increments. Films were digitalized after processing and the MATLAB software algorithm was ran subsequently. Density of the films was measured again using a digital densitometer. In order to compare the two imaging techniques, three steps were selected. Output data from the MATLAB algorithm were compared with data obtained from the digital densitometer.Results: The new method could detect significant differences between subsequent exposure times in step 7, while the densitometer did that in steps 7 and 12. The new method’s sensitivity in determining density changes was 5.26%, 84.1% and 93.02% in steps 2, 7, and 12 respectively.Conclusions: Our new method has an acceptable sensitivity for determining density changes of at least 7 mmEq/Al.Keywords: Densitometry; Image Processing, Computer-Assisted; Aluminum; Phantoms, Imaging

  8. Radiopacity of Methacrylate and Silorane Composite Resins Using a Digital Radiographic System.

    Science.gov (United States)

    Firoozmand, Leily Macedo; Cordeiro, Mariana Gonçalves; Da Silva, Marcos André Dos Santos; De Jesus Tavarez, Rudys Rodolfo; Matos Maia Filho, Etevaldo

    The aim of this study was to evaluate the radiopacity of silorane and methacrylate resin composites, comparing them to the enamel, dentin, and aluminum penetrometer using a digital image. From six resin composites (Filtek ™ P90, Filtek Z350, Filtek Z350 XT flow, Tetric Ceram, TPH Spectrum, and SureFil SDR flow) cylindrical disks (5 × 1 mm) were made and radiographed by a digital method, together with a 15-step aluminum step-wedge and a 1 mm slice of human tooth. The degree of radiopacity of each image was quantified using digital image processing. The mean values of the shades of gray of the tested materials were measured and the equivalent width of aluminum was calculated for each resin. The results of our work yielded the following radiopacity values, given here in descending order: Tetric Ceram > TPH > SDR > Z350 > Z350 flow > P90 > enamel > dentin. The radiopacity of the materials was different both for the enamel and for the dentin, except for resin P90, which was no different than enamel. In conclusion, silorane-based resin exhibited a radiopacity higher than dentin and closest to the enamel; a large portion of the methacrylate-based flow and conventional resins demonstrated greater radiopacity in comparison to dentin and enamel.

  9. Radiopacity of Methacrylate and Silorane Composite Resins Using a Digital Radiographic System

    Directory of Open Access Journals (Sweden)

    Leily Macedo Firoozmand

    2016-01-01

    Full Text Available The aim of this study was to evaluate the radiopacity of silorane and methacrylate resin composites, comparing them to the enamel, dentin, and aluminum penetrometer using a digital image. From six resin composites (Filtek™ P90, Filtek Z350, Filtek Z350 XT flow, Tetric Ceram, TPH Spectrum, and SureFil SDR flow cylindrical disks (5 × 1 mm were made and radiographed by a digital method, together with a 15-step aluminum step-wedge and a 1 mm slice of human tooth. The degree of radiopacity of each image was quantified using digital image processing. The mean values of the shades of gray of the tested materials were measured and the equivalent width of aluminum was calculated for each resin. The results of our work yielded the following radiopacity values, given here in descending order: Tetric Ceram > TPH > SDR > Z350 > Z350 flow > P90 > enamel > dentin. The radiopacity of the materials was different both for the enamel and for the dentin, except for resin P90, which was no different than enamel. In conclusion, silorane-based resin exhibited a radiopacity higher than dentin and closest to the enamel; a large portion of the methacrylate-based flow and conventional resins demonstrated greater radiopacity in comparison to dentin and enamel.

  10. Effect of two X-ray tube voltages on detection of approximal caries in digital radiographs. An in vitro study.

    Science.gov (United States)

    Hellén-Halme, Kristina

    2011-04-01

    This study evaluated the effect of two different tube voltages on clinicians' ability to diagnose approximal carious lesions in digital radiographs. One hundred extracted teeth were radiographed twice at two voltage settings, 60 and 70 kV, using a standardized procedure. Seven observers evaluated the radiographs on a standard color monitor pre-calibrated according to DICOM part 14. Evaluations were made at ambient light levels below 50 lx. All observations were analyzed with receiver operating characteristic curves. A histological examination of the teeth served as the criterion standard. A paired t test compared the effects of the two voltages. The significance level was set to p < 0.05. Weighted kappa statistics estimated intra-observer agreement. No significant difference in accuracy of approximal carious lesion diagnosis was found between the two voltage settings. But five observers rated dentin lesions on radiographs exposed at 70 kV better than on radiographs exposed at 60 kV. Intra-observer agreement differed from fair to moderate. There was no significant difference in accuracy of approximal carious lesion diagnosis between digital radiographs exposed with 60 or 70 kV.

  11. Development of automatic radiographic inspection system using digital image processing and artificial intelligence

    International Nuclear Information System (INIS)

    Itoga, Kouyu; Sugimoto, Koji; Michiba, Koji; Kato, Yuhei; Sugita, Yuji; Onda, Katsuhiro.

    1991-01-01

    The application of computers to welding inspection is expanding rapidly. The classification of the application is the collection, analysis and processing of data, the graphic display of results, the distinction of the kinds of defects and the evaluation of the harmufulness of defects and the judgement of acceptance or rejection. The application of computer techniques to the automation of data collection was realized at the relatively early stage. Data processing and the graphic display of results are the techniques in progress now, and the application of artificial intelligence to the distinction of the kinds of defects and the evaluation of harmfulness is expected to expand rapidly. In order to computerize radiographic inspection, the abilities of image processing technology and knowledge engineering must be given to computers. The object of this system is the butt joints by arc welding of the steel materials of up to 30 mm thickness. The digitizing transformation of radiographs, the distinction and evaluation of transmissivity and gradation by image processing, and only as for those, of which the picture quality satisfies the standard, the extraction of defect images, their display, the distinction of the kinds and the final judgement are carried out. The techniques of image processing, the knowledge for distinguishing the kinds of defects and the concept of the practical system are reported. (K.I.)

  12. Evaluation of a digital learning object (DLO) to support the learning process in radiographic dental diagnosis.

    Science.gov (United States)

    Busanello, F H; da Silveira, P F; Liedke, G S; Arús, N A; Vizzotto, M B; Silveira, H E D; Silveira, H L D

    2015-11-01

    Studies have shown that inappropriate therapeutic strategies may be adopted if crown and root changes are misdiagnosed, potentially leading to undesirable consequences. Therefore, the aim of this study was to evaluate a digital learning object, developed to improve skills in diagnosing radiographic dental changes. The object was developed using the Visual Basic Application (VBA) software and evaluated by 62 undergraduate students (male: 24 and female: 38) taking an imaging diagnosis course. Participants were divided in two groups: test group, which used the object and control group, which attended conventional classes. After 3 weeks, students answered a 10-question test and took a practice test to diagnose 20 changes in periapical radiographs. The results show that test group performed better that control group in both tests, with statistically significant difference (P = 0.004 and 0.003, respectively). In overall, female students were better than male students. Specific aspects of object usability were assessed using a structured questionnaire based on the System Usability Scale (SUS), with a score of 90.5 and 81.6 by male and female students, respectively. The results obtained in this study suggest that students who used the DLO performed better than those who used conventional methods. This suggests that the DLO may be a useful teaching tool for dentistry undergraduates, on distance learning courses and as a complementary tool in face-to-face teaching. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. GPU acceleration for digitally reconstructed radiographs using bindless texture objects and CUDA/OpenGL interoperability.

    Science.gov (United States)

    Abdellah, Marwan; Eldeib, Ayman; Owis, Mohamed I

    2015-01-01

    This paper features an advanced implementation of the X-ray rendering algorithm that harnesses the giant computing power of the current commodity graphics processors to accelerate the generation of high resolution digitally reconstructed radiographs (DRRs). The presented pipeline exploits the latest features of NVIDIA Graphics Processing Unit (GPU) architectures, mainly bindless texture objects and dynamic parallelism. The rendering throughput is substantially improved by exploiting the interoperability mechanisms between CUDA and OpenGL. The benchmarks of our optimized rendering pipeline reflect its capability of generating DRRs with resolutions of 2048(2) and 4096(2) at interactive and semi interactive frame-rates using an NVIDIA GeForce 970 GTX device.

  14. Automatic, anatomically selective, artifact-free enhancement of digital chest radiographs

    International Nuclear Information System (INIS)

    Sezan, M.I.; Tekalp, A.M.; Schaetzing, R.

    1988-01-01

    The authors propose a technique for automatic, anatomically selective, artifact-free enhancement of digital chest radiographs. Anatomically selective enhancement is motivated by the different enhancement requirements of the lung field and the mediastinum. A recent peak detection algorithm is applied to the image histogram to automatically determine a gray-level threshold between the lung and mediastinum fields. The gray-level threshold facilitates anatomically selective gray-scale modification and unsharp masking. Further, in an attempt to suppress possible white-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 that varied asymmetrically with positive and negative values of the local image contrast

  15. Comparison of three digital radiographic imaging systems for the visibility of endodontic files

    International Nuclear Information System (INIS)

    Park, Jong Won; Kim, Eun Kyung; Han, Won Jeong

    2004-01-01

    To compare three digital radiographic imaging sensors by evaluating the visibility of endodontic file tips with interobserver reproducibility and assessing subjectively the clarity of images in comparison with the x-ray film images. Forty-five extracted sound premolars were used for this study. Fifteen plaster blocks were made with three premolars each and 8, 10, 15 K-flexofiles were inserted into the root canal of premolars. They were radiographically exposed using periapical x-ray films (Kodak Insight Dental film, Eastmann Kodak company, Rochester, USA), Digora imaging plates (Soredex-Orion Co., Helsinki, Finland), CDX 2000HQ sensors (Biomedisys Co., Seoul, Korea), and CDR sensors (Schick Inc., Long Island, USA). The visibility of endodontic files was evaluated with interobserver reproducibility, which was calculated as the standard deviations of X, Y coordinated of endodontic file tips measured on digital images by three oral and maxillofacial radiologists. The clarity of images was assessed subjectively using 3 grades, i.e, plus, equal, and minus in comparison with the conventional x-ray film images. Interobserver reproducibility of endodontic file tips was the highest in CDR sensor (p<0.05) only except at Y coordinates of 15 file. In the subjective assessment of the image clarity, the plus grade was the most frequent in CDR sensor at all size of endodontic file (p<0.05). CDR sensor was the most superior to the other sensors, CDX 2000HQ sensor and Digora imaging plate in the evaluation of interobserver reproducibility of endodontic file tip and subjective assessment of image clarity.

  16. 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

  17. Can we see enough? A comparative study of film-screen vs digital radiographs in small lesions in rheumatoid arthritis

    International Nuclear Information System (INIS)

    Jagt, E.J. van der; Hofman, S.; Kraft, B.M.; Leeuwen, M.A. van

    2000-01-01

    The aim of this study was to evaluate the performance of digital radiography in the detection of early very small erosions and joint space narrowing in the hands and feet in rheumatoid arthritis. Fifty-three sets of film-screen and digital radiographs of the same hands and feet with very small and sometimes questionable lesions (possible erosions and cysts) were scored independently two times by four investigators. The percentage of lesions found in exactly the same position for each investigator was calculated. Intra-observer agreement between first and second reading in film-screen radiography was 64-76 % (mean 67 %), and in digital radiographs 60-71 % (mean 64 %). Agreement between film-screen and digital radiographs ranged from 54 to 64 % (mean 58 %) in the first reading and from 56 to 66 % (mean 62 %) in the second reading. Overall agreement between both techniques between first and second reading ranged between 62 and 73 % (mean 65 %). Digital radiography of the hands and feet can be used in patients suspected of rheumatoid arthritis and in follow-up of those patients, because small and early erosions can be seen equally well with the digital technique as compared with the conventional film-screen technique. (orig.)

  18. Evaluation of developmental dental anomalies in digital panoramic radiographs in Southeast Iranian Population.

    Science.gov (United States)

    Saberi, Eshagh Ali; Ebrahimipour, Sediqe

    2016-01-01

    The objective of this study was to evaluate the prevalence of dental developmental anomalies in digital panoramic radiographs of the patients referred to the Zahedan medical imaging center and to evaluate the frequency of anomalies regarding the disorders in shape, position and number in the Southeast of Iran. A total of 1172 panoramic radiographs from 581 males and 586 females aged over 16 years were obtained from the files of the Zahedan medical imaging center between the years of 2014 and 2015. The selected radiographs were evaluated in terms of the anomalies such as dilacerations, taurodontism, supernumerary teeth, congenitally missing teeth, fusion, gemination, tooth impaction, tooth transposition, dens invagination, and peg lateral. Then, the anomalies were compared to each other regarding the frequency of the anomaly type (morphological, positional and numerical). Data were evaluated using descriptive statistics such as frequency and percent, and statistical tests such as X(2) at 0.05 significant level using the Statistical Package for the Social Sciences version 16.5. The prevalence of dental anomaly was 213 (18.17%), which was higher in females (9.90) than male, (8.28), however, this difference was not statistically significant (P > 0.05). The prevalence of dilacerated teeth was 62 (5.29%), taurodontism 63 (5.38%), supernumerary teeth 6 (0.51%), congenitally missing teeth 13 (1.11%), fusion 1 (0.09%), gemination 1 (0.09%), impaction 40 (3.41%), transposition 2 (0.18%), dens invagination 16 (1.37) and peg lateral was 9 (0.77%). The prevalence of morphological anomaly was 152 (71.36%), malposition 42 (19.72%) and numerous anomaly was 19 (8.92%). Dental anomalies are relatively common; although their occurrence is not symptomatic, they can lead to several clinical problems in patients. Detailed clinical and radiographic assessment and counseling during patient visits is a critical factor in assessing the patient's degree of difficulty to help the dentist for

  19. Comparison of maximum intensity projection and digitally reconstructed radiographic projection for carotid artery stenosis measurement

    International Nuclear Information System (INIS)

    Hyde, Derek E.; Habets, Damiaan F.; Fox, Allan J.; Gulka, Irene; Kalapos, Paul; Lee, Don H.; Pelz, David M.; Holdsworth, David W.

    2007-01-01

    Digital subtraction angiography is being supplanted by three-dimensional imaging techniques in many clinical applications, leading to extensive use of maximum intensity projection (MIP) images to depict volumetric vascular data. The MIP algorithm produces intensity profiles that are different than conventional angiograms, and can also increase the vessel-to-tissue contrast-to-noise ratio. We evaluated the effect of the MIP algorithm in a clinical application where quantitative vessel measurement is important: internal carotid artery stenosis grading. Three-dimensional computed rotational angiography (CRA) was performed on 26 consecutive symptomatic patients to verify an internal carotid artery stenosis originally found using duplex ultrasound. These volumes of data were visualized using two different postprocessing projection techniques: MIP and digitally reconstructed radiographic (DRR) projection. A DRR is a radiographic image simulating a conventional digitally subtracted angiogram, but it is derived computationally from the same CRA dataset as the MIP. By visualizing a single volume with two different projection techniques, the postprocessing effect of the MIP algorithm is isolated. Vessel measurements were made, according to the NASCET guidelines, and percentage stenosis grades were calculated. The paired t-test was used to determine if the measurement difference between the two techniques was statistically significant. The CRA technique provided an isotropic voxel spacing of 0.38 mm. The MIPs and DRRs had a mean signal-difference-to-noise-ratio of 30:1 and 26:1, respectively. Vessel measurements from MIPs were, on average, 0.17 mm larger than those from DRRs (P<0.0001). The NASCET-type stenosis grades tended to be underestimated on average by 2.4% with the MIP algorithm, although this was not statistically significant (P=0.09). The mean interobserver variability (standard deviation) of both the MIP and DRR images was 0.35 mm. It was concluded that the MIP

  20. Measurements of simulated periodontal bone defects in inverted digital image and film-based radiograph: an in vitro study

    International Nuclear Information System (INIS)

    Molon, Rafael Scaf; Morais Camillo, Juliana Aparecida Najarro Dearo; Ferreira, Mauricio Goncalves; Loffredo, Leonor Castro Monteiro; Scaf, Gulnara; Sakakura, Celso Eduardo

    2012-01-01

    This study was performed to compare the inverted digital images and film-based images of dry pig mandibles to measure the periodontal bone defect depth. Forty 2-wall bone defects were made in the proximal region of the premolar in the dry pig mandibles. The digital and conventional radiographs were taken using a Schick sensor and Kodak F-speed intraoral film. Image manipulation (inversion) was performed using Adobe Photoshop 7.0 software. Four trained examiners made all of the radiographic measurements in millimeters a total of three times from the cementoenamel junction to the most apical extension of the bone loss with both types of images: inverted digital and film. The measurements were also made in dry mandibles using a periodontal probe and digital caliper. The Student's t-test was used to compare the depth measurements obtained from the two types of images and direct visual measurement in the dry mandibles. A significance level of 0.05 for a 95% confidence interval was used for each comparison. There was a significant difference between depth measurements in the inverted digital images and direct visual measurements (p>|t|=0.0039), with means of 6.29 mm (IC 95% :6.04-6.54) and 6.79 mm (IC 95% :6.45-7.11), respectively. There was a non-significant difference between the film-based radiographs and direct visual measurements (p>|t|=0.4950), with means of 6.64 mm(IC 95% :6.40-6.89) and 6.79 mm(IC 95% :6.45-7.11), respectively. The periodontal bone defect measurements in the inverted digital images were inferior to film-based radiographs, underestimating the amount of bone loss.

  1. Measurements of simulated periodontal bone defects in inverted digital image and film-based radiograph: an in vitro study

    Energy Technology Data Exchange (ETDEWEB)

    Molon, Rafael Scaf; Morais Camillo, Juliana Aparecida Najarro Dearo; Ferreira, Mauricio Goncalves; Loffredo, Leonor Castro Monteiro; Scaf, Gulnara [Araraquara Dental School, Universidade Estadual Paulista, Sao Paulo (Brazil); Sakakura, Celso Eduardo [Barretos Dental School, Barretos Educational Fundation, Sao Paulo (Brazil)

    2012-09-15

    This study was performed to compare the inverted digital images and film-based images of dry pig mandibles to measure the periodontal bone defect depth. Forty 2-wall bone defects were made in the proximal region of the premolar in the dry pig mandibles. The digital and conventional radiographs were taken using a Schick sensor and Kodak F-speed intraoral film. Image manipulation (inversion) was performed using Adobe Photoshop 7.0 software. Four trained examiners made all of the radiographic measurements in millimeters a total of three times from the cementoenamel junction to the most apical extension of the bone loss with both types of images: inverted digital and film. The measurements were also made in dry mandibles using a periodontal probe and digital caliper. The Student's t-test was used to compare the depth measurements obtained from the two types of images and direct visual measurement in the dry mandibles. A significance level of 0.05 for a 95% confidence interval was used for each comparison. There was a significant difference between depth measurements in the inverted digital images and direct visual measurements (p>|t|=0.0039), with means of 6.29 mm (IC{sub 95%}:6.04-6.54) and 6.79 mm (IC{sub 95%}:6.45-7.11), respectively. There was a non-significant difference between the film-based radiographs and direct visual measurements (p>|t|=0.4950), with means of 6.64 mm(IC{sub 95%}:6.40-6.89) and 6.79 mm(IC{sub 95%}:6.45-7.11), respectively. The periodontal bone defect measurements in the inverted digital images were inferior to film-based radiographs, underestimating the amount of bone loss.

  2. A GaAs pixel detectors-based digital mammographic system: Performances and imaging tests results

    International Nuclear Information System (INIS)

    Annovazzi, A.; Amendolia, S.R.; Bigongiari, A.; Bisogni, M.G.; Catarsi, F.; Cesqui, F.; Cetronio, A.; Colombo, F.; Delogu, P.; Fantacci, M.E.; Gilberti, A.; Lanzieri, C.; Lavagna, S.; Novelli, M.; Passuello, G.; Paternoster, G.; Pieracci, M.; Poletti, M.; Quattrocchi, M.; Rosso, V.; Stefanini, A.; Testa, A.; Venturelli, L.

    2007-01-01

    The prototype presented in this paper is based on GaAs pixel detectors read-out by the PCC/MEDIPIX I circuit. The active area of a sensor is about 1 cm 2 therefore to cover the typical irradiation field used in mammography (18x24 cm 2 ), 18 GaAs detection units have been organized in two staggered rows of nine chips each and moved by a stepper motor in the orthogonal direction. The system is integrated in a mammographic equipment which comprehends the X-ray tube, the bias and data acquisition systems and the PC-based control system. The prototype has been developed in the framework of the Integrated Mammographic Imaging (IMI) project, an industrial research activity aiming to develop innovative instrumentation for morphologic and functional imaging. The project has been supported by the Italian Ministry of Education, University and Research (MIUR) and by five Italian High Tech companies, Alenia Marconi Systems (AMS), CAEN, Gilardoni, LABEN and Poli.Hi.Tech., in collaboration with the universities of Ferrara, Roma 'La Sapienza', Pisa and the Istituto Nazionale di Fisica Nucleare (INFN). In this paper, we report on the electrical characterization and the first imaging test results of the digital mammographic system. To assess the imaging capability of such a detector we have built a phantom, which simulates the breast tissue with malignancies. The radiographs of the phantom, obtained by delivering an entrance dose of 4.8 mGy, have shown particulars with a measured contrast below 1%

  3. A GaAs pixel detectors-based digital mammographic system: Performances and imaging tests results

    Science.gov (United States)

    Annovazzi, A.; Amendolia, S. R.; Bigongiari, A.; Bisogni, M. G.; Catarsi, F.; Cesqui, F.; Cetronio, A.; Colombo, F.; Delogu, P.; Fantacci, M. E.; Gilberti, A.; Lanzieri, C.; Lavagna, S.; Novelli, M.; Passuello, G.; Paternoster, G.; Pieracci, M.; Poletti, M.; Quattrocchi, M.; Rosso, V.; Stefanini, A.; Testa, A.; Venturelli, L.

    2007-06-01

    The prototype presented in this paper is based on GaAs pixel detectors read-out by the PCC/MEDIPIX I circuit. The active area of a sensor is about 1 cm 2 therefore to cover the typical irradiation field used in mammography (18×24 cm 2), 18 GaAs detection units have been organized in two staggered rows of nine chips each and moved by a stepper motor in the orthogonal direction. The system is integrated in a mammographic equipment which comprehends the X-ray tube, the bias and data acquisition systems and the PC-based control system. The prototype has been developed in the framework of the Integrated Mammographic Imaging (IMI) project, an industrial research activity aiming to develop innovative instrumentation for morphologic and functional imaging. The project has been supported by the Italian Ministry of Education, University and Research (MIUR) and by five Italian High Tech companies, Alenia Marconi Systems (AMS), CAEN, Gilardoni, LABEN and Poli.Hi.Tech., in collaboration with the universities of Ferrara, Roma "La Sapienza", Pisa and the Istituto Nazionale di Fisica Nucleare (INFN). In this paper, we report on the electrical characterization and the first imaging test results of the digital mammographic system. To assess the imaging capability of such a detector we have built a phantom, which simulates the breast tissue with malignancies. The radiographs of the phantom, obtained by delivering an entrance dose of 4.8 mGy, have shown particulars with a measured contrast below 1%.

  4. A Comparative Study on Diagnostic Accuracy of Colour Coded Digital Images, Direct Digital Images and Conventional Radiographs for Periapical Lesions – An In Vitro Study

    Science.gov (United States)

    Mubeen; K.R., Vijayalakshmi; Bhuyan, Sanat Kumar; Panigrahi, Rajat G; Priyadarshini, Smita R; Misra, Satyaranjan; Singh, Chandravir

    2014-01-01

    Objectives: The identification and radiographic interpretation of periapical bone lesions is important for accurate diagnosis and treatment. The present study was undertaken to study the feasibility and diagnostic accuracy of colour coded digital radiographs in terms of presence and size of lesion and to compare the diagnostic accuracy of colour coded digital images with direct digital images and conventional radiographs for assessing periapical lesions. Materials and Methods: Sixty human dry cadaver hemimandibles were obtained and periapical lesions were created in first and second premolar teeth at the junction of cancellous and cortical bone using a micromotor handpiece and carbide burs of sizes 2, 4 and 6. After each successive use of round burs, a conventional, RVG and colour coded image was taken for each specimen. All the images were evaluated by three observers. The diagnostic accuracy for each bur and image mode was calculated statistically. Results: Our results showed good interobserver (kappa > 0.61) agreement for the different radiographic techniques and for the different bur sizes. Conventional Radiography outperformed Digital Radiography in diagnosing periapical lesions made with Size two bur. Both were equally diagnostic for lesions made with larger bur sizes. Colour coding method was least accurate among all the techniques. Conclusion: Conventional radiography traditionally forms the backbone in the diagnosis, treatment planning and follow-up of periapical lesions. Direct digital imaging is an efficient technique, in diagnostic sense. Colour coding of digital radiography was feasible but less accurate however, this imaging technique, like any other, needs to be studied continuously with the emphasis on safety of patients and diagnostic quality of images. PMID:25584318

  5. Efficacy study of the digital image processing with varying pixel size at A/D conversion of the chest radiograph

    Energy Technology Data Exchange (ETDEWEB)

    Inamoto, Kazuo; Tanaka, Shinichi; Miura, Takashi; Takahashi, Akira; Iwata, Tetsuya

    1984-12-01

    In the study for development of medical image archiving system, we made experiments in the field of conversion of a X-ray picture to a digital form. Three sets of chest radiograph were selected for the study of digitalization by reading different pixel size (150-300 m) in the method of A/D conversion using a drum scanner and again reconstructed to an analog form after D/A conversion. These copy films of different pixel size were shown and evaluated by 48 volunteer doctors to choose a favorite picture. It did not always follow that the most favorite picture was the finest one using the smallest pixel size. This discrepancy was further analyzed by measurement of a density histogram. By comparison studies of density curves in the same ROI of different pixel size pictures, it was concluded that their choices were dependent on not only fineness but also contrast of an output image after D/A conversion. Often better contrast picture was a key to the selection more than the pixel size. This indicates that digital storing radiographs will be possibly regenerated to the real image by the skillful operation of pixel size and contrast of a radiograph. The results will contribute to the process of recording analog X-ray picture by a digital form in the medical image archiving system.

  6. Aortic stentgraft movement detection using digital roentgen stereophotogrammetric analysis on plane film radiographs - initial results of a phantom study

    International Nuclear Information System (INIS)

    Georg, C.; Welker, V.; Eidam, H.; Alfke, H.

    2005-01-01

    Purpose: To evaluate the feasibility of aortic stentgraft micromovement detection using digital roentgen stereophotogrammetric analysis on plane film radiographs. Material and Methods: An aortic stentgraft used for demonstration purposes was marked with 10 tantalum markers of 0.8 mm in diameter. The stentgraft was placed on a Plexiglas phantom with 5 tantalum markers of 1 mm in diameter simulating a fixed segment needed for mathematical analysis. In a subsequent step, the stentgraft was placed onto an orthopaedic spine model to simulate in vivo conditions in a next step.Two radiographs taken simultaneously from different angles were used for simulating different stentgraft movement, e.g. translation, angulation, aortic pulsation and migration in the spine model. Movement of the stentgraft markers was analysed using a commercially available digital RSA setup (UmRSA registered 4.1, RSA Biomedical, Umea, Sweden). Results: Our study shows the feasibility of measuring aortic stentgraft movement and changes in stentgraft shape in the submillimeter range using digital roentgen stereophotogrammetric analysis. Translation along the 3 cardinal axes, change in stentgraft shape, simulation of aortic pulsation and simulation of in vivo conditions could be described precisely. Conclusion: Aortic stentgraft movement detection using digital roentgen stereophotogrammetric analysis on plane film radiographs is a very promising, precise method. (orig.)

  7. 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

  8. 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.

  9. Variability amongst radiographers in the categorization of clinical acceptability for digital trauma radiography

    Science.gov (United States)

    Decoster, Robin; Toomey, Rachel; Smits, Dirk; Mol, Harrie; Verhelle, Filip; Butler, Marie-Louise

    2016-03-01

    Introduction: Radiographers evaluate anatomical structures to judge clinical acceptability of a radiograph. Whether a radiograph is deemed acceptable for diagnosis or not depends on the individual decision of the radiographer. Individual decisions cause variation in the accepted image quality. To minimise these variations definitions of acceptability, such as in RadLex, were developed. On which criteria radiographers attribute a RadLex categories to radiographs is unknown. Insight into these criteria helps to further optimise definitions and reduce variability in acceptance between radiographers. Therefore, this work aims the evaluation of the correlation between the RadLex classification and the evaluation of anatomical structures, using a Visual Grading Analysis (VGA) Methods: Four radiographers evaluated the visibility of five anatomical structures of 25 lateral cervical spine radiographs on a secondary class display with a VGA. They judged clinical acceptability of each radiograph using RadLex. Relations between VGAS and RadLex category were analysed with Kendall's Tau correlation and Nagelkerke pseudo-R². Results: The overall VGA score (VGAS) and the RadLex score correlate (rτ= 0.62, pscore. The reproduction of spinous processes (rτ=0.67, pscore. Conclusion: RadLex scores and VGAS correlate positively, strongly and significantly. The predictive value of bony structures may support the use of these in the judgement of clinical acceptability. Considerable inter-observer variations in the VGAS within a certain RadLex category, suggest that observers use of observer specific cut-off values.

  10. Development and image quality assessment of a contrast-enhancement algorithm for display of digital chest radiographs

    International Nuclear Information System (INIS)

    Rehm, K.

    1992-01-01

    This dissertation presents a contrast-enhancement algorithm Artifact-Suppressed Adaptive Histogram Equalization (ASAHE). This algorithm was developed as part of a larger effort to replace the film radiographs currently used in radiology departments with digital images. Among the expected benefits of digital radiology are improved image management and greater diagnostic accuracy. Film radiographs record X-ray transmission data at high spatial resolution, and a wide dynamic range of signal. Current digital radiography systems record an image at reduced spatial resolution and with coarse sampling of the available dynamic range. These reductions have a negative impact on diagnostic accuracy. The contrast-enhancement algorithm presented in this dissertation is designed to boost diagnostic accuracy of radiologists using digital images. The ASAHE algorithm is an extension of an earlier technique called Adaptive Histogram Equalization (AHE). The AHE algorithm is unsuitable for chest radiographs because it over-enhances noise, and introduces boundary artifacts. The modifications incorporated in ASAHE suppress the artifacts and allow processing of chest radiographs. This dissertation describes the psychophysical methods used to evaluate the effects of processing algorithms on human observer performance. An experiment conducted with anthropomorphic phantoms and simulated nodules showed the ASAHE algorithm to be superior for human detection of nodules when compared to a computed radiography system's algorithm that is in current use. An experiment conducted using clinical images demonstrating pneumothoraces (partial lung collapse) indicated no difference in human observer accuracy when ASAHE images were compared to computed radiography images, but greater ease of diagnosis when ASAHE images were used. These results provide evidence to suggest that Artifact-Suppressed Adaptive Histogram Equalization can be effective in increasing diagnostic accuracy and efficiency

  11. Digital radiograph of the middle phalanx of the third finger (MP3 region as a tool for skeletal maturity assessment

    Directory of Open Access Journals (Sweden)

    Deepa Y Hegde

    2012-01-01

    Results: The correlation determined between the MP3 stages and cervical vertebrae maturity index (CVMI stages, the peak-wise distribution of the MP3 stages, and the correlation between the MP3 stages and the chronological age were found to be highly significant. Conclusions: Digital radiograph of the MP3 region is definitely a simple, reliable, cost-effective, and time-saving technique for the assessment of skeletal maturity.

  12. 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.

  13. 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.

  14. 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...

  15. 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

  16. 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.

  17. Knee Images Digital Analysis (KIDA): a novel method to quantify individual radiographic features of knee osteoarthritis in detail.

    Science.gov (United States)

    Marijnissen, A C A; Vincken, K L; Vos, P A J M; Saris, D B F; Viergever, M A; Bijlsma, J W J; Bartels, L W; Lafeber, F P J G

    2008-02-01

    Radiography is still the golden standard for imaging features of osteoarthritis (OA), such as joint space narrowing, subchondral sclerosis, and osteophyte formation. Objective assessment, however, remains difficult. The goal of the present study was to evaluate a novel digital method to analyse standard knee radiographs. Standardized radiographs of 20 healthy and 55 OA knees were taken in general practise according to the semi-flexed method by Buckland-Wright. Joint Space Width (JSW), osteophyte area, subchondral bone density, joint angle, and tibial eminence height were measured as continuous variables using newly developed Knee Images Digital Analysis (KIDA) software on a standard PC. Two observers evaluated the radiographs twice, each on two different occasions. The observers were blinded to the source of the radiographs and to their previous measurements. Statistical analysis to compare measurements within and between observers was performed according to Bland and Altman. Correlations between KIDA data and Kellgren & Lawrence (K&L) grade were calculated and data of healthy knees were compared to those of OA knees. Intra- and inter-observer variations for measurement of JSW, subchondral bone density, osteophytes, tibial eminence, and joint angle were small. Significant correlations were found between KIDA parameters and K&L grade. Furthermore, significant differences were found between healthy and OA knees. In addition to JSW measurement, objective evaluation of osteophyte formation and subchondral bone density is possible on standard radiographs. The measured differences between OA and healthy individuals suggest that KIDA allows detection of changes in time, although sensitivity to change has to be demonstrated in long-term follow-up studies.

  18. 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.)

  19. GPU accelerated generation of digitally reconstructed radiographs for 2-D/3-D image registration.

    Science.gov (United States)

    Dorgham, Osama M; Laycock, Stephen D; Fisher, Mark H

    2012-09-01

    Recent advances in programming languages for graphics processing units (GPUs) provide developers with a convenient way of implementing applications which can be executed on the CPU and GPU interchangeably. GPUs are becoming relatively cheap, powerful, and widely available hardware components, which can be used to perform intensive calculations. The last decade of hardware performance developments shows that GPU-based computation is progressing significantly faster than CPU-based computation, particularly if one considers the execution of highly parallelisable algorithms. Future predictions illustrate that this trend is likely to continue. In this paper, we introduce a way of accelerating 2-D/3-D image registration by developing a hybrid system which executes on the CPU and utilizes the GPU for parallelizing the generation of digitally reconstructed radiographs (DRRs). Based on the advancements of the GPU over the CPU, it is timely to exploit the benefits of many-core GPU technology by developing algorithms for DRR generation. Although some previous work has investigated the rendering of DRRs using the GPU, this paper investigates approximations which reduce the computational overhead while still maintaining a quality consistent with that needed for 2-D/3-D registration with sufficient accuracy to be clinically acceptable in certain applications of radiation oncology. Furthermore, by comparing implementations of 2-D/3-D registration on the CPU and GPU, we investigate current performance and propose an optimal framework for PC implementations addressing the rigid registration problem. Using this framework, we are able to render DRR images from a 256×256×133 CT volume in ~24 ms using an NVidia GeForce 8800 GTX and in ~2 ms using NVidia GeForce GTX 580. In addition to applications requiring fast automatic patient setup, these levels of performance suggest image-guided radiation therapy at video frame rates is technically feasible using relatively low cost PC

  20. An image correlation procedure for digitally reconstructed radiographs and electronic portal images

    International Nuclear Information System (INIS)

    Dong, Lei; Boyer, Arthur L.

    1995-01-01

    Purpose: To study a procedure that uses megavoltage digitally reconstructed radiographs (DRRs) calculated from patient's three-dimensional (3D) computed tomography (CT) data as a reference image for correlation with on-line electronic portal images (EPIs) to detect patient setup errors. Methods and Materials: Megavoltage DRRs were generated by ray tracing through a modified volumetric CT data set in which CT numbers were converted into linear attenuation coefficients for the therapeutic beam energy. The DRR transmission image was transformed to the grayscale window of the EPI by a histogram-matching technique. An alternative approach was to calibrate the transmission DRR using a measured response curve of the electronic portal imaging device (EPID). This forces the calculated transmission fluence values to be distributed in the same range as that of the EPID image. A cross-correlation technique was used to determine the degree of alignment of the patient anatomy found in the EPID image relative to the reference DRR. Results: Phantom studies demonstrated that the correlation procedure had a standard deviation of 0.5 mm and 0.5 deg. in aligning translational shifts and in-plane rotations. Systematic errors were found between a reference DRR and a reference EPID image. The automated grayscale image-correlation process was completed within 3 s on a workstation computer or 12 s on a PC. Conclusion: The alignment procedure allows the direct comparison of a patient's treatment portal designed with a 3D planning computer with a patient's on-line portal image acquired at the treatment unit. The image registration process is automated to the extent that it requires minimal user intervention, and it is fast and accurate enough for on-line clinical applications

  1. 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.)

  2. Application of digital tomosynthesis to radiographic diagnosis of the temporal bone. Studies on visualization in normal subjects

    International Nuclear Information System (INIS)

    Kawai, Takashi

    1995-01-01

    To examine the usefulness of digital tomosynthesis for conducting radiographic diagnosis of the temporal bone, visualization of various aural structures such as the semicircular canals, cochlea, vestibular apparatus, ossicles of the ear and facial nerve canal was examined in 18 volunteers. The visualization of temporal bone specimens by digital tomosynthesis and CT images (slice thickness: 1.5 mm) was compared. The results showed that this system (Digital Tomosynthesis) produced clear images of bony labyrinthine structures such as the semicircular canals, cochlea, and vestibular apparatus. Visualization of the ossicles was also clear, and their continuity could be comprehended better than on CT images. This system also provided good visualization of the labyrinthine and tympanic parts of the facial nerve canal, although CT images had greater sharpness. Visualization of the lower half of the mastoid part was poor with this system. (author)

  3. 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.

  4. 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.

  5. A GaAs pixel detectors-based digital mammographic system: Performances and imaging tests results

    Energy Technology Data Exchange (ETDEWEB)

    Annovazzi, A. [LABEN S.p.A., Vimodrone-Milan (Italy); Amendolia, S.R. [Str. Dip. di Matematica e Fisica dell' Universita, Sassari and Sezione I.N.F.N., Pisa (Italy); Bigongiari, A. [CAEN S.p.A., Viareggio-Lucca (Italy); Bisogni, M.G. [Dipartimento di Fisica ' E. Fermi' dell' Universita and Sezione I.N.F.N., Pisa (Italy); Catarsi, F. [CAEN S.p.A., Viareggio-Lucca (Italy); Cesqui, F. [AMS S.p.A, Rome (Italy); Cetronio, A. [AMS S.p.A, Rome (Italy); Colombo, F. [LABEN S.p.A., Vimodrone-Milan (Italy); Delogu, P. [Dipartimento di Fisica ' E. Fermi' dell' Universita and Sezione I.N.F.N., Pisa (Italy); Fantacci, M.E. [Dipartimento di Fisica ' E. Fermi' dell' Universita and Sezione I.N.F.N., Pisa (Italy); Gilberti, A. [LABEN S.p.A., Vimodrone-Milan (Italy); Lanzieri, C. [AMS S.p.A, Rome (Italy); Lavagna, S. [AMS S.p.A, Rome (Italy); Novelli, M. [Dipartimento di Fisica ' E. Fermi' dell' Universita and Sezione I.N.F.N., Pisa (Italy); Passuello, G. [CAEN S.p.A., Viareggio-Lucca (Italy); Paternoster, G. [Dipartimento di Fisica ' E. Fermi' dell' Universita and Sezione I.N.F.N., Pisa (Italy); Pieracci, M. [CAEN S.p.A., Viareggio-Lucca (Italy); Poletti, M. [LABEN S.p.A., Vimodrone-Milan (Italy); Quattrocchi, M. [Dipartimento di Fisica ' E. Fermi' dell' Universita and Sezione I.N.F.N., Pisa (Italy); Rosso, V. [Dipartimento di Fisica ' E. Fermi' dell' Universita and Sezione I.N.F.N., Pisa (Italy); Stefanini, A. [Dipartimento di Fisica ' E. Fermi' dell' Universita and Sezione I.N.F.N., Pisa (Italy)]. E-mail: arnaldo.stefanini@pi.infn.it; Testa, A. [CAEN S.p.A., Viareggio-Lucca (Italy); Venturelli, L. [AMS S.p.A, Rome (Italy)

    2007-06-11

    The prototype presented in this paper is based on GaAs pixel detectors read-out by the PCC/MEDIPIX I circuit. The active area of a sensor is about 1 cm{sup 2} therefore to cover the typical irradiation field used in mammography (18x24 cm{sup 2}), 18 GaAs detection units have been organized in two staggered rows of nine chips each and moved by a stepper motor in the orthogonal direction. The system is integrated in a mammographic equipment which comprehends the X-ray tube, the bias and data acquisition systems and the PC-based control system. The prototype has been developed in the framework of the Integrated Mammographic Imaging (IMI) project, an industrial research activity aiming to develop innovative instrumentation for morphologic and functional imaging. The project has been supported by the Italian Ministry of Education, University and Research (MIUR) and by five Italian High Tech companies, Alenia Marconi Systems (AMS), CAEN, Gilardoni, LABEN and Poli.Hi.Tech., in collaboration with the universities of Ferrara, Roma 'La Sapienza', Pisa and the Istituto Nazionale di Fisica Nucleare (INFN). In this paper, we report on the electrical characterization and the first imaging test results of the digital mammographic system. To assess the imaging capability of such a detector we have built a phantom, which simulates the breast tissue with malignancies. The radiographs of the phantom, obtained by delivering an entrance dose of 4.8 mGy, have shown particulars with a measured contrast below 1%.

  6. 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...

  7. Physical evaluation of prototype high-performance anti-scatter grids: potential for improved digital radiographic image quality

    International Nuclear Information System (INIS)

    Fetterly, Kenneth A; Schueler, Beth A

    2009-01-01

    Grid evaluation for a screen-film x-ray system has typically included independent measurement of the opposing contrast improvement factor and Bucky factor. Neither of these metrics, however, is appropriate when assessing grid performance in a digital imaging environment. For digital radiographic systems, the benefit of an anti-scatter grid is well characterized by the quantum signal-to-noise ratio improvement factor (K SNR ) provided by the grid. The purpose of this work was to measure K SNR of prototype grids designed for use with digital radiographic systems. The prototype grids had 5 mm tall lead septa, fiber interspace material, line rate N = 25 and 36 cm -1 and ratio r = 15 and 21, respectively. The primary and scatter transmission properties of the grids were measured, and K SNR was evaluated over a phantom thickness range of 10-50 cm. To provide a comparison, the K SNR of similarly constructed N44r15 and N80r15 grids is also reported. K SNR of the prototype grids ranged from 1.4 for the 10 cm phantom to 2.4 for the 50 cm phantom. For the thickest phantom, the SNR improvement factor of the prototype grids was 18-83% higher than that of the N44r15 and N80r15 grids, respectively. (note)

  8. Digital subtraction radiographic analysis of the combination of bioabsorbable membrane and bovine morphogenetic protein pool in human periodontal infrabony defects

    Directory of Open Access Journals (Sweden)

    Maria do Carmo Machado Guimarães

    2010-08-01

    Full Text Available OBJECTIVES: This study assessed the bone density gain and its relationship with the periodontal clinical parameters in a case series of a regenerative therapy procedure. MATERIAL AND METHODS: Using a split-mouth study design, 10 pairs of infrabony defects from 15 patients were treated with a pool of bovine bone morphogenetic proteins associated with collagen membrane (test sites or collagen membrane only (control sites. The periodontal healing was clinically and radiographically monitored for six months. Standardized pre-surgical and 6-month postoperative radiographs were digitized for digital subtraction analysis, which showed relative bone density gain in both groups of 0.034 ± 0.423 and 0.105 ± 0.423 in the test and control group, respectively (p>0.05. RESULTS: As regards the area size of bone density change, the influence of the therapy was detected in 2.5 mm² in the test group and 2 mm² in the control group (p>0.05. Additionally, no correlation was observed between the favorable clinical results and the bone density gain measured by digital subtraction radiography (p>0.05. CONCLUSIONS: The findings of this study suggest that the clinical benefit of the regenerative therapy observed did not come with significant bone density gains. Long-term evaluation may lead to a different conclusions.

  9. Feature Extraction of Weld Defectology in Digital Image of Radiographic Film Using Geometric Invariant Moment and Statistical Texture

    International Nuclear Information System (INIS)

    Muhtadan

    2009-01-01

    The purpose of this research is to perform feature extraction in weld defect of digital image of radiographic film using geometric invariant moment and statistical texture method. Feature extraction values can be use as values that used to classify and pattern recognition on interpretation of weld defect in digital image of radiographic film by computer automatically. Weld defectology type that used in this research are longitudinal crack, transversal crack, distributed porosity, clustered porosity, wormhole, and no defect. Research methodology on this research are program development to read digital image, then performing image cropping to localize weld position, and then applying geometric invariant moment and statistical texture formulas to find feature values. The result of this research are feature extraction values that have tested with RST (rotation, scale, transformation) treatment and yield moment values that more invariant there are ϕ 3 , ϕ 4 , ϕ 5 from geometric invariant moment method. Feature values from statistical texture that are average intensity, average contrast, smoothness, 3 rd moment, uniformity, and entropy, they used as feature extraction values. (author)

  10. Radiographic evaluation of marginal bone levels adjacent to parallel-screw cylinder machined-neck implants and rough-surfaced microthreaded implants using digitized panoramic radiographs.

    Science.gov (United States)

    Nickenig, Hans-Joachim; Wichmann, Manfred; Schlegel, Karl Andreas; Nkenke, Emeka; Eitner, Stephan

    2009-06-01

    The purpose of this split-mouth study was to compare macro- and microstructure implant surfaces at the marginal bone level during a stress-free healing period and under functional loading. From January to February 2006, 133 implants (70 rough-surfaced microthreaded implants and 63 machined-neck implants) were inserted in the mandible of 34 patients with Kennedy Class I residual dentitions and followed until February 2008. The marginal bone level was radiographically determined, using digitized panoramic radiographs, at four time points: at implant placement (baseline level), after the healing period, after 6 months of functional loading, and at the end of follow-up. The median follow-up time was 1.9 (range: 1.9-2.1) years. The machined-neck group had a mean crestal bone loss of 0.5 mm (range: 0-2.3) after the healing period, 0.8 mm after 6 months (range: 0-2.4), and 1.1 mm (range: 0-3) at the end of follow-up. The rough-surfaced microthreaded implant group had a mean bone loss of 0.1 mm (range: -0.4-2) after the healing period, 0.4 mm (range: 0-2.1) after 6 months, and 0.5 mm (range: 0-2.1) at the end of follow-up. The two implant types showed significant differences in marginal bone levels (healing period: P=0.01; end of follow-up: Pimplants showed that implants with the microthreaded design caused minimal changes in crestal bone levels during healing (stress-free) and under functional loading.

  11. 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

  12. Dentists' use of digital radiographic techniques: Part I - intraoral X-ray: a questionnaire study of Swedish dentists.

    Science.gov (United States)

    Svenson, Björn; Ståhlnacke, Katri; Karlsson, Reet; Fält, Anna

    2018-03-01

    The present study aims to gain knowledge about the dentist's use and choice of digital intraoral imaging methods. A questionnaire sent to 2481 dentists within the Swedish Dental Society contained questions about the type of X-ray technique used, problems experienced with digital radiography, and reasons for choosing digital technology, and about indications, clinic size and type of service. Response rate was 53%. Ninety-eight percent of the dentists had made the transition to digital radiography; only 2% used film technique, and solid-state detector (SSD) was the most used digital technique. More years in service decreases the likelihood of applying individual indications for performing a full mouth examination. More retakes were done with SSDs compared to storage phosphor plates. Reasons for choosing digital techniques were that work was easier and communication with the patients improved. However, dentists also experienced problems with digital techniques, such as exposure and projection errors and inadequate image quality. The Swedish Radiation Safety Authority states that all radiological examinations should be justified, something not always followed. This study showed that 98% of the respondents, Swedish dentists within the Swedish Dental Society, used digital techniques, and the most used was the solid-state technique.

  13. Semi-automated digital image analysis of patellofemoral joint space width from lateral knee radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Grochowski, S.J. [Mayo Clinic, Department of Orthopedic Surgery, Rochester (United States); Amrami, K.K. [Mayo Clinic, Department of Radiology, Rochester (United States); Kaufman, K. [Mayo Clinic, Department of Orthopedic Surgery, Rochester (United States); Mayo Clinic/Foundation, Biomechanics Laboratory, Department of Orthopedic Surgery, Charlton North L-110L, Rochester (United States)

    2005-10-01

    To design a semi-automated program to measure minimum patellofemoral joint space width (JSW) using standing lateral view radiographs. Lateral patellofemoral knee radiographs were obtained from 35 asymptomatic subjects. The radiographs were analyzed to report both the repeatability of the image analysis program and the reproducibility of JSW measurements within a 2 week period. The results were also compared with manual measurements done by an experienced musculoskeletal radiologist. The image analysis program was shown to have an excellent coefficient of repeatability of 0.18 and 0.23 mm for intra- and inter-observer measurements respectively. The manual method measured a greater minimum JSW than the automated method. Reproducibility between days was comparable to other published results, but was less satisfactory for both manual and semi-automated measurements. The image analysis program had an inter-day coefficient of repeatability of 1.24 mm, which was lower than 1.66 mm for the manual method. A repeatable semi-automated method for measurement of the patellofemoral JSW from radiographs has been developed. The method is more accurate than manual measurements. However, the between-day reproducibility is higher than the intra-day reproducibility. Further investigation of the protocol for obtaining sequential lateral knee radiographs is needed in order to reduce the between-day variability. (orig.)

  14. Development of a Gamma-Ray Detector for Z-Selective Radiographic Imaging

    International Nuclear Information System (INIS)

    Brandis, Michal

    2013-11-01

    Dual-Discrete Energy Gamma-Radiography (DDEGR) is a method for Special Nuclear Materials (SNM) detection. DDEGR utilizes 15.11 and 4.43 MeV gamma-rays produced in the 11B(d,n)12C reaction, in contrast to the conventional use of continuous Bremsstrahlung radiation. The clean and well separated gamma-rays result in high contrast sensitivity, enabling detection of small quantities of SNM. The most important aspects of a DDEGR system were discussed, simulated, measured and demonstrated. An experimental measurement of gamma-ray yields from the 11B(d,n)12C reaction showed that the yields from deuterons with 3{12 MeV energy are 2{201010 N/sr/mC 4.4 MeV gamma- rays and 2{5109 N/sr/mC 15.1 MeV gamma-rays. The measured neutron yields show that the neutron energies extend to 15-23 MeV for the same deuteron energy range. A simplied inspection system was simulated with GEANT4, showing that the ect of scattering on the signal measured in the detector is acceptable. Considering the reaction gamma yields, 1.8 mA deuteron current is required for separation of high-Z materials from medium- and low-Z materials and a 4.5 mA current is required for the additional capability of separating benign high-Z materials from SNM. The main part of the work was development of a detector suitable for a DDEGR system | Time Resolved Event Counting Optical Radiation (TRECOR) detector. TRECOR detector is a novel spectroscopic imaging detector for gamma-rays within the MeV energy range that uses an event counting image intensier with gamma-rays for the rst time. Neutrons that accompany the gamma radiation enable to implement, in parallel, Fast Neutron Resonance Radiography (FNRR), a method for explosives detection. A second generation detector, TRECOR-II, is capable of detecting gamma-rays and neutrons in parallel, separating them to create particle-specic images and energy-specic images for each particle, thus enabling simultaneous implementation of the two detection methods. A full DDEGR laboratory

  15. Benchmarking the performance of fixed-image receptor digital radiographic systems part 1: a novel method for image quality analysis.

    Science.gov (United States)

    Lee, Kam L; Ireland, Timothy A; Bernardo, Michael

    2016-06-01

    This is the first part of a two-part study in benchmarking the performance of fixed digital radiographic general X-ray systems. This paper concentrates on reporting findings related to quantitative analysis techniques used to establish comparative image quality metrics. A systematic technical comparison of the evaluated systems is presented in part two of this study. A novel quantitative image quality analysis method is presented with technical considerations addressed for peer review. The novel method was applied to seven general radiographic systems with four different makes of radiographic image receptor (12 image receptors in total). For the System Modulation Transfer Function (sMTF), the use of grid was found to reduce veiling glare and decrease roll-off. The major contributor in sMTF degradation was found to be focal spot blurring. For the System Normalised Noise Power Spectrum (sNNPS), it was found that all systems examined had similar sNNPS responses. A mathematical model is presented to explain how the use of stationary grid may cause a difference between horizontal and vertical sNNPS responses.

  16. Tuning of the silicon microstrip detector (SCT) digitization parameters at ATLAS

    Energy Technology Data Exchange (ETDEWEB)

    Vishwakarma, Akanksha [Humboldt University, Unter den Linden 6, 10099 Berlin (Germany)

    2016-07-01

    The increased luminosity of LHC in RUN-2 causes high radiation exposure of the ATLAS detector. This might bring about changes in the detector responses, especially of the pixel and the silicon strip detector. To study this, several digitization parameters are varied in the simulation and are analysed by comparing with data. In particular, the impact on the reconstructed cluster and track is considered. This investigation is used to optimize data-Monte Carlo agreement.

  17. Usefulness of computerized method for lung nodule detection on digital chest radiographs using similar subtraction images from different patients

    International Nuclear Information System (INIS)

    Aoki, Takatoshi; Oda, Nobuhiro; Yamashita, Yoshiko; Yamamoto, Keiji; Korogi, Yukunori

    2012-01-01

    Purpose: The purpose of this study is to evaluate the usefulness of a novel computerized method to select automatically the similar chest radiograph for image subtraction in the patients who have no previous chest radiographs and to assist the radiologists’ interpretation by presenting the “similar subtraction image” from different patients. Materials and methods: Institutional review board approval was obtained, and the requirement for informed patient consent was waived. A large database of approximately 15,000 normal chest radiographs was used for searching similar images of different patients. One hundred images of candidates were selected according to two clinical parameters and similarity of the lung field in the target image. We used the correlation value of chest region in the 100 images for searching the most similar image. The similar subtraction images were obtained by subtracting the similar image selected from the target image. Thirty cases with lung nodules and 30 cases without lung nodules were used for an observer performance test. Four attending radiologists and four radiology residents participated in this observer performance test. Results: The AUC for all radiologists increased significantly from 0.925 to 0.974 with the CAD (P = .004). When the computer output images were available, the average AUC for the residents was more improved (0.960 vs. 0.890) than for the attending radiologists (0.987 vs. 0.960). Conclusion: The novel computerized method for lung nodule detection using similar subtraction images from different patients would be useful to detect lung nodules on digital chest radiographs, especially for less experienced readers.

  18. Fractal dimension analysis in digital periapical radiographs: A diagnostic indicator of osteoporosis in post-menopausal women

    Directory of Open Access Journals (Sweden)

    Mathivanan Kavitha

    2017-01-01

    Full Text Available Objectives: To assess the alveolar bone density by fractal dimension (FD analysis in radiovisiograph of postmenopausal women of mandibular posterior region and to correlate FD values with t-scores of quantitative ultrasound of the calcaneus bone. Materials and Methods: This study, approved by the institutional review board, included 40 participants, aged 45–60 years divided into two groups. Twenty postmenopausal women with osteoporosis comprised group 1, and 20 postmenopausal women without osteoporosis comprised group 2 based on bone mineral density assessment of ultrasound of the calcaneus bone. Digital dental radiograph of mandibular first molar were obtained and used for assessing alveolar bone density by FD analysis and were correlated with t-scores of ultrasound of calcaneus bone. Results: The mean FD values were evaluated using SPSS 14 version software, and were found to be 1.738 and 1.867 for group 1 and group 2, respectively, which was statistically significant (P 0.05. Conclusion: FD analysis using direct digital periapical radiographs is a novel method, which can be used for early diagnosis of osteoporosis in the alveolar bone.

  19. Particle identification using digital pulse shape discrimination in a nTD silicon detector with a 1 GHz sampling digitizer

    Science.gov (United States)

    Mahata, K.; Shrivastava, A.; Gore, J. A.; Pandit, S. K.; Parkar, V. V.; Ramachandran, K.; Kumar, A.; Gupta, S.; Patale, P.

    2018-06-01

    In beam test experiments have been carried out for particle identification using digital pulse shape analysis in a 500 μm thick Neutron Transmutation Doped (nTD) silicon detector with an indigenously developed FPGA based 12 bit resolution, 1 GHz sampling digitizer. The nTD Si detector was used in a low-field injection setup to detect light heavy-ions produced in reactions of ∼ 5 MeV/A 7Li and 12C beams on different targets. Pulse height, rise time and current maximum have been obtained from the digitized charge output of a high bandwidth charge and current sensitive pre-amplifier. Good isotopic separation have been achieved using only the digitized charge output in case of light heavy-ions. The setup can be used for charged particle spectroscopy in nuclear reactions involving light heavy-ions around the Coulomb barrier energies.

  20. Potential usefulness of a video printer for producing secondary images from digitized chest radiographs

    Science.gov (United States)

    Nishikawa, Robert M.; MacMahon, Heber; Doi, Kunio; Bosworth, Eric

    1991-05-01

    Communication between radiologists and clinicians could be improved if a secondary image (copy of the original image) accompanied the radiologic report. In addition, the number of lost original radiographs could be decreased, since clinicians would have less need to borrow films. The secondary image should be simple and inexpensive to produce, while providing sufficient image quality for verification of the diagnosis. We are investigating the potential usefulness of a video printer for producing copies of radiographs, i.e. images printed on thermal paper. The video printer we examined (Seikosha model VP-3500) can provide 64 shades of gray. It is capable of recording images up to 1,280 pixels by 1,240 lines and can accept any raster-type video signal. The video printer was characterized in terms of its linearity, contrast, latitude, resolution, and noise properties. The quality of video-printer images was also evaluated in an observer study using portable chest radiographs. We found that observers could confirm up to 90 of the reported findings in the thorax using video- printer images, when the original radiographs were of high quality. The number of verified findings was diminished when high spatial resolution was required (e.g. detection of a subtle pneumothorax) or when a low-contrast finding was located in the mediastinal area or below the diaphragm (e.g. nasogastric tubes).

  1. 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

  2. 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.

  3. Comparison of Response Characteristics of High-Purity Germanium Detectors using Analog Versus Digital Processing

    International Nuclear Information System (INIS)

    Luke, S J; Raschke, K

    2004-01-01

    In this article we will discuss some of the results of the response characteristics of High Purity germanium detectors using analog versus digital processing of the signals that are outputted from the detector. The discussion will focus on whether or not there is a significant difference in the response of the detector with digital electronics that it limits the ability of the detection system to get reasonable gamma ray spectrometric results. Particularly, whether or not the performance of the analysis code Pu600 is compromised

  4. 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)

  5. A novel method for contrast-to-noise ratio (CNR) evaluation of digital mammography detectors

    International Nuclear Information System (INIS)

    Baldelli, P.; Phelan, N.; Egan, G.

    2009-01-01

    The purpose of this study was to test a new, simple method of evaluating the contrast-to-noise ratio (CNR) over the entire image field of a digital detector and to compare different mammography systems. Images were taken under clinical exposure conditions for a range of simulated breast thicknesses using poly(methyl methacrylate) (PMMA). At each PMMA thickness, a second image which included an additional 0.2-mm Al sheet was also acquired. Image processing software was used to calculate the CNR in multiple regions of interest (ROI) covering the entire area of the detector in order to obtain a 'CNR image'. Five detector types were evaluated, two CsI-αSi (GE Healthcare) flat panel systems, one αSe (Hologic) flat panel system and a two generations of scanning photon counting digital detectors (Sectra). Flat panel detectors exhibit better CNR uniformity compared with the first-generation scanning photon counting detector in terms of mean pixel value variation. However, significant improvement in CNR uniformity was observed for the next-generation scanning detector. The method proposed produces a map of the CNR and a measurement of uniformity throughout the entire image field of the detector. The application of this method enables quality control measurement of individual detectors and a comparison of detectors using different technologies. (orig.)

  6. Are digital images good enough? A comparative study of conventional film-screen vs digital radiographs on printed images of total hip replacement

    International Nuclear Information System (INIS)

    Eklund, K.; Jonsson, K.; Lindblom, G.; Lundin, B.; Sanfridsson, J.; Sloth, M.; Sivberg, B.

    2004-01-01

    The aim of this study was to evaluate the inter- and intra-observer variability and to find differences in diagnostic safety between digital and analog technique in diagnostic zones around hip prostheses. In 80 patients who had had a total hip replacement (THR) for more than 2 years, a conventional image and a digital image were taken. Gruen's model of seven distinct regions of interest was used for evaluations. Five experienced radiologists observed the seven regions and noted in a protocol the following distances: stem-cement; cement-bone; and stem-bone. All images were printed on hard copies and were read twice. Weighted kappa, κ w , analyses were used. The two most frequently loosening regions, stem-cement region 1 and cement-bone region 7, were closely analyzed. In region 1 the five observers had an agreement of 86.75-97.92% between analog and digital images in stem-cement, which is a varied κ w 0.29-0.71. For cement-bone region 7 an agreement of 87.21-90.45% was found, which is a varied κ w of 0.48-0.58. All the kappa values differ significantly from nil. The result shows that digital technique is as good as analog radiographs for diagnosing possible loosening of hip prostheses. (orig.)

  7. Are digital images good enough? A comparative study of conventional film-screen vs digital radiographs on printed images of total hip replacement

    Energy Technology Data Exchange (ETDEWEB)

    Eklund, K.; Jonsson, K.; Lindblom, G.; Lundin, B.; Sanfridsson, J.; Sloth, M. [Department of Radiology, Center for Medical Imaging and Physiology, Lund University Hospital, 22185, Lund (Sweden); Sivberg, B. [Department of Nursing, Faculty of Medicine, Lund University, P.O. Box 157, 22100, Lund (Sweden)

    2004-05-01

    The aim of this study was to evaluate the inter- and intra-observer variability and to find differences in diagnostic safety between digital and analog technique in diagnostic zones around hip prostheses. In 80 patients who had had a total hip replacement (THR) for more than 2 years, a conventional image and a digital image were taken. Gruen's model of seven distinct regions of interest was used for evaluations. Five experienced radiologists observed the seven regions and noted in a protocol the following distances: stem-cement; cement-bone; and stem-bone. All images were printed on hard copies and were read twice. Weighted kappa, {kappa}{sub w}, analyses were used. The two most frequently loosening regions, stem-cement region 1 and cement-bone region 7, were closely analyzed. In region 1 the five observers had an agreement of 86.75-97.92% between analog and digital images in stem-cement, which is a varied {kappa}{sub w} 0.29-0.71. For cement-bone region 7 an agreement of 87.21-90.45% was found, which is a varied {kappa}{sub w} of 0.48-0.58. All the kappa values differ significantly from nil. The result shows that digital technique is as good as analog radiographs for diagnosing possible loosening of hip prostheses. (orig.)

  8. Characterization of liquid scintillation detector (BC-501A) and digital pulse shape discrimination (DPSD) system

    Energy Technology Data Exchange (ETDEWEB)

    Lombigit, L., E-mail: lojius@nm.gov.my; Yussup, N., E-mail: nolida@nm.gov.my; Ibrahim, Maslina Mohd; Rahman, Nur Aira Abd; Rawi, M. Z. M. [Instrumentation Group, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia)

    2015-04-29

    A digital n/γ pulse shape discrimination (PSD) system is currently under development at Instrumentation and Automation Centre, Malaysian Nuclear Agency. This system aims at simultaneous detection of fast neutron and gamma ray in mixed radiations environment. This work reports the system characterization performed on the liquid scintillation detector (BC-501A) and digital pulse shape discrimination (DPSD) system. The characterization involves measurement of electron light output from the BC-501A detector and energy channels calibration of the pulse height spectra acquired with DPSD system using set of photon reference sources. The main goal of this experiment is to calibrate the ADC channel of our DPSD system, characterized the BC-501 detector and find the position of Compton edge which later could be used as threshold for the n/γ PSD experiment. The detector resolution however is worse as compared to other published data but it is expected as our detector has a smaller active volume.

  9. Characterization of liquid scintillation detector (BC-501A) and digital pulse shape discrimination (DPSD) system

    International Nuclear Information System (INIS)

    Lombigit, L.; Yussup, N.; Ibrahim, Maslina Mohd; Rahman, Nur Aira Abd; Rawi, M. Z. M.

    2015-01-01

    A digital n/γ pulse shape discrimination (PSD) system is currently under development at Instrumentation and Automation Centre, Malaysian Nuclear Agency. This system aims at simultaneous detection of fast neutron and gamma ray in mixed radiations environment. This work reports the system characterization performed on the liquid scintillation detector (BC-501A) and digital pulse shape discrimination (DPSD) system. The characterization involves measurement of electron light output from the BC-501A detector and energy channels calibration of the pulse height spectra acquired with DPSD system using set of photon reference sources. The main goal of this experiment is to calibrate the ADC channel of our DPSD system, characterized the BC-501 detector and find the position of Compton edge which later could be used as threshold for the n/γ PSD experiment. The detector resolution however is worse as compared to other published data but it is expected as our detector has a smaller active volume

  10. 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.)

  11. LESIONS ASSOCIATED WITH SUBCLINICAL LAMINITIS AND DIGITAL RADIOGRAPHIC EXAM IN HOLSTEIN COWS IN THE TRANSITIONAL PERIOD

    Directory of Open Access Journals (Sweden)

    Antonio Amaral Barbosa

    2016-10-01

    Full Text Available Subclinical laminitis has been responsible for economic losses in dairy industry; thus, its diagnostic    is very important to prevent negative responses to milk production industry. The aim of this study  was to identify lesions associated with subclinical laminitis during the transition period with presence or absence of radiographic signs linked to this disease in Holstein cows. The cows were evaluated during the transition period and categorized into two groups (with and without laminitis according to the lesions associated with this subclinical disease. The radiological dynamic was performed in two target points during the transition period (prepartum and postpartum, with the objective of determining capsular position possible alterations and third phalanx bone degeneration (F3. There was no effect of the presence of lesions associated with subclinical laminitis regarding the position of the third phalanx to the hoof wall (p>0.05. Significant radiographic angular differences (p0.05. Overall, this study did not show radiographic signs of phalangeal misalignment in the hoof of dairy cows with lesions associated with subclinical laminitis during the transition period . Keywords:  aseptic pododermatitis; bovines; complementary exams; hoof.

  12. Analysis of painted arts by energy sensitive radiographic techniques with the Pixel Detector Timepix

    International Nuclear Information System (INIS)

    Zemlicka, J; Jakubek, J; Kroupa, M; Hradil, D; Hradilova, J; Mislerova, H

    2011-01-01

    Non-invasive techniques utilizing X-ray radiation offer a significant advantage in scientific investigations of painted arts and other cultural artefacts such as painted artworks or statues. In addition, there is also great demand for a mobile analytical and real-time imaging device given the fact that many fine arts cannot be transported. The highly sensitive hybrid semiconductor pixel detector, Timepix, is capable of detecting and resolving subtle and low-contrast differences in the inner composition of a wide variety of objects. Moreover, it is able to map the surface distribution of the contained elements. Several transmission and emission techniques are presented which have been proposed and tested for the analysis of painted artworks. This study focuses on the novel techniques of X-ray transmission radiography (conventional and energy sensitive) and X-ray induced fluorescence imaging (XRF) which can be realised at the table-top scale with the state-of-the-art pixel detector Timepix. Transmission radiography analyses the changes in the X-ray beam intensity caused by specific attenuation of different components in the sample. The conventional approach uses all energies from the source spectrum for the creation of the image while the energy sensitive alternative creates images in given energy intervals which enable identification and separation of materials. The XRF setup is based on the detection of characteristic radiation induced by X-ray photons through a pinhole geometry collimator. The XRF method is extremely sensitive to the material composition but it creates only surface maps of the elemental distribution. For the purpose of the analysis several sets of painted layers have been prepared in a restoration laboratory. The composition of these layers corresponds to those of real historical paintings from the 19 th century. An overview of the current status of our methods will be given with respect to the instrumentation and the application in the field of

  13. Analysis of painted arts by energy sensitive radiographic techniques with the Pixel Detector Timepix

    Energy Technology Data Exchange (ETDEWEB)

    Zemlicka, J; Jakubek, J; Kroupa, M [Institute of Experimental and Applied Physics, Czech Technical University Prague, Horska 3a/22, 128 00 Prague 2 (Czech Republic); Hradil, D [Institute of Inorganic Chemistry, AS CR, v.v.i., ALMA, 50 68 Husinec-Oeez (Czech Republic); Hradilova, J; Mislerova, H, E-mail: jan.zemlicka@utef.cvut.cz [Academy of Fine Arts in Prague, ALMA, U Akademie 4, 170 2, Prague 7 (Czech Republic)

    2011-01-15

    Non-invasive techniques utilizing X-ray radiation offer a significant advantage in scientific investigations of painted arts and other cultural artefacts such as painted artworks or statues. In addition, there is also great demand for a mobile analytical and real-time imaging device given the fact that many fine arts cannot be transported. The highly sensitive hybrid semiconductor pixel detector, Timepix, is capable of detecting and resolving subtle and low-contrast differences in the inner composition of a wide variety of objects. Moreover, it is able to map the surface distribution of the contained elements. Several transmission and emission techniques are presented which have been proposed and tested for the analysis of painted artworks. This study focuses on the novel techniques of X-ray transmission radiography (conventional and energy sensitive) and X-ray induced fluorescence imaging (XRF) which can be realised at the table-top scale with the state-of-the-art pixel detector Timepix. Transmission radiography analyses the changes in the X-ray beam intensity caused by specific attenuation of different components in the sample. The conventional approach uses all energies from the source spectrum for the creation of the image while the energy sensitive alternative creates images in given energy intervals which enable identification and separation of materials. The XRF setup is based on the detection of characteristic radiation induced by X-ray photons through a pinhole geometry collimator. The XRF method is extremely sensitive to the material composition but it creates only surface maps of the elemental distribution. For the purpose of the analysis several sets of painted layers have been prepared in a restoration laboratory. The composition of these layers corresponds to those of real historical paintings from the 19{sup th} century. An overview of the current status of our methods will be given with respect to the instrumentation and the application in the field

  14. Digital signal processors for cryogenic high-resolution x-ray detector readout

    International Nuclear Information System (INIS)

    Friedrich, Stephan; Drury, Owen B.; Bechstein, Sylke; Hennig, Wolfgang; Momayezi, Michael

    2003-01-01

    We are developing fast digital signal processors (DSPs) to read out superconducting high-resolution X-ray detectors with on-line pulse processing. For superconducting tunnel junction (STJ) detector read-out, the DSPs offer online filtering, rise time discrimination and pile-up rejection. Compared to analog pulse processing, DSP readout somewhat degrades the detector resolution, but improves the spectral purity of the detector response. We discuss DSP performance with our 9-channel STJ array for synchrotron-based high-resolution X-ray spectroscopy. (author)

  15. Application of digital sampling techniques to particle identification in scintillation detectors

    International Nuclear Information System (INIS)

    Bardelli, L.; Bini, M.; Poggi, G.; Taccetti, N.

    2002-01-01

    In this paper, the use of a fast digitizing system for identification of fast charged particles with scintillation detectors is discussed. The three-layer phoswich detectors developed in the framework of the FIASCO experiment for the detection of light charged particles (LCP) and intermediate mass fragments (IMF) emitted in heavy-ion collisions at Fermi energies are briefly discussed. The standard analog electronics treatment of the signals for particle identification is illustrated. After a description of the digitizer designed to perform a fast digital sampling of the phoswich signals, the feasibility of particle identification on the sampled data is demonstrated. The results obtained with two different pulse shape discrimination analyses based on the digitally sampled data are compared with the standard analog signal treatment. The obtained results suggest, for the present application, the replacement of the analog methods with the digital sampling technique

  16. 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.

  17. Time resolution improvement of Schottky CdTe PET detectors using digital signal processing

    International Nuclear Information System (INIS)

    Nakhostin, M.; Ishii, K.; Kikuchi, Y.; Matsuyama, S.; Yamazaki, H.; Torshabi, A. Esmaili

    2009-01-01

    We present the results of our study on the timing performance of Schottky CdTe PET detectors using the technique of digital signal processing. The coincidence signals between a CdTe detector (15x15x1 mm 3 ) and a fast liquid scintillator detector were digitized by a fast digital oscilloscope and analyzed. In the analysis, digital versions of the elements of timing circuits, including pulse shaper and time discriminator, were created and a digital implementation of the Amplitude and Rise-time Compensation (ARC) mode of timing was performed. Owing to a very fine adjustment of the parameters of timing measurement, a good time resolution of less than 9.9 ns (FWHM) at an energy threshold of 150 keV was achieved. In the next step, a new method of time pickoff for improvement of timing resolution without loss in the detection efficiency of CdTe detectors was examined. In the method, signals from a CdTe detector are grouped by their rise-times and different procedures of time pickoff are applied to the signals of each group. Then, the time pickoffs are synchronized by compensating the fixed time offset, caused by the different time pickoff procedures. This method leads to an improved time resolution of ∼7.2 ns (FWHM) at an energy threshold of as low as 150 keV. The methods presented in this work are computationally fast enough to be used for online processing of data in an actual PET system.

  18. Standard practice for digital imaging and communication in nondestructive evaluation (DICONDE) for digital radiographic (DR) test methods

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice facilitates the interoperability of digital X-ray imaging equipment by specifying image data transfer and archival methods in commonly accepted terms. This document 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 object definitions, information modules and a ...

  19. Evaluation of the detector response function digital conventional radiology; Evaluacion de la funcion de respuesta del detector degital en radiologia convencional. Obtencion de la funcion de referencia

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

    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)

  20. A comparison of periapical radiographs and their digital images for the detection of dental caries

    International Nuclear Information System (INIS)

    Kang, Byung Cheol

    1994-01-01

    In summary, it has been demonstrated by this study that the detection rate of definite large proximal surface caries (C2) on the digital images was good and the detection rate of the first stage caries (C1) was somewhat inferior to film based images. It has been demonstrated by this study and others that the detection of proximal surface caries by present clinical methodologies is still poor. Every effort should be made to develop new means to improve digitizing process.

  1. Digitized hand-wrist radiographs: comparison of subjective and software-derived image quality at various compression ratios.

    Science.gov (United States)

    McCord, Layne K; Scarfe, William C; Naylor, Rachel H; Scheetz, James P; Silveira, Anibal; Gillespie, Kevin R

    2007-05-01

    The objectives of this study were to compare the effect of JPEG 2000 compression of hand-wrist radiographs on observer image quality qualitative assessment and to compare with a software-derived quantitative image quality index. Fifteen hand-wrist radiographs were digitized and saved as TIFF and JPEG 2000 images at 4 levels of compression (20:1, 40:1, 60:1, and 80:1). The images, including rereads, were viewed by 13 orthodontic residents who determined the image quality rating on a scale of 1 to 5. A quantitative analysis was also performed by using a readily available software based on the human visual system (Image Quality Measure Computer Program, version 6.2, Mitre, Bedford, Mass). ANOVA was used to determine the optimal compression level (P quality. When we used quantitative indexes, the JPEG 2000 images had lower quality at all compression ratios compared with the original TIFF images. There was excellent correlation (R2 >0.92) between qualitative and quantitative indexes. Image Quality Measure indexes are more sensitive than subjective image quality assessments in quantifying image degradation with compression. There is potential for this software-based quantitative method in determining the optimal compression ratio for any image without the use of subjective raters.

  2. Computer-aided detection of lung nodules in digital chest radiographs

    International Nuclear Information System (INIS)

    Giger, M.L.; Doi, K.; MacMahon, H.M.

    1986-01-01

    The authors are developing an automated method to detect lung nodules by eliminating the ''camouflaging: effect of the lung background. In order to increase the conspicuity of the nodules, we created, from a single chest radiograph, two images: one in which the signal-to-noise ratio (S/N) of the nodule is maximized and another in which that S/N is suppressed. The difference between these two processed images was subjected to feature-extraction technique in order to isolate the nodules. The detection accuracy of the computer-aided detection scheme, as compared with unaided radiologists' performance, was determined using receiver operating characteristic curve analysis

  3. A BUNCH TO BUCKET PHASE DETECTOR USING DIGITAL RECEIVER TECHNOLOGY

    International Nuclear Information System (INIS)

    DELONG, J.; BRENNAN, J.M.; HAYES, T.; LE, T.N.; SMITH, K.

    2003-01-01

    Transferring high-speed digital signals to a Digital Signal Processor is limited by the IO bandwidth of the DSP. A digital receiver circuit is used to translate high frequency W signals to base-band. The translated output frequency is close to DC and the data rate can be reduced, by decimation, before transfer to the DSP. By translating both the longitudinal beam (bunch) and RF cavity pick-ups (bucket) to DC, a DSP can be used to measure their relative phase angle. The result can be used as an error signal in a beam control servo loop and any phase differences can be compensated

  4. Development of Gas Electron Multiplier(GEM) for digital radiographic system

    International Nuclear Information System (INIS)

    Moon, B. S.; Chung, C. E.; Lee, J. W.

    2000-04-01

    Two computer programs SHOWFIELD and IMAGEQUAL have been developed. SHOWFIELD is used to draw electric field lines for GEM detectors and IMAGEQUAL is used to study the spatial resolution of x-ray images. Various simulation runs have been carried out using EGS4 to study the characteristics of electrons generated by micro-channel plates and Ar, Xe gases. A prototype GEM detector was developed through this project. The GEM detector is composed of a pair of GEM plates, a micro-channel plate, readout circuit in a gas filled chamber. GEM plate were made in CERN to meet KAERI's design specification and the micro-channel plates were purchased from Proxitronic company

  5. Optimization of Dose and Image Quality in Full-fiand Computed Radiography Systems for Common Digital Radiographic Examinations

    Directory of Open Access Journals (Sweden)

    Soo-Foon Moey

    2018-01-01

    Full Text Available IntroductionA fine balance of image quality and radiation dose can be achieved by optimization to minimize stochastic and deterministic effects. This study aimed in ensuring that images of acceptable quality for common radiographic examinations in digital imaging were produced without causing harmful effects. Materials and MethodsThe study was conducted in three phases. The pre-optimization involved ninety physically abled patients aged between 20 to 60 years and weighed between 60 and 80 kilograms for four common digital radiographic examinations. Kerma X_plus, DAP meter was utilized to measure the entrance surface dose (ESD while effective dose (ED was estimated using CALDose_X 5.0 Monte Carlo software. The second phase, an experimental study utilized an anthropomorphic phantom (PBU-50 and Leeds test object TOR CDR for relative comparison of image quality. For the optimization phase, the imaging parameters with acceptable image quality and lowest ESD from the experimental study was related to patient’s body thickness. Image quality were evaluated by two radiologists using the modified evaluation criteria score lists. ResultsSignificant differences were found for image quality for all examinations. However significant difference for ESD were found for PA chest and AP abdomen only. The ESD for three of the examinations were lower than all published data. Additionally, the ESD and ED obtained for all examinations were lower than that recommended by radiation regulatory bodies. ConclusionOptimization of image quality and dose was achieved by utilizing an appropriate tube potential, calibrated automatic exposure control and additional filtration of 0.2mm copper.

  6. Radiologic-anatomic correlation of thoracic vertebrae and rib shadows in chest digital radiograph

    International Nuclear Information System (INIS)

    Yamaguchi, Isao; Itoh, Harumi

    2007-01-01

    The purpose of this study was to provide an introduction to parsing the radiologic appearance of thoracic vertebrae and ribs. In the study, the radiologic-anatomic correlation technique was applied to promote further understanding of normal chest radiographs. The thoracic vertebrae and ribs of chest radiographs were compared with each macroscopic radiologic and computed tomography (CT) image. The rib parsed the linear shadow of the body of the rib. The macroscopic and radiologic images of thoracic vertebrae and ribs were evaluated to explain their normal radiologic findings. The results of such correlation were summarized as follows: The lamina of the vertebral arch was visualized due to anterior rotation of the upper thoracic vertebrae. The density ratio of the thoracic-vertebrae shadow was almost the same in the vertebral body and vertebral arch. The linear shadow superimposed on the rib corresponded to the inferior margin of the rib. The radiologic-anatomic correlation technique was useful to evaluate normal radiologic findings, and the study was useful to radiological technologists. (author)

  7. Changes in jawbones of male patients with chronic renal failure on digital panoramic radiographs.

    Science.gov (United States)

    Dagistan, Saadettin; Miloglu, Ozkan; Caglayan, Fatma

    2016-01-01

    To compare the existence of gonial cortical bone thickness, antegonial index, mandibular canal bone resorption and gonial angle values and pathologies like ground-glass appearance in jawbones and brown tumor in male patients undergoing dialysis due to chronic renal failure and men from the healthy control group on panoramic radiographs. Panoramic radiographs were taken from 80 male individuals in total (40 normal and 40 dialysis patients). Values obtained from the right and left sides of the mandible were summed and their means were calculated. Gonial cortical thickness, antegonial index and gonial angle values were assessed with the Student's t-test, mandibular canal wall resorption with the Chi-square test, and pathologies such as ground-glass appearance and Brown tumor as "available" or "not available." Statistically significant differences were observed among the antegonial index (P chronic renal failure. Although it is not statistically significant, pathology with ground-glass appearance was detected in a patient, but no pathologies like brown tumor were observed. These findings from patients with chronic renal failure must be evaluated in panoramic radiography.

  8. Psychophysical evaluation of the image quality of a dynamic flat-panel digital x-ray image detector using the threshold contrast detail detectability (TCDD) technique

    Science.gov (United States)

    Davies, Andrew G.; Cowen, Arnold R.; Bruijns, Tom J. C.

    1999-05-01

    We are currently in an era of active development of the digital X-ray imaging detectors that will serve the radiological communities in the new millennium. The rigorous comparative physical evaluations of such devices are therefore becoming increasingly important from both the technical and clinical perspectives. The authors have been actively involved in the evaluation of a clinical demonstration version of a flat-panel dynamic digital X-ray image detector (or FDXD). Results of objective physical evaluation of this device have been presented elsewhere at this conference. The imaging performance of FDXD under radiographic exposure conditions have been previously reported, and in this paper a psychophysical evaluation of the FDXD detector operating under continuous fluoroscopic conditions is presented. The evaluation technique employed was the threshold contrast detail detectability (TCDD) technique, which enables image quality to be measured on devices operating in the clinical environment. This approach addresses image quality in the context of both the image acquisition and display processes, and uses human observers to measure performance. The Leeds test objects TO[10] and TO[10+] were used to obtain comparative measurements of performance on the FDXD and two digital spot fluorography (DSF) systems, one utilizing a Plumbicon camera and the other a state of the art CCD camera. Measurements were taken at a range of detector entrance exposure rates, namely 6, 12, 25 and 50 (mu) R/s. In order to facilitate comparisons between the systems, all fluoroscopic image processing such as noise reduction algorithms, were disabled during the experiments. At the highest dose rate FDXD significantly outperformed the DSF comparison systems in the TCDD comparisons. At 25 and 12 (mu) R/s all three-systems performed in an equivalent manner and at the lowest exposure rate FDXD was inferior to the two DSF systems. At standard fluoroscopic exposures, FDXD performed in an equivalent

  9. A Compton suppressed detector multiplicity trigger based digital DAQ for gamma-ray spectroscopy

    Science.gov (United States)

    Das, S.; Samanta, S.; Banik, R.; Bhattacharjee, R.; Basu, K.; Raut, R.; Ghugre, S. S.; Sinha, A. K.; Bhattacharya, S.; Imran, S.; Mukherjee, G.; Bhattacharyya, S.; Goswami, A.; Palit, R.; Tan, H.

    2018-06-01

    The development of a digitizer based pulse processing and data acquisition system for γ-ray spectroscopy with large detector arrays is presented. The system is based on 250 MHz 12-bit digitizers, and is triggered by a user chosen multiplicity of Compton suppressed detectors. The logic for trigger generation is similar to the one practised for analog (NIM/CAMAC) pulse processing electronics, while retaining the fast processing merits of the digitizer system. Codes for reduction of data acquired from the system have also been developed. The system has been tested with offline studies using radioactive sources as well as in the in-beam experiments with an array of Compton suppressed Clover detectors. The results obtained therefrom validate its use in spectroscopic efforts for nuclear structure investigations.

  10. Performance of low-cost X-ray area detectors with consumer digital cameras

    International Nuclear Information System (INIS)

    Panna, A.; Gomella, A.A.; Harmon, K.J.; Chen, P.; Miao, H.; Bennett, E.E.; Wen, H.

    2015-01-01

    We constructed X-ray detectors using consumer-grade digital cameras coupled to commercial X-ray phosphors. Several detector configurations were tested against the Varian PaxScan 3024M (Varian 3024M) digital flat panel detector. These include consumer cameras (Nikon D800, Nikon D700, and Nikon D3X) coupled to a green emission phosphor in a back-lit, normal incidence geometry, and in a front-lit, oblique incidence geometry. We used the photon transfer method to evaluate detector sensitivity and dark noise, and the edge test method to evaluate their spatial resolution. The essential specifications provided by our evaluation include discrete charge events captured per mm 2 per unit exposure surface dose, dark noise in equivalents of charge events per pixel, and spatial resolution in terms of the full width at half maximum (FWHM) of the detector's line spread function (LSF). Measurements were performed using a tungsten anode X-ray tube at 50 kVp. The results show that the home-built detectors provide better sensitivity and lower noise than the commercial flat panel detector, and some have better spatial resolution. The trade-off is substantially smaller imaging areas. Given their much lower costs, these home-built detectors are attractive options for prototype development of low-dose imaging applications

  11. Simulation and Digitization of a Gas Electron Multiplier Detector Using Geant4 and an Object-Oriented Digitization Program

    Science.gov (United States)

    McMullen, Timothy; Liyanage, Nilanga; Xiong, Weizhi; Zhao, Zhiwen

    2017-01-01

    Our research has focused on simulating the response of a Gas Electron Multiplier (GEM) detector using computational methods. GEM detectors provide a cost effective solution for radiation detection in high rate environments. A detailed simulation of GEM detector response to radiation is essential for the successful adaption of these detectors to different applications. Using Geant4 Monte Carlo (GEMC), a wrapper around Geant4 which has been successfully used to simulate the Solenoidal Large Intensity Device (SoLID) at Jefferson Lab, we are developing a simulation of a GEM chamber similar to the detectors currently used in our lab. We are also refining an object-oriented digitization program, which translates energy deposition information from GEMC into electronic readout which resembles the readout from our physical detectors. We have run the simulation with beta particles produced by the simulated decay of a 90Sr source, as well as with a simulated bremsstrahlung spectrum. Comparing the simulation data with real GEM data taken under similar conditions is used to refine the simulation parameters. Comparisons between results from the simulations and results from detector tests will be presented.

  12. A study on the geometric correction for the digital subtraction radiograph

    International Nuclear Information System (INIS)

    Lim, Suk Young; Koh, Kwang Joon

    2001-01-01

    To develop a new subtraction program for registering digital images based on the correspondence of anatomic structures. The digital periapical images were obtained by Digora system with Rinn XCP equipment after translation of 1-16 mm, and rotation of 2-20 at the premolar and molar areas of the human dried mandible. The new subtraction program, NIH Image program and Emago/Advanced program were compared by the peak-signal -to noise ratio (PSNR). The new subtraction program was superior to NIH Images program and Emago/Advanced program up to 16 mm translation and horizontal angulation up to 4. The new subtraction program can be used for subtracting digital periapical images

  13. Comparison between the implementation of quality criteria of radiographic image in conventional and digital mammography equipments

    International Nuclear Information System (INIS)

    Alcantara, M.C.; Sordi, G.M.A.A.; Caldas, L.V.E.; Furquim, T.A.C.

    2008-01-01

    The mammographic examination needs a strict quality control. A publication of the European Commission provides guidelines on quality criteria for the images of the breast, quantifying the quality obtained in the image. Following the recommendations of the European Commission, two kinds of mammographic equipments, at a same institution, were evaluated to compare the quality of the conventional and digital images. Besides of that, the Average Glandular Dose (AGD) and the Entrance Surface Dose (ESD) were measured by using an ionization chamber (Radcal, 6M) in the radiation beams of each equipment. The digital equipment fulfills more quality criteria than the conventional equipment, provided ESD values, AGD values and a rejection index lower than the conventional equipment. Therefore, the digital mammography can be considered more adequate than the conventional one, both for criteria analyses and for dose optimization. (author)

  14. An efficient digital phase sensitive detector for use in electron spin resonance spectroscopy

    International Nuclear Information System (INIS)

    Vistnes, A.I; Wormald, D.I.; Isachsen, S.

    1983-10-01

    A digital sensitive detector for a modified Bruker electron spin resonance spectrometer, equipped with an Aspect 2000 minicomputer, is described. Magnetic field modulation is derived from a clock in the computer, which makes it possible to perform the data acquisition fully synchronously with the modulation. The resulting high phase accuracy makes it possible to compress the data to a single modulation period before the Fourier transformation. Both the in-phase and the phase-quadrature signals (of the first or second harmonic) are recorded simultaneously. The system makes the data processing, including the Fourier transformation, approximately 1000 times faster than previously reported digital phase sensitive detector systems for electron spin resonance spectrometers

  15. Radiographic diagnosis of a rare case of oculo-dento-digital dysplasia

    Directory of Open Access Journals (Sweden)

    Umesh Chandra Parashari

    2011-12-01

    Full Text Available Oculodentodigital dysplasia (ODDD, also known as oculodento-osseous dysplasia, is an extremely rare autosomal dominant disorder with high penetrance, intra- and interfamilial phenotypic variability, and advanced paternal age in sporadic cases. The incidence of this disease is not precisely known, with only 243 cases reported in the scientific literature, suggesting an incidence of around 1 in 10 million people. It is marked mainly by eye abnormalities, craniofacial dysmorphism, dental anomalies, hand and foot malformations, various skeletal defects, and mildly delayed mental development. Neurological changes may appear earlier in each subsequent generation. This case report describes a radiological diagnosis of ODDD based on physical appearance, clinical features and radiographic findings in a 16-year-old girl.

  16. Subjective image quality comparison between two digital dental radiographic systems and conventional dental film

    Directory of Open Access Journals (Sweden)

    Muhammed Ajmal

    2014-10-01

    Recommendations: Improved software and hardware for digital imaging systems are now available and these improvements may now yield images that are comparable in quality to conventional film. However, we recommend that studies still use more observers and other statistical methods to produce ideal results.

  17. X-ray light valve (XLV): a novel detectors' technology for digital mammography

    Science.gov (United States)

    Marcovici, Sorin; Sukhovatkin, Vlad; Oakham, Peter

    2014-03-01

    A novel method, based on X-ray Light Valve (XLV) technology, is proposed for making good image quality yet inexpensive flat panel detectors for digital mammography. The digital mammography markets, particularly in the developing countries, demand quality machines at substantially lower prices than the ones available today. Continuous pressure is applied on x-ray detectors' manufacturers to reduce the flat panel detectors' prices. XLV presents a unique opportunity to achieve the needed price - performance characteristics for direct conversion, x-ray detectors. The XLV based detectors combine the proven, superior, spatial resolution of a-Se with the simplicity and low cost of liquid crystals and optical scanning. The x-ray quanta absorbed by a 200 μm a-Se produce electron - hole pairs that move under an electric field to the top and bottom of a-Se layer. This 2D charge distribution creates at the interface with the liquid crystals a continuous (analog) charge image corresponding to the impinging radiation's information. Under the influence of local electrical charges next to them, the liquid crystals twist proportionally to the charges and vary their light reflectivity. A scanning light source illuminates the liquid crystals while an associated, pixilated photo-detector, having a 42 μm pixel size, captures the light reflected by the liquid crystals and converts it in16 bit words that are transmitted to the machine for image processing and display. The paper will describe a novel XLV, 25 cm x 30 cm, flat panel detector structure and its underlying physics as well as its preliminary performance measured on several engineering prototypes. In particular, the paper will present the results of measuring XLV detectors' DQE, MTF, dynamic range, low contrast resolution and dynamic behavior. Finally, the paper will introduce the new, low cost, XLV detector based, digital mammography machine under development at XLV Diagnostics Inc.

  18. Plastic scintillation detectors for dose monitoring in digital breast tomosynthesis

    Science.gov (United States)

    Antunes, J.; Machado, J.; Peralta, L.; Matela, N.

    2018-01-01

    Plastic scintillators detectors (PSDs) have been studied as dosimeters, since they provide a cost-effective alternative to conventional ionization chambers. Measurement and analysis of energy dependency were performed on a Siemens Mammomat tomograph for two different peak kilovoltages: 26 kV and 35 kV. Both PSD displayed good linearity for each energy considered and almost no energy dependence.

  19. Characterizing X-ray detectors for prototype digital breast tomosynthesis systems

    International Nuclear Information System (INIS)

    Kim, Y.-S.; Park, H.-S.; Park, S.-J.; Choi, S.; Lee, H.; Kim, H.-J.; Lee, D.; Choi, Y.-W.

    2016-01-01

    The digital breast tomosynthesis (DBT) system is a newly developed 3-D imaging technique that overcomes the tissue superposition problems of conventional mammography. Therefore, it produces fewer false positives. In DBT system, several parameters are involved in image acquisition, including geometric components. A series of projections should be acquired at low exposure. This makes the system strongly dependent on the detector's characteristic performance. This study compares two types of x-ray detectors developed by the Korea Electrotechnology Research Institute (KERI). The first prototype DBT system has a CsI (Tl) scintillator/CMOS based flat panel digital detector (2923 MAM, Dexela Ltd.), with a pixel size of 0.0748 mm. The second uses a-Se based direct conversion full field detector (AXS 2430, analogic) with a pixel size of 0.085 mm. The geometry of both systems is same, with a focal spot 665.8 mm from the detector, and a center of rotation 33 mm above the detector surface. The systems were compared with regard to modulation transfer function (MTF), normalized noise power spectrum (NNPS), detective quantum efficiency (DQE) and a new metric, the relative object detectability (ROD). The ROD quantifies the relative performance of each detector at detecting specified objects. The system response function demonstrated excellent linearity (R 2 >0.99). The CMOS-based detector had a high sensitivity, while the Anrad detector had a large dynamic range. The higher MTF and noise power spectrum (NPS) values were measured using an Anrad detector. The maximum DQE value of the Dexela detector was higher than that of the Anrad detector with a low exposure level, considering one projection exposure for tomosynthesis. Overall, the Dexela detector performed better than did the Anrad detector with regard to the simulated Al wires, spheres, test objects of ROD with low exposure level. In this study, we compared the newly developed prototype DBT system with two different types

  20. [Industrial production of the LDRD "Siberia-N" digital radiographic devices].

    Science.gov (United States)

    Baru, S E; Ukraintsev, Iu G

    2004-01-01

    It is envisaged, as a key task, in the Federal Program on Tuberculosis Monitoring, that preventive measures and early TB detection is a priority. Fluorography, which is important for the recognition of pulmonary tuberculosis at its early stages, has been used in the diagnostics of pulmonary pathologies. However, according to the statistics provided by the Russian Ministry of Healthcare, around 80% of available medical equipment is now worn and obsolete. Owing to a fruitful research activity related with designing a digital low-dose X-Ray unit (Siberia-N) carried out by the Budker Institute of Nuclear Physics, Siberian Branch of the Russian Academy of Sciences (Novosibirsk), a certain progress can be stated in perfecting the fluorography equipment in Russia. The above unit incorporates all advanced achievements in the field of digital X-Ray diagnostics.

  1. Digital front-end electronics for COMPASS Muon-Wall 1 detector

    International Nuclear Information System (INIS)

    Alekseev, G.D.; Zhuravlev, N.I.; Maggiora, A.

    2005-01-01

    The digital front-end electronics for the COMPASS Muon-Wall 1 (CERN) detector is described. The digital card has been designed on the basis of the TDC chip F1. One card includes 6 F1 chips (192 channels), bus arbiter, DAC, power supply distribution, hot-link interface. The total number of the digital cards in the system is 44 housed in 5 euro-crates (6U), the total number of readout channels is 8448. The electronics has been designed by the Dzhelepov Laboratory of Nuclear Problems (JINR) and INFN (Torino, Italy) experts

  2. A Computer- Based Digital Signal Processing for Nuclear Scintillator Detectors

    International Nuclear Information System (INIS)

    Ashour, M.A.; Abo Shosha, A.M.

    2000-01-01

    In this paper, a Digital Signal Processing (DSP) Computer-based system for the nuclear scintillation signals with exponential decay is presented. The main objective of this work is to identify the characteristics of the acquired signals smoothly, this can be done by transferring the signal environment from random signal domain to deterministic domain using digital manipulation techniques. The proposed system consists of two major parts. The first part is the high performance data acquisition system (DAQ) that depends on a multi-channel Logic Scope. Which is interfaced with the host computer through the General Purpose Interface Board (GPIB) Ver. IEEE 488.2. Also, a Graphical User Interface (GUI) has been designed for this purpose using the graphical programming facilities. The second of the system is the DSP software Algorithm which analyses, demonstrates, monitoring these data to obtain the main characteristics of the acquired signals; the amplitude, the pulse count, the pulse width, decay factor, and the arrival time

  3. The digital radiographic and computed tomography imaging of two types of explosive devices

    International Nuclear Information System (INIS)

    Galiano Riveros, Eduardo

    2002-01-01

    Two well-established medical imaging methods, digital radiography (DR) and computed tomography (CT), were employed to obtain images of two types of explosive devices, model rocket engines and shotgun shells. The images were evaluated from an airport security perspective. In terms of geometrical shape, the detection probability of the explosive devices appears to be higher with DR imaging, but in terms of the actual explosive compounds in the devices, CT appears to offer a higher detection probability. DR imaging offers a low detection probability for the explosive powder in the shotgun shells, but a rather significant detection probability for the explosive propellant in the model rocket engines

  4. Pneumothorax size measurements on digital chest radiographs: Intra- and inter- rater reliability.

    Science.gov (United States)

    Thelle, Andreas; Gjerdevik, Miriam; Grydeland, Thomas; Skorge, Trude D; Wentzel-Larsen, Tore; Bakke, Per S

    2015-10-01

    Detailed and reliable methods may be important for discussions on the importance of pneumothorax size in clinical decision-making. Rhea's method is widely used to estimate pneumothorax size in percent based on chest X-rays (CXRs) from three measure points. Choi's addendum is used for anterioposterior projections. The aim of this study was to examine the intrarater and interrater reliability of the Rhea and Choi method using digital CXR in the ward based PACS monitors. Three physicians examined a retrospective series of 80 digital CXRs showing pneumothorax, using Rhea and Choi's method, then repeated in a random order two weeks later. We used the analysis of variance technique by Eliasziw et al. to assess the intrarater and interrater reliability in altogether 480 estimations of pneumothorax size. Estimated pneumothorax sizes ranged between 5% and 100%. The intrarater reliability coefficient was 0.98 (95% one-sided lower-limit confidence interval C 0.96), and the interrater reliability coefficient was 0.95 (95% one-sided lower-limit confidence interval 0.93). This study has shown that the Rhea and Choi method for calculating pneumothorax size has high intrarater and interrater reliability. These results are valid across gender, side of pneumothorax and whether the patient is diagnosed with primary or secondary pneumothorax. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  5. Evaluation of a flat panel digital radiographic system for low-dose portable imaging of neonates

    International Nuclear Information System (INIS)

    Samei, Ehsan; Hill, Jeanne G.; Frey, G. Donald; Southgate, W. Michael; Mah, Eugene; Delong, David

    2003-01-01

    The purpose of this study was to evaluate the clinical utility of an investigational flat-panel digital radiography system for low-dose portable neonatal imaging. Thirty image-pairs from neonatal intensive care unit patients were acquired with a commercial Computed Radiography system (Agfa, ADC 70), and with the investigational system (Varian, Paxscan 2520) at one-quarter of the exposure. The images were evaluated for conspicuity and localization of the endings of ancillary catheters and tubes in two observer performance experiments with three pediatric radiologists and three neonatologists serving as observers. The results indicated no statistically significant difference in diagnostic quality between the images from the investigational system and from CR. Given the investigational system's superior resolution and noise characteristics, observer results suggest that the high detective quantum efficiency of flat-panel digital radiography systems can be utilized to decrease the radiation dose/exposure to neonatal patients, although post-processing of the images remains to be optimized. The rapid availability of flat-panel images in portable imaging was found to be an added advantage for timely clinical decision-making

  6. Digital mammography; Mamografia digital

    Energy Technology Data Exchange (ETDEWEB)

    Chevalier, M.; Torres, R.

    2010-07-01

    Mammography represents one of the most demanding radiographic applications, simultaneously requiring excellent contrast sensitivity, high spatial resolution, and wide dynamic range. Film/screen is the most widely extended image receptor in mammography due to both its high spatial resolution and contrast. The film/screen limitations are related with its narrow latitude, structural noise and that is at the same time the medium for the image acquisition, storage and presentation. Several digital detector made with different technologies can overcome these difficulties. Here, these technologies as well as their main advantages and disadvantages are analyzed. Also it is discussed its impact on the mammography examinations, mainly on the breast screening programs. (Author).

  7. Application of neural networks to digital pulse shape analysis for an array of silicon strip detectors

    Energy Technology Data Exchange (ETDEWEB)

    Flores, J.L. [Dpto de Ingeniería Eléctrica y Térmica, Universidad de Huelva (Spain); Martel, I. [Dpto de Física Aplicada, Universidad de Huelva (Spain); CERN, ISOLDE, CH 1211 Geneva, 23 (Switzerland); Jiménez, R. [Dpto de Ingeniería Electrónica, Sist. Informáticos y Automática, Universidad de Huelva (Spain); Galán, J., E-mail: jgalan@diesia.uhu.es [Dpto de Ingeniería Electrónica, Sist. Informáticos y Automática, Universidad de Huelva (Spain); Salmerón, P. [Dpto de Ingeniería Eléctrica y Térmica, Universidad de Huelva (Spain)

    2016-09-11

    The new generation of nuclear physics detectors that used to study nuclear reactions is considering the use of digital pulse shape analysis techniques (DPSA) to obtain the (A,Z) values of the reaction products impinging in solid state detectors. This technique can be an important tool for selecting the relevant reaction channels at the HYDE (HYbrid DEtector ball array) silicon array foreseen for the Low Energy Branch of the FAIR facility (Darmstadt, Germany). In this work we study the feasibility of using artificial neural networks (ANNs) for particle identification with silicon detectors. Multilayer Perceptron networks were trained and tested with recent experimental data, showing excellent identification capabilities with signals of several isotopes ranging from {sup 12}C up to {sup 84}Kr, yielding higher discrimination rates than any other previously reported.

  8. Magnetic Resonance-Based Treatment Planning for Prostate Intensity-Modulated Radiotherapy: Creation of Digitally Reconstructed Radiographs

    International Nuclear Information System (INIS)

    Chen, Lili; Nguyen, Thai-Binh; Jones, Elan; Chen Zuoqun; Luo Wei; Wang Lu; Price, Robert A.; Pollack, Alan; Ma, C.-M. Charlie

    2007-01-01

    Purpose: To develop a technique to create magnetic resonance (MR)-based digitally reconstructed radiographs (DRR) for initial patient setup for routine clinical applications of MR-based treatment planning for prostate intensity-modulated radiotherapy. Methods and Materials: Twenty prostate cancer patients' computed tomography (CT) and MR images were used for the study. Computed tomography and MR images were fused. The pelvic bony structures, including femoral heads, pubic rami, ischium, and ischial tuberosity, that are relevant for routine clinical patient setup were manually contoured on axial MR images. The contoured bony structures were then assigned a bulk density of 2.0 g/cm 3 . The MR-based DRRs were generated. The accuracy of the MR-based DDRs was quantitatively evaluated by comparing MR-based DRRs with CT-based DRRs for these patients. For each patient, eight measuring points on both coronal and sagittal DRRs were used for quantitative evaluation. Results: The maximum difference in the mean values of these measurement points was 1.3 ± 1.6 mm, and the maximum difference in absolute positions was within 3 mm for the 20 patients investigated. Conclusions: Magnetic resonance-based DRRs are comparable to CT-based DRRs for prostate intensity-modulated radiotherapy and can be used for patient treatment setup when MR-based treatment planning is applied clinically

  9. Comparison of two immobilization techniques using portal film and digitally reconstructed radiographs for pediatric patients with brain tumors

    International Nuclear Information System (INIS)

    Zhu Yunping; Stovall, John; Butler, Laura; Ji Qing; Gaber, M. Waleed; Samant, Sanjiv; Sontag, Marc R.; Armendi, Alberto J. de; Merchant, Thomas E.

    2000-01-01

    Purpose: To compare the accuracy of two immobilization techniques for pediatric brain tumor patients. Methods and Materials: We analyzed data from 128 treatments involving 22 patients. Patients were immobilized with either a relocatable head frame (12 patients) or a vacuum bag (10 patients). Orthogonal portal films were used as verification images. Errors in patient positioning were measured by comparing verification images with digitally reconstructed radiographs generated by a three-dimensional treatment-planning system. Results: With the head frame, systematic errors ranged from 1.4 mm to 2.1 mm; random errors, from 1.7 mm to 2.1 mm. With the vacuum bag, systematic errors ranged from 2.1 mm to 2.5 mm; random errors, from 2.0 mm to 2.6 mm. For the head frame, the mean length of the radial displacement was 4.4 mm; 90% of the total three-dimensional deviation was less than 6.8 mm. The corresponding values for the vacuum bag were 5.0 and 6.6 mm, respectively. Conclusions: The head frame and vacuum bag techniques limit the random and systematic errors in each of the three directions to within ± 5 mm. We have used these results to determine the margin used to create the planning target volume for conformal radiation therapy

  10. Correlation between the physical performances measured from detectors and the diagnostic image quality in digital mammography

    International Nuclear Information System (INIS)

    Perez-Ponce, H.

    2009-05-01

    In digital mammography two approaches exist to estimate image quality. In the first approach, human observer assesses the lesion detection in mammograms. Unfortunately, such quality assessment is subject to interobserver variability, and requires a large amount of time and human resources. In the second approach, objective and human-independent parameters relating to image spatial resolution and noise (MTF and NPS) are used to evaluate digital detector performance; even if these parameters are objective, they are not directly related to lesion detection. A method leading to image quality assessment which is both human independent, and directly related to lesion detection is very important for the optimal use of mammographic units. This Ph.D thesis presents the steps towards such a method: the computation of realistic virtual images using an 'X ray source/digital detector' model taking into account the physical parameters of the detector (spatial resolution and noise measurements) measured under clinical conditions. From results obtained in this work, we have contributed to establish the link between the physical characteristics of detectors and the clinical quality of the image for usual exposition conditions. Furthermore, we suggest the use of our model for the creation of virtual images, in order to rapidly determine the optimal conditions in mammography, which usually is a long and tedious experimental process. This is an essential aspect to be taken into account for radioprotection of patients, especially in the context of organized mass screening of breast cancer. (author)

  11. Digital column readout architectures for hybrid pixel detector readout chips

    International Nuclear Information System (INIS)

    Poikela, T; Plosila, J; Westerlund, T; Buytaert, J; Campbell, M; Gaspari, M De; Llopart, X; Wyllie, K; Gromov, V; Kluit, R; Beuzekom, M van; Zappon, F; Zivkovic, V; Brezina, C; Desch, K; Fu, Y; Kruth, A

    2014-01-01

    In this paper, two digital column architectures suitable for sparse readout of data from a pixel matrix in trigger-less applications are presented. Each architecture reads out a pixel matrix of 256 x 256 pixels with a pixel pitch of 55 μm. The first architecture has been implemented in the Timepix3 chip, and this is presented together with initial measurements. Simulation results and measured data are compared. The second architecture has been designed for Velopix, a readout chip planned for the LHCb VELO upgrade. Unlike Timepix3, this has to be tolerant to radiation-induced single-event effects. Results from post-layout simulations are shown with the circuit architectures

  12. Optimum image compression rate maintaining diagnostic image quality of digital intraoral radiographs

    International Nuclear Information System (INIS)

    Song, Ju Seop; Koh, Kwang Joon

    2000-01-01

    The aims of the present study are to determine the optimum compression rate in terms of file size reduction and diagnostic quality of the images after compression and evaluate the transmission speed of original or each compressed images. The material consisted of 24 extracted human premolars and molars. The occlusal surfaces and proximal surfaces of the teeth had a clinical disease spectrum that ranged from sound to varying degrees of fissure discoloration and cavitation. The images from Digora system were exported in TIFF and the images from conventional intraoral film were scanned and digitalized in TIFF by Nikon SF-200 scanner(Nikon, Japan). And six compression factors were chosen and applied on the basis of the results from a pilot study. The total number of images to be assessed were 336. Three radiologists assessed the occlusal and proximal surfaces of the teeth with 5-rank scale. Finally diagnosed as either sound or carious lesion by one expert oral pathologist. And sensitivity and specificity and kappa value for diagnostic agreement was calculated. Also the area (Az) values under the ROC curve were calculated and paired t-test and oneway ANOVA test was performed. Thereafter, transmission time of the image files of the each compression level were compared with that of the original image files. No significant difference was found between original and the corresponding images up to 7% (1:14) compression ratio for both the occlusal and proximal caries (p<0.05). JPEG3 (1:14) image files are transmitted fast more than 10 times, maintained diagnostic information in image, compared with original image files. 1:14 compressed image file may be used instead of the original image and reduce storage needs and transmission time.

  13. Fundamental imaging characteristics of a slot-scan digital chest radiographic system

    International Nuclear Information System (INIS)

    Samei, Ehsan; Saunders, Robert S.; Lo, Joseph Y.; Dobbins, James T. III; Jesneck, Jonathan L.; Floyd, Carey E.; Ravin, Carl E.

    2004-01-01

    Our purpose in this study was to evaluate the fundamental image quality characteristics of a new slot-scan digital chest radiography system (ThoraScan, Delft Imaging Systems/Nucletron, Veenendaal, The Netherlands). The linearity of the system was measured over a wide exposure range at 90, 117, and 140 kVp with added Al filtration. System uniformity and reproducibility were established with an analysis of images from repeated exposures. The modulation transfer function (MTF) was evaluated using an established edge method. The noise power spectrum (NPS) and the detective quantum efficiency (DQE) of the system were evaluated at the three kilo-voltages over a range of exposures. Scatter fraction (SF) measurements were made using a posterior beam stop method and a geometrical chest phantom. The system demonstrated excellent linearity, but some structured nonuniformities. The 0.1 MTF values occurred between 3.3-3.5 mm -1 . The DQE(0.15) and DQE(2.5) were 0.21 and 0.07 at 90 kVp, 0.18 and 0.05 at 117 kVp, and 0.16 and 0.03 at 140 kVp, respectively. The system exhibited remarkably lower SFs compared to conventional full-field systems with anti-scatter grid, measuring 0.13 in the lungs and 0.43 in the mediastinum. The findings indicated that the slot-scan design provides marked scatter reduction leading to high effective DQE (DQE eff ) of the system and reduced patient dose required to achieve high image quality

  14. DQE of wireless digital detectors: Comparative performance with differing filtration schemes

    International Nuclear Information System (INIS)

    Samei, Ehsan; Murphy, Simon; Christianson, Olav

    2013-01-01

    Purpose: Wireless flat panel detectors are gaining increased usage in portable medical imaging. Two such detectors were evaluated and compared with a conventional flat-panel detector using the formalism of the International Electrotechnical Commission (IEC 62220-1) for measuring modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE) using two different filtration schemes.Methods: Raw images were acquired for three image receptors (DRX-1C and DRX-1, Carestream Health; Inc., Pixium 4600, Trixell) using a radiographic system with a well-characterized output (Philips Super80 CP, Philips Healthcare). Free in-air exposures were measured using a calibrated radiation meter (Unfors Mult-O-Meter Type 407, Unfors Instruments AB). Additional aluminum filtration and a new alternative combined copper-aluminum filtration were used to conform the x ray output to IEC-specified beam quality definitions RQA5 and RQA9. Using the IEC 62220-1 formalism, each detector was evaluated at X N /2, X N , and 2X N , where the normal exposure level to the detector surface (X N ) was set to 8.73 μGy (1.0 mR). The prescribed edge test device was used to evaluate the MTF, while the NNPS was measured using uniform images. The DQE was then calculated from the MTF and NNPS and compared across detectors, exposures, and filtration schemes.Results: The three DR systems had largely comparable MTFs with DRX-1 demonstrating lower values above 1.0 cycles/mm. At each exposure, DRX-1C and Pixium detectors demonstrated better noise performance than that of DRX-1. Zero-frequency DQEs for DRX-1C, Pixium, and DRX-1 detectors were approximately 74%, 63%, and 38% for RQA5 and 50%, 42%, and 28% for RQA9, respectively.Conclusions: DRX-1C detector exhibited superior DQE performance compared to Pixium and DRX-1. In terms of filtration, the alternative filtration was found to provide comparable performance in terms of rank ordering of different detectors with

  15. DQE of wireless digital detectors: Comparative performance with differing filtration schemes

    Energy Technology Data Exchange (ETDEWEB)

    Samei, Ehsan [Carl E. Ravin Advanced Imaging Laboratories, Departments of Radiology, Biomedical Engineering, Physics, and Electrical and Computer Engineering, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27705 (United States); Murphy, Simon; Christianson, Olav [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States)

    2013-08-15

    Purpose: Wireless flat panel detectors are gaining increased usage in portable medical imaging. Two such detectors were evaluated and compared with a conventional flat-panel detector using the formalism of the International Electrotechnical Commission (IEC 62220-1) for measuring modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE) using two different filtration schemes.Methods: Raw images were acquired for three image receptors (DRX-1C and DRX-1, Carestream Health; Inc., Pixium 4600, Trixell) using a radiographic system with a well-characterized output (Philips Super80 CP, Philips Healthcare). Free in-air exposures were measured using a calibrated radiation meter (Unfors Mult-O-Meter Type 407, Unfors Instruments AB). Additional aluminum filtration and a new alternative combined copper-aluminum filtration were used to conform the x ray output to IEC-specified beam quality definitions RQA5 and RQA9. Using the IEC 62220-1 formalism, each detector was evaluated at X{sub N}/2, X{sub N}, and 2X{sub N}, where the normal exposure level to the detector surface (X{sub N}) was set to 8.73 μGy (1.0 mR). The prescribed edge test device was used to evaluate the MTF, while the NNPS was measured using uniform images. The DQE was then calculated from the MTF and NNPS and compared across detectors, exposures, and filtration schemes.Results: The three DR systems had largely comparable MTFs with DRX-1 demonstrating lower values above 1.0 cycles/mm. At each exposure, DRX-1C and Pixium detectors demonstrated better noise performance than that of DRX-1. Zero-frequency DQEs for DRX-1C, Pixium, and DRX-1 detectors were approximately 74%, 63%, and 38% for RQA5 and 50%, 42%, and 28% for RQA9, respectively.Conclusions: DRX-1C detector exhibited superior DQE performance compared to Pixium and DRX-1. In terms of filtration, the alternative filtration was found to provide comparable performance in terms of rank ordering of different

  16. Evaluation of real-time digital pulse shapers with various HPGe and silicon radiation detectors

    International Nuclear Information System (INIS)

    Menaa, N.; D'Agostino, P.; Zakrzewski, B.; Jordanov, V.T.

    2011-01-01

    Real-time digital pulse shaping techniques allow synthesis of pulse shapes that have been difficult to realize using the traditional analog methods. Using real-time digital shapers, triangular/trapezoidal filters can be synthesized in real time. These filters exhibit digital control on the rise time, fall time, and flat-top of the trapezoidal shape. Thus, the trapezoidal shape can be adjusted for optimum performance at different distributions of the series and parallel noise. The trapezoidal weighting function (WF) represents the optimum time-limited pulse shape when only parallel and series noises are present in the detector system. In the presence of 1/F noise, the optimum WF changes depending on the 1/F noise contribution. In this paper, we report on the results of the evaluation of new filter types for processing signals from CANBERRA high purity germanium (HPGe) and passivated, implanted, planar silicon (PIPS) detectors. The objective of the evaluation is to determine improvements in performance over the current trapezoidal (digital) filter. The evaluation is performed using a customized CANBERRA digital signal processing unit that is fitted with new FPGA designs and any required firmware modifications to support operation of the new filters. The evaluated filters include the Cusp, one-over-F (1/F), and pseudo-Gaussian filters. The results are compared with the CANBERRA trapezoidal shaper.

  17. Digital signal processing for CdTe detectors using VXIbus data collection systems

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Daiji; Takahashi, Hiroyuki; Kurahashi, Tomohiko; Iguchi, Tetsuo; Nakazawa, Masaharu

    1996-07-01

    Recently fast signal digitizing technique has been developed, and signal waveforms with very short time periods can be obtained. In this paper, we analyzed each measured pulse which was digitized by an apparatus of this kind, and tried to improve an energy resolution of a CdTe semiconductor detector. The result of the energy resolution for {sup 137}Cs 662 keV photopeak was 13 keV. Also, we developed a fast data collection system based on VXIbus standard, and the counting rate on this system was obtained about 50 counts per second. (author)

  18. Digital Data Acquisition System for experiments with segmented detectors at National Superconducting Cyclotron Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Starosta, K., E-mail: starosta@sfu.c [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Vaman, C.; Miller, D.; Voss, P.; Bazin, D.; Glasmacher, T. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Crawford, H.; Mantica, P. [National Superconducting Cyclotron Laboratory and Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Tan, H.; Hennig, W.; Walby, M.; Fallu-Labruyere, A.; Harris, J.; Breus, D.; Grudberg, P.; Warburton, W.K. [XIA LLC, Hayward, CA 94544 (United States)

    2009-11-11

    A 624-channel Digital Data Acquisition System capable of instrumenting the Segmented Germanium Array at National Superconducting Cyclotron Laboratory has been implemented using Pixie-16 Digital Gamma Finder modules by XIA LLC. The system opens an opportunity for determination of the first interaction position of a gamma ray in a SeGA detector from implementation of gamma-ray tracking. This will translate into a significantly improved determination of angle of emission, and in consequence much better Doppler corrections for experiments with fast beams. For stopped-beam experiments the system provides means for zero dead time measurements of rare decays, which occur on time scales of microseconds.

  19. Digital Data Acquisition System for experiments with segmented detectors at National Superconducting Cyclotron Laboratory

    International Nuclear Information System (INIS)

    Starosta, K.; Vaman, C.; Miller, D.; Voss, P.; Bazin, D.; Glasmacher, T.; Crawford, H.; Mantica, P.; Tan, H.; Hennig, W.; Walby, M.; Fallu-Labruyere, A.; Harris, J.; Breus, D.; Grudberg, P.; Warburton, W.K.

    2009-01-01

    A 624-channel Digital Data Acquisition System capable of instrumenting the Segmented Germanium Array at National Superconducting Cyclotron Laboratory has been implemented using Pixie-16 Digital Gamma Finder modules by XIA LLC. The system opens an opportunity for determination of the first interaction position of a γ ray in a SeGA detector from implementation of γ-ray tracking. This will translate into a significantly improved determination of angle of emission, and in consequence much better Doppler corrections for experiments with fast beams. For stopped-beam experiments the system provides means for zero dead time measurements of rare decays, which occur on time scales of microseconds.

  20. Digital Data Acquisition System for experiments with segmented detectors at National Superconducting Cyclotron Laboratory

    Science.gov (United States)

    Starosta, K.; Vaman, C.; Miller, D.; Voss, P.; Bazin, D.; Glasmacher, T.; Crawford, H.; Mantica, P.; Tan, H.; Hennig, W.; Walby, M.; Fallu-Labruyere, A.; Harris, J.; Breus, D.; Grudberg, P.; Warburton, W. K.

    2009-11-01

    A 624-channel Digital Data Acquisition System capable of instrumenting the Segmented Germanium Array at National Superconducting Cyclotron Laboratory has been implemented using Pixie-16 Digital Gamma Finder modules by XIA LLC. The system opens an opportunity for determination of the first interaction position of a γ ray in a SeGA detector from implementation of γ-ray tracking. This will translate into a significantly improved determination of angle of emission, and in consequence much better Doppler corrections for experiments with fast beams. For stopped-beam experiments the system provides means for zero dead time measurements of rare decays, which occur on time scales of microseconds.

  1. Measurements of timing resolution of ultra-fast silicon detectors with the SAMPIC waveform digitizer

    Energy Technology Data Exchange (ETDEWEB)

    Breton, D. [CNRS/IN2P3/LAL Orsay, Université Paris-Saclay, F-91898 Orsay (France); De Cacqueray, V.; Delagnes, E. [IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette (France); Grabas, H. [Santa Cruz Institute for Particle Physics UC Santa Cruz, CA 95064 (United States); Maalmi, J. [CNRS/IN2P3/LAL Orsay, Université Paris-Saclay, F-91898 Orsay (France); Minafra, N. [Dipartimento Interateneo di Fisica di Bari, Bari (Italy); CERN, Geneva (Switzerland); Royon, C. [University of Kansas, Lawrence (United States); Saimpert, M., E-mail: matthias.saimpert@cern.ch [IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette (France)

    2016-11-01

    The SAMpler for PICosecond time (SAMPIC) chip has been designed by a collaboration including CEA/IRFU/SEDI, Saclay and CNRS/LAL/SERDI, Orsay. It benefits from both the quick response of a time to digital converter and the versatility of a waveform digitizer to perform accurate timing measurements. Thanks to the sampled signals, smart algorithms making best use of the pulse shape can be used to improve time resolution. A software framework has been developed to analyse the SAMPIC output data and extract timing information by using either a constant fraction discriminator or a fast cross-correlation algorithm. SAMPIC timing capabilities together with the software framework have been tested using pulses generated by a signal generator or by a silicon detector illuminated by a pulsed infrared laser. Under these ideal experimental conditions, the SAMPIC chip has proven to be capable of timing resolutions down to 4 ps with synthesized signals and 40 ps with silicon detector signals.

  2. 360/degree/ 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 a wide range of phase shift. A description is given of a phase detector that is being built at Los Alamos National Laboratory for the Fusion Materials Irradiation Test (FMIT) project. The specifications are 100-kHz bandwidth, linearity of /plus or minus/1/degree/ over /plus or minus/180/degree/ of phase shift, and 0.66/degree/ resolution. To date, the circuit has achieved the bandwidth and resolution. The linearity is approximately /plus or minus/3/degree/ over /plus or minus/180/degree/ phase shift. 3 refs

  3. Testing digital recursive filtering method for radiation measurement channel using pin diode detector

    International Nuclear Information System (INIS)

    Talpalariu, C. M.; Talpalariu, J.; Popescu, O.; Mocanasu, M.; Lita, I.; Visan, D. A.

    2016-01-01

    In this work we have studied a software filtering method implemented in a pulse counting computerized measuring channel using PIN diode radiation detector. In case our interest was focalized for low rate decay radiation measurement accuracies improvement and response time optimization. During works for digital mathematical algorithm development, we used a hardware radiation measurement channel configuration based on PIN diode BPW34 detector, preamplifier, filter and programmable counter, computer connected. We report measurement results using two digital recursive methods in statically and dynamically field evolution. Software for graphical input/output real time diagram representation was designed and implemented, facilitating performances evaluation between the response of fixed configuration software recursive filter and dynamically adaptive configuration recursive filter. (authors)

  4. Direct conversion Si and CdZnTe detectors for digital mammography

    CERN Document Server

    Yin Shi Shi; Maeding, D; Mainprize, J; Mawdsley, G; Yaffe, M J; Gordon, E E; Hamilton, W J

    2000-01-01

    Hybrid pixel detector arrays that convert X-rays directly into charge signals are under development at NOVA for application to digital mammography. This technology also has wide application possibilities in other fields of radiology or in industrial imaging, nondestructive evaluation (NDE) and nondestructive inspection (NDI). These detectors have potentially superior properties compared to either emulsion-based film-screen systems which has nonlinear response to X-rays, or phosphor-based detectors in which there is an intermediate step of X-ray to light photon conversion (Feig and Yaffe, Radiol. Clinics North America 33 (1995) 1205-1230). Potential advantages of direct conversion detectors are high quantum efficiencies (QE) of 98% or higher (for 0.3 mm thick CdZnTe detector with 20 keV X-rays), improved contrast, high sensitivity and low intrinsic noise. These factors are expected to contribute to high detective quantum efficiency (DQE). The prototype hybrid pixel detector developed has 50x50 mu m pixel size,...

  5. Analytical approximations to the Hotelling trace for digital x-ray detectors

    Science.gov (United States)

    Clarkson, Eric; Pineda, Angel R.; Barrett, Harrison H.

    2001-06-01

    The Hotelling trace is the signal-to-noise ratio for the ideal linear observer in a detection task. We provide an analytical approximation for this figure of merit when the signal is known exactly and the background is generated by a stationary random process, and the imaging system is an ideal digital x-ray detector. This approximation is based on assuming that the detector is infinite in extent. We test this approximation for finite-size detectors by comparing it to exact calculations using matrix inversion of the data covariance matrix. After verifying the validity of the approximation under a variety of circumstances, we use it to generate plots of the Hotelling trace as a function of pairs of parameters of the system, the signal and the background.

  6. 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.

  7. 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.

  8. Digital pulse-timing technique for the neutron detector array NEDA

    Energy Technology Data Exchange (ETDEWEB)

    Modamio, V., E-mail: victor.modamio@lnl.infn.it [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Valiente-Dobón, J.J. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Jaworski, G. [Faculty of Physics, Warsaw University of Technology, 00-662 Warszawa (Poland); Heavy Ion Laboratory, University of Warsaw, 02-093 Warszawa (Poland); Hüyük, T. [Instituto de Física Corpuscular, CSIC-Universitat de València, E-46980 Valencia (Spain); Triossi, A. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Egea, J. [Instituto de Física Corpuscular, CSIC-Universitat de València, E-46980 Valencia (Spain); Department of Electronic Engineering, Universitat de València, E-46100 Burjassot (Spain); Di Nitto, A. [Johannes Gutenberg-Universität Mainz, D-55099 Mainz (Germany); Söderström, P.-A. [RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, 351-0198 Saitama (Japan); Agramunt Ros, J. [Instituto de Física Corpuscular, CSIC-Universitat de València, E-46980 Valencia (Spain); Angelis, G. de [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); France, G. de [GANIL, CEA/DSAM and CNRS/IN2P3, F-14076 Caen (France); Erduran, M.N. [Faculty of Engineering and Natural Sciences, Istanbul Sabahattin Zaim University, 34303 Istanbul (Turkey); and others

    2015-03-01

    A new digital pulse-timing algorithm, to be used with the future neutron detector array NEDA, has been developed and tested. The time resolution of four 5 in. diameter photomultiplier tubes (XP4512, R4144, R11833-100, and ET9390-kb), coupled to a cylindrical 5 in. by 5 in. BC501A liquid scintillator detector was measured by employing digital sampling electronics and a constant fraction discriminator (CFD) algorithm. The zero crossing of the CFD algorithm was obtained with a cubic spline interpolation, which was continuous up to the second derivative. The performance of the algorithm was studied at sampling rates of 500 MS/s and 200 MS/s. The time resolution obtained with the digital electronics was compared to the values acquired with a standard analog CFD. The result of this comparison shows that the time resolution from the analog and the digital measurements at 500 MS/s and at 200 MS/s are within 15% for all the tested photomultiplier tubes.

  9. Imaging performance of an amorphous selenium digital mammography detector in a breast tomosynthesis system

    International Nuclear Information System (INIS)

    Zhao Bo; Zhao Wei

    2008-01-01

    In breast tomosynthesis a rapid sequence of N images is acquired when the x-ray tube sweeps through different angular views with respect to the breast. Since the total dose to the breast is kept the same as that in regular mammography, the exposure used for each image of tomosynthesis is 1/N. The low dose and high frame rate pose a tremendous challenge to the imaging performance of digital mammography detectors. The purpose of the present work is to investigate the detector performance in different operational modes designed for tomosynthesis acquisition, e.g., binning or full resolution readout, the range of view angles, and the number of views N. A prototype breast tomosynthesis system with a nominal angular range of ±25 deg. was used in our investigation. The system was equipped with an amorphous selenium (a-Se) full field digital mammography detector with pixel size of 85 μm. The detector can be read out in full resolution or 2x1 binning (binning in the tube travel direction). The focal spot blur due to continuous tube travel was measured for different acquisition geometries, and it was found that pixel binning, instead of focal spot blur, dominates the detector modulation transfer function (MTF). The noise power spectrum (NPS) and detective quantum efficiency (DQE) of the detector were measured with the exposure range of 0.4-6 mR, which is relevant to the low dose used in tomosynthesis. It was found that DQE at 0.4 mR is only 20% less than that at highest exposure for both detector readout modes. The detector temporal performance was categorized as lag and ghosting, both of which were measured as a function of x-ray exposure. The first frame lags were 8% and 4%, respectively, for binning and full resolution mode. Ghosting is negligible and independent of the frame rate. The results showed that the detector performance is x-ray quantum noise limited at the low exposures used in each view of tomosynthesis, and the temporal performance at high frame rate (up to

  10. Non-destructive assay employing 2D and 3D digital radiographic imaging acquired with thermal neutrons and reactor-produced radioisotopes

    International Nuclear Information System (INIS)

    Silvani, Maria Ines; Almeida, Gevaldo Lisboa de; Lopes, Ricardo T.

    2011-01-01

    The inner structure of some objects can only be visualized by using suitable techniques, when safety reasons or expensive costs preclude the application of invasive procedures. The kind of agent rendering an object partially transparent, unveiling thus its features, depends upon the object size and composition. As a rough rule of thumb, light materials are transparent to gamma and X-rays while the heavy ones are transparent to neutrons. When, after traversing an object, they hit a proper 2-D detector, a radiograph is produced representing a convoluted cross section, called projection, of that object. Taking a large number of such projections for different object attitudes, it is possible to obtain a 3-D tomography of the object as a map of attenuation coefficients. This procedure however, besides a time-consuming task, requires specially tailored equipment and software, not always available or affordable. Yet, in some circumstances it is feasible to replace the 3-D tomography by a stereoscopy, allowing one to visualize the spatial configuration of the object under analysis. In this work, 2-D and 3-D radiographic images have been acquired using thermal neutrons and reactor-produced radioisotopes and proper imaging plates as detectors. The stereographic vision has been achieved by taking two radiographs of the same object at different angles, from the detector point of view. After a treatment to render them red-white and green-white they were properly merged to yield a single image capable to be watched with red-green glasses. All the image treatment and rendering has been performed with the software ImageJ. (author)

  11. 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)

  12. Digital pulse processing techniques for high resolution amplitude measurement of radiation detector

    International Nuclear Information System (INIS)

    Singhai, P.; Roy, A.; Dhara, P.; Chatterjee, S.

    2012-01-01

    The digital pulse processing techniques for high resolution amplitude measurement of radiation detector pulse is an effective replacement of expensive and bulky analog processing as the digital domain offers higher channel density and at the same time it is cheaper. We have demonstrated a prototype digital setup with highspeed sampling ADC with sampling frequency of 80-125 MHz followed by series of IIR filters for pulse shaping in a trigger-less acquisition mode. The IIR filters, peak detection algorithm and the data write-out logic was written on VHDL and implemented on FPGA. We used CAMAC as the read out platform. In conjunction with the full hardware implementation we also used a mixed platform with VME digitizer card with raw-sample read out using C code. The rationale behind this mixed platform is to test out various filter algorithms quickly on C and also to benchmark the performance of the chip level ADCs against the standard commercial digitizer in terms of noise or resolution. The paper describes implementation of both the methods with performance obtained in both the methods. (author)

  13. CDF central detector installation. An efficient merge of digital photogrammetry and laser tracker metrology

    International Nuclear Information System (INIS)

    Greenwood, John A.; Wojcik, George J.

    2003-01-01

    Metrology for Run II at the Collider Detector at Fermilab (CDF) required a very complex geodetic survey. The Collision Hall network, surveyed with a Laser Tracker and digital level, provides a constraining network for the positioning of the Central Detector (CD). A part-based Laser Tracker network, which surrounded the 2,000-ton CD, was used as control for assembly. Subassembly surveys of the Detector's major components were measured as independent networks using Laser Tracker, V-STARS/S (Video-Simultaneous Triangulation And Resection System/Single camera) digital photogrammetry system, and BETS (Brunson Electronic Theodolite System) theodolite triangulation system. Each subassembly survey was transformed into and constrained by the part-based network. For roll-in, the CD part-based network was transformed into the Collision Hall network coordinate system. The CD was positioned in the Collision Hall using two Laser Trackers in 'stakeout mode.' This paper discusses the survey, adjustment, transformation, and precision of the various networks. (author)

  14. Accuracy and precision of patient positioning for pelvic MR-only radiation therapy using digitally reconstructed radiographs

    Science.gov (United States)

    Kemppainen, R.; Vaara, T.; Joensuu, T.; Kiljunen, T.

    2018-03-01

    Background and Purpose. Magnetic resonance imaging (MRI) has in recent years emerged as an imaging modality to drive precise contouring of targets and organs at risk in external beam radiation therapy. Moreover, recent advances in MRI enable treatment of cancer without computed tomography (CT) simulation. A commercially available MR-only solution, MRCAT, offers a single-modality approach that provides density information for dose calculation and generation of positioning reference images. We evaluated the accuracy of patient positioning based on MRCAT digitally reconstructed radiographs (DRRs) by comparing to standard CT based workflow. Materials and Methods. Twenty consecutive prostate cancer patients being treated with external beam radiation therapy were included in the study. DRRs were generated for each patient based on the planning CT and MRCAT. The accuracy assessment was performed by manually registering the DRR images to planar kV setup images using bony landmarks. A Bayesian linear mixed effects model was used to separate systematic and random components (inter- and intra-observer variation) in the assessment. In addition, method agreement was assessed using a Bland-Altman analysis. Results. The systematic difference between MRCAT and CT based patient positioning, averaged over the study population, were found to be (mean [95% CI])  -0.49 [-0.85 to  -0.13] mm, 0.11 [-0.33 to  +0.57] mm and  -0.05 [-0.23 to  +0.36] mm in vertical, longitudinal and lateral directions, respectively. The increases in total random uncertainty were estimated to be below 0.5 mm for all directions, when using MR-only workflow instead of CT. Conclusions. The MRCAT pseudo-CT method provides clinically acceptable accuracy and precision for patient positioning for pelvic radiation therapy based on planar DRR images. Furthermore, due to the reduction of geometric uncertainty, compared to dual-modality workflow, the approach is likely to improve the total

  15. 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

  16. Modeling Radiation Damage Effects in 3D Pixel Digitization for the ATLAS Detector

    CERN Document Server

    Giugliarelli, Gilberto; The ATLAS collaboration

    2018-01-01

    Silicon Pixel detectors are at the core of the current and planned upgrade of the ATLAS experiment. They constitute the part of ATLAS closest to the interaction point and for this reason they will be exposed – over their lifetime – to a significant amount of radiation: prior to the HL-LHC, the innermost layers will receive a fluence of 10^15 neq/cm2 and their HL–LHC upgrades will have to 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.

  17. Numerical analysis of edge effects in side illuminated strip detectors for digital radiology

    CERN Document Server

    Krizaj, D

    2000-01-01

    The influence of edge defects on side illuminated X-ray strip detectors for digital radiology is investigated by numerical device modeling. By assuming positive fixed oxide charges on side and top surfaces simulations have shown strong curvature of the equipotential lines in the edge region. A fraction of the edge generated current surpasses the edge guard-ring junction and is collected by the readout strips. As a consequence, strips cannot be placed close to the edge of the structure and collection efficiency is reduced. An n-on-n instead of a p-on-n strip detector is proposed enabling collection of edge generated carriers by a very narrow guard-ring junction and placement of the readout strip close to the edge without increase of the strip leakage current.

  18. Calcified carotid atherosclerotic plaques on digital panoramic radiographs in patients with Type II diabetes mellitus: A case control study

    Directory of Open Access Journals (Sweden)

    Neha Khambete

    2015-01-01

    Full Text Available Aim: Diabetes mellitus is associated with accelerated carotid artery atherosclerosis and increased risk of stroke. This study was conducted with the objective of determining the prevalence of calcified atherosclerotic plaques on panoramic radiographs of patients with Type II diabetes mellitus. Materials and Methods: Panoramic radiographs of 100 patients (age range 50-84 years with known history of type II diabetes mellitus, visiting the outpatient department were evaluated for the presence of calcified atherosclerotic plaques. Age- and sex-matched controls were evaluated in the same manner. Statistical comparison of prevalence rates was done. Results: The radiographs of diabetics (mean age: 64.45 years revealed that 26% had atheromatous plaques, whereas those of controls (mean age: 65.36 years revealed that 6% had atheromatous plaques. A statistically significant difference (P = 0.01410 was obtained using Yates′ Chi-square test. Conclusion: People with diabetes mellitus had a greater prevalence of calcified atherosclerotic plaques on panoramic radiographs than non-diabetics. Panoramic radiographs of diabetic patients should be screened for the presence of carotid artery atheromatous plaques for timely medical referral of asymptomatic patients and avoiding any further serious consequences like cerebrovascular accidents.

  19. A digital data acquisition scheme for SPECT and PET small animal imaging detectors for Theranostic applications

    Science.gov (United States)

    Georgiou, M.; Fysikopoulos, E.; Loudos, G.

    2017-11-01

    Nanoparticle based drug delivery is considered as a new, promising technology for the efficient treatment of various diseases. When nanoparticles are radiolabelled it is possible to image them, using molecular imaging techniques. The use of magnetic nanoparticles in hyperthermia is one of the most promising nanomedicine directions and requires the accurate, non-invasive, monitoring of temperature increase and drug release. The combination of imaging and therapy has opened the very promising Theranostics domain. In this work, we present a digital data acquisition scheme for nuclear medicine dedicated detectors for Theranostic applications.

  20. Digital and Analog Electronics for an autonomous, deep-sea, Gamma Ray Burst Neutrino prototype detector

    Directory of Open Access Journals (Sweden)

    Manolopoulos K.

    2016-01-01

    Full Text Available GRBNeT is a Gamma Ray Burst Neutrino Telescope made of autonomously operated arrays of deep-sea light detectors, anchored to the sea-bed without any cabled connection to the shore. This paper presents the digital and analog electronics that we have designed and developed for the GRBNeT prototype. We describe the requirements for these electronics and present their design and functionality. We present low-power analog electronics for the PMTs utilized in the GRBNeT prototype and the FPGA based digital system for data selection and storage. We conclude with preliminary performance measurements of the electronics systems for the GRBNeT prototype.

  1. 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.

  2. 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

  3. Study on Digital Pulse Shape Discrimination System in BF{sub 3} Detector

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jinhyeong; Kim, J. H.; Choi, H. D. [Seoul National Univ., Seoul (Korea, Republic of)

    2013-10-15

    In this study, we develop the digital PSD system and discriminate the background signal of BF{sub 3}. Spectrum shapes are different according to the t{sub start} setting method, and it is favorable to set it as the certain ratio of maximum height. In future, it will be performed to vary t{sub start} point to optimize the pulse discrimination. To quantify the performance, Figure Of Merit (FOM) will be determined. For the nuclear non-proliferation and safeguards, an accurate and reliable measurement of nuclear material is essential. The nuclear material emits neutron and γ-ray, simultaneously. For the accurate detection of the nuclear material, neutron should be discriminated from γ-ray or background radiation. In previous study, N. S. Jung developed pulse shape analysis method based on NIM and CAMAC system. However, applications of other discrimination methods based on different detection modules or changing parameters are time-and-money consuming procedures in analogue systems. Today, the performance of digitizers is improved and it replaces some radiation measurement systems which require simple and portable equipment. Digital Pulse Shape Discrimination (PSD) method by using a digital oscilloscope is developed and applied to a neutron detection system by using BF{sub 3} detector in this study.

  4. A High Density Low Cost Digital Signal Processing Module for Large Scale Radiation Detectors

    International Nuclear Information System (INIS)

    Tan, Hui; Hennig, Wolfgang; Walby, Mark D.; Breus, Dimitry; Harris, Jackson T.; Grudberg, Peter M.; Warburton, William K.

    2013-06-01

    A 32-channel digital spectrometer PIXIE-32 is being developed for nuclear physics or other radiation detection applications requiring digital signal processing with large number of channels at relatively low cost. A single PIXIE-32 provides spectrometry and waveform acquisition for 32 input signals per module whereas multiple modules can be combined into larger systems. It is based on the PCI Express standard which allows data transfer rates to the host computer of up to 800 MB/s. Each of the 32 channels in a PIXIE-32 module accepts signals directly from a detector preamplifier or photomultiplier. Digitally controlled offsets can be individually adjusted for each channel. Signals are digitized in 12-bit, 50 MHz multi-channel ADCs. Triggering, pile-up inspection and filtering of the data stream are performed in real time, and pulse heights and other event data are calculated on an event-by event basis. The hardware architecture, internal and external triggering features, and the spectrometry and waveform acquisition capability of the PIXIE- 32 as well as its capability to distribute clock and triggers among multiple modules, are presented. (authors)

  5. Pulse discrimination of background and gamma-ray source by digital pulse shape discrimination in a BF3 detector

    International Nuclear Information System (INIS)

    Kim, Jinhyung; Kim, J. H.; Choi, H. D.

    2014-01-01

    As a representative method of non-destructive assay, accurate neutron measurement is difficult due to large background radiation such as γ-ray, secondary radiation, spurious pulse, etc. In a BF 3 detector, the process of signal generation is different between neutron and other radiations. As the development of detection technique, all of signal data can be digitized by digital measurement method. In the previous study, Applied Nuclear Physics Group in Seoul National University has developed digital Pulse Shape Discrimination (PSD) method using digital oscilloscope. In this study, optimization of parameters for pulse discrimination is discussed and γ-ray region is determined by measuring 60 Co source. The background signal of BF 3 detector is discriminated by digital PSD system. Parameters for PSD are optimized through FOM calculation. And the γ-ray region is determined by measuring 60 Co source. In the future, the performance of developed system will be tested in low and high intensity neutron field

  6. 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)

  7. Diagnostic yield of ink-jet prints from digital radiographs for the assessment of approximal carious lesions: ROC-analysis

    International Nuclear Information System (INIS)

    Schulze, Ralf K.W.; Grimm, Stefanie; Schulze, Dirk; Voss, Kai; Keller, Hans-Peter; Wedel, Matthias

    2011-01-01

    Aims: To investigate the diagnostic quality of different quality, individually calibrated ink-jet printers for the very challenging dental radiographic task of approximal carious lesion detection. Materials and methods: A test-pattern evaluating resolution, contrast and homogeneity of the ink-jet prints was developed. 50 standardized dental radiographs each showing two neighbouring teeth in natural contact were printed on glossy paper with calibrated, randomly selected ink-jet printers (Canon S520 and iP4500, Epson Stylus Photo R2400). Printing size equalled the viewing size on a 17'' cathode-ray-tube monitor daily quality-tested according to German regulations. The true caries status was determined from serial sectioning and microscopic evaluation. 16 experienced observers evaluated the radiographs on a five-point confidence scale on all prints plus the viewing monitor with respect to the visibility of a carious lesion. A non-parametric Receiver-Operating Characteristics (ROC-) analysis was performed explicitly designed for the evaluation of readings stemming from identical samples but different modality. Significant differences are expressed by a critical ratio z exceeding ±2. Diagnostic accuracy was determined by the area (Az) underneath the ROC-curves. Results: Average Az-values ranged between 0.62 (S520 and R2400) and 0.64 (monitor, iP4500), with no significant difference between modalities (P = 0.172). Neither significant (range mean z: -0.40 (S520) and -0.11 (iP4500)) nor clinically relevant differences were found between printers and viewing monitor. Conclusions: Our results for a challenging task in dental radiography indicate that calibrated, off-the-shelf ink-jet printers are able to reproduce (dental) radiographs at quality levels sufficient for radiographic diagnosis in a typical dental working environment.

  8. Diagnostic yield of ink-jet prints from digital radiographs for the assessment of approximal carious lesions: ROC-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, Ralf K.W., E-mail: rschulze@mail.uni-mainz.de [Poliklinik fuer Zahnaerztliche Chirurgie, University Medical Center of the Johannes Gutenberg-University, Augustusplatz 2, D-55131 Mainz (Germany); Grimm, Stefanie, E-mail: StefanieGrimm@gmx.de [Poliklinik fuer Zahnaerztliche Chirurgie, University Medical Center of the Johannes Gutenberg-University, Augustusplatz 2, D-55131 Mainz (Germany); Schulze, Dirk, E-mail: dirk.schulze@uniklinik-freiburg.de [Klinik fuer Mund,- Kiefer- und Gesichtschirurgie, Sektion Roentgen, Universitaetsklinikum Freiburg, Hugstetterstr. 55, D-79106 Freiburg (Germany); Voss, Kai, E-mail: zahnarzt@drvoss.eu [Zahnaerztekammer Schleswig-Holstein, Vorstand fuer Praxisfuehrung, Westring 496, D- 24106 Kiel (Germany); Keller, Hans-Peter, E-mail: hans-peter.keller@din.de [NA Dental (NADENT) im DIN, Alexander-Wellendorff-Str. 2, D-75172 Pforzheim (Germany); Wedel, Matthias, E-mail: matthias.wedel@siemens.com [Siemens AG, Medical Solutions, Postfach 32 60, D-91050 Erlangen (Germany)

    2011-08-15

    Aims: To investigate the diagnostic quality of different quality, individually calibrated ink-jet printers for the very challenging dental radiographic task of approximal carious lesion detection. Materials and methods: A test-pattern evaluating resolution, contrast and homogeneity of the ink-jet prints was developed. 50 standardized dental radiographs each showing two neighbouring teeth in natural contact were printed on glossy paper with calibrated, randomly selected ink-jet printers (Canon S520 and iP4500, Epson Stylus Photo R2400). Printing size equalled the viewing size on a 17'' cathode-ray-tube monitor daily quality-tested according to German regulations. The true caries status was determined from serial sectioning and microscopic evaluation. 16 experienced observers evaluated the radiographs on a five-point confidence scale on all prints plus the viewing monitor with respect to the visibility of a carious lesion. A non-parametric Receiver-Operating Characteristics (ROC-) analysis was performed explicitly designed for the evaluation of readings stemming from identical samples but different modality. Significant differences are expressed by a critical ratio z exceeding {+-}2. Diagnostic accuracy was determined by the area (Az) underneath the ROC-curves. Results: Average Az-values ranged between 0.62 (S520 and R2400) and 0.64 (monitor, iP4500), with no significant difference between modalities (P = 0.172). Neither significant (range mean z: -0.40 (S520) and -0.11 (iP4500)) nor clinically relevant differences were found between printers and viewing monitor. Conclusions: Our results for a challenging task in dental radiography indicate that calibrated, off-the-shelf ink-jet printers are able to reproduce (dental) radiographs at quality levels sufficient for radiographic diagnosis in a typical dental working environment.

  9. 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

  10. Digital algorithms for parallel pipelined single-detector homodyne fringe counting in laser interferometry

    Science.gov (United States)

    Rerucha, Simon; Sarbort, Martin; Hola, Miroslava; Cizek, Martin; Hucl, Vaclav; Cip, Ondrej; Lazar, Josef

    2016-12-01

    The homodyne detection with only a single detector represents a promising approach in the interferometric application which enables a significant reduction of the optical system complexity while preserving the fundamental resolution and dynamic range of the single frequency laser interferometers. We present the design, implementation and analysis of algorithmic methods for computational processing of the single-detector interference signal based on parallel pipelined processing suitable for real time implementation on a programmable hardware platform (e.g. the FPGA - Field Programmable Gate Arrays or the SoC - System on Chip). The algorithmic methods incorporate (a) the single detector signal (sine) scaling, filtering, demodulations and mixing necessary for the second (cosine) quadrature signal reconstruction followed by a conic section projection in Cartesian plane as well as (a) the phase unwrapping together with the goniometric and linear transformations needed for the scale linearization and periodic error correction. The digital computing scheme was designed for bandwidths up to tens of megahertz which would allow to measure the displacements at the velocities around half metre per second. The algorithmic methods were tested in real-time operation with a PC-based reference implementation that employed the advantage pipelined processing by balancing the computational load among multiple processor cores. The results indicate that the algorithmic methods are suitable for a wide range of applications [3] and that they are bringing the fringe counting interferometry closer to the industrial applications due to their optical setup simplicity and robustness, computational stability, scalability and also a cost-effectiveness.

  11. 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.

  12. The ALTRO Chip A 16-channel A/D Converter and Digital Processor for Gas Detectors

    CERN Document Server

    Esteve-Bosch, R; Mota, B; Musa, L

    2003-01-01

    The ALTRO (ALICE TPC Read Out) chip is a mixed-signal integrated circuit designed to be one of the building blocks of the readout electronics for gas detectors. Originally conceived and optimised for the Time Projection Chamber (TPC) of the ALICE experiment at the CERN LHC, its architecture and programmability makes it suitable for the readout of a wider class of gas detectors. In one single chip, the analogue signals from 16 channels are digitised, processed, compressed and stored in a multi-acquisition memory. The Analogue-to- Digital converters embedded in the chip have a 10-bit dynamic range and a maximum sampling rate in the range of 20 to 40MHz. After digitisation, a pipelined hardwired Processor is able to remove from the input signal a wide range of systematic and non-systematic perturbations, related to the non-ideal behaviour of the detector, temperature variation of the electronics, environmental noise, etc. Moreover, the Processor is able to suppress the signal tail within 1mus after the pulse pea...

  13. Fast digitization and discrimination of prompt neutron and photon signals using a novel silicon carbide detector

    International Nuclear Information System (INIS)

    Brandon W. Blackburn; James T. Johnson; Scott M. Watson; David L. Chichester; James L. Jones; Frank H. Ruddy; John G. Seidel; Robert W. Flammang

    2007-01-01

    Current requirements of some Homeland Security active interrogation projects for the detection of Special Nuclear Material (SNM) necessitate the development of faster inspection and acquisition capabilities. In order to do so, fast detectors which can operate during and shortly after intense interrogation radiation flashes are being developed. Novel silicon carbide (SiC) semiconductor Schottky diodes have been utilized as robust neutron and photon detectors in both pulsed photon and pulsed neutron fields and are being integrated into active inspection environments to allow exploitation of both prompt and delayed emissions. These detectors have demonstrated the capability of detecting both photon and neutron events during intense photon flashes typical of an active inspection environment. Beyond the inherent insensitivity of SiC to gamma radiation, fast digitization and processing has demonstrated that pulse shape discrimination (PSD) in combination with amplitude discrimination can further suppress unwanted gamma signals and extract fast neutron signatures. Usable neutron signals have been extracted from mixed radiation fields where the background has exceeded the signals of interest by >1000:1

  14. Low level radioactivity measurements with phoswich detectors using coincident techniques and digital pulse processing analysis.

    Science.gov (United States)

    de la Fuente, R; de Celis, B; del Canto, V; Lumbreras, J M; de Celis Alonso, B; Martín-Martín, A; Gutierrez-Villanueva, J L

    2008-10-01

    A new system has been developed for the detection of low radioactivity levels of fission products and actinides using coincidence techniques. The device combines a phoswich detector for alpha/beta/gamma-ray recognition with a fast digital card for electronic pulse analysis. The phoswich can be used in a coincident mode by identifying the composed signal produced by the simultaneous detection of alpha/beta particles and X-rays/gamma particles. The technique of coincidences with phoswich detectors was proposed recently to verify the Nuclear Test Ban Treaty (NTBT) which established the necessity of monitoring low levels of gaseous fission products produced by underground nuclear explosions. With the device proposed here it is possible to identify the coincidence events and determine the energy and type of coincident particles. The sensitivity of the system has been improved by employing liquid scintillators and a high resolution low energy germanium detector. In this case it is possible to identify simultaneously by alpha/gamma coincidence transuranic nuclides present in environmental samples without necessity of performing radiochemical separation. The minimum detectable activity was estimated to be 0.01 Bq kg(-1) for 0.1 kg of soil and 1000 min counting.

  15. Low level radioactivity measurements with phoswich detectors using coincident techniques and digital pulse processing analysis

    International Nuclear Information System (INIS)

    Fuente, R. de la; Celis, B. de; Canto, V. del; Lumbreras, J.M.; Celis, Alonso B. de; Martin-Martin, A.; Gutierrez-Villanueva, J.L.

    2008-01-01

    A new system has been developed for the detection of low radioactivity levels of fission products and actinides using coincidence techniques. The device combines a phoswich detector for α/β/γ-ray recognition with a fast digital card for electronic pulse analysis. The phoswich can be used in a coincident mode by identifying the composed signal produced by the simultaneous detection of α/β particles and X-rays/γ particles. The technique of coincidences with phoswich detectors was proposed recently to verify the Nuclear Test Ban Treaty (NTBT) which established the necessity of monitoring low levels of gaseous fission products produced by underground nuclear explosions. With the device proposed here it is possible to identify the coincidence events and determine the energy and type of coincident particles. The sensitivity of the system has been improved by employing liquid scintillators and a high resolution low energy germanium detector. In this case it is possible to identify simultaneously by α/γ coincidence transuranic nuclides present in environmental samples without necessity of performing radiochemical separation. The minimum detectable activity was estimated to be 0.01 Bq kg -1 for 0.1 kg of soil and 1000 min counting

  16. Development of an MRI-compatible digital SiPM detector stack for simultaneous PET/MRI.

    Science.gov (United States)

    Düppenbecker, Peter M; Weissler, Bjoern; Gebhardt, Pierre; Schug, David; Wehner, Jakob; Marsden, Paul K; Schulz, Volkmar

    2016-02-01

    Advances in solid-state photon detectors paved the way to combine positron emission tomography (PET) and magnetic resonance imaging (MRI) into highly integrated, truly simultaneous, hybrid imaging systems. Based on the most recent digital SiPM technology, we developed an MRI-compatible PET detector stack, intended as a building block for next generation simultaneous PET/MRI systems. Our detector stack comprises an array of 8 × 8 digital SiPM channels with 4 mm pitch using Philips Digital Photon Counting DPC 3200-22 devices, an FPGA for data acquisition, a supply voltage control system and a cooling infrastructure. This is the first detector design that allows the operation of digital SiPMs simultaneously inside an MRI system. We tested and optimized the MRI-compatibility of our detector stack on a laboratory test bench as well as in combination with a Philips Achieva 3 T MRI system. Our design clearly reduces distortions of the static magnetic field compared to a conventional design. The MRI static magnetic field causes weak and directional drift effects on voltage regulators, but has no direct impact on detector performance. MRI gradient switching initially degraded energy and timing resolution. Both distortions could be ascribed to voltage variations induced on the bias and the FPGA core voltage supply respectively. Based on these findings, we improved our detector design and our final design shows virtually no energy or timing degradations, even during heavy and continuous MRI gradient switching. In particular, we found no evidence that the performance of the DPC 3200-22 digital SiPM itself is degraded by the MRI system.

  17. Physical characteristics of GE Senographe Essential and DS digital mammography detectors

    International Nuclear Information System (INIS)

    Ghetti, Caterina; Borrini, Adriano; Ortenzia, Ornella; Rossi, Raffaella; Ordonez, Pedro L.

    2008-01-01

    The purpose of this study was to investigate physical characteristics of two full field digital mammography (FFDM) systems (GE Senographe Essential and DS). Both are indirect conversion (x ray to light) a-Si flat panels coupled with a CsI(Tl) scintillator. The examined systems have the same pixel size (100 μm) but a different field of view: a conventional size 23x19.2 cm 2 and a large field 24x30.7 cm 2 , specifically designed to image large breasts. In the GE Senographe Essential model relevant improvements in flat panel design were implemented and new deposition tools for metal, a-Si, and CsI(Tl) were introduced by GE. These changes in detector design are expected to be beneficial for advanced applications such as breast tomosynthesis. The presampling modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE) were measured for a wide range of exposure (25-240 μGy) with a RQA-M2 technique (28 kVp with a Mo/Mo target/filter combination and 2 mm of additional aluminum filtration). At 1, 2, and at 4 lp/mm MTF is equal to 0.9, 0.76, and 0.46 for the conventional field detector and to 0.85, 0.59, and 0.24 for the large field detector. The latter detector exhibits an improved NNPS due to a lower electronic noise and a better DQE that reaches 60%. In addition a contrast-detail analysis was performed with CDMAM 3.4 phantom and CDCOM software: GE Senographe DS showed statistically significant poorer detection ability in comparison with the GE Senographe Essential. These results could have been expected, at least qualitatively, considering the relative DQE of the two systems

  18. A CdZnTe slot-scanned detector for digital mammography

    International Nuclear Information System (INIS)

    Mainprize, James G.; Ford, Nancy L.; Yin Shi; Gordon, Eli E.; Hamilton, William J.; Tuemer, Tuemay O.; Yaffe, Martin J.

    2002-01-01

    A new high-resolution detector has been developed for use in a slot-scanned digital mammography system. The detector is a hybrid device that consists of a CCD operating in time-delay integration mode that is bonded to a 150-μm-thick CdZnTe photoconductor array. The CCD was designed with a detector element pitch of 50 μm. Two devices were evaluated with differing crystalline quality. Incomplete charge collection was a source of reduction in DQE. This occurs in both devices due to characteristically low mobility-lifetime products for CdZnTe, with the greatest losses demonstrated by the multicrystalline sample. The mobility-lifetime products for the multicrystalline device were found to be 2.4x10 -4 and 4.0x10 -7 cm 2 /V for electrons and holes, respectively. The device constructed with higher quality single crystal CdZnTe demonstrated mobility-lifetime products of 1.0x10 -4 and 4.4x10 -6 cm 2 /V for electrons and holes. The MTF and DQE for the device were measured at several exposures and results were compared to predictions from a linear systems model of signal and noise propagation. The MTF at a spatial frequency of 10 mm -1 exceeded 0.18 and 0.56 along the scan and slot directions, respectively. Scanning motion and CCD design limited the resolution along the scan direction. For an x-ray beam from a tungsten target tube with 40 μm molybdenum filtration operated at 26 kV, the single crystal device demonstrated a DQE(0) of 0.70±0.02 at 7.1x10 -6 C/kg (27 mR) exposure to the detector, despite its relatively poor charge collection efficiency

  19. Interexaminer agreement in caries radiographic diagnosis by conventional and digital radiographs Avaliação interexaminadores no diagnóstico de cáries por meio de radiografias convencionais e digitais

    Directory of Open Access Journals (Sweden)

    Anna Sílvia Penteado Setti da Rocha

    2005-12-01

    Full Text Available The purpose of this research was to compare two digital storage phosphor systems and conventional film, as well as verify the interexaminer agreement in radiographic diagnosis on occlusal and proximal cavities. Two digital systems and conventional radiographic film were used to evaluate 144 tooth surfaces with and without cavities; the radiographs were analyzed and scored in a scale of 4 points. Thirteen undergraduates and an oral radiologist participated as examiners. A light microscopy analysis was accomplished in order to validate the research. The results showed that there was no significant difference between the radiographic systems, however all of them had significant differences when compared to light microscopy, except for the Digora system on the proximal surface when the radiologist was the examiner. In the interexaminer evaluation, a moderate agreement level was obtained, and a fair to moderate level was obtained between the students and the oral radiologist. Regarding the validation (sensitivity, specificity, positive predict and negative predict the values were similar between students and the oral radiologist, except for the sensitivity value on the occlusal surface. The students had the highest number of false-positive results and the oral radiologist the highest number of false-negative results.O objetivo desta pesquisa foi comparar dois sistemas digitais de armazenamento de fósforo e filme convencional, assim como verificar a concordância interexaminadores em diagnóstico radiográfico de cáries oclusais e proximais. Dois sistemas radiográficos digitais e filme convencional foram usados para avaliar 144 superfícies dentais com e sem cavitação; as radiografias foram analisadas e classificadas em uma escala de 4 pontos. Participaram como examinadores 13 alunos de graduação e um radiologista odontológico. Para validar esta pesquisa foram realizadas análises em microscopia ótica. Os resultados mostraram não haver

  20. Detector evaluation of a prototype amorphous selenium-based full field digital mammography system

    Science.gov (United States)

    Jesneck, Jonathan L.; Saunders, Robert S.; Samei, Ehsan; Xia, Jessie Q.; Lo, Joseph Y.

    2005-04-01

    This study evaluated the physical performance of a selenium-based direct full-field digital mammography prototype detector (Siemens Mammomat NovationDR), including the pixel value vs. exposure linearity, the modulation transfer function (MTF), the normalized noise power spectrum (NNPS), and the detective quantum efficiency (DQE). The current detector is the same model which received an approvable letter from FDA for release to the US market. The results of the current prototype are compared to those of an earlier prototype. Two IEC standard beam qualities (RQA-M2: Mo/Mo, 28 kVp, 2 mm Al; RQA-M4: Mo/Mo, 35 kVp, 2 mm Al) and two additional beam qualities (MW2: W/Rh, 28 kVp, 2 mm Al; MW4: W/Rh, 35 kVp, 2 mm Al) were investigated. To calculate the modulation transfer function (MTF), a 0.1 mm Pt-Ir edge was imaged at each beam quality. Detector pixel values responded linearly against exposure values (R2 0.999). As before, above 6 cycles/mm Mo/Mo MTF was slightly higher along the chest-nipple axis compared to the left-right axis. MTF was comparable to the previously reported prototype, with slightly reduced resolution. The DQE peaks ranged from 0.71 for 3.31 μC/kg (12.83 mR) to 0.4 for 0.48 μC/kg (1.86 mR) at 1.75 cycles/mm for Mo/Mo at 28 kVp. The DQE range for W/Rh at 28 kVP was 0.81 at 2.03 μC/kg (7.87 mR) to 0.50 at 0.50 μC/kg (1.94 mR) at 1 cycle/mm. NNPS tended to increase with greater exposures, while all exposures had a significant low-frequency component. Bloom and detector edge artifacts observed previously were no longer present in this prototype. The new detector shows marked noise improvement, with slightly reduced resolution. There remain artifacts due to imperfect gain calibration, but at a reduced magnitude compared to a prototype detector.

  1. Detection of small pulmonary nodules on chest radiographs: efficacy of dual-energy subtraction technique using flat-panel detector chest radiography

    International Nuclear Information System (INIS)

    Oda, S.; Awai, K.; Funama, Y.; Utsunomiya, D.; Yanaga, Y.; Kawanaka, K.; Nakaura, T.; Hirai, T.; Murakami, R.; Nomori, H.; Yamashita, Y.

    2010-01-01

    Aim: To investigate the effect of a double-exposure dual-energy subtraction (DES) technique on the diagnostic performance of radiologists detecting small pulmonary nodules on flat-panel detector (FPD) chest radiographs. Materials and methods: Using FPD radiography 41 sets of chest radiographs were obtained from 26 patients with pulmonary nodules measuring ≤20 mm and from 15 normal participants. Each dataset included standard and corresponding DES images. There were six non-solid, 10 part-solid, and 10 solid nodules. The mean size of the 26 nodules was 15 ± 4.8 mm. Receiver operating characteristic (ROC) analysis was performed to compare the performance of the eight board-certified radiologists. Results: For the eight radiologists, the mean value of the area under the ROC curve (AUC) without and with DES images was 0.62 ± 0.05 and 0.68 ± 0.05, respectively; the difference was statistically significant (p = 0.02). For part-solid nodules, the difference of the mean AUC value was statistically significant (AUC = 0.61 ± 0.07 versus 0.69 ± 0.05; p < 0.01); for non-solid nodules it was not (AUC = 0.62 ± 0.1 versus 0.61 ± 0.09; p = 0.73), and for solid nodules it was not (AUC = 0.75 ± 0.1 versus 0.78 ± 0.08; p = 0.23). For nodules with overlapping bone shadows, the difference of the mean AUC value was statistically significant (p = 0.03), for nodules without overlapping, it was not (p = 0.26). Conclusion: Use of a double-exposure DES technique at FPD chest radiography significantly improved the diagnostic performance of radiologists to detect small pulmonary nodules.

  2. High speed quantitative digital beta autoradiography using a multi-step avalanche detector and an Apple-II microcomputer

    International Nuclear Information System (INIS)

    Bateman, J.E.; Connolly, J.F.; Stephenson, R.

    1985-04-01

    The development of an electronic, digital beta autoradiography system is described. Using a Multi-Step Avalanche/Multi-Wire Proportional Counter (MSA/MWPC) detector system fitted with delay line readout, high speed digital imaging is demonstrated with sub-millimeter spatial resolution. Good proportionality of observed counting rate relative to the known tritium activity is demonstrated. The application of the system to autoradiography in immunoelectrophoresis, histopathology and DNA sequencing is described. (author)

  3. 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

  4. A new ion detector array and digital-signal-processor-based interface

    International Nuclear Information System (INIS)

    Langstaff, D.P.; McGinnity, T.M.; Forbes, D.M.; Birkinshaw, K.; Lawton, M.W.

    1994-01-01

    A new one-dimensional ion detector array on a silicon chip has been developed for use in mass spectrometry. It is much smaller and simpler than electro-optical arrays currently in use and in addition has a higher resolution and a zero noise level. The array consists of a one-dimensional array of metal strips (electrodes) with a pitch of 25 μm on the top surface of a silicon chip, each electrode having its own charge pulse sensor, 8-bit counter and control/interface circuitry. The chip is mounted on a ceramic substrate and is preceded by a micro-channel plate electron multiplier. Chips are butted to give a longer array. Test results show a stable operating region. A digital-signal-processor-based interface is described, which controls the mode of operation and reads the accumulated array data at the maximum rate to avoid counter overflow. (author)

  5. A new ion detector array and digital-signal-processor-based interface

    Energy Technology Data Exchange (ETDEWEB)

    Langstaff, D.P.; McGinnity, T.M.; Forbes, D.M.; Birkinshaw, K. (University Coll. of Wales, Aberystwyth (United Kingdom). Dept. of Physics); Lawton, M.W. (University of Wales Aberystwyth (United Kingdom). Dept. of Computer Science)

    1994-04-01

    A new one-dimensional ion detector array on a silicon chip has been developed for use in mass spectrometry. It is much smaller and simpler than electro-optical arrays currently in use and in addition has a higher resolution and a zero noise level. The array consists of a one-dimensional array of metal strips (electrodes) with a pitch of 25 [mu]m on the top surface of a silicon chip, each electrode having its own charge pulse sensor, 8-bit counter and control/interface circuitry. The chip is mounted on a ceramic substrate and is preceded by a micro-channel plate electron multiplier. Chips are butted to give a longer array. Test results show a stable operating region. A digital-signal-processor-based interface is described, which controls the mode of operation and reads the accumulated array data at the maximum rate to avoid counter overflow. (author).

  6. A time digitizer for the microstrip detectors of the PANDA MVD

    Energy Technology Data Exchange (ETDEWEB)

    Riccardi, Alberto; Brinkmann, Kai-Thomas; Di Pietro, Valentino [II. Physikalisches Institut, Justus-Liebig-Universitaet Giessen (Germany); Garbolino, Sara; Rivetti, Angelo; Rolo, Manuel [INFN Sezione di Torino, Torino (Italy); Collaboration: PANDA-Collaboration

    2015-07-01

    In nuclear detectors the information on the energy of the particle is usually obtained by measuring the amplitude of the signal delivered by the sensor. The low voltage power supply used in modern deep submicron technologies constrain the maximum dynamic range of the ADC. Still, the energy information can be obtained with time-based techniques, in which the energy is associated with the duration of the signal through the Time over Threshold method. This work is focused on the PANDA Micro Vertex Detector and explores the possibility of applying a time-based readout approach for the microstrip sensors. In PANDA, the strip system must cope with hit rates up to 50 kHz per channel. Therefore, the front-end output must be relatively short, this implies that the clock resolution is not enough to measure the signal duration, so it is necessary to use a Time to Digital Converter. The front-end and the TDC structure are designed in a 0.11μm CMOS process. The TDC chosen is based on an analog clock interpolator because it combines good time resolution with a fairly simple implementation and low power consumption. In the presentation an overview of the analog part of the PASTA (PANDA strip ASIC) is presented.

  7. First images of a digital autoradiography system based on a Medipix2 hybrid silicon pixel detector.

    Science.gov (United States)

    Mettivier, Giovanni; Montesi, Maria Cristina; Russo, Paolo

    2003-06-21

    We present the first images of beta autoradiography obtained with the high-resolution hybrid pixel detector consisting of the Medipix2 single photon counting read-out chip bump-bonded to a 300 microm thick silicon pixel detector. This room temperature system has 256 x 256 square pixels of 55 microm pitch (total sensitive area of 14 x 14 mm2), with a double threshold discriminator and a 13-bit counter in each pixel. It is read out via a dedicated electronic interface and control software, also developed in the framework of the European Medipix2 Collaboration. Digital beta autoradiograms of 14C microscale standard strips (containing separate bands of increasing specific activity in the range 0.0038-32.9 kBq g(-1)) indicate system linearity down to a total background noise of 1.8 x 10(-3) counts mm(-2) s(-1). The minimum detectable activity is estimated to be 0.012 Bq for 36,000 s exposure and 0.023 Bq for 10,800 s exposure. The measured minimum detection threshold is less than 1600 electrons (equivalent to about 6 keV Si). This real-time system for beta autoradiography offers lower pixel pitch and higher sensitive area than the previous Medipix1-based system. It has a 14C sensitivity better than that of micro channel plate based systems, which, however, shows higher spatial resolution and sensitive area.

  8. The system of digital-image optical microscope in semiconductor particle detector development

    International Nuclear Information System (INIS)

    Han Lixiang; Li Zhankui; Jin Genming; Wang Zhusheng; Xiao Guoqing

    2009-01-01

    Optical microscopic detection is very important in the process of semiconductor particle detector development. A system of digital-image optical microscope has been constructed with rather low price, which performance is comparable with the moderate-level imports. The system mounts powerful dry objective, and a 2μm resolution could be achieved. Observations with bright and dark field, polarized light,and interference light can be carried out on it. The system have large area on-line monitor,and the photographic device can be controlled by PC. It can be used in the control of defects and contaminations, pattern test, identification of crystal backing, inspection of the smoothness and the flatness of the crystal surface. It can also be used in some precise procedures, such as test, assembly, packaging and repairing. The quality of the bond could be examined by observing the appearance of the bond point and the microscopic structure of the solder. The surface fluctuation can be precisely measured under the microscope with the technology of multi-beam interference. In the article, the application of this system for semiconductor particle detector development has been illustrated, and the construction information has been described in detail. (authors)

  9. 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)

  10. Should 3K zoom function be used for detection of pneumothorax in cesium iodide/amorphous silicon flat-panel detector radiographs presented on 1K-matrix soft copies?

    International Nuclear Information System (INIS)

    Herrmann, Karin A.; Zech, C.J.; Reiser, M.F.; Bonel, H.M.; Staebler, A.; Voelk, M.; Strotzer, M.

    2006-01-01

    The purpose of the study was to evaluate observer performance in the detection of pneumothorax with cesium iodide and amorphous silicon flat-panel detector radiography (CsI/a-Si FDR) presented as 1K and 3K soft-copy images. Forty patients with and 40 patients without pneumothorax diagnosed on previous and subsequent digital storage phosphor radiography (SPR, gold standard) had follow-up chest radiographs with CsI/a-Si FDR. Four observers confirmed or excluded the diagnosis of pneumothorax according to a five-point scale first on the 1K soft-copy image and then with help of 3K zoom function (1K monitor). Receiver operating characteristic (ROC) analysis was performed for each modality (1K and 3K). The area under the curve (AUC) values for each observer were 0.7815, 0.7779, 0.7946 and 0.7066 with 1K-matrix soft copies and 0.8123, 0.7997, 0.8078 and 0.7522 with 3K zoom. Overall detection of pneumothorax was better with 3K zoom. Differences between the two display methods were not statistically significant in 3 of 4 observers (p-values between 0.13 and 0.44; observer 4: p=0.02). The detection of pneumothorax with 3K zoom is better than with 1K soft copy but not at a statistically significant level. Differences between both display methods may be subtle. Still, our results indicate that 3K zoom should be employed in clinical practice. (orig.)

  11. A highly accurate wireless digital sun sensor based on profile detecting and detector multiplexing technologies

    Science.gov (United States)

    Wei, Minsong; Xing, Fei; You, Zheng

    2017-01-01

    The advancing growth of micro- and nano-satellites requires miniaturized sun sensors which could be conveniently applied in the attitude determination subsystem. In this work, a profile detecting technology based high accurate wireless digital sun sensor was proposed, which could transform a two-dimensional image into two-linear profile output so that it can realize a high update rate under a very low power consumption. A multiple spots recovery approach with an asymmetric mask pattern design principle was introduced to fit the multiplexing image detector method for accuracy improvement of the sun sensor within a large Field of View (FOV). A FOV determination principle based on the concept of FOV region was also proposed to facilitate both sub-FOV analysis and the whole FOV determination. A RF MCU, together with solar cells, was utilized to achieve the wireless and self-powered functionality. The prototype of the sun sensor is approximately 10 times lower in size and weight compared with the conventional digital sun sensor (DSS). Test results indicated that the accuracy of the prototype was 0.01° within a cone FOV of 100°. Such an autonomous DSS could be equipped flexibly on a micro- or nano-satellite, especially for highly accurate remote sensing applications.

  12. 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

  13. Clinical evaluation of digital angiographic system equipped with the Safire' flat-panel detector of a direct conversion type

    International Nuclear Information System (INIS)

    Miura, Yoshiaki; Miura, Yusuke; Goto, Keiichi

    2003-01-01

    This report presents a report on clinical evaluation of our newly developed flat-panel X-ray detector of a direct conversion type, designed to provide images of a resolution higher than, or at least equal to, that ensured by X-ray photographic films, in clinical digital X-ray cinematography. This new detector was named 'Safire' the acronym of 'Shimadzu advanced flat imaging receptor', emphasizing its high technological level, such as the capability to ensure high quality of images. The clinical evaluation of Shimadzu DIGITEX Premier digital angiography system, equipped with this new flat-panel X-ray detector of a direct conversion type, has been started in March, 2003, at the Kokura Memorial Hospital in Kyushu, Japan. (author)

  14. Radiographic enhancement and analysis system

    International Nuclear Information System (INIS)

    Schlosser, M.S.

    1981-01-01

    Radiographic image enhancement and analysis techniques are discussed as they apply to nondestructive inspection. A system is described which has been developed to enhance and quantitatively evaluate radiographic images using digital computer techniques. Some examples of typical applications are also presented as an introduction to this new inspection technique. (author)

  15. Radiographic evaluations

    International Nuclear Information System (INIS)

    Williams, J.L.

    1988-01-01

    The author describes how to: perform a systematic evaluation of a chest radiograph; state the classic radiographic description of hyaline membrane disease; list the conditions that cause hyperaeration and describe the radiologic feature of hyperaeration; describe the radiograph of a patient with a congenital diaphragmatic hernia; identify optimum placement of an endotracheal tube, gastric feeding tube, and umbilical artery catheter on a radiograph; differentiate between pulmonary interstitial air and hyaline membrane disease; select radiographic features that would indicate the presence of a tension pneumothorax; describe a lateral decubitus projection and state the type of problem it is most often used to identify; explain the procedure used in obtaining a lateral neck radiograph and list two problems that may require this view; and describe the radiograph of a patient with cystic fibrosis

  16. Chesneys' radiographic imaging. 5. ed.

    International Nuclear Information System (INIS)

    Ball, J.; Price, T.

    1989-01-01

    This new edition of Chesney and Chesney: Radiographic Imaging has been completely written by two new authors. The book reflects the change in emphasis in radiology from photographic processes towards electronic imaging methods. There is new material on image intensifiers and television imaging, digital imaging and digital subtractions. Analyses of the various characteristics of, and defects in, images on radiographs, xeroradiographs and the television screen are included. The methods, equipment and materials used to record the cathode ray tube image are described and there is new material on the principles of alternative diagnostic imaging techniques such as ultrasound, computed tomography and radionuclide imaging which provide cathode ray tube images. The book is primarily for student radiographers studying for the Diploma of the College of Radiographers, but radiographers studying for postdiplomate qualifications such as the Higher Diploma (HDCR) will also find the book helpful. (author)

  17. Development of a time-to-digital converter ASIC for the upgrade of the ATLAS Monitored Drift Tube detector

    Science.gov (United States)

    Wang, Jinhong; Liang, Yu; Xiao, Xiong; An, Qi; Chapman, John W.; Dai, Tiesheng; Zhou, Bing; Zhu, Junjie; Zhao, Lei

    2018-02-01

    The upgrade of the ATLAS muon spectrometer for the high-luminosity LHC requires new trigger and readout electronics for various elements of the detector. We present the design of a time-to-digital converter (TDC) ASIC prototype for the ATLAS Monitored Drift Tube (MDT) detector. The chip was fabricated in a GlobalFoundries 130 nm CMOS technology. Studies indicate that its timing and power dissipation characteristics meet the design specifications, with a timing bin variation of ±40 ps for all 48 TDC slices and a power dissipation of about 6.5 mW per slice.

  18. An in vitro radiographic analysis of the density of dental luting cements as measured by CCD-based digital radiography.

    Science.gov (United States)

    Antonijevic, Djordje; Jevremovic, Danimir; Jovanovic, Svetlana; Obradovic-Djuricic, Kosovka

    2012-05-01

    According to the ISO, the radiopacity of luting cements should be equal to or greater than that of aluminum. The aim of this in vitro study was to determine the radiopacity of 13 commercially available dental luting cements and compare them with human enamel and dentin. Five classes of luting cements were evaluated: zinc phosphate (Cegal N and Harvard Zinc Phosphate), zinc polycarboxylate (Harvard Polycarboxylate and Hoffmann's Carboxylate), glass ionomers (Ketac Cem Easymix, Ketac Cem Radiopaque, and Fuji I), resin-modified glass ionomer (Rely X Luting), and resin cements (Multilink Automix, Variolink II, Speed CEM, Rely X Unicem Automix, and three shades of Variolink Veneer). Tooth slices served as controls. Five specimens of each material measuring 8 mm in diameter and 1 mm thick were prepared and radiographed alongside tooth slices and an aluminum stepwedge using a Trophy RVG sensor. The radiopacity values were expressed in mm Al and analyzed by the ANOVA and Tukey tests (P cements examined except Variolink Veneer had significantly higher radiopacities than that of dentin. Rely X Unicem Automix, glass ionomer, and resin-modified glass-ionomer cements demonstrated radiopacities that were not significantly different with respect to enamel. Zinc phosphate, zinc polycarboxylate, and three of the resin cements presented radiopacity values that were significantly greater than that of enamel. Almost all the investigated materials presented an acceptable radiopacity. Radiopacity of dental cements seems to depend more on the presence of elements with high atomic numbers than on the type of the material.

  19. GELATIO: a general framework for modular digital analysis of high-purity Ge detector signals

    International Nuclear Information System (INIS)

    Agostini, M; Pandola, L; Zavarise, P; Volynets, O

    2011-01-01

    GELATIO is a new software framework for advanced data analysis and digital signal processing developed for the GERDA neutrinoless double beta decay experiment. The framework is tailored to handle the full analysis flow of signals recorded by high purity Ge detectors and photo-multipliers from the veto counters. It is designed to support a multi-channel modular and flexible analysis, widely customizable by the user either via human-readable initialization files or via a graphical interface. The framework organizes the data into a multi-level structure, from the raw data up to the condensed analysis parameters, and includes tools and utilities to handle the data stream between the different levels. GELATIO is implemented in C++. It relies upon ROOT and its extension TAM, which provides compatibility with PROOF, enabling the software to run in parallel on clusters of computers or many-core machines. It was tested on different platforms and benchmarked in several GERDA-related applications. A stable version is presently available for the GERDA Collaboration and it is used to provide the reference analysis of the experiment data.

  20. Fast digital envelope detector based on generalized harmonic wavelet transform for BOTDR performance improvement

    International Nuclear Information System (INIS)

    Yang, Wei; Yang, Yuanhong; Yang, Mingwei

    2014-01-01

    We propose a fast digital envelope detector (DED) based on the generalized harmonic wavelet transform to improve the performance of coherent heterodyne Brillouin optical time domain reflectometry. The proposed DED can obtain undistorted envelopes due to the zero phase-shift ideal bandpass filter (BPF) characteristics of the generalized harmonic wavelet (GHW). Its envelope average ability benefits from the passband designing flexibility of the GHW, and its demodulation speed can be accelerated by using a fast algorithm that only analyses signals of interest within the passband of the GHW with reduced computational complexity. The feasibility and advantage of the proposed DED are verified by simulations and experiments. With an optimized bandwidth, Brillouin frequency shift accuracy improvements of 19.4% and 11.14%, as well as envelope demodulation speed increases of 39.1% and 24.9%, are experimentally attained by the proposed DED over Hilbert transform (HT) and Morlet wavelet transform (MWT) based DEDs, respectively. Spatial resolution by the proposed DED is undegraded, which is identical to the undegraded value by HT-DED with an allpass filter characteristic and better than the degraded value by MWT-DED with a Gaussian BPF characteristic. (paper)

  1. GELATIO: a general framework for modular digital analysis of high-purity Ge detector signals

    Science.gov (United States)

    Agostini, M.; Pandola, L.; Zavarise, P.; Volynets, O.

    2011-08-01

    GELATIO is a new software framework for advanced data analysis and digital signal processing developed for the GERDA neutrinoless double beta decay experiment. The framework is tailored to handle the full analysis flow of signals recorded by high purity Ge detectors and photo-multipliers from the veto counters. It is designed to support a multi-channel modular and flexible analysis, widely customizable by the user either via human-readable initialization files or via a graphical interface. The framework organizes the data into a multi-level structure, from the raw data up to the condensed analysis parameters, and includes tools and utilities to handle the data stream between the different levels. GELATIO is implemented in C++. It relies upon ROOT and its extension TAM, which provides compatibility with PROOF, enabling the software to run in parallel on clusters of computers or many-core machines. It was tested on different platforms and benchmarked in several GERDA-related applications. A stable version is presently available for the GERDA Collaboration and it is used to provide the reference analysis of the experiment data.

  2. Radiographic testing

    International Nuclear Information System (INIS)

    Kuster, J.

    1978-01-01

    In view of great differencies in X-ray transmission it is more difficult to get optimum radiographs of plastics and especially of reinforced plastics than for example of metals. A procedure will be reported how to get with little effort optimum radiographs especially also in the range of long wave-length radiation corresponding 10 to 25 kV.P. (orig.) [de

  3. 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.

  4. Conversion into numerical form of radiographic images

    International Nuclear Information System (INIS)

    Cappabianca, C.; Della Rocca, A.B.; Ferriani, S.

    1986-01-01

    Radiographic means are widely used for non destructive testing. However, human and technological factors strongly influence reliability of the results and further use of these technique. Image Processing can help to overtake those difficulties if radiographic films are previously digitized. This paper shows methods and equipments used in this field. The system EDI (Enea Digital. Imagery) operating in Casaccia Energy Research Centre is described

  5. Measure by image analysis of industrial radiographs

    International Nuclear Information System (INIS)

    Brillault, B.

    1988-01-01

    A digital radiographic picture processing system for non destructive testing intends to provide the expert with computer tool, to precisely quantify radiographic images. The author describes the main problems, from the image formation to its characterization. She also insists on the necessity to define a precise process in order to automatize the system. Some examples illustrate the efficiency of digital processing for radiographic images [fr

  6. Comparison of the image quality of digital radiography system and film screen system - Radiologist' rating of the visibility of normal anatomic - Structures in chest PA, Skull radiograph and K. U. B

    International Nuclear Information System (INIS)

    Song, Kounn Sik; Kim, Young Goo; Lee, Jong Beum; Kim, Kun Sang

    1987-01-01

    Digital image acquisition and display is widely used in computed tomography, ultrasonography, digital subtraction angiography, nuclear medicine and magnetic resonance image. But most of the radiological examinations performed in radiology department are made by using conventional system. The development of the digital radiography system is essential if totally digitized radiology department is desired. The advantages of digitizing the radiographic information are usually discussed in terms of PACS (picture archiving and communication system), furthermore there are many other advantages such as contrast modification, spatial filtering subtraction and superimposition of the images through the image processing by computer. Currently several approaches are under development or in clinical use, the most promising approach is the use of imaging plate composed of photostimulate phosphors such as barium fluorohalide crystal read with a He-Ne laser to produce digital radiographic images. Another promising approach is scan projection radiography. The authors performed the clinical study of comparing the image qualities of digital radiography system using scanning laser luminescence (FCR) and conventional film-screen system in chest PA, skull radiography and K. U. B. in terms of the visibility of the normal anatomic structure rating those (qualities) on a scale of 0 to 3 and obtained the following results. Normal contrast digital images are comparable to conventional film-screen images, but the images of high frequency enhancement is far superior to conventional film-screen especially in peripherally located structures such as skin, subcutaneous fat, musculoskeletal systems, nasal bone, inner and outer table of the skull including the diploic space, paranasal sinuses, nasopharynx and larynx, trachea and main bronchi, mediastinal structures, retrocardiac and subphrenic vascular markings. Another promising aspects of digital radiography system is its wide exposure latitude and

  7. A triple-crystal phoswich detector with digital pulse shape discrimination for alpha/beta/gamma spectroscopy

    International Nuclear Information System (INIS)

    White, Travis L.; Miller, William H.

    1999-01-01

    Researchers at the University of Missouri - Columbia have developed a three-crystal phoswich detector coupled to a digital pulse shape discrimination system for use in alpha/beta/gamma spectroscopy. Phoswich detectors use a sandwich of scintillators viewed by a single photomultiplier tube to simultaneously detect multiple types of radiation. Separation of radiation types is based upon pulse shape difference among the phosphors, which has historically been performed with analog circuitry. The system uses a GaGe CompuScope 1012, 12 bit, 10 MHz computer-based oscilloscope that digitally captures the pulses from a phoswich detector and subsequently performs pulse shape discrimination with cross-correlation analysis. The detector, based partially on previous phoswich designs by Usuda et al., uses a 10 mg/cm 2 thick layer of ZnS(Ag) for alpha detection, followed by a 0.254 cm CaF 2 (Eu) crystal for beta detection, all backed by a 2.54 cm NaI(Tl) crystal for gamma detection. Individual energy spectra and count rate information for all three radiation types are displayed and updated periodically. The system shows excellent charged particle discrimination with an accuracy of greater than 99%. Future development will include a large area beta probe with gamma-ray discrimination, systems for low-energy photon detection (e.g. Bremsstrahlung or keV-range photon emissions), and other health physics instrumentation

  8. Low-silver radiographic detectors

    International Nuclear Information System (INIS)

    Troitskii, V.A.; Novikov, I.A.; Nikitin, V.F.; Krasnyi-Admoni, L.V.; Valevich, M.I.; Belyi, N.G.; Grom, V.S.

    1988-01-01

    X-ray films and screens with low silver content for use in weld radiography are reviewed and tested. Properties examined include image graininess, brightness, and sensitivity to x radiation. Results are given for radiography of steel 08Kh18N10T, St20, AMG-6, copper, and titanium welds. Processing techniques for low-silver films are discussed. It is established that films and screens containing little silver can replace many x-ray films containing much more silver. Monitoring methods were developed for the new materials to cover items in classes 3-7 on GOST 23075-78 when used with equipment of RUP-150/300-10 type or classes 4-7 with pulsed x-ray equipment

  9. Digital radiographic evaluation of mandibular third molar for age estimation in young adults and adolescents of South Indian population using modified Demirjian's method.

    Science.gov (United States)

    Mohammed, Rezwana Begum; Koganti, Ravichandra; Kalyan, Siva V; Tircouveluri, Saritha; Singh, Johar Rajvinder; Srinivasulu, Enganti

    2014-09-01

    In recent years, it has become increasingly important to determine the age of living people for a variety of reasons, including identifying criminal and legal responsibility and for many other social events such as birth certificate, marriage, beginning a job, joining the army and retirement. The aim of this study was to assess the developmental stages of mandibular third molar for estimation of dental age (DA) in different age groups and to evaluate the possible correlation between DA and chronological age (CA) in South Indian population. Digital orthopantomography of 330 subjects (165 males, 165 females) who fit the study and the criteria were obtained. Assessment of mandibular third molar development was performed using Demirjian et al., modified method and DA was assessed using tooth specific stages. The present study showed a significant correlation between DA and CA in both males and females. Third molar development commenced around 9 years and root completion takes place around 18.9 years in males and in females 9 years and 18.6 years respectively. Demirjian modified method underestimated the mean age of males by 0.8 years and females by 0.5 years and also showed that females mature earlier than males in selected population. Digital radiographic assessment of mandibular third molar development can be used to generate mean DA using Demirjian modified method and also the estimated age range for an individual of unknown CA. Since the Demirjian method is based on French-Canadian population, to enhance the accuracy of forensic age estimates based on third molar development, the use of population-specific standards is recommended.

  10. 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

  11. 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)

  12. WE-G-204-08: Optimized Digital Radiographic Technique for Lost Surgical Devices/Needle Identification

    International Nuclear Information System (INIS)

    Gorman, A; Seabrook, G; Brakken, A; Dubois, M; Marn, C; Wilson, C; Jacobson, D; Liu, Y

    2015-01-01

    Purpose: Small surgical devices and needles are used in many surgical procedures. Conventionally, an x-ray film is taken to identify missing devices/needles if post procedure count is incorrect. There is no data to indicate smallest surgical devices/needles that can be identified with digital radiography (DR), and its optimized acquisition technique. Methods: In this study, the DR equipment used is a Canon RadPro mobile with CXDI-70c wireless DR plate, and the same DR plate on a fixed Siemens Multix unit. Small surgical devices and needles tested include Rubber Shod, Bulldog, Fogarty Hydrogrip, and needles with sizes 3-0 C-T1 through 8-0 BV175-6. They are imaged with PMMA block phantoms with thickness of 2–8 inch, and an abdomen phantom. Various DR techniques are used. Images are reviewed on the portable x-ray acquisition display, a clinical workstation, and a diagnostic workstation. Results: all small surgical devices and needles are visible in portable DR images with 2–8 inch of PMMA. However, when they are imaged with the abdomen phantom plus 2 inch of PMMA, needles smaller than 9.3 mm length can not be visualized at the optimized technique of 81 kV and 16 mAs. There is no significant difference in visualization with various techniques, or between mobile and fixed radiography unit. However, there is noticeable difference in visualizing the smallest needle on a diagnostic reading workstation compared to the acquisition display on a portable x-ray unit. Conclusion: DR images should be reviewed on a diagnostic reading workstation. Using optimized DR techniques, the smallest needle that can be identified on all phantom studies is 9.3 mm. Sample DR images of various small surgical devices/needles available on diagnostic workstation for comparison may improve their identification. Further in vivo study is needed to confirm the optimized digital radiography technique for identification of lost small surgical devices and needles

  13. The effect of amorphous selenium detector thickness on dual-energy digital breast imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yue-Houng, E-mail: yuehoung.hu@gmail.com; Zhao, Wei [Department of Radiology, State University of New York at Stony Brook, L-4 120 Health Sciences Center, Stony Brook, New York 11794-8460 (United States)

    2014-11-01

    Purpose: Contrast enhanced (CE) imaging techniques for both planar digital mammography (DM) and three-dimensional (3D) digital breast tomosynthesis (DBT) applications requires x-ray photon energies higher than the k-edge of iodine (33.2 keV). As a result, x-ray tube potentials much higher (>40 kVp) than those typical for screening mammography must be utilized. Amorphous selenium (a-Se) based direct conversion flat-panel imagers (FPI) have been widely used in DM and DBT imaging systems. The a-Se layer is typically 200 μm thick with quantum detective efficiency (QDE) >87% for x-ray energies below 26 keV. However, QDE decreases substantially above this energy. To improve the object detectability of either CE-DM or CE-DBT, it may be advantageous to increase the thickness (d{sub Se}) of the a-Se layer. Increasing the d{sub Se} will improve the detective quantum efficiency (DQE) at the higher energies used in CE imaging. However, because most DBT systems are designed with partially isocentric geometries, where the gantry moves about a stationary detector, the oblique entry of x-rays will introduce additional blur to the system. The present investigation quantifies the effect of a-Se thickness on imaging performance for both CE-DM and CE-DBT, discussing the effects of improving photon absorption and blurring from oblique entry of x-rays. Methods: In this paper, a cascaded linear system model (CLSM) was used to investigate the effect of d{sub Se} on the imaging performance (i.e., MTF, NPS, and DQE) of FPI in CE-DM and CE-DBT. The results from the model are used to calculate the ideal observer signal-to-noise ratio, d′, which is used as a figure-of-merit to determine the total effect of increasing d{sub Se} for CE-DM and CE-DBT. Results: The results of the CLSM show that increasing d{sub Se} causes a substantial increase in QDE at the high energies used in CE-DM. However, at the oblique projection angles used in DBT, the increased length of penetration through a

  14. Method for taking X radiographs

    International Nuclear Information System (INIS)

    Orth, G.

    1983-01-01

    The method is aimed at obtaining X radiographs of any human organ with the aid of an X-ray-shadowless radiation detector of a dose measuring device, which is arranged between patient and imaging system, and of a controlling microprocessor system, so that the image-forming parameters are automatically adjusted to the specific properties of the patient. This procedure minimices the efforts in preparing the radiograph and the radiation exposure of the patient

  15. Radiographic positioning

    International Nuclear Information System (INIS)

    Eisenberg, R.L.; Dennis, C.A.; May, C.

    1989-01-01

    This book concentrates on the routine radiographic examinations commonly performed. It details the wide variety of examinations possible and their place in initial learning and in the radiology department as references for those occasions when an unusual examination is requested. This book provides information ranging from basic terminology to skeletal positioning to special procedures. Positions are discussed and supplemented with a picture of a patient, the resulting radiograph, and a labeled diagram. Immobilization and proper shielding of the patient are also shown

  16. Radiographic Test

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H.J; Yang, S.H. [Korea Electric Power Research Institute, Taejon (Korea)

    2002-07-01

    This report contains theory, procedure technique and interpretation of radiographic examination and written for whom preparing radiographic test Level II. To determine this baseline of technical competence in the examination, the individual must demonstrate a knowledge of radiography physics, radiation safety, technique development, radiation detection and measurement, facility design, and the characteristics of radiation-producing devices and their principles of operation. (author) 98 figs., 23 tabs.

  17. Coincidence measurements in α/β/γ spectrometry with phoswich detectors using digital pulse shape discrimination analysis

    International Nuclear Information System (INIS)

    Celis, B. de; Fuente, R. de la; Williart, A.; Celis Alonso, B. de

    2007-01-01

    A novel system has been developed for the detection of low radioactivity levels using coincidence techniques. The device combines a phoswich detector for α/β/γ ray recognition with a fast digital card for electronic pulse analysis. The detector is able to discriminate different types of radiation in a mixed α/β/γ field and can be used in a coincidence mode by identifying the composite signal produced by the simultaneous detection of β particles in a plastic scintillator and γ rays in an NaI(Tl) scintillator. Use of a coincidence technique with phoswich detectors was proposed recently to verify the Nuclear Test Ban Treaty, which made it necessary to monitor the low levels of xenon radioisotopes produced by underground nuclear explosions. Previous studies have shown that combining CaF 2 (Eu) for β ray detection and NaI(Tl) for γ ray detection makes it difficult to identify the coincidence signals because of the similar fluorescence decay times of the two scintillators. With the device proposed here, it is possible to identify the coincidence events owing to the short fluorescence decay time of the plastic scintillator. The sensitivity of the detector may be improved by employing liquid scintillators, which allow low radioactivity levels from actinides to be measured when present in environmental samples. The device developed is simpler to use than conventional coincidence equipment because it uses a single detector and electronic circuit, and it offers fast and precise analysis of the coincidence signals by employing digital pulse shape analysis

  18. Digital signal processing for a thermal neutron detector using ZnS(Ag):{sup 6}LiF scintillating layers read out with WLS fibers and SiPMs

    Energy Technology Data Exchange (ETDEWEB)

    Mosset, J.-B., E-mail: jean-baptiste.mosset@psi.ch; Stoykov, A.; Greuter, U.; Hildebrandt, M.; Schlumpf, N.

    2016-07-11

    We present a digital signal processing system based on a photon counting approach which we developed for a thermal neutron detector consisting of ZnS(Ag):{sup 6}LiF scintillating layers read out with WLS fibers and SiPMs. Three digital filters have been evaluated: a moving sum, a moving sum after differentiation and a digital CR-RC{sup 4} filter. The performances of the detector with these filters are presented. A full analog signal processing using a CR-RC{sup 4} filter has been emulated digitally. The detector performance obtained with this analog approach is compared with the one obtained with the best performing digital approach. - Highlights: • Application of digital signal processing for a SiPM-based ZnS:6LiF neutron detector. • Optimisation of detector performances with 3 different digital filters. • Comparison with detector performances with a full analog signal processing.

  19. 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...

  20. Measurement of the energy spectrum of {sup 252}Cf fission fragments using nuclear track detectors and digital image processing

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa, G.; Golzarri, J. I. [UNAM, Instituto de Fisica, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Castano, V. M. [UNAM, Centro de Fisica Aplicada y Tecnologia Avanzada, Boulevard Juriquilla 3001, Santiago de Queretaro, 76230 Queretaro (Mexico); Gaso, I. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Mena, M.; Segovia, N. [UNAM, Instituto de Geofisica, Circuito de la Investigacion Cientifica, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2010-02-15

    The energy spectrum of {sup 252}Cf fission fragments was measured using nuclear track detectors and digital image analysis system. The detection material was fused silica glass. The detectors were chemically etched in an 8% HF solution. After experimenting with various etching time, it was found that the best resolution of the track diameter distribution was obtained after 30 minutes of etching. Both Gaussian and Lorentzian curves were fit to the track diameter distribution histograms and used to determine the basic parameters of the distribution of the light (N{sub L}) and heavy (N{sub H}) formed peaks and the minimum of the central valley (N{sub V}). Advantages of the method presented here include the fully-automated analysis process, the low cost of the nuclear track detectors and the simplicity of the nuclear track method. The distribution resolution obtained by this method is comparable with the resolution obtained by electronic analysis devices. The descriptive variables calculated were very close to those obtained by other methods based on the use of semiconductor detectors. (Author)

  1. A digital X-ray imaging system based on silicon strip detectors working in edge-on configuration

    Energy Technology Data Exchange (ETDEWEB)

    Bolanos, L. [CEADEN, Calle 30 502 e/ 5ta y 7ma Avenida, Playa, Ciudad Habana (Cuba); Boscardin, M. [IRST, Fondazione Bruno Kessler, Via Sommarive 18, Povo, 38100 Trento (Italy); Cabal, A.E. [CEADEN, Calle 30 502 e/ 5ta y 7ma Avenida, Playa, Ciudad Habana (Cuba); Diaz, M. [InSTEC, Ave. Salvador Allende esq. Luaces, Quinta de los Molinos, Ciudad Habana (Cuba); Grybos, P.; Maj, P. [Faculty of Electrical Engineering, Automatics, Computer Science and Electronics, Department of Measurement and Instrumentation, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Cracow (Poland); Prino, F. [Istituto Nazionale di Fisica Nucleare, Sezione di Torino, Via P. Giuria 1, 10125 Torino (Italy); Ramello, L. [Dipartimento di Scienze e Tecnologie Avanzate, Universita del Piemonte Orientale, Via T. Michel 11, 15100 Alessandria (Italy)], E-mail: luciano.ramello@mfn.unipmn.it; Szczygiel, R. [Faculty of Electrical Engineering, Automatics, Computer Science and Electronics, Department of Measurement and Instrumentation, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Cracow (Poland)

    2009-09-21

    We present the energy resolution and imaging performance of a digital X-ray imaging system based on a 512-strip silicon strip detector (SSD) working in the edge-on configuration. The SSDs tested in the system are 300 {mu}m thick with 1 or 2-cm-long strips and 100 {mu}m pitch. To ensure a very small dead area of the SSD working in edge-on configuration, the detector is cut perpendicular to the strips at a distance of only 20 {mu}m from the end of the strips. The 512-strip silicon detector is read out by eight 64-channel integrated circuits called DEDIX [Grybos et al., IEEE Trans. Nucl. Sci. NS-54 (2007) 1207]. The DEDIX IC operates in a single photon counting mode with two independent amplitude discriminators per channel. The readout electronic channel connected to a detector with effective input capacitance of about 2 pF has an average equivalent noise charge (ENC) of about 163 el. rms and is able to count 1 Mcps of average rate of input pulses. The system consisting of 512 channels has an excellent channel-to-channel uniformity-the effective threshold spread calculated to the charge-sensitive amplifier inputs is 12 el. rms (at one sigma level). With this system a few test images of a phantom have been taken in the 10-30 keV energy range.

  2. A comparative analysis of OTF, NPS, and DQE in energy integrating and photon counting digital x-ray detectors

    International Nuclear Information System (INIS)

    Acciavatti, Raymond J.; Maidment, Andrew D. A.

    2010-01-01

    is a binary function given as zero or unity everywhere. In analyzing the model detector with Gaussian blurring, the difference in NPS and DQE between the two detector types is found to increase with the blurring of the x-ray converter. Ultimately, the expression for the additive white noise of the photon counter is compared against the expression for electronic noise and secondary quantum noise in an energy integrator. Thus, a method is provided to determine the average secondary quanta that the energy integrator must produce for each x ray to have superior DQE to a photon counter with the same PSF. Conclusions: This article develops analytical models of OTF, NPS, and DQE for energy integrating and photon counting digital x-ray detectors. While many subtleties of real imaging systems have not been modeled, this work is illustrative in demonstrating an additive source of white noise in photon counting detectors which has not yet been described in the literature. One benefit of this analysis is a framework for determining the average secondary quanta that an energy integrating detector must produce for each x ray to have superior DQE to competing photon counting technology.

  3. Evaluating x-ray detectors for radiographic applications: A comparison of nSCdS:Ag with Gd sub 2 O sub 2 S:Tb and Y sub 2 O sub 2 S:Tb screens

    CERN Document Server

    Kandarakis, I; Panayiotakis, G S; Nomicos, C D

    1997-01-01

    ZnSCdS:Ag was evaluated as a radiographic image receptor and was compared with Gd sub 2 O sub 2 S:Tb and Y sub 2 O sub 2 S:Tb phosphors often used in radiography. The valuation of a radiographic receptor was modelled as a three-step process: i) determination of light output intensity as related to the input radiation dose, (ii) determination of visible light characteristics with respect to radiographic optical detectors, and (iii) determination of image information transfer efficiency. The light intensity emitted per unit of x-ray exposure rate was measured and theoretically calculated for laboratory prepared screens with coating thicknesses from 20 to 220 mg cm sup - sup 2 and tube voltages rom 50 to 250 kVp. ZnSCdS:Ag light intensity was higher than that of d sub 2 O sub 2 S:Tb or Y sub 2 O sub 2 S:Tb for tube voltages less than 70 and 80 kVp respectively. ZnSCdS:Ag displayed the highest x-ray to light conversion efficiency (0.207) and had optical properties close to those of Gd sub 2 O sub 2 S:Tb nd Y sub ...

  4. Digital instrumentation and management of dead time: first results on a NaI well-type detector setup.

    Science.gov (United States)

    Censier, B; Bobin, C; Bouchard, J; Aubineau-Lanièce, I

    2010-01-01

    The LNE-LNHB is engaged in a development program on digital instrumentation, the first step being the instrumentation of a NaI well-type detector set-up. The prototype acquisition card and its technical specifications are presented together with the first comparison with the classical NIM-based acquisition chain, for counting rates up to 100 kcps. The digital instrumentation is shown to be counting-loss free in this range. This validates the main option adopted in this project, namely the implementation of an extending dead time with live-time measurement already successfully used in the MTR2 NIM module developed at LNE-LNHB. Copyright 2010. Published by Elsevier Ltd.

  5. First Tests of a New Fast Waveform Digitizer for PMT Signal Read-out from Liquid Argon Dark Matter Detectors

    Science.gov (United States)

    Szelc, A. M.; Canci, N.; Cavanna, F.; Cortopassi, A.; D'Incecco, M.; Mini, G.; Pietropaolo, F.; Romboli, A.; Segreto, E.; Acciarri, R.

    A new generation Waveform Digitizer board as been recently made available on the market by CAEN. The new board CAEN V1751 with 8 Channels per board, 10 bit, 1 GS/s Flash ADC Waveform Digitizer (or 4 channel, 10 bit, 2 GS/s Flash ADC Waveform Digitizer -Dual Edge Sampling mode) with threshold and Auto-Trigger capabilities provides an ideal (relatively low-cost) solution for reading signals from liquid Argon detectors for Dark Matter search equipped with an array of PMTs for the detection of scintillation light. The board was extensively used in real experimental conditions to test its usefulness for possible future uses and to compare it with a state of the art digital oscilloscope. As results, PMT Signal sampling at 1 or 2 GS/s is appropriate for the reconstruction of the fast component of the signal scintillation in Argon (characteristic time of about 4 ns) and the extended dynamic range, after a small customization, allows for the detection of signals in the range of energy needed. The bandwidth is found to be adequate and the intrinsic noise is very low.

  6. 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

  7. Animal radiographs

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    This chapter presents historical x rays of a wide variety of animals taken within 5 years of the discovery of x radiation. Such photos were used as tests or as illustrations for radiographic publications. Numerous historical photographs are included. 10 refs

  8. Visual grading analysis of digital neonatal chest phantom X-ray images: Impact of detector type, dose and image processing on image quality.

    Science.gov (United States)

    Smet, M H; Breysem, L; Mussen, E; Bosmans, H; Marshall, N W; Cockmartin, L

    2018-07-01

    To evaluate the impact of digital detector, dose level and post-processing on neonatal chest phantom X-ray image quality (IQ). A neonatal phantom was imaged using four different detectors: a CR powder phosphor (PIP), a CR needle phosphor (NIP) and two wireless CsI DR detectors (DXD and DRX). Five different dose levels were studied for each detector and two post-processing algorithms evaluated for each vendor. Three paediatric radiologists scored the images using European quality criteria plus additional questions on vascular lines, noise and disease simulation. Visual grading characteristics and ordinal regression statistics were used to evaluate the effect of detector type, post-processing and dose on VGA score (VGAS). No significant differences were found between the NIP, DXD and CRX detectors (p>0.05) whereas the PIP detector had significantly lower VGAS (pProcessing did not influence VGAS (p=0.819). Increasing dose resulted in significantly higher VGAS (plevels but not image post-processing changes. VGA showed a DAK/image value above which perceived IQ did not improve, potentially useful for commissioning. • A VGA study detects IQ differences between detectors and dose levels. • The NIP detector matched the VGAS of the CsI DR detectors. • VGA data are useful in setting initial detector air kerma level. • Differences in NNPS were consistent with changes in VGAS.

  9. 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).

  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. A radiographic analysis of implant component misfit.

    LENUS (Irish Health Repository)

    Sharkey, Seamus

    2011-07-01

    Radiographs are commonly used to assess the fit of implant components, but there is no clear agreement on the amount of misfit that can be detected by this method. This study investigated the effect of gap size and the relative angle at which a radiograph was taken on the detection of component misfit. Different types of implant connections (internal or external) and radiographic modalities (film or digital) were assessed.

  12. Practical measurement of radiation dose in pediatric radiology: use of the dose-area product on digital fluoroscopy and neonatal chest radiographs

    International Nuclear Information System (INIS)

    Chateil, J.F.; Rouby, C.; Brun, M.; Labessan, C.; Diard, F.

    2004-01-01

    Purpose. Control of radiation dose in pediatric radiology requires knowledge of the reference levels for all examinations. These data are useful for daily quality assessment, but are not perfectly known for some radiographic examinations. The purpose of our study was to evaluate the dose related to voiding cysto-urethrograms (VCUG), upper GI (UGI) and intravenous urography (IVU). Neonatal chest radiographs in the intensive care unit were also evaluated. Material and methods. For examinations with contrast material (478VCUG, 220UGI, 80IVU), the children were divided in groups based on their weight, from 5 to 30 Kg. Measurements were performed using an ionization chamber and expressed with the-dose-area product (DAP). For chest radiographs, a direct measurement of the entrance-skin dose was performed, with secondary calculation of the DAP. Results. For-VCUGs, the DAP ranged between 42.89 cGy.cm 2 and 125.41 cGy.cm 2 . The range was between 76.43, and 150.62 cGy.cm 2 for UGIs and between 49.06 and 83.33 cGy.cm 2 for IVUs. For neonate chest radiographs, DAP calculations were between 0.29 and 0.99 cGy.cm 2 . Conclusion. These values represent our reference doses. They allow continuous monitoring of our radiographic technical parameters and radiographic equipment and help to correct and improve them if necessary. (author)

  13. Test of digital neutron–gamma discrimination with four different photomultiplier tubes for the NEutron Detector Array (NEDA)

    Energy Technology Data Exchange (ETDEWEB)

    Luo, X.L., E-mail: luo.xiaoliang@physics.uu.se [Department of Instrument Science and Technology, College of Mechatronics and Automation, National University of Defense Technology, Changsha (China); Department of Physics and Astronomy, Uppsala University, SE-75120 Uppsala (Sweden); Modamio, V. [INFN, Laboratori Nazionali di Legnaro, I-35020 Legnaro, Padova (Italy); Nyberg, J. [Department of Physics and Astronomy, Uppsala University, SE-75120 Uppsala (Sweden); Valiente-Dobón, J.J. [INFN, Laboratori Nazionali di Legnaro, I-35020 Legnaro, Padova (Italy); Nishada, Q. [Department of Physics and Astronomy, Uppsala University, SE-75120 Uppsala (Sweden); Angelis, G. de [INFN, Laboratori Nazionali di Legnaro, I-35020 Legnaro, Padova (Italy); Agramunt, J. [IFIC-CSIC, University of Valencia, Valencia (Spain); Egea, F.J. [IFIC-CSIC, University of Valencia, Valencia (Spain); Faculty of Engineering and Natural Sciences, Istanbul Sabahattin Zaim University, Istanbul (Turkey); Erduran, M.N.; Ertürk, S. [Nigde Universitesi, Fen-Edebiyat Falkültesi, Fizik Bölümü, Nigde (Turkey); France, G. de [GANIL, CEA/DSAM and CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 05 (France); Gadea, A. [IFIC-CSIC, University of Valencia, Valencia (Spain); González, V. [Department of Electronic Engineering, University of Valencia, E-46071 Valencia (Spain); Hüyük, T. [IFIC-CSIC, University of Valencia, Valencia (Spain); Jaworski, G. [Faculty of Physics, Warsaw University of Technology, ul. Koszykowa 75, 00-662 Warszawa (Poland); Heavy Ion Laboratory, University of Warsaw, ul. Pasteura 5A, 02-093 Warszawa (Poland); Moszyński, M. [Heavy Ion Laboratory, University of Warsaw, ul. Pasteura 5A, 02-093 Warszawa (Poland); National Centre for Nuclear Research, A. Soltana 7, PL 05-400 Otwock-Swierk (Poland); and others

    2014-12-11

    A comparative study of the neutron–γ discrimination performance of a liquid scintillator detector BC501A coupled to four different 5 in. photomultiplier tubes (ET9390kb, R11833-100, XP4512 and R4144) was carried out. Both the Charge Comparison method and the Integrated Rise-Time method were implemented digitally to discriminate between neutrons and γ rays emitted by a {sup 252}Cf source. In both methods, the neutron–γ discrimination capabilities of the four photomultiplier tubes were quantitatively compared by evaluating their figure-of-merit values at different energy regions between 50 keVee and 1000 keVee. Additionally, the results were further verified qualitatively using time-of-flight to distinguish γ rays and neutrons. The results consistently show that photomultiplier tubes R11833-100 and ET9390kb generally perform best regarding neutron–γ discrimination with only slight differences in figure-of-merit values. This superiority can be explained by their relatively higher photoelectron yield, which indicates that a scintillator detector coupled to a photomultiplier tube with higher photoelectron yield tends to result in better neutron–γ discrimination performance. The results of this work will provide reference for the choice of photomultiplier tubes for future neutron detector arrays like NEDA.

  14. Linear density analysis of bone repair in rats using digital direct radiograph Análise de densidade linear para reparo ósseo em ratos utilizando radiografia digital direta

    Directory of Open Access Journals (Sweden)

    Ricardo de Oliveira Bozzo

    2004-12-01

    Full Text Available The objective of this study was to assess bone density measurements for analysis of repairing fractures in rats using direct digital radiography under Dexamethasone effects. Thirty (30 young adult male Wistar rats were used, with an average weight of 200g, which were submitted to general anesthetics by ethyl ether. One rib of each animal was fractured by surgical technique. The rats were divided into 2 groups, named Control group - intraperitoneal administration of saline solution 1 hour prior to operation, and Group 1: intraperitoneal administration of Dexamethasone 0.1mg/Kg of weight 1 hour prior to operation, and two postoperative doses every 12 hours. The animals were sacrificed at 2, 3, 4, 7 and 14 days. The parts containing the hemi-thorax with the fractured rib were removed and submitted to direct digital radiography, where the linear density of the two extremities of the fracture were analyzed by the Digora System. The results showed that in the control group and in Group 1 there was a gradual and significant increase in linear density. The method used made it feasible to supply data that were statistically significant in assessing the gain in bone density during the period of time analyzed. In conclusion, direct digital radiograph is useful for bone density analysis for fracture repairing. The dose of Dexamethasone was not sufficient to alter the gain in bone density at the extremities of fracture.O objetivo deste estudo foi analisar densidade linear utilizando o sistema de radiografia digital direta intrabucal para verificar o ganho de densidade óssea em fraturas de ratos sob os efeitos da Dexametasona. Trinta (30 ratos Wistar machos, adultos jóvens de 200 g em média foram usados. Os animais foram submetidos á anestesia geral por inalação de éter etílico e 01 costela de cada animal foi fraturada através de técnica cirúrgica. Os ratos foram divididos em grupos de 03 repetições para cada grupo em cada período de tempo

  15. Digital approach to high-resolution pulse processing for semiconductor detectors

    International Nuclear Information System (INIS)

    Georgiev, A.; Buchner, A.; Gast, W.; Lieder, R.M.

    1992-01-01

    A new design philosophy for processing signals produced by high resolution, large volume semiconductor detectors is described. These detectors, to be used in the next generation of spectrometer arrays for nuclear research (i.e. EUROBALL, etc.), present a set of problems like resolution degradation due to charge trapping and ballistic defect effects, low resolution at a high count rate, poor long term stability, etc. To solve these problems, a new design approach has been developed, including reconstruction of the event charge, providing a pure triangular residual function, and suppressing low frequency noise. 5 refs., 4 figs

  16. Digital approach to high-resolution pulse processing for semiconductor detectors

    Energy Technology Data Exchange (ETDEWEB)

    Georgiev, A [Sofia Univ. (Bulgaria); Buchner, A [Forschungszentrum Rossendorf (Germany); Gast, W; Lieder, R M [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Stein, J [Target System Electronic GmbH, Solingen, (Germany)

    1992-08-01

    A new design philosophy for processing signals produced by high resolution, large volume semiconductor detectors is described. These detectors, to be used in the next generation of spectrometer arrays for nuclear research (i.e. EUROBALL, etc.), present a set of problems like resolution degradation due to charge trapping and ballistic defect effects, low resolution at a high count rate, poor long term stability, etc. To solve these problems, a new design approach has been developed, including reconstruction of the event charge, providing a pure triangular residual function, and suppressing low frequency noise. 5 refs., 4 figs.

  17. Comparison of Findings from Oblique Radiographs of the Raised Limb with Those of the Weight-bearing Limb for Selected Diseases of the Equine Digit

    Directory of Open Access Journals (Sweden)

    J. Šterc

    2007-01-01

    Full Text Available In the present study, the radiographic examination of the distal and proximal interphalangeal joints was performed in 43 randomly selected horses. A total of 86 forelimbs were examined. On the forelimbs, dorsolateral-palmaromedial, and dorsomedial-palmarolateral oblique views were performed. The oblique views were performed on raised limbs placed in a navicular block and on weight-bearing limbs placed on a pedestal made at the equine clinic. In total, 688 dorsolateral-palmaromedial and dorsomedial-palmarolateral views were taken. During the evaluation of the radiographs we focused on the detection of signs of degenerative joint disease of the distal and proximal iterphalangeal joints, and the detection of new bone formation in the phalanx regions, not associated with a disease of the distal or proximal interphalangeal joints. Based on the radiographic signs visible on these views, we diagnosed 9 cases of degenerative joint disease of the distal intraphalangeal joint, 13 cases of the degenerative joint disease of the proximal intraphalangeal joint and 21 cases of new bone formation in the phalanx regions. These signs were observed in 253 of 688 oblique views. Positive radiographic findings of the above-mentioned disorders were shown on 127 oblique views of the raised limb placed in the navicular block and 126 oblique views of the weight-bearing limb placed on the pedestal we made. When 128 oblique views of the weight-bearing limb (placed on the pedestal were compared with those of the raised limb (in the navicular block, there were different radiographic findings in three cases only. The differences in detection rates of radiographic signs between different type views showed no statistical significance (p ≥ 0.05. Therefore we assume that the pedestal we made can be routinely used for the radiographic examination of the distal and proximal interphalangeal joints on DL-PM and DM-PL oblique views, as part of pre-purchase examination or diagnosis

  18. Performance evaluation of a sub-millimeter spatial resolution PET detector module using a digital silicon photomultiplier coupled LGSO array

    Energy Technology Data Exchange (ETDEWEB)

    Leem, Hyun Tae [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Choi, Yong, E-mail: ychoi@sogang.ac.kr [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Kim, Kyu Bom; Lee, Sangwon [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Yamamoto, Seiichi [Department of Medical Technology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Yeom, Jung-Yeol, E-mail: jungyeol@korea.ac.kr [School of Biomedical Engineering, Korea University, Seoul (Korea, Republic of)

    2017-02-21

    In positron emission tomography (PET) for breast, brain and small animal imaging, the spatial resolution of a PET detector is crucial to obtain high quality PET images. In this study, a PET detector for sub-millimeter spatial resolution imaging purpose was assembled using 4×4 pixels of a digital silicon photomultiplier (dSiPM, DPC-3200-22-44, Philips) coupled with a 15×15 LGSO array with BaSO{sub 4} reflector, and a 1 mm thick acrylic light guide for light distribution between the dSiPM pixels. The active area of each dSiPM pixel was 3.2×3.9 mm{sup 2} and the size of each LGSO scintillator element was 0.7×0.7×6 mm{sup 3}. In this paper, we experimentally demonstrated the performance of the PET detector by measuring the energy resolution, 2D flood map, peak to valley (P/V) ratio, and coincidence resolving time (CRT). All measurements were performed at a temperature of 10±1 ℃. The average energy resolution was 15.6% (without correcting for saturation effects) at 511 keV and the best CRT was 242±5 ps. The 2D flood map obtained with an energy window of 400–600 keV demonstrated clear identification of all pixels, and the average P/V ratio of the X- and Y-directions were 7.31 and 7.81, respectively. This study demonstrated that the PET detector could be suitable for application in high resolution PET while achieving good timing resolution.

  19. Bone loss in unclassified polyarthritis and early rheumatoid arthritis is better detected by digital x ray radiogrammetry than dual x ray absorptiometry: relationship with disease activity and radiographic outcome

    DEFF Research Database (Denmark)

    Jensen, T; Klarlund, Mette; Hansen, M

    2004-01-01

    OBJECTIVE: To compare changes in regional bone mineral density (BMD) of the metacarpal joints measured by dual x ray absorptiometry (DXA) and digital x ray radiogrammetry (DXR) in relation to disease activity and radiographic outcome in a two year follow up study of patients with early RA...... polyarthritis. The patients with RA were divided into groups according to mean disease activity, average glucocorticoid dose, and MRI and x ray detected bone erosions in the hands. Clinical and biochemical measurements were made every month and an x ray examination of the hands and BMD of the metacarpal joints...

  20. Analysis of the imaging performance in indirect digital mammography detectors by linear systems and signal detection models

    International Nuclear Information System (INIS)

    Liaparinos, P.; Kalyvas, N.; Kandarakis, I.; Cavouras, D.

    2013-01-01

    Purpose: The purpose of this study was to provide an analysis of imaging performance in digital mammography, using indirect detector instrumentation, by combining the Linear Cascaded Systems (LCS) theory and the Signal Detection Theory (SDT). Observer performance was assessed, by examining frequently employed detectors, consisting of phosphor-based X-ray converters (granular Gd 2 O 2 S:Tb and structural CsI:Tl), coupled with the recently introduced complementary metal-oxide-semiconductor (CMOS) sensor. By applying combinations of various irradiation conditions (filter-target and exposure levels at 28 kV) on imaging detectors, our study aimed to find the optimum system set-up for digital mammography. For this purpose, the signal to noise transfer properties of the medical imaging detectors were examined for breast carcinoma detectability. Methods: An analytical model was applied to calculate X-ray interactions within software breast phantoms and detective media. Modeling involved: (a) three X-ray spectra used in digital mammography: 28 kV Mo/Mo (Mo: 0.030 mm), 28 kV Rh/Rh (Rh: 0.025 mm) and 28 kV W/Rh (Rh: 0.060 mm) at different entrance surface air kerma (ESAK) of 3 mGy and 5 mGy, (b) a 5 cm thick Perspex software phantom incorporating a small Ca lesion of varying size (0.1–1 cm), and (c) two 200 μm thick phosphor-based X-ray converters (Gd2O2S:Tb, CsI:Tl), coupled to a CMOS based detector of 22.5 μm pixel size. Results: Best (lowest) contrast threshold (CT) values were obtained with the combination: (i) W/Rh target-filter, (ii) 5 mGy (ESAK), and (iii) CsI:Tl-CMOS detector. For lesion diameter 0.5 cm the CT was found improved, in comparison to other anode/filter combinations, approximately 42% than Rh/Rh and 55% than Mo/Mo, for small sized carcinoma (0.1 cm) and approximately 50% than Rh/Rh and 125% than Mo/Mo, for big sized carcinoma (1 cm), considering 5 mGy X-ray beam. By decreasing lesion diameter and thickness, a limiting CT (100%) was occurred for size

  1. Energy measurement and fragment identification using digital signals from partially depleted Si detectors

    International Nuclear Information System (INIS)

    Pasquali, G.; Pastore, G.; Barlini, S.; Bini, M.; Poggi, G.; Stefanini, A.A.; Valdre, S.; Le Neindre, N.; Bougault, R.; Lopez, O.; Vient, E.; Ademard, G.; Borderie, B.; Edelbruck, P.; Rivet, M.F.; Salomon, F.; Bonnet, E.; Chbihi, A.; Frankland, J.D.; Gruyer, D.; Casini, G.; Olmi, A.; Piantelli, S.; Cinausero, M.; Gramegna, F.; Marchi, T.; Duenas, J.A.; Kordyasz, A.; Kozik, T.; Twarog, T.; Morelli, L.; Ordine, A.; Parlog, M.; Rosato, E.; Spadaccini, G.; Alba, R.; Maiolino, C.; Santonocito, D.

    2014-01-01

    A study of identification properties of a Si-Si ΔE-E telescope exploiting an underdepleted residual-energy detector has been performed. Five different bias voltages have been used, one corresponding to full depletion, the others associated with a depleted layer ranging from 90% to 60% of the detector thickness. Fragment identification has been performed using either the ΔE-E technique or the Pulse Shape Analysis (PSA). Both detectors are reverse mounted: particles enter from the low field side, to enhance the PSA performance. The achieved charge and mass resolution has been quantitatively expressed using a Figure of Merit (FoM). Charge collection efficiency has been evaluated and the possibility of energy calibration corrections has been considered. We find that the ΔE-E performance is not affected by incomplete depletion even when only 60% of the wafer is depleted. Isotopic separation capability improves at lower bias voltages with respect to full depletion, though charge identification thresholds are higher than at full depletion. Good isotopic identification via PSA has been obtained from a partially depleted detector, whose doping uniformity is not good enough for isotopic identification at full depletion. (orig.)

  2. Energy measurement and fragment identification using digital signals from partially depleted Si detectors

    Energy Technology Data Exchange (ETDEWEB)

    Pasquali, G.; Pastore, G.; Barlini, S.; Bini, M.; Poggi, G.; Stefanini, A.A.; Valdre, S. [Universita di Firenze, Dipartimento di Fisica, Sesto Fiorentino (Italy); INFN, Sezione di Firenze, Sesto Fiorentino (Italy); Le Neindre, N.; Bougault, R.; Lopez, O.; Vient, E. [ENSICAEN et Universite de Caen, LPC, IN2P3-CNRS, Caen-Cedex (France); Ademard, G.; Borderie, B.; Edelbruck, P.; Rivet, M.F.; Salomon, F. [Universite Paris-Sud 11, Institut de Physique Nucleaire, CNRS/IN2P3, Orsay cedex (France); Bonnet, E.; Chbihi, A.; Frankland, J.D.; Gruyer, D. [CEA/DSM-CNRS/IN2P3, GANIL, B.P. 5027, Caen cedex (France); Casini, G.; Olmi, A.; Piantelli, S. [INFN, Sezione di Firenze, Sesto Fiorentino (Italy); Cinausero, M.; Gramegna, F.; Marchi, T. [INFN-LNL Legnaro, Legnaro (Padova) (Italy); Duenas, J.A. [FCCEE Universidad de Huelva, Departamento de Fisica Aplicada, Huelva (Spain); Kordyasz, A. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); Kozik, T.; Twarog, T. [Institute of Nuclear Physics IFJ-PAN, Jagiellonian University, Krakow (Poland); Morelli, L. [INFN, Bologna (Italy); Universita di Bologna, Bologna (Italy); Ordine, A. [INFN, Sezione di Napoli, Napoli (Italy); Parlog, M. [ENSICAEN et Universite de Caen, LPC, IN2P3-CNRS, Caen-Cedex (France); ' ' Horia Hulubei' ' National Institute of Physics and Nuclear Engineering, Bucharest (Romania); Rosato, E.; Spadaccini, G. [INFN, Sezione di Napoli, Napoli (Italy); Universita di Napoli ' ' Federico II' ' , Dipartimento di Fisica, Napoli (Italy); Alba, R.; Maiolino, C.; Santonocito, D. [INFN-LNS Catania, Catania (Italy); Collaboration: FAZIA Collaboration

    2014-05-15

    A study of identification properties of a Si-Si ΔE-E telescope exploiting an underdepleted residual-energy detector has been performed. Five different bias voltages have been used, one corresponding to full depletion, the others associated with a depleted layer ranging from 90% to 60% of the detector thickness. Fragment identification has been performed using either the ΔE-E technique or the Pulse Shape Analysis (PSA). Both detectors are reverse mounted: particles enter from the low field side, to enhance the PSA performance. The achieved charge and mass resolution has been quantitatively expressed using a Figure of Merit (FoM). Charge collection efficiency has been evaluated and the possibility of energy calibration corrections has been considered. We find that the ΔE-E performance is not affected by incomplete depletion even when only 60% of the wafer is depleted. Isotopic separation capability improves at lower bias voltages with respect to full depletion, though charge identification thresholds are higher than at full depletion. Good isotopic identification via PSA has been obtained from a partially depleted detector, whose doping uniformity is not good enough for isotopic identification at full depletion. (orig.)

  3. Digitization

    DEFF Research Database (Denmark)

    Finnemann, Niels Ole

    2014-01-01

    what a concept of digital media might add to the understanding of processes of mediatization and what the concept of mediatization might add to the understanding of digital media. It is argued that digital media open an array of new trajectories in human communication, trajectories which were...

  4. Radiographic testing of wood

    International Nuclear Information System (INIS)

    Osterloh, K.; Zscherpel, U.; Raedel, C.; Weidemann, G.; Meinel, D.; Goebbels, J.; Ewert, U.; Hasenstab, A.; Buecherl, T.

    2007-01-01

    Wood is an old and established consumption and construction material. It is still the most common material for constructing furniture, roofs, playgrounds and mine supports. In contrast to steel and concrete, wood warns of extreme loads by creaking. Its mechanical stability is more influenced by decay than by peripheral cracks. While external cracks are visible, internal decay by fungus growth is undetectable from outside. This may be a safety problem in supporting structures. The best analysis of the internal structure is provided by computed tomography, but this is also the most complex method, much more so than simple radiographic testing. However, the latter is made inaccurate by scattered radiation resulting from internal moisture. With the image processing options of digital radiographic techniques, the structural information can be separated effectively from noise. In contrast to X-ray and gamma radiography, neutron radiography provides information on the spatial distribution of moisture. In healthy wood, water is conducted in the sapwood while the hardwood is dry. Moisture in hardwood is caused by infestations, e.g. fungus growth. The contribution presents a comparative analysis of the available radiographic methods. (orig.)

  5. Radiographic element

    International Nuclear Information System (INIS)

    Abbott, T.I.; Jones, C.G.

    1984-01-01

    Radiographic elements are disclosed comprised of first and second silver halide emulsion layers separated by an interposed support capable of transmitting radiation to which the second image portion is responsive. At least the first imaging portion contains a silver halide emulsion in which thin tubular silver halide grains of intermediate aspect ratios (from 5:1 to 8:1) are present. Spectral sensitizing dye is adsorbed to the surface of the tubular grains. Increased photographic speeds can be realized at comparable levels of crossover. (author)

  6. A 75 ps rms time resolution BiCMOS time to digital converter optimized for high rate imaging detectors

    CERN Document Server

    Hervé, C

    2002-01-01

    This paper presents an integrated time to digital converter (TDC) with a bin size adjustable in the range of 125 to 175 ps and a differential nonlinearity of +-0.3%. The TDC has four channels. Its architecture has been optimized for the readout of imaging detectors in use at Synchrotron Radiation facilities. In particular, a built-in logic flags piled-up events. Multi-hit patterns are also supported for other applications. Time measurements are extracted off chip at the maximum throughput of 40 MHz. The dynamic range is 14 bits. It has been fabricated in 0.8 mu m BiCMOS technology. Time critical inputs are PECL compatible whereas other signals are CMOS compatible. A second application specific integrated circuit (ASIC) has been developed which translates NIM electrical levels to PECL ones. Both circuits are used to assemble board level TDCs complying with industry standards like VME, NIM and PCI.

  7. The design and imaging characteristics of dynamic, solid-state, flat-panel x-ray image detectors for digital fluoroscopy and fluorography

    International Nuclear Information System (INIS)

    Cowen, A.R.; Davies, A.G.; Sivananthan, M.U.

    2008-01-01

    Dynamic, flat-panel, solid-state, x-ray image detectors for use in digital fluoroscopy and fluorography emerged at the turn of the millennium. This new generation of dynamic detectors utilize a thin layer of x-ray absorptive material superimposed upon an electronic active matrix array fabricated in a film of hydrogenated amorphous silicon (a-Si:H). Dynamic solid-state detectors come in two basic designs, the indirect-conversion (x-ray scintillator based) and the direct-conversion (x-ray photoconductor based). This review explains the underlying principles and enabling technologies associated with these detector designs, and evaluates their physical imaging characteristics, comparing their performance against the long established x-ray image intensifier television (TV) system. Solid-state detectors afford a number of physical imaging benefits compared with the latter. These include zero geometrical distortion and vignetting, immunity from blooming at exposure highlights and negligible contrast loss (due to internal scatter). They also exhibit a wider dynamic range and maintain higher spatial resolution when imaging over larger fields of view. The detective quantum efficiency of indirect-conversion, dynamic, solid-state detectors is superior to that of both x-ray image intensifier TV systems and direct-conversion detectors. Dynamic solid-state detectors are playing a burgeoning role in fluoroscopy-guided diagnosis and intervention, leading to the displacement of x-ray image intensifier TV-based systems. Future trends in dynamic, solid-state, digital fluoroscopy detectors are also briefly considered. These include the growth in associated three-dimensional (3D) visualization techniques and potential improvements in dynamic detector design

  8. Improvement of the GERDA Ge Detectors Energy Resolution by an Optimized Digital Signal Processing

    Science.gov (United States)

    Benato, G.; D'Andrea, V.; Cattadori, C.; Riboldi, S.

    GERDA is a new generation experiment searching for neutrinoless double beta decay of 76Ge, operating at INFN Gran Sasso Laboratories (LNGS) since 2010. Coaxial and Broad Energy Germanium (BEGe) Detectors have been operated in liquid argon (LAr) in GERDA Phase I. In the framework of the second GERDA experimental phase, both the contacting technique, the connection to and the location of the front end readout devices are novel compared to those previously adopted, and several tests have been performed. In this work, starting from considerations on the energy scale stability of the GERDA Phase I calibrations and physics data sets, an optimized pulse filtering method has been developed and applied to the Phase II pilot tests data sets, and to few GERDA Phase I data sets. In this contribution the detector performances in term of energy resolution and time stability are here presented. The improvement of the energy resolution, compared to standard Gaussian shaping adopted for Phase I data analysis, is discussed and related to the optimized noise filtering capability. The result is an energy resolution better than 0.1% at 2.6 MeV for the BEGe detectors operated in the Phase II pilot tests and an improvement of the energy resolution in LAr of about 8% achieved on the GERDA Phase I calibration runs, compared to previous analysis algorithms.

  9. Simulation of 3D-treatment plans in head and neck tumors aided by matching of digitally reconstructed radiographs (DRR) and on-line distortion corrected simulator images

    International Nuclear Information System (INIS)

    Lohr, Frank; Schramm, Oliver; Schraube, Peter; Sroka-Perez, Gabriele; Seeber, Steffen; Schlepple, Gerd; Schlegel, Wolfgang; Wannenmacher, Michael

    1997-01-01

    Background and purpose: Simulation of 3D-treatment plans for head and neck malignancy is difficult due to complex anatomy. Therefore, CT-simulation and stereotactic techniques are becoming more common in the treatment preparation, overcoming the need for simulation. However, if simulation is still performed, it is an important step in the treatment preparation/execution chain, since simulation errors, if not detected immediately, can compromise the success of treatment. A recently developed PC-based system for on-line image matching and comparison of digitally reconstructed radiographs (DRR) and distortion corrected simulator monitor images that enables instant correction of field placement errors during the simulation process was evaluated. The range of field placement errors with noncomputer aided simulation is reported. Materials and methods: For 14 patients either a primary 3D-treatment plan or a 3D-boost plan after initial treatment with opposing laterals for head and neck malignancy with a coplanar or non-coplanar two- or three-field technique was simulated. After determining the robustness of the matching process and the accuracy of field placement error detection with phantom measurements, DRRs were generated from the treatment planning CT-dataset of each patient and were interactively matched with on-line simulator images that had undergone correction for geometrical distortion, using a landmark algorithm. Translational field placement errors in all three planes as well as in-plane rotational errors were studied and were corrected immediately. Results: The interactive matching process is very robust with a tolerance of <2 mm when suitable anatomical landmarks are chosen. The accuracy for detection of translational errors in phantom measurements was <1 mm and for in-plane rotational errors the accuracy had a maximum of only 1.5 deg.. For patient simulation, the mean absolute distance of the planned versus simulated isocenter was 6.4 ± 3.9 mm. The in

  10. 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.

  11. Detector, collimator and real-time reconstructor for a new scanning-beam digital x-ray (SBDX) prototype.

    Science.gov (United States)

    Speidel, Michael A; Tomkowiak, Michael T; Raval, Amish N; Dunkerley, David A P; Slagowski, Jordan M; Kahn, Paul; Ku, Jamie; Funk, Tobias

    Scanning-beam digital x-ray (SBDX) is an inverse geometry fluoroscopy system for low dose cardiac imaging. The use of a narrow scanned x-ray beam in SBDX reduces detected x-ray scatter and improves dose efficiency, however the tight beam collimation also limits the maximum achievable x-ray fluence. To increase the fluence available for imaging, we have constructed a new SBDX prototype with a wider x-ray beam, larger-area detector, and new real-time image reconstructor. Imaging is performed with a scanning source that generates 40,328 narrow overlapping projections from 71 × 71 focal spot positions for every 1/15 s scan period. A high speed 2-mm thick CdTe photon counting detector was constructed with 320×160 elements and 10.6 cm × 5.3 cm area (full readout every 1.28 μs), providing an 86% increase in area over the previous SBDX prototype. A matching multihole collimator was fabricated from layers of tungsten, brass, and lead, and a multi-GPU reconstructor was assembled to reconstruct the stream of captured detector images into full field-of-view images in real time. Thirty-two tomosynthetic planes spaced by 5 mm plus a multiplane composite image are produced for each scan frame. Noise equivalent quanta on the new SBDX prototype measured 63%-71% higher than the previous prototype. X-ray scatter fraction was 3.9-7.8% when imaging 23.3-32.6 cm acrylic phantoms, versus 2.3-4.2% with the previous prototype. Coronary angiographic imaging at 15 frame/s was successfully performed on the new SBDX prototype, with live display of either a multiplane composite or single plane image.

  12. An Efficient Digital Pulse Shape Discrimination Technique for Scintillation Detectors Based on FPGA

    International Nuclear Information System (INIS)

    Kamel, M.S.

    2014-01-01

    Different techniques for pulse discrimination (PSD) of the scintillation pulses have been developed. The PSD of scintillation pulese can been used in several applications as Positron Emission Topography (PET) system. Each technique analyzes the resulting pulses from the absorption of radiation in the scintillation pulses were filtered and digitized then it is captured using DAQ, and it sent to the host computer for processing. The spatial resolution of images that generated in PET system can be improved by applying the proposed PSD. In this thesis various digital PSD techniques are proposed to discriminate the scintillation pulses. These techniques are based on discrete sine transform (DST). discrete cosine transform (DCT). Discrete hartley transform (DHT), Discrete Goertzel transform (DGT),and principal component analysis (PCA). Then the output coefficients of the discrete transforms are classified using one of the following classifiers T-test,tuned, or support vector machine (SVM).

  13. 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.

  14. Progress on the development of a detector mounted analog and digital readout system for the ATLAS TRT

    CERN Document Server

    Baxter, C; Dressnandt, N; Gay, C; Lundberg, B; Munar, A; Mayers, G; Newcomer, M; Van Berg, R; Williams, H H

    2004-01-01

    The 430,000 element ATLAS Transition Radiation straw tube Tracker (TRT) is divided into a central barrel tracker consisting of 104,000 axially mounted straws and two radially arranged end caps on either side of the barrel with 160,000 straws each. To achieve a track position resolution of 140 mu m, the front end electronics must operate at a low (2fC) threshold with a time marking capability of ~1ns. Two ASICs, the ASDBLR and DTMROC provide the complete pipelined readout chain. Custom designed FBGA packages for the ASICs provide a small enough outline to be detector mounted and the extensive use of low level differential signals make mounting the analog packages on printed circuit boards directly opposite the 40 MHz digital chips feasible. The readout electronics for the barrel occupies a potentially important part of the active tracker volume and an aggressive effort has been made to make it as compact as possible. Utilizing a single board for both analog and digital ASICS a 0.1 cm /sup 3/ per channel volume...

  15. Clinical evaluation of digital angiographic system equipped with the Safire' flat-panel detector of a direct conversion type

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Yoshiaki; Miura, Yusuke; Goto, Keiichi [Shimadzu Corporation, Medical Systems Division, Research and Development, Kyoto (JP)] [and others

    2003-06-01

    This report presents a report on clinical evaluation of our newly developed flat-panel X-ray detector of a direct conversion type, designed to provide images of a resolution higher than, or at least equal to, that ensured by X-ray photographic films, in clinical digital X-ray cinematography. This new detector was named 'Safire' the acronym of 'Shimadzu advanced flat imaging receptor', emphasizing its high technological level, such as the capability to ensure high quality of images. The clinical evaluation of Shimadzu DIGITEX Premier digital angiography system, equipped with this new flat-panel X-ray detector of a direct conversion type, has been started in March, 2003, at the Kokura Memorial Hospital in Kyushu, Japan. (author)

  16. Description of the EDF research and development laboratory's radiographic picture processing system

    International Nuclear Information System (INIS)

    Brillault, B.

    1985-01-01

    A digital radiographic picture processing system has been developed at the EDF Research and Development Laboratory to be supplied to EDF radiography experts. We describe it in pointing out the difficulties of radiograph digitization but also the numerous processing possibilities. The final goal of the Laboratory work is to extract the information from industrial radiographs by digital means. Our study is divided into three parts: digitization by a microdensitometer; display, processing and quantization of flaws; and, digital storing. 5 refs

  17. A Novel Front-End ASIC With Post Digital Filtering and Calibration for CZT-Based PET Detector

    International Nuclear Information System (INIS)

    Gao, W.; Yin, J.; Li, C.; Zeng, H.; Gao, D.; Hu, Y.

    2015-01-01

    This paper presents a novel front-end electronics based on a front-end ASIC with post digital filtering and calibration dedicated to CZT detectors for PET imaging. A cascade amplifier based on split-leg topology is selected to realize the charge-sensitive amplifier (CSA) for the sake of low noise performances and the simple scheme of the power supplies. The output of the CSA is connected to a variable-gain amplifier to generate the compatible signals for the A/D conversion. A multi-channel single-slope ADC is designed to sample multiple points for the digital filtering and shaping. The digital signal processing algorithms are implemented by a FPGA. To verify the proposed scheme, a front-end readout prototype ASIC is designed and implemented in 0.35 μm CMOS process. In a single readout channel, a CSA, a VGA, a 10-bit ADC and registers are integrated. Two dummy channels, bias circuits, and time controller are also integrated. The die size is 2.0 mm x 2.1 mm. The input range of the ASIC is from 2000 e - to 100000 e - , which is suitable for the detection of the X-and gamma ray from 11.2 keV to 550 keV. The linearity of the output voltage is less than 1 %. The gain of the readout channel is 40.2 V/pC. The static power dissipation is about 10 mW/channel. The above tested results show that the electrical performances of the ASIC can well satisfy PET imaging applications. (authors)

  18. A Novel Front-End ASIC With Post Digital Filtering and Calibration for CZT-Based PET Detector

    Energy Technology Data Exchange (ETDEWEB)

    Gao, W.; Yin, J.; Li, C.; Zeng, H.; Gao, D. [Institute of Microelectronics, School of Computer Science and Techonology, Northwestern Polytechnical University, Xi' an (China); Hu, Y. [Institut Pluridiscipline Hubert Curien, CNRS/UDS/IN2P3, Strasbourg (France)

    2015-07-01

    This paper presents a novel front-end electronics based on a front-end ASIC with post digital filtering and calibration dedicated to CZT detectors for PET imaging. A cascade amplifier based on split-leg topology is selected to realize the charge-sensitive amplifier (CSA) for the sake of low noise performances and the simple scheme of the power supplies. The output of the CSA is connected to a variable-gain amplifier to generate the compatible signals for the A/D conversion. A multi-channel single-slope ADC is designed to sample multiple points for the digital filtering and shaping. The digital signal processing algorithms are implemented by a FPGA. To verify the proposed scheme, a front-end readout prototype ASIC is designed and implemented in 0.35 μm CMOS process. In a single readout channel, a CSA, a VGA, a 10-bit ADC and registers are integrated. Two dummy channels, bias circuits, and time controller are also integrated. The die size is 2.0 mm x 2.1 mm. The input range of the ASIC is from 2000 e{sup -} to 100000 e{sup -}, which is suitable for the detection of the X-and gamma ray from 11.2 keV to 550 keV. The linearity of the output voltage is less than 1 %. The gain of the readout channel is 40.2 V/pC. The static power dissipation is about 10 mW/channel. The above tested results show that the electrical performances of the ASIC can well satisfy PET imaging applications. (authors)

  19. A new digital method for high precision neutron-gamma discrimination with liquid scintillation detectors

    International Nuclear Information System (INIS)

    Nakhostin, M

    2013-01-01

    A new pulse-shape discrimination algorithm for neutron and gamma (n/γ) discrimination with liquid scintillation detectors has been developed, leading to a considerable improvement of n/γ separation quality. The method is based on triangular pulse shaping which offers a high sensitivity to the shape of input pulses, as well as, excellent noise filtering characteristics. A clear separation of neutrons and γ-rays down to a scintillation light yield of about 65 keVee (electron equivalent energy) with a dynamic range of 45:1 was achieved. The method can potentially operate at high counting rates and is well suited for real-time measurements.

  20. Radiographic apparatus

    International Nuclear Information System (INIS)

    Lapidus, S.N.

    1979-01-01

    Raytheon Company, U.S.A. have patented an on-line electronic system of normalising the responses from the photomultiplier tubes used in conjunction with a scintillator in an X-ray radiographic camera. A problem with present cameras is that the individual photomultipliers have different intensity responses which also change in time with respect to each other. The individual responses of each photomultiplier tube are measured with a uniform sheet of radioactive material in front of the camera. The associated electronic equipment then calculates scaling factors which give all photomultiplier tubes an identical response and then places these factors in an addressable store. The store is then addressed in an on-line mode to produce a visual display of the transmitted X-rays. (U.K.)

  1. Radiographic apparatus

    International Nuclear Information System (INIS)

    Dalton, B.L.

    1984-01-01

    This patent application describes a radiographic apparatus including an array of radiation sensors, a source of radiation for projecting a beam through a body and means for moving one of said source and array relative to the body and for producing an electrical signal representative of the movement of the other of said source and array needed to bring the array into register with the beam. Drive means are arranged to move the other of said source and array in response to the electrical signal. In one embodiment, the source is rotated by an amount measured by a grating and associated electronics. The required movement of the array to maintain registration is calculated and transmitted to a driver. Alternatively, a laser may be mounted with the same and the array driven so that the laser beam continuously impinges on a photocell mounted with the array. (author)

  2. Development of the digital read-out system for the CERN Alice pixel detector

    CERN Document Server

    Grassi, Tullio

    In order to gain new experimental insight at the TeV energy scale, CERN (Geneva) will build the Large Hadron Collider (LHC), a new collider machine operating at a maximum center-of-mass energy of 14 TeV (in the p+/p+ interactions). The accelerator can operate in a heavy ion collision mode achieving a center-of-mass energy of ~5.5 TeV. The experimental environment at LHC is characterized by a high crossing rate of the particle bunches (one every 25 ns for p+/p+) and high levels of radiation. Therefore stringent requirements are imposed on the performance of detectors at LHC. Such a particle physics environment calls for dedicated hardware/software solutions with specific constraints, such as radiation tolerance, limited amount of material and limited power dissipation. One of the particle physics experiments carried out in LHC is ALICE (A Large Ion Collider Experiment). The ALICE detector will face a very high density of tracks of particles (a multiplicity of 8000 charged particles per unit of rapidity, that i...

  3. 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

  4. Avaliação de métodos indiretos de digitalização de radiografias cefalométricas em comparação ao método digital direto Evaluation of indirect methods of digitization of cephalometric radiographs in comparison with the direct digital method

    Directory of Open Access Journals (Sweden)

    Cleomar Donizeth Rodrigues

    2010-08-01

    Full Text Available OBJETIVO: avaliar métodos de digitalização indireta de radiografias cefalométricas em comparação ao método digital direto. MÉTODOS: a amostra foi composta de dez radiografias cefalométricas adquiridas pelo Orthopantomograph OP100/Orthocef OC100 (GE - Instrumentarium, digital direto. As imagens foram inseridas no programa Adobe Photoshop® e cinco pontos cefalométricos foram marcados. Procedeu-se a impressão em transparência e foi feita a digitalização indireta das imagens impressas, por meio das câmeras fotográficas digitais Sony® DSC-W5 e Canon® Rebel XT/EOS 350D, fixas em estativa, nas distâncias de 25cm e 60cm e com o scanner Scan Jet 4C Hewlett Packard®. As imagens diretas e indiretas foram inseridas e calibradas no software Radiocef Studio (Radiomemory®, Brasil, marcando-se o centro dos pontos previamente assinalados. A análise cefalométrica computadorizada gerou três grandezas angulares e quatro lineares, as quais foram submetidas a tratamento estatístico. RESULTADOS: as imagens do scanner Scan Jet 4C HP® demonstraram pequenas alterações significativas, porém, sem relevância clínica. Quando da digitalização a 60cm da radiografia, as duas câmeras causaram distorções que foram significativas mas clinicamente aceitáveis; e, a 25cm, causaram as maiores distorções, com importância clínica, na Canon® Rebel XT. CONCLUSÃO: o scanner Scan Jet 4C HP® com leitor de transparências foi o melhor método e as câmeras operando a 60cm mostraram-se adequadas para digitalização de radiografias. As câmeras na distância de 25cm causaram distorções na imagem que alteraram as medidas lineares, podendo a Canon® Rebel XT comprometer o diagnóstico ortodôntico.OBJECTIVE: To evaluate the indirect digitization method of cephalometric radiographs in comparison with the direct digital method. METHODS: The sample was composed of ten cephalometric radiographs acquired by Orthopantomograph OP100/Orthocef OC100 (GE

  5. 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.

  6. Radiographers and trainee radiologists reporting accident radiographs

    DEFF Research Database (Denmark)

    Buskov, L; Abild, A; Christensen, A

    2013-01-01

    To compare the diagnostic accuracy and clinical validity of reporting radiographers with that of trainee radiologists whom they have recently joined in reporting emergency room radiographs at Bispebjerg University Hospital....

  7. Normalized noise power spectrum of full field digital mammography detector system

    International Nuclear Information System (INIS)

    Norriza Mohd Isa; Wan Muhamad Saridan Wan Hassan

    2009-01-01

    Full text: A method to measure noise power spectrum of a full field digital mammography system is presented. The effect of X-ray radiation dose, size and configuration of region of interest on normalized noise power spectrum (NNPS) was investigated. Flat field images were acquired using RQA-M2 beam quality technique (Mo/Mo anode-filter, 28 kV, 2 mm Al) with different clinical radiation doses. The images were cropped at about 4 cm from the edge of the breast wall and then divided into different size of non-overlapping or overlapping segments. NNPS was determined through de trending, 2-D fast Fourier transformation and normalization. Our measurement shows that high radiation dose gave lower NNPS at a specific beam quality. (author)

  8. Agreement between radiographic and photographic trabecular patterns

    International Nuclear Information System (INIS)

    Korstjens, C.M.; Geraets, W.G.M.; Stelt, P.F. van der; Spruijt, R.J.; Mosekilde, L.

    1998-01-01

    Purpose: It has been hypothesized that photographs can facilitate the interpretation of the radiographic characteristics of trabecular bone. The reliability of these photographic and radiographic approaches has been determined, as have various agreements between the two approaches and their correlations with biomechanical characteristics. Material and Methods: Fourteen vertebral bodies were obtained at autopsy from 6 women and 8 men aged 22-76 years. Photographs (n=28) and radiographs (n=28) were taken of midsagittal slices from the third lumbar vertebra. The radiographs and photographs were digitized and the geometric properties of the trabecular architecture were then determined with a digital images analysis technique. Information on the compressive strength and ash density of the vertebral body was also available. Results: The geometric properties of both radiographs and photographs could be measured with a high degree of reliability (Cronbach's α>0.85). Agreement between the radiographic and photographic approaches was mediocre as only the radiographic measurements showed insignificant correlations (p<0.05) with the biomechanical characteristics. We suggest that optical phenomena may result in the significant correlations between the photographs and the biomechanical characteristics. Conclusion: For digital image processing, radiography offers a superior description of the architecture of trabecular bone to that offered by photography. (orig.)

  9. Agreement between radiographic and photographic trabecular patterns

    Energy Technology Data Exchange (ETDEWEB)

    Korstjens, C.M.; Geraets, W.G.M.; Stelt, P.F. van der [Dept. of Oral Radiology, Academic Centre for Dentistry, Amsterdam (Netherlands); Spruijt, R.J. [Div. of Psychosocial Research and Epidemiology, Netherlands Cancer Inst., Amsterdam (Netherlands); Mosekilde, L. [Dept. of Cell Biology, Univ. of Aarhus (Denmark)

    1998-11-01

    Purpose: It has been hypothesized that photographs can facilitate the interpretation of the radiographic characteristics of trabecular bone. The reliability of these photographic and radiographic approaches has been determined, as have various agreements between the two approaches and their correlations with biomechanical characteristics. Material and Methods: Fourteen vertebral bodies were obtained at autopsy from 6 women and 8 men aged 22-76 years. Photographs (n=28) and radiographs (n=28) were taken of midsagittal slices from the third lumbar vertebra. The radiographs and photographs were digitized and the geometric properties of the trabecular architecture were then determined with a digital images analysis technique. Information on the compressive strength and ash density of the vertebral body was also available. Results: The geometric properties of both radiographs and photographs could be measured with a high degree of reliability (Cronbach`s {alpha}>0.85). Agreement between the radiographic and photographic approaches was mediocre as only the radiographic measurements showed insignificant correlations (p<0.05) with the biomechanical characteristics. We suggest that optical phenomena may result in the significant correlations between the photographs and the biomechanical characteristics. Conclusion: For digital image processing, radiography offers a superior description of the architecture of trabecular bone to that offered by photography. (orig.)

  10. Energy resolution and throughput of a new real time digital pulse processing system for x-ray and gamma ray semiconductor detectors

    International Nuclear Information System (INIS)

    Abbene, L; Gerardi, G; Raso, G; Brai, M; Principato, F; Basile, S

    2013-01-01

    New generation spectroscopy systems have advanced towards digital pulse processing (DPP) approaches. DPP systems, based on direct digitizing and processing of detector signals, have recently been favoured over analog pulse processing electronics, ensuring higher flexibility, stability, lower dead time, higher throughput and better spectroscopic performance. In this work, we present the performance of a new real time DPP system for X-ray and gamma ray semiconductor detectors. The system is based on a commercial digitizer equipped with a custom DPP firmware, developed by our group, for on-line pulse shape and height analysis. X-ray and gamma ray spectra measurements with cadmium telluride (CdTe) and germanium (Ge) detectors, coupled to resistive-feedback preamplifiers, highlight the excellent performance of the system both at low and high rate environments (up to 800 kcps). A comparison with a conventional analog electronics showed the better high-rate capabilities of the digital approach, in terms of energy resolution and throughput. These results make the proposed DPP system a very attractive tool for both laboratory research and for the development of advanced detection systems for high-rate-resolution spectroscopic imaging, recently proposed in diagnostic medicine, industrial imaging and security screening

  11. A 5-year prospective radiographic evaluation of marginal bone levels adjacent to parallel-screw cylinder machined-neck implants and rough-surfaced microthreaded implants using digitized panoramic radiographs.

    Science.gov (United States)

    Nickenig, Hans-Joachim; Wichmann, Manfred; Happe, Arndt; Zöller, Joachim E; Eitner, Stephan

    2013-10-01

    The purpose of this split-mouth study was to compare macro- and microstructure implant surfaces at the marginal bone level over five years of functional loading. From January to February 2006, 133 implants (70 rough-surfaced microthreaded implants and 63 machined-neck implants) were inserted in the mandible of 34 patients with Kennedy Class I residual dentitions and followed until December 2011. Marginal bone level was radiographically determined at six time points: implant placement (baseline), after the healing period, after six months, and at two years, three years, and five years follow-up. Median follow-up time was 5.2 years (range: 5.1-5.4). The machined-neck group had a mean crestal bone loss of 0.5 mm (0.0-2.3) after the healing period, 1.1 mm (0.0-3.0) at two years follow-up, and 1.4 mm (0.0-2.9) at five years follow-up. The rough-surfaced microthreaded implant group had a mean bone loss of 0.1 mm (-0.4 to 2.0) after the healing period, 0.5 mm (0.0-2.1) at two years follow-up, and 0.7 mm (0.0-2.3) at five years follow-up. The two implant types showed significant differences in marginal bone levels. Rough-surfaced microthreaded design caused significantly less loss of crestal bone levels under long-term functional loading in the mandible when compared to machined-neck implants. Copyright © 2012 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  12. 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.)

  13. Radiographic tales

    DEFF Research Database (Denmark)

    Mussmann, Bo Redder

    Purpose Until now a large number of scientific studies have focused on technological aspects of radiography. This study is a step in another direction which examines the relationship between man and technology within radiography instead of considering man and technology as separate entities. Meth...... of their narrative alertness. Errors and failure to keep the time schedule can, however, lead the radiographers to a change of perspective that makes them displace man from the scene of radiography by playing on the premises of technology.......Purpose Until now a large number of scientific studies have focused on technological aspects of radiography. This study is a step in another direction which examines the relationship between man and technology within radiography instead of considering man and technology as separate entities...... a practice in which the relationship between man and technology is marked by a struggle of domination of one over the other. The struggle expresses itself through two competing plots: A diagnostic plot with a prevailing, but not merely chronological structure mostly composed of events tied to pathology...

  14. A radiographic examination system

    International Nuclear Information System (INIS)

    Cable, A.P.; Cable, W.S.

    1983-01-01

    A system for performing radiographic examination, particularly of large items such as international container units is disclosed. The system is formed as an installation comprising housings for respective linear accelerators transmitting a beam of radiation across the path of a conveyor along which the units can be displaced continuously or incrementally. On either end of the installation are container handling areas including roller conveyors with drag chains and transverse manipulators, and the whole installation is secured within automatically operated doors which seal the high energy region when a container on the conveyor is being subjected to examination. The radiation transmitted through a container is detected in a detector system incorporating a fluoroscopic screen light output from which is detected in a camera system such as a television camera, and transmitted as coded pulsed signals by a coding transfer unit to display screens where an image of the transmitted information can be displayed and/or recorded for further use. (author)

  15. DIGITAL

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — The Digital Flood Insurance Rate Map (DFIRM) Database depicts flood risk information and supporting data used to develop the risk data. The primary risk...

  16. 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

  17. Gd2O3:Eu3+/PPO/POPOP/PS composites for digital imaging radiation detectors

    International Nuclear Information System (INIS)

    Oliveira, J.; Correia, V.; Martins, P.M.; Martins, P.; Lanceros-Mendez, S.; Rocha, J.G.

    2015-01-01

    Polymer-based scintillator composites have been produced by combining polystyrene (PS) and Gd 2 O 3 :Eu 3+ scintillator nanoparticles. Polystyrene has been used since it is a flexible and stable binder matrix, resistant to thermal and light deterioration and with suitable optical properties. Gd 2 O 3 :Eu 3+ has been selected as scintillator material due to its wide band gap, high density and visible light yield. The optical, thermal and electrical characteristics of the composites were studied as a function of filler content, together with their performance as scintillator material. Additionally 1 wt.% of 2,5-diphenyloxazole (PPO) and 0.01 wt.% of 1,4 di[2-(5phenyloxazolyl)]benzene (POPOP) were introduced in the polymer matrix in order to strongly improve light yield, i.e., the measured intensity of the output visible radiation, under X-ray irradiation. Increasing scintillator filler concentration (from 0.25 to 7.5 wt.%) increases scintillator light yield and decreases the optical transparency of the composite. The addition of PPO and POPOP strongly increased the overall transduction performance of the composite due to specific absorption and re-emission processes. It is thus shown that Gd 2 O 3 :Eu 3+ /PPO/POPOP/PS composites with 0.25 wt.% of scintillator content with fluorescence molecules are suitable for the development of innovative large-area X-ray radiation detectors with huge demand from the industries. (orig.)

  18. Performance evaluation of a retrofit digital detector-based mammography system.

    Science.gov (United States)

    Marshall, Nicholas W; van Ongeval, Chantal; Bosmans, Hilde

    2016-02-01

    A retrofit flat panel detector was integrated with a GE DMR+ analog mammography system and characterized using detective quantum efficiency (DQE). Technical system performance was evaluated using the European Guidelines protocol, followed by a limited evaluation of clinical image quality for 20 cases using image quality criteria in the European Guidelines. Optimal anode/filter selections were established using signal difference-to-noise ratio measurements. Only small differences in peak DQE were seen between the three anode/filter settings, with an average value of 0.53. For poly(methyl methacrylate) (PMMA) thicknesses above 60 mm, the Rh/Rh setting was the optimal anode/filter setting. The system required a mean glandular dose of 0.54 mGy at 30 kV Rh/Rh to reach the Acceptable gold thickness limit for 0.1 mm details. Imaging performance of the retrofit unit with the GE DMR+ is notably better than of powder based computed radiography systems and is comparable to current flat panel FFDM systems. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  19. Chronic thromboembolic pulmonary hypertension: Evaluation with 64-detector row CT versus digital substraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Reichelt, Angela [Department of Diagnostic Radiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover (Germany)], E-mail: Reichelt.Angela@mh-hannover.de; Hoeper, Marius M. [Department of Respiratory Medicine, Hannover Medical School (Germany); Galanski, Michael [Department of Diagnostic Radiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover (Germany); Keberle, Marc [Department of Diagnostic Radiology and Nuclear Medicine, Bruederkrankenhaus St. Josef Paderborn (Germany)

    2009-07-15

    The aim of the study was to evaluate the role of 64-row CT in the diagnostic workup of patients with chronic thromboembolic pulmonary hypertension (CTEPH) using digital substraction angiography (DSA) as the method of diagnostic reference. CT and DSA studies of 27 patients (54 main, 162 lobar and 540 segmental arteries) with a clinical suspicion of CTEPH were included in this retrospective and blinded analysis. Axial images and multiplanar thin maximum intensity projections (MIPs) (3 mm) were consequently used for exact image interpretation whereas additional reconstructed thick MIPs gave an overview of the entire vascular tree comparable to DSA. Sensitivity and specificity of CT regarding CTEPH-related pathological changes in general were 98.3% and 94.8% at main/lobar level and 94.1% and 92.9% at segmental level, respectively. Sensitivity and specificity of CT regarding the different pathological criteria of CTEPH (complete obstruction, intimal irregularities, bands and webs, indirect signs) were 88.9-100% and 96.1-100% at main/lobar level and 84.3-90.5% and 92-98.7% at segmental level, respectively. Our results show that CT is an accurate and reliable non-invasive alternative to conventional DSA in the diagnostic workup in patients with CTEPH.

  20. Chronic thromboembolic pulmonary hypertension: Evaluation with 64-detector row CT versus digital substraction angiography

    International Nuclear Information System (INIS)

    Reichelt, Angela; Hoeper, Marius M.; Galanski, Michael; Keberle, Marc

    2009-01-01

    The aim of the study was to evaluate the role of 64-row CT in the diagnostic workup of patients with chronic thromboembolic pulmonary hypertension (CTEPH) using digital substraction angiography (DSA) as the method of diagnostic reference. CT and DSA studies of 27 patients (54 main, 162 lobar and 540 segmental arteries) with a clinical suspicion of CTEPH were included in this retrospective and blinded analysis. Axial images and multiplanar thin maximum intensity projections (MIPs) (3 mm) were consequently used for exact image interpretation whereas additional reconstructed thick MIPs gave an overview of the entire vascular tree comparable to DSA. Sensitivity and specificity of CT regarding CTEPH-related pathological changes in general were 98.3% and 94.8% at main/lobar level and 94.1% and 92.9% at segmental level, respectively. Sensitivity and specificity of CT regarding the different pathological criteria of CTEPH (complete obstruction, intimal irregularities, bands and webs, indirect signs) were 88.9-100% and 96.1-100% at main/lobar level and 84.3-90.5% and 92-98.7% at segmental level, respectively. Our results show that CT is an accurate and reliable non-invasive alternative to conventional DSA in the diagnostic workup in patients with CTEPH.

  1. 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

  2. Calibration of gamma-ray detectors using Gaussian photopeak fitting in the multichannel spectra with a LabVIEW-based digital system

    Science.gov (United States)

    Schlattauer, Leo; Parali, Levent; Pechousek, Jiri; Sabikoglu, Israfil; Celiktas, Cuneyt; Tektas, Gozde; Novak, Petr; Jancar, Ales; Prochazka, Vit

    2017-09-01

    This paper reports on the development of a gamma-ray spectroscopic system for the (i) recording and (ii) processing of spectra. The utilized data read-out unit consists of a PCI digital oscilloscope, personal computer and LabVIEW™ programming environment. A pulse-height spectra of various sources were recorded with two NaI(Tl) detectors and analyzed, demonstrating the proper usage of the detectors. A multichannel analyzer implements the Gaussian photopeak fitting. The presented method provides results which are in compliance to the ones taken from commercial spectroscopy systems. Each individual hardware or software unit can be further utilized in different spectrometric user-systems. An application of the developed system for research and teaching purposes regarding the design of digital spectrometric systems has been successfully tested at the laboratories of the Department of Experimental Physics.

  3. PACS influence the radiographer's work

    International Nuclear Information System (INIS)

    Fridell, Kent; Aspelin, Peter; Edgren, Lars; Lindskoeld, Lars; Lundberg, Nina

    2009-01-01

    Radiological departments are changing rapidly due to the implementation of digital images and PACS (Picture Archiving and Communication Systems). The introduction of new technology seems to dissolve boundaries between the professions in the work environment where the technology is introduced. This process tends to change the organization and its routines. The aim of this qualitative study is to explore changes in radiographers' work with regard to skills, work practice and technology. The study used open-ended interviews to explore the radiographers' perceptions of such changes, and to identify problems and solutions pertaining to work practice. Inspiration is taken from grounded theory to explain the changes in work that were found. Respondents were selected from a total of 133 potential participants as a theoretical or purposive sample. The changing trends within the professional role indicated that radiographers, as image producers, shifted their focus from the ability to set the optimal exposure parameters in order to obtain the optimal image for diagnosis to become expert in exposure parameters, projection techniques and diagnostic practice, having multifaceted skills, as being the jack of all trades. When implementing PACS there was an obvious change in image production. At the start there were visions of new routines, and therefore the radiographers became early adopters to the new technology; in practice the organization was stacked in old routines, as the routines were inflexible and PACS work was pushed into old work routines. Although inflexible, this does not mean that they cannot change, and obviously in 2006 new routines had been implemented making it possible for the radiographers in finding new ways for collaborating with colleagues. The new technology immediately created a vision of improved service to the clinicians. In order to optimize the service the radiographers developed an insight into the need for a more comprehensive change in work using

  4. [Comparison of dignity determination of mammographic microcalcification with two systems for digital full-field mammography with different detector resolution: a retrospective clinical study].

    Science.gov (United States)

    Schulz-Wendtland, R; Hermann, K-P; Adamietz, B; Meier-Meitinger, M; Wenkel, E; Lell, M; Anders, K; Uder, M

    2011-02-01

    The aim of this retrospective clinical study was to compare the diagnostic accuracy of the novel 50 µm FFDM (full-field digital mammography) system (DR) with an established 70 µm system (DR) in the differential diagnosis between benign and malignant clusters of microcalcification (n=50) (BI-RADS™ classification 4/5) and to assess the possible incremental value of the 50 µm pixel-pitch on specificity. From March 2009 to September 2009, 50 patients underwent full-field digital mammography (FFDM) (detector resolution 70 µm) (Novation, Siemens, Erlangen, Germany). As there were suspicious signs of microcalcification classified with BI-RADS™ 4/5 after diagnosis and preoperative wire localization, control images were made with the new FFDM system (detector: resolution 50 µm) (Amulet, Fujifilm, Tokyo, Japan) with the same exposure parameters. The diagnosis was determined after the operation by five radiologists with different experience in digital mammography from randomly distributed mediolateral views (monitor reading) whose results were correlated with the final histology of all lesions. Histopathology revealed 19 benign and 31 malignant lesions in 50 patients after open biopsy. The results of the five readers showed a higher sensitivity of the new FFDM system (80.0%) in the ability to recognize malignant microcalcification in comparison to the established system (74.8%). The specificity (75.8 versus 71.6%) was slightly higher for the new system but these results were not statistically significant (pdetector: resolution 50 µm) was also slightly superior to the well-known system (detector: resolution 70 µm) (80.1% versus 76.4%). Our study has shown that the new full-field digital mammography system using the novel detector compared with the already established FFDM system with respect to the assessment of microcalcification is at least equivalent.

  5. Strategies for dose reduction in ordinary radiographic examinations using CR and DR

    International Nuclear Information System (INIS)

    Willis, C.E.

    2004-01-01

    Uncoupling of display from acquisition in computed radiography (CR) and digital radiography (DR) introduces the potential for systematic overexposure without necessarily compromising image quality. Although the magnitude of radiation doses in general radiography is low compared to computed tomography and fluoroscopy, the dose to the patient is more critical in pediatric examinations than in adults, because of the greater radiosensitivity of children. This manuscript examines a variety of countermeasures for managing radiation doses in pediatric CR and DR examinations, including use of derived exposure indicators, modifications of imaging practice, and development of more efficient radiographic detectors. (orig.)

  6. Radiographic scanner apparatus

    International Nuclear Information System (INIS)

    Wake, R.H.

    1980-01-01

    The preferred embodiment of this invention includes a hardware system, or processing means, which operates faster than software. Moreover the computer needed is less expensive and smaller. Radiographic scanner apparatus is described for measuring the intensity of radiation after passage through a planar region and for reconstructing a representation of the attenuation of radiation by the medium. There is a source which can be rotated, and detectors, the output from which forms a data line. The detectors are disposed opposite the planar region from the source to produce a succession of data lines corresponding to the succession of angular orientations of the source. There is a convolver means for convolving each of these data lines, with a filter function, and a means of processing the convolved data lines to create the representation of the radiation attenuation in the planar region. There is also apparatus to generate a succession of data lines indicating radiation attenuation along a determinable path with convolver means. (U.K.)

  7. Si and gaas pixel detectors for medical imaging applications

    International Nuclear Information System (INIS)

    Bisogni, M. G.

    2001-01-01

    As the use of digital radiographic equipment in the morphological imaging field is becoming the more and more diffuse, the research of new and more performing devices from public institutions and industrial companies is in constant progress. Most of these devices are based on solid-state detectors as X-ray sensors. Semiconductor pixel detectors, originally developed in the high energy physics environment, have been then proposed as digital detector for medical imaging applications. In this paper a digital single photon counting device, based on silicon and GaAs pixel detector, is presented. The detector is a thin slab of semiconductor crystal where an array of 64 by 64 square pixels, 170- m side, has been built on one side. The data read-out is performed by a VLSI integrated circuit named Photon Counting Chip (PCC), developed within the MEDIPIX collaboration. Each chip cell geometrically matches the sensor pixel. It contains a charge preamplifier, a threshold comparator and a 15 bits pseudo-random counter and it is coupled to the detector by means of bump bonding. Most important advantages of such system, with respect to a traditional X-rays film/screen device, are the wider linear dynamic range (3x104) and the higher performance in terms of MTF and DQE. Besides the single photon counting architecture allows to detect image contrasts lower than 3%. Electronics read-out performance as well as imaging capabilities of the digital device will be presented. Images of mammographic phantoms acquired with a standard Mammographic tube will be compared with radiographs obtained with traditional film/screen systems

  8. Method for measuring the focal spot size of an x-ray tube using a coded aperture mask and a digital detector.

    Science.gov (United States)

    Russo, Paolo; Mettivier, Giovanni

    2011-04-01

    The goal of this study is to evaluate a new method based on a coded aperture mask combined with a digital x-ray imaging detector for measurements of the focal spot sizes of diagnostic x-ray tubes. Common techniques for focal spot size measurements employ a pinhole camera, a slit camera, or a star resolution pattern. The coded aperture mask is a radiation collimator consisting of a large number of apertures disposed on a predetermined grid in an array, through which the radiation source is imaged onto a digital x-ray detector. The method of the coded mask camera allows one to obtain a one-shot accurate and direct measurement of the two dimensions of the focal spot (like that for a pinhole camera) but at a low tube loading (like that for a slit camera). A large number of small apertures in the coded mask operate as a "multipinhole" with greater efficiency than a single pinhole, but keeping the resolution of a single pinhole. X-ray images result from the multiplexed output on the detector image plane of such a multiple aperture array, and the image of the source is digitally reconstructed with a deconvolution algorithm. Images of the focal spot of a laboratory x-ray tube (W anode: 35-80 kVp; focal spot size of 0.04 mm) were acquired at different geometrical magnifications with two different types of digital detector (a photon counting hybrid silicon pixel detector with 0.055 mm pitch and a flat panel CMOS digital detector with 0.05 mm pitch) using a high resolution coded mask (type no-two-holes-touching modified uniformly redundant array) with 480 0.07 mm apertures, designed for imaging at energies below 35 keV. Measurements with a slit camera were performed for comparison. A test with a pinhole camera and with the coded mask on a computed radiography mammography unit with 0.3 mm focal spot was also carried out. The full width at half maximum focal spot sizes were obtained from the line profiles of the decoded images, showing a focal spot of 0.120 mm x 0.105 mm at 35

  9. Sub-millimetre DOI detector based on monolithic LYSO and digital SiPM for a dedicated small-animal PET system

    International Nuclear Information System (INIS)

    Marcinkowski, Radosław; Mollet, Pieter; Van Holen, Roel; Vandenberghe, Stefaan

    2016-01-01

    The mouse model is widely used in a vast range of biomedical and preclinical studies. Thanks to the ability to detect and quantify biological processes at the molecular level in vivo, PET has become a well-established tool in these investigations. However, the need to visualize and quantify radiopharmaceuticals in anatomic structures of millimetre or less requires good spatial resolution and sensitivity from small-animal PET imaging systems. In previous work we have presented a proof-of-concept of a dedicated high-resolution small-animal PET scanner based on thin monolithic scintillator crystals and Digital Photon Counter photosensor. The combination of thin monolithic crystals and MLE positioning algorithm resulted in an excellent spatial resolution of 0.7 mm uniform in the entire field of view (FOV). However, the limitation of the scanner was its low sensitivity due to small thickness of the lutetium-yttrium oxyorthosilicate (LYSO) crystals (2 mm). Here we present an improved detector design for a small-animal PET system that simultaneously achieves higher sensitivity and sustains a sub-millimetre spatial resolution. The proposed detector consists of a 5 mm thick monolithic LYSO crystal optically coupled to a Digital Photon Counter. Mean nearest neighbour (MNN) positioning combined with depth of interaction (DOI) decoding was employed to achieve sub-millimetre spatial resolution. To evaluate detector performance the intrinsic spatial resolution, energy resolution and coincidence resolving time (CRT) were measured. The average intrinsic spatial resolution of the detector was 0.60 mm full-width-at-half-maximum (FWHM). A DOI resolution of 1.66 mm was achieved. The energy resolution was 23% FWHM at 511 keV and CRT of 529 ps were measured. The improved detector design overcomes the sensitivity limitation of the previous design by increasing the nominal sensitivity of the detector block and retains an excellent intrinsic spatial resolution. (paper)

  10. Black Lung Benefits Act: standards for chest radiographs. Final rule.

    Science.gov (United States)

    2014-04-17

    Physicians and adjudicators use chest radiographs (X-rays) as a tool in evaluating whether a coal miner suffers from pneumoconiosis (black lung disease). Accordingly, the Department's regulations implementing the Black Lung Benefits Act allow the submission of radiographs in connection with benefit claims and set out quality standards for administering and interpreting film-based chest radiographs. This final rule updates the Department's existing film-radiograph standards and provides parallel standards for digital radiographs. This rule also updates outdated terminology and removes certain obsolete provisions.

  11. Evaluation of peripheral artery stent with 64-slice multi-detector row CT angiography: Prospective comparison with digital subtraction angiography

    International Nuclear Information System (INIS)

    Li Xiaoming; Li Yuhua; Tian Jianming; Xiao Yi; Lu Jianping; Jing Zaiping; Sheng Jing; Edwin, Angela; Wu Fanghong

    2010-01-01

    Purpose: To assess the accuracy of 64-slice multi-detector row computed tomography (MDCT) angiography in the evaluation of peripheral artery in-stent or peristent restenosis, with conventional digital subtraction angiography (DSA) as the reference standard. Materials and methods: Forty-one patients (30 men, 11 women; mean age, 69.8 ± 9.2 years) with symptomatic peripheral arterial occlusive disease after peripheral artery stenting (81 stented lesions) underwent both conventional DSA and 64-slice MDCT angiography. Each stent was classified as evaluable or unevaluable, and every stent was divided into three segments (proximal stent, stent body, and distal stent), resulting in 243 segments. For evaluation, stenosis was graded as follows: 1, none or slight stenosis (<25%); 2, mild stenosis (25-49%); 3, moderate stenosis (50-74%); 4, severe stenosis or total occlusion (≥75%). Two readers evaluated all CT angiograms with regard to narrowing of in-stent or peristent restenosis by consensus. Results were compared with findings of the DSA. Results: Of 81 stents, 62 (76.5%) were determined to be assessable. The metal artifact of the gold marker and motion artifact increased uninterpretability of the images of stents. Overall, 24 of 28 in-stent restenosis and 38 of 53 persistent restenosis were correctly detected by MDCT (85.7% and 71.7% sensitivity). In evaluable stents, 21 of 22 in-stent restenoses and 27 of 28 persistent restenosis were correctly detected (95.4% and 96.4% sensitivity). Additionally, as the grade of stenosis increases, the mean level of CT values in the stent lumina decreases linearly accordingly. Conclusion: 64-Slice MDCT has a high accuracy for the detection of significant in-stent or peristent restenosis of assessable stents in patients with peripheral artery stent implantation and therefore can be considered as a valuable noninvasive technique for stent surveillance.

  12. Automating the radiographic NDT process

    International Nuclear Information System (INIS)

    Aman, J.K.

    1986-01-01

    Automation, the removal of the human element in inspection, has not been generally applied to film radiographic NDT. The justication for automating is not only productivity but also reliability of results. Film remains in the automated system of the future because of its extremely high image content, approximately 8 x 10 9 bits per 14 x 17. The equivalent to 2200 computer floppy discs. Parts handling systems and robotics applied for manufacturing and some NDT modalities, should now be applied to film radiographic NDT systems. Automatic film handling can be achieved with the daylight NDT film handling system. Automatic film processing is becoming the standard in industry and can be coupled to the daylight system. Robots offer the opportunity to automate fully the exposure step. Finally, computer aided interpretation appears on the horizon. A unit which laser scans a 14 x 17 (inch) film in 6 - 8 seconds can digitize film information for further manipulation and possible automatic interrogations (computer aided interpretation). The system called FDRS (for Film Digital Radiography System) is moving toward 50 micron (*approx* 16 lines/mm) resolution. This is believed to meet the need of the majority of image content needs. We expect the automated system to appear first in parts (modules) as certain operations are automated. The future will see it all come together in an automated film radiographic NDT system (author) [pt

  13. Coincidence measurements in α/β/γ spectrometry with phoswich detectors using digital pulse shape discrimination analysis

    Science.gov (United States)

    de Celis, B.; de la Fuente, R.; Williart, A.; de Celis Alonso, B.

    2007-09-01

    A novel system has been developed for the detection of low radioactivity levels using coincidence techniques. The device combines a phoswich detector for α/β/γ ray recognition with a fast digital card for electronic pulse analysis. The detector is able to discriminate different types of radiation in a mixed α/β/γ field and can be used in a coincidence mode by identifying the composite signal produced by the simultaneous detection of β particles in a plastic scintillator and γ rays in an NaI(Tl) scintillator. Use of a coincidence technique with phoswich detectors was proposed recently to verify the Nuclear Test Ban Treaty, which made it necessary to monitor the low levels of xenon radioisotopes produced by underground nuclear explosions. Previous studies have shown that combining CaF 2(Eu) for β ray detection and NaI(Tl) for γ ray detection makes it difficult to identify the coincidence signals because of the similar fluorescence decay times of the two scintillators. With the device proposed here, it is possible to identify the coincidence events owing to the short fluorescence decay time of the plastic scintillator. The sensitivity of the detector may be improved by employing liquid scintillators, which allow low radioactivity levels from actinides to be measured when present in environmental samples. The device developed is simpler to use than conventional coincidence equipment because it uses a single detector and electronic circuit, and it offers fast and precise analysis of the coincidence signals by employing digital pulse shape analysis.

  14. 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.)

  15. Evaluation of the radiopacity of root canal sealers by digitization of radiographic images Avaliação da radiopacidade de cimentos endodônticos por meio da digitalização de imagens radiográficas

    Directory of Open Access Journals (Sweden)

    Juliane Maria Guerreiro Tanomaru

    2004-12-01

    Full Text Available The aim of this study was to evaluate the radiopacity of a zinc oxide and eugenol-based (Endofill, a calcium hydroxide-based (Sealapex, two resin-based (Sealer 26 and AH Plus, and a silicone-based root canal sealer (Roeko Seal. Specimens, measuring 10mm in diameter and 1mm in thickness, were radiographed simultaneously with an aluminum step wedge using occlusal films, according to ISO 6876/2001 standards. Radiographs were digitized, and the radiopacity of sealers was compared to the different thicknesses of the aluminum step wedge, using the VIXWIN 2000 software. Results demonstrated that AH Plus was the most radiopaque sealer, while Sealapex was the least radiopaque (pO objetivo deste trabalho foi avaliar a radiopacidade de cimentos endodônticos à base de óxido de zinco e eugenol (Endofill, hidróxido de cálcio (Sealapex, resina (Sealer 26 e AH Plus e silicone (Roeko Seal. Os corpos de prova foram padronizados com 10 milímetros de diâmetro e 1 milímetro de espessura e radiografados conjuntamente com uma escala de alumínio empregando-se filmes oclusais, de acordo com as Normas ISO 6876/2001. As radiografias foram digitalizadas e as radiopacidades dos cimentos comparadas à escala de alumínio com diferentes espessuras, utilizando o software VIXWIN 2000. Os resultados demonstraram que o AH Plus foi o cimento mais radiopaco e o Sealapex apresentou menor radiopacidade (p<0,05, sendo intermediários os resultados para os cimentos Roeko Seal, Endofill e Sealer 26. Sealapex apresenta menor radiopacidade que outros tipos de cimentos endodônticos.

  16. Radiographic imaging. 4 ed.

    International Nuclear Information System (INIS)

    Chesney, D.N.; Chesney, M.O.

    1981-01-01

    This is a revised edition of the textbook previously entitled 'Radiographic Photography' and accords with the current syllabus of training for the Diploma of the Royal College of Radiographers. The aim is a non-mathematical approach to provide a guide for the student to the knowledge and understanding of the theoretical concepts which affect the quality of radiographic image; materials and practices are also reviewed, particularly in relation to the characteristics of the radiographic image, and to processing equipment and processing areas. The subject is dealt with under the following headings: the photographic process, film materials in x-ray departments, sensitometry, storage of film materials and radiographs, intensifying screens and cassettes, film processing, developing, fixing, rinsing, washing, drying, the processing area and equipment, systems for daylight film handling, the radiographic image, management of the quality, presentation of the radiograph, light images and their recording, fluorography, some special imaging processes, e.g. xerography, copying radiographs. (U.K.)

  17. Adsorbed radioactivity and radiographic imaging of surfaces of stainless steel and titanium

    Science.gov (United States)

    Jung, Haijo

    1997-11-01

    Type 304 stainless steel used for typical surface materials of spent fuel shipping casks and titanium were exposed in the spent fuel storage pool of a typical PWR power plant. Adsorption characteristics, effectiveness of decontamination by water cleaning and by electrocleaning, and swipe effectiveness on the metal surfaces were studied. A variety of environmental conditions had been manipulated to stimulate the potential 'weeping' phenomenon that often occurs with spent fuel shipping casks during transit. In a previous study, few heterogeneous effects of adsorbed contamination onto metal surfaces were observed. Radiographic images of cask surfaces were made in this study and showed clearly heterogeneous activity distributions. Acquired radiographic images were digitized and further analyzed with an image analysis computer package and compared to calibrated images by using standard sources. The measurements of activity distribution by using the radiographic image method were consistent with that using a HPGe detector. This radiographic image method was used to study the effects of electrocleaning for total and specified areas. The Modulation Transfer Function (MTF) of a film-screen system in contact with a radioactive metal surface was studied with neutron activated gold foils and showed more broad resolution properties than general diagnostic x-ray film-screen systems. Microstructure between normal areas and hot spots showed significant differences, and one hot spot appearing as a dot on the film image consisted of several small hot spots (about 10 μm in diameter). These hot spots were observed as structural defects of the metal surfaces.

  18. Stereoscopic radiographic images with thermal neutrons

    International Nuclear Information System (INIS)

    Silvani, M.I.; Almeida, G.L.; Rogers, J.D.; Lopes, R.T.

    2011-01-01

    Spatial structure of an object can be perceived by the stereoscopic vision provided by eyes or by the parallax produced by movement of the object with regard to the observer. For an opaque object, a technique to render it transparent should be used, in order to make visible the spatial distribution of its inner structure, for any of the two approaches used. In this work, a beam of thermal neutrons at the main port of the Argonauta research reactor of the Instituto de Engenharia Nuclear in Rio de Janeiro/Brazil has been used as radiation to render the inspected objects partially transparent. A neutron sensitive Imaging Plate has been employed as a detector and after exposure it has been developed by a reader using a 0.5 μm laser beam, which defines the finest achievable spatial resolution of the acquired digital image. This image, a radiographic attenuation map of the object, does not represent any specific cross-section but a convoluted projection for each specific attitude of the object with regard to the detector. After taking two of these projections at different object attitudes, they are properly processed and the final image is viewed by a red and green eyeglass. For monochromatic images this processing involves transformation of black and white radiographies into red and white and green and white ones, which are afterwards merged to yield a single image. All the processes are carried out with the software ImageJ. Divergence of the neutron beam unfortunately spoils both spatial and contrast resolutions, which become poorer as object-detector distance increases. Therefore, in order to evaluate the range of spatial resolution corresponding to the 3D image being observed, a curve expressing spatial resolution against object-detector gap has been deduced from the Modulation Transfer Functions experimentally. Typical exposure times, under a reactor power of 170 W, were 6 min for both quantitative and qualitative measurements. In spite of its intrinsic constraints

  19. Stereoscopic radiographic images with thermal neutrons

    Science.gov (United States)

    Silvani, M. I.; Almeida, G. L.; Rogers, J. D.; Lopes, R. T.

    2011-10-01

    Spatial structure of an object can be perceived by the stereoscopic vision provided by eyes or by the parallax produced by movement of the object with regard to the observer. For an opaque object, a technique to render it transparent should be used, in order to make visible the spatial distribution of its inner structure, for any of the two approaches used. In this work, a beam of thermal neutrons at the main port of the Argonauta research reactor of the Instituto de Engenharia Nuclear in Rio de Janeiro/Brazil has been used as radiation to render the inspected objects partially transparent. A neutron sensitive Imaging Plate has been employed as a detector and after exposure it has been developed by a reader using a 0.5 μm laser beam, which defines the finest achievable spatial resolution of the acquired digital image. This image, a radiographic attenuation map of the object, does not represent any specific cross-section but a convoluted projection for each specific attitude of the object with regard to the detector. After taking two of these projections at different object attitudes, they are properly processed and the final image is viewed by a red and green eyeglass. For monochromatic images this processing involves transformation of black and white radiographies into red and white and green and white ones, which are afterwards merged to yield a single image. All the processes are carried out with the software ImageJ. Divergence of the neutron beam unfortunately spoils both spatial and contrast resolutions, which become poorer as object-detector distance increases. Therefore, in order to evaluate the range of spatial resolution corresponding to the 3D image being observed, a curve expressing spatial resolution against object-detector gap has been deduced from the Modulation Transfer Functions experimentally. Typical exposure times, under a reactor power of 170 W, were 6 min for both quantitative and qualitative measurements. In spite of its intrinsic constraints

  20. Comparison of dignity determination of mammographic microcalcification with two systems for digital full-field mammography with different detector resolution. A retrospective clinical study

    International Nuclear Information System (INIS)

    Schulz-Wendtland, R.; Adamietz, B.; Meier-Meitinger, M.; Wenkel, E.; Lell, M.; Anders, K.; Uder, M.; Hermann, K.P.

    2011-01-01

    The aim of this retrospective clinical study was to compare the diagnostic accuracy of the novel 50 μm FFDM (full-field digital mammography) system (DR) with an established 70 μm system (DR) in the differential diagnosis between benign and malignant clusters of microcalcification (n=50) (BI-RADS trademark classification 4/5) and to assess the possible incremental value of the 50 μm pixel-pitch on specificity. From March 2009 to September 2009, 50 patients underwent full-field digital mammography (FFDM) (detector resolution 70 μm) (Novation, Siemens, Erlangen, Germany). As there were suspicious signs of microcalcification classified with BI-RADS trademark 4/5 after diagnosis and preoperative wire localization, control images were made with the new FFDM system (detector: resolution 50 μm) (Amulet, Fujifilm, Tokyo, Japan) with the same exposure parameters. The diagnosis was determined after the operation by five radiologists with different experience in digital mammography from randomly distributed mediolateral views (monitor reading) whose results were correlated with the final histology of all lesions. Histopathology revealed 19 benign and 31 malignant lesions in 50 patients after open biopsy. The results of the five readers showed a higher sensitivity of the new FFDM system (80.0%) in the ability to recognize malignant microcalcification in comparison to the established system (74.8%). The specificity (75.8 versus 71.6%) was slightly higher for the new system but hese results were not statistically significant (p [de

  1. 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

  2. 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)

  3. Three-dimensional cascaded system analysis of a 50 µm pixel pitch wafer-scale CMOS active pixel sensor x-ray detector for digital breast tomosynthesis.

    Science.gov (United States)

    Zhao, C; Vassiljev, N; Konstantinidis, A C; Speller, R D; Kanicki, J

    2017-03-07

    High-resolution, low-noise x-ray detectors based on the complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) technology have been developed and proposed for digital breast tomosynthesis (DBT). In this study, we evaluated the three-dimensional (3D) imaging performance of a 50 µm pixel pitch CMOS APS x-ray detector named DynAMITe (Dynamic Range Adjustable for Medical Imaging Technology). The two-dimensional (2D) angle-dependent modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE) were experimentally characterized and modeled using the cascaded system analysis at oblique incident angles up to 30°. The cascaded system model was extended to the 3D spatial frequency space in combination with the filtered back-projection (FBP) reconstruction method to calculate the 3D and in-plane MTF, NNPS and DQE parameters. The results demonstrate that the beam obliquity blurs the 2D MTF and DQE in the high spatial frequency range. However, this effect can be eliminated after FBP image reconstruction. In addition, impacts of the image acquisition geometry and detector parameters were evaluated using the 3D cascaded system analysis for DBT. The result shows that a wider projection angle range (e.g.  ±30°) improves the low spatial frequency (below 5 mm -1 ) performance of the CMOS APS detector. In addition, to maintain a high spatial resolution for DBT, a focal spot size of smaller than 0.3 mm should be used. Theoretical analysis suggests that a pixelated scintillator in combination with the 50 µm pixel pitch CMOS APS detector could further improve the 3D image resolution. Finally, the 3D imaging performance of the CMOS APS and an indirect amorphous silicon (a-Si:H) thin-film transistor (TFT) passive pixel sensor (PPS) detector was simulated and compared.

  4. 50 μm pixel pitch wafer-scale CMOS active pixel sensor x-ray detector for digital breast tomosynthesis.

    Science.gov (United States)

    Zhao, C; Konstantinidis, A C; Zheng, Y; Anaxagoras, T; Speller, R D; Kanicki, J

    2015-12-07

    Wafer-scale CMOS active pixel sensors (APSs) have been developed recently for x-ray imaging applications. The small pixel pitch and low noise are very promising properties for medical imaging applications such as digital breast tomosynthesis (DBT). In this work, we evaluated experimentally and through modeling the imaging properties of a 50 μm pixel pitch CMOS APS x-ray detector named DynAMITe (Dynamic Range Adjustable for Medical Imaging Technology). A modified cascaded system model was developed for CMOS APS x-ray detectors by taking into account the device nonlinear signal and noise properties. The imaging properties such as modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) were extracted from both measurements and the nonlinear cascaded system analysis. The results show that the DynAMITe x-ray detector achieves a high spatial resolution of 10 mm(-1) and a DQE of around 0.5 at spatial frequencies  CMOS APS x-ray detector, image aquisition geometry and image reconstruction techniques should be considered.

  5. Flash radiographic technique applied to fuel injector sprays

    International Nuclear Information System (INIS)

    Vantine, H.C.

    1977-01-01

    A flash radiographic technique, using 50 ns exposure times, was used to study the pattern and density distribution of a fuel injector spray. The experimental apparatus and method are described. An 85 kVp flash x-ray generator, designed and fabricated at the Lawrence Livermore Laboratory, is utilized. Radiographic images, recorded on standard x-ray films, are digitized and computer processed

  6. Radiographic imaging system for high energy radiation

    International Nuclear Information System (INIS)

    1975-01-01

    A radiographic imaging system for high energy radiation is described utilizing a detector of such radiation and a mask having regions relatively transparent to such radiation and interspersed among regions relatively opaque to such radiation. A relative motion is imparted between the mask and the detector, the detector providing a time varying signal in response to the incident radiation and in response to the relative motion. The time varying signal provides, with the aid of a decoder, an image of a source of such radiation

  7. Radiographic imaging system for high energy radiation

    International Nuclear Information System (INIS)

    Barrett, H.H.

    1976-01-01

    A radiographic imaging system for high energy radiation utilizing a detector of such radiation and a mask having regions relatively transparent to such radiation interspersed among regions relatively opaque to such radiation is described. A relative motion is imparted between the mask and the detector, the detector providing a time varying signal in response to the incident radiation and in response to the relative motion. The time varying signal provides, with the aid of a decoder, an image of a source of such radiation

  8. 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)

  9. Quality of radiograph

    International Nuclear Information System (INIS)

    Abdul Nassir Ibrahim; Azali Muhammad; Ab. Razak Hamzah; Abd. Aziz Mohamed; Mohamad Pauzi Ismail

    2008-01-01

    This chapter discussed on how to get a good radiograph. There are several factors that can make good radiograph such as density of radiograph, the contrast of radiograph, definition of radiograph, the present of artifact and backscattering. All of this factor will discuss detailed on each unit of chapter with some figure, picture to make the reader understand more when read this book. And at the end, the reader will introduce with penetrameter, one of device to determine the level of quality of the radiograph. There are two type of penetrameter like wire type or holes type. This standard must be followed by all the radiographer around the world to produce the good result that is standard and more reliable.

  10. 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.

  11. Algorithms for boundary detection in radiographic images

    International Nuclear Information System (INIS)

    Gonzaga, Adilson; Franca, Celso Aparecido de

    1996-01-01

    Edge detecting techniques applied to radiographic digital images are discussed. Some algorithms have been implemented and the results are displayed to enhance boundary or hide details. An algorithm applied in a pre processed image with contrast enhanced is proposed and the results are discussed

  12. Flat-screen detector systems in skeletal radiology

    International Nuclear Information System (INIS)

    Grampp, S.; Czerny, C.; Krestan, C.; Henk, C.; Heiner, L.; Imhof, H.

    2003-01-01

    Implementation of flat-panel detectors and digital integration of the technique instead of the use of conventional radiographs leads to a shortening of the work process. With flat-panel technology the image production process is shortened by more than 30%. Major advantages in the implementation of integrated RIS, PACS and flat-panel detector system are increases in quality because most mistakes in picture labeling can be avoided, easier handling without the need for cassettes, and the possibility of image post-processing. The diagnostic quality of the images in the field of musculoskeletal radiology is, in comparison to conventional radiographs, at least adequate and in most cases markedly improved with a marked reduction in radiation exposure of around 30-50%. With respect to the numerous advantages of the digital techniques and especially flat-panel technology there is a very high likelihood that conventional radiographs will be substituted in the coming years, even though the cost of the new technology is currently significantly higher compared to conventional systems. (orig.) [de

  13. Efficacy of conventional and digital radiographic imaging methods for diagnosis of simulated external root resorption Eficácia dos métodos radiográficos convencional e digital no diagnóstico de reabsorções radiculares simuladas

    Directory of Open Access Journals (Sweden)

    Vânia Portela Ditzel Westphalen

    2004-06-01

    Full Text Available This in vitro study evaluated and compared the efficacy of conventional (Kodak F-speed (Insight, Kodak and a digital (DRS Gnatus System, Gnatus radiographic imaging for diagnosis of simulated external root resorption cavities. Human mandibles containing teeth were covered with bovine muscle slices in order to simulate the soft tissues. Nine teeth out of each group of teeth were investigated. Initially, three periapical radiographs of each tooth were taken using a tube shift technique with mesial and distal angulations in both methods. All teeth were subsequently extracted and had 0.7 and 1.0-mm deep cavities prepared on their buccal, mesial and distal surfaces at the cervical, middle and apical thirds. Steel cylinder burs (DORMER® - HSS with 0.7 and 1.0-mm diameter were used. Each tooth was replaced on its socket and new radiographs were taken. Three examiners, an endodontist (1, a radiologist (2 and a general dentist (3, evaluated the images. Results were compared by z-test and showed a higher number of cavities detected by the digital method compared to the conventional, regardless of the deepness of the cavity. In decreasing order, examiners 2, 3 and 1 exhibited different potentials of detection of cavities with the conventional method. Examiners 1 and 3 exhibited superior potential than examiner 2 for detection of cavities of different sizes with the digital method.O presente estudo visou avaliar e comparar, in vitro, a eficácia dos métodos radiográficos convencional (filmes de grupos de sensibilidade E/F Kodak Insight e digital (Sistema Gnatus DRS, no diagnóstico de cavidades simulando reabsorções radiculares externas, em dentes contidos em mandíbulas humanas secas com músculo bovino simulando o tecido mole. As variáveis consideradas foram: tamanhos das cavidades e examinadores envolvidos. Foram utilizadas nove unidades de cada grupo dentário, incisivos (central e lateral, caninos, pré-molares e molares, sem lesões periapicais

  14. Digital Imaging. Chapter 16

    Energy Technology Data Exchange (ETDEWEB)

    Clunie, D. [CoreLab Partners, Princeton (United States)

    2014-09-15

    The original means of recording X ray images was a photographic plate. Nowadays, all medical imaging modalities provide for digital acquisition, though globally, the use of radiographic film is still widespread. Many modalities are fundamentally digital in that they require image reconstruction from quantified digital signals, such as computed tomography (CT) and magnetic resonance imaging (MRI)

  15. Simultaneous high speed digital cinematographic and X-ray radiographic imaging of a intense multi-fluid interaction with rapid phase changes

    Energy Technology Data Exchange (ETDEWEB)

    Hansson, Roberta Concilio; Park, Hyun Sun; Dinh, Truc-Nam [Royal Institute of Technology, Division of Nuclear Power Safety, AlbaNova, Stockholm SE-106 91 (Sweden)

    2009-04-15

    As typical for the study of the vapor explosions, the qualitative and quantitative understanding of the phenomena requires visualization of both material and interface dynamics. A new approach to multi-fluid multiphase visualization is presented with the focus on the development of a synchronized high-speed visualization by digital cinematography and X-ray radiography. The developed system, named SHARP (simultaneous high-speed acquisition of X-ray radiography and photography), and its image processing methodology, directed to an image synchronization procedure and a separate quantification of vapor and molten material dynamics, is presented in this paper. Furthermore, we exploit an intrinsic property of the X-ray radiation, namely the differences in linear mass attenuation coefficients over the beam path through a multi-component system, to characterize the evolution of molten material distribution. Analysis of the data obtained by the SHARP system and image processing procedure developed granted new insights into the physics of the vapor explosion phenomena, as well as, quantitative information of the associated dynamic micro-interactions. (author)

  16. Implementation of a patient dose monitoring system in conventional digital X-ray imaging: initial experiences

    Energy Technology Data Exchange (ETDEWEB)

    Heilmaier, Christina; Zuber, Niklaus; Weishaupt, Dominik [Stadtspital Triemli Zurich, Department of Radiology and Nuclear Medicine, Zurich (Switzerland)

    2017-03-15

    The purpose was to report on the initial experience after implementation of a patient dose-monitoring system in conventional X-ray imaging. A dose-monitoring system collected dose data relating to different radiographs (one projection) and studies (two or more projections). Images were acquired on digital X-ray systems equipped with flat-panel detectors. During period 1, examinations were performed in a routine fashion in 12,614 patients. After period 1, technical modifications were performed and radiographers underwent training in radiation protection. During period 2, examinations were performed in 14,514 patients, and the radiographers were advised to read dose data after each radiograph/study. Dose data were compared by means of kerma area product (KAP, gray x centimetre squared) and entrance surface air kerma (ESAK, milligray). During period 1, 13,955 radiographs and 8,466 studies were performed, and in period 2 16,090 radiographs and 10,389 studies. In period 2, KAP values for radiographs were an average of 25 % lower and for studies 7 % lower, and ESAK values for radiographs were 24 % lower and for studies 5 % lower. The reduction in KAP was significant in 8/13 radiographs and in 6/14 studies, and the reduction in ESAK was significant in 6/13 radiographs and 5/14 studies. Implementation of a patient dose-monitoring system in conventional X-ray imaging allows easy data collection, supports dose reduction efforts, and may increase radiographers' dose awareness. (orig.)

  17. 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

  18. Semiconductor Detectors

    International Nuclear Information System (INIS)

    Cortina, E.

    2007-01-01

    Particle detectors based on semiconductor materials are among the few devices used for particle detection that are available to the public at large. In fact we are surrounded by them in our daily lives: they are used in photoelectric cells for opening doors, in digital photographic and video camera, and in bar code readers at supermarket cash registers. (Author)

  19. Fast radiographic systems

    International Nuclear Information System (INIS)

    Domanus, J.C.

    1984-08-01

    Industrial radiography can be performed with shorter exposure times, when instead of X-ray film with lead intensifying screens the radiographic paper with fluorescent screen is used. With paper radiography one can obtain lower material, equipment, and labor costs, shorter exposure and processing times, and easier radiation protection. The speed of the radiographic inspection can also be increased by the use of fluorometallic intensifying screens together with a special brand of X-ray film. Before accepting either of the two fast radiographic systems one must be sure that they can produce radiographs of adequate image quality. Therefore an investigation was performed on that subject using ISO wire IQI's and ASTM penetrameters. The radiographic image quality was tested for aluminium and steel up to 30 mm thick using various brands of radiographic paper and X-ray film with fluorometallic screens and comparing them with fast X-ray films with lead screens. Both systems give satisfactory results. (author)

  20. A feasibility study of projection-based energy weighting based on a photon-counting detector in contrast-enhanced digital subtraction mammography: a simulation study

    International Nuclear Information System (INIS)

    Choi, Sunghoon; Lee, Seungwan; Choi, Yuna; Kim, Heejoung

    2014-01-01

    Contrast media, such as iodine and gadolinium, are generally used in digital subtraction mammography to enhance the contrast between target and background materials. In digital subtraction mammography, where one image (with contrast medium) is subtracted from another (anatomical background) to facilitate visualization of the tumor structure, tumors can be more easily distinguished after the injection of a contrast medium. In order to have more an effective method to increase the contrast-to-noise ratio (CNR), we applied a projection-based energy-weighting method. The purpose of this study is to demonstrate the feasibility of using the projection-based energy-weighting method in digital subtraction mammography. Unlike some other previous studies, we applied the projection-based energy-weighting method to more practical mammography conditions by using the Monte Carlo method to simulate four different iodine solutions embedded in a breast phantom comprised of 50% adipose and 50% glandular tissues. We also considered an optimal tube voltage and anode/filter combination in digital iodine contrast media mammography in order to maximize the figure-of-merit (FOM). The simulated source energy was from 20 to 45 keV to prevent electronic noise and include the k-edge energy of iodine (33.2 keV). The results showed that the projection-based energy-weighting improved the CNR by factors of 1.05 - 1.86 compared to the conventionally integrated images. Consequently, the CNR of digital subtraction mammography images can be improved by using projection-based energy-weighting with photon-counting detectors.

  1. A feasibility study of projection-based energy weighting based on a photon-counting detector in contrast-enhanced digital subtraction mammography: a simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sunghoon; Lee, Seungwan; Choi, Yuna; Kim, Heejoung [Yonsei University, Wonju (Korea, Republic of)

    2014-06-15

    Contrast media, such as iodine and gadolinium, are generally used in digital subtraction mammography to enhance the contrast between target and background materials. In digital subtraction mammography, where one image (with contrast medium) is subtracted from another (anatomical background) to facilitate visualization of the tumor structure, tumors can be more easily distinguished after the injection of a contrast medium. In order to have more an effective method to increase the contrast-to-noise ratio (CNR), we applied a projection-based energy-weighting method. The purpose of this study is to demonstrate the feasibility of using the projection-based energy-weighting method in digital subtraction mammography. Unlike some other previous studies, we applied the projection-based energy-weighting method to more practical mammography conditions by using the Monte Carlo method to simulate four different iodine solutions embedded in a breast phantom comprised of 50% adipose and 50% glandular tissues. We also considered an optimal tube voltage and anode/filter combination in digital iodine contrast media mammography in order to maximize the figure-of-merit (FOM). The simulated source energy was from 20 to 45 keV to prevent electronic noise and include the k-edge energy of iodine (33.2 keV). The results showed that the projection-based energy-weighting improved the CNR by factors of 1.05 - 1.86 compared to the conventionally integrated images. Consequently, the CNR of digital subtraction mammography images can be improved by using projection-based energy-weighting with photon-counting detectors.

  2. Radiographic constant exposure technique

    DEFF Research Database (Denmark)

    Domanus, Joseph Czeslaw

    1985-01-01

    The constant exposure technique has been applied to assess various industrial radiographic systems. Different X-ray films and radiographic papers of two producers were compared. Special attention was given to fast film and paper used with fluorometallic screens. Radiographic image quality...... was tested by the use of ISO wire IQI's and ASTM penetrameters used on Al and Fe test plates. Relative speed and reduction of kilovoltage obtained with the constant exposure technique were calculated. The advantages of fast radiographic systems are pointed out...

  3. Visual simulation of radiographs

    International Nuclear Information System (INIS)

    Laguna, G.

    1985-01-01

    A method for computer simulation of radiographs has been added to the LLNL version of the solid modeler TIPS-1 (Technical Information Processing System-1). This new tool will enable an engineer to compare an actual radiograph of a solid to its computer-generated counterpart. The appearance of discrepancies between the two can be an indication of flaws in the solid object. Simulated radiographs can also be used to preview the placement of x-ray sources to focus on areas of concern before actual radiographs are made

  4. Fabrication and characterization of a 32 x 32 array digital Si-PIN X-ray detector for a single photon counting image sensor

    International Nuclear Information System (INIS)

    Seo, Jungho; Kim, Jinyoung; Lim, Hyunwoo; Park, Jingoo; Lee, Songjun; Kim, Bonghoe; Jeon, Sungchae; Huh, Young

    2010-01-01

    A Si-PIN X-ray detector for digital x-ray imaging with single photon counting capability has been fabricated and characterized. It consists of an array of 32 x 32 pixels with an area of 80 x 80 μm 2 . An extrinsic gettering process was performed to reduce the leakage current by removing the impurities and defects from the X-ray detector's Si substrate. Multiple guard-rings (MGRs) and metal filed plates (MFPs) techniques were adopted to reduce the leakage current and to improve the breakdown performance. The simulation verified that the breakdown voltage was improved with the MGRs and that the leakage current was significantly reduced with the MFPs. The electrical properties, such as the leakage current and the breakdown voltage, of the Si-PIN X-ray detector were characterized. The extrinsic gettering process played a significant role in reducing the leakage current, and a leakage current lower than 60 pA could be achieved at 100 V dc .

  5. Automating the radiographic NDT process

    International Nuclear Information System (INIS)

    Aman, J.K.

    1988-01-01

    Automation, the removal of the human element in inspection has not been generally applied to film radiographic NDT. The justification for automation is not only productivity but also reliability of results. Film remains in the automated system of the future because of its extremely high image content, approximately 3x10 (to the power of nine) bits per 14x17. This is equivalent to 2200 computer floppy disks parts handling systems and robotics applied for manufacturing and some NDT modalities, should now be applied to film radiographic NDT systems. Automatic film handling can be achieved with the daylight NDT film handling system. Automatic film processing is becoming the standard in industry and can be coupled to the daylight system. Robots offer the opportunity to automate fully the exposure step. Finally, a computer aided interpretation appears on the horizon. A unit which laser scans a 14x27 (inch) film in 6-8 seconds can digitize film in information for further manipulation and possible automatic interrogations (computer aided interpretation). The system called FDRS (for film digital radiography system) is moving toward 50 micron (16 lines/mm) resolution. This is believed to meet the need of the majority of image content needs. (Author). 4 refs.; 21 figs

  6. Radiographic and Clinical Analysis of Lateral Epicondylitis.

    Science.gov (United States)

    Shillito, Matthew; Soong, Maximillian; Martin, Nicholas

    2017-06-01

    The literature suggests that radiographs may be unnecessary in the initial evaluation of lateral epicondylitis because treatment is rarely altered as a result of the radiographic findings. The most commonly reported radiographic finding is calcification at the lateral epicondyle. Our goal was to perform a quantitative and qualitative analysis of this finding to determine its importance and possible relationship with various clinical factors and patient-reported measures. All patients diagnosed with lateral epicondylitis by a single surgeon during a 5-year period were retrospectively reviewed. Age, sex, laterality, hand dominance, pain visual analog scale, duration of symptoms, Quick-Disability of the Arm, Shoulder, and Hand questionnaire score, and history of steroid injection were recorded. Calcifications on standard elbow radiographs, acquired digitally and viewed at 200% magnification on a 24-inch monitor, were characterized by size and relationship with the lateral epicondyle. We reviewed 245 patients diagnosed with lateral epicondylitis. A total of 115 elbows (47%) demonstrated lateral epicondyle calcifications. Patients with and without calcifications were similar with regard to clinical factors, as were patients with larger or smaller lesions. Eighty-five elbows (35%) had additional radiographic findings. Treatment was not altered by the radiographic findings in any case. Lateral epicondyle calcifications are much more common in lateral epicondylitis than previously reported, possibly owing to modern digital radiography and magnification, although they do not appear to be related to clinical factors including patient-reported measures. Thus, patients and surgeons should be careful to avoid overinterpretation of such findings. Although radiographs may be helpful in ruling out additional pathology, we did not find other clinically important contributions to the initial evaluation and management of this condition, and thus we do not recommend their routine use

  7. 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.

  8. Black Lung Benefits Act: standards for chest radiographs. Direct final rule; request for comments.

    Science.gov (United States)

    2013-06-13

    Physicians and adjudicators use chest radiographs (X-rays) as a tool in evaluating whether a coal miner suffers from pneumoconiosis (black lung disease). Accordingly, the Department's regulations implementing the Black Lung Benefits Act allow the submission of radiographs in connection with benefit claims and set out quality standards for their performance. These standards are currently limited to film radiographs. In recent years, many medical facilities have phased out film radiography in favor of digital radiography. This direct final rule updates the existing film-radiograph standards and provides parallel standards for digital radiographs. This rule also updates outdated terminology and removes certain obsolete provisions.

  9. Economical stabilized scintillation detector

    International Nuclear Information System (INIS)

    Anshakov, O.M.; Chudakov, V.A.; Gurinovich, V.I.

    1983-01-01

    An economical scintillation detector with the stabilization system of an integral type is described. Power consumed by the photomultiplier high-voltage power source is 40 mW, energy resolution is not worse than 9%. The given detector is used in a reference detector of a digital radioisotope densimeter for light media which is successfully operating for several years

  10. The front-end analog and digital signal processing electronics for the drift chambers of the Stanford Large Detector

    International Nuclear Information System (INIS)

    Haller, G.M.; Freytag, D.R.; Fox, J.; Olsen, J.; Paffrath, L.; Yim, A.; Honma, A.

    1990-10-01

    The front-end signal processing electronics for the drift-chambers of the Stanford Large Detector (SLD) at the Stanford Linear Collider is described. The system is implemented with printed-circuit boards which are shaped for direct mounting on the detector. Typically, a motherboard comprises 64 channels of transimpedance amplification and analog waveform sampling, A/D conversion, and associated control and readout circuitry. The loaded motherboard thus forms a processor which records low-level wave forms from 64 detector channels and transforms the information into a 64 k-byte serial data stream. In addition, the package performs calibration functions, measures leakage currents on the wires, and generates wire hit patterns for triggering purposes. The construction and operation of the electronic circuits utilizing monolithic, hybridized, and programmable components are discussed

  11. First realization of a tracking detector for high energy physics experiments based on Josephson digital readout circuitry

    CERN Document Server

    Pagano, S; Esposito, A P; Mukhanov, O; Rylov, S

    1999-01-01

    We have designed and realized a prototype of a high energy particle microstrip detector with Josephson readout circuits. The key features of this device are: minimum ionizing particle sensitivity, due to the use of semiconductive sensors, fast speed and radiation hardness, due to the use of superconductive circuitry, and current discrimination, which allows the use of several types of semiconductors as detector (Si, GaAs, CVD-diamond) without loss in performances. The Josephson circuitry, made by a combination of RSFQ and latching logic gates, realizes an 8-bit current discriminator and parallel to serial converter and can be directly interfaced to room temperature electronics. This device, which is designed for application as vertex detector for the Compass and LHC-B accelerator experiments, has been tested with small radioactive sources acid will undergo to a test beam at the CERN SPS facility with 24 GeV/c protons. Current results and future perspectives will be reported. (11 refs).

  12. The one-leg standing radiograph

    OpenAIRE

    Pinsornsak, P.; Naratrikun, K.; Kanitnate, S.; Sangkomkamhang, T.

    2016-01-01

    Objectives The purpose of this study was to compare the joint space width between one-leg and both-legs standing radiographs in order to diagnose a primary osteoarthritis of the knee. Methods Digital radiographs of 100 medial osteoarthritic knees in 50 patients were performed. The patients had undergone one-leg standing anteroposterior (AP) views by standing on the affected leg while a both-legs standing AP view was undertaken while standing on both legs. The severity of the osteoarthritis wa...

  13. Image rejects/retakes--radiographic challenges.

    Science.gov (United States)

    Waaler, D; Hofmann, B

    2010-01-01

    A general held position among radiological personnel prior to digitalisation was that the problem of image rejects/retakes should more or less vanish. However, rejects/retakes still impose several challenges within radiographic imaging; they occupy unnecessary resources, expose patients to unnecessary ionizing radiation and may also indicate suboptimal quality management. The latter is the main objective of this paper, which is based on a survey of international papers published both for screen/film and digital technology. The digital revolution in imaging seems to have reduced the percentage of image rejects/retakes from 10-15 to 3-5 %. The major contribution to the decrease appears to be the dramatic reduction of incorrect exposures. At the same time, rejects/retakes due to lack of operator competence (positioning, etc.) are almost unchanged, or perhaps slightly increased (due to lack of proper technical competence, incorrect organ coding, etc.). However, the causes of rejects/retakes are in many cases defined and reported with reference to radiographers' subjective evaluations. Thus, unless radiographers share common views on image quality and acceptance criteria, objective measurements and assessments of reject/retake rates are challenging tasks. Interestingly, none of the investigated papers employs image quality parameters such as 'too much noise' as categories for rejects/retakes. Surprisingly, no reject/retake analysis seems yet to have been conducted for direct digital radiography departments. An increased percentage of rejects/retakes is related to 'digital skills' of radiographers and therefore points to areas for extended education and training. Furthermore, there is a need to investigate the inter-subjectivity of radiographers' perception of, and attitude towards, both technical and clinical image quality criteria. Finally, there may be a need to validate whether reject/retake rate analysis is such an effective quality indicator as has been asserted.

  14. Image rejects/retakes-radiographic challenges

    International Nuclear Information System (INIS)

    Waaler, D.; Hofmann, B.

    2010-01-01

    A general held position among radiological personnel prior to digitalisation was that the problem of image rejects/retakes should more or less vanish. However, rejects/retakes still impose several challenges within radiographic imaging; they occupy unnecessary resources, expose patients to unnecessary ionizing radiation and may also indicate suboptimal quality management. The latter is the main objective of this paper, which is based on a survey of international papers published both for screen/film and digital technology. The digital revolution in imaging seems to have reduced the percentage of image rejects/retakes from 10-15 to 3-5%. The major contribution to the decrease appears to be the dramatic reduction of incorrect exposures. At the same time, rejects/retakes due to lack of operator competence (positioning, etc.) are almost unchanged, or perhaps slightly increased (due to lack of proper technical competence, incorrect organ coding, etc.). However, the causes of rejects/retakes are in many cases defined and reported with reference to radiographers' subjective evaluations. Thus, unless radiographers share common views on image quality and acceptance criteria, objective measurements and assessments of reject/retake rates are challenging tasks. Interestingly, none of the investigated papers employs image quality parameters such as 'too much noise' as categories for rejects/retakes. Surprisingly, no reject/retake analysis seems yet to have been conducted for direct digital radiography departments. An increased percentage of rejects/retakes is related to 'digital skills' of radiographers and therefore points to areas for extended education and training. Furthermore, there is a need to investigate the inter subjectivity of radiographers' perception of, and attitude towards, both technical and clinical image quality criteria. Finally, there may be a need to validate whether reject/retake rate analysis is such an effective quality indicator as has been asserted

  15. 50 μm pixel pitch wafer-scale CMOS active pixel sensor x-ray detector for digital breast tomosynthesis

    International Nuclear Information System (INIS)

    Zhao, C; Kanicki, J; Konstantinidis, A C; Zheng, Y; Speller, R D; Anaxagoras, T

    2015-01-01

    Wafer-scale CMOS active pixel sensors (APSs) have been developed recently for x-ray imaging applications. The small pixel pitch and low noise are very promising properties for medical imaging applications such as digital breast tomosynthesis (DBT). In this work, we evaluated experimentally and through modeling the imaging properties of a 50 μm pixel pitch CMOS APS x-ray detector named DynAMITe (Dynamic Range Adjustable for Medical Imaging Technology). A modified cascaded system model was developed for CMOS APS x-ray detectors by taking into account the device nonlinear signal and noise properties. The imaging properties such as modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) were extracted from both measurements and the nonlinear cascaded system analysis. The results show that the DynAMITe x-ray detector achieves a high spatial resolution of 10 mm −1 and a DQE of around 0.5 at spatial frequencies  <1 mm −1 . In addition, the modeling results were used to calculate the image signal-to-noise ratio (SNR i ) of microcalcifications at various mean glandular dose (MGD). For an average breast (5 cm thickness, 50% glandular fraction), 165 μm microcalcifications can be distinguished at a MGD of 27% lower than the clinical value (∼1.3 mGy). To detect 100 μm microcalcifications, further optimizations of the CMOS APS x-ray detector, image aquisition geometry and image reconstruction techniques should be considered. (paper)

  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. Legalities of the radiograph

    International Nuclear Information System (INIS)

    Bundy, A.L.

    1988-01-01

    The radiograph itself plays a major role in medical malpractice cases. Also, many questions arise concerning the rights to and storage of x-ray films. These issues are addressed in this chapter. To keep the terminology simple, the word radiograph represents all imaging documentation on hard copy film (x-rays, nuclear medicine, computer-assisted studies, ultrasound, and magnetic resonance imaging)

  18. 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:...

  19. Improvements of visual X-ray inspection with optimized digital detector technology. Faster and more reliable inspection with High Dynamic Radiology (HDR)

    International Nuclear Information System (INIS)

    Bavendiek, Klaus

    2010-01-01

    Improvements in speed and contrast resolution of Digital Detector Arrays (DDA) and significant higher power of X-Ray tubes in combination with a small focal spot open the door to an improved visual inspection of castings for automotive and aerospace applications. The result is a film-like image quality of castings in a live view. For the new image quality the x-ray parameter have to be optimized in energy and the subject contrast has to be increased to avoid that flaws are covered by the noise in the image. HDR - high dynamic radiology - expands the local contrast in the image and transfers the grey values to the range the human inspector can separate. Due to the movement in the image the inspector gets a glas-like impression of the object and the flaws allowing him to do a decision about the 3D position of a flaw in the object. (orig.)

  20. Development of optimized techniques and requirements for computer enhancement of structural weld radiographs. Volume 1: Technical report

    Science.gov (United States)

    Adams, J. R.; Hawley, S. W.; Peterson, G. R.; Salinger, S. S.; Workman, R. A.

    1971-01-01

    A hardware and software specification covering requirements for the computer enhancement of structural weld radiographs was considered. Three scanning systems were used to digitize more than 15 weld radiographs. The performance of these systems was evaluated by determining modulation transfer functions and noise characteristics. Enhancement techniques were developed and applied to the digitized radiographs. The scanning parameters of spot size and spacing and film density were studied to optimize the information content of the digital representation of the image.

  1. Digital radiographic evaluation of optical density of porcelains used for fabrication of inlay/onlay prosthesis Avaliação da densidade óptica de porcelanas usadas para confecção de próteses inlay/onlay por meio de radiografia digital

    Directory of Open Access Journals (Sweden)

    Júlio Cezar de Melo Castilho

    2006-01-01

    Full Text Available The purpose of this article was to compare the mean value of optical density of four porcelains commonly used for fabrication of inlay/onlay prostheses using direct digital radiograph. The sample consisted of 20 2-mm thick porcelain specimens (measured by digital pachymeter: Empress (Ivoclair, Simbios (Degussa, Vita Omega 900 and Vitadur Alpha (Vita Zahnfabrik. The values of optical density of the specimens were expressed in millimeters aluminum equivalent (mm eq Al. The samples were X-rayed using two charge coupled devices (CCD - RVG (Trophy - Visualix (Gendex and a phosphor plate system - Digora (Soredex. The optical density reading was performed with Image Tool 1.28 in a total of 110 measurements. Statistical analysis showed that there were statistically significant differences in all materials studied (p Objetivo desse trabalho é comparar valores médios de densidade óptica de quatro porcelanas comumente utilizadas para confecção de inlay/onlay por meio da densidade óptica usando radiografia digital. A amostra constou de 20 corpos de prova com espessura de 2mm (mensurados em paquímetro digital das porcelanas: Empress (Ivoclair, Simbios (Degussa, Vita Omega 900 e Vitadur Alpha (Vita Zahnfabrik. Os valores de densidade óptica das amostras foram expressos em milímetros equivalente em alumínio (mm eq Al. Os espécimes foram radiografados, utilizando dois sistemas de dispositivo de carga acoplada (CCD - RVG (Trophy - Visualix (Gendex e um sistema de placa de fósforo - Digora (Soredex. A leitura da densidade óptica foi realizada no programa Image Tool 1.28 totalizando 110 medições. As leituras de densidade ópticas foram feitas no programa Image Tool 1.28 totalizando 110 mensurações. A análise estatística demonstrou que houve diferença estatisticamente significante entre a densidade óptica das porcelanas estudadas independentemente do sistema de radiografia empregado (p < 0,05. A porcelana Omega 900 obteve 1,8988mmeq

  2. Data acquisition system for radiographic imaging

    International Nuclear Information System (INIS)

    Lanza, R.C.; Votano, J.R.; Russ, T.

    1992-01-01

    This patent describes a continuous data acquisition system for radiographic imaging without interrupting acquisition activity the acquisition system. It comprises at least two memory means for storing radiographic data from a radiation detector wherein each of the memory means having a plurality of addressable memory locations and each of the memory means are such that the locations of the memory means correspond to spatial locations in the radiation detector; logic control means for sensing radiographic data transmitted by the radiation detector, for selecting one of the memory means for storage of the data, for transferring data to the selected memory means, and for switching form one memory means to another memory means according to a predefined schedule and according to memory capacity level, the logic control means further comprising a logic device which receives data and increments the contents of locations in a memory means in response to such data; and interface control means for reading data from one or the other memory means when such memory means is not actively acquiring data such that data can be acquired continuously by the system

  3. Producing quality radiographic images

    International Nuclear Information System (INIS)

    Cullinan, A.M.

    1987-01-01

    This book gives an overview of physics, equipment, imaging, and quality assurance in the radiology department. The chapters are laid out with generous use of subheads to allow for quick reference, Points are illustrated with clear, uncluttered line diagrams and well-produced images. The accompanying explanations are miniature lessons by themselves. Inserted at various points throughout the text are important notes that highlight key concepts. The chapter ''Image Evaluation and Application of Radiographic Principles'' present a systematic approach to evaluating radiographs and contains several sample radiographs to illustrate the points made

  4. Computational simulation of radiographic film

    International Nuclear Information System (INIS)

    Goncalves, Elicardo A. de S.; Santos, Marcio H. dos; Anjos, Marcelino J.; Oliveira, Luis F. de

    2013-01-01

    The composition of a radiographic film gives its values of speed, spatial resolution and base density. The technical knowledge allows to predict how a film with a known composition works, and simulate how this film will work with changes in composition and exposure. In this paper, characterization of films composed by different emulsions was realized, in a way to know the characteristic curve, and to study how the format, organization and concentration of silver salt crystals set the radiographic film images.This work aims to increase an existing simulator, where parallel programming was used to simulate X-ray fluorescence processes. The setup of source and X-ray interactions with objects stills the same, and the detector constructed in this work was placed to form images. At first, considering the approach that the film is a square matrix where each element has a specific quantity of silver grains, that each grain fills a specific area, and that each interaction to radiation transforms a salt silver grain in to metallic silver grain (black grain), we have a blackening standard, and it should show how is the behavior of a optic density in a specific area of the film. Each matrix element has a degree of blackening, and it is proportional to the black grains area. (author)

  5. Dose optimization for dual-energy contrast-enhanced digital mammography based on an energy-resolved photon-counting detector: A Monte Carlo simulation study

    Science.gov (United States)

    Lee, Youngjin; Lee, Seungwan; Kang, Sooncheol; Eom, Jisoo

    2017-03-01

    Dual-energy contrast-enhanced digital mammography (CEDM) has been used to decompose breast images and improve diagnostic accuracy for tumor detection. However, this technique causes an increase of radiation dose and an inaccuracy in material decomposition due to the limitations of conventional X-ray detectors. In this study, we simulated the dual-energy CEDM with an energy-resolved photon-counting detector (ERPCD) for reducing radiation dose and improving the quantitative accuracy of material decomposition images. The ERPCD-based dual-energy CEDM was compared to the conventional dual-energy CEDM in terms of radiation dose and quantitative accuracy. The correlation between radiation dose and image quality was also evaluated for optimizing the ERPCD-based dual-energy CEDM technique. The results showed that the material decomposition errors of the ERPCD-based dual-energy CEDM were 0.56-0.67 times lower than those of the conventional dual-energy CEDM. The imaging performance of the proposed technique was optimized at the radiation dose of 1.09 mGy, which is a half of the MGD for a single view mammogram. It can be concluded that the ERPCD-based dual-energy CEDM with an optimal exposure level is able to improve the quality of material decomposition images as well as reduce radiation dose.

  6. Characterization of a detector chain using a FPGA-based time-to-digital converter to reconstruct the three-dimensional coordinates of single particles at high flux

    Science.gov (United States)

    Nogrette, F.; Heurteau, D.; Chang, R.; Bouton, Q.; Westbrook, C. I.; Sellem, R.; Clément, D.

    2015-11-01

    We report on the development of a novel FPGA-based time-to-digital converter and its implementation in a detection chain that records the coordinates of single particles along three dimensions. The detector is composed of micro-channel plates mounted on top of a cross delay line and connected to fast electronics. We demonstrate continuous recording of the timing signals from the cross delay line at rates up to 4.1 × 106 s-1 and three-dimensional reconstruction of the coordinates up to 3.2 × 106 particles per second. From the imaging of a calibrated structure we measure the in-plane resolution of the detector to be 140(20) μm at a flux of 3 × 105 particles per second. In addition, we analyze a method to estimate the resolution without placing any structure under vacuum, a significant practical improvement. While we use UV photons here, the results of this work apply to the detection of other kinds of particles.

  7. Dose optimization for dual-energy contrast-enhanced digital mammography based on an energy-resolved photon-counting detector: A Monte Carlo simulation study

    International Nuclear Information System (INIS)

    Lee, Youngjin; Lee, Seungwan; Kang, Sooncheol; Eom, Jisoo

    2017-01-01

    Dual-energy contrast-enhanced digital mammography (CEDM) has been used to decompose breast images and improve diagnostic accuracy for tumor detection. However, this technique causes an increase of radiation dose and an inaccuracy in material decomposition due to the limitations of conventional X-ray detectors. In this study, we simulated the dual-energy CEDM with an energy-resolved photon-counting detector (ERPCD) for reducing radiation dose and improving the quantitative accuracy of material decomposition images. The ERPCD-based dual-energy CEDM was compared to the conventional dual-energy CEDM in terms of radiation dose and quantitative accuracy. The correlation between radiation dose and image quality was also evaluated for optimizing the ERPCD-based dual-energy CEDM technique. The results showed that the material decomposition errors of the ERPCD-based dual-energy CEDM were 0.56–0.67 times lower than those of the conventional dual-energy CEDM. The imaging performance of the proposed technique was optimized at the radiation dose of 1.09 mGy, which is a half of the MGD for a single view mammogram. It can be concluded that the ERPCD-based dual-energy CEDM with an optimal exposure level is able to improve the quality of material decomposition images as well as reduce radiation dose. - Highlights: • Dual-energy mammography based on a photon-counting detector was simulated. • Radiation dose and image quality were evaluated for optimizing the proposed technique. • The proposed technique reduced radiation dose as well as improved image quality. • The proposed technique was optimized at the radiation dose of 1.09 mGy.

  8. Rapidly processable radiographic material

    International Nuclear Information System (INIS)

    Brabandere, L.A. de; Borginon, H.A.; Pattyn, H.A.; Pollet, R.J.

    1981-01-01

    A new rapidly processable radiographic silver halide material is described for use in mammography and non-destructive testing of industrial materials. The radiographic material is used for direct exposure to penetrating radiation without the use of fluorescent-intensifying screens. It consists of a transparent support with a layer of hydrophilic colloid silver halide emulsion on one or both sides. Examples of the preparation of three different silver halide emulsions are given including the use of different chemical sensitizers. These new radiographic materials have good resistance to the formation of pressure marks in rapid processing apparatus and they have improved sensitivity for direct exposure to penetrating radiation compared to conventional radiographic emulsions. (U.K.)

  9. Investigations for the use of the fast digitizers with C6D6 detectors for radiative capture measurements at GELINA

    International Nuclear Information System (INIS)

    Mihailescu, L.C.; Borella, A.; Massimi, C.; Schillebeeckx, P.

    2009-01-01

    The relatively long dead time in conventional data acquisition systems that provide simultaneously the pulse height and the time information for the detected events hinders cross-section measurements with high count rates. This is the case for capture cross-section measurements at the time-of-flight facility GELINA using high radioactive samples or thick samples of materials having strong resonances. Either the high average count rate (e.g. due to the radioactivity of the sample) or the high instantaneous count rate for strong resonances results in a large dead time correction. One solution to reduce the impact of the dead time is the use of a data acquisition system based on fast digitizers. The performances of two commercial digitizers (CAEN N172B and Acqiris DC282), coupled to a C 6 D 6 scintillator, have been tested in terms of pulse height linearity and resolution, dead time and time resolution. The signal processing was done on-line obtaining simultaneously the pulse height and time information for each detected event. With both digitizers a comparable pulse height linearity and resolution has been obtained as with a conventional system. The total dead time of both digital systems is at least a factor 5 shorter than the one for the conventional system. The main difference in performance between the two digitizers is the time resolution. For a relatively large scintillator, a time resolution of about 2 ns has been achieved with the DC282 module and the conventional system while the time resolution was limited to 15 ns with the CAEN N1728B module. For most nuclei a 15 ns time resolution is sufficient to perform resonance shape analysis. Therefore, the CAEN N1728B module can be used for the majority of capture cross-section measurements at GELINA. However, for nuclei with low level density, for which the resolved resonance region extends to the keV-region, a better time resolution is required and the Acqiris DC282 module has to be used.

  10. Radiographic manifestations of hypochondroplasia

    Energy Technology Data Exchange (ETDEWEB)

    Heselson, N G; Cremin, B J [Groote Schuur Hospital, Cape Town (South Africa); Beighton, P

    1979-01-01

    Hypochrondroplasia is an inherited skeletal dysplasia that resembles achondroplasia in mild degree. Radiographic manifestations encountered in 12 affected individuals in South Africa include slight shortening of all segments of the tubular bones, moderate caudal diminution of the lumbar interpedicular distances, increased lumbar lordosis with cacral tilt and distal prolongation of the fibular. Hypochondroplasia can be distinguished from other osteochondrodystrophies such as achondroplasia, pseudo-achondroplasia and metaphyseal chondroplasia by the recognition of it clinical and radiographic manifestations.

  11. 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.

  12. Gout: radiographic findings mimicking infection

    International Nuclear Information System (INIS)

    Rousseau, I.; Raymond-Tremblay, D.; Cardinal, E.; Beauregard, C.G.; Braunstein, E.M.; Saint-Pierre, A.

    2001-01-01

    Objective: To describe radiographic features of gout that may mimic infection. Design and patients: We report five patients with acute bacterial gout who presented with clinical as well as radiological findings mimicking acute bacterial septic arthritis or osteomyelitis. Three patients had delay in the appropriate treatment with the final diagnosis being established after needle aspiration and identification of urate crystals under polarized light microscopy. Two patients underwent digit amputation for not responding to antibiotic treatment and had histological findings confirming the diagnosis of gout. Conclusion: It is important for the radiologist to be aware of the radiological manifestations of acute gout that can resemble infection in order to avoid inappropriate diagnosis and delay in adequate treatment. The definitive diagnosis should rely on needle aspiration and a specific search for urate crystals. (orig.)

  13. 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...

  14. Internet-accessible radiographic database of Vietnam War casualties for medical student education.

    Science.gov (United States)

    Critchley, Eric P; Smirniotopoulos, James G

    2003-04-01

    The purpose of this study was to determine the feasibility of archiving radiographic images from Vietnam era conflict casualties into a personal computer-based electronic database of text and images and displaying the data using an Internet-accessible database for preservation and educational purposes. Thirty-two patient cases were selected at random from a pool of 1,000 autopsy reports in which radiographs were available. A total of 74 radiographs from these cases were digitized using a commercial image scanner and then uploaded into an Internet accessible database. The quality of the digitized images was assessed by administering an image-based test to a group of 12 medical students. No statistically significant (p > 0.05) differences were found between test scores when using the original radiographs versus using the digitized radiographs on the Internet-accessible database. An Internet-accessible database is capable of effectively archiving Vietnam era casualty radiographs for educational purposes.

  15. Radiographic examination of the equine foot

    International Nuclear Information System (INIS)

    Park, R.D.

    1989-01-01

    A complete radiographic examination of the equine foot consists of properly exposed, processed, and positioned radiographs. For radiographic interpretation, in addition to knowing radiographic signs of disease, a knowledge of normal radiographic anatomy and possible insignificant anatomic variations is necessary

  16. Estudio digital radiográfico y densitométrico en mandíbulas de cerdos sometidos a osteotomía con alta y baja velocidad, con refrigeración líquida Digital and densitometric radiographic study in swine jaws subjected to osteotomy using high and low drilling speeds with liquid cooling

    Directory of Open Access Journals (Sweden)

    Lira Marcela Monti

    2010-09-01

    Full Text Available Se evaluó por medio de la radiografía digital y la densitometría, la influencia de un dispositivo de rotación para el corte en el proceso de curación del hueso después de osteotomías en mandíbulas de cerdos, a tiempos controlados. Se realizaron dos secciones transversales en la base de la mandíbula derecha, una con una alta velocidad de rotación y otra por la acción de baja velocidad, ambos con el líquido de irrigación. Tras los tiempos preestablecidos, los animales fueron sacrificados y sus mandíbulas retiradas para los estudios radiográficos y de densitometría radiológica con los sistemas digitales Cromox, Digora y ODR. En los períodos iniciales (7 y 28 días el equivalente a la densitometría en milímetro de aluminio y la media de niveles de gris fueron más altos en la región de osteotomías hechas con alta rotación, y en los períodos finales (60 y 90 días las mayores densitometrías fueron para osteotomías hechas con baja velocidad, lo que indica una mejor cicatrización final del hueso cuando se hace uso de la baja velocidad. El análisis cualitativo del proceso de reparación fue realizado por el ODR, lo que permitió la recopilación de imágenes digitales en color y en tres dimensiones, para la comparación del espesor del hueso con una cuña de aluminio, indicando que en los 28 días de curación del hueso, ya estaba evidente la completa reparación.The influence of the type of rotary cutting instrument on bone repair after osteotomy in swine jaw, was evaluated using digital and densitometric radiographic examinations, at controlled times. Two cross-sectional dissections were made through the base of the right jaw, one using a high speed rotary instrument and the other using low speed, both with liquid cooling. After established periods the animals were sacrificed and their jaws removed for direct and indirect digital radiographic and densitometric studies using the CROMOX, DIGORA and ODR systems. In the initial

  17. Digital mammography

    International Nuclear Information System (INIS)

    Bick, Ulrich; Diekmann, Felix

    2010-01-01

    This state-of-the-art reference book provides in-depth coverage of all aspects of digital mammography, including detector technology, image processing, computer-aided diagnosis, soft-copy reading, digital workflow, and PACS. Specific advantages and disadvantages of digital mammography in comparison to screen-film mammography are thoroughly discussed. By including authors from both North America and Europe, the book is able to outline variations in the use, acceptance, and quality assurance of digital mammography between the different countries and screening programs. Advanced imaging techniques and future developments such as contrast mammography and digital breast tomosynthesis are also covered in detail. All of the chapters are written by internationally recognized experts and contain numerous high-quality illustrations. This book will be of great interest both to clinicians who already use or are transitioning to digital mammography and to basic scientists working in the field. (orig.)

  18. Cone-Beam CT with Flat-Panel-Detector Digital Angiography System: Early Experience in Abdominal Interventional Procedures

    International Nuclear Information System (INIS)