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Sample records for computed radiography analysis

  1. Analysis of the painting 'Gioventu' (Eliseu Visconti) using EDXRF and computed radiography

    Calza, Cristiane [Nuclear Instrumentation Laboratory-COPPE/UFRJ, Rio de Janeiro (Brazil)], E-mail: ccalza@lin.ufrj.br; Oliveira, Davi F.; Souza Rocha, Henrique de [Nuclear Instrumentation Laboratory-COPPE/UFRJ, Rio de Janeiro (Brazil); Pedreira, Andrea [National Museum of Fine Arts, Rio de Janeiro (Brazil); Tadeu Lopes, Ricardo [Nuclear Instrumentation Laboratory-COPPE/UFRJ, Rio de Janeiro (Brazil)

    2010-04-15

    In this work, the painting 'Gioventu' (Eliseu Visconti, 1898) was analyzed by means of energy dispersive X-ray fluorescence and computed radiography. A portable EDXRF system was employed to identify the pigments used by the artist: yellow, red and brown ocher; umber; vermilion; cobalt blue; lead white and viridian (or chromium oxide). The CR analysis revealed that the painting was in a good state of conservation and also a previous composition hidden under the painting.

  2. Pediatric musculoskeletal computed radiography

    Background. In conventional radiography, a film-screen system serves as the X-ray detector and the film also functions as an archival and display medium. Unlike film-screen radiography, these functions are uncoupled in computed radiography (CR). CR uses conventional radiographic equipment to expose an image on a storage phosphor plate instead of a film-screen combination. Objective. To review the basic concepts of CR and to provide a background for discussion of specific musculoskeletal applications of CR in children. Materials and methods. Various aspects of musculoskeletal CR in children are presented based on our 4 years' experience and a review of the literature. Results. A greater amount of scatter capture occurs with storage phosphor CR than with a film-screen system in the 70- to 120-kVp range. This is attributed to a lower K-absorption edge of barium in the barium fluorohalide (BaFBr) compound used in the imaging plate. A significant reduction of scatter to primary radiation, improvement in bony trabecular sharpness, and improvement in line pair resolution can be achieved in pediatric musculoskeletal imaging using an air gap without an increase in the skin entrance dose as compared to the non-grid table top technique. With CR, in addition to proper radiographic exposure technique, one needs to preprogram and select the optimal processing technique for each anatomic region, projection and age group of the child. Conclusion. The main advantages of CR in pediatric musculoskeletal imaging consist of a reduction in radiation dose for many applications, improved contrast resolution, near elimination of repeat radiographs related to exposure errors, and digital processing capabilities for image enhancement, storage, retrieval, display and transmission. The current limitations of CR include the moderately high start-up cost, the long learning curve to produce optimal films, and the reduced spatial resolution. (orig.). With 8 figs., 2 tabs

  3. Computational radiology in skeletal radiography

    Peloschek, Ph.; Nemec, S. [Computational Image Analysis and Radiology Lab (CIR), Department of Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Widhalm, P. [Computational Image Analysis and Radiology Lab (CIR), Department of Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Pattern Recognition and Image Processing Group, Department of Computer Aided Automation, Vienna University of Technology, Wiedner Hauptstrasse 8-10/020, A-1040 Vienna (Austria); Donner, R. [Computational Image Analysis and Radiology Lab (CIR), Department of Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Pattern Recognition and Image Processing Group, Department of Computer Aided Automation, Vienna University of Technology, Wiedner Hauptstrasse 8-10/020, A-1040 Vienna (Austria); Institute for Computer Graphics and Vision, Graz University of Technology, Inffeldgasse 16, A-8010 Graz (Austria); Birngruber, E. [Computational Image Analysis and Radiology Lab (CIR), Department of Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Thodberg, H.H. [Visiana Aps, Sollerodvej 57C, DK-2840 Holte (Denmark); Kainberger, F. [Computational Image Analysis and Radiology Lab (CIR), Department of Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Langs, G. [Computational Image Analysis and Radiology Lab (CIR), Department of Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria)], E-mail: georg.langs@meduniwien.ac.at

    2009-11-15

    Recent years have brought rapid developments in computational image analysis in musculo-skeletal radiology. Meanwhile the algorithms have reached a maturity that makes initial clinical use feasible. Applications range from joint space measurement to erosion quantification, and from fracture detection to the assessment of alignment angles. Current results of computational image analysis in radiography are very promising, but some fundamental issues remain to be clarified, among which the definition of the optimal trade off between automatization and operator-dependency, the integration of these tools into clinical work flow and last not least the proof of incremental clinical benefit of these methods.

  4. Computational radiology in skeletal radiography

    Recent years have brought rapid developments in computational image analysis in musculo-skeletal radiology. Meanwhile the algorithms have reached a maturity that makes initial clinical use feasible. Applications range from joint space measurement to erosion quantification, and from fracture detection to the assessment of alignment angles. Current results of computational image analysis in radiography are very promising, but some fundamental issues remain to be clarified, among which the definition of the optimal trade off between automatization and operator-dependency, the integration of these tools into clinical work flow and last not least the proof of incremental clinical benefit of these methods.

  5. X-ray fluorescence and computed radiography analysis of a famous brazilian painting from XIX century

    Calza, Cristiane; Oliveira, Davi F.; Rocha, Henrique S.; Lopes, Ricardo Tadeu [Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Instrumentacao Nuclear], e-mail: ccalza@lin.ufrj.br; Pedreira, Andrea [Museu Nacional de Belas Artes, Rio de Janeiro, RJ (Brazil)

    2009-07-01

    This work used Energy Dispersive X-Ray Fluorescence (EDXRF) and Computed Radiography (CR) to evaluate the general conditions of the painting 'Gioventu' (Eliseu Visconti, 1898), identifying possible problems, areas that revealed signs of previous retouchings and the pigments used by the artist. EDXRF measurements were carried out with a portable system consisting of an X-ray tube Oxford TF3005 with W anode, operating at 25 kV and 100 {mu}A, and a Si-PIN XR-100CR detector from Amptek. Several spectra were obtained in each color, with an acquisition time of 300 s and a beam collimation of 2 mm. The spectra were analyzed using the software QXAS-AXIL (IAEA). The results revealed that the drawings were made over a preparatory layer of lead white. Some pigments identified were: yellow, red and brown ochre; umbra; vermilion; cobalt blue; etc. The experimental setup used in the CR analysis consisted of an Oxford X-ray source, operating at 50 kV and 200 {mu}A, placed at 85 cm from the painting, a GE CR 50P portable computed radiography scanner and a Fuji imaging plate detector. The exposure time was 600 s. The radiographic images revealed that the painting was in a good state of conservation and also a complete composition hidden underneath the visible paint layer.(author)

  6. Analysis of the painting 'Gioventu' (Eliseu Visconti) using EDXRF and computed radiography

    EDXRF and Computed Radiography were used to evaluate the general conditions of the painting 'Gioventu' (Eliseu Visconti, 1898), identifying possible problems, areas that revealed signs of previous retouchings and the pigments used by the artist. EDXRF measurements were carried out with a portable system consisting of an X-ray tube Oxford TF3005 with W anode, operating at 25 kV and 100 μA, and a Si-PIN XR100CR detector from Amptek. Several spectra were obtained in each color, with an acquisition time of 300 s and a beam collimation of 2 mm. The spectra were processed and analyzed using the software QXAS-AXIL (IAEA). The results revealed that the drawings were made over a preparatory layer of lead white. Some pigments identified were: yellow, red and brown ochre; umbra; vermilion; cobalt blue; etc. The experimental setup used in the CR analysis consisted of an Oxford X-ray source, operating at 50 kV and 200 A, placed at 85 cm from the painting, a GE CR 50P Portable Computed Radiography Scanner and a Fuji Imaging Plate detector. The exposure time was 600 s. The radiographic images revealed that the painting was in a good state of conservation

  7. X-ray fluorescence and computed radiography analysis of a famous brazilian painting from XIX century

    This work used Energy Dispersive X-Ray Fluorescence (EDXRF) and Computed Radiography (CR) to evaluate the general conditions of the painting 'Gioventu' (Eliseu Visconti, 1898), identifying possible problems, areas that revealed signs of previous retouchings and the pigments used by the artist. EDXRF measurements were carried out with a portable system consisting of an X-ray tube Oxford TF3005 with W anode, operating at 25 kV and 100 μA, and a Si-PIN XR-100CR detector from Amptek. Several spectra were obtained in each color, with an acquisition time of 300 s and a beam collimation of 2 mm. The spectra were analyzed using the software QXAS-AXIL (IAEA). The results revealed that the drawings were made over a preparatory layer of lead white. Some pigments identified were: yellow, red and brown ochre; umbra; vermilion; cobalt blue; etc. The experimental setup used in the CR analysis consisted of an Oxford X-ray source, operating at 50 kV and 200 μA, placed at 85 cm from the painting, a GE CR 50P portable computed radiography scanner and a Fuji imaging plate detector. The exposure time was 600 s. The radiographic images revealed that the painting was in a good state of conservation and also a complete composition hidden underneath the visible paint layer.(author)

  8. Comparison of film digitization and computed radiography for quantitative analysis of lung texture

    The authors are developing an automated computerized scheme to quantify interstitial diseases by using physical measure of lung textures in chest radiographs. In order to implement this scheme for practical use, the authors are investigating the effect of different digital systems on the performance of this scheme. Chest images of the same patients were obtained with conventional film and a computed radiography (CR) system. Texture measures were determined by digitization of chest radiographs with a drum scanner (0.1-mm pixel size) and laser scanner (0.175-mm pixel size), as well as from digital images with CR system (0.2mm pixel size). Receiver operating characteristic curves for detection of interstitial disease obtained with three digital system are compared together with analysis of their imaging properties

  9. Computed radiography in NDT applications

    Computed Radiography, or digital radiography by use of reusable Storage Phosphor screens, offers a convenient and reliable way to replace film. In addition to the reduced cost on consumables, the return on investment of CR systems is strongly determined by savings in exposure time, processing times and archival times. But also intangible costs like plant shutdown, environment safety and longer usability of isotopes are increasingly important when considering replacing film by Storage Phosphor systems. But more than in traditional radiography, the use of digital images is a trade-off between the speed and the required quality. Better image quality is obtained by longer exposure times, slower phosphor screens and higher scan resolutions. Therefore, different kinds of storage phosphor screens are needed in order to cover every application. Most operations have the data, associated with the tests to be performed, centrally stored in a database. Using a digital radiography system gives not only the advantages of the manipulation of digital images, but also the digital data that is associated with it. Smart methods to associate cassettes and Storage screens with exposed images enhance the workflow of the NDT processes, and avoid human error. Automated measurements tools increase the throughput in different kinds of operations. This paper gives an overview of the way certain operations have decided to replace film by Computed Radiography, and what the major benefits for them have been. (author)

  10. Computed radiography in NDT application

    Computed Radiography, or digital radiography by use of reusable Storage Phosphor screens, offers a convenient and reliable way to replace film. In addition to the reduced cost on consumables, the return on investment of CR systems is strongly determined by savings in exposure time, processing times and archival times. But also intangible costs like plant shutdown, environment safety and longer usability of isotopes are increasingly important when considering replacing film by Storage Phosphor systems. But mote than in traditional radiography, the use of digital images is a trade-off between the speed and the required quality. Better image quality is obtained by longer exposure times, slower phosphor screens and higher scan resolutions. Therefore, different kinds of storage phosphor screens are needed in order to cover every application. Most operations have the data, associated with the tests to be performed, centrally stored in a database. Using a digital radiography system gives not only the advantages of the manipulation of digital images, but also the digital data that is associated with it. Smart methods to associate cassettes and Storage screens with exposed images enhance the workflow of the NDT processes, and avoid human error. Automated measurements tools increase the throughput in different kinds of operations. This paper gives an overview of the way certain operations have decided to replace film by Computed Radiography, and what the major benefits for them have been.

  11. Analysis of edentulous maxillae using computed tomography and panoramic radiography in the surgical planning of dental implants

    Objective: to determine agreement of three observers on analysis of linear measurements of edentulous maxillae using computed tomography and panoramic radiography in the surgical planning of dental implants. Material and Method: the samples of 17 patients were analyzed with computed tomography and panoramic radiography. Linear measurements obtained from both methods were made at the following anatomical points: left tuberosity, left canine pillar, incisive foramen, right canine pillar and right tuberosity. Kendall's W test was applied to assess the level of agreement. Results: measured W-values from the samples of the anatomical points mentioned above, analyzed with panoramic radiography and computed tomography, were: 0.75 and 0.901; 0.916 and 0.956; 0.843 and 0.964; 0.963 and 0.931; 0.95 and 0.89 respectively. Statistical analysis showed that there was no statistically significant difference. Conclusion: agreement occurred in the measurements of variables.That means that if the three observers were to select an implant to be placed in each of the anatomical regions studied, there would be a good chance whey would choose the same type. (author)

  12. Acute Knee Trauma: Analysis of Multidetector Computed Tomography Findings and Comparison with Conventional Radiography

    Mustonen, A.O.T. [Helsinki Univ. Central Hospital (Finland). Dept. of Radiology; Koskinen, S.K. [Research Inst. of Military Medicine, Helsinki (Finland); Kiuru, M.J. [ORTON Orthopaedic Hospital, Helsinki (Finland)

    2005-12-01

    Purpose: To evaluate the multidetector computed tomography (MDCT) findings of acute knee trauma and to compare radiography with MDCT in patients referred ta level 1 trauma center. Material and Methods: During a 5-year period, a total of 415 MDCT examinations were performed on 409 patients with acute knee trauma to reveal complex fracture anatomy or rule out a fracture. MDCT and primary radiographs were re-evaluated with respect to fracture location and trauma mechanism. Tibial plateau fractures were further analyzed depending on anatomical location: anterior-medial, anterior-lateral, posterior-lateral, and posterior-medial regions. Maximal depression of the tibial articular surface was measured. Findings on the primary knee radiographs were compared with MDCT findings. Results: Of the 409 patients, 356 (87%) had a knee fracture. A total of 451 fractures were found in all anatomic regions: distal femur ( n = 49), proximal tibia ( n 307), patella ( n = 23), and proximal fibula ( n = 72). Primary radiographs were available in 316 (76%) cases. Of these, 225 (71%) had MDCT in order to reveal the fracture anatomy better, and 91 (29%) had a subsequent MDCT after negative plain radiographs. Overall sensitivity of radiography was 83%, while negative predictive value was 49%. On radiography, tibial plateau articular depression was underestimated in all regions except when the fracture consisted of the whole half of the anterior or posterior plateau. The three main injury mechanisms were traffic accident, a simple fall, and sport. In 49 cases (15%), primary radiographs were suboptimal due to positioning. Conclusion: In severely injured patients, diagnostically sufficient radiographs are difficult to obtain, and therefore a negative radiograph is not reliable in ruling out a fracture. In these patients, MDCT is a fast and accurate examination and is also recommended in patients with tibial plateau fractures or complex knee injuries in order to evaluate the fracture adequately.

  13. Acute Knee Trauma: Analysis of Multidetector Computed Tomography Findings and Comparison with Conventional Radiography

    Purpose: To evaluate the multidetector computed tomography (MDCT) findings of acute knee trauma and to compare radiography with MDCT in patients referred ta level 1 trauma center. Material and Methods: During a 5-year period, a total of 415 MDCT examinations were performed on 409 patients with acute knee trauma to reveal complex fracture anatomy or rule out a fracture. MDCT and primary radiographs were re-evaluated with respect to fracture location and trauma mechanism. Tibial plateau fractures were further analyzed depending on anatomical location: anterior-medial, anterior-lateral, posterior-lateral, and posterior-medial regions. Maximal depression of the tibial articular surface was measured. Findings on the primary knee radiographs were compared with MDCT findings. Results: Of the 409 patients, 356 (87%) had a knee fracture. A total of 451 fractures were found in all anatomic regions: distal femur ( n = 49), proximal tibia ( n 307), patella ( n = 23), and proximal fibula ( n = 72). Primary radiographs were available in 316 (76%) cases. Of these, 225 (71%) had MDCT in order to reveal the fracture anatomy better, and 91 (29%) had a subsequent MDCT after negative plain radiographs. Overall sensitivity of radiography was 83%, while negative predictive value was 49%. On radiography, tibial plateau articular depression was underestimated in all regions except when the fracture consisted of the whole half of the anterior or posterior plateau. The three main injury mechanisms were traffic accident, a simple fall, and sport. In 49 cases (15%), primary radiographs were suboptimal due to positioning. Conclusion: In severely injured patients, diagnostically sufficient radiographs are difficult to obtain, and therefore a negative radiograph is not reliable in ruling out a fracture. In these patients, MDCT is a fast and accurate examination and is also recommended in patients with tibial plateau fractures or complex knee injuries in order to evaluate the fracture adequately

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

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

  15. Corrosion Surveillance In Pipe By Computed Radiography

    Computed Radiography (CR) is a technique of digital industrial radiology which is developed to replace conventional radiography. With a CR system, the detection of the outer and inner wall surface of the pipe is done usually by edge detection and filter algorithms of the profile line at the position under investigation. Applying in industries, radiographic examination shall be performed in accordance with a written procedure. This paper summarizes collected knowledge and experimental results to establish a procedure for radiography applications in monitoring corrosion in small bore pipes. (author)

  16. Clinical application of computed radiography

    Observer performance tests were performed to compare the diagnostic accuracy of digitized storage phosphors and conventional radiography in the detection of microcalcification in the breast and pulmonary nodules. Clustered microcalcifications (0.125-0.177 mm, 0.210-0.250 mm) were randomly superimposed on a human breast specimen. Two types of screen-film systems (Toshiba MM6/Fuji MINC, Kodak MinR/Kodak MinR) and CR images either with unsharp mask or with no image processing (unprocess) were used as imaging systems. Nine readers assessed the capability of screen-films, and unsharp-masked and unprocessed mammograms to detect microcalcifications. Observer performance data were evaluated by receiver operating characteristics (ROC) analysis. Both the area under ROC curve and the true positive localization fraction were used as performance indexes. Two screen-film images provided a higher detectability of microcalcifications than CR images. In the detectability of microcalcifications, unsharp-masked images were superior to unprocessed images, with no statistically significant difference. CR images showed higher false positive fraction than screen-film systems. To assess the detectability of pulmonary nodules, 15 radiologists compared the diagnostic accuracy of screen-film system and CR images, including unprocessed, unsharp-masked, reversed and paired images, in 18 normal volunteers and 18 patients with pulmonary nodules. Overall diagnostic accuracy of CR images, except for reversed images, were comparable to the screen-film system. In case of definite, large nodules, unprocessed, unsharp-masked, and paired images were superior to the screen-film and reversed images. Screen-film and unprocessed images were helpful in cases of tiny nodules without definite contrast. The detectability of pulmonary nodules may be affected by image processing conditions, radiologist' experiences, and characteristics of nodules themselves. (N.K.) 59 refs

  17. Comparison of flat-panel radiography and computed radiography in urography

    Purpose: To evaluate the diagnostic value of digital flat-panel radiography in uro-radiology the i.v. urograms of patients who had been examined with computed radiography and digital flat-panel radiography were compared regarding image quality. Methods: 50 patients who underwent clinically indicated i.v. urography were examined with digital flat-panel radiography and computed radiography. In order to avoid unnecessary double exposure to X-rays, patients were examined either by flat-panel or computed radiography before injection of contrast media. Each further clinically indicated exposure after administration of contrast media was done by alternating the other examination technique. The digital images were compared by 4 radiologists regarding image quality for the detection of defined anatomic structures. Results: Digital flat-panel radiography showed an image quality of the liver, spleen and both kidneys that was similar to computed radiography. The urinary tract, lumbar spine, pelvis and psoas muscle were significantly better visible on flat-panel radiography images. Conclusions: Compared to computed radiography there is no loss of image information by using digital flat-panel radiography in uro-radiology. On the contrary, some anatomic structures on abdominal survey images show better image quality. In conclusion, digital flat-panel radiography has the potential to replace computed radiography in uroradiologic examinations. (orig.)

  18. Computed radiography- the state of the art

    Despite the advantages obtained with the radiographic inspection, the risks inherent to the exposure of ionizing radiations not always represented the major limiters regarding the employment of the technique. However, with the arrival of the computed radiography, the industrial radiology gets space again due to the benefits provided by the new technology, among which the following are outstanding: possibility of reduction of the time of radiography exposure and, consequently, of the marking area, direct acquisition of images, reduction of consumables and chemical waste and possibility of using again the detectors (imaging plates). Before such a favorable scenario, the computed radiography is being highlighted as the solution for almost all the problems, even without the full knowledge of its advantages and restrictions. This work briefly presents the state of the art related with the industrial applications (in-service inspection of wall loss and weld inspection) and the limitations noticed up to the moment are discussed. (author)

  19. Use of computed radiography for portal imaging

    This paper compares image quality of conventional film based portal images with the quality of portal images based on computed radiography (CR). The paper concludes that portal imaging with CR imaging plates instead of the conventional film provides images which have a significantly higher image quality. CR based portal images permit better visualization of important landmarks

  20. Integrating computer aided radiography and plantar pressure measurements for complex gait analysis

    Radiographic Fluoroscopy (DRF) and Contact Pressure Display (CPD). The CPD method uses a birefiingent integrated optical sandwich for contact stress analysis, e.g. plantar pressure distribution. The DRF method displays and electronically records skeletal motion using X-ray radiation, providing the exact bone and joint positions during gait. Integrating the two techniques, contribution of each segment to the HFS behavior may be studied by applying image processing and analysis techniques. The combined resulted data may be used not only to detect and diagnose gait pathologies but also as a base for development of advanced numerical models of the foot structure

  1. Pepper seed germination assessed by combined X-radiography and computer-aided imaging analysis

    A lot of pepper seeds having 87% germination were subjected to X-ray inspection using a non lethal dose of radiation. Seeds with less than 2.7% (on the basis of total seed area) of free space area, i.e. the spaces between embryo and endosperm, were classified as highly viable seeds (97-100% germination) with the lowest level of abnormal seedlings. Seeds X-ray classified as good were subjected to a computerised image analysis to study seed imbibition and radicle elongation. The patterns of seed area increase, chosen as the most accurate indicator of seed swelling, resembled the triphasic curve of water uptake. The first phase was completed at 9 h followed by a second phase that varied widely in time until completion of germination between 52 and 96 h. The proportion of seeds with radicle protrusion between 52-56 h and 64-72 h assessed with the image analysis was significantly higher than that recorded using a conventional germination test. In addition, the rate of increase of seed area during the third phase of imbibition, mostly due to protrusion of the radicle tip and its growth, was highly correlated with the corresponding radicle elongation rate

  2. Computed vs. film-screen magnification radiography of fingers in hyperparathyroidism. An ROC analysis

    One hundred randomly selected patients with suspected or known hyperparathyroidism were examined in a prospective study of the 2nd and 3rd fingers with film-screen and digital luminescence radiographs using magnification technique. The digital images were displayed on a work-station and printed as hard-copies. Two radiologists evaluated the film-screen images regarding subperiosteal and intracortical resorption and their results were defined as ''gold standard'' regarding the absence or presence of these changes. Four radiologists evaluated these changes in the 3 image forms and an ROC analysis was performed. Comparing the areas under the ROC curves to significant difference was found between the film-screen images and the 2 digital display forms. These results suggest that currently available digital systems provide adequate diagnostic accuracy for evaluation of subtle skeletal changes. (orig.)

  3. Introduction of computed radiography in two mammography services: Image quality and dose analysis

    This study has evaluated the impact of the introduction of CR technology in the routine of two mammography services operating with Lorad Affinity x-ray units and CR Fuji Profect One system. Mean glandular dose was determined to set Automatic Exposure Control parameters according to optimal image quality. Reject analysis of patient images was made to establish the overall impact in routine work. As regards to dose evaluation, the results show that in 44% of mammography exams the MGD were above action levels. It is due to inadequate AEC adjustment and insufficient training of the staff in operating CR systems. In addition, common errors with screen/film systems like wrong breast positing and selection of exposure parameters, as well as x-ray unit failures like insufficient anti scatter grid movement still occurs. This is an indication that ongoing efforts should be concentrated in the constancy of AEC adjustment for CR image plates and staff training. Until now, brazilian health authorities did not implement any program to evaluate digital systems performance, but efforts are being done in order to provide guidelines to breast screening aiming the control of breast dose compatible with optimal image quality. (author)

  4. Introduction of computed radiography in two mammography services: image quality and dose analysis

    This study has evaluated the impact of the introduction of CR technology in the routine of two mammography services operating with Lorad Affinity X-ray units and CR Fuji Profect One system. Mean glandular dose was determined to set Automatic Exposure Control parameters according to optimal image quality. Reject analysis of patient images was made to establish the overall impact in routine work. As regards to dose evaluation, the results show that in 44% of mammography exams the MGD were above action levels. It is due to inadequate AEC adjustment and insufficient training of the staff in operating CR systems. In addition, common errors with screen/film systems like wrong breast positing and selection of exposure parameters, as well as X-ray unit failures like insufficient anti scatter grid movement still occurs. This is an indication that ongoing efforts should be concentrated in the constancy of AEC adjustment for CR image plates and staff training. Until now, brazilian health authorities did not implement any program to evaluate digital systems performance, but efforts are being done in order to provide guidelines to breast screening aiming the control of breast dose compatible with optimal image quality. (author)

  5. Optimization and quality control of computed radiography

    Willis, Charles E.; Weiser, John C.; Leckie, Robert G.; Romlein, John R.; Norton, Gary S.

    1994-05-01

    Computed radiography (CR) is a relatively new technique for projection radiography. Few hospitals have CR devices in routine service and only a handful have more than one CR unit. As such, the clinical knowledge base does not yet exist to establish quality control (QC) procedures for CR devices. Without assurance that CR systems are operating within nominal limits, efforts to optimize CR performance are limited in value. A complete CR system includes detector plates that vary in response, cassettes, an electro-optical system for developing the image, computer algorithms for processing the raw image, and a hard copy output device. All of these subsystems are subject to variations in performance that can degrade image quality. Using CR manufacturer documentation, we have defined acceptance protocols for two different Fuji CR devices, the FCR 7000 and the AC1+, and have applied these tests to ten individual machines. We have begun to establish baseline performance measures and to determine measurement frequencies. CR QC is only one component of the overall quality control for totally digital radiology departments.

  6. Computed radiography simulation using the Monte Carlo code MCNPX

    Simulating x-ray images has been of great interest in recent years as it makes possible an analysis of how x-ray images are affected owing to relevant operating parameters. In this paper, a procedure for simulating computed radiographic images using the Monte Carlo code MCNPX is proposed. The sensitivity curve of the BaFBr image plate detector as well as the characteristic noise of a 16-bit computed radiography system were considered during the methodology's development. The results obtained confirm that the proposed procedure for simulating computed radiographic images is satisfactory, as it allows obtaining results comparable with experimental data. (author)

  7. The art of rejection: Comparative analysis between Computed Radiography (CR) and Digital Radiography (DR) workstations in the Accident & Emergency and General radiology departments at a district general hospital using customised and standardised reject criteria over a three year period

    Aims: Reject analysis continues to play an integral part of a Quality Assurance (QA) program. This study aims to show how Computed Radiography (CR) and Digital Radiography (DR) reject analysis data can be customised by the user to aid in the interpretation of exported data and identify trends and issues relating to technique and training. Materials and methods: Reject analysis was reviewed for the period of 2011–2014 using exported data from CR and DR systems in the Accident and Emergency (A&E) and General radiology departments at a district general hospital. Reject criteria was customised to departmental needs and standardised across all workstation's with monthly data collection for amalgamation onto a central spreadsheet. Results: Analysis by workstation and department was performed with regards to total number of exposure events, rejects and reject ratios (%) and reasons for film rejection (positional and exposure) were reviewed. Annual overall reject ratios (%) were shown to be on average within levels acceptable by the World Health Organisation (WHO)1 with some variability on monthly basis according to workloads experienced. Conclusions: A number of improvements have been suggested to improve data reliability for future analysis and the continuation of a review of the physical rejected image is recommended as this can highlight problematic areas and help to reveal trends which pure data cannot show. - Highlights: • Retrospective analysis of three years CR/DR rejects using customised QA program. • Reviewed data by individual workstations and departments. • Highlighted trends between workstations and departments. • Overall annual reject rates shown to be within WHO recommendations. • Recommendations for future improvements for reject analysis within department and continued review of JPEG images

  8. Radiological protection procedures for industrial applications of computed radiography

    Due to its very particular characteristics, industrial radiography is responsible for roughly half of the relevant accidents in nuclear industry, in developed as well as in developing countries, according to the International Atomic Energy Agency (IAEA). Thus, safety and radiological protection in industrial gamma radiography have been receiving especial treatment by regulatory authorities of most Member States. The main objective of the present work was to evaluate, from the radioprotection point of view, the main advantages of computed radiography (CR) for filmless industrial radiography. In order to accomplish this, both techniques, i.e. conventional and filmless computed radiography were evaluated and compared through practical studies. After the studies performed at the present work it was concluded that computed radiography significantly reduces the inherent doses, reflecting in smaller restricted areas and costs, with consequent improvement in radiological protection and safety. (author)

  9. Multidimensional analysis in industrial radiography

    EDF uses non-destructive testing by X or gamma-ray radiography for routine nozzle inspection in nuclear power plants. The images obtained are examined by radiographic specialists in order to detect, identify and quantify any defects, but the quality of the radiograms and the small size of the defects make their work extremely difficult. It is for these reasons that EDF developed ENTRAIGUES, a digital package for the processing and aid in interpretation of images generated by radiographical inspections, aimed at: -digitizing the radiographic films to be appraised, - facilitating analysis of the digitized radiograms. Defect orientation is estimated by 3D reconstruction of the component being inspected, based on a limited number of its projections. (authors). 11 figs., 6 refs

  10. Computed radiography imaging plates and associated methods of manufacture

    Henry, Nathaniel F.; Moses, Alex K.

    2015-08-18

    Computed radiography imaging plates incorporating an intensifying material that is coupled to or intermixed with the phosphor layer, allowing electrons and/or low energy x-rays to impart their energy on the phosphor layer, while decreasing internal scattering and increasing resolution. The radiation needed to perform radiography can also be reduced as a result.

  11. Computer radiography-X-ray with vision

    Computer radiography describes an entire process of creating a digital image including acquiring, processing, presenting and managing the image data. the cassettes are special in that they use an imaging plate instead of films. the imaging plate is coated with storage phosphors which captures x-ray as they pass through the patient. the imaging plate is read with a bar code reader and the imaging plate number recorded in the computer. The cassette is then loaded in the reader unit where it is read using infra-red light which excites the particles on the plate which in turn illuminates and picked by photo-sensors which converts the signal into digital pulses. the pulses then run through a board which converts it into an image which is then displayed on the control console. The plate then runs through the erasure section where it is exposed to yellow light, which erases the plate. The IP is then put back in the cassette and locked and can be reused for the next episode

  12. Analysis on imaging features of mammography in computer radiography and investigation on gray scale transform and energy subtraction

    In this dissertation, a novel transform method based on human visual response features for gray scale mammographic imaging in computer radiography (CR) is presented. The parameters for imaging quality on CR imaging for mammography were investigated experimentally. In addition, methods for image energy subtraction and a novel method of image registration for mammography of CR imaging are presented. Because the images are viewed and investigated by humans, the method of displaying differences in gray scale images is more convenient if the gray scale differences are displayed in a manner commensurate with human visual response principles. Through transformation of image gray scale with this method, the contrast of the image will be enhanced and the capability for humans to extract the useful information from the image will be increased. Tumors and microcalcifications are displayed in a form for humans to view more simply after transforming the image. The method is theoretically and experimentally investigated. Through measurement of the parameters of a geometrically blurred image, MTF, DQE, and ROC on CR imaging, and also comparison with the imaging quality of screen-film systems, the results indicate that CR imaging qualities in DQE and ROC are better than those of screen-film systems. In geometric blur of the image and MTF, the differences in image quality between CR and the screen-film system are very small. The results suggest that the CR system can replace the screen-film system for mammography imaging. In addition, the results show that the optimal imaging energy for CR mammography is about 24 kV. This condition indicates that the imaging energy of the CR system is lower than that of the screen-film system and, therefore, the x-ray dose to the patient for mammography with the CR system is lower than that with the screen-film system. Based on the difference of penetrability of x ray with different wavelength, and the fact that the part of the x-ray beam will pass

  13. Evaluation and testing of computed radiography systems

    The implementation of film replacement digital radiographic imaging systems throughout Europe is now gathering momentum. Such systems create the foundations for totally digital departments of radiology, since radiographic examinations constitute the most prevalent modality. Although this type of development will lead to improvements in the delivery and management of radiological service, such widespread implementation of new technology must be carefully monitored. The implementation of effective QA tests on installation, at periodic intervals and as part of a routine programme will aid this process. This paper presents the results of commissioning tests undertaken on a number of computed radiography imaging systems provided by different manufacturers. The aim of these tests was not only to provide baseline performance measurements against which subsequent measurements can be compared but also to explore any differences in performance, which might exist between different units. Results of measurements will be presented for (1) monitor and laser printer setup; (2) imaging plates, including sensitivity, consistency and uniformity; (3) resolution and contrast detectability; and (4) signal and noise performance. Results from the latter are analysed in relationship with both system and quantum noise components. (authors)

  14. Evaluation and testing of computed radiography systems.

    Charnock, P; Connolly, P A; Hughes, D; Moores, B M

    2005-01-01

    The implementation of film replacement digital radiographic imaging systems throughout Europe is now gathering momentum. Such systems create the foundations for totally digital departments of radiology, since radiographic examinations constitute the most prevalent modality. Although this type of development will lead to improvements in the delivery and management of radiological service, such widespread implementation of new technology must be carefully monitored. The implementation of effective QA tests on installation, at periodic intervals and as part of a routine programme will aid this process. This paper presents the results of commissioning tests undertaken on a number of computed radiography imaging systems provided by different manufacturers. The aim of these tests was not only to provide baseline performance measurements against which subsequent measurements can be compared but also to explore any differences in performance, which might exist between different units. Results of measurements will be presented for (1) monitor and laser printer set-up; (2) imaging plates, including sensitivity, consistency and uniformity; (3) resolution and contrast detectability; and (4) signal and noise performance. Results from the latter are analysed in relationship with both system and quantum noise components. PMID:15933109

  15. Performance evaluation of computed radiography systems

    Recommended methods to test the performance of computed radiography (CR) digital radiographic systems have been recently developed by the AAPM Task Group No. 10. Included are tests for dark noise, uniformity, exposure response, laser beam function, spatial resolution, low-contrast resolution, spatial accuracy, erasure thoroughness, and throughput. The recommendations may be used for acceptance testing of new CR devices as well as routine performance evaluation checks of devices in clinical use. The purpose of this short communication is to provide a tabular summary of the tests recommended by the AAPM Task Group, delineate the technical aspects of the tests, suggest quantitative measures of the performance results, and recommend uniform quantitative criteria for the satisfactory performance of CR devices. The applicability of the acceptance criteria is verified by tests performed on CR systems in clinical use at five different institutions. This paper further clarifies the recommendations with respect to the beam filtration to be used for exposure calibration of the system, and the calibration of automatic exposure control systems

  16. Image analysis in industrial radiography

    Non-destructive testing in nuclear power plants remains a major EDF objective for the coming decades. To facilitate diagnosis, the expert must be provided with elaborate decision-making aids: contrasted images, noise-free signals, pertinent parameters, ''meaningful'' images. In the field of industrial radiography, the inspector's offer of a portable system for digitalization and subsequent processing of radiographs (ENTRAIGUES) is an improvement in the inspection of primary circuit nozzles. Three major directions were followed: - improvement of images and localization of flaws (2D approach); techniques such as Markov modelling were evaluated and tested, - development of a system which can be transported on site, for digitalization, processing and subsequent archiving on inspection radiographs, known as ENTRAIGUES, - development of a program for aid in analysis of digitized radiographs (''bread-board'' version), offering an ergonomic interface and push-button processing, which is the software component in ENTRAIGUES and uses sophisticated methods: contrast enhancement, background flattening, segmentation. An other objective is to reconstruct a three-dimensional volume on the basis of a few radiographs taken at different incidences and to estimate the flaw orientation within a piece understudy. This information makes sense to experts, with regards to the deterioration rate of the flaw; the equipment concerned includes the formed bends in the primary coolant nozzles. This reconstruction problem is ill-posed and a solution can be obtained by introducing a priori information on the solution. The first step of our algorithm is a classical iterative reconstruction A.R.T. type method (Algebraic Reconstruction Techniques) which provides a rough volumic reconstructed tridimensional zone containing the flaw. Then, on this reconstructed zone, we apply a Bayesian restoration method introducing a Markov Random Field (MRF) modelling. Conclusive results have been obtained. (author

  17. Extremity exams optimization for computed radiography

    The computed radiography (CR) has become the most used device for image acquisition, since its introduction in the 80s. The detection and early diagnosis, obtained through CR examinations, are important for the successful treatment of diseases of the hand. However, the norms used for optimization of these images are based on international protocols. Therefore, it is necessary to determine letters of radiographic techniques for CR system, which provides a safe medical diagnosis, with doses as low as reasonably achievable. The objective of this work is to develop an extremity homogeneous phantom to be used in the calibration process of radiographic techniques. In the construction process of the simulator, it has been developed a tissues' algorithm quantifier using Matlab®. In this process the average thickness was quantified from bone and soft tissues in the region of the hand of an anthropomorphic simulator as well as the simulators' material thickness corresponding (aluminum and Lucite) using technique of mask application and removal Gaussian histogram corresponding to tissues of interest. The homogeneous phantom was used to calibrate the x-ray beam. The techniques were implemented in a calibrated hand anthropomorphic phantom. The images were evaluated by specialists in radiology by the method of VGA. Skin entrance surface doses were estimated (SED) corresponding to each technique obtained with their respective tube charge. The thicknesses of simulators materials that constitute the homogeneous phantom determined in this study were 19.01 mm of acrylic and 0.81 mm of aluminum. A better picture quality with doses as low as reasonably achievable decreased dose and tube charge around 53.35% and 37.78% respectively, compared normally used by radiology diagnostic routine clinical of HCFMB-UNESP. (author)

  18. Chest X ray effective doses estimation in computed radiography

    Conventional chest radiography is technically difficult because of wide in tissue attenuations in the chest and limitations of screen-film systems. Computed radiography (CR) offers a different approach utilizing a photostimulable phosphor. photostimulable phosphors overcome some image quality limitations of chest imaging. The objective of this study was to estimate the effective dose in computed radiography at three hospitals in Khartoum. This study has been conducted in radiography departments in three centres Advanced Diagnostic Center, Nilain Diagnostic Center, Modern Diagnostic Center. The entrance surface dose (ESD) measurement was conducted for quality control of x-ray machines and survey of operators experimental techniques. The ESDs were measured by UNFORS dosimeter and mathematical equations to estimate patient doses during chest X rays. A total of 120 patients were examined in three centres, among them 62 were males and 58 were females. The overall mean and range of patient dosed was 0.073±0.037 (0.014-0.16) mGy per procedure while the effective dose was 3.4±01.7 (0.6-7.0) mSv per procedure. This study compared radiation doses to patients radiographic examinations of chest using computed radiology. The radiation dose was measured in three centres in Khartoum- Sudan. The results of the measured effective dose showed that the dose in chest radiography was lower in computed radiography compared to previous studies.(Author)

  19. A methodology for radiological accidents analysis in industrial gamma radiography

    A critical review of 34 published severe radiological accidents in industrial gamma radiography, that happened in 15 countries, from 1960 to 1988, was performed. The most frequent causes, consequences and dose estimation methods were analysed, aiming to stablish better procedures of radiation safety and accidents analysis. The objective of this work is to elaborate a radiological accidents analysis methodology in industrial gamma radiography. The suggested methodology will enable professionals to determine the true causes of the event and to estimate the dose with a good certainty. The technical analytical tree, recommended by International Atomic Energy Agency to perform radiation protection and nuclear safety programs, was adopted in the elaboration of the suggested methodology. The viability of the use of the Electron Gamma Shower 4 Computer Code System to calculate the absorbed dose in radiological accidents in industrial gamma radiography, mainly at sup(192)Ir radioactive source handling situations was also studied. (author)

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

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

  1. Noise analysis of a digital radiography system

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

  2. Collaboration in radiography: A bibliometric analysis

    Introduction: Increasing research activity is an aim of the radiography profession, but there is a lack of knowledge of how this can be achieved. Collaboration between clinical and academic centres as well as between individuals has increased productivity in other professions and has been suggested as a strategy for radiography. This bibliometric study maps the current contribution to the radiography evidence base through a single journal. Method: All articles published in Radiography from 1997 to 2011 were reviewed to identify collaboration trends together with article type and subject. Analysis also enabled comparison of research and publication patterns. Results: 706 articles were published by 1205 individual authors. 63.0% were written by UK based authors, although this varied over time. Over 80% of authors published only single article. Two thirds of articles were collaborative with an increase in clinical-academic co-authorship over the 15 years of the study. Although the majority of articles were diagnostic imaging based, the pattern mirrors the UK workforce profile. Clinicians, including clinical-academic co-authors, tend to write about clinical practice and roles, whereas academics write about a broader range of topics. Conclusions: There has been a growth in research and scholarship within the UK radiography journal and both clinical and academic radiographers are contributing to the evidence base through increased collaboration.

  3. Single-exposure dual-energy computed radiography.

    Stewart, B K; Huang, H K

    1990-01-01

    This paper focuses on analysis and development of a single-exposure dual-energy digital radiographic method using computed radiography (Fuji FCR-101 storage phosphor system). A detector sandwich consisting of storage phosphor imaging plates and an interdetector filter is used. The goal of this process is to provide a simple dual-energy method using typical plane-projection radiographic equipment and techniques. This approach exploits the transparency of the storage phosphor plates, using radiographic information that would be otherwise lost, to provide energy selective information essentially as a by-product of the radiographic examination. In order to effectively make use of the large dynamic range of the storage phosphor imaging plates (10,000:1), a computed radiography image reading mode of fixed analog-to-digital converter gain and variable photomultiplier sensitivity provides image data which can be related to relative incident exposure for export to the decomposition algorithm. Scatter rejection requirements necessitated crossed 12:1 grids for a field size of 36 x 36 cm. Optimal technique parameters obtained from computer simulation through minimization of the aluminum and Plexiglas equivalent image uncertainty under conditions of constant absorbed does resulted as: 100 kVp using a 0.15-mm-thick tin (Sn) interdetector filter for the lung field. This yields a surface exposure of 23 mR and a surface absorbed dose of 0.26 mGy for a 23-cm-thick chest. Clinical application in evaluation of the solitary pulmonary nodule is discussed, along with an image set demonstrating this application. PMID:2233574

  4. Artifacts Found During Quality Assurance Testing of Computed Radiography and Digital Radiography Detectors

    Honey, Ian D.; MacKenzie, Alistair

    2008-01-01

    A series of artifact images, obtained over 5 years of performance testing, of both computed radiography (CR) and integrated digital radiographic X-ray imaging detectors are presented. The images presented are all either flat field or test object images and show artifacts previously either undescribed in the existing literature or meriting further comment. The artifacts described are caused by incorrect flat field corrections, a failing amplifier, damaged detector lines affecting their neighbo...

  5. Analysis of edentulous maxillae using computed tomography and panoramic radiography in the surgical planning of dental implants; Analise da maxila edentula por meio da tomografia computadorizada e radiografia panoramica no planejamento cirurgico de implantes dentarios

    Sahuinco, Humberto Lazaro Choquepuma; Souza, Ricardo Pires de [Complexo Hospitalar Heliopolis (HOSPHEL), Sao Paulo, SP (Brazil). Curso de pos-graduacao em Ciencias da Saude]. E-mail: humbertchs@hotmail.com

    2006-04-15

    Objective: to determine agreement of three observers on analysis of linear measurements of edentulous maxillae using computed tomography and panoramic radiography in the surgical planning of dental implants. Material and Method: the samples of 17 patients were analyzed with computed tomography and panoramic radiography. Linear measurements obtained from both methods were made at the following anatomical points: left tuberosity, left canine pillar, incisive foramen, right canine pillar and right tuberosity. Kendall's W test was applied to assess the level of agreement. Results: measured W-values from the samples of the anatomical points mentioned above, analyzed with panoramic radiography and computed tomography, were: 0.75 and 0.901; 0.916 and 0.956; 0.843 and 0.964; 0.963 and 0.931; 0.95 and 0.89 respectively. Statistical analysis showed that there was no statistically significant difference. Conclusion: agreement occurred in the measurements of variables.That means that if the three observers were to select an implant to be placed in each of the anatomical regions studied, there would be a good chance whey would choose the same type. (author)

  6. Computer-aided recognition of emphysema on digital chest radiography.

    Miniati, Massimo; Coppini, Giuseppe; Monti, Simonetta; Bottai, Matteo; Paterni, Marco; Ferdeghini, Ezio Maria

    2011-01-01

    Background Computed tomography (CT) is the benchmark for diagnosis emphysema, but is costly and imparts a substantial radiation burden to the patient. Objective To develop a computer-aided procedure that allows recognition of emphysema on digital chest radiography by using simple descriptors of the lung shape. The procedure was tested against CT. Methods Patients (N=225), who had undergone postero-anterior and lateral digital chest radiographs and CT for diagnostic purposes, were studied and ...

  7. Control dose in chest radiography after the installation of the computed radiography

    The aim of this work is to verify patient does after the installation of the computed radiography. Entrance surface doses were obtained from a measurement of the output of the x-ray tube and exposure factor used at posteroanterior (PA) and lateral (LAT) chest in 50 adult patients before and after the installation. The obtained average values were 0.28±0.10mGy in the PA view and 0.8±0.5 mGy in the LAT view with the conventional screen-film system 0.27±0.06 mGy in PA view and 0.69±0.18 mGy in LAT view with the digital radiography system. The results do not exceed the diagnostic reference levels (DRLs) and are constant after the change of system. (Author)

  8. Computed radiography dose optimization in pediatric patients

    Radiation dose reduction in pediatric X-ray imaging is especially important because of children radiation sensitivity. For any radiographic examination performed at a fixed radiographic tube potential, the patient absorbed dose is directly proportional to the value of milliampere-seconds (mAs) selected by the operator. Nevertheless, reducing X-ray exposure has the unavoidable disadvantage of increasing the quantum noise in the resultant image. The objective of this work is to identify the minimum tube current setting required for maintaining accurate examinations, to modify, if required, the daily protocols applied at La Fe de Valencia University Hospital. To accomplish this goal, a noise addition software has been developed in order to study the diagnostic accuracy as a function of reducing dose by artificially increasing the image noise. The noise addition tool has been applied to several thorax images acquired from pediatric unit to simulate new lower dose radiographies and allow medical researchers to study how lower dose affects the patient pneumonia diagnosis. (author)

  9. Computed radiography dose optimization in pediatric patients

    Radiation dose reduction in pediatric X-ray imaging is especially important because of children radiation sensitivity. For any radiographic examination performed at a fixed radiographic tube potential, the patient absorbed dose is directly proportional to the value of milliampere-seconds (mAs) selected by the operator. Nevertheless, reducing X-ray exposure has the unavoidable disadvantage of increasing the quantum noise in the resultant image. The objective of this work is to identify the minimum tube current setting required for maintaining accurate examinations, to modify, if required, the daily protocols applied at La Fe de Valencia Universitary Hospital. To accomplish this goal, a noise addition software has been developed in order to study the diagnostic accuracy as a function of reducing dose by artificially increasing the image noise. The noise addition tool has been applied to several thorax images acquired from pediatric unit to simulate new lower dose radiographies and allow medical researchers to study how lower dose affects the patient pneumonia diagnosis. (author)

  10. Physical image quality of computed radiography in mammography system

    Full-text: Mammography is a screening procedure that mostly used for early detection of breast cancer. In digital imaging system, Computed Radiography is a cost-effective technology that applied indirect conversion detector. The paper presents physical image quality parameter measurements namely modulation transfer function (MTF), normalized noise power spectrum (NNPS) and detective quantum efficiency (DQE) of Computed Radiography in mammography system. MTF was calculated from two different orientations of slanted images of an edge test device and NNPS was estimated using flat-field image. Both images were acquired using a standard mammography beam quality. DQE was determined by applying the MTF and NNPS values into our developed software program. Both orientations have similar DQE characteristics. (author)

  11. Impeller Metrology for Pipeline Compressors Using Computed Radiography

    A new, quantitative method is described to measure features in pipeline impellers using computed radiography (CR). This capability, with an accuracy approaching 5 mils, is required to optimize the impeller design for high efficiency. The large area coverage, simplicity, and high spatial resolution of CR are ideal for this application. A novel phantom and image processing algorithm chain was used to demonstrate measurement repeatability of 99.9% (1 mil) using CR

  12. Computer-aided recognition of emphysema on digital chest radiography

    Background: Computed tomography (CT) is the benchmark for diagnosis emphysema, but is costly and imparts a substantial radiation burden to the patient. Objective: To develop a computer-aided procedure that allows recognition of emphysema on digital chest radiography by using simple descriptors of the lung shape. The procedure was tested against CT. Methods: Patients (N = 225), who had undergone postero-anterior and lateral digital chest radiographs and CT for diagnostic purposes, were studied and divided in a derivation (N = 118) and in a validation sample (N = 107). CT images were scored for emphysema using the picture-grading method. Simple descriptors that measure the bending characteristics of the lung profile on chest radiography were automatically extracted from the derivation sample, and applied to train a neural network to assign a probability of emphysema between 0 and 1. The diagnostic performance of the procedure was described by the area under the receiver operating characteristic curve (AUC). Results: AUC was 0.985 (95% confidence interval, 0.965-0.998) in the derivation sample, and 0.975 (95% confidence interval, 0.936-0.998) in the validation sample. At a probability cutpoint of 0.55, the procedure yielded 92% sensitivity and 96% specificity in the derivation sample; 90% sensitivity and 97% specificity in the validation sample. False negatives on chest radiography had trace or mild emphysema on CT. Conclusions: The computer-aided procedure is simple and inexpensive, and permits quick recognition of emphysema on digital chest radiographs.

  13. Computer-aided recognition of emphysema on digital chest radiography

    Miniati, Massimo, E-mail: Massimo.Miniati@unifi.it [Department of Medical and Surgical Critical Care, University of Florence, 50134 Florence (Italy); Coppini, Giuseppe; Monti, Simonetta [Institute of Clinical Physiology, National Research Council, 56124 Pisa (Italy); Bottai, Matteo [Unit of Biostatistics, Institute of Environmental Medicine, Karolinska Institutet, 17177 Stockholm (Sweden); Division of Biostatistics, Arnold School of Public Health, University of South Carolina, 29208 Columbia, SC (United States); Paterni, Marco; Ferdeghini, Ezio Maria [Institute of Clinical Physiology, National Research Council, 56124 Pisa (Italy)

    2011-11-15

    Background: Computed tomography (CT) is the benchmark for diagnosis emphysema, but is costly and imparts a substantial radiation burden to the patient. Objective: To develop a computer-aided procedure that allows recognition of emphysema on digital chest radiography by using simple descriptors of the lung shape. The procedure was tested against CT. Methods: Patients (N = 225), who had undergone postero-anterior and lateral digital chest radiographs and CT for diagnostic purposes, were studied and divided in a derivation (N = 118) and in a validation sample (N = 107). CT images were scored for emphysema using the picture-grading method. Simple descriptors that measure the bending characteristics of the lung profile on chest radiography were automatically extracted from the derivation sample, and applied to train a neural network to assign a probability of emphysema between 0 and 1. The diagnostic performance of the procedure was described by the area under the receiver operating characteristic curve (AUC). Results: AUC was 0.985 (95% confidence interval, 0.965-0.998) in the derivation sample, and 0.975 (95% confidence interval, 0.936-0.998) in the validation sample. At a probability cutpoint of 0.55, the procedure yielded 92% sensitivity and 96% specificity in the derivation sample; 90% sensitivity and 97% specificity in the validation sample. False negatives on chest radiography had trace or mild emphysema on CT. Conclusions: The computer-aided procedure is simple and inexpensive, and permits quick recognition of emphysema on digital chest radiographs.

  14. AEC set-up optimisation with computed radiography imaging.

    Mazzocchi, S; Belli, G; Busoni, S; Gori, C; Menchi, I; Salucci, P; Taddeucci, A; Zatelli, G

    2005-01-01

    Phototimer set-up is a critical procedure for dose and image quality optimisation in computed radiography (CR) systems. While a conventional radiography automatic exposure control device (AEC) can be calibrated in order to gain a constant optical density on the film independent of beam quality and patient size, CR detectors present a high dynamic range which allows a much larger dose interval, but with different image quality levels. CR leads to a less frequent exam repetition, but may produce quite noisy images if the exposure level on the plate is not correct. The aim of this work is to evaluate the performance of a CR plate (Agfa MD40) in order to optimally calibrate an AEC device. The plate response has been characterised in terms of digital signal, exposure on the plate and signal-to-noise ratio for different beam qualities, in a patient of standard size. PMID:16461503

  15. Computer-aided diagnosis in chest radiography: Beyond nodules

    Ginneken, Bram van [University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands)], E-mail: bram@isi.uu.nl; Hogeweg, Laurens; Prokop, Mathias [University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands)

    2009-11-15

    Chest radiographs are the most common exam in radiology. They are essential for the management of various diseases associated with high mortality and morbidity and display a wide range of findings, many of them subtle. In this survey we identify a number of areas beyond pulmonary nodules that could benefit from computer-aided detection and diagnosis (CAD) in chest radiography. These include interstitial infiltrates, catheter tip detection, size measurements, detection of pneumothorax and detection and quantification of emphysema. Recent work in these areas is surveyed, but we conclude that the amount of research devoted to these topics is modest. Reasons for the slow pace of CAD development in chest radiography beyond nodules are discussed.

  16. Development of computer assisted learning program using cone beam projection for head radiography

    We present a computer assisted learning (CAL) program to simulate head radiography. The program provides cone beam projections of a target volume, simulating three-dimensional computed tomography (CT) of a head phantom. The generated image is 512 x 512 x 512 pixels with each pixel 0.6 mm on a side. The imaging geometry, such as X-ray tube orientation and phantom orientation, can be varied. The graphical user interface (GUI) of the CAL program allows the study of the effects of varying the imaging geometry; each simulated projection image is shown quickly in an adjoining window. Simulated images with an assigned geometry were compared with the image obtained using the standard geometry in clinical use. The accuracy of the simulated image was verified through comparison with the image acquired using radiography of the head phantom, subsequently processed with a computed radiography system (CR image). Based on correlation coefficient analysis and visual assessment, it was concluded that the CAL program can satisfactorily simulate the CR image. Therefore, it should be useful for the training of head radiography. (author)

  17. Radiation Exposure in the NICU: Computed Radiography versus Digital Detector Radiography.

    Oberle, Renee

    2015-01-01

    Medical radiation exposure to pediatric patients has gained national attention in the last few years. New guidelines encourage technologists, managers, radiologists, and equipment manufacturers to tailor imaging to smaller sized patients. With the advent of computed radiography, patient radiation doses have doubled. This literature review addresses how cumulative doses received by highly radiosensitive infants in neonatal intensive care units correspond to similar doses received by infants that later developed radiation induced cancers. While technologist expertise is important for dose management with any receptor technology, converting to digital flat panel detectors can reduce dose to these areas by > 50%, and minimize risks for radiation induced cancers that often do not present until several decades after exposure. PMID:26710555

  18. High resolution digital radiography and three-dimensional computed tomography

    The predominant method used for radiographic inspection of aerospace hardware is film radiography, which is costly and time consuming. Each inspection requires many films to obtain successful viewing geometries under various x-ray conditions. Film radiography is also labor intensive, since the operator must place the film, expose it, remove it, and develop it before the images can be viewed or interpreted. In complex film inspections, it may not be possible to optimize the inspection because of the short periods allotted for nondestructive inspection (NDI). Storage and retrieval of the x-ray film is also rather cumbersome and labor intensive. Finally, film radiographs must be digitized and processed to extract quantitative information. Real-time radiographic (RTR) and near-real-time radiographic imaging systems offer solutions to some of the problems of film radiography. First, the operator can view the image immediately upon acquisition and thus optimize the inspection in a timely manner, and second, because the images are acquired electronically, the need for developing images is eliminated, and image analysis, storage, and retrieval are simplified. In this paper, the authors describe new solid-state x-ray camera system designs, the new scintillating glass and fiber-optic x-ray-to-light conversion screens, and their performance in x-ray tests. They compare the performance of these systems with that of x-ray image-intensifier tube systems and discuss the use of these new systems for acquisition of 3-D CT images

  19. Simplified techniques of cerebral angiography using a mobile X-ray unit and computed radiography

    Simplified techniques of cerebral angiography using a mobile X-ray unit and computed radiography (CR) are discussed. Computed radiography is a digital radiography system in which an imaging plate is used as an X-ray detector and a final image is displayed on the film. In the angiograms performed with CR, the spatial frequency components can be enhanced for the easy analysis of fine blood vessels. Computed radiography has an automatic sensitivity and a latitude-setting mechanism, thus serving as an 'automatic camera.' This mechanism is useful for radiography with a mobile X-ray unit in hospital wards, intensive care units, or operating rooms where the appropriate setting of exposure conditions is difficult. We applied this mechanism to direct percutaneous carotid angiography and intravenous digital subtraction angiography with a mobile X-ray unit. Direct percutaneous carotid angiography using CR and a mobile X-ray unit were taken after the manual injection of a small amount of a contrast material through a fine needle. We performed direct percutaneous carotid angiography with this method 68 times on 25 cases from August 1986 to December 1987. Of the 68 angiograms, 61 were evaluated as good, compared with conventional angiography. Though the remaining seven were evaluated as poor, they were still diagnostically effective. This method is found useful for carotid angiography in emergency rooms, intensive care units, or operating rooms. Cerebral venography using CR and a mobile X-ray unit was done after the manual injection of a contrast material through the bilateral cubital veins. The cerebral venous system could be visualized from 16 to 24 seconds after the beginning of the injection of the contrast material. We performed cerebral venography with this method 14 times on six cases. These venograms were better than conventional angiograms in all cases. This method may be useful in managing patients suffering from cerebral venous thrombosis. (J.P.N.)

  20. Tomosynthesis for the early detection of pulmonary emphysema: diagnostic performance compared with chest radiography, using multidetector computed tomography as reference

    Yamada, Yoshitake [Keio University School of Medicine, Department of Diagnostic Radiology, Tokyo (Japan); Nippon Koukan Hospital, Department of Radiology, Kawasaki-shi, Kanagawa (Japan); Jinzaki, Masahiro; Hashimoto, Masahiro; Shiomi, Eisuke; Kuribayashi, Sachio [Keio University School of Medicine, Department of Diagnostic Radiology, Tokyo (Japan); Abe, Takayuki [Keio University School of Medicine, Center for Clinical Research, Tokyo (Japan); Ogawa, Kenji [Nippon Koukan Hospital, Department of Radiology, Kawasaki-shi, Kanagawa (Japan)

    2013-08-15

    To compare the diagnostic performance of tomosynthesis with that of chest radiography for the detection of pulmonary emphysema, using multidetector computed tomography (MDCT) as reference. Forty-eight patients with and 63 without pulmonary emphysema underwent chest MDCT, tomosynthesis and radiography on the same day. Two blinded radiologists independently evaluated the tomosynthesis images and radiographs for the presence of pulmonary emphysema. Axial and coronal MDCT images served as the reference standard and the percentage lung volume with attenuation values of -950 HU or lower (LAA{sub -950}) was evaluated to determine the extent of emphysema. Receiver-operating characteristic (ROC) analysis and generalised estimating equations model were used. ROC analysis revealed significantly better performance (P < 0.0001) of tomosynthesis than radiography for the detection of pulmonary emphysema. The average sensitivity, specificity, positive predictive value and negative predictive value of tomosynthesis were 0.875, 0.968, 0.955 and 0.910, respectively, whereas the values for radiography were 0.479, 0.913, 0.815 and 0.697, respectively. For both tomosynthesis and radiography, the sensitivity increased with increasing LAA{sub -950}. The diagnostic performance of tomosynthesis was significantly superior to that of radiography for the detection of pulmonary emphysema. In both tomosynthesis and radiography, the sensitivity was affected by the LAA{sub -950}. (orig.)

  1. Tomosynthesis for the early detection of pulmonary emphysema: diagnostic performance compared with chest radiography, using multidetector computed tomography as reference

    To compare the diagnostic performance of tomosynthesis with that of chest radiography for the detection of pulmonary emphysema, using multidetector computed tomography (MDCT) as reference. Forty-eight patients with and 63 without pulmonary emphysema underwent chest MDCT, tomosynthesis and radiography on the same day. Two blinded radiologists independently evaluated the tomosynthesis images and radiographs for the presence of pulmonary emphysema. Axial and coronal MDCT images served as the reference standard and the percentage lung volume with attenuation values of -950 HU or lower (LAA-950) was evaluated to determine the extent of emphysema. Receiver-operating characteristic (ROC) analysis and generalised estimating equations model were used. ROC analysis revealed significantly better performance (P -950. The diagnostic performance of tomosynthesis was significantly superior to that of radiography for the detection of pulmonary emphysema. In both tomosynthesis and radiography, the sensitivity was affected by the LAA-950. (orig.)

  2. Assessing the impact of computed radiography and PACS

    The authors' institution is a VA pilot center for total digital imaging and PACS. They are gathering quantitative service delivery and cost data before, during, and after stepwise implementation of computed radiography and PACS at our institution to define the impact on imaging service delivery. They designed a simple audit method using the X-ray request and time clocks to determine patient waiting time, imaging time, film use, image availability to the radiologist, matching of current with previous images, image availability to clinicians, and time to final interpretation. Their department model is a multichannel, multiserver patient queue. Their current radiograph file is space limited. Their preimplementation audit showed some long waiting times (40 minutes, average 20) and immediate retrieval of prior films in only 42% of cases, with an average retrieval time of 22 hours. Computed radiography and the optical archive have the potential to improve these figures. The audit will be ongoing and automated as implementation of PACS progresses, to measure service improvement and learning curve with the new equipment. This paper presents the audit format and baseline preimplementation figures

  3. Assessing The Impact Of Computed Radiography And PACS

    Hedgcock, Marcus W.; Kehr, Katherine

    1989-05-01

    Our institution (San Francisco VA Medical Center) is a VA pilot center for total digital imaging and PACS. Quantitative information about PACS impact on health care is limited, because no centers have done rigorous preimplementation studies. We are gathering quantitative service delivery and cost data before, during, and after stepwise implementation of computed radiography and PACS at our institution to define the impact on imaging service delivery. We designed a simple audit method using the x-ray request and time clocks to determine patient waiting time, imaging time, film use, image availability to the radiologist, matching of current with previous images, image availability to clinicians, and time to final interpretation. Our department model is a multichannel, mulitserver patient queue. Our current radiograph file is space limited, containing only one year of images; older images are kept in a remote file area in another building. In addition, there are 16 subfile areas within the Radiology Service and the medical center. Our preimplementation audit showed some long waiting times (40 minutes, average 20) and immediate retrieval of prior films in only 42% of cases, with an average retrieval time of 22 hours. Computed radiography and the optical archive have the potential to improve these figures. The audit will be ongoing and automated as implementation of PACS progresses, to measure service improvement and learning curve with the new equipment. We present the audit format and baseline preimplementation figures.

  4. Technical and clinical breast cancer screening performance indicators for computed radiography versus direct digital radiography

    Bosmans, Hilde; Lemmens, Kim; Zanca, Federica; Ongeval, Chantal van; Steen, Andre van [University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Hauwere, An de; Thierens, Hubert [Ghent University, QCC, Ghent (Belgium); Herck, Koen van; Bleyen, Luc; Mortier, Griet [Ghent University, Centrum voor Preventie en Vroegtijdige Opsporing van Kanker, Department of Public Health, Ghent (Belgium); Martens, Patrick [Vroegtijdige Opsporing Borstklierkanker West-Vlaanderen vzw, Bruges (Belgium); Putte, Gretel vande; Kellen, Eliane; Limbergen, Erik van [Leuven University Center of Cancer Screening, Leuven (Belgium)

    2013-10-15

    To compare technical and clinical screening performance parameters between computed radiography (CR) and direct digital radiography (DR) systems. The number of women screened with CR was 73,008 and with DR 116,945. Technical and patient dose survey data of 25 CR and 37 DR systems were available. Technical performance was expressed by threshold thickness values at the mean glandular dose (MGD) level of routine practice. Clinical indicators included recall rate (RR), cancer detection rate (CDR), percentage of ductal carcinoma in situ (DCIS), percentage of cancers with T-scores smaller than 1 cm and positive predictive value (PPV). Contrast threshold values for the 0.1-mm gold disk were 1.44 {mu}m (SD 0.13 {mu}m) for CR and 1.20 {mu}m (SD 0.13 {mu}m for DR). MGD was 2.16 mGy (SD 0.36 mGy) and 1.35 mGy (SD 0.32 mGy) for CR and DR respectively. We obtained for CR, respectively DR, the following results: RR in the first round of 5.48 % versus 5.61 %; RR in subsequent rounds of 2.52 % versus 2.65 %; CDR of 0.52 % versus 0.53 %; DCIS of 0.08 % versus 0.11 %; a rate of cancers with T-scores smaller than 1 cm of 0.11 % versus 0.11 %; PPV of 18.45 % versus 18.64 %; none of them was significantly different. Our screening indicators are reassuring for the use of CR and DR, with CR operating at 60 % higher MGD. (orig.)

  5. Conventional radiography and computed tomography of cardiac assist devices

    Patients intended for circulatory support by cardiac assist devices (CAD) usually suffer from end-stage acute or chronic heart failure. Since the introduction of CAD in 1963 by DeBakey and coworkers, the systems have gone through a substantial evolution and have been increasingly used in the intervening decades. The spectrum of CAD includes a variety of systems serving to assist the systolic function of the left ventricle, the right ventricle, or both. Conventional radiography and multislice spiral computed tomography (CT) are the most commonly used radiological techniques for imaging patients with a CAD. CT is very useful for evaluating CAD systems by using both two- and three-dimensional reconstructions of the volumetric data sets. The two techniques together allow for the comprehensive assessment of patients with devices by imaging the in- and outflow cannulae, the anastomoses, the position of the pump, as well as associated complications. A close collaboration with cardiac surgeons with expertise in the field of circulatory support is deemed necessary for adequate image interpretation. This article describes the technical diversity of the currently available CAD systems. The imaging characteristics on conventional radiography and multislice spiral CT as well as the typical complications of their use are demonstrated. (orig.)

  6. Research to exploit, utilize computed radiography system and build suitable process

    CR is computed radiography method. CR35 is digital radiography equipment which has just equipped in Viet Nam at the end of 2009 by VIE8020 project. The system include image plate (IP) to change for film, CR35 equipment which scans and records IPs signal by laser light and converts to digital image. This system can replaces of film radiography at any where has possible infrastructure like stable power supply, flat, etc. The research purpose is to use the CR35 system, own equipment and technology, compile technical documents and process guide for practice computed radiography. (author)

  7. Demonstration of neutron radiography and computed tomography at the University of Texas thermal neutron imaging facility

    A thermal neutron imaging facility for real-time neutron radiography and computed tomography has recently been developed and built at the University of Texas TRIGA reactor. Herein the authors present preliminary results of radiography and tomography test experiments. These preliminary results showed that the beam is of high quality and is suitable for radiography and tomography applications. A more detailed description of the facility is given elsewhere

  8. Comparison of computed tomography and radiography for detecting changes induced by malignant nasal neoplasia in dogs

    The ability of computed tomography and radiography to detect changes associated with nasal neoplasia was compared in dogs. Eighteen areas or anatomic structures were evaluated in 21 dogs for changes indicative of neoplasia. Computed tomography was superior (P < or = 0.05) to radiography for detecting changes in 14 of 18 areas. Radiography was not superior for detecting changes in any structure or area. Computed tomography reveals vital information not always detected radiographically to assist in providing a prognosis and in planning treatment for nasal neoplasms in dogs

  9. A benchmark for comparison of dental radiography analysis algorithms.

    Wang, Ching-Wei; Huang, Cheng-Ta; Lee, Jia-Hong; Li, Chung-Hsing; Chang, Sheng-Wei; Siao, Ming-Jhih; Lai, Tat-Ming; Ibragimov, Bulat; Vrtovec, Tomaž; Ronneberger, Olaf; Fischer, Philipp; Cootes, Tim F; Lindner, Claudia

    2016-07-01

    Dental radiography plays an important role in clinical diagnosis, treatment and surgery. In recent years, efforts have been made on developing computerized dental X-ray image analysis systems for clinical usages. A novel framework for objective evaluation of automatic dental radiography analysis algorithms has been established under the auspices of the IEEE International Symposium on Biomedical Imaging 2015 Bitewing Radiography Caries Detection Challenge and Cephalometric X-ray Image Analysis Challenge. In this article, we present the datasets, methods and results of the challenge and lay down the principles for future uses of this benchmark. The main contributions of the challenge include the creation of the dental anatomy data repository of bitewing radiographs, the creation of the anatomical abnormality classification data repository of cephalometric radiographs, and the definition of objective quantitative evaluation for comparison and ranking of the algorithms. With this benchmark, seven automatic methods for analysing cephalometric X-ray image and two automatic methods for detecting bitewing radiography caries have been compared, and detailed quantitative evaluation results are presented in this paper. Based on the quantitative evaluation results, we believe automatic dental radiography analysis is still a challenging and unsolved problem. The datasets and the evaluation software will be made available to the research community, further encouraging future developments in this field. (http://www-o.ntust.edu.tw/~cweiwang/ISBI2015/). PMID:26974042

  10. Comparison of clinical and physical measures of image quality in chest and pelvis computed radiography at different tube voltages.

    Sandborg, Michael; Tingberg, Anders; Ullman, Gustaf; Dance, David R; Alm Carlsson, Gudrun

    2006-11-01

    The aim of this work was to study the dependence of image quality in digital chest and pelvis radiography on tube voltage, and to explore correlations between clinical and physical measures of image quality. The effect on image quality of tube voltage in these two examinations was assessed using two methods. The first method relies on radiologists' observations of images of an anthropomorphic phantom, and the second method was based on computer modeling of the imaging system using an anthropomorphic voxel phantom. The tube voltage was varied within a broad range (50-150 kV), including those values typically used with screen-film radiography. The tube charge was altered so that the same effective dose was achieved for each projection. Two x-ray units were employed using a computed radiography (CR) image detector with standard tube filtration and antiscatter device. Clinical image quality was assessed by a group of radiologists using a visual grading analysis (VGA) technique based on the revised CEC image criteria. Physical image quality was derived from a Monte Carlo computer model in terms of the signal-to-noise ratio, SNR, of anatomical structures corresponding to the image criteria. Both the VGAS (visual grading analysis score) and SNR decrease with increasing tube voltage in both chest PA and pelvis AP examinations, indicating superior performance if lower tube voltages are employed. Hence, a positive correlation between clinical and physical measures of image quality was found. The pros and cons of using lower tube voltages with CR digital radiography than typically used in analog screen-film radiography are discussed, as well as the relevance of using VGAS and quantum-noise SNR as measures of image quality in pelvis and chest radiography. PMID:17153395

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

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

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

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

    2010-12-01

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

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

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

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

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

  15. Comparison of storage phosphor computed radiography with conventional film-screen radiography in the recognition of pneumoconiosis

    Laney, A.S.; Petsonk, E.L.; Wolfe, A.L.; Attfield, M.D. [National Institute of Occupational Safety & Health, Morgantown, WV (USA)

    2010-07-15

    Traditional film-screen radiography (FSR) has been useful in the recognition and evaluation of interstitial lung diseases, but is becoming increasingly obsolete. To evaluate the applicability of storage phosphor digital computed radiography (CR) images in the recognition of small lung opacities, we compared image quality and the profusion of small opacities between FSR and CR radiographs. We screened 1,388 working coal miners during the course of the study with FSR and CR images obtained on the same day from all participants. Each traditional chest film was independently interpreted by two of eight experienced readers using the International Labour Office (ILO) classification of radiographs of pneumoconiosis, as were CR images displayed on medical-grade computer monitors. The prevalence of small opacities (ILO category 1/0 or greater) did not differ between the two imaging modalities (5.2% for FSR and 4.8% for soft copy CR; p. 0.50). Inter-reader agreement was also similar between FSR and CR. Significant differences between image modalities were observed in the shape of small opacities, and in the proportion of miners demonstrating high opacity profusion (category 2/1 and above). Our results indicate that, with appropriate attention to image acquisition and soft copy display, CR digital radiography can be equivalent to FSR in the identification of small interstitial lung opacities.

  16. Computed Tomography and Computed Radiography of late Bronze Age Cremation Urns from Denmark

    Harvig, Lise Lock; Lynnerup, Niels; Amsgaard Ebsen, Jannie

    2012-01-01

    To improve methods used to study prehistoric cremation rituals, cremation urns from the Danish late Bronze Age were examined using Computed Tomography and Computed Radiography (Digital X-ray). During microexcavation, the digital images were used as registration tool. Our results suggest that...... osteological ageing and sexing are more accurate when combining CT-images with excavated remains. Digital volume rendering further enables a compromised estimation of original cremation weight. Microexcavation is clearly a primary cause of bone fragmentation. Cremated remains affected by lower cremation...

  17. Development of computer-aided auto-ranging technique for a computed radiography system

    For a computed radiography system, the authors developed a computer-aided autoranging technique in which the clinically useful image data are automatically mapped to the available display range. The preread image data are inspected to determine the location of collimation. A histogram of the pixels inside the collimation is evaluated regarding characteristic values such as maxima and minima, and then the optimal density and contrast are derived for the display image. The effect of the autoranging technique was investigated at several hospitals in Japan. The average rate of films lost due to undesirable density or contrast was about 0.5%

  18. Neutron-computer tomography using real-time neutron radiography

    A real-time neutron radiography facility was constructed including the capability of neutron tomography. The neutron beam was measured for total neutron flux ((1.0 +/- 0.2) x 1011 m/(m2-sec)), gold cadmium ratio (52 +/- 3) and effective neutron temperature (830C +/- 80C). The angular divergence or nonparallelism of the neutron beam was measured to be 2.30 +/- 0.10 thereby providing a means of quantifying the collimator effectiveness. The resolution capabilities of both static film and real-time neutron radiographs were quantified using a Fourier transform algorithm to calculate the modulation transfer function of both types of radiographs. The contrast sensitivity of both types of radiographs. The contrast sensitivity of both types of radiographs was measured as 3.1% for film and 4.0% for real-time radiographs. Two tomography algorithms, the simultaneous iterative reconstruction technique (SIRT) and the convolution method, were programmed on an Intellect 100 Image Processing System. The SIRT algorithm was found to be too large and slow on the Intellect 100 to produce useful tomographs. The convolution method produced results near the theoretical resolution limits for a given number of projections. A tomographic resolution of at least 1.3 mm was demonstrated using 200 projections. Computer running time for the convolution method was found to be ∼ 30 seconds for each projection used. A series of experiments were conducted using the convolution method investigating the effect of high and low pass filtering, diagonal line enhancement and contrast stretching on the finished tomographs. These experiments showed that spatial resolution is not generally improved by these filtering functions but contrast sensitivity of the tomographs is improved

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

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

    2015-09-15

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

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

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

  1. Daily quality control in computed radiography mammography using the manufacturer phantom

    Jakubiak, Rosangela R.; Messias, Pricila C.; Oliveira, Carlla M., E-mail: requi@utfpr.edu.br [Technological Federal University of Parana (UTFPR), Curitiba, PR (Brazil). Academic Physics Dept.

    2011-07-01

    The quality control (QC) in mammography system involves a large amount of test tools, which implies a large space for storage and a high number of exposure. This work describes a QC system using a phantom, Fuji Computed Radiography (FCR) One Shot Phantom M Plus, that evaluates several parameters with just one exposure. The software offers tests with annual, semi-annual, quarterly, weekly and daily periodicity, and analyzes the conformities of the mammography equipment, image plate and cassettes. Because of the high number of tests, it was evaluated the daily test only for seven months in two mammography equipment. The test, through the software and its image, allows the analysis of ten parameters in QC. The evaluation of these parameters was realized by the average of the values provided by the software. Only one of the evaluated items showed not conformity, but this was observed and the necessary corrections were realized. The monitoring of use of FCR Mammography QC software with the FCR One Shot Phantom M Plus was realized and through this we could investigate that the quality program provided by the system is appropriate for the radiology services that has the Fuji Computed Radiography system. (author)

  2. A computer-aided diagnosis approach for emphysema recognition in chest radiography.

    Coppini, Giuseppe; Miniati, Massimo; Monti, Simonetta; Paterni, Marco; Favilla, Riccardo; Ferdeghini, Ezio Maria

    2013-01-01

    The purpose of this work is twofold: (i) to develop a CAD system for the assessment of emphysema by digital chest radiography and (ii) to test it against CT imaging. The system is based on the analysis of the shape of lung silhouette as imaged in standard chest examination. Postero-anterior and lateral views are processed to extract the contours of the lung fields automatically. Subsequently, the shape of lung silhouettes is described by polyline approximation and the computed feature-set processed by a neural network to estimate the probability of emphysema. Images of radiographic studies from 225 patients were collected and properly annotated to build an experimental dataset named EMPH. Each patient had undergone a standard two-views chest radiography and CT for diagnostic purposes. In addition, the images (247) from JSRT dataset were used to evaluate lung segmentation in postero-anterior view. System performances were assessed by: (i) analyzing the quality of the automatic segmentation of the lung silhouette against manual tracing and (ii) measuring the capabilities of emphysema recognition. As to step i, on JSRT dataset, we obtained overlap percentage (Ω) 92.7±3.3%, Dice Similarity Coefficient (DSC) 95.5±3.7% and average contour distance (ACD) 1.73±0.87 mm. On EMPH dataset we had Ω=93.1±2.9%, DSC=96.1±3.5% and ACD=1.62±0.92 mm, for the postero-anterior view, while we had Ω=94.5±4.6%, DSC=91.0±6.3% and ACD=2.22±0.86 mm, for the lateral view. As to step ii, accuracy of emphysema recognition was 95.4%, with sensitivity and specificity 94.5% and 96.1% respectively. According to experimental results our system allows reliable and inexpensive recognition of emphysema on digital chest radiography. PMID:22522287

  3. Ultrasonography in the diagnosis of nasal bone fractures: a comparison with conventional radiography and computed tomography.

    Lee, In Sook; Lee, Jung-Hoon; Woo, Chang-Ki; Kim, Hak Jin; Sol, Yu Li; Song, Jong Woon; Cho, Kyu-Sup

    2016-02-01

    The purpose of this study was to evaluate and compare the diagnostic efficacy of ultrasonography (US) with radiography and multi-detector computed tomography (CT) for the detection of nasal bone fractures. Forty-one patients with a nasal bone fracture who underwent prospective US examinations were included. Plain radiographs and CT images were obtained on the day of trauma. For US examinations, radiologist used a linear array transducer (L17-5 MHz) in 24 patients and hockey-stick probe (L15-7 MHz) in 17. The bony component of the nose was divided into three parts (right and left lateral nasal walls, and midline of nasal bone). Fracture detection by three modalities was subjected to analysis. Furthermore, findings made by each modality were compared with intraoperative findings. Nasal bone fractures were located in the right lateral wall (n = 28), midline of nasal bone (n = 31), or left lateral wall (n = 31). For right and left lateral nasal walls, CT had greater sensitivity and specificity than US or radiography, and better agreed with intraoperative findings. However, for midline fractures of nasal bone, US had higher specificity, positive predictive value, and negative predictive value than CT. Although two US evaluations showed good agreements at all three sites, US findings obtained by the hockey-stick probe showed closer agreement with intraoperative findings for both lateral nasal wall and midline of nasal bone. Although CT showed higher sensitivity and specificity than US or radiography, US found to be helpful for evaluating the midline of nasal bone. Furthermore, for US examinations of the nasal bone, a smaller probe and higher frequency may be required. PMID:25749616

  4. Computed tomography, ultrasonography and plain radiography in the detection of foreign bodies in pork muscle tissue

    To evaluate the possibility to detect foreign bodies in superficial soft tissue a comparative study including computed tomography, ultrasonography and plain radiography, is presented. Nine different materials, ranging in size from 2x3 to 3x10 mm, were inserted into pork muscle. All foreign bodies were detected and exact location was achieved using computed tomography and ultrasonography. In plain radiography wood was not visualised and exact location of all foreign bodies was not obtained. According to our results computed tomography and ultrasonography is useful in detecting foreign bodies in superficial soft tissue. (orig.)

  5. Digital Detectors: Computed Radiography (CR for All Radiologists

    Frans Dhaenens

    2007-08-01

    Full Text Available Introduction: Digital techniques in radiology have many advantages for radiologists, radiographers, patients, clinicians and hospital-operators from many perspectives: diagnostic quality, dose reduction, access to old and new images and reports via PACS, HIS and RIS."nRadiologists concentrate more and more on organs and pathology (super specialties rather than in modalities. Organ based radiology requires the integration of all modalities and has to cover large geographical regions to deliver expertise, as there few top-experts. This is only possible in the digital world of HICT (Health Information and Communication Technology, where digital detectors are the first step in a long chain of informatics."nToday most of the diagnostic imaging modalities (CT, MRI, US, PET,.. used in radiology are digital except plain film imaging. In order to digitize plain x-ray (also called General Radiology there is choice between Computed Radiography (CR based upon storage phosphor screens and DR (Digital Radiography based on "flat or panel" detectors. A large spectrum of applications and price ranges is available on the market."nTechnology: Both CR and DR rely on conversion and storage of x-ray energy in "pixel"-like elements in the detector. These detectors are linear (film is S-curved and have a enormous dynamic range (1 in 100.000 so no information is lost and they resist over- and under-exposure up to 4 times."n- In CR x-ray energy is stored into the phosphor-crystals and converted into visible light after stimulation by (laser light which is in turn captured and digitized by an optical system. Pixels (in size between 50 and 150 µm are one after one stimulated and translated into a digital image of millions of points. "n- In DR systems x-ray energy is converted in 2 or 3 steps into electrical charge that is stored in every pixel of the detector. These charges are digitized row after row to make a digital image. The conversion of the x-rays is done by a

  6. Computed radiography versus mobile direct radiography for bedside chest radiographs: Impact of dose on image quality and reader agreement

    Aim: To asses the image quality and potential for dose reduction of mobile direct detector (DR) chest radiography as compared with computed radiography (CR) for intensive care unit (ICU) chest radiographs (CXR). Methods and materials: Three groups of age-, weight- and disease-matched ICU patients (n = 114 patients; 50 CXR per acquisition technique) underwent clinically indicated bedside CXR obtained with either CR (single read-out powder plates) or mobile DR (GOS-TFT detectors) at identical or 50% reduced dose (DR50%). Delineation of anatomic structures and devices used for patient monitoring, overall image quality and disease were scored by four readers. In 12 patients pairs of follow-up CR and DR images were available, and in 15 patients pairs of CR and DR50% images were available. In these pairs the overall image quality was also compared side-by-side. Results: Delineation of anatomy in the mediastinum was scored better with DR or DR50% than with CR. Devices used for patient monitoring were seen best with DR, with DR50% being superior to CR. In the side-by-side comparison, the overall image quality of DR and DR50% was rated better than CR in 96% (46/48) and 87% (52/60), respectively. Inter-observer agreement for the assessment of pathology was fair for CR and DR50% (κ = 0.33 and κ = 0.39, respectively) and moderate for DR (κ = 0.48). Conclusion: Mobile DR units offer better image quality than CR for bedside chest radiography and allow for 50% dose reduction. Inter-observer agreement increases with image quality and is superior with DR, while DR50% and CR are comparable.

  7. Observer variation for radiography, computed tomography, and magnetic resonance imaging of occult hip fractures

    Collin, David; Dunker, Dennis; Goethlin, Jan H (Dept. of Radiology, Sahlgrenska Univ. Hospital, Moelndal (Sweden)), email: david.collin@vgregion.se; Geijer, Mats (Center for Medical Imaging and Physiology, Skaane Univ. Hospital, Lund Univ., Lund (Sweden))

    2011-10-15

    Background Conventional radiography is insufficient for diagnosis in a small but not unimportant number of hip fractures, and secondary imaging with computed tomography (CT) or magnetic resonance imaging (MRI) is warranted. There are no convincing observer variation studies performed for conventional radiography or CT in occult fractures, and no large materials for MRI. Purpose To assess observer variation in radiography, CT and MRI of suspected occult, non-displaced hip fractures, and to evaluate to what extent observer experience or patient age may influence observer performance. Material and Methods A total of 375 patients after hip trauma where radiography was followed by CT or MRI to evaluate a suspected occult hip fracture were collected retrospectively from two imaging centers. After scoring by three observers with varying degrees of radiologic experience, observer variation was assessed by using linear weighted kappa statistics. Results For radiography, agreements between the three observers were moderate to substantial for intra capsular fractures, with kappa values in the ranges of 0.56-0.66. Kappa values were substantial for extracapsular fractures, in the ranges of 0.69-0.72. With increasing professional experience, fewer fractures were classified as equivocal at radiography. For CT and MRI, observer agreements were similar and almost perfect, with kappa values in the ranges of 0.85-0.97 and 0.93-0.97. Conclusion There were almost perfect observer agreements for CT and MRI in diagnosing non-displaced, occult hip fractures. Observer agreements for radiography were moderate to substantial, and observer experience influenced agreement only at radiography

  8. Observer variation for radiography, computed tomography, and magnetic resonance imaging of occult hip fractures

    Background Conventional radiography is insufficient for diagnosis in a small but not unimportant number of hip fractures, and secondary imaging with computed tomography (CT) or magnetic resonance imaging (MRI) is warranted. There are no convincing observer variation studies performed for conventional radiography or CT in occult fractures, and no large materials for MRI. Purpose To assess observer variation in radiography, CT and MRI of suspected occult, non-displaced hip fractures, and to evaluate to what extent observer experience or patient age may influence observer performance. Material and Methods A total of 375 patients after hip trauma where radiography was followed by CT or MRI to evaluate a suspected occult hip fracture were collected retrospectively from two imaging centers. After scoring by three observers with varying degrees of radiologic experience, observer variation was assessed by using linear weighted kappa statistics. Results For radiography, agreements between the three observers were moderate to substantial for intra capsular fractures, with kappa values in the ranges of 0.56-0.66. Kappa values were substantial for extracapsular fractures, in the ranges of 0.69-0.72. With increasing professional experience, fewer fractures were classified as equivocal at radiography. For CT and MRI, observer agreements were similar and almost perfect, with kappa values in the ranges of 0.85-0.97 and 0.93-0.97. Conclusion There were almost perfect observer agreements for CT and MRI in diagnosing non-displaced, occult hip fractures. Observer agreements for radiography were moderate to substantial, and observer experience influenced agreement only at radiography

  9. Radiological protection procedures for industrial applications of computed radiography; Procedimentos de protecao radiologica em aplicacoes industriais da radiografia computadorizada

    Aquino, Josilto Oliveira de

    2009-03-15

    Due to its very particular characteristics, industrial radiography is responsible for roughly half of the relevant accidents in nuclear industry, in developed as well as in developing countries, according to the International Atomic Energy Agency (IAEA). Thus, safety and radiological protection in industrial gamma radiography have been receiving especial treatment by regulatory authorities of most Member States. The main objective of the present work was to evaluate, from the radioprotection point of view, the main advantages of computed radiography (CR) for filmless industrial radiography. In order to accomplish this, both techniques, i.e. conventional and filmless computed radiography were evaluated and compared through practical studies. After the studies performed at the present work it was concluded that computed radiography significantly reduces the inherent doses, reflecting in smaller restricted areas and costs, with consequent improvement in radiological protection and safety. (author)

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

    American Society for Testing and Materials. Philadelphia

    2010-01-01

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

  11. Neutron Radiography Analysis of a Transient Liquid Phase Joint

    Ballhausen, H.; Abele, H.; Eccleston, R. S.; Gaehler, R.; Smith, A. J.; A. Steuwer; Van Overberghe, A.

    2006-01-01

    Neutron radiography in many cases is the only non-destructive technique available for the analysis of a wide range of samples from metallurgy, materials engineering and materials testing. In this paper the potential of the technique is illustrated for a transient liquid phase (TLP) joint. TLP bonding produces interface free and stress free joints. The quality and properties of the joint depend on the diffusion of an interlayer into the base material. A TLP joint is visualised and the diffusio...

  12. Calculation and analysis of the neutron radiography spatial resolution

    Background: Spatial resolution is the key parameter for neutron radiography facility. A model of the integrated system resolution is important when designing or using a system to ensure that the realistic resolution goals can be established and achieved. Purpose: For this resolution modeling analysis we focused on the effects of the geometry effects of L/D, the optical diffusion response of the scintillator and the sampling at the sensor (CCD or CMOS camera) and a formula was derived indicating their functional relationship. Methods: This resolution modeling analysis has been down by theoretic calculations. Then this integrated system resolution model was used as an empirical methodology to verify and optimize the performance of the detection system for real-time neutron radiography at China Advance Research Reactor. Results: The special resolutions at very collimation conditions have been calculation by using this method. And three of important parameters of this resolution model have been discussed to optimize the system performance. Conclusion: These resolution analysis concepts and methods will benefit both the design and the characterization of radiography systems. (authors)

  13. The clinical application of computed radiography in bedside photography of newborn

    Objective: To evaluate the computed radiography in bedside photography of newborn, especially in chest radiography. Methods: Bedside CR images were selected in 100 cases randomly. The exposure parameters were optimized using the large latitude of CR. The details of images were post-processed and adjusted using spatial tuning technique. Then CR photography was compared with conventional X-ray photography. Results: The images acquired with CR had good contrast, high definition, and little distortion, in which the condemned image rate was 1%. While in conventional X-ray photography, the unsuccessful imaging rate is 9%. Conclusion: Bedside computed radiography of new-born, especially the chest imaging, is very helpful to improve image quality and positive rate of the diagnosis. (authors)

  14. Cholesteatoma: computed tomography and radiography in a dog

    Cholesteatoma, a rare and/or misdiagnosed disease, results of a serious complication in dogs with chronic otitis. This article describes a case of a dachshund sent to the veterinary hospital presenting signs of cognitive dysfunction associated to peripheral neuropathy of the facial nerve on the right side. At radiography, an enlargement and thickness of the contours associated with loss of anatomical definition of the right tympanic bulla compared to the left was seen. At tomography, this enlargement and thickness were seen with better definition, besides the fulfilling by hyperdense calcified content, bullae osteolysis and temporal bone sclerosis at the same side. (author)

  15. Diagnostic value of computed tomography, radiography and ultrasonography in metacarpophalangeal joint disorders in horses

    V.M.V. Machado

    2016-02-01

    Full Text Available In modern society the work and athletic performance of horses has led to a very important animal production sector in which Brazil possesses the third largest horse stock. Among all equine lesions described, metacarpophalangeal (fetlock joint lesions are considered one of the main causes of lameness. Consequently, there is a need to improve the understanding and diagnosis of these injuries. The most efficient imaging diagnostic methods for the fetlock region are computed tomography, radiography and ultrasound. Imaging studies of the anatomical structures involving this joint are extremely important to obtain a more precise diagnose. The present study was performed in order to evaluate the capacity of different imaging diagnostic modalities to detect a variety of lesions in different fetlock structures. Twenty horses (Equus caballus used for horsemanship activities were referred to the Department of Animal Reproduction and Veterinary Radiology of São Paulo State University, Botucatu campus, with clinical signs of metacarpophalangeal joint injuries. Horses were submitted to radiographic and ultrasonographic exam and computed tomography scan. Image analysis revealed a significant capacity of these methods to characterize lesions in this region. However, computed tomography provided broader and better evaluation of lesions in bones and adjacent structures, because it allows the analysis to be performed on three-dimensional projections, with attenuation coefficients (window selections and tissue density measurement through Hounsfield Units (HU.

  16. First Results and Realization Status of a Proton Computed Radiography Device

    Sipala, V. [Dipt. di Fisica, Univ. degli Studi di Catania, via S. Sofia 64, I-95123, Catania (Italy); INFN, sezione di Catania, via S. Sofia 64, I-95123, Catania (Italy); Bruzzi, M. [Dipt. di Energetica, Univ. degli Studi di Firenze, via S. Marta 3, I-50139 Firenze (Italy); INFN, sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino (Italy); Bucciolini, M. [INFN, sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino (Italy); Dipt. di Fisiopatologia Clinica, Univ. degli Studi di Firenze, v.le Morgagni 85, I-50134 Firenze (Italy); Candiano, G. [Lab. Nazionali del Sud-INFN, via S. Sofia 62, I-95123, Catania (Italy); Capineri, L. [Dipt. di Elettronica e Telecomunicazioni, Univ. degli Studi di Firenze, via S. Marta 3, I-50139 Firenze (Italy); Cirrone, G.A.P. [Lab. Nazionali del Sud-INFN, via S. Sofia 62, I-95123, Catania (Italy); Civinini, C. [INFN, sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino (Italy); Cuttone, G. [Lab. Nazionali del Sud-INFN, via S. Sofia 62, I-95123, Catania (Italy); Lo Presti, D. [Dipt. di Fisica, Univ. degli Studi di Catania, via S. Sofia 64, I-95123, Catania (Italy); INFN, sezione di Catania, via S. Sofia 64, I-95123, Catania (Italy); Marrazzo, L. [INFN, sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino (Italy); Dipt. di Fisiopatologia Clinica, Univ. degli Studi di Firenze, v.le Morgagni 85, I-50134 Firenze (Italy); Menichelli, D. [Dipt. di Energetica, Univ. degli Studi di Firenze, via S. Marta 3, I-50139 Firenze (Italy); INFN, sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino (Italy); Randazzo, N. [INFN, sezione di Catania, via S. Sofia 64, I-95123, Catania (Italy); Talamonti, C. [INFN, sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino (Italy); Dipt. di Fisiopatologia Clinica, Univ. degli Studi di Firenze, v.le Morgagni 85, I-50134 Firenze (Italy)

    2009-12-15

    The PRIMA (PRoton IMAging) collaboration, supported by INFN and MIUR, is realizing a proton Computed Radiography device suitable to acquire the single proton with 1MHz rate for application in proton therapy. Its design and the first results obtained are presented.

  17. First Results and Realization Status of a Proton Computed Radiography Device

    The PRIMA (PRoton IMAging) collaboration, supported by INFN and MIUR, is realizing a proton Computed Radiography device suitable to acquire the single proton with 1MHz rate for application in proton therapy. Its design and the first results obtained are presented.

  18. Lung cancer screening program using annual chest radiographs with computed radiography (FCR)

    Takashima, Tsutomu; Itoh, Hiroshi; Ikegaki, Shigeru; Chika, Koyata; Nitta, Haruo; Seno, Takashi; Miyashita, Yukichi; Kobayashi, Tadashi

    1987-08-01

    In the Wajima lung cancer screening program conducted under the auspices of Kanazawa University Hospital, Fuji Computed Radiography (FCR) was utilized in a new chest radiography trial. The results of the screening program are that the necessity of repeat examinations due to poor image quality are less common and the method enables detection of small pulmonary nodular shadows which are possibly candidates for surgery. Oblique chest X-ray with FCR is remarkably effective for the detection and the identification of small lesions. However, the disadvantage of slow processing and high cost must be fully satisfied if FCR is to become a new imaging modality for mass screening.

  19. Evaluation of diagnostic accuracy of conventional and digital periapical radiography, panoramic radiography, and cone-beam computed tomography in the assessment of alveolar bone loss

    Takeshita, Wilton Mitsunari; Vessoni Iwaki, Lilian Cristina; Da Silva, Mariliani Chicarelli; Tonin, Renata Hernandes

    2014-01-01

    Background: To evaluate the diagnostic accuracy of different radiographic methods in the assessment of proximal alveolar bone loss (ABL). Materials and Methods: ABL, the distance between cement-enamel junction and alveolar bone crest, was measured in 70 mandibular human teeth – directly on the mandibles (control), using conventional periapical radiography with film holders (Rinn XCP and Han-Shin), digital periapical radiography with complementary metal-oxide semiconductor sensor, conventional panoramic, and cone-beam computed tomography (CBCT). Three programs were used to measure ABL on the images: Image tool 3.0 (University of Texas Health Sciences Center, San Antonio, Texas, USA), Kodak Imaging 6.1 (Kodak Dental Imaging 6.1, Carestream Health®, Rochester, NY, USA), and i-CAT vision 1.6.20. Statistical analysis used ANOVA and Tukey's test at 5% significance level. Results: The tomographic images showed the highest means, whereas the lowest were found for periapical with Han-Shin. Controls differed from periapical with Han-Shin (P digital periapical (P = 0.0027). Conventional periapicals with film holders differed from each other (P = 0.0007). Digital periapical differed from conventional periapical with Han-Shin (P = 0.0004). Conclusions: Conventional periapical with Han-Shin film holder was the only method that differed from the controls. CBCT had the closest means to the controls. PMID:25191066

  20. Analyze image quality and comparative study between conventional and computed radiography applied to the inspection of alloys

    Piping system design takes into account relevant factors such as: internal coating, dimensioning, vibration system, adequate supports and principally, piping material. Cost is a decisive factor in the phase of material selection. The non-destructive testing method most commonly employed in industry to analyze the structure of an object is radiographic testing. Computed radiography (CR) is a quicker and much more efficient alternative to conventional radiography but, although CR presents numerous advantages, testing procedures are still largely based on trial and error, due to the lack of a consecrated methodology to choose parameters as it exists for conventional radiography. Notwithstanding, this paper presents a study that uses the technique of computed radiography to analyze metal alloys. These metal alloys are used as internal pipe coating aiming to protect against corrosion and cracks. This study seeks to evaluate parameters such as basic spatial resolution, Normalized Signal-to-Noise Ratio (SNRN), contrast, intensity and also to compare conventional radiography with CR. (author)

  1. SisRadiologia: a new software tool for analysis of radiological accidents and incidents in industrial radiography

    According to the International Atomic Energy Agency (IAEA), many efforts have been made by Member states, aiming a better control of radioactive sources. Accidents mostly happened in practices named as high radiological risk and classified by IAEA in categories 1 and 2, being highlighted those related to radiotherapy, large irradiators and industrial radiography. Worldwide, more than 40 radiological accidents have been recorded in the industrial radiography. Worldwide, more than 40 radiological accidents have been recorded in the industrial radiography area, involving 37 workers, 110 members of the public and 12 fatalities. Records display 5 severe radiological accidents in industrial radiography activities in Brazil, in which 7 workers and 19 members of the public were involved. Such events led to hands and fingers radiodermatitis, but to no death occurrence. The purpose of this study is to present a computational program that allows the data acquisition and recording in the company, in such a way to ease a further detailed analysis of radiological event, besides providing the learning cornerstones aiming the avoidance of future occurrences. After one year of the 'Industrial SisRadiologia' computational program application - and mostly based upon the workshop about Analysis and Dose Calculation of Radiological Accidents in Industrial Radiography (Workshop sobre Analise e Calculo de dose de acidentes Radiologicos em Radiografia Industrial - IRD 2012), in which several Radiation Protection officers took part - it can be concluded that the computational program is a powerful tool to data acquisition, as well as, to accidents and incidents events recording and surveying in Industrial Radiography. The program proved to be efficient in the report elaboration to the Brazilian Regulatory Authority, and very useful in workers training to fix the lessons learned from radiological events.

  2. SisRadiologia: a new software tool for analysis of radiological accidents and incidents in industrial radiography

    Lima, Camila M. Araujo; Silva, Francisco C.A. da, E-mail: araujocamila@yahoo.com.br, E-mail: dasilva@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Araujo, Rilton A., E-mail: consultoria@maximindustrial.com.br [Maxim Industrial Assessoria TI, Rio de Janeiro, RJ (Brazil)

    2013-07-01

    According to the International Atomic Energy Agency (IAEA), many efforts have been made by Member states, aiming a better control of radioactive sources. Accidents mostly happened in practices named as high radiological risk and classified by IAEA in categories 1 and 2, being highlighted those related to radiotherapy, large irradiators and industrial radiography. Worldwide, more than 40 radiological accidents have been recorded in the industrial radiography. Worldwide, more than 40 radiological accidents have been recorded in the industrial radiography area, involving 37 workers, 110 members of the public and 12 fatalities. Records display 5 severe radiological accidents in industrial radiography activities in Brazil, in which 7 workers and 19 members of the public were involved. Such events led to hands and fingers radiodermatitis, but to no death occurrence. The purpose of this study is to present a computational program that allows the data acquisition and recording in the company, in such a way to ease a further detailed analysis of radiological event, besides providing the learning cornerstones aiming the avoidance of future occurrences. After one year of the 'Industrial SisRadiologia' computational program application - and mostly based upon the workshop about Analysis and Dose Calculation of Radiological Accidents in Industrial Radiography (Workshop sobre Analise e Calculo de dose de acidentes Radiologicos em Radiografia Industrial - IRD 2012), in which several Radiation Protection officers took part - it can be concluded that the computational program is a powerful tool to data acquisition, as well as, to accidents and incidents events recording and surveying in Industrial Radiography. The program proved to be efficient in the report elaboration to the Brazilian Regulatory Authority, and very useful in workers training to fix the lessons learned from radiological events.

  3. Radiography and bone scintigraphy in multiple myeloma: a comparative analysis

    The sensitivity of radionuclide imaging for detecting skeletal lesions was compared with that of radiography by evaluating 573 different anatomical sites in 41 patients with multiple myeloma. Radiography revealed a significantly greater number of myeloma-related bone lesions than did radionuclide imaging. Of the 179 myeloma-related bone lesions detected when both techniques were applied, 163 were seen by radiography and 82 by radionuclide imaging. Ninety-seven lesions were detected by radiography alone and 16 lesions seen by scintiscanning only, yielding a sensitivity of 91% for the former and of 46% for the latter technique. Radionuclide imaging proved superior to radiography only occasionally in the rib cage, and rarely in other anatomical sites. These findings suggest that radiography is the method of first choice in obtaining a skeletal survey in patients with multiple myeloma. In cases with continued pain, unexplained by standard radiography, the skeletal survey should be supplemented by tomography and radionuclide imaging. (author)

  4. Cone beam computed tomography and intraoral radiography for diagnosis of dental abnormalities in dogs and cats

    The development of veterinary dentistry has substantially improved the ability to diagnose canine and feline dental abnormalities. Consequently, examinations previously performed only on humans are now available for small animals, thus improving the diagnostic quality. This has increased the need for technical qualification of veterinary professionals and increased technological investments. This study evaluated the use of cone beam computed tomography and intraoral radiography as complementary exams for diagnosing dental abnormalities in dogs and cats. Cone beam computed tomography was provided faster image acquisition with high image quality, was associated with low ionizing radiation levels, enabled image editing, and reduced the exam duration. Our results showed that radiography was an effective method for dental radiographic examination with low cost and fast execution times, and can be performed during surgical procedures

  5. Quantitative assessment of the impact of computed radiography and PACS on imaging service delivery

    The San Francisco Veterans Administration Medical Center is a pilot center for computed radiography and picture archiving and communications system (PACS). The impact of PACS on health care is unclear because of a lack of rigorous pre- and postimplementation studies. In this paper the authors describe a simple audit method to determine patient waiting time, imaging time, film use, the availability of images to radiologists and clinicians, prior image retrieval, and time to final interpretation. A preimplementation audit showed some lone waiting times (up to 40 minutes; average, 20 minutes), and only 42% immediate retrieval of prior films (average retrieval time, 22 hours). Computed radiography an PACS have the potential to improve these figures

  6. Quantitative Performance Assessment of Computed Radiography for Corrosion Detection in Process Pipes

    Venkatachalam, Rajashekar; Raghu, C.; Pandey, Pramod; Vedula, Venumadhav; Thapa, Prasad; Venugopal, Manoharan

    2007-03-01

    Evaluation of integrity of process pipes in service is an important preventive maintenance issue for power generation and petrochemical industries. Ultrasonic wall thickness is traditionally used to measure wall thickness loss due to corrosion. This technique has various limitations such as need for removal of insulation, point based measurements and unsuitability for high temperature applications. Many have attempted computed radiography to quantify corrosion in pipelines as an alternative technique. Computed Radiography can be carried out without removing insulation and also at higher temperatures. However, the minimum detectability limit of wall thickness loss is limited by various physics complications in radiographic imaging process i.e. scattering, modulation due to detector response, focal spot blurring, the effective thickness of insulation and fluid inside pipe. An attempt has been made to study the effect of insulation and fluid inside pipe on detectability of wall loss due to corrosion using physics simulations and experiments.

  7. Real-time measurement and audit of radiation dose to patients undergoing computed radiography.

    Vano, Eliseo; Fernandez, Jose Miguel; Ten, Jose Ignacio; Guibelalde, Eduardo; Gonzalez, Luciano; Pedrosa, Cesar S A

    2002-10-01

    A real-time patient dose monitoring system for auditing computed radiography is described. Technical data from each exposure and for every examination type are collected and sent by a network to a workstation, which calculates the moving average values of entrance skin dose and dose-area product from the 10 most recently examined patients. Comparison of averages with reference values generates warning messages if reference values are exceeded, prompting corrective action if necessary. PMID:12355017

  8. Automatic measurement system for congenital hip dislocation using a computed radiography

    Acetabular angle which is a diagnostic parameter of congenital hip dislocation has been measured manually in conventional X-ray film system. Using digital image directly provided from a computed radiography, an automatic measurement system was developed for this parameter. The process of the measurement was completed within a reasonable time, and accurate enough. The system was combined with an image database, so that it would be a measurement tool of PACS

  9. Development of a kinetic analysis technique for PACS management and a screening examination in dynamic radiography

    The purpose of this study was to develop a method of kinetic analysis for picture archiving and communication system (PACS) management and computer-aided diagnostic application in dynamic chest radiography. The main analytical technique used in this study was a new algorithm that converts dynamic radiographs into a color-static image. The algorithm is a visualization technique for kinetic information that uses the intensity-density transformation and the direction classification in optical flow. The image made by the new algorithm was defined as a 'kinetic map', and, by analysis using the kinetic map, a patient collation system and nodule detection system were constructed. By analysis that used an artificial neural network of certain feature vectors as kinetic map similarity, the collation system obtained good identification performance. Temporal subtraction processing between a current-status map with simulated nodule and previous-status map detected the region of abnormality as the simulated nodule. It is expected that our method of analysis will be useful as a screening examination for risk management and computer-aided diagnostic application in dynamic chest radiography. (author)

  10. Risk analysis of radiography as a nondestructive testing method

    The risk analysis was made in preparation of a safety manual for the wide variety of applications of industrial radiography. The safety manual is intended to serve as a guide to professionals, presenting the information about safety and health risks involved in a concise though very illustrative manner. The potential risks were listed and evaluated on the occasion of a meeting of experts in October 1999, who used the FMEA analysis, a quality management tool. The following methods or sources were analysed and rated in terms of risks involved: (a) ionizing radiation (b) electric power (c) handling of radioactive radiation sources (d) minor accidents (e) defect equipment (f) activities at construction sites (g) transportation of gear and instruments (h) auxiliary equipment. The risk evaluation presented in the paper also permits identification of problematic aspects in the daily routine. (orig./CB)

  11. A comparison of cathode ray tube (CRT) and computed radiography (CR) diagnosis in mammography

    Kinoshita, Takahiro; Odagiri, Kunio; Andoh, Kazuo; Doiuchi, Tunehiro; Seno, Kengo; Ohtsuka, Toshihiro [Kanagawa Cancer Center, Yokohama (Japan); Matsumoto, Toru

    1999-11-01

    Quantitative evaluation of CRT and CR observations in indentification of malignancy using phantom and clinical data. A breast phantom and a total of 40 patients were imaged by Fuji computed radiography (FCR). The images were interpreted twice by six radiologists both on CR film (2510 x 2000 pixels x 10 bits, 0.1 mm spatial resolution) and on a CRT monitor (1568 x 1152 pixels x 10 bits, 0.1 mm pixel size with double expansion) with image processing parameters of a toutine (RN 1.0, RE 0.2), for a calcification (RN 9.0, RE 4.0) and for a mass (RN 7.0, RE 2.0). The forty clinical cases included breast diseases with calcifications, masses, and normal breasts. Two-tailed t-test was performed to analyze interpretation of simulated microcalcifications and masses in the phantom. The receiver operating characteristic (ROC) analysis was performed to evaluate clinical cases. In all interpretation studies using both breast phantom and clinical cases, there was no significant difference between the two interpretation methods. However the CRT diagnosis was slightly less accurate than CR film diagnosis due to the lower luminance levels of the CRT monitor. Diagnosis via CRT monitor may be substituted for CR film diagnosing breast abnormalities, but the image processing parameters of CRT require improvement to compensate for low luminance. (author)

  12. Lung nodule conspicuity using unsharp mask filters with storage-phosphor-based computed radiography

    Purpose: To compare the performance of various types of unsharp mask filter applied in storage-phosphor-based computed radiography (SR), and to improve the detection of faint nodules of the lung cancer type. Material and Methods: A total of 120 SR radiographs were obtained by means of an anthropomorphous chest phantom and a combination of 3 types of small simulated nodule (5-mm sphere-shaped, and 5-mm and 10-mm hemisphere-shaped) placed on the phantom's surface. Eight combinations of nodule site were selected from 16 predetermined chosen sites, and 5 types of parameter were used for unsharp mask filtering. Eight observers evaluated the images, and the detectability of the lung nodules was evaluated from the images by a ROC analysis. Results: The visibility of the 10-mm hemispherical nodules was nearly equivalent at each site when 5 types of unsharp mask filter were used. The detection of the 5-mm nodules with mid-frequency suppressing and very-low-frequency enhancing filters was better than with a conventional (department standard) mid-frequency enhancing filter. Conclusion: Mid-frequency suppressing versions of the filter helped to demonstrate faint nodular opacity, which is often shown by early bronchogenic carcinoma. This filter could replace conventional filters in the detection of lung nodules. (orig.)

  13. Análise de carcinomas epidermóides por meio de radiografia panorâmica e tomografia computadorizada Analysis of squamous cell carcinomas by means of panoramic radiography and computed tomography

    Amanda Cáceres PEREIRA

    2001-12-01

    Full Text Available Este trabalho teve como objetivo correlacionar aspectos radiográficos como, localização e extensão do tumor, infiltração óssea e de tecidos moles e destruição das corticais, obtidos nas radiografias panorâmicas com os encontrados nas tomografias computadorizadas (TCs. Os aspectos radiográficos de 48 pacientes com diagnóstico histopatológico de carcinomas epidermóides, localizados em várias regiões do complexo buco-maxilo-facial, foram analisados por 4 radiologistas. As radiografias panorâmicas e as tomografias computadorizadas foram realizadas nos hospitais e clínicas da Universidade de Iowa (EUA, FUNDECTO - USP e Hospital Universitário da Universidade de São Paulo (SP, Brasil. Como resultados, obtivemos a grande limitação da radiografia panorâmica em determinar a localização e extensão do tumor, com delimitações bastante imprecisas da lesão. Já as TCs ofereceram resultados mais direcionados como: invasão do tumor em direção a estruturas moles adjacentes, extensão da destruição óssea, bem como a profundidade da lesão, que foram confirmados com os achados cirúrgicos. Concluímos que a tomografia computadorizada demonstrou ser uma técnica bastante sensível na detecção do comprometimento ósseo e do envolvimento de tecidos moles, proporcionando, assim, o auxílio no diagnóstico e no planejamento do tratamento. No entanto, a radiografia panorâmica foi muito pouco sensível e eficaz, por mostrar apenas margens imprecisas e pouco nítidas da lesão, não avaliando o envolvimento de tecidos moles.The purpose of this work was to compare radiographic findings, such as localization and extension of tumors toward the bone and soft tissues, in panoramic radiography and computed tomography (CT. Four radiologists assessed the radiographic findings of 48 patients with the histopathological diagnosis of squamous cell carcinoma in different sites of the maxillofacial region. Panoramic radiographs and computed

  14. Computer-aided diagnosis of pulmonary diseases using x-ray darkfield radiography

    Einarsdottir, Hildur; Yaroshenko, Andre; Velroyen, Astrid;

    2015-01-01

    In this work we develop a computer-aided diagnosis (CAD) scheme for classification of pulmonary disease for grating-based x-ray radiography. In addition to conventional transmission radiography, the grating-based technique provides a dark-field imaging modality, which utilizes the scattering...... properties of the x-rays. This modality has shown great potential for diagnosing early stage emphysema and fibrosis in mouse lungs in vivo. The CAD scheme is developed to assist radiologists and other medical experts to develop new diagnostic methods when evaluating grating-based images. The scheme consists...... manually annotated to build an experimental dataset. System performance was assessed by: (i) determining the quality of the segmentations; (ii) validating emphysema and fibrosis recognition by a linear support vector machine using leave-one-out cross-validation. In terms of segmentation quality, we...

  15. Dose area product measurement for diagnostic reference levels and analysis of patient dose in dental radiography

    In this study, diagnostic reference levels (DRLs) were suggested and patient doses were analysed through the dose-area product value in dental radiography. In intraoral radiography, at three sites, i.e. molar, premolar and incisor on the maxilla and acquired third quartile values: 55.5, 46 and 36.5 mGy cm2, respectively, were measured. In panoramic, cephalo-metric and cone beam computed tomography, the values were 120.3, 146 and 3203 mGy cm2 (16 x 18 cm), respectively. It has been shown that, in intraoral radiography, the patient dose changes proportionally to the value of mA s, but the change in extra-oral radiography in response to mA s could not be confirmed. The authors could confirm, however, the difference in dose according to the manufacturer in all dental radiography examinations, except for panoramic radiography. Depending on the size of hospital, there were some differences in patient dose in intraoral radiography, but no difference in patient dose in extra-oral radiography. (authors)

  16. Comparison of periapical radiography with cone beam computed tomography in the diagnosis of vertical root fractures in teeth with metallic post

    Wilton Mitsunari Takeshita

    2014-01-01

    Full Text Available Aim: To compare the diagnostic accuracy of conventional periapical radiography and cone beam computed tomography (CBCT in detecting vertical root fracture (VRF in tooth with metallic post (MP. Materials and Methods: Twenty endodontically-treated teeth received MPs, artificial fractures were created in 10 teeth, and they were all examined with tomography and radiography. The sample consisted of periapical radiography with post and without post, and tomography with post and without post; each group with five fractured and five non-fractured teeth. The images were evaluated by three dental/maxillofacial radiologists and statistical validations were carried out using receiver operating characteristic (ROC analysis. Results: Sensitivity and specificity of the area under the ROC (Az of tomography with post (Az = 0.953 and without post (Az = 0.956 were significantly higher than those of periapical radiography with post (Az = 0.753 and without post (Az = 0.778. Conclusion: CBCT was more accurate than conventional periapical radiography in detecting VRF.

  17. Cephalometric radiography and computed tomography in infants undergoing craniofacial surgery

    Craniofacial growth after surgery in children is not completely understood. We have therefore formed a programme for pre- and postoperative studies with both roentgencephalometric- and computed tomographic investigations. This regiment results in overlapping information. Thus, an assessment of the advantages and disadvantages of the two methods was made and exemplified in four patients. In our experience both cephalometry and CT are essential for the diagnosis, surgical planning and follow-up of surgically treated children with craniofacial anomalies. To minimize the radiation doses and the diagnostic procedures which in these cases often includes general anesthesia, patients with isolated, asymmetrical conditions such as plagiocephaly, might be followed with CT only, since roentgencephalometry can not add much information. (Authors)

  18. Corrosion monitoring with tangential radiography and limited view computed tomography

    Ewert, Uwe; Tschaikner, Martin; Hohendorf, Stefan; Bellon, Carsten; Haith, Misty I.; Huthwaite, Peter; Lowe, Michael J. S.

    2016-02-01

    Accurate and reliable detection of subsea pipeline corrosion is required in order to verify the integrity of the pipeline. A laboratory trial was conducted with a representative pipe sample. The accurate measurement of the wall thickness and corrosion was performed with high energy X-rays and a digital detector array. A 7.5 MV betatron was used to penetrate a stepped pipe and a welded test pipe of 3 m length and 327 mm outer diameter, with different artificial corrosion areas in the 24 mm thick steel wall. The radiographs were taken with a 40 x 40 cm² digital detector array, which was not large enough to cover the complete pipe diameter after magnification. A C-arm based geometry was tested to evaluate the potential for automated inspection in field. The primary goal was the accurate measurement of wall thickness conforming to the standard. The same geometry was used to explore the ability of a C-arm based scanner in asymmetric mode for computed tomography (CT) measurement, taking projections covering only two thirds of the pipe diameter. The technique was optimized with the modelling software aRTist. A full volume of the pipe was reconstructed and the CT data set was used for reverse engineering, providing a CAD file for further aRTist simulations to explore the technique for subsea inspections.

  19. Studies on image quality optimisation in computed radiography for weld inspection

    The application of metal filters and metal screens improves the image contrast in film radiography. The mechanism of latent X-ray image generation and, its read-out from imaging plates and the subsequent visualization is different from that of radiographic films. The use of metal screens and the selection of the X ray tube voltage as recommended in the film radiography standards are not transferable for Computed Radiography (CR) for weld inspection. The quality of digital radiographs is determined by the inherent unsharpness and the Contrast to Noise Ratio (CNR). Whereas the standard EN 14784-1 describes manageable procedures for the determination of inherent unsharpness and Signal to Noise Ratio (SNR), the rules for the improvement of contrast by selection of the suitable tube voltage and metal screen thickness were not described sufficiently in EN 14874-2. Systematic studies on the influence of copper filter, lead screen imaging plate combinations as well as X-ray tube voltage on the image contrast were performed to improve the image quality for testing of welds with CR systems. Recommendations for the application of metal filter and screen combinations and the selection of appropriate X-ray tube voltages for the imaging plate technique were deduced from these results in order to optimise the X-ray testing procedure of welds. (orig.)

  20. Conception of man in diagnostic radiography research – A discourse analysis of research articles from the journal radiography

    Aim: To analyse discourses of conceptions of man in scientific texts of diagnostic radiography and how these conceptions are constructed in texts. Background: In this article conception of man refers to assumptions researchers have when selecting targets for research, choosing methods and making hypotheses. Method: A discourse analysis is being applied in this article to find discourses in scientific texts on diagnostic radiography. The material consisted of 45 articles from the journal Radiography from February 2009 to August 2013. Findings: Four main discourses were found. They were named technology-centred, patient-centred, doubtful patient and invisible patient discourses. In the technology-centred discourse patients were usually seen as an anonymous group, and they were passive. In the patient-centred discourse patient experiences were often sought and researchers tried to understand patients' emotions, physical abilities and social context. Patients were seen as individuals and active agents. In the doubtful patient discourse patients are not always trusted. In this discourse health care professionals often know better what is for the good of the patient. In the invisible patient discourse patients are invisible to the radiographer/researcher. They are seen merely as body parts, symptoms or diseases

  1. Digital Radiography Reject Analysis: Data Collection Methodology, Results, and Recommendations from an In-depth Investigation at Two Hospitals

    Foos, David H.; Sehnert, W. James; Reiner, Bruce; Siegel, Eliot L.; Segal, Arthur; Waldman, David L.

    2008-01-01

    Reject analysis was performed on 288,000 computed radiography (CR) image records collected from a university hospital (UH) and a large community hospital (CH). Each record contains image information, such as body part and view position, exposure level, technologist identifier, and—if the image was rejected—the reason for rejection. Extensive database filtering was required to ensure the integrity of the reject-rate calculations. The reject rate for CR across all departments and across all exa...

  2. Digital radiography.

    Mattoon, J S

    2006-01-01

    Digital radiography has been used in human medical imaging since the 1980s with recent and rapid acceptance into the veterinary profession. Using advanced image capture and computer technology, radiographic images are viewed on a computer monitor. This is advantageous because radiographic images can be adjusted using dedicated computer software to maximize diagnostic image quality. Digital images can be accessed at computer workstations throughout the hospital, instantly retrieved from computer archives, and transmitted via the internet for consultation or case referral. Digital radiographic data can also be incorporated into a hospital information system, making record keeping an entirely paperless process. Digital image acquisition is faster when compared to conventional screen-film radiography, improving workflow and patient throughput. Digital radiography greatly reduces the need for 'retake' radiographs because of wide latitude in exposure factors. Also eliminated are costs associated with radiographic film and x-ray film development. Computed radiography, charged coupled devices, and flat panel detectors are types of digital radiography systems currently available. PMID:16971994

  3. Dose audit for radiation safety during intravenous urography procedures using computed radiography imaging system

    Dose auditing was done during intravenous urography (IVU) procedure. Eighty patients undergoing IVU examination were included in this study. All investigations were made using a conventional x-ray machine equipped with linear tomography device and images were processed in a Computed Radiography (CR) reader interfaced to a Picture Archival and Communication System (PACS). Thermoluminescent dosimeter was made use of in measurement of radiation dose imparted to patients during IVU procedures. An average of 9.4 radiographs were taken for each IVU procedure and the average effective dose ranged from 0.28 mSv to 7.52 mSv. (author)

  4. Use of computed radiography in respiratory distress syndrome in the neonatal nursery

    A study was performed to establish the value of a computed radiography (CR) system in neonatal respiratory distress syndrome (RDS). CR images obtained with various X-ray doses were compared with the images of a standard film-screen system. The image quality of CR taken with about one half radiation exposure, was comparable to that of the standard high speed film-screen combination. The use of CR could lead to a significant reduction in radiation in the neonatal I.C.U. (orig.)

  5. The use of computed radiography plates to determine light and radiation field coincidence

    Purpose: Photo-stimulable phosphor computed radiography (CR) has characteristics that allow the output to be manipulated by both radiation and optical light. The authors have developed a method that uses these characteristics to carry out radiation field and light field coincidence quality assurance on linear accelerators.Methods: CR detectors from Kodak were used outside their cassettes to measure both radiation and light field edges from a Varian linear accelerator. The CR detector was first exposed to a radiation field and then to a slightly smaller light field. The light impinged on the detector's latent image, removing to an extent the portion exposed to the light field. The detector was then digitally scanned. A MATLAB-based algorithm was developed to automatically analyze the images and determine the edges of the light and radiation fields, the vector between the field centers, and the crosshair center. Radiographic film was also used as a control to confirm the radiation field size.Results: Analysis showed a high degree of repeatability with the proposed method. Results between the proposed method and radiographic film showed excellent agreement of the radiation field. The effect of varying monitor units and light exposure time was tested and found to be very small. Radiation and light field sizes were determined with an uncertainty of less than 1 mm, and light and crosshair centers were determined within 0.1 mm.Conclusions: A new method was developed to digitally determine the radiation and light field size using CR photo-stimulable phosphor plates. The method is quick and reproducible, allowing for the streamlined and robust assessment of light and radiation field coincidence, with no observer interpretation needed

  6. Evaluation of image quality and radiation dose in mammography: a comparison among digital radiography, computed radiography and film-screen systems

    Objective: To compare the image quality, radiation dose and diagnostic accuracy on film-screen, digital radiography (DR) and computed radiography (CR) mammography. Methods: Three different kinds of mammography machines (film-screen, DR and CR) were tested to make sure they were qualified and comparable. Radiographs were taken on Mammo-152 phantom and ACR phantom using film- screen, DR and CR systems with the same radiation dose. Next, radiographs were taken on two phantoms using DR and CR systems with classic mode or AEC and the radiation dose was recorded. The images were numbered and scored by eight independent experienced radiologists under the same reading condition according to ACR method. Statistics was performed with the randomized complete-block design variance analysis. The diagnostic accuracy of three kinds of mammography methods were compared with Kappa test in clinical cases who had pathologic results. Results: The spatial resolution of film-screen system was the highest (7.0-8.0 Lp/mm) and that of CR was the lowest (2.5 Lp/mm). When the radiation dose was increased (27.0%-30.0%), the resolution was improved with DR (+11.0%) but almost no change with CR (+1.5%). The radiation dose of DR was the lowest on ACR phantom. The delineation of mass was better on film-screen than on CR, but the delineation of fibers and speck was better on CR. When the radiation dose of CR was increased (25.0%), the delineation of fibers and speck on CR was similar to that on DR and the delineation of mass was similar to that on film-screen. There was a good correlation between the mammography diagnosis and pathological results (film-screen is 50/56, DR is 83/90 and CR is 61/69, P0.75). The diagnostic accuracy of three mammography systems had no statistical difference [film-screen 89.3% (50/56), DR 92.2% (83/90) and CR 88.4% (61/69 ), Pearson χ2=0.722, P=0.697]. Conclusion: Film/screen system has the highest space resolution and DR has the lowest radiation dose. Three

  7. A comparison of radiography, computed tomography, and magnetic resonance imaging for the diagnosis of palmar process fractures in foals

    The relative sensitivity of radiography, computed tomography, and magnetic resonance imaging for detecting palmar process fractures of the distal phalanx in foals was determined and the imaging findings were compared with histomorphologic evaluations of the palmar processes. Compared to radiography, computed tomography and magnetic resonance imaging did not improve the sensitivity for detection of palmar process fractures. Statistical agreement for palmar process fracture diagnosis was excellent among the three imaging modalities. Histomorphologic evaluations were more sensitive for diagnosis of palmar process fracture than any of the imaging modalities. Three-dimensional image reconstructions and volume measurements of distal phalanges and palmar process fracture fragments from computed tomography studies provided more complete anatomical information than radiography. Magnetic resonance imaging confirmed that the deep digital flexor tendon insertion on the distal phalanx is immediately axial to the site where palmar process fractures occur, and differentiated cartilage, bone, and soft tissue structures of the hoof

  8. Analysis of sculptures using XRF and X-ray radiography

    Calza, C.; Oliveira, D. F.; Freitas, R. P.; Rocha, H. S.; Nascimento, J. R.; Lopes, R. T.

    2015-11-01

    This work reports the analysis of two sacred images on polychrome wood using X-ray Radiography and Energy Dispersive X-Ray Fluorescence. The first case is the analysis of a sculpture portraying Saint Sebastian, the patron saint of Rio de Janeiro, which is considered the second most ancient sacred image of Brazil. This sculpture was made in Portugal and was transported to Brazil by Estácio Sá, founder of the city of Rio de Janeiro, in 1565. Nowadays, it is located on the main altar of the Church of Capuchin Friars. The second case is the analysis of a sculpture representing Our Lady of Conception, which is located in the D. João VI Museum (EBA/UFRJ, Rio de Janeiro). The objective of these analyses was to evaluate the general conditions of the sculptures, identifying possible problems and internal damages, areas that revealed signs of previous retouchings and the materials and pigments employed by the artists, in order to assist its restoration procedures. EDXRF measurements were carried out with a portable system, developed at the Nuclear Instrumentation Laboratory, consisting of a Si-PIN XR-100CR detector from Amptek and an Oxford TF3005 X-ray tube with W anode. An X-ray source, a CR System GE CR50P and IP detectors were used to perform the radiographs. The XRF analysis of the sculptures identified the original pigments in both cases and the radiographic images revealed details of the manufacture; restored regions; extensive use of lead white; presence of cracks on the wood; use of nails and spikes, etc.

  9. Computed radiography as a gamma ray detector—dose response and applications

    O'Keeffe, D. S.; McLeod, R. W.

    2004-08-01

    Computed radiography (CR) can be used for imaging the spatial distribution of photon emissions from radionuclides. Its wide dynamic range and good response to medium energy gamma rays reduces the need for long exposure times. Measurements of small doses can be performed without having to pre-sensitize the computed radiography plates via an x-ray exposure, as required with screen-film systems. Cassette-based Agfa MD30 and Kodak GP25 CR plates were used in applications involving the detection of gamma ray emissions from technetium-99m and iodine-131. Cassette entrance doses as small as 1 µGy (140 keV gamma rays) produce noisy images, but the images are suitable for applications such as the detection of breaks in radiation protection barriers. A consequence of the gamma ray sensitivity of CR plates is the possibility that some nuclear medicine patients may fog their x-rays if the x-ray is taken soon after their radiopharmaceutical injection. The investigation showed that such fogging is likely to be diffuse.

  10. Development of a computer simulation system of intraoral radiography using perspective volume rendering of CT data

    The purpose of this study was to evaluate the usefulness of a computer simulation system for intraoral radiography as an educational aid for radiographic training for dental students. A dried skull was scanned with a multidetector CT, and the series of slice data was transferred to a workstation. A software AVS Express Developer was used to construct the x-ray projected images from the CT slice data. Geometrical reproducibilities were confirmed using numerical phantoms. We simulated images using the perspective projection method with an average value algorithm on this software. Simulated images were compared with conventional film images projected from the same geometrical positions, including eccentric projection. Furthermore, to confirm the changes of the image depending on the projection angles of the x-ray beam, we constructed simulation images in which the root apexes were enhanced with the maximum value algorithm. Using this method, high resolution simulated images with perspective projection, as opposed to parallel, were constructed. Comparing with conventional film images, all major anatomic components could be visualized easily. Any intraoral radiographs at an arbitrary angular projection could be simulated, which was impossible in the conventional training schema for radiographic technique. Therefore, not only standard projected images but also eccentric projections could be displayed. A computer simulation system of intraoral radiography with this method may be useful for training in intraoral radiographic technique for dental students. (author)

  11. The application of the Fuji Computed Radiography system for the diagnosis of pneumoconiosis

    A computer controlled digital system, Fuji Computed Radiography (FCR) is capable of providing more stable output image than conventional screen/film system. So FCR would be an ideal system for the detection of pneumoconiosis due to the constant high quality of the output films. We tried to find the optimum image processing to compensate the small size (1/2 in length of a full-size radiograph) of the output image of digital radiography. The best result for FCR was given with gamma 0.85 and 0.30 enhancement of response at spatial frequency of 0.085 cycle/mm. On the other hand, the digitally processed FCR size ILO standard films, the characteristics of which is different from FCR output films, proved to be most preferable when the image processing is made with gamma 0.85 and 0.25 enhancement at spacial frequency of 0.17 cycle/mm. If the above mentioned image processings are adopted, FCR can be used for the diagnosis of pneumoconiosis with the same accuracy as the conventional film method. (author)

  12. Basilar skull fracture in a Thoroughbred colt: Radiography or computed tomography?

    Chee Kin Lim

    2013-02-01

    Full Text Available A two-year-old Thoroughbred colt was presented to the Equine Clinic, Onderstepoort Veterinary Academic Hospital for head trauma after rearing and falling backwards, hitting his head on the ground. Following medical therapy for acute onset neurological impairment secondary to a suspected basilar skull fracture, the horse was anaesthetised and computed tomography of the skull was performed. A diagnosis of a comminuted basilar skull fracture was made and skull radiographs were taken for comparison. The horse was subsequently euthanased owing to the poor prognosis; necropsy findings were compatible with imaging findings. The value and limitation of computed tomography versus radiography for the diagnosis of basilar skull fracture are discussed in this report.

  13. Comparative study of mesothelioma and asbestosis using computed tomography and conventional chest radiography

    A comparative study using computed tomography and conventional posteroanterior radiography was performed on 27 patients with mesothelioma and 13 patients with advanced asbestosis. The major pathologic features of both asbestosis and mesothelioma were well demonstrated by both modalities; computed tomography demonstrated the findings more frequently and in greater detail. No distinguishing features could be established based on configuration and size of the lesion. Many pleural plaques associated with advanced asbestosis were large and irregular and resembled those associated with mesothelioma. However, nodular involvement of the pleural fissures, pleural effusion, and ipsilateral volume loss with a fixed mediastinum were features predominating in mesothelioma. Growth determination of the plaques associated with asbestosis may be of minimal value since such plaques also undergo growth due to active inflammatory changes

  14. Increasing mobile radiography productivity.

    Wong, Edward; Lung, Ngan Tsz; Ng, Kris; Jeor, Patrick

    2013-01-01

    Mobile radiography using computed radiography (CR) cassettes is a common equipment combination with a workflow bottleneck limited by location of CR readers. Advent of direct digital radiography (DDR) mobile x-ray machines removes this limitation by immediate image review and quality control. Through the use of key performance indicators (KPIs), the increase in efficiency can be quantified. PMID:23986937

  15. Digital vs conventional radiography: cost and revenue analysis

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

  16. Dose reduction using non lineal diffusion and smoothing filters in computed radiography

    The use of Computed Radiography (CR) into clinical practice has been followed by a high increase in the number of examinations performed and overdose cases in patients, especially children in pediatric applications. Computed radiographic images are corrupted by noise because either data acquisition or data transmission. The level of this inherent noise is related with the X-ray dose exposure: lower radiation exposure involves higher noise level. The main aim of this work is to reduce the noise present in a low radiation dose CR image in order to the get a CR image of the same quality as a higher radiation exposure image. In this work, we use a non lineal diffusion filtering method to reduce the noise level in a CR, this means that we are able to reduce the exposure, milliampere-second (mAs), and the dose absorbed by the patients. In order to get an optimal result, the diffusive filter is complemented with a smoothing filter with edge detection in order to preserve edges. Therefore, the proposed method consists in obtaining a good quality CR image for diagnostic purposes by selection of lower X-ray exposure jointly with a reduction of the noise. We conclude that a good solution to minimize the dose to patients, especially children in pediatric applications, in X-ray computed radiography consists in decreasing the mAs of the X-ray exposure and then processing the image with the proposed method. - Highlights: • We have investigated the techniques to obtain the image quality to make a confident diagnosis. • We have used diffusion and smoothing filter in order to reduce the exposure. • Reducing CR doses, especially in pediatric applications. • The new CR images allow medical researchers to analyze how low dose affects the patient diagnosis

  17. Detection of bone erosions in rheumatoid arthritis wrist joints with magnetic resonance imaging, computed tomography and radiography

    Døhn, Uffe Møller; Ejbjerg, Bo J; Hasselquist, Maria;

    2008-01-01

    BACKGROUND: The objectives of the present study were, with multidetector computed tomography (CT) as the reference method, to determine the performance of magnetic resonance imaging (MRI) and radiography for the detection of bone erosions in rheumatoid arthritis wrist bones, and to test whether...... measuring volumes of erosions on CT and MRI is reproducible and correlated to semiquantitative assessments (scores) of erosions on CT, MRI and radiography. METHODS: Seventeen patients with rheumatoid arthritis and four healthy control individuals underwent CT, MRI and radiography of one wrist, performed on...... the same day. CT was performed on a Philips Mx8000IDT unit (voxel size 0.4 mm x 0.4 mm x 1 mm) and MRI was performed on a Philips Panorama 0.6T unit (voxel size 0.4 mm x 0.4 mm x 0.4 mm). Images were evaluated separately for erosions in all wrist bones and were scored according to the principles of...

  18. Analysis of the potential of crack detection by neutron radiography

    The principle is explained of nondestructive crack detection using neutrons. A survey is presented of sources, principles of moderation and collimation; the interaction is explained of neutrons with matter and methods of detection. The method of neutron radiography is used for inspecting fuel in nuclear power plants, for the detection of corrosion and water in aviation, crack detection of special alloys, in the chemical industry, engineering, testing of printed circuits in electronics, dosemeter calibration, etc. (M.D.). 2 figs, 1 tab

  19. Computer-aided diagnosis of pulmonary diseases using x-ray darkfield radiography

    In this work we develop a computer-aided diagnosis (CAD) scheme for classification of pulmonary disease for grating-based x-ray radiography. In addition to conventional transmission radiography, the grating-based technique provides a dark-field imaging modality, which utilizes the scattering properties of the x-rays. This modality has shown great potential for diagnosing early stage emphysema and fibrosis in mouse lungs in vivo. The CAD scheme is developed to assist radiologists and other medical experts to develop new diagnostic methods when evaluating grating-based images. The scheme consists of three stages: (i) automatic lung segmentation; (ii) feature extraction from lung shape and dark-field image intensities; (iii) classification between healthy, emphysema and fibrosis lungs. A study of 102 mice was conducted with 34 healthy, 52 emphysema and 16 fibrosis subjects. Each image was manually annotated to build an experimental dataset. System performance was assessed by: (i) determining the quality of the segmentations; (ii) validating emphysema and fibrosis recognition by a linear support vector machine using leave-one-out cross-validation. In terms of segmentation quality, we obtained an overlap percentage (Ω) 92.63  ±  3.65%, Dice Similarity Coefficient (DSC) 89.74  ±  8.84% and Jaccard Similarity Coefficient 82.39  ±  12.62%. For classification, the accuracy, sensitivity and specificity of diseased lung recognition was 100%. Classification between emphysema and fibrosis resulted in an accuracy of 93%, whilst the sensitivity was 94% and specificity 88%. In addition to the automatic classification of lungs, deviation maps created by the CAD scheme provide a visual aid for medical experts to further assess the severity of pulmonary disease in the lung, and highlights regions affected. (paper)

  20. Computer-aided diagnosis of pulmonary diseases using x-ray darkfield radiography

    Einarsdóttir, Hildur; Yaroshenko, Andre; Velroyen, Astrid; Bech, Martin; Hellbach, Katharina; Auweter, Sigrid; Yildirim, Önder; Meinel, Felix G.; Eickelberg, Oliver; Reiser, Maximilian; Larsen, Rasmus; Kjær Ersbøll, Bjarne; Pfeiffer, Franz

    2015-12-01

    In this work we develop a computer-aided diagnosis (CAD) scheme for classification of pulmonary disease for grating-based x-ray radiography. In addition to conventional transmission radiography, the grating-based technique provides a dark-field imaging modality, which utilizes the scattering properties of the x-rays. This modality has shown great potential for diagnosing early stage emphysema and fibrosis in mouse lungs in vivo. The CAD scheme is developed to assist radiologists and other medical experts to develop new diagnostic methods when evaluating grating-based images. The scheme consists of three stages: (i) automatic lung segmentation; (ii) feature extraction from lung shape and dark-field image intensities; (iii) classification between healthy, emphysema and fibrosis lungs. A study of 102 mice was conducted with 34 healthy, 52 emphysema and 16 fibrosis subjects. Each image was manually annotated to build an experimental dataset. System performance was assessed by: (i) determining the quality of the segmentations; (ii) validating emphysema and fibrosis recognition by a linear support vector machine using leave-one-out cross-validation. In terms of segmentation quality, we obtained an overlap percentage (Ω) 92.63  ±  3.65%, Dice Similarity Coefficient (DSC) 89.74  ±  8.84% and Jaccard Similarity Coefficient 82.39  ±  12.62%. For classification, the accuracy, sensitivity and specificity of diseased lung recognition was 100%. Classification between emphysema and fibrosis resulted in an accuracy of 93%, whilst the sensitivity was 94% and specificity 88%. In addition to the automatic classification of lungs, deviation maps created by the CAD scheme provide a visual aid for medical experts to further assess the severity of pulmonary disease in the lung, and highlights regions affected.

  1. Initial quality performance results using a phantom to simulate chest computed radiography

    Muhogora Wilbroad

    2011-01-01

    Full Text Available The aim of this study was to develop a homemade phantom for quantitative quality control in chest computed radiography (CR. The phantom was constructed from copper, aluminium, and polymenthylmethacrylate (PMMA plates as well as Styrofoam materials. Depending on combinations, the literature suggests that these materials can simulate the attenuation and scattering characteristics of lung, heart, and mediastinum. The lung, heart, and mediastinum regions were simulated by 10 mm x 10 mm x 0.5 mm, 10 mm x 10 mm x 0.5 mm and 10 mm x 10 mm x 1 mm copper plates, respectively. A test object of 100 mm x 100 mm and 0.2 mm thick copper was positioned to each region for CNR measurements. The phantom was exposed to x-rays generated by different tube potentials that covered settings in clinical use: 110-120 kVp (HVL=4.26-4.66 mm Al at a source image distance (SID of 180 cm. An approach similar to the recommended method in digital mammography was applied to determine the CNR values of phantom images produced by a Kodak CR 850A system with post-processing turned off. Subjective contrast-detail studies were also carried out by using images of Leeds TOR CDR test object acquired under similar exposure conditions as during CNR measurements. For clinical kVp conditions relevant to chest radiography, the CNR was highest over 90-100 kVp range. The CNR data correlated with the results of contrast detail observations. The values of clinical tube potentials at which CNR is the highest are regarded to be optimal kVp settings. The simplicity in phantom construction can offer easy implementation of related quality control program.

  2. Comparison of diagnostic accuracy of root perforation, external resorption and fractures using cone-beam computed tomography, panoramic radiography and conventional & digital periapical radiography

    Wilton Mitsunari Takeshita

    2015-01-01

    Conclusions: CBCT showed the best results in the diagnosis of ERR and VRF. The diagnosis of ERR was the least accurate, panoramic radiography being not appropriate for its diagnosis. CBCT and conventional periapical radiography obtained similar results for the evaluation of RP. So for, RP indicate the conventional periapical radiography because CBCT has a higher radiation dose.

  3. The effect of radiation dose reduction on clinical image quality in chest radiography of premature neonates using a dual-side readout technique computed radiography system

    The purpose of the present study was to investigate if the exposure could be reduced from the clinical setting (resulting in an effective dose of 8 μSv for a neonate of weight 0.7 kg and height 25 cm at a tube voltage of 90 kV) without negatively influencing the image quality for a dual-side readout technique computed radiography (CR) system in chest radiography of premature neonates. Chest radiographs of premature neonates were acquired with the double-side readout technique CR system. The images underwent simulated dose reduction in steps of 20% to represent five different radiation dose levels. Four image quality criteria, related to the visibility of important anatomical structures, were used in a visual grading study where five experienced radiologists rated how well the criteria were fulfilled for all images. When reducing the radiation dose, a decrease in image quality could be observed already at the 80% dose level for all the structures. The results indicate that a decrease in exposure from the clinically used setting affects the image quality negatively for the CR system. (authors)

  4. Combined photon-neutron radiography for nondestructive analysis of materials

    Combined photon-neutron radiography was investigated as a nondestructive method to determine the shape and material composition of complex objects. A system consisting of photon and neutron sources in a cone beam configuration and a 2D detector array was modeled using the MCNP5 code. Photon-to-neutron transmission ratios were determined for a car engine using 0.1, 0.5, 2.5 MeV neutrons and 0.2, 0.5, 1 MeV photons. Focusing on inherent difference between neutron and photon interactions with matter, it was possible to classify materials within the scanned object. (author)

  5. Development of automatic analyses for star-shot images using computed radiography (CR)

    Recent progress in radiation therapy has been greatly enhanced in many facilities by the development of new machines for treatment, improved computer technology for radiotherapy treatment planning systems (RTPs), increased accuracy of radiation therapy such as stereotactic irradiation, and intensity-modulated radiation therapy (IMRT). Quality control (QC) of the isocenter, which has consisted of gantry rotation and limiting the radiation field, is important for greater accuracy of these radiation therapy technologies. Star-shot analyses using computed radiography (CR) for evaluation of the isocenter were employed in this study. Devices to support CR were created, and a method of automatically analyzing images obtained by the star-shot technique, which calculated the error (distance) from the isocenter and the incident beam angle, were developed. In terms of the accuracy of our method, the average maximum error was 0.33 mm (less than 2 pixels: 0.35 mm), the average absolute error and incident beam angle errors were 0.3 mm and 0.4 degrees at maximum and at one standard deviation (SD), respectively. In this study, the processing times were 16 sec at minimum, 152 sec at maximum, 18 sec at most frequencies, and 23.6 sec on average. In conclusion, it was considered that our newly developed method for analyzing star-shot images using CR enabled immediate, quantitative evaluation of the isocenter. (author)

  6. Influence of estrogen deficiency and tibolone therapy on trabecular and cortical bone evaluated by computed radiography system in rats

    Carvalho, Ana Carolina Bergmann de; Henriques, Helene Nara [Postgraduate Program in Pathology, Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Fernandes, Gustavo Vieira Oliveira [Postgraduate Program in Medical Sciences, Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Lima, Inaya; Oliveira, Davi Ferreira de; Lopes, Ricardo Tadeu [Nuclear Engineering Program, Federal University of Rio de Janeiro (UFRJ), RJ (Brazil); Pantaleao, Jose Augusto Soares [Maternal and Child Department, Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Granjeiro, Jose Mauro [Department of Cellular and Molecular Biology, Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Silva, Maria Angelica Guzman [Department of Pathology, Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil)

    2012-03-15

    Purpose: To verify the effects of tibolone administration on trabecular and cortical bone of ovariectomized female rats by computed radiography system (CRS). Methods: The experiment was performed on two groups of rats previously ovariectomized, one received tibolone (OVX+T) while the other did not (OVX), those groups were compared to a control group (C) not ovariectomized. Tibolone administration (1 mg/day) began thirty days after the ovariectomy and the treatment remained for five months. At last, the animals were euthanized and femurs and tibias collected. Computed radiographs of the bones were obtained and the digital images were used to determine the bone optical density and cortical thickness on every group. All results were statistically evaluated with significance set at P<0.05%. Results: Tibolone administration was shown to be beneficial only in the densitometric analysis of the femoral head, performing higher optical density compared to OVX. No difference was found in cortical bone thickness. Conclusion: Ovariectomy caused bone loss in the analyzed regions and tibolone administered in high doses over a long period showed not to be fully beneficial, but preserved bone mass in the femoral head. (author)

  7. Influence of estrogen deficiency and tibolone therapy on trabecular and cortical bone evaluated by computed radiography system in rats

    Purpose: To verify the effects of tibolone administration on trabecular and cortical bone of ovariectomized female rats by computed radiography system (CRS). Methods: The experiment was performed on two groups of rats previously ovariectomized, one received tibolone (OVX+T) while the other did not (OVX), those groups were compared to a control group (C) not ovariectomized. Tibolone administration (1 mg/day) began thirty days after the ovariectomy and the treatment remained for five months. At last, the animals were euthanized and femurs and tibias collected. Computed radiographs of the bones were obtained and the digital images were used to determine the bone optical density and cortical thickness on every group. All results were statistically evaluated with significance set at P<0.05%. Results: Tibolone administration was shown to be beneficial only in the densitometric analysis of the femoral head, performing higher optical density compared to OVX. No difference was found in cortical bone thickness. Conclusion: Ovariectomy caused bone loss in the analyzed regions and tibolone administered in high doses over a long period showed not to be fully beneficial, but preserved bone mass in the femoral head. (author)

  8. Radiography - A new field among health sciences in Finland

    In order to secure high quality X-ray services and efficient operation of clinical radiography, a study programme in radiography science was implemented at the University of Oulu in 1999. The need for a specific field of science has emerged as a result of social changes, such as the aging population, and the fast development of technology that has caused significant changes in the radiological working environment and clinical radiography. A need for a new, research-based informational foundation of clinical radiography is the basis for the programme. As service producers, radiographers need vast knowledge as well as specific expertise. The research object of radiography science is clinical radiography. If it was studied from the viewpoint of other sciences, the key professional skills of a radiographer would remain unexplored. Implementing an own field of science has enabled the development of radiography from its own bases. Basic research in the field is represented, for example, by the concept analysis of radiography in health sciences. Radiography science should produce research results for both clinical radiography and the instruction of radiography. So far, research results have dealt with the professional decision-making of a radiographer, the influences of computer technology on a radiographer's work and measuring the radiation exposure of a population

  9. Radiologic analysis of femoral acetabular impingement: from radiography to MRI

    Dwek, Jerry R. [University of California at San Diego, Department of Radiology, Rady Children' s Hospital and Health Center, San Diego, CA (United States); San Diego Imaging, San Diego, CA (United States); Monazzam, Shafagh [Rady Children' s Hospital and Health Center, Department of Orthopedics, San Diego, CA (United States); Chung, Christine B. [University of California at San Diego, Department of Radiology, San Diego, CA (United States)

    2013-03-15

    Femoral acetabular impingement is a set of morphologic abnormalities that are considered to be a major cause of degenerative disease in the hip joint. Early changes are already present in adolescence when it is the pediatric radiologist who must assess current damage with the aim of averting progression to more severe and debilitating osteoarthritis. A multimodality approach is used for diagnosis, that includes conventional radiography and CT to assess the osseous structures. MR arthrography is the primary advanced imaging modality for assessment of morphologic changes as well as injuries of the labrum and articular cartilage. Details of radiologic imaging are offered to guide the radiologist and provide an avenue for the accurate description of the osseous and articular alterations and injury. (orig.)

  10. Evaluation of a computed radiography system for megavoltage photon beam dosimetry

    Computed radiography (CR) systems have been gaining adoption as digital replacements for film for diagnostic and therapy imaging. As a result, film processors are being removed from service, leaving a void for the medical physicists who use film and processors for two-dimensional megavoltage beam dosimetry. This is the first report to evaluate the ability of a commercial CR reader and storage phosphor plate system to accurately quantitate absolute dose and dose distributions from a 6 MV photon beam. There are potential advantages and disadvantages of current CR systems compared to film systems. CR systems inherently produce a linear dose-response over several logs of dose. However, the barium in the storage phosphor has a higher atomic number than the silver in film, resulting in significant energy sensitivity. The purpose of this work is to fully characterize the impact of these and other features of this CR system relevant to dosimetry. The tests performed and reported on in this study include uniformity of readout across a uniform field, geometrical accuracy, intra- and interday reproducibility, signal decay with time and with light exposure, dose-to-signal calibration, high dose effects, obliquity effects, perpendicular and parallel calibration results, field size and depth of measurement effects and the use of lead filters to minimize them, and intensity modulated radiation therapy quality assurance test results compared to that for film. Practical techniques are provided to optimize the accuracy of the system as a dosimetric replacement for film

  11. Comparison of low-contrast detectability of computed radiography and screen/ film mammography systems

    The objective of this study is to compare low-contrast detectability of computed radiography (CR) and screen/ film (SF) mammography systems. The Nijimegen contrast detail test object (CDMAM type 3.4) was imaged at 28 kV, in automatic exposure control mode separately. Six medical imaging physicists read each CDMAM phantom image. Contrast detail curves were plotted to compare low-contrast detectability of CR (soft copy and hard copy) and SF mammography systems. Effect of varying exposure parameters, namely kV, object position inside the breast phantom, and entrance surface exposure (ESE) on the contrast detail curve were also investigated using soft copy CR. The significance of the difference in contrast between CR and SF, and for each exposure parameter, was tested using non-parametric Kruskal-Wallis test. The low-contrast detectability of the CR (soft copy and hard copy) system was found to be not significantly different to that of the SF system (p> 0.05, Kruskal-Wallis test).For CR soft copy, no significant relationship (p>0.05, Kruskal-Wallis test) was seen for variation of kV, object position inside the breast phantom and ESE. This indicates that CR is comparable with SF for useful detection and visualization of low-contrast objects such as small low-contrast areas corresponding to breast pathology. (Author)

  12. Patient dose, gray level and exposure index with a computed radiography system

    Silva, T. R.; Yoshimura, E. M.

    2014-02-01

    Computed radiography (CR) is gradually replacing conventional screen-film system in Brazil. To assess image quality, manufactures provide the calculation of an exposure index through the acquisition software of the CR system. The objective of this study is to verify if the CR image can be used as an evaluator of patient absorbed dose too, through a relationship between the entrance skin dose and the exposure index or the gray level values obtained in the image. The CR system used for this study (Agfa model 30-X with NX acquisition software) calculates an exposure index called Log of the Median (lgM), related to the absorbed dose to the IP. The lgM value depends on the average gray level (called Scan Average Level (SAL)) of the segmented pixel value histogram of the whole image. A Rando male phantom was used to simulate a human body (chest and head), and was irradiated with an X-ray equipment, using usual radiologic techniques for chest exams. Thermoluminescent dosimeters (LiF, TLD100) were used to evaluate entrance skin dose and exit dose. The results showed a logarithm relation between entrance dose and SAL in the image center, regardless of the beam filtration. The exposure index varies linearly with the entrance dose, but the angular coefficient is beam quality dependent. We conclude that, with an adequate calibration, the CR system can be used to evaluate the patient absorbed dose.

  13. Evaluation of entrance surface air kerma from exposure index in computed radiography

    Costa, A. M.; Pelegrino, M. S.

    2014-11-01

    The aim of this study was to establish an indirect method to calculate the values of entrance surface air kerma in patients undergoing diagnostic examinations in X-ray systems with computed radiography based on the exposure index. The entrance surface air kerma values were compared with values obtained also indirectly based on measurements of X-ray tube output. The mean±standard deviation (1σ) and third quartile for entrance surface air kerma calculated from the exposure index were 2.1±1.0 mGy and 3.0 mGy, respectively. For entrance surface air kerma based on measurements of the X-ray tube output, the mean±standard deviation (1σ) and third quartile were respectively 3.1±1.9 mGy and 5.5 mGy. The observed values of entrance surface air kerma are smaller than the reference level adopted in Brazil (10 mGy). The results obtained with both methods were similar when taking into account the estimated uncertainties in the determination of air kerma values, although the reproducibility of the determinations based on the exposure index is better.

  14. Characterization of a computed radiography system for external radiotherapy beam dosimetry

    Aberle, Christoph; Kapsch, Ralf-Peter

    2016-06-01

    A commercial computed radiography (CR) system was studied as an option for quantitative dosimetry quality assurance of external radiotherapy beams. Following the examination of influencing quantities, practical measurement procedures are discussed. Corrections were derived for image fading, an observed long-term response drift and the image length scale, which was found to be off by up to 2–3%. It is known that energy dependence is important for CR measurements. Therefore, signal-to-dose calibration curves and the energy dependence of the response were studied extensively using multiple photon and electron beam qualities. Doses which yield the same signal vary by up to tens of percent for different beam qualities. Results on the directional response of the plates are presented. It was found that rotations of up to 30° to 40° relative to perpendicular irradiation yield no significant change in response. Finally, the homogeneity of the response over the measurement region was studied for electrons and photons and a correction method is described. In summary, relative dose measurements with uncertainties of a few percent are feasible in regions of constant beam energy.

  15. Comparison of full field digital (FFD) and computed radiography (CR) mammography systems in Greece.

    Kalathaki, M; Hourdakis, C J; Economides, S; Tritakis, P; Kalyvas, N; Simantirakis, G; Manousaridis, G; Kaisas, I; Kamenopoulou, V

    2011-09-01

    The purpose of this study is to evaluate and compare the performance of 52 full field digital (FFD) and computed radiography (CR) mammography systems checked by the Greek Atomic Energy Commission with respect to dose and image quality. Entrance surface air kerma (ESAK) was measured and average glandular dose (AGD) was calculated according to the European protocol on dosimetry in mammography. The exposures were performed using the clinical protocol of each laboratory. The image quality was assessed by the total score of resolved phantom structures incorporated in an American College of Radiology accreditation phantom. The mean ESAK values for FFD and CR systems were 4.59 ± 1.93 and 5.0 ± 1.78 mGy, respectively, whereas the AGD yielded a mean value of 1.06 ± 0.36 mGy for the FFD and 1.04 ± 0.35 mGy for the CR systems. Considering image quality, FFD systems indicated a mean total score of 13.04 ± 0.89, whereas CR systems a mean total score of 11.54 ± 1.06. PMID:21821614

  16. A software tool for quality assurance of computed/digital radiography (CR/DR) systems

    Desai, Nikunj; Valentino, Daniel J.

    2011-03-01

    The recommended methods to test the performance of computed radiography (CR) systems have been established by The American Association of Physicists in Medicine, Report No. 93, "Acceptance Testing and Quality Control of Photostimulable Storage Phosphor Imaging Systems". The quality assurance tests are categorized by how frequently they need to be performed. Quality assurance of CR systems is the responsibility of the facility that performs the exam and is governed by the state in which the facility is located. For Example, the New York State Department of Health has established a guide which lists the tests that a CR facility must perform for quality assurance. This study aims at educating the reader about the new quality assurance requirements defined by the state. It further demonstrates an easy to use software tool, henceforth referred to as the Digital Physicist, developed to aid a radiologic facility in conforming with state guidelines and monitoring quality assurance of CR/DR imaging systems. The Digital Physicist provides a vendor independent procedure for quality assurance of CR/DR systems. Further it, generates a PDF report with a brief description of these tests and the obtained results.

  17. Visualisation of uric acid renal calculi (UARC) using computed radiography (CR)

    Aim: To investigate the capability of CR to visualise UARC through inverse image post-processing technique. Methods. A patient-equivalent phantom (PEP) consisting of six 2.5-cm thick Perspex layers and one 1-mm thick aluminium layer was used to represent human tissues and bones respectively. A total of eight exposures were made on PEP to radiograph 1 mm, 2 mm and 3 mm UARC located between three layers of 2-cm thick cattle muscle, positioned inside the PEP. After each exposure, a layer of Perspex was removed, and another exposure was made until only one Perspex layer and one layer of muscle (containing the three UARC) remained. For each exposure, two images (a positive and an inverse image) were produced for comparison using Fuji XG1 computed radiography system with IP0 type C-ST-VI Fuji imaging plate (equivalent to 400 speed radiographic screen-film systems). Results: In positive image, UARC of all three sizes (1 mm, 2 mm and 3 mm) located in the cattle muscle, cannot be visualised when the PEP consists of more than one layer of Perspex. In inverse image, the 3-mm UARC can be seen even when the PEP consists of five layers of Perspex. Conclusion: This study revealed the post-processing capability of CR to increase the visualisation of UARC which has been categorised as radiolucent. A further study of clinical image quality should be performed using blinded observers to test diagnostic accuracy, which was not included in this study.

  18. Analysis of physeal growth in dogs, using biplanar radiography

    Biplanar radiography was used to study normal growth of the left and right radius in 5 Beagles and growth of the left radius alone in 15 additional Beagles. We explored the applicability of this radiographic method in veterinary medicine by measuring the contribution to total radius length from each growth plate. Spherical tantalum markers (0.5 mm) were embedded in the proximal epiphysis, diaphysis, and distal epiphysis of each dog's radius at 10 weeks of age. Simultaneous biplanar radiographic views were obtained every 4 weeks until skeletal maturity was documented. A three-dimensional coordinate system was constructed allowing for measurement of growth (in millimeters). Resolution of the measuring system was 0.074 mm. Mean +/- SEM length of the skeletally mature Beagle's radius, as measured from proximal epiphyseal bead to distal epiphyseal bead, was 95.33 +/- 1.07 mm. The percentage of contribution to the total radius length from the proximal and distal growth plates was 36.76 and 64.73%, respectively, with 95% confidence interval of 2.29%. The percentage of contribution to radius length from the distal radial growth plate increased for each consecutive time segment, with the distal radial physis contributing 61.75% from 10 to 14 weeks of age and increasing to 70.22% from 22 to 26 weeks of age. Significant growth was not observed after 26 weeks of age. The period of most rapid growth was between 10 and 14 weeks of age. Biplanar radiography was accurate and precise in quantifying the relative contribution of the proximal and distal growth plate to radius length in Beagles. The method is applicable in veterinary research or clinical medicine for monitoring of axial and angular growth: physiologic, iatrogenic, or pathologic

  19. AP versus PA positioning in lumbar spine computed radiography: Image quality and individual organ doses

    Purpose: Radiological imaging examinations must be optimised in order to ensure that the radiation dose is kept as low as reasonably possible (ALARP). The aim of this study was to compare anteroposterior (AP) and posteroanterior (PA) projections of the lumbar spine, at various kVp increments, in order to establish optimum parameters. Methods: An anthropomorphic phantom was imaged in both the AP/PA projections and at various kVp increments. Acquisitions were undertaken using a Wolverson Acroma X-ray unit and processed using an Agfa computed radiography (CR) unit. The entrance surface dose was recorded and converted to effective and organ doses using PCXMC 2.0 software. Five observers were then asked to evaluate the images, using a two-alternative force choice (2AFC) approach and a scale based on EC guidelines. Results: The PA projection lowered the mean effective dose by 19.8% and also the mean absorbed dose to the stomach (70.4%), colon (61.1%), remainder tissues (33.2%), ovaries (7.3%) and testes (15.9%). However, this was at the expense of slightly inferior image quality, not statistically significant. For AP projections, a higher kVp is a further option for dose reduction. Conclusion: Dose optimisation requires the production of an image that is acceptable for the purpose intended. Based on ALARP, and when taking into consideration the dose reductions in this study, it may now be time to routinely use PA projections when imaging the lumbar spine. The use of a higher kVp should also be considered as an option but would be more useful for AP projections. - Highlights: • We compared AP and PA projections for lumbar spine radiography when using CR. • Switching from an AP to a PA projection reduces the radiation dose. • Effective dose and organ dose can be lowered by moving to a PA projection. • Slight reductions in image quality were demonstrated for PA projections. • Higher kVps lower the radiation dose but reduce image quality

  20. A comparative study of computed radiography-based mammography using digital phosphor storage plate and full field digital mammography

    Kanaga Kumari Chelliah

    2013-01-01

    Full Text Available Background: Two digital mammography systems, based on different physical concepts, have been introduced in the last few years namely the full-field digital mammography (FFDM system and computed radiography-based mammography using digital storage phosphor plate (DSPM. Aims: The objective of this study was to compare the image quality for DSPM and FFDM using a grading scale based on previously published articles. Materials and Methods: This comparative diagnostic study was done for 5-month duration at the Breast Clinic. The system used was the Lorad Selenia FFDM system and the Mammomat 3000 Nova DSPM system. The craniocaudal and mediolateral oblique projections were done on both breast on 58 asymptomatic women using both DSPM and FFDM. The mammograms were evaluated for eight criteria of image quality: Tissue coverage, compression, exposure, contrast, resolution, noise, artifact, and sharpness by two independent radiologists. Statistical Analysis: Wilcoxon Signed Rank Test and Weighted Kappa. Results: FFDM was rated significantly better (P < 0.05 for five aspects: Tissue coverage, compression, contrast, exposure, and resolution and equal to DSPM for sharpness, noise, and artifact. Conclusion: FFDM was superior in five aspects and equal to DSPM for three aspects of image quality.

  1. Computed tomographic analysis of urinary calculi

    Newhouse, J.H.; Prien, E.L.; Amis, E.S. Jr.; Dretler, S.P.; Pfister, R.C.

    1984-03-01

    Excised urinary calculi were subjected to computed tomographic (CT) scanning in an attempt to determine whether CT attenuation values would allow accurate analysis of stone composition. The mean, maximum, and modal pixel densities of the calculi were recorded and compared; the resulting values reflected considerable heterogeneity in stone density. Although uric acid and cystine calculi could be identified by their discrete ranges on one or more of these criteria, calcium-containing stones of various compositions, including struvite, could not be distinguished reliably. CT analysis of stone density is not likely to be more accurate than standard radiography in characterizing stone composition in vivo.

  2. Comparative Reject Analysis in Conventional Film-screen and Digital Storage Phosphor Radiography

    The purpose of this work was to gather information about the benefits in patient care caused by the introduction of digital radiography. In particular, the possibility of reducing the number of image repeats and thus unnecessary patient radiation was sought. Waste films of conventional radiography were collected - in digital radiography each image delete command at the post-processing workstation was documented. Rejected images were analysed retrospectively. The overall reject rate was 27.6% in the conventional and 2.3% in the digital department. While in the conventional department the main reason for rejection was 'exposure' and 'others' (i.e. problems related to film handling), the main reason in the digital environment was 'positioning'. Reject analysis yields representative data about the current performance of a radiology department. A marked reduction of repeated X rays and consequently reduced radiation exposure of the patient was clearly shown in this study comparing two differently working radiology departments. This is one of several benefits of digital radiography in patient care. (author)

  3. Experimental study of the X-ray spectra optimization for computed radiography mammography systems

    Digital mammography is replacing screen-film mammography due to several advantages of digital receptors. The use of Computed Radiography (CR) mammography systems has been considered an alternative to achieve digital images with a low cost. Besides, the optimization of the X-ray spectrum, characterized by the anode/filter combination and tube potential, is an important step in order to improve the image quality with the lower dose to the breast. In this work, we investigated the optimal X-ray spectra using a figure of merit for two mammography equipment: Senographe DMR (General Electric Medical Systems) and Mammomat 3000 Nova (Siemens), both using an image plate Kodak EHR-M2 (Kodak DirectView). A PMMA phantom, simulating breast with thicknesses of 5 cm, was used. The anode/filter combinations evaluated were: Mo/Mo, Mo/Rh, Rh/Rh and Rh/Al for the Senographe system, and Mo/Mo, Mo/Rh, W/Rh for the Mammomat system, for all the intervals of tube potential range from 24 to 35 kVp. Results demonstrate that the higher values of FOM were achieved with the Rh/Rh at 29 kVp and Rh/Al at 26 kVp for the Senographe system, and for the W/Rh at 28 kVp in the Mammomat one. The reduction in the dose associated with the optimum spectra was 13 and 26% for the Senographe and Mammomat systems, respectively. Finally, our results suggest that anode/filter combinations of more energetic spectra than the standard Mo/Mo combination are recommended for thicker breast, in order to reduce the breast dose levels. (author)

  4. Extremity exams optimization for computed radiography; Otimizacao de exames de extremidade para radiologia computadorizada

    Pavan, Ana Luiza M.; Alves, Allan Felipe F.; Velo, Alexandre F.; Miranda, Jose Ricardo A., E-mail: analuiza@ibb.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Instituto de Biociencias. Departamento de Fisica e Biofisica; Pina, Diana R. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Faculdade de Medicina. Departamento de Doencas Tropicais e Diagnostico por Imagem

    2013-08-15

    The computed radiography (CR) has become the most used device for image acquisition, since its introduction in the 80s. The detection and early diagnosis, obtained through CR examinations, are important for the successful treatment of diseases of the hand. However, the norms used for optimization of these images are based on international protocols. Therefore, it is necessary to determine letters of radiographic techniques for CR system, which provides a safe medical diagnosis, with doses as low as reasonably achievable. The objective of this work is to develop an extremity homogeneous phantom to be used in the calibration process of radiographic techniques. In the construction process of the simulator, it has been developed a tissues' algorithm quantifier using Matlab®. In this process the average thickness was quantified from bone and soft tissues in the region of the hand of an anthropomorphic simulator as well as the simulators' material thickness corresponding (aluminum and Lucite) using technique of mask application and removal Gaussian histogram corresponding to tissues of interest. The homogeneous phantom was used to calibrate the x-ray beam. The techniques were implemented in a calibrated hand anthropomorphic phantom. The images were evaluated by specialists in radiology by the method of VGA. Skin entrance surface doses were estimated (SED) corresponding to each technique obtained with their respective tube charge. The thicknesses of simulators materials that constitute the homogeneous phantom determined in this study were 19.01 mm of acrylic and 0.81 mm of aluminum. A better picture quality with doses as low as reasonably achievable decreased dose and tube charge around 53.35% and 37.78% respectively, compared normally used by radiology diagnostic routine clinical of HCFMB-UNESP. (author)

  5. Cause analysis of missing diagnosis for vertebral fracture on lateral chest radiography

    Objective: To analyze the cause of missing diagnosis for vertebral fracture on lateral chest radiography. Methods: Lateral chest radiographies of 1638 hospitalized patients (871 males and 767 females) were retrospectively reviewed for identifying vertebral fractures. Their ages ranged from 50 to 91 years with the mean of 63.5 years. Complains and application for chest radiography in all patients were not related to osteoporosis and vertebral fracture. Vertebral fracture and fracture severity were evaluated using Genant's semiquantitative visual method, taking approximately a 20%-25% vertebral height reduction as mild grade, 26%--40% as moderate grade and 41% or greater as severe grade. Evaluation results of the vertebral fracture, original X-ray reports, as well as medical records were compared for further analysis. Results: Eighty-four in 1638 patients showed vertebral fractures on the lateral chest radiographies. Of them, vertebral fractures were reported in 30 cases and 54 patients were not reported on their original X-ray reports. There were 63 vertebral fractures in 54 un-reported patients, most of which were single fracture (75% or 47/63). Grade I fracture accounted for 54% (34/63), Grade II fracture 33% (21/63), while 13% presented grade III fracture (8/63). In all 84 patients with vertebral fractures, only 5 cases (6%) underwent dual energy X-ray absorptiometry (DXA) measurement, 5 cases (6%) were recorded to have vertebral fractures on the medical papers, as well as 15 cases (18%) were prescribed drugs related to the osteoporosis when discharged from hospital. All drugs prescribed for the 15 patients were limited only to calcium. Conclusions: More attention should be paid to osteoporosis by doctors including radiologists. Vertebral fracture on lateral chest radiography should be completely diagnosed, which is helpful for both prevention and treatment. (authors)

  6. An in vitro comparison of diagnostic abilities of conventional radiography, storage phosphor, and cone beam computed tomography to determine occlusal and approximal caries

    Kayipmaz, Saadettin, E-mail: kayipmaz@ktu.edu.tr [Karadeniz Technical University, Faculty of Dentistry, Department of Oral Diagnosis and Radiology, Farabi, 61080 Trabzon (Turkey); Sezgin, Omer Said, E-mail: omersaidsezgin@gmail.com [Karadeniz Technical University, Faculty of Dentistry, Department of Oral Diagnosis and Radiology, Farabi, 61080 Trabzon (Turkey); Saricaoglu, Senem Tugra, E-mail: senem_tugra@hotmail.com [Karadeniz Technical University, Faculty of Dentistry, Department of Oral Diagnosis and Radiology, Farabi, 61080 Trabzon (Turkey); Can, Gamze, E-mail: gcanktu@yahoo.com [Karadeniz Technical University Faculty of Medicine Department of Public Health (Turkey)

    2011-11-15

    Aim: The aim of this study was to compare conventional radiography, storage phosphor plate, and cone beam computed tomography for in vitro determination of occlusal and approximal caries. Methods: A total of 72 extracted human premolar and molar teeth were selected. Teeth were radiographed with conventional intraoral radiography, a storage phosphor plate system, and cone beam computed tomography and evaluated by two observers. The teeth were then separated and examined with a stereomicroscope and a scanner at approximately 8x magnification. Results: CBCT was statistically superior to conventional radiography and phosphor plate for determining occlusal caries. No significant difference from CBCT, conventional radiography and the phosphor plate system for determining approximal caries was found. Conclusion: The CBCT system may be used as an auxiliary method for the detection of caries.

  7. An in vitro comparison of diagnostic abilities of conventional radiography, storage phosphor, and cone beam computed tomography to determine occlusal and approximal caries

    Aim: The aim of this study was to compare conventional radiography, storage phosphor plate, and cone beam computed tomography for in vitro determination of occlusal and approximal caries. Methods: A total of 72 extracted human premolar and molar teeth were selected. Teeth were radiographed with conventional intraoral radiography, a storage phosphor plate system, and cone beam computed tomography and evaluated by two observers. The teeth were then separated and examined with a stereomicroscope and a scanner at approximately 8x magnification. Results: CBCT was statistically superior to conventional radiography and phosphor plate for determining occlusal caries. No significant difference from CBCT, conventional radiography and the phosphor plate system for determining approximal caries was found. Conclusion: The CBCT system may be used as an auxiliary method for the detection of caries.

  8. Comparison of computed tomography with radiography as a noninvasive diagnostic technique for chronic nasal disease in dogs

    Computed tomography was evaluated as a noninvasive technique for the diagnosis of chronic nasal disease in dogs. Computed tomographic images, radiographs, and histopathologic findings were compared in 11 dogs with chronic nasal disease. Definitive diagnosis was made following traumatic nasal flush, exploratory surgery, or necropsy. The study included 8 dogs with intranasal tumors, 2 dogs with bacterial rhinitis (Pasteurella sp), and 1 dog with mycotic rhinitis (Aspergillus sp). Computed tomography was superior to radiography in defining the extent of the disease process and in differentiating infectious rhinitis from nasal neoplasms. It defined lesions in the palate, nasopharyngeal meatus, maxillary sinus, caudal ethmoturbinates, and periorbital tissues that were difficult to demonstrate by use of conventional radiography. Tumors appeared as space-occupying lesions that obliterated the turbinates, caused deviation of the nasal septum, and eroded bone. Rhinitis appeared as a cavitating lesion that spared the paranasal sinuses, thickened and distorted the turbinates, and widened the meatus. Although morphologically distinct on computed tomographic images, infectious rhinitis and nasal neoplasms could not be differentiated by attenuation measurements or degree of contrast enhancement. Computed tomography appeared to be a reliable, noninvasive technique for the diagnosis of chronic nasal disease in dogs, and a promising alternative to diagnostic techniques currently in use

  9. Computed image analysis of neutron radiographs

    Similar with X-radiography, using neutron like penetrating particle, there is in practice a nondestructive technique named neutron radiology. When the registration of information is done on a film with the help of a conversion foil (with high cross section for neutrons) that emits secondary radiation (β,γ) that creates a latent image, the technique is named neutron radiography. A radiographic industrial film that contains the image of the internal structure of an object, obtained by neutron radiography, must be subsequently analyzed to obtain qualitative and quantitative information about the structural integrity of that object. There is possible to do a computed analysis of a film using a facility with next main components: an illuminator for film, a CCD video camera and a computer (PC) with suitable software. The qualitative analysis intends to put in evidence possibly anomalies of the structure due to manufacturing processes or induced by working processes (for example, the irradiation activity in the case of the nuclear fuel). The quantitative determination is based on measurements of some image parameters: dimensions, optical densities. The illuminator has been built specially to perform this application but can be used for simple visual observation. The illuminated area is 9x40 cm. The frame of the system is a comparer of Abbe Carl Zeiss Jena type, which has been adapted to achieve this application. The video camera assures the capture of image that is stored and processed by computer. A special program SIMAG-NG has been developed at INR Pitesti that beside of the program SMTV II of the special acquisition module SM 5010 can analyze the images of a film. The major application of the system was the quantitative analysis of a film that contains the images of some nuclear fuel pins beside a dimensional standard. The system was used to measure the length of the pellets of the TRIGA nuclear fuel. (authors)

  10. Proton radiography and proton computed tomography based on time-resolved dose measurements.

    Testa, Mauro; Verburg, Joost M; Rose, Mark; Min, Chul Hee; Tang, Shikui; Bentefour, El Hassane; Paganetti, Harald; Lu, Hsiao-Ming

    2013-11-21

    We present a proof of principle study of proton radiography and proton computed tomography (pCT) based on time-resolved dose measurements. We used a prototype, two-dimensional, diode-array detector capable of fast dose rate measurements, to acquire proton radiographic images expressed directly in water equivalent path length (WEPL). The technique is based on the time dependence of the dose distribution delivered by a proton beam traversing a range modulator wheel in passive scattering proton therapy systems. The dose rate produced in the medium by such a system is periodic and has a unique pattern in time at each point along the beam path and thus encodes the WEPL. By measuring the time dose pattern at the point of interest, the WEPL to this point can be decoded. If one measures the time–dose patterns at points on a plane behind the patient for a beam with sufficient energy to penetrate the patient, the obtained 2D distribution of the WEPL forms an image. The technique requires only a 2D dosimeter array and it uses only the clinical beam for a fraction of second with negligible dose to patient. We first evaluated the accuracy of the technique in determining the WEPL for static phantoms aiming at beam range verification of the brain fields of medulloblastoma patients. Accurate beam ranges for these fields can significantly reduce the dose to the cranial skin of the patient and thus the risk of permanent alopecia. Second, we investigated the potential features of the technique for real-time imaging of a moving phantom. Real-time tumor tracking by proton radiography could provide more accurate validations of tumor motion models due to the more sensitive dependence of proton beam on tissue density compared to x-rays. Our radiographic technique is rapid (~100 ms) and simultaneous over the whole field, it can image mobile tumors without the problem of interplay effect inherently challenging for methods based on pencil beams. Third, we present the reconstructed p

  11. Proton radiography and proton computed tomography based on time-resolved dose measurements

    Testa, Mauro; Verburg, Joost M.; Rose, Mark; Min, Chul Hee; Tang, Shikui; Hassane Bentefour, El; Paganetti, Harald; Lu, Hsiao-Ming

    2013-11-01

    We present a proof of principle study of proton radiography and proton computed tomography (pCT) based on time-resolved dose measurements. We used a prototype, two-dimensional, diode-array detector capable of fast dose rate measurements, to acquire proton radiographic images expressed directly in water equivalent path length (WEPL). The technique is based on the time dependence of the dose distribution delivered by a proton beam traversing a range modulator wheel in passive scattering proton therapy systems. The dose rate produced in the medium by such a system is periodic and has a unique pattern in time at each point along the beam path and thus encodes the WEPL. By measuring the time dose pattern at the point of interest, the WEPL to this point can be decoded. If one measures the time-dose patterns at points on a plane behind the patient for a beam with sufficient energy to penetrate the patient, the obtained 2D distribution of the WEPL forms an image. The technique requires only a 2D dosimeter array and it uses only the clinical beam for a fraction of second with negligible dose to patient. We first evaluated the accuracy of the technique in determining the WEPL for static phantoms aiming at beam range verification of the brain fields of medulloblastoma patients. Accurate beam ranges for these fields can significantly reduce the dose to the cranial skin of the patient and thus the risk of permanent alopecia. Second, we investigated the potential features of the technique for real-time imaging of a moving phantom. Real-time tumor tracking by proton radiography could provide more accurate validations of tumor motion models due to the more sensitive dependence of proton beam on tissue density compared to x-rays. Our radiographic technique is rapid (˜100 ms) and simultaneous over the whole field, it can image mobile tumors without the problem of interplay effect inherently challenging for methods based on pencil beams. Third, we present the reconstructed p

  12. Chest radiography and thoracic computed tomography findings in children who have family members with active pulmonary tuberculosis

    Objective: The chest radiography and TCT findings in children who had contacted with adult family members with active pulmonary tuberculosis were compared. The contributions of thoracic computed tomography to the diagnosis of tuberculosis were investigated. Methods and material: The children who were 0-16 years old (n=173) and children of families with an adult member which was diagnosed as pulmonary tuberculosis were evaluated. The children were considered in two groups based on the absence (n=125) or presence (n=48) of complaints and/or ambiguous symptoms such as lack of appetite, mild cough, sweating, history of lung infection, low body weight and those with suspicious chest radiography findings (12 cases) were included in this study. Asymptomatic patients (n=125) did not undergo TCT. Patients who had positive PPD skin tests only received isoniazid. If the TCT demonstrated enlarged lymph nodes or parenchymal lesions, minimally active pulmonary tuberculosis was diagnosed and antituberculous treatment was given. Results and discussions: TCT revealed lymph node enlargement or parenchymal lesions in 39 children (81.2%). Of the 12 children whose CXRs revealed suspicious lymph node enlargement and/or infiltration, five had normal findings in TCT whereas the initial findings were confirmed in the remaining seven. These data suggest that there is a correlation between the presence of ambiguous symptoms in exposed children and TCT findings; chest radiography and TCT findings do not yield parallel findings. All the patients who received anti-TB treatment were resolved in the control examinations. Conclusion: In this study there is a correlation between presence of ambiguous symptoms and TCT findings, but the chest radiography and TCT findings do not yield harmony in exposed children with ambiguous symptoms (suspicious tuberculosis cases). These observations should be considered in children with symptoms similar to those of exposed children, but with no definite history of

  13. Quantitative kinetic analysis of lung nodules by temporal subtraction technique in dynamic chest radiography with a flat panel detector

    Tsuchiya, Yuichiro; Kodera, Yoshie; Tanaka, Rie; Sanada, Shigeru

    2007-03-01

    Early detection and treatment of lung cancer is one of the most effective means to reduce cancer mortality; chest X-ray radiography has been widely used as a screening examination or health checkup. The new examination method and the development of computer analysis system allow obtaining respiratory kinetics by the use of flat panel detector (FPD), which is the expanded method of chest X-ray radiography. Through such changes functional evaluation of respiratory kinetics in chest has become available. Its introduction into clinical practice is expected in the future. In this study, we developed the computer analysis algorithm for the purpose of detecting lung nodules and evaluating quantitative kinetics. Breathing chest radiograph obtained by modified FPD was converted into 4 static images drawing the feature, by sequential temporal subtraction processing, morphologic enhancement processing, kinetic visualization processing, and lung region detection processing, after the breath synchronization process utilizing the diaphragmatic analysis of the vector movement. The artificial neural network used to analyze the density patterns detected the true nodules by analyzing these static images, and drew their kinetic tracks. For the algorithm performance and the evaluation of clinical effectiveness with 7 normal patients and simulated nodules, both showed sufficient detecting capability and kinetic imaging function without statistically significant difference. Our technique can quantitatively evaluate the kinetic range of nodules, and is effective in detecting a nodule on a breathing chest radiograph. Moreover, the application of this technique is expected to extend computer-aided diagnosis systems and facilitate the development of an automatic planning system for radiation therapy.

  14. Neutron Radiography

    Reddy, A. R.; Rao, M. V. N.

    2012-01-01

    The field of neutron radiography with special reference to isotopic neutron radiography has been reviewed. Different components viz., sources, collimators, imaging systems are described. Various designs of neutron radiography facilities, their relative merits and demerits , the appropriateness of each design depending on the object to be radiographed, and economics of each technique are also dealt. The applications of neutron radiography are also briefly presented.

  15. Detection of radioactive fragments in patients after radiological or nuclear emergencies using computed tomography and digital radiography.

    Ören, Ü; Hansson, M; Mattsson, S; Rääf, C L

    2014-03-01

    A comparison has been carried out between standard-dose computed tomography, non-diagnostic computed tomography and digital radiography with respect to their suitability for detecting radioactive fragments associated with nuclear or radiological events such as debris from radiological dispersal devices. The purpose was to investigate if radiographic imaging is justified for the detection and localisation of radioactive fragments in affected patients. Fragments of uranium (U), copper (Cu), iron (Fe) and volcanic ash with effective diameters ranging from (approximately) 100 to 700 μm were selected. The fragments were positioned at two different locations on an anatomical torso phantom and images were produced with standard-dose CT, non-diagnostic CT and digital radiography. Capsules with radionuclides of (137)Cs, (60)Co and (99m)Tc were also positioned in the phantom and the effective doses were estimated for radionuclide exposures as well as for standard-dose CT, non-diagnostic CT and digital radiography. For standard-dose CT and digital radiography, U, Cu and Fe fragments were detected in sizes down to 100-180, 250-300 and 300-400 μm respectively. For the non-diagnostic CT the results were 180-250 μm (for U), 300-400 μm (for Cu) and 400-500 μm (for Fe). The effective dose from the standard-dose CT, non-diagnostic CT and digital radiography was 5.6, 1.9 and 0.76 mSv. Corresponding doses from (137)Co, (60)Co and (99m)Tc positioned at the site of fragments were in the range of 0.07-0.1, 0.32-0.45 and 0.08-0.09 mSv per MBq during 24 h. We conclude that, for a number of gamma emitters with activity levels on the order of magnitude of megabecquerel, imaging using ionising radiation can be justified since the effective dose from the radionuclides will exceed the dose from the radiological examination. PMID:24566375

  16. Computer aided diagnosis in digital chest radiography: evaluation of pulmonary emphysema in COPD patients

    Coppini, Giuseppe; Ferdeghini, Ezio Maria; Paterni, Marco; Tonelli, Lucia; Bauleo, Carolina; Monti, Simonetta; Miniati, Massimo

    2004-01-01

    Computer-aided quantitative analysis of chest radiographs is a useful tool in describing alterations in lung shape that occur in patients with emphysema. In the present study, the analysis was limited to the lateral chest radiograph, but we expect that the use of the postero-anterior view may further improve the rate of correct classification.

  17. Computational movement analysis

    Laube, Patrick

    2014-01-01

    This SpringerBrief discusses the characteristics of spatiotemporal movement data, including uncertainty and scale. It investigates three core aspects of Computational Movement Analysis: Conceptual modeling of movement and movement spaces, spatiotemporal analysis methods aiming at a better understanding of movement processes (with a focus on data mining for movement patterns), and using decentralized spatial computing methods in movement analysis. The author presents Computational Movement Analysis as an interdisciplinary umbrella for analyzing movement processes with methods from a range of fi

  18. Standard versus inverted digital luminescence radiography in detecting pulmonary nodules: A ROC analysis

    Kirchner, Johannes, E-mail: kirchner@akh-hagen.de [Department of Diagnostic and Interventional Radiology, Allgemeines Krankenhaus, Hagen (Germany); Gadek, Darius [Department of Diagnostic and Interventional Radiology, Allgemeines Krankenhaus, Hagen (Germany); Goltz, Jan-Peter [Department of Radiology, University Hospital of Wuerzburg, Wuerzburg (Germany); Doroch-Gadek, Anna; Stückradt, Sven [Department of Diagnostic and Interventional Radiology, Allgemeines Krankenhaus, Hagen (Germany); Liermann, Dieter [Department of Radiology, Katholisches Marienhospital Herne, Ruhr- University, Bochum (Germany); Kickuth, Ralph [Department of Radiology, University Hospital of Wuerzburg, Wuerzburg (Germany)

    2013-10-01

    Objective: Observer performance tests were conducted to compare the effect of presenting digital luminescence radiography (DLR) monitor images in positive mode (“bones black”) or negative mode (“bones white”) in the detectability of subtle lung nodules. Methods: Five radiologists independently reviewed digital radiographs of 55 patients with either (a) a single, small (6–12 mm), non- calcified peripheral nodule confirmed by chest CT (n = 47) or (b) normal finding (n = 8) confirmed by chest CT, respectively. Mean size of pulmonary nodules was 8.3 mm (range 6–12 mm, median 7 mm). Radiographs were displayed either in standard mode (bones white) or inverse intensity (bones black). A total of 550 observations resulted. For the evaluation ROC analysis was performed using a specialized computer algorithm. Results: The standard presentation mode showed a sensitivity of 61.7% and a specificity of 72.5%, the inverse presentation mode a sensitivity of 68.1% and a specificity of 75.0%. ROC- analysis showed that the difference between the standard mode (Az- value 0.694) and the inverse mode (Az- value 0.810) was significant in favour of the inverse presentation mode (p = 0.001). This finding was especially observed in more experienced radiologist (Az- values 0.716 vs. 0.909, P < 0.001). Conclusion: Our study demonstrates a significant advantage of the inverse mode in the detection of small pulmonary nodules compared with the commonly used negative mode when interpreted by more experienced radiologists. Advance in knowledge: Inverse intensity images (“bones black”) may have some advantages in the detection of small pulmonary nodules in experienced readers when presented on a stand-alone display.

  19. Free software for performing physical analysis of systems for digital radiography and mammography

    Donini, Bruno; Lanconelli, Nico, E-mail: nico.lanconelli@unibo.it [Alma Mater Studiorum, Department of Physics and Astronomy, University of Bologna, Bologna 40127 (Italy); Rivetti, Stefano [Fisica Medica, Ospedale di Sassuolo S.p.A., Sassuolo 41049 (Italy); Bertolini, Marco [Medical Physics Unit, Azienda Ospedaliera ASMN, Istituto di Ricovero e Cura a Carattere Scientifico, Reggio Emilia 42123 (Italy)

    2014-05-15

    Purpose: In this paper, the authors present a free software for assisting users in achieving the physical characterization of x-ray digital systems and image quality checks. Methods: The program was developed as a plugin of a well-known public-domain suite ImageJ. The software can assist users in calculating various physical parameters such as the response curve (also termed signal transfer property), modulation transfer function (MTF), noise power spectra (NPS), and detective quantum efficiency (DQE). It also includes the computation of some image quality checks: defective pixel analysis, uniformity, dark analysis, and lag. Results: The software was made available in 2009 and has been used during the last couple of years by many users who gave us valuable feedback for improving its usability. It was tested for achieving the physical characterization of several clinical systems for digital radiography and mammography. Various published papers made use of the outcomes of the plugin. Conclusions: This software is potentially beneficial to a variety of users: physicists working in hospitals, staff working in radiological departments, such as medical physicists, physicians, engineers. The plugin, together with a brief user manual, are freely available and can be found online ( http://www.medphys.it/downloads.htm ). With our plugin users can estimate all three most important parameters used for physical characterization (MTF, NPS, and also DQE). The plugin can run on any operating system equipped with ImageJ suite. The authors validated the software by comparing MTF and NPS curves on a common set of images with those obtained with other dedicated programs, achieving a very good agreement.

  20. Free software for performing physical analysis of systems for digital radiography and mammography

    Purpose: In this paper, the authors present a free software for assisting users in achieving the physical characterization of x-ray digital systems and image quality checks. Methods: The program was developed as a plugin of a well-known public-domain suite ImageJ. The software can assist users in calculating various physical parameters such as the response curve (also termed signal transfer property), modulation transfer function (MTF), noise power spectra (NPS), and detective quantum efficiency (DQE). It also includes the computation of some image quality checks: defective pixel analysis, uniformity, dark analysis, and lag. Results: The software was made available in 2009 and has been used during the last couple of years by many users who gave us valuable feedback for improving its usability. It was tested for achieving the physical characterization of several clinical systems for digital radiography and mammography. Various published papers made use of the outcomes of the plugin. Conclusions: This software is potentially beneficial to a variety of users: physicists working in hospitals, staff working in radiological departments, such as medical physicists, physicians, engineers. The plugin, together with a brief user manual, are freely available and can be found online ( http://www.medphys.it/downloads.htm ). With our plugin users can estimate all three most important parameters used for physical characterization (MTF, NPS, and also DQE). The plugin can run on any operating system equipped with ImageJ suite. The authors validated the software by comparing MTF and NPS curves on a common set of images with those obtained with other dedicated programs, achieving a very good agreement

  1. Non-destructive analysis of rape plant pod by neutron radiography

    Since the ripening process of the rape plant pod has not been studied well, non-destructive analysis of the pod has been carried out by neutron radiography. From the water distribution in the pod, the formation of pod parenchyma as well as vascular system were clearly observed. During the ripening process of the pod water content and weight of the seed were measured. It was found that at the early stage of the ripening process the water content of the seed became maximum and began to decrease, whereas the weight of each seed was gradually increased throughout the ripening process. Neutron radiography, which shows the water content of the pod, will give the clue to the decrease of the water content of the seed from the middle of the ripening process. (author)

  2. Comparative reject analysis in conventional film-screen and digital storage phosphor radiography

    The aim of this study was comparative analysis of rejected radiographs in conventional and digital radiology under the aspects number of rejected images and reasons for rejection. During 2 months waste films of conventional radiography were collected; in digital radiography each image-delete command at the postprocessing workstation was documented. Rejected images were analysed and assigned to four categories. The overall reject rate was 27.6 % in the conventional and 2.3 % in the digital department. Whereas in the conventional department the main reason for rejection was ''exposure'' and ''others'' (i. e. problems related to film handling), the main reason in the digital environment was ''positioning''. The high exposure tolerance of digital systems markedly reduces the amount of faulty images. This is not only economically rewarding, but may also reduce unnecessary X-ray exposure of patients due to image retake. (orig.)

  3. Assessment of survey radiography and comparison with x-ray computed tomography for detection of hyperfunctioning adrenocortical tumors in dogs

    Results of abdominal survey radiography and x-ray computed tomography (CT) were compared in 13 dogs with hyperadrenocorticism histologically attributed to adrenocortical tumors. X-ray computed tomography enabled accurate localization of the tumor in all 13 dogs. Apart from 2 poorly demarcated irregular-shaped and mineralized carcinomas, there were no differences between adenoma (n = 3) and carcinoma (n = 10) on CT images. In 1 dog, invasion of the caudal vena cava by the tumor was suggested on CT images and was confirmed during surgery. Suspicion of adhesions between tumors of the right adrenal gland and the caudal vena cava on the basis of CT images was confirmed during surgery in only 2 of 6 dogs. Survey radiography allowed accurate localization of the tumor in 7 dogs (4 on the right side and 3 on the left). In 6 of these dogs, the tumor was visible as a well-demarcated soft tissue mass and, in the other dog, as a poorly demarcated mineralized mass. The smallest tumor visualized on survey radiographs had a diameter of 20 mm on CT images. Six tumors with diameter less than or equal to 20 mm were not visualized on survey radiographs. In 1 of these dogs, a mineralized nodule was found in the left adrenal region, without evidence of a mass. In a considerable number of cases, survey radiography can provide presurgical localization of adrenocortical tumors in dogs with hyperadrenocorticism; CT is redundant in these instances. In the absence of positive radiographic findings, CT is valuable for localization of adrenocortical tumors

  4. Neutron radiography and X-ray computed tomography for quantifying weathering and water uptake processes inside porous limestone used as building material

    Euville and Savonnières limestones were weathered by acid test and this resulted in the formation of a gypsum crust. In order to characterize the crystallization pattern and the evolution of the pore structure below the crust, a combination of high resolution X-ray computed tomography and SEM–EDS was used. A time lapse sequence of the changing pore structure in both stones was obtained and afterwards quantified by using image analysis. The difference in weathering of both stones by the same process could be explained by the underlying microstructure and texture. Because water and moisture play a crucial role in the weathering processes, water uptake in weathered and non-weathered samples was characterized based on neutron radiography. In this way the water uptake was both visualized and quantified in function of the height of the sample and in function of time. In general, the formation of a gypsum crust on limestone slows down the initial water uptake in the materials. - Highlights: • Time lapse sequence in 3D of changing pore structures inside limestone • A combination of X-ray CT, SEM and neutron radiography was used. • Quantification of water content in function of time, height and weathering • Characterization of weathering processes due to gypsum crystallization

  5. Three-dimensional biplanar radiography as a new means of accessing femoral version: a comparitive study of EOS three-dimensional radiography versus computed tomography

    Pomerantz, M.L. [University of California San Diego School of Medicine, Orthopaedic Surgery Department, San Diego, CA (United States); Glaser, Diana [Aurora Spine, Carlsbad, CA (United States); Doan, Josh [Orthopedic Biomechanics Research Center, San Diego, CA (United States); Kumar, Sita [University of California, San Diego, CA (United States); Edmonds, Eric W. [University of California San Diego School of Medicine, Orthopaedic Surgery Department, San Diego, CA (United States); Rady Children' s Hospital San Diego, Division of Orthopedic Surgery, San Diego, CA (United States)

    2014-10-17

    To validate femoral version measurements made from biplanar radiography (BR), three-dimensional (3D) reconstructions (EOS imaging, France) were made in differing rotational positions against the gold standard of computed tomography (CT). Two cadaveric femurs were scanned with CT and BR in five different femoral versions creating ten total phantoms. The native version was modified by rotating through a mid-diaphyseal hinge twice into increasing anteversion and twice into increased retroversion. For each biplanar scan, the phantom itself was rotated -10, -5, 0, +5 and +10 . Three-dimensional CT reconstructions were designated the true value for femoral version. Two independent observers measured the femoral version on CT axial slices and BR 3D reconstructions twice. The mean error (upper bound of the 95 % confidence interval), inter- and intraobserver reliability, and the error compared to the true version were determined for both imaging techniques. Interobserver intraclass correlation for CT axial images ranged from 0.981 to 0.991, and the intraobserver intraclass correlation ranged from 0.994 to 0.996. For the BR 3D reconstructions these values ranged from 0.983 to 0.998 and 0.982 to 0.998, respectively. For the CT measurements the upper bound of error from the true value was 5.4-7.5 , whereas for BR 3D reconstructions it was 4.0-10.1 . There was no statistical difference in the mean error from the true values for any of the measurements done with axial CT or BR 3D reconstructions. BR 3D reconstructions accurately and reliably provide clinical data on femoral version compared to CT even with rotation of the patient of up to 10 from neutral. (orig.)

  6. Three-dimensional biplanar radiography as a new means of accessing femoral version: a comparitive study of EOS three-dimensional radiography versus computed tomography

    To validate femoral version measurements made from biplanar radiography (BR), three-dimensional (3D) reconstructions (EOS imaging, France) were made in differing rotational positions against the gold standard of computed tomography (CT). Two cadaveric femurs were scanned with CT and BR in five different femoral versions creating ten total phantoms. The native version was modified by rotating through a mid-diaphyseal hinge twice into increasing anteversion and twice into increased retroversion. For each biplanar scan, the phantom itself was rotated -10, -5, 0, +5 and +10 . Three-dimensional CT reconstructions were designated the true value for femoral version. Two independent observers measured the femoral version on CT axial slices and BR 3D reconstructions twice. The mean error (upper bound of the 95 % confidence interval), inter- and intraobserver reliability, and the error compared to the true version were determined for both imaging techniques. Interobserver intraclass correlation for CT axial images ranged from 0.981 to 0.991, and the intraobserver intraclass correlation ranged from 0.994 to 0.996. For the BR 3D reconstructions these values ranged from 0.983 to 0.998 and 0.982 to 0.998, respectively. For the CT measurements the upper bound of error from the true value was 5.4-7.5 , whereas for BR 3D reconstructions it was 4.0-10.1 . There was no statistical difference in the mean error from the true values for any of the measurements done with axial CT or BR 3D reconstructions. BR 3D reconstructions accurately and reliably provide clinical data on femoral version compared to CT even with rotation of the patient of up to 10 from neutral. (orig.)

  7. Gamma radiography and its technological application

    After the presentation of gamma radiography and X-ray radiography, the author compare both techniques showing, in particular, the greater utility of gamma radiography in industrial diagnostic and more particularly on works site diagnostic. Problem of using radiography and safety consideration will be studied. Figures shows two radiography equipment which have been designed for gamma radiography respecting the safety regulations required by the Radioisotope Inter-ministerial Commission. In the second part, different techniques and uses of gamma radiography are briefly described : xerography, neutron radiography, fluoroscopy and imaging amplifier, tomography, betatrons and linear accelerators. Cost analysis will discussed in conclusion. (M.P.)

  8. Parameter analysis of radiography film for TC use

    The possibilities of use x-ray industrial films on the projection survey for image processing, jointly with the noise analysis in films, when used as a radiation detectors in computerized tomography are studied. (C.G.C.)

  9. Central axis dose verification in patients treated with total body irradiation of photons using a Computed Radiography system

    To propose and evaluate a method for the central axis dose verification in patients treated with total body irradiation (TBI) of photons using images obtained through a Computed Radiography (CR) system. It was used the Computed Radiography (Fuji) portal imaging cassette readings and correlate with measured of absorbed dose in water using 10 x 10 irradiation fields with ionization chamber in the 60Co equipment. The analytical and graphic expression is obtained through software 'Origin8', the TBI patient portal verification images were processed using software ImageJ, to obtain the patient dose. To validate the results, the absorbed dose in RW3 models was measured with ionization chamber with different thickness, simulating TBI real conditions. Finally it was performed a retrospective study over the last 4 years obtaining the patients absorbed dose based on the reading in the image and comparing with the planned dose. The analytical equation obtained permits estimate the absorbed dose using image pixel value and the dose measured with ionization chamber and correlated with patient clinical records. Those results are compared with reported evidence obtaining a difference less than 02%, the 3 methods were compared and the results are within 10%. (Author)

  10. Computer Programming Job Analysis

    Debdulal Dutta Roy

    2002-01-01

    This study investigated relative uses of computer programming job characteristics across different organizations and effects of different demographic variables on job analysis ratings. Data were collected from 201 computer programers of 6 different organizations through checklist. Principal component analysis noted four mostly used job characteristics as program writing and testing, human relations, data analysis and user satisfaction. Of them only data analysis differed among different organ...

  11. Radiography - A conceptual approach

    Aim: The purpose of this article is to describe interdisciplinary comparison of the attributes of the concept of radiography in health sciences, physics and technology on the grounds of concept analysis. Background: The concept of radiography is widely used in health sciences, physics and technology. However, the content of the concept may vary. In order to clarify the concept of radiography, the concept must be systematically examined and defined in linguistic form. Method: The concept of radiography was analysed by using the evolutionary method of concept analysis. The data were collected through discretionary sampling and consisted of literature and Internet pages. Qualitative content analysis was employed for analysing the data. Findings: As a result of concept analysis, the concept of radiography in health sciences was determined as expertise of radiographers in the use of radiation, which is dual, dynamic, social and situation-related in nature, and typically based on versatile synthesis. Regarding the attributes identified, the concept of radiography has both similarities and differences between health sciences, physics and technology. Conclusions: The concept of radiography was found to be more abstract, wider, more complex and more radiographer-centred in health sciences than in other disciplines. The content of the concept of radiography seems to vary according to the discipline

  12. Detection of moisture behavior in building materials in isothermal state by neutron radiography and numerical analysis

    This research focused on the water absorption behavior in water retentive materials and water permeable materials, by using the neutron radiography technique. The moisture characteristic curve, which is hydraulic diffusivity as a function of volumetric moisture content, was calculated with pore size distribution of the both materials, and an unsteady water diffusion analysis was conducted. The experimentally observed water behaviors by the absorption test were well captured by the diffusion analysis. And also the results showed that the gravity effect for calculation of water movement in the water retentive and permeable materials was considerable in comparably rapid water movement. (author)

  13. Skeletal imaging following reconstruction of the posterior cruciate ligament: in vivo comparison of fluoroscopy, radiography, and computed tomography

    Osti, Michael; Benedetto, Karl Peter [Academic Hospital Feldkirch, Department for Trauma Surgery and Sports Traumatology, Feldkirch (Austria); Krawinkel, Alessa [Academic Hospital Feldkirch, Department for Radiology, Feldkirch (Austria)

    2014-12-15

    Intra- and postoperative validation of anatomic footprint replication in posterior cruciate ligament (PCL) reconstruction can be conducted using fluoroscopy, radiography, or computed tomography (CT) scans. However, effectiveness and exposure to radiation of these imaging modalities are unknown. The objective of this study was to evaluate the comparative effectiveness of fluoroscopy, radiography, and CT in detecting femoral and tibial tunnel positions following an all-inside reconstruction of the PCL ligament in vivo. The study design was a retrospective case series. Intraoperative fluoroscopic images, postoperative radiographs, and CT scans were obtained in 50 consecutive patients following single-bundle PCL reconstruction. The centers of the tibial and femoral tunnel apertures were identified and correlated to measurement grid systems. The results of fluoroscopic, radiographic, and CT measurements were compared to each other and accumulated radiation dosages were calculated. Comparing the imaging groups, no statistically significant difference could be detected for the reference of the femoral tunnel to the intercondylar depth and height, for the reference of the tibial tunnel to the mediolateral diameter of the tibial plateau and for the superoinferior distance of the tibial tunnel entry to the tibial plateau and to the former physis line. Effective doses resulting from fluoroscopic, radiographic, and CT exposure averaged 2.9 mSv, standard deviation (±SD) 4.1 mSv, to 1.3 ± 0.8 mSv and to 3.6 ± 1.0 mSv, respectively. Fluoroscopy, radiography, and CT yield approximately equal effectiveness in detecting parameters used for quality validation intra- and postoperatively. An accumulating exposure to radiation must be considered. (orig.)

  14. Skeletal imaging following reconstruction of the posterior cruciate ligament: in vivo comparison of fluoroscopy, radiography, and computed tomography

    Intra- and postoperative validation of anatomic footprint replication in posterior cruciate ligament (PCL) reconstruction can be conducted using fluoroscopy, radiography, or computed tomography (CT) scans. However, effectiveness and exposure to radiation of these imaging modalities are unknown. The objective of this study was to evaluate the comparative effectiveness of fluoroscopy, radiography, and CT in detecting femoral and tibial tunnel positions following an all-inside reconstruction of the PCL ligament in vivo. The study design was a retrospective case series. Intraoperative fluoroscopic images, postoperative radiographs, and CT scans were obtained in 50 consecutive patients following single-bundle PCL reconstruction. The centers of the tibial and femoral tunnel apertures were identified and correlated to measurement grid systems. The results of fluoroscopic, radiographic, and CT measurements were compared to each other and accumulated radiation dosages were calculated. Comparing the imaging groups, no statistically significant difference could be detected for the reference of the femoral tunnel to the intercondylar depth and height, for the reference of the tibial tunnel to the mediolateral diameter of the tibial plateau and for the superoinferior distance of the tibial tunnel entry to the tibial plateau and to the former physis line. Effective doses resulting from fluoroscopic, radiographic, and CT exposure averaged 2.9 mSv, standard deviation (±SD) 4.1 mSv, to 1.3 ± 0.8 mSv and to 3.6 ± 1.0 mSv, respectively. Fluoroscopy, radiography, and CT yield approximately equal effectiveness in detecting parameters used for quality validation intra- and postoperatively. An accumulating exposure to radiation must be considered. (orig.)

  15. PyRAT (python radiography analysis tool): overview

    Armstrong, Jerawan C [Los Alamos National Laboratory; Temple, Brian A [Los Alamos National Laboratory; Buescher, Kevin L [Los Alamos National Laboratory

    2011-01-14

    PyRAT was developed as a quantitative tool for robustly characterizing objects from radiographs to solve problems such as the hybrid nonlinear inverse problem. The optimization software library that was used is the nonsmooth optimization by MADS algorithm (NOMAD). Some of PyRAT's features are: (1) hybrid nonlinear inverse problem with calculated x-ray spectrum and detector response; (2) optimization based inversion approach with goal of identifying unknown object configurations - MVO problem; (3) using functionalities of Python libraries for radiographic image processing and analysis; (4) using the Tikhonov regularization method of linear inverse problem to recover partial information of object configurations; (5) using a priori knowledge of problem solutions to define feasible region and discrete neighbor for the MVO problem - initial data analysis + material library {yields} a priori knowledge; and (6) using the NOMAD (C++ version) software in the object.

  16. Neutron Radiography

    A. R. Reddy

    1982-07-01

    Full Text Available The field of neutron radiography with special reference to isotopic neutron radiography has been reviewed. Different components viz., sources, collimators, imaging systems are described. Various designs of neutron radiography facilities, their relative merits and demerits , the appropriateness of each design depending on the object to be radiographed, and economics of each technique are also dealt. The applications of neutron radiography are also briefly presented.

  17. Correct averaging in transmission radiography: Analysis of the inverse problem

    Wagner, Michael; Hampel, Uwe; Bieberle, Martina

    2016-05-01

    Transmission radiometry is frequently used in industrial measurement processes as a means to assess the thickness or composition of a material. A common problem encountered in such applications is the so-called dynamic bias error, which results from averaging beam intensities over time while the material distribution changes. We recently reported on a method to overcome the associated measurement error by solving an inverse problem, which in principle restores the exact average attenuation by considering the Poisson statistics of the underlying particle or photon emission process. In this paper we present a detailed analysis of the inverse problem and its optimal regularized numerical solution. As a result we derive an optimal parameter configuration for the inverse problem.

  18. The analysis of the imaging speed of the neutron digital radiography system based CCD

    The imaging speed is the main character of the neutron digital radiography system, and the calculating method of neutron digital radiography based CCD is put forward according to the characters of CCD and the principal of neutron digital radiography and optics. Then the imaging speed of neutron radiography system in SPRR-300 is calculated by the method. The experiment shows the counted value basically tallies with the measured value, then the calculating method is believable. (authors)

  19. Accuracy of Digital Radiography and Cone Beam Computed Tomography on Periapical Radiolucency Detection in Endodontically Treated Teeth

    Tadas Venskutonis

    2014-07-01

    Full Text Available Objectives: The aim of the present study was to compare the accuracy of intraoral digital periapical radiography and cone beam computed tomography in the detection of periapical radiolucencies in endodontically treated teeth. Material and Methods: Radiographic images (cone beam computed tomography [CBCT] scans and digital periapical radiography [PR] images from 60 patients, achieved from September 2008 to July 2013, were retrieved from databases of the Department of Oral Diseases, Lithuanian University of Health Sciences. Twenty patients met inclusion criteria and were selected for further evaluation. Results: In 20 patients (42.4 [SD 12.1] years, 65% men and 35% women a total of 35 endodontically treated teeth (1.75 [SD 0.91]; 27 in maxilla and 8 in mandible were evaluated. Overall, it was observed a statistical significant difference between the number of periapical lesions observed in the CBCT (n = 42 and radiographic (n = 24 examinations (P < 0.05. In molar teeth, CBCT identify a significantly higher amount of periapical lesions than with the radiographic method (P < 0.05. There were significant differences between CBCT and PR in the mean number of lesions identified per tooth (1.2 vs 0.66, P = 0.03, number of teeth with lesions (0.71 vs 0.46, P = 0.03 and number of lesions identified per canal (0.57 vs 0.33, P = 0.005. Considering CBCT as “gold standard” in lesion detection with the sensitivity, specificity and accuracy considering as score 1, then the same parameters of PR were 0.57, 1 and 0.76 respectively. Conclusions: Within the limitations of the present study, it can be concluded that cone beam computed tomography scans were more accurate compared to digital periapical radiographs for detecting periapical radiolucencies in endodontically treated teeth. The difference was more pronounced in molar teeth.

  20. National data analysis of general radiography projection method in medical imaging

    Kim, Jung Su; Seo, Deok Nam; Choi, In Seok [Dept. of Bio-Convergence Engineering, Korea University Graduate School, Seoul (Korea, Republic of); and others

    2014-09-15

    According to database of medical institutions of health insurance review and assessment service in 2013, 1,118 hospitals and clinics have department of radiology in Korea. And there are CT, fluoroscopic and general radiographic equipment in those hospitals. Above all, general radiographic equipment is the most commonly used in the radiology department. And most of the general radiographic equipment are changing the digital radiography system from the film-screen types of the radiography system nowadays. However, most of the digital radiography department are used the film-screen types of the radiography system. Therefore, in this study, we confirmed present conditions of technical items for general radiography used in hospital and research on general radiographic techniques in domestic medical institutions. We analyzed 26 radiography projection method including chest, skull, spine and pelvis which are generally used in the radiography department.

  1. National data analysis of general radiography projection method in medical imaging

    According to database of medical institutions of health insurance review and assessment service in 2013, 1,118 hospitals and clinics have department of radiology in Korea. And there are CT, fluoroscopic and general radiographic equipment in those hospitals. Above all, general radiographic equipment is the most commonly used in the radiology department. And most of the general radiographic equipment are changing the digital radiography system from the film-screen types of the radiography system nowadays. However, most of the digital radiography department are used the film-screen types of the radiography system. Therefore, in this study, we confirmed present conditions of technical items for general radiography used in hospital and research on general radiographic techniques in domestic medical institutions. We analyzed 26 radiography projection method including chest, skull, spine and pelvis which are generally used in the radiography department

  2. Position of the impacted third molar in relation to the mandibular canal. Diagnostic accuracy of cone beam computed tomography compared with panoramic radiography.

    Ghaeminia, H.; Meijer, G.J.; Soehardi, A.; Borstlap, W.A.; Mulder, J.; Berge, S.J.

    2009-01-01

    This study investigated the diagnostic accuracy of cone beam computed tomography (CBCT) compared to panoramic radiography in determining the anatomical position of the impacted third molar in relation with the mandibular canal. The study sample comprised 53 third molars from 40 patients with an incr

  3. Influence of imaging factors on image quality in bovine computed radiography (CR) using portable X-ray equipment

    The purpose of this study was to investigate the effect of X-ray tube-cassette distance and image scanning time on image quality to establish the benefit of Computed Radiography (CR) in bovine clinical practice. The tube-cassette distance had no effect on the visual evaluation score (graininess and sharpness). The image scanning time correlated with graininess but not sharpness. From these results, it was concluded that accidental variations in the tube-cassette distance and variations in image scanning time of several hours will not be major problems in clinical practice. CR is considered a useful X-ray system in bovine clinical imaging in which the maintenance of reproducible tube-cassette distance is difficult and variations in image scanning time is assumed

  4. Performance evaluation of three computed radiography systems using methods recommended in American Association of Physicists in Medicine Report 93

    The performances of three clinical computed radiography (CR) systems (Agfa CR 75 (with CRMD 4. 0 image plates), Kodak CR 850 (with Kodak GP plates) and Kodak CR 850A (with Kodak GP plates) were evaluated using six tests recommended in American Association of Physicists in Medicine Report 93. The results indicated variable performances with majority being within acceptable limits. The variations were mainly attributed to differences in detector formulations, plate readers' characteristics, and aging effects. The differences of the mean low contrast scores between the imaging systems for three observers were statistically significant for Agfa and Kodak CR 850A (P=0.009) and for Kodak CR systems (P=0.006) probably because of the differences in ages. However, the differences were not statistically significant between Agfa and Kodak CR 850 (P=0.284) suggesting similar perceived image quality. The study demonstrates the need to implement quality control program regularly. (author)

  5. Evaluation of an edge method for computed radiography and an electronic portal imaging device in radiotherapy: Image quality measurements

    Son, Soon-Yong; Choe, Bo-Young; Lee, Jeong-Woo; Kim, Jung-Min; Jeong, Hoi-Woun; Kim, Ham-Gyum; Kim, Wha-Sun; Lyu, Kwang-Yeul; Min, Jung-Whan; Kim, Ki-Won

    2014-12-01

    Regular quality assurance (QA) of image quality is essential for reasonable patient dose and accurate treatment. Thus, QA should be performed as a routine for correction. The purpose of this study was to evaluate the modulation transfer function (MTF), the noise power spectrum (NPS) and the detective quantum efficiency (DQE) of the computed radiography (CR) system and the digital radiography (DR) system by using the edge method in megavoltage X-ray imaging (MVI). We used an edge block, which consisting of tungsten with dimensions of 19 (thickness) × 10 (length) × 1 (width) cm3 and measured the pre-sampling MTF by using a 6-megavolt (MV) energy. Computed radiography with an image plate (CR-IP) showed the values of 0.4 mm-1 and 1.19 mm-1 for MTF 0.5 and 0.1. In the DR group, Elekta iViewGT showed the highest value of 0.27 mm-1 for MTF 0.5, and Siemens BEAMVIEW PLUS showed the highest value of 0.98 mm-1 for MTF 0.1. In CR, the NPS of CR-IP showed a favorable noise distribution. Thus, in the DR group, the NPS of Elekta iViewGT showed the highest noise distribution. CR-IP showed values at peak DQE and 1 mm-1 DQE of 0.0013 and 0.00011, respectively. In the DR group, Elekta iViewGT showed the best efficiency at a peak DQE of 0.0009, and Siemens BEAMVIEW PLUS showed the best efficiency at a 1-mm-1 DQE of 0.000008. The edge method produced fast assessments of the MTF and the DQE. We could validate the evaluation of the edge method by comparing of the CR system to the DR system. This study demonstrated that the edge method can be used for not only traditional QA imaging but also quantitative MTF, NPS and DQE measurements in detector development.

  6. Control dose in chest radiography after the installation of the computed radiography; Control de dosis impartidas en radiografia de torax tras la instalacion de un sistema de radiografia computerizada

    Minano Herrero, J. A.; Solar Cantos, M. M.; Roldan Arjona, J. M.; Martinez Cobos, R.

    2006-07-01

    The aim of this work is to verify patient does after the installation of the computed radiography. Entrance surface doses were obtained from a measurement of the output of the x-ray tube and exposure factor used at posteroanterior (PA) and lateral (LAT) chest in 50 adult patients before and after the installation. The obtained average values were 0.28{+-}0.10mGy in the PA view and 0.8{+-}0.5 mGy in the LAT view with the conventional screen-film system 0.27{+-}0.06 mGy in PA view and 0.69{+-}0.18 mGy in LAT view with the digital radiography system. The results do not exceed the diagnostic reference levels (DRLs) and are constant after the change of system. (Author)

  7. neutron radiography

    Neutron radiography (or radiology) is a diverse filed that uses neutrons of various energies, subthermal, thermal, epithermal or fast in either steady state or pulsed mode to examine objects for industrial, medical, or other purposes, both microscopic and macroscopic. The applications include engineering design, biological studies, nondestructive inspection and materials evaluation. In the past decade, over 100 different centers in some 30 countries have published reports of pioneering activities using reactors, accelerators and isotopic neutron sources. While film transparency and electronic video are most common imaging methods for static or in motion objects respectively, there are other important data gathering techniques, including track etch, digital gauging and computed tomography. A survey of the world-wide progress shows the field to be gaining steadily in its diversity, its sophistication and its importance. (author)

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

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

  9. Basic studies of radiation image diagnosis in veterinary medicine, 1: Comparison of the resolution of computed tomography, scanography and conventional radiography in an equine thoracic phantom

    In radiography of the thorax and abdomen of a large animal, the extreme thickness of the body causes a large amount of scattered radiation, which makes it difficult to obtain sharp images. The image resolutions of radiographs obtained by applying conventional radiography, scanography and computed tomography [CT] on an equine thoracic phantom were compared. Tubes of various inside diameters, used to simulate the pulmonary vessels were placed in an equine thoracic phantom and radiographed by CT, scanography and conventional radiography so as to compare the various degrees of resolution of the images of the tubes obtained by these methods. CT and scanography both gave a higher resolution index than conventional radiography, and both provided recognizable images of tubes < 2 mm in diameter, which conventional radiography failed to do. Scanography and CT can be used to obtain high-quality images of the thorax and abdomen of large animals. The image quality was compared using the resolution index (RI). The RI would be a wholly practical and comprehensive index for resolution because it includes 3 factors, contrast, sharpness and magnification, and yet is easy to calculate

  10. Computational Music Analysis

    This book provides an in-depth introduction and overview of current research in computational music analysis. Its seventeen chapters, written by leading researchers, collectively represent the diversity as well as the technical and philosophical sophistication of the work being done today in this...... well-established theories in music theory and analysis, such as Forte's pitch-class set theory, Schenkerian analysis, the methods of semiotic analysis developed by Ruwet and Nattiez, and Lerdahl and Jackendoff's Generative Theory of Tonal Music. The book is divided into six parts, covering...... music analysis, the book provides an invaluable resource for researchers, teachers and students in music theory and analysis, computer science, music information retrieval and related disciplines. It also provides a state-of-the-art reference for practitioners in the music technology industry....

  11. Comparative of radiation dose and image quality of Conventional Multislice Computed Tomography (MSCT, Cone-Beam CT (CBCT and periapical radiography in dental imaging

    Nasrollah Jabbari

    2016-03-01

    Full Text Available Background and Aims: With the increasing use of CT (Computed Tomoghraphy scans in dentistry especially in the implantology, there may be significant increases in the radiation exposure and its risk. During the last year’s ConeBeam Computed Tomoghraphy (CBCT has been introduced as an imaging modality for dentistry. The aim of this review article was to present comprehensive information have been published, regarding the  radiation dose and image quality of Conventional Multislice Computed Tomography (MSCT, Cone-Beam CT (CBCT and periapical radiography in dentistry imaging. Materials and Methods: A review of the literature was carried out in PubMed, Google Scholar, Science Direct and Scopus database using key words (CBCT, MSCT, periapical radiography, radiation dose of dentistry and image quality. These searches were limited to the articles published between the years of 1993 to 2015. Conclusion: In comparison to MSCT, CBCT had a short scanning times and lower radiation dose, but in comparison to periapical radiography, CBCT had higher radiation dose. In contrast, CBCT with flat panel detector had higher spatial resolution to MSCT. The periapical radiography also had a good image contrast and relatively high resolution. Generally, CBCT was suitable for hard tissue imaging and MSCT was preferred for soft tissue imaging.

  12. A comparative study of cone-beam computed tomography and digital periapical radiography in detecting mandibular molars root perforations

    Haghanifar, Sina; Moudi, Ehsan; Mesgarani, Abbas; Abbaszadeh, Naghi [Dental Material Research Center, Dental Faculty, Babol University of Medical Sciences, Babol (Iran, Islamic Republic of); Bijani, Ali [Non-Communicable Pediatric Diseases Research Center, Babol University of Medical Sciences, Babol (Iran, Islamic Republic of)

    2014-06-15

    The aim of this in vitro study was to determine the sensitivity and specificity of cone-beam computed tomography (CBCT) and digital periapical radiography in the detection of mesial root perforations of mandibular molars. In this in vitro study, 48 mandibular molars were divided into 4 groups. First, the mesial canals of all the 48 teeth were endodontically prepared. In 2 groups (24 teeth each), the roots were axially perforated in the mesiolingual canal 1-3 mm below the furcation region, penetrating the root surface ({sup r}oot perforation{sup )}. Then, in one of these 2 groups, the mesial canals were filled with gutta-percha and AH26 sealer. Mesial canals in one of the other 2 groups without perforation (control groups) were filled with the same materials. The CBCT and periapical radiographs with 3 different angulations were evaluated by 2 oral and maxillofacial radiologists. The specificity and sensitivity of the two methods were calculated, and P<0.05 was considered significant. The sensitivity and specificity of CBCT scans in the detection of obturated root canal perforations were 79% and 96%, respectively, and in the case of three-angled periapical radiographs, they were 92% and 100%, respectively. In non-obturated root canals, the sensitivity and specificity of CBCT scans in perforation detection were 92% and 100%, respectively, and for three-angled periapical radiographs, they were 50% and 96%, respectively. For perforation detection in filled-root canals, periapical radiography with three different horizontal angulations would be trustworthy, but it is recommended that CBCT be used for perforation detection before obturating root canals.

  13. A comparative study of cone-beam computed tomography and digital periapical radiography in detecting mandibular molars root perforations

    The aim of this in vitro study was to determine the sensitivity and specificity of cone-beam computed tomography (CBCT) and digital periapical radiography in the detection of mesial root perforations of mandibular molars. In this in vitro study, 48 mandibular molars were divided into 4 groups. First, the mesial canals of all the 48 teeth were endodontically prepared. In 2 groups (24 teeth each), the roots were axially perforated in the mesiolingual canal 1-3 mm below the furcation region, penetrating the root surface (root perforation). Then, in one of these 2 groups, the mesial canals were filled with gutta-percha and AH26 sealer. Mesial canals in one of the other 2 groups without perforation (control groups) were filled with the same materials. The CBCT and periapical radiographs with 3 different angulations were evaluated by 2 oral and maxillofacial radiologists. The specificity and sensitivity of the two methods were calculated, and P<0.05 was considered significant. The sensitivity and specificity of CBCT scans in the detection of obturated root canal perforations were 79% and 96%, respectively, and in the case of three-angled periapical radiographs, they were 92% and 100%, respectively. In non-obturated root canals, the sensitivity and specificity of CBCT scans in perforation detection were 92% and 100%, respectively, and for three-angled periapical radiographs, they were 50% and 96%, respectively. For perforation detection in filled-root canals, periapical radiography with three different horizontal angulations would be trustworthy, but it is recommended that CBCT be used for perforation detection before obturating root canals.

  14. Computed radiography plus rhythm software platform for FAC inspection in nuclear secondary circuit

    Koetz, A.; Delannoy, L. [GE Sensing and Inspection Technologies, Skaneateles (United States); Knook, T. [EDF DTG, Grenoble (France)

    2011-07-01

    This paper will cover determining and ensuring proper follow up of Flow Accelerated Corrosion (FAC) in secondary circuit of Nuclear Power Plant using digital radiography. What are the relevant parameters on the pipes and weld wall thickness reading. How precise and reliable are the data and how best to record and archive. One challenge always faced with inspections is how to share the data and gain expert opinion when the expert is on-site; with digital inspection data and the use of software tools this challenge can be overcome. As you begin to collect all the inspection data the true 'power of the data' can be unfolded. Archiving of digital inspection data provides the foundation of asset management, allowing you to look at trends over time throughout inspection results done in one plant or multiple locations around the world. This document describes the process and results of tests performed through digital radiographic technic for the detection and sizing of thickness losses in weld roots areas. The tests were performed according to a pre-established program including a phase of testing on standard blocks and tubes and a phase of testing on components with real defects. (authors)

  15. Computer aided safety analysis

    The document reproduces 20 selected papers from the 38 papers presented at the Technical Committee/Workshop on Computer Aided Safety Analysis organized by the IAEA in co-operation with the Institute of Atomic Energy in Otwock-Swierk, Poland on 25-29 May 1987. A separate abstract was prepared for each of these 20 technical papers. Refs, figs and tabs

  16. Accuracy of radiography and computed tomography in the diagnosis of distal radio-ulnar joint congruity in rheumatoid hands

    Yamaguchi, Michio; Kawakita, Hirofumi; Ogawa, Ryokei; Minamikawa, Yoshitaka; Kojima, Shin; Morimoto, Tadanobu; Yakura, Hisayoshi; Iida, Hirosuke

    1988-01-01

    We investigated the accuracy of radiography and computed tomography in the diagnosis of distal radio-ulnar joint (DRUJ) congruity in 10 healthy hands and 84 rheumatoid hands. Operated-on joints were excluded from this series. The CT study of DRUJ was done in positions of 90 deg, 70 deg, 45 deg, 20 deg and 0 deg in pronation and supination of the forearm. The radiographic study was done of the lateral view of the wrist with the forearm in neutral rotation, and of the P-A view with the forearm in full pronation. The evaluation was done with Mino's and Snook's criteria. All computed tomograms showed good congruity in the 10 healthy hands, so we evaluated radiograms using these results. In healthy hands, the accuracy of the lateral radiograms was 60 % and of the P-A view ones' 80 %. In the computed tomograms, good congruity was noted in 29 joints, subluxation in 57 joints and dislocation in no joints in 84 rheumatoid hands clinically diagnosed as having DRUJ incongruity. The accuracy of the lateral view radiograms was 60.5 % and of the P-A view ones' 35.7 %. Evaluation of the P-A view radiogram was impossible in 18.9 % due to bony destruction of the ulnar styloid process in RA. In the lateral view radiograms of 23 joints which showed subluxation in natural rotation by computed tomography, subluxation was noted in 11 joints, good congruity in 8 joints and dislocation in 4 joints. This study suggests that as the radiographic evaluation of DRUJ incongruity is difficult in rheumatoid hands because of severe bony and articular destruction, computed tomography is necessary for the diagnosis of DRUJ subluxation.

  17. The accuracy of radiography and computed tomography in the diagnosis of distal radio-ulnar joint congruity in rheumatoid hands

    We investigated the accuracy of radiography and computed tomography in the diagnosis of distal radio-ulnar joint (DRUJ) congruity in 10 healthy hands and 84 rheumatoid hands. Operated-on joints were excluded from this series. The CT study of DRUJ was done in positions of 90 deg, 70 deg, 45 deg, 20 deg and 0 deg in pronation and supination of the forearm. The radiographic study was done of the lateral view of the wrist with the forearm in neutral rotation, and of the P-A view with the forearm in full pronation. The evaluation was done with Mino's and Snook's criteria. All computed tomograms showed good congruity in the 10 healthy hands, so we evaluated radiograms using these results. In healthy hands, the accuracy of the lateral radiograms was 60 % and of the P-A view ones' 80 %. In the computed tomograms, good congruity was noted in 29 joints, subluxation in 57 joints and dislocation in no joints in 84 rheumatoid hands clinically diagnosed as having DRUJ incongruity. The accuracy of the lateral view radiograms was 60.5 % and of the P-A view ones' 35.7 %. Evaluation of the P-A view radiogram was impossible in 18.9 % due to bony destruction of the ulnar styloid process in RA. In the lateral view radiograms of 23 joints which showed subluxation in natural rotation by computed tomography, subluxation was noted in 11 joints, good congruity in 8 joints and dislocation in 4 joints. This study suggests that as the radiographic evaluation of DRUJ incongruity is difficult in rheumatoid hands because of severe bony and articular destruction, computed tomography is necessary for the diagnosis of DRUJ subluxation. (author)

  18. Use of cost benefit analysis in the field of industrial radiography

    Over the past decade NRPB has had a program of work on the development of cost benefit analysis (CBA) techniques in the optimisation of radiological protection. A provisional framework for including suggestions for assigning a value to unit collective dose was published for consultation in 1981/82 and after various interim statements this process culminated in formal advice in 1986. As part of this work, and as part of a project for the Commission of the European Communities (CEC) the NRPB has carried out a number of case studies to demonstrate the practical implementation of ALARA or optimisation of protection using CBA. These techniques, used in conjunction with ALARA audits, are now in general use in the NRPB's Radiation Protection Advisor Service. They have been used for a variety of medical and industrial situations, but mainly in industrial radiography as this is the part of the non-nuclear sector where occupational exposure problems predominate. Three cases are presented as representative examples

  19. Computer-aided diagnosis for the detection of the pulmonary nodules on digital chest radiography in lung cancer screening

    Objective: To evaluate the value of computer-aided detection (CAD) system for pulmonary nodule detection using digital chest radiography in lung cancer screening. Methods: One hundred consecutive digital chest radiographs from 6280 outpatients for lung cancer screening were independently reviewed by a thoracic radiologist and a computer-aided pulmonary nodule detection system. The radiographs were also reviewed by two experienced thoracic radiologists and the true nodules confirmed by two radiologists with reference to the CT images were marked and stored as a gold standard in the CAD system. The sensitivity and false positive of the radiologist and the CAD system for the detection of nodules on digital chest radiographs were compared. Results: Ninety-five and 304 nodules were identified by radiologist and the CAD system, respectively. Of 134 nodules marked as true nodules by experienced radiologists, 82 (61.2%) and 105 (78.4%) nodules were identified by the radiologist and the CAD, respectively. The radiologist missed 35 true nodules which were only detected by CAD. The CAD system missed 10 true nodules which were only detected by radiologist. One hundred and twelve (83.6%) nodules were identified by radiologist with the CAD system. One hundred and ninety-nine nodules identified by CAD were false-positive with a rate of 2.0 (199/100) per case. Conclusion: Combining review of digital radiographs by radiologist with CAD system can improve the detection of pulmonary nodules in lung cancer screening. (authors)

  20. Computational Analysis of Behavior.

    Egnor, S E Roian; Branson, Kristin

    2016-07-01

    In this review, we discuss the emerging field of computational behavioral analysis-the use of modern methods from computer science and engineering to quantitatively measure animal behavior. We discuss aspects of experiment design important to both obtaining biologically relevant behavioral data and enabling the use of machine vision and learning techniques for automation. These two goals are often in conflict. Restraining or restricting the environment of the animal can simplify automatic behavior quantification, but it can also degrade the quality or alter important aspects of behavior. To enable biologists to design experiments to obtain better behavioral measurements, and computer scientists to pinpoint fruitful directions for algorithm improvement, we review known effects of artificial manipulation of the animal on behavior. We also review machine vision and learning techniques for tracking, feature extraction, automated behavior classification, and automated behavior discovery, the assumptions they make, and the types of data they work best with. PMID:27090952

  1. Documented Safety Analysis Addendum for the Neutron Radiography Reactor Facility Core Conversion

    Boyd D. Christensen

    2009-05-01

    The Neutron Radiography Reactor Facility (NRAD) is a Training, Research, Isotope Production, General Atomics (TRIGA) reactor which was installed in the Idaho National Laboratory (INL) Hot Fuels Examination Facility (HFEF) at the Materials and Fuels Complex (MFC) in the mid 1970s. The facility provides researchers the capability to examine both irradiated and non-irradiated materials in support of reactor fuel and components programs through non-destructive neutron radiography examination. The facility has been used in the past as one facet of a suite of reactor fuels and component examination facilities available to researchers at the INL and throughout the DOE complex. The facility has also served various commercial research activities in addition to the DOE research and development support. The reactor was initially constructed using Fuel Lifetime Improvement Program (FLIP)- type highly enriched uranium (HEU) fuel obtained from the dismantled Puerto Rico Nuclear Center (PRNC) reactor. In accordance with international non-proliferation agreements, the NRAD core will be converted to a low enriched uranium (LEU) fuel and will continue to utilize the PRNC control rods, control rod drives, startup source, and instrument console as was previously used with the HEU core. The existing NRAD Safety Analysis Report (SAR) was created and maintained in the preferred format of the day, combining sections of both DOE-STD-3009 and Nuclear Regulatory Commission Regulatory Guide 1.70. An addendum was developed to cover the refueling and reactor operation with the LEU core. This addendum follows the existing SAR format combining required formats from both the DOE and NRC. This paper discusses the project to successfully write a compliant and approved addendum to the existing safety basis documents.

  2. Digital radiography vs conventional radiography - a comparison along with its image quality and benefits

    In digital radiography, information is represented in the form of discrete units, i.e., numbers, and involve the use of computers, whereas in conventional radiography, information is represented in analog or continuous form rather than in discrete fashion

  3. Changes of radiation dose and image quality due to additional filtration material in computed radiography

    Filter absorbs low-energy X-ray to increase the average energy and reduces patient exposure dose. This study investigates if the materials of Mo and W could be used for the digital imaging device CR by conducting image assessment and dose measurement of SNR, FOM and histogram. In addition, measurement of beam quality was conducted depending on the material of the filter, and at the same time, a proper combination of filters was examined depending on the change in tube voltage (kVp). In regard to entrance skin dose, Mo filter showed the dose reduction by 42∼56%, compared to Cu filter. Moreover, Mo filter showed higher transmission dose by around 1.5 times than that of Cu filter. In image assessment, it was found that W was unsuitable to be used as a filter, whereas Mo could be used as a filter to reduce dose without decline in image quality at the tube voltage of 80 kVp or higher. As tube voltage increased, 2.0 mm Al+0.1 mm Mo almost had a similar histogram width to that of 2.0 mm Al+0.2 mm Cu. Therefore, Mo filter can be used at relatively high tube voltage of 80 kVp, 100 kVp and 120 kVp. The SNR of 2.0 mm Al+0.1 mm Mo did not show any significant difference from those of 2.0 mm Al+0.2 mm Cu and 2.0 mm Al+0.1 mm Cu. As a result, if Mo filter is used to replace Cu filter in general radiography, where 80 kVp or higher is used for digital radiation image, patient exposure dose can be reduced significantly without decline in image quality, compared to Cu filter. Therefore, it is believed that Mo filter can be applied to chest X-ray and high tube voltage X-ray in actual clinical practice

  4. Computational Music Analysis

    2016-01-01

    This book provides an in-depth introduction and overview of current research in computational music analysis. Its seventeen chapters, written by leading researchers, collectively represent the diversity as well as the technical and philosophical sophistication of the work being done today in this intensely interdisciplinary field. A broad range of approaches are presented, employing techniques originating in disciplines such as linguistics, information theory, information retrieval, pattern r...

  5. Radiography – How do students understand the concept of radiography?

    Background: Radiography as a concept has mainly been associated with the functional role of the radiographer. The concept has been studied from a theoretical point of view. However, there is a lack of a theoretical foundation and research on the actual substance of the term radiography used in education. It is therefore important to undertake an investigation in order to determine how students after three years education understand the subject of radiography. Aim: The aim of this study was to analyse how students in the Swedish radiographers' degree program understand the concept of radiography. Method: A concept analysis was made according to the hybrid model, which combines theoretical, fieldwork and analytical phases. A summative content analysis was used to identify the number and content of statements. The empirical data were collected from questionnaires answered by radiography students at four universities in Sweden. Findings: All radiography students' exemplified radiography with statements related to the practical level although some of them also identified radiography at an abstract level, as a subject within a discipline. The attribute ‘An interdisciplinary area of knowledge’ emerged, which is an attribute on the abstract level. The practical level was described by four attributes: Mastering Medical Imaging’, ‘To accomplish images for diagnosis and interventions’, ‘Creating a caring environment’ and ‘Enabling fruitful encounters’. Conclusion: The hybrid model used was a versatile model of concept development. The results of this study have increased the understanding of what characterizes the concept of radiography in a Swedish context. - Highlights: • This concept analysis of radiography was undertaken according to a hybrid model. • In radiography humanistic aspects are emphasized, a shift from the technological perspective. • The attributes demonstrate the essence and interdisciplinary nature of radiography. • This

  6. Detectability of simulated pulmonary nodules on chest radiographs: Comparison between irradiation side sampling indirect flat-panel detector and computed radiography

    Objective: To compare the detectability of simulated pulmonary nodules on chest radiographs between an irradiation side sampling indirect flat-panel detector (ISS-FPD) and computed radiography (CR). Materials and methods: This study was an observer performance study. Simulated pulmonary nodules of 8 mm in diameter were superimposed on an anthropomorphic chest phantom. Chest radiographs were acquired under 2 exposure levels (4 and 3.2 mAs) with the ISS-FPD and the CR. Six thoracic radiologists evaluated all 40 images (10 patterns × 2 different exposure doses × 2 different systems) for the presence or absence of a lesion over each of 12 defined areas on a 3-megapixel monochrome liquid-crystal display. Receiver operating characteristic (ROC) curves were obtained for observation in predefined 480 areas. A jackknife method was used for statistical analysis. Differences with a P value of <0.05 were considered significant. Results: The analysis of the observer detection of simulated pulmonary nodules showed larger areas under the ROC curve (AUC) by the ISS-FPD than by the CR. There was a statistically significant difference between the two systems at 3.2 mAs (P = 0.0330). Conclusion: The ISS-FPD was superior to the CR for the detection of simulated pulmonary nodules at 3.2 mAs

  7. Fundamental analysis and algorithms for development of a mobile fast-scan lateral migration radiography system

    Su, Zhong

    Lateral migration radiography (LMR) is a unique x-ray Compton backscatter imaging (CBI) technique to image surface and subsurface, or internal structure of an object. An x-ray pencil beam scans the interrogated area and the backscattered photons are registered by detectors which have varying degrees of collimation. In early LMR applications, either the LMR systems or the imaged objects are moved on a rectangular grid, and at each node, the systems register backscattered photon energy deposition as pixel intensity in acquired images. The mechanical movement of the system or objects from pixel to pixel causes prolonged image scan time with a high percentage of system dead time. To avoid this drawback, a particular x-ray beam formation technique is proposed and analyzed. A corresponding mobile, fast-scan LMR system is designed, fabricated and tested. The results show a two orders-of-magnitude reduction in image scan time compared with those of previous systems. The x-ray beam formation technique, based on a rotating collimator in the LMR system, implements surface line scan by sampling an x-ray fan beam. This rotating collimator yields unique imaging effects compared to those for an x-ray beam with fixed collimation and perpendicular incidence: (1) the speed of the x-ray beam spot on the scanned surface is not uniform; (2) constant movement of the x-ray beam spot changes the resolution in the image raster direction; (3) x-ray beam spot size changes with location on the scanned surface; (4) the object image shows a squeezed effect in the raster scan direction; (5) under a uniform background, the Compton scatter angular distribution causes the x-ray backscatter field to be stronger, when the x-ray beam has greater incidence angle; and (6) the x-ray illumination spot trace on the scanned surface is skewed. The physics generating these effects is analyzed with Monte Carlo computer simulations and/or measurements. Image acquisition and image processing algorithms are

  8. A case of complex odontoma in a horse - clinical signs, radiography, ultrasonography and computer tomography

    The clinical signs, diagnosis and pathology of an adult horse with a complex odontoma are described. Computer tomography was shown to be a new diagnostic technique with outstanding potential in the investigation of diseases of the equine head

  9. A comparative study of adult patient doses in film screen and computed radiography in some Sudanese hospitals

    A study was performed to compare adult patient doses in film screen (FS) and computed radiography (CR) diagnostic X-ray examinations in some hospitals in Sudan over a period of 1 y; during this period of time, the CR systems were introduced to replace FS systems. Radiation doses were estimated for 354 patients in five hospitals (two FS units and three CR units). Entrance surface air kerma (ESAK) was estimated from incident air kerma using patient exposure parameters and tube output. Dose calculations were performed using CALDOSE X 3.5 Monte Carlo-based software. In FS, third quartile of ESAK values for skull PA, skull LAT, chest PA, pelvis AP, lumbar spine AP and lumbar spine LAT were 1.5, 1.3, 0.3, 1.9, 2.8 and 5.9 mGy, respectively, while in CR, third quartile of ESAK values for the same examinations were 2.7, 1.7, 0.18, 1.7, 3.2 and 10.8 mGy, respectively. Comparable ESAK values were presented in FS and CR units. The results are important for future dose optimisation and setting national diagnostic reference levels. (authors)

  10. Comparative examinations of serum pepsinogen I, II and gastric area using computed radiography in the atrophic gastritis

    Tatsu, Yoshimitsu; Ogura, Yasuharu; Yamazaki, Kouichi [Osaka Medical Coll., Takatsuki (Japan)] [and others

    1995-11-01

    The relationship between serum PG I, PG II levels and extent of atrophic gastritis was examined. The subjects were 64 patients (male: 32, female: 32, 51.9 years old on average) with established diagnosis of either atrophic gastritis or normal. In the X-ray gastric examination, Fuji Computed Radiography (FCR) was used to obtain clear-cut images of the gastric area. Concerning the serum PG I level, patients in the group with atrophic gastritis showed lower levels than those of the people in the group with no atrophic change, but the variation was wide, and no definite tendency was seen in the relationship between the atrophic change and the serum PG I levels. Concerning the serum PG II level, as the atrophic change progresses, the serum PG II level tended to increase gradually. A significant reduction in the PG I/II ratio was seen in the group with atrophic changes (p<0.01) in comparison with the group with no atrophic changes, and the PG I/II value tended to decrease. In conclusion, as a relationship between the atrophic change and the serum PG levels had a wide variation, we considered it to be difficult to understand the presence and extent of the atrophic gastritis by measuring serum PG levels. (author).

  11. Comparative examinations of serum pepsinogen I, II and gastric area using computed radiography in the atrophic gastritis

    The relationship between serum PG I, PG II levels and extent of atrophic gastritis was examined. The subjects were 64 patients (male: 32, female: 32, 51.9 years old on average) with established diagnosis of either atrophic gastritis or normal. In the X-ray gastric examination, Fuji Computed Radiography (FCR) was used to obtain clear-cut images of the gastric area. Concerning the serum PG I level, patients in the group with atrophic gastritis showed lower levels than those of the people in the group with no atrophic change, but the variation was wide, and no definite tendency was seen in the relationship between the atrophic change and the serum PG I levels. Concerning the serum PG II level, as the atrophic change progresses, the serum PG II level tended to increase gradually. A significant reduction in the PG I/II ratio was seen in the group with atrophic changes (p<0.01) in comparison with the group with no atrophic changes, and the PG I/II value tended to decrease. In conclusion, as a relationship between the atrophic change and the serum PG levels had a wide variation, we considered it to be difficult to understand the presence and extent of the atrophic gastritis by measuring serum PG levels. (author)

  12. Configuration of automatic exposure control on mammography units for computed radiography to match patient dose of screen film systems

    Yang, Chang-Ying Joseph; Huang, Weidong

    2009-02-01

    Computed radiography (CR) is considered a drop-in addition or replacement for traditional screen-film (SF) systems in digital mammography. Unlike other technologies, CR has the advantage of being compatible with existing mammography units. One of the challenges, however, is to properly configure the automatic exposure control (AEC) on existing mammography units for CR use. Unlike analogue systems, the capture and display of digital CR images is decoupled. The function of AEC is changed from ensuring proper and consistent optical density of the captured image on film to balancing image quality with patient dose needed for CR. One of the preferences when acquiring CR images under AEC is to use the same patient dose as SF systems. The challenge is whether the existing AEC design and calibration process-most of them proprietary from the X-ray systems manufacturers and tailored specifically for SF response properties-can be adapted for CR cassettes, in order to compensate for their response and attenuation differences. This paper describes the methods for configuring the AEC of three different mammography units models to match the patient dose used for CR with those that are used for a KODAK MIN-R 2000 SF System. Based on phantom test results, these methods provide the dose level under AEC for the CR systems to match with the dose of SF systems. These methods can be used in clinical environments that require the acquisition of CR images under AEC at the same dose levels as those used for SF systems.

  13. Comparison of Computed Tomography and Chest Radiography in the Detection of Rib Fractures in Abused Infants

    Wootton-Gorges, Sandra L.; Stein-Wexler, Rebecca; Walton, John W.; Rosas, Angela J.; Coulter, Kevin P.; Rogers, Kristen K.

    2008-01-01

    Purpose: Chest radiographs (CXR) are the standard method for evaluating rib fractures in abused infants. Computed tomography (CT) is a sensitive method to detect rib fractures. The purpose of this study was to compare CT and CXR in the evaluation of rib fractures in abused infants. Methods: This retrospective study included all 12 abused infants…

  14. Comparison of panoramic radiography and cone beam computed tomography for assessing the relationship between the maxillary sinus floor and maxillary molars

    This study compared panoramic radiography and cone beam computed tomography (CBCT) for evaluating the relationship between the maxillary sinus floor and the roots of maxillary molars. Paired panoramic radiographs and CBCT images from 97 subjects were analysed. This analysis classified 388 maxillary molars according to their relationship to the maxillary sinus floor on panoramic radiograph and CBCT. Correlations between these two radiographic techniques were examined. Maxillary molar roots that were separate from the sinus floor showed the same classification in 100% of the cases when using these two imaging techniques. The corresponding percentage for such roots that were in contact with the sinus floor was 75%. When roots overlapped the maxillary sinus floor on panoramic radiographs, only 26.4% of maxillary first molars and 60.0% of second molars showed protrusion of roots into the sinus with CBCT. The results of the study suggest that roots projecting into the sinus on panoramic radiographs require a three-dimensional image in order to analyze the proximity of their apex to the sinus floor.

  15. Shielding Benchmark Computational Analysis

    Hunter, H.T.; Slater, C.O.; Holland, L.B.; Tracz, G.; Marshall, W.J.; Parsons, J.L.

    2000-09-17

    Over the past several decades, nuclear science has relied on experimental research to verify and validate information about shielding nuclear radiation for a variety of applications. These benchmarks are compared with results from computer code models and are useful for the development of more accurate cross-section libraries, computer code development of radiation transport modeling, and building accurate tests for miniature shielding mockups of new nuclear facilities. When documenting measurements, one must describe many parts of the experimental results to allow a complete computational analysis. Both old and new benchmark experiments, by any definition, must provide a sound basis for modeling more complex geometries required for quality assurance and cost savings in nuclear project development. Benchmarks may involve one or many materials and thicknesses, types of sources, and measurement techniques. In this paper the benchmark experiments of varying complexity are chosen to study the transport properties of some popular materials and thicknesses. These were analyzed using three-dimensional (3-D) models and continuous energy libraries of MCNP4B2, a Monte Carlo code developed at Los Alamos National Laboratory, New Mexico. A shielding benchmark library provided the experimental data and allowed a wide range of choices for source, geometry, and measurement data. The experimental data had often been used in previous analyses by reputable groups such as the Cross Section Evaluation Working Group (CSEWG) and the Organization for Economic Cooperation and Development/Nuclear Energy Agency Nuclear Science Committee (OECD/NEANSC).

  16. Time resolved analysis of water drainage in porous asphalt concrete using neutron radiography.

    Poulikakos, L D; Sedighi Gilani, M; Derome, D; Jerjen, I; Vontobel, P

    2013-07-01

    Porous asphalt as a road surface layer controls aquaplaning as rain water can drain through its highly porous structure. The process of water drainage through this permeable layer is studied using neutron radiography. Time-resolved water configuration and distribution within the porous structure are reported. It is shown that radiography depicts the process of liquid water transport within the complex geometry of porous asphalt, capturing water films, filled dead end pores and water islands. PMID:23500651

  17. Diagnostic value of computed tomography, radiography and ultrasonography in metacarpophalangeal joint disorders in horses

    V.M.V. Machado; A.C.S. Aguiar; G.F. Viana; N.O. Crosignani; J.N.P. Puoli Filho

    2016-01-01

    In modern society the work and athletic performance of horses has led to a very important animal production sector in which Brazil possesses the third largest horse stock. Among all equine lesions described, metacarpophalangeal (fetlock) joint lesions are considered one of the main causes of lameness. Consequently, there is a need to improve the understanding and diagnosis of these injuries. The most efficient imaging diagnostic methods for the fetlock region are computed tomography, radiogra...

  18. X-Ray Digital Radiography and Computed Tomography Characterization of Targets

    The summary of this report is: (1) The Xradia Micro XCT and LLNL CCAT x-ray systems are used to nondestructively characterize a variety of materials, assemblies, and reference standard components; (2) The digital radiograph (DR) and computed tomography (CT) image data may be used for metrology, quality control, and defect detection; and (3) The ability to detect and characterize imperfections leads to improvements in the manufacturing processes for assemblies

  19. Broadening the radiography spectrum

    The text discuses the mammography in breast screening and evaluation of breast cancer; Small parts ultrasounds at plaza imaging solutions; role of a Radiographer in mammography-new perspective; Medical imaging education in africa; Caring for the paediatric patient as to broaden radiotherapy spectrum; Problems and challenges in care for children undergoing radiotherapy; Paediatric radiotherapy, management and side effects; The principles of pattern recognition of skeletal structures; the place of distance learning education in broadening the radiography spectrum; the curriculum and budgeting image; sonographer's guide; Computed radiography- X-Ray with vision; digital Radiography in Kenya today; Particle Therapy at Ithemba Labs; The role of lung perfusion and ventilation study in the evaluation of the pulmonary embolism and lastly, an overview of Head and neck treatment at Kenyatta National hospital radiotherapy

  20. Physical and Clinical Comparison between a Screen-Film System and a Dual-Side Reading Mammography-Dedicated Computed Radiography System

    Background: Digital mammography systems, thanks to a physical performance better than conventional screen-film units, have the potential of reducing the dose to patients, without decreasing the diagnostic accuracy. Purpose: To achieve a physical and clinical comparison between two systems: a screen-film plate and a dual-side computed radiography system (CRM; FUJIFILM FCR 5000 MA). Material and Methods: A unique feature of the FCR 5000 MA system is that it has a clear support medium, allowing light emitted during the scanning process to be detected on the 'back' of the storage phosphor plate, considerably improving the system's efficiency. The system's physical performance was tested by means of a quantitative analysis, with calculation of the modulation transfer function, detective quantum efficiency, and contrast-detail analysis; subsequently, the results were compared with those achieved using a screen-film system (SFM; Eastmann Kodak MinR-MinR 2000). A receiver operating characteristic (ROC) analysis was then performed on 120 paired clinical images obtained in a craniocaudal projection with the conventional SFM system under standard exposure conditions and also with the CRM system working with a dose reduced by 35% (average breast thickness: 4.3 cm; mean glandular dose: 1.45 mGy). CRM clinical images were interpreted both in hard copy and in soft copy. Results: The ROC analysis revealed that the performances of the two systems (SFM and CRM with reduced dose) were similar (P>0.05): the diagnostic accuracy of the two systems, when valued in terms of the area underneath the ROC curve, was found to be 0.74 for the SFM, 0.78 for the CRM (hard copy), and 0.79 for the CRM (soft copy). Conclusion: The outcome obtained from our experiments shows that the use of the dual-side CRM system is a very good alternative to the screen-film system

  1. Industrial radiography

    Industrial radiography is a non-destructive testing (NDT) method which allows components to be examined for flaws without interfering with their usefulness. It is one of a number of inspection methods which are commonly used in industry to control the quality of manufactured products and to monitor their performance in service. Because of its involvement in organizing training courses in all the common NDT methods in regional projects in Asia and the Pacific and Latin America and the Caribbean and in many country programmes, the Agency is aware of the importance of standardizing as far as possible the syllabi and training course notes used by the many experts who are involved in presenting the training courses. IAEA-TECDOC-628 ''Training Guidelines in Non-destructive Testing'' presents syllabi which were developed by an Agency executed UNDP project in Latin America and the Caribbean taking into account the developmental work done by the International Committee for Non-destructive Testing. Experience gained from using the radiography syllabi from TECDOC-628 at national and regional radiography training courses in the Agency executed UNDP project in Asia and the Pacific (RAS/86/073) showed that some guidance needed to be given to radiography experts engaged in teaching at these courses on the material which should be covered. The IAEA/UNDP Asia and Pacific Project National NDT Coordinators therefore undertook to prepare Radiography Training Course Notes which could be used by experts to prepare lectures for Level 1,2 and 3 radiography personnel. The notes have been expanded to cover most topics in a more complete manner than that possible at a Level 1, 2 or 3 training course and can now be used as source material for NDT personnel interested in expanding their knowledge of radiography. Refs, figs and tabs

  2. Optimization of the radiological protection of patients undergoing radiography, fluoroscopy and computed tomography. Final report of a coordinated research project in Africa, Asia and eastern Europe

    Although radiography has been an established imaging modality for over a century, continuous developments have led to improvements in technique resulting in improved image quality at reduced patient dose. If one compares the technique used by Roentgen with the methods used today, one finds that a radiograph can now be obtained at a dose which is smaller by a factor of 100 or more. Nonetheless, some national surveys, particularly in the United Kingdom and in the United States of America in the 1980s and 1990s, have indicated large variations in patient doses for the same diagnostic examination, in some cases by a factor of 20 or more. This arises not only owing to the various types of equipment and accessories used by the different health care providers, but also because of operational factors. The IAEA has a statutory responsibility to establish standards for the protection of people against exposure to ionising radiation and to provide for the worldwide application of those standards. A fundamental requirement of the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (BSS), issued by the IAEA in cooperation with the FAO, ILO, WHO, PAHO and NEA, is the optimization of radiological protection of patients undergoing medical exposure. Towards its responsibility of implementation of standards and under the subprogramme of radiation safety, in 1995, the IAEA launched a coordinated research project (CRP) on radiological protection in diagnostic radiology in some countries in the Eastern European, African and Asian region. Initially, the CRP addressed radiography only and it covered wide aspects of optimisation of radiological protection. Subsequently, the scope of the CRP was extended to fluoroscopy and computed tomography (CT), but it covered primarily situation analysis of patient doses and equipment quality control. It did not cover patient dose reduction aspects in fluoroscopy and CT. The project

  3. The teaching of computer programming and digital image processing in radiography.

    Allan, G L; Zylinski, J

    1998-06-01

    The increased use of digital processing techniques in Medical Radiations imaging modalities, along with the rapid advance in information technology has resulted in a significant change in the delivery of radiographic teaching programs. This paper details a methodology used to concurrently educate radiographers in both computer programming and image processing. The students learn to program in visual basic applications (VBA), and the programming skills are contextualised by requiring the students to write a digital subtraction angiography (DSA) package. Program code generation and image presentation interface is undertaken by the spreadsheet Microsoft Excel. The user-friendly nature of this common interface enables all students to readily begin program creation. The teaching of programming and image processing skills by this method may be readily generalised to other vocational fields where digital image manipulation is a professional requirement. PMID:9726504

  4. The application of the Fuji computed radiography system for the diagnosis of pneumoconiosis, 2

    This is the second part of the project shown in the title. Here we developed several image processing procedures to extract quantitative features for diagnostic aid, and to classify sizes and types of pneumoconiosis from chest X-ray films automatically. Those procedures include automated extraction of small round opacities, calculation of the density of opacities, and classification of a given film into two major categories (normal or abnormal), or into more detailed categories such as the type 0, 1, 2, and 3, and the type p, q, and r. Recognition rate was about 60 to 75%, depending on features and sample films used in the experiment. Methods to generate a sketch of a chest X-ray image by computer are also presented. (author)

  5. Malignant diffuse pleural mesothelioma: Comparison between computed tomography and conventional plain radiography of the thorax

    The rate of incidence of malignant pleural mesothelioma is increasing although diagnosis of this disease may be very difficult. Computed tomography examinations and conventional chest X-rays of 30 patients with malignant pleural mesothelioma were reviewed independently, to evaluate the role of both modalities. CT offered the following advantages over conventional chest X-ray examinations: Ct was more sensitive in detecting the smooth and nodular changes of malignant pleural mesothelioma, especially at the diaphragm and lower parts of the thorax, tumours could be better demonstrated at the pericardium and in the greater fissure, in some cases, where chest films showed just abnormal widening of the mediastinum, CT could differentiate between tumour involvement of the mediastinal pleura and local invasion of the mediastinum by the tumour CT was more effective in detecting pleural calcifications and thickening of the contralateral pleura. CT proves more accurate in assessing the extent of the disease, and gives additional diagnostic help. (orig.)

  6. Radiography, computed tomography and magnetic resonance imaging at 0.5 Tesla of mechanically inducedosteoarthritis in rabbit knees

    Torelli S.R.

    2004-01-01

    Full Text Available In the present experimental study we assessed induced osteoarthritis data in rabbits, compared three diagnostic methods, i.e., radiography (XR, computed tomography (CT and magnetic resonance imaging (MRI, and correlated the imaging findings with those obtained by macroscopic evaluation. Ten young female rabbits of the Norfolk breed were used. Seven rabbits had the right knee immobilized in extension for a period of 12 weeks (immobilized group, and three others did not have a limb immobilized and were maintained under the same conditions (control group. Alterations observed by XR, CT and MRI after the period of immobilization were osteophytes, osteochondral lesions, increase and decrease of joint space, all of them present both in the immobilized and non-immobilized contralateral limbs. However, a significantly higher score was obtained for the immobilized limbs (XT: P = 0.016, CT: P = 0.031, MRI: P = 0.0156. All imaging methods were able to detect osteoarthritis changes after the 12 weeks of immobilization. Macroscopic evaluation identified increased thickening of joint capsule, proliferative and connective tissue in the femoropatellar joint, and irregularities of articular cartilage, especially in immobilized knees. The differences among XR, CT and MRI were not statistically significant for the immobilized knees. However, MRI using a 0.5 Tesla scanner was statistically different from CT and XR for the non-immobilized contralateral knees. We conclude that the three methods detected osteoarthritis lesions in rabbit knees, but MRI was less sensitive than XR and CT in detecting lesions compatible with initial osteoarthritis. Since none of the techniques revealed all the lesions, it is important to use all methods to establish an accurate diagnosis.

  7. Pelvic crush fractures in survivors of the Sichuan earthquake evaluated by digital radiography and multidetector computed tomography

    To investigate the profile of pelvic crush fractures in earthquake victims on digital radiography (DR) and multidetector computed tomography (MDCT). One hundred and sixty-seven consecutive survivors of the 2008 Sichuan earthquake with pelvic crush fractures classified into types according to the Tile classification system, entered our study. One hundred and thirty-nine, and 28 patients underwent DR and MDCT scans, respectively. Data were reviewed retrospectively focusing on anatomical sites, numbers, and classification of pelvic ring fractures. Pelvic fractures occurred in the pubis in 88 patients (52.7%), in other pelvic bones in 32 (19.16%), and in both the pubis and other pelvic bones in 47 (28.14%). Pubic fractures were more common than fractures of other pelvic bones, and involvement of bilateral pubis was more common than that of the left or right pubis (all p < 0.05). As for the numbers of pelvic bones involved, multiple fractures occurred in 48.52% patients (81 out of 167) composed predominantly of fractures of two bones in 58.02% (47 out of 81), and were seen more often in bilateral pubis than in any other pelvic bones (p < 0.05). Regarding classifications of pelvic ring fractures, they were Type A in 31 patients (18.56%); Type B in 72 (43.11%), predominantly Type B2 in 26 (15.58%) and Type B3 in 28 (16.77%); and Type C in 64 (38.32%), predominantly Type C3 in 40 (23.95%). Pelvic crush fractures particularly including multiple pelvic fractures, occurring predominantly in bilateral pubis, and composed of Type C3 followed by Type B3 and Type B2, could be considered to be the profile of pelvic crush fractures in an earthquake. (orig.)

  8. Radiography, computed tomography and magnetic resonance imaging at 0.5 Tesla of mechanically induced osteoarthritis in rabbit knees

    Torelli, S.R. [UNESP, Botucatu, SP (Brazil). Faculdade de Medicina Veterinaria e Zootecnia. Programa de Pos-graduacao em Medicina Veterinaria; Rahal, R.S. [UNESP, Botucatu, SP (Brazil). Faculdade de Medicina Veterinaria e Zootecnia. Dept. de Cirurgia e Anestesiologia Veterinaria]. E-mail: sheilacr@fmvz.unesp.br; Volpi, R.S. [UNESP, Botucatu, SP (Brazil). Faculdade de Medicina. Dept. de Cirurgia e Ortopedia; Yamashita, S. [UNESP, Botucatu, SP (Brazil). Faculdade de Medicina. Dept. de Doencas Tropicais e Diagnostico por Imagens; Mamprim, M.J. [UNESP, Botucatu, SP (Brazil). Faculdade de Medicina Veterinaria e Zootecnia. Dept. de Reproducao Animal e Radiologia; Crocci, A.J. [UNESP, Botucatu, SP (Brazil). Inst. de Biociencias. Dept. de Bioestatistica

    2004-04-01

    In the present experimental study we assessed induced osteoarthritis data in rabbits, compared three diagnostic methods, i.e., radiography (XR), computed tomography (CT) and magnetic resonance imaging (MRI), and correlated the imaging findings with those obtained by macroscopic evaluation. Ten young female rabbits of the Norfolk breed were used. Seven rabbits had the right knee immobilized in extension for a period of 12 weeks (immobilized group), and three others did not have a limb immobilized and were maintained under the same conditions (control group). Alterations observed by XR, CT and MRI after the period of immobilization were osteophytes, osteochondral lesions, increase and decrease of joint space, all of them present both in the immobilized and non-immobilized contralateral limbs. However, a significantly higher score was obtained for the immobilized limbs (XT: P = 0.016, CT: P 0.031, MRI: P = 0.0156). All imaging methods were able to detect osteoarthritis changes after the 12 weeks of immobilization. Macroscopic evaluation identified increased thickening of joint capsule, proliferative and connective tissue in the femoropatellar joint, and irregularities of articular cartilage, especially in immobilized knees. The differences among XR, CT and MRI were not statistically significant for the immobilized knees. However, MRI using a 0.5 Tesla scanner was statistically different from CT and XR for the non-immobilized contralateral knees. We conclude that the three methods detected osteoarthritis lesions in rabbit knees, but MRI was less sensitive than XR and CT in detecting lesions compatible with initial osteoarthritis. Since none of the techniques revealed all the lesions, it is important to use all methods to establish an accurate diagnosis. (author)

  9. Application of off-line image processing for optimization in chest computed radiography using a low cost system.

    Muhogora, Wilbroad E; Msaki, Peter; Padovani, Renato

    2015-01-01

     The objective of this study was to improve the visibility of anatomical details by applying off-line postimage processing in chest computed radiography (CR). Four spatial domain-based external image processing techniques were developed by using MATLAB software version 7.0.0.19920 (R14) and image processing tools. The developed techniques were implemented to sample images and their visual appearances confirmed by two consultant radiologists to be clinically adequate. The techniques were then applied to 200 chest clinical images and randomized with other 100 images previously processed online. These 300 images were presented to three experienced radiologists for image quality assessment using standard quality criteria. The mean and ranges of the average scores for three radiologists were characterized for each of the developed technique and imaging system. The Mann-Whitney U-test was used to test the difference of details visibility between the images processed using each of the developed techniques and the corresponding images processed using default algorithms. The results show that the visibility of anatomical features improved significantly (0.005 ≤ p ≤ 0.02) with combinations of intensity values adjustment and/or spatial linear filtering techniques for images acquired using 60 ≤ kVp ≤ 70. However, there was no improvement for images acquired using 102 ≤ kVp ≤ 107 (0.127 ≤ p ≤ 0.48). In conclusion, the use of external image processing for optimization can be effective in chest CR, but should be implemented in consultations with the radiologists. PMID:26103165

  10. Radiography, computed tomography and magnetic resonance imaging at 0.5 Tesla of mechanically induced osteoarthritis in rabbit knees

    In the present experimental study we assessed induced osteoarthritis data in rabbits, compared three diagnostic methods, i.e., radiography (XR), computed tomography (CT) and magnetic resonance imaging (MRI), and correlated the imaging findings with those obtained by macroscopic evaluation. Ten young female rabbits of the Norfolk breed were used. Seven rabbits had the right knee immobilized in extension for a period of 12 weeks (immobilized group), and three others did not have a limb immobilized and were maintained under the same conditions (control group). Alterations observed by XR, CT and MRI after the period of immobilization were osteophytes, osteochondral lesions, increase and decrease of joint space, all of them present both in the immobilized and non-immobilized contralateral limbs. However, a significantly higher score was obtained for the immobilized limbs (XT: P = 0.016, CT: P 0.031, MRI: P = 0.0156). All imaging methods were able to detect osteoarthritis changes after the 12 weeks of immobilization. Macroscopic evaluation identified increased thickening of joint capsule, proliferative and connective tissue in the femoropatellar joint, and irregularities of articular cartilage, especially in immobilized knees. The differences among XR, CT and MRI were not statistically significant for the immobilized knees. However, MRI using a 0.5 Tesla scanner was statistically different from CT and XR for the non-immobilized contralateral knees. We conclude that the three methods detected osteoarthritis lesions in rabbit knees, but MRI was less sensitive than XR and CT in detecting lesions compatible with initial osteoarthritis. Since none of the techniques revealed all the lesions, it is important to use all methods to establish an accurate diagnosis. (author)

  11. COMPARISONS AMONG RADIOGRAPHY, ULTRASONOGRAPHY AND COMPUTED TOMOGRAPHY FOR EX VIVO CHARACTERIZATION OF STIFLE OSTEOARTHRITIS IN THE HORSE.

    De Lasalle, Julie; Alexander, Kate; Olive, Julien; Laverty, Sheila

    2016-09-01

    A better understanding of imaging characteristics of equine stifle osteoarthritis (OA) may allow earlier detection and improve prognosis. Objectives of this ex vivo, prospective, methods comparison study were to (1) describe the location and severity of naturally acquired OA lesions in the equine stifle using ultrasound (US), radiography (XR), computed tomography (CT), and macroscopic evaluation (ME); (2) compare the diagnostic performance of each imaging modality with ME; and (3) describe subchondral bone mineral density (BMD) in equine stifle joints with OA using CT. Radiographic, CT, and US evaluations were performed on 23 equine cadaver stifles and compared with ME. Significant associations were found between osteophyte global scores for all imaging modalities (CT, P ˂ 0.0001; XR, P = 0.005; US, P = 0.04) vs. ME osteophyte global scores. Osteophytes were detected most frequently in the medial femorotibial (MFT) joint. A specific pattern of osteophytes was observed, with a long ridge of new bone at the insertion of the MFT joint capsule cranially on the medial femoral condyle. A novel caudo-10°proximo-5°lateral-cranio-disto-medial oblique radiographic projection was helpful for detection of intercondylar osteophytes. Multiplanar CT reformatted images were helpful for characterizing all osteophytes. Osteophyte grades at most sites did not differ among modalities. Low sensitivity/specificity for subchondral bone sclerosis and flattening of femoral condyles suggested that these signs may not be reliable radiographic and CT indicators of equine stifle OA. Equine stifle OA was associated with a decrease in BMD and specific sites of focal subchondral bone resorption/cyst formation were found in some specimens. PMID:27237699

  12. MEASUREMENT OF ROOT LENGTH DENSITY IN INTACT SAMPLES USING X-RADIOGRAPHY AND IMAGE ANALYSIS

    Alain Pierret

    2011-05-01

    Full Text Available Measurement of root system attributes is of critical importance to understand and model plant growth. Root length density, the length of roots per unit volume of soil, is one of the important parameters required to understand plant performance. Measuring techniques currently in use to assess this parameter, such as for example core washing, are notoriously imprecise and labour-intensive. Roots and soil being inextricably linked, it is virtually impossible to separate them without loosing a significant amount of the root sample to be measured. This noticeably compromises the accuracy of washing techniques. For this reason, non-invasive measurement approaches are highly desirable. Here, a method based on the combination of X-radiography and image analysis is proposed as a new alternative for the measurement of root length density from intact samples. The successive steps of the method, from sampling to image acquisition are briefly described. A specific measurement algorithm, designed to account for the complex spatial arrangement of the roots within the samples is then presented and discussed in detail.

  13. Neutron radiography

    This introduction is addressed to an audience active in diverse forms of neutron source applications but not directly familiar with neutron radiography. Neutron radiography is, of course, similar to, and complementary to, radiography using x-rays. However, neutrons, being sensitive to the nuclear properties of materials, provide information fundamentally different from x-rays. For example, neutrons can penetrate many dense metals such as uranium, lead, bismuth or steel, and can reveal details of internal hydrogenous components: explosives, lubricants and gaskets. For nuclear fuel inspection neutron radiography offers the ability to penetrate dense uranium-238 and contrast the isotopes U-235 or Pu-239 and also offers the ability to discriminate against unwanted interference from gamma radiation. In addition to advantages in industrial applications, there are special situations in fields such as medical diagnostics, dentistry, agriculture and forensic science. Comprehensive accounts of applications in the field can be found in the proceedings of the world conferences on neutron radiography: USA (1981), FRANCE (1986). A third conference in this series is scheduled for May 1989 in Japan

  14. Correlation between the signal-to-noise ratio improvement factor (KSNR) and clinical image quality for chest imaging with a computed radiography system

    Moore, C. S.; Wood, T. J.; Saunderson, J. R.; Beavis, A. W.

    2015-12-01

    This work assessed the appropriateness of the signal-to-noise ratio improvement factor (KSNR) as a metric for the optimisation of computed radiography (CR) of the chest. The results of a previous study in which four experienced image evaluators graded computer simulated chest images using a visual grading analysis scoring (VGAS) scheme to quantify the benefit of using an anti-scatter grid were used for the clinical image quality measurement (number of simulated patients  =  80). The KSNR was used to calculate the improvement in physical image quality measured in a physical chest phantom. KSNR correlation with VGAS was assessed as a function of chest region (lung, spine and diaphragm/retrodiaphragm), and as a function of x-ray tube voltage in a given chest region. The correlation of the latter was determined by the Pearson correlation coefficient. VGAS and KSNR image quality metrics demonstrated no correlation in the lung region but did show correlation in the spine and diaphragm/retrodiaphragmatic regions. However, there was no correlation as a function of tube voltage in any region; a Pearson correlation coefficient (R) of  -0.93 (p  =  0.015) was found for lung, a coefficient (R) of  -0.95 (p  =  0.46) was found for spine, and a coefficient (R) of  -0.85 (p  =  0.015) was found for diaphragm. All demonstrate strong negative correlations indicating conflicting results, i.e. KSNR increases with tube voltage but VGAS decreases. Medical physicists should use the KSNR metric with caution when assessing any potential improvement in clinical chest image quality when introducing an anti-scatter grid for CR imaging, especially in the lung region. This metric may also be a limited descriptor of clinical chest image quality as a function of tube voltage when a grid is used routinely.

  15. Correlation between the signal-to-noise ratio improvement factor (KSNR) and clinical image quality for chest imaging with a computed radiography system

    This work assessed the appropriateness of the signal-to-noise ratio improvement factor (KSNR) as a metric for the optimisation of computed radiography (CR) of the chest. The results of a previous study in which four experienced image evaluators graded computer simulated chest images using a visual grading analysis scoring (VGAS) scheme to quantify the benefit of using an anti-scatter grid were used for the clinical image quality measurement (number of simulated patients  =  80). The KSNR was used to calculate the improvement in physical image quality measured in a physical chest phantom. KSNR correlation with VGAS was assessed as a function of chest region (lung, spine and diaphragm/retrodiaphragm), and as a function of x-ray tube voltage in a given chest region. The correlation of the latter was determined by the Pearson correlation coefficient. VGAS and KSNR image quality metrics demonstrated no correlation in the lung region but did show correlation in the spine and diaphragm/retrodiaphragmatic regions. However, there was no correlation as a function of tube voltage in any region; a Pearson correlation coefficient (R) of  −0.93 (p  =  0.015) was found for lung, a coefficient (R) of  −0.95 (p  =  0.46) was found for spine, and a coefficient (R) of  −0.85 (p  =  0.015) was found for diaphragm. All demonstrate strong negative correlations indicating conflicting results, i.e. KSNR increases with tube voltage but VGAS decreases. Medical physicists should use the KSNR metric with caution when assessing any potential improvement in clinical chest image quality when introducing an anti-scatter grid for CR imaging, especially in the lung region. This metric may also be a limited descriptor of clinical chest image quality as a function of tube voltage when a grid is used routinely. (paper)

  16. High energy x-ray radiography and computed tomography of bridge pins

    Bridge pins were used in the hanger assemblies for some multi-span steel bridges built prior to the 1980's, and are sometimes considered fracture critical elements of a bridge. During a test on a bridge conducted by the Federal Highway Administration (FHWA), ultrasonic field inspection results indicated that at least two pins contained cracks. Several pins were removed and selected for further examination. This provided an excellent opportunity to learn more about these pins and the application of x-ray systems at Lawrence Livermore National Laboratory (LLNL), as well as to learn more about the application of different detectors recently obtained by LLNL. Digital radiographs and computed tomography (CT) were used to characterize the bridge pins, using a LINAC x-ray source with a 9-MV bremsstrahlung spectrum. We will describe the performance of two different digital radiographic detectors. One is a detector system frequently used at LLNL consisting of a scintillator glass optically coupled to a CCD camera. The other detector is a new amorphous silicon detector recently acquired by LLNL

  17. Pulmonary infections in the late period after allogeneic bone marrow transplantation: chest radiography versus computed tomography

    Purpose: To analyze the capabilities of chest roentgenogram (CXR) and computed tomography (CT) in the evaluation of pulmonary infectious disease in the late period (>100 days) after allogeneic bone marrow transplantation (BMT). Methods: Ninety-four matched CXR and CT examinations were performed for clinical suspicion of infectious lung disease. The time gap between CXR and CT was 48 h at maximum. The image pairs were correlated with the patients' clinical course and with the results of diagnostic bronchoalveolar lavage (BAL). An unremarkable clinical course over the subsequent seven days after imaging and/or negative microbiological culture served as the basis for excluding infectious lung disease. Positive microbiological culture and/or improvement of symptoms after antibiotic therapy were considered as evidence of infectious disease. Results: The correlation with the clinical course and/or BAL revealed a significantly higher sensitivity, negative predictive value, and accuracy for CT than for CXR (89% versus 58%, P < 0.0001; 78% versus 47%, P < 0.0001; 90% versus 68%, P < 0.0001, respectively). CT was significantly more diagnostic in BAL verified fungal and bacterial infections (P < 0.05). Conclusion: CT is significantly superior to CXR in the evaluation of infectious pulmonary disease in the late phase after BMT. Therefore, an unremarkable CXR should be followed by a CT scan to reliably detect or to accurately exclude early pulmonary infection in these patients

  18. High-resolution computed tomography in silicosis: correlation with chest radiography and pulmonary function tests

    Lopes, Agnaldo Jose [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Pedro Ernesto Univ. Hospital. Dept. of Respiratory Function]. E-mail: phel.lop@uol.com.br; Mogami, Roberto; Capone, Domenico; Jansen, Jose Manoel [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). School of Medical Sciences; Tessarollo, Bernardo [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Dept. of Radiology and Diagnostic Image; Melo, Pedro Lopes de [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Inst. of Biology

    2008-05-15

    Objective: To correlate tomographic findings with pulmonary function findings, as well as to compare chest X-ray findings with high-resolution computed tomography (HRCT) findings, in patients with silicosis. Methods: A cross-sectional study was conducted in 44 non-smoking patients without a history of tuberculosis. Chest X-ray findings were classified according to the International Labour Organization recommendations. Using a semiquantitative system, the following HRCT findings were measured: the full extent of pulmonary involvement; parenchymal opacities; and emphysema. Spirometry and forced oscillation were performed. Pulmonary volumes were evaluated using the helium dilution method, and diffusing capacity of the lung for carbon monoxide was assessed. Results: Of the 44 patients studied, 41 were male. The mean age was 48.4 years. There were 4 patients who were classified as category 0 based on X-ray findings and as category 1 based on HRCT findings. Using HRCT scans, we identified progressive massive fibrosis in 33 patients, compared with only 23 patients when X-rays were used. Opacity score was found to correlate most closely with airflow, DLCO and compliance. Emphysema score correlated inversely with volume, DLCO and airflow. In this sample of patients presenting a predominance of large opacities (75% of the individuals), the deterioration of pulmonary function was associated with the extent of structural changes. Conclusions: In the early detection of silicosis and the identification of progressive massive fibrosis, HRCT scans are superior to X-rays. (author)

  19. High-resolution computed tomography in silicosis: correlation with chest radiography and pulmonary function tests

    Objective: To correlate tomographic findings with pulmonary function findings, as well as to compare chest X-ray findings with high-resolution computed tomography (HRCT) findings, in patients with silicosis. Methods: A cross-sectional study was conducted in 44 non-smoking patients without a history of tuberculosis. Chest X-ray findings were classified according to the International Labour Organization recommendations. Using a semiquantitative system, the following HRCT findings were measured: the full extent of pulmonary involvement; parenchymal opacities; and emphysema. Spirometry and forced oscillation were performed. Pulmonary volumes were evaluated using the helium dilution method, and diffusing capacity of the lung for carbon monoxide was assessed. Results: Of the 44 patients studied, 41 were male. The mean age was 48.4 years. There were 4 patients who were classified as category 0 based on X-ray findings and as category 1 based on HRCT findings. Using HRCT scans, we identified progressive massive fibrosis in 33 patients, compared with only 23 patients when X-rays were used. Opacity score was found to correlate most closely with airflow, DLCO and compliance. Emphysema score correlated inversely with volume, DLCO and airflow. In this sample of patients presenting a predominance of large opacities (75% of the individuals), the deterioration of pulmonary function was associated with the extent of structural changes. Conclusions: In the early detection of silicosis and the identification of progressive massive fibrosis, HRCT scans are superior to X-rays. (author)

  20. Computed radiography in skeletal imaging: visual assessment of compressed image quality

    To evaluate the effect of lossy image compression on skeletal images and to determine the compression ratio which does not lead to difficulties when images are interpreted for diagnostic purposes. Thirty-two computed radiographs (CR) of osteolytic bone tumors were obtained from Picture Archiving and Communication System. They were compressed to three different levels (Q factor 30, 70, 120) using the JPEG (Joint Photographic Expert Group) technique. Ninety-six pairs of uncompressed and compressed images were randomly ordered and then serially displayed on two high-resolution monitors. During a side-by-side review, three radiologists independently compared each pair of uncompressed and compressed images, and these were rated once using a five-category ordinal scale for tumor-related findings, linear structures, and soft tissues. The reviewers were then obliged to decide which image in each pair was of better quality, and finally, they were asked to evaluate the influence of image compression on diagnostic accuracy. The reviewers found no significant difference in image quality between uncompressed and compressed images with a Q factor 30. Compressed images with a Q factor of 70 or 120, however, revealed clinically relevant degradation. Among 96 observations of compressed images, 15 with a Q factor of 70 and 35 with a Q factor of 120 were considered inadequate for clinical purposes. If the JPEG technique is used, compressed CR skeletal images with a Q factor of 30 are acceptable for clinical application. Compressed images with a Q factor of 70 or 120 may, however, cause diagnostic difficulty and thus cannot be used for clinical purposes

  1. Lung Cancer Screening with Computer Aided Detection Chest Radiography: Design and Results of a Randomized, Controlled Trial

    Mazzone, Peter J.; Obuchowski, Nancy; Phillips, Michael; Risius, Barbara; Bazerbashi, Bana; Meziane, Moulay

    2013-01-01

    Introduction The sensitivity of CT based lung cancer screening for the detection of early lung cancer is balanced by the high number of benign lung nodules identified, the unknown consequences of radiation from the test, and the potential costs of a CT based screening program. CAD chest radiography may improve the sensitivity of standard chest radiography while minimizing the risks of CT based screening. Methods Study subjects were age 40–75 years with 10+ pack-years of smoking and/or an addi...

  2. Time resolved analysis of water drainage in porous asphalt concrete using neutron radiography

    Porous asphalt as a road surface layer controls aquaplaning as rain water can drain through its highly porous structure. The process of water drainage through this permeable layer is studied using neutron radiography. Time-resolved water configuration and distribution within the porous structure are reported. It is shown that radiography depicts the process of liquid water transport within the complex geometry of porous asphalt, capturing water films, filled dead end pores and water islands. - Highlights: ► The water drainage process in porous asphalt was studied using neutron radiography. ► Despite similar mix designs, different processes of water transport were established. ► Water transport within porous asphalt showed filled dead end pores and water islands

  3. Industrial radiography

    This publication is meant to be a manual for industrial radiography. As such the manual concentrates on the practical aspects, presenting existing radiographic system and techniques of operation to satisfy specified quality requirements. The manual also reviews the safety aspect of performing radiographic work. (author) systems

  4. Gamma-ray and neutron radiography for a pulsed fast neutron analysis cargo inspection system

    This paper presents the design, optimization, and characterization of a gamma-ray and neutron radiographic subsystem that was developed for the Pulsed Fast Neutron Analysis (PFNA) cargo inspection system. The PFNA inspection system uses D-D based nanosecond pulsed neutron source to produce three-dimensional elemental content images of cargo. The PFNA neutron source produces gamma rays as well as neutrons. The new radiographic subsystem measures these radiations in an array of plastic scintillators to produce gamma-ray and neutron transmission images of the cargo simultaneously with the PFNA elemental content measurement. Although the radiographic subsystem improves PFNA performance in many forms of contraband detection, it was specifically designed to detect Special Nuclear Material (SNM) in cargo containers and trucks. A feasibility study, including experiments and modeling, was performed to determine the usefulness of neutron and gamma-ray radiography in this application. The study showed that the baseline configuration was useful in cargoes up to 144 g/cm2 thick. In order to improve the subsystem performance, the source output needed to be increased. The neutron and gamma-ray yield and spectrum were measured for a variety of different beam stops. The maximum cargo thickness was increased to 180 g/cm2 by changing the source beam stop from gold to copper and by increasing the detector length to 17.0 cm. An experiment was then performed that determined a 3.5 cm radiographic resolution was adequate for SNM detection. The detector configuration and the source motion were optimized to obtain a resolution of approximately 3.5 cm using the minimal number of detectors (128) and the maximum detector diameter (5.1 cm). A prototype of the final design was built, installed, and tested, and is currently in use at the PFNA test facility. (author)

  5. Efficacy of plain radiography and computer tomography in localizing the site of pelvic arterial bleeding in trauma patients

    Background: Immediate angiography is warranted in pelvic trauma patients with suspected arterial injury (AI) in order to stop ongoing bleeding. Prior to angiography, plain pelvic radiography (PPR) and abdominopelvic computer tomography (CT) are performed to identify fracture and hematoma sites. Purpose: To investigate if PPR and CT can identify the location of AI in trauma patients undergoing angiography. Material and Methods: 95 patients with pelvic fractures on PPR (29 women, 66 men), at a mean age of 44 (9-92) years, underwent pelvic angiography for suspected AI. Fifty-six of them underwent CT additionally. Right and left anterior and posterior fractures on PPR were registered, and fracture displacement was recorded for each quadrant. Arterial blush on CT was registered, and the size of the hematoma in each region was measured in cm2. AIs were registered for anterior and posterior segments of both internal iliac arteries. Presence of fractures, arterial blush, and hematomas were correlated with AI. Results: Presence of fracture in the corresponding skeletal segment on PPR showed sensitivity and specificity of 0.86 and 0.58 posteriorly, and 0.87 and 0.44 anteriorly. The area under the curve (AUC) was 0.77 and 0.69, respectively. Fracture displacement on PPR >0.9 cm posteriorly and >1.9 cm anteriorly revealed specificity of 0.84. Sensitivities of arterial blush and hematoma on CT were 0.38 and 0.82 posteriorly, and 0.24 and 0.82 anteriorly. The specificities were 0.96 and 0.58 posteriorly, and 0.79 and 0.53 anteriorly, respectively. For hematomas, the AUC was 0.79 posteriorly and 0.75 anteriorly. Size of hematoma >22 cm2 posteriorly and >29 cm2 anteriorly revealed specificity of 0.85 and 0.86, respectively. Conclusion: CT findings of arterial blush and hematoma predicted site of arterial bleeding on pelvic angiography. Also, PPR predicted the site of bleeding using location of fracture and size of displacement. In the hemodynamically unstable patient, PPR may

  6. Neutron radiography

    The digital processing of the neutron radiography images gives the possibility for data quantification. In this case an exact relation between the measured neutron attenuation and the real macroscopic attenuation coefficient for every point of the sample is required. The assumption that the attenuation of the neutron beam through the sample is exponential is valid only in an ideal case where a monochromatic beam, non scattering sample and non background contribution are assumed. In the real case these conditions are not fulfilled and in dependence on the sample material we have more or less deviation from the exponential attenuation law. Because of the high scattering cross-sections of hydrogen (σs=80.26 barn) for thermal neutrons, the problem with the scattered neutrons at quantitative radiography investigations of hydrogenous materials (as PE, Oil, H2O, etc) is not trivial. For these strong scattering materials the neutron beam attenuation is no longer exponential and a dependence of the macroscopic attenuation coefficient on the material thickness and on the distance between the sample and the detector appears. When quantitative radiography (2 D) or tomography investigations (3 D) are performed, some image correction procedures for a description of the scattering effect are required. This thesis presents a method that can be used to enhance the neutron radiography image for objects with high scattering materials like hydrogen, carbon and other light materials. This method uses the Monte Carlo code, MCNP5, to simulate the neutron radiography process and get the flux distribution for each pixel of the image and determine the scattered neutrons distribution that causes the image blur and then subtract it from the initial image to improve its quality.

  7. Physical principles of digital radiography

    A simplified overview is given of the physical principles of digital radiography as used in X-ray transmission computed tomography and digital fluoroscopy. The advantages of the digital method over conventional radiography are pointed out. After discussing the analogue to digital conversion stage, the storage space and resolution constraints are considered as well as the resulting limitations on the maximum frame rates for picture acquisition. (U.K.)

  8. Effectiveness of chest radiography, lung ultrasound and thoracic computed tomography in the diagnosis of congestive heart failure

    Cardinale, Luciano; Priola, Adriano Massimiliano; Moretti, Federica; Volpicelli, Giovanni

    2014-01-01

    Hydrostatic pulmonary edema is as an abnormal increase in extravascular water secondary to elevated pressure in the pulmonary circulation, due to congestive heart failure or intravascular volume overload. Diagnosis of hydrostatic pulmonary edema is usually based on clinical signs associated to conventional radiography findings. Interpretation of radiologic signs of cardiogenic pulmonary edema are often questionable and subject. For a bedside prompt evaluation, lung ultrasound (LUS) may assess...

  9. The physics analysis and experiment study of zinc sulphide scintillator for fast neutron radiography

    Fast neutron radiography is a promising application for accelerator based neutron sources. The potential effectiveness of this technique depends on the development of suitable imaging detectors for fast neutrons. Zinc sulphide based scintillators have the largest light output per event in the family of imaging scintillators used so far in fast neutron radiography. This paper investigated different aspects of this scintillator in order to determine the factors which might affect the light output. A mathematical model was established to estimate effectiveness of this scintillator. Zinc sulphide screens were prepared with ZnS particles of different concentrations in polypropylene matrix. A 14 MeV fast neutron source was used in the experiments. The light output was detected using a CCD camera or a film coupled to the scintillator screen. The results showed that the optimum scintillators is around 3 mm in thickness with the weight ratio of 2:1 for ZnS and polypropylene

  10. An advanced neutron radiography system

    The Stationary Neutron Radiography System (SNRS) nuclear reactor and radiography systems and their performance are described. The primary mission of the SNRS is to conduct neutron radiographic inspections of aircraft components to detect corrosion and moisture. Preliminary measurements indicate that the facility is capable of producing high quality real-time and film radiography. The reactor is capable of providing various additional services including sample irradiations, nuclear harness testing, in-core irradiations, in-core pneumatic rabbit system irradiations, neutron activation analysis, and pulse and square wave operation. 2 refs

  11. Multidimensional operando analysis of macroscopic structure evolution in lithium sulfur cells by X-ray radiography.

    Risse, S; Jafta, C J; Yang, Y; Kardjilov, N; Hilger, A; Manke, I; Ballauff, M

    2016-04-21

    Lithium sulfur cells are the most promising candidate for the post lithium-ion battery era. Their major drawback is rapid capacity fading attributed to the complex electrochemical processes during charge and discharge which are not known precisely. Here we present for the first time a multidimensional operando measurement by combining X-ray radiography with impedance spectroscopy while galvanostatically charging and discharging a lithium sulfur cell. The formation of macroscopic sulfur crystals at the end of charge can be seen directly by X-ray radiography. These crystals can be assigned to stable α-sulfur (rhombic) and metastable β-sulfur (monoclinic) by their characteristic crystal habit. These crystal structures with a length of more than 1 mm form and dissolve rapidly during cycling. Their appearance is accompanied by characteristic signals in impedance spectroscopy. Macroscopic crystals of Li2S cannot be observed in full agreement with earlier studies by operando X-ray diffraction. In addition, X-ray radiography reveals non-wetted areas on the carbon cathode. These regions grow during discharge and are reduced during charge. The area of these electrochemically inactive spots is inversely proportional to discharge capacity. PMID:27035926

  12. Both pelvic radiography and lateral abdominal radiography correlate well with coronary artery calcification measured by computed tomography in hemodialysis patients: A cross-sectional study.

    Hong, Daqing; Ruan, Yizhe; Pu, Lei; Zhong, Xiang; Zhang, Yuan; Zhang, Yue; Deng, Fei; Yang, Hongling; Li, Guisen; Wang, Li

    2016-07-01

    Introduction Lateral abdominal radiograph is suggested as an alternative to coronary artery computed tomography (CT) in evaluating vascular calcification. Simple scoring systems including pelvic radiograph scoring and abdominal scoring system were utilized to study their correlation with coronary artery calcification. Methods In 106 MHD patients, coronary artery CT, lateral abdominal, and pelvic radiograph were taken. The Agatston scoring system was applied to evaluate the degree of coronary artery calcification which was categorized according to Agatston coronary artery calcification score (CACS) ≥ 30, ≥100, ≥400, and ≥1000. Abdominal aortic calcification was scored by 4-scored and 24-scored systems. Pelvic artery calcification was scored by a 4-scored system. Sensitivities and specificities of abdominal aortic calcification scores and pelvic artery calcification scores to predict different categories of coronary artery calcification were analyzed. We studied the diagnostic capability of abdominal aorta calcification and pelvic artery calcification to predict different CACS categories by calculating likelihood ratios. Receiver operator characteristic curves were used to determine the area under the curve for each of these testing procedures. Findings The prevalence was 48(45.3%), 15 (14.2%), 11 (10.4%), 11 (10.4%), and 11 (10.4%) for CACs > 0, ≥30, ≥100, ≥400, and ≥1000, respectively. The degree of CACs was positively correlated with patient age, prevalence of diabetes, abdominal aorta scores, and pelvic calcification scores. The areas under the curves for different CACS by all X-ray scoring systems were above 0.70 except pelvic 4-scored system for diagnosing CACS ≥30, without significant difference (P > 0.05). Discussion Both lateral abdominal and pelvic plain radiographs were demonstrated as acceptable alternatives to CT in evaluating vascular calcification. PMID:26932162

  13. Neutron induced electron radiography

    In the present paper a new radiography technique, the 'Neutron Induced Electron Radiography' - NIER, to inspect low thickness samples on the order of micra, has been developed. This technique makes use of low energy electrons as penetrating radiation generated from metallic gadolinium screens when irradiated by thermal neutrons. The conditions to obtain the best image for the conventional X-ray film Kodak-AA were determined by using a digital system to quantify the darkening level of the film. The irradiations have been performed at a radiography equipment installed at the beam-hole no. 8 of the 5 MW IEA-R1 nuclear research reactor of IPEN-CNEN/SP. The irradiation time to obtain the best radiography was 100 seconds and for such condition the technique was able to discern 1 μm in 24 μm of aluminum at a resolution of 32 μm. By visual comparison the images obtained by the NIER shown a higher quality when compared with the ones from other usual techniques the make use of electrons a penetrating radiation and films for image registration. Furthermore the use of the digital system has provided a smaller time for data acquisition and data analysis as well as an improvement in the image visualization. (author)

  14. Computed tomography scout views vs. conventional radiography in body-packers – Delineation of body-packs and radiation dose in a porcine model

    Ziegeler, Edvard, E-mail: edvard.ziegeler@campus.lmu.de [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Nussbaumstraße 20, 80336 Munich (Germany); Grimm, Jochen M., E-mail: jochen.grimm@med.lmu.de [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Nussbaumstraße 20, 80336 Munich (Germany); Wirth, Stefan, E-mail: tefan.wirth@med.lmu.de [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Nussbaumstraße 20, 80336 Munich (Germany); Uhl, Michael, E-mail: michael.uhl@polizei.bayern.de [Bavarian State Criminal Police Office, Maillingerstrasse 15, 80636 Munich (Germany); Reiser, Maximilian F., E-mail: Maximilian.Reiser@med.lmu.de [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Nussbaumstraße 20, 80336 Munich (Germany); Scherr, Michael K., E-mail: Michael.Scherr@med.lmu.de [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Nussbaumstraße 20, 80336 Munich (Germany)

    2012-12-15

    Objective: To compare abdominal computed tomography (CT) scout views with conventional radiography regarding radiation dose and delineation of drug packages in a porcine body-packer model. Materials and methods: Nine samples of illicit drugs packed in ovoid plastic containers were consecutively placed in the rectum of a 121.5 kg pig cadaver. Antero-posterior and lateral scout views were obtained at 120 kVp and 80 mA, 150 mA and 200 mA, respectively, using a 64-row MDCT. Scout views were compared with conventional abdominal antero-posterior radiographs (77 kV and 106 ± 13 mAs). Visibility of three body pack characteristics (wrapping, content, shape) was rated independently by two radiologists and summarized to a delineation score ranging from 0 to 9 with a score ≥6 representing sufficient delineation. Mean delineation scores were calculated for each conventional radiography and single plane scout view separately and for a combined rating of antero-posterior and lateral scout views. Results: Even the lowest single plane scout view delineation score (5.3 ± 2.0 for 80 mA lateral; 0.4 mSv; sensitivity = 44%) was significantly higher than for conventional radiographs (3.1 ± 2.5, p < 0.001; 2.4 ± 0.3 mSv; sensitivity = 11%). Combined reading of antero-posterior and lateral scout views 80 mA yielded sufficient delineation (6.2 ± 1.4; 0.8 mSv; sensitivity = 56%). Conclusions: All CT scout views showed significantly better delineation ratings and sensitivity than conventional radiographs. Scout views in two planes at 80 mA provided a sufficient level of delineation and a sensitivity five times higher than conventional radiography at less than one third of the radiation dose. In case of diagnostic insecurity, CT can be performed without additional logistical effort.

  15. Rhinoceros feet step out of a rule-of-thumb: a wildlife imaging pioneering approach of synchronized computed tomography-digital radiography.

    Galateanu, Gabriela; Hermes, Robert; Saragusty, Joseph; Göritz, Frank; Potier, Romain; Mulot, Baptiste; Maillot, Alexis; Etienne, Pascal; Bernardino, Rui; Fernandes, Teresa; Mews, Jurgen; Hildebrandt, Thomas Bernd

    2014-01-01

    Currently, radiography is the only imaging technique used to diagnose bone pathology in wild animals situated under "field conditions". Nevertheless, while chronic foot disease in captive mega-herbivores is widely reported, foot radiographic imaging is confronted with scarcity of studies. Numerous hindrances lead to such limited numbers and it became very clear that the traditional perspective on bone imaging in domestic animals based on extensive studies and elaborated statistical evaluations cannot be extrapolated to their non-domestic relatives. For these reasons, the authors initiated a multi-modality imaging study and established a pioneering approach of synchronized computed tomography (CT) and digital radiography (DR), based on X-ray projections derived from three-dimensional CT reconstructed images. Whereas this approach can be applied in any clinical field, as a case of outstanding importance and great concern for zoological institutions, we selected foot bone pathologies in captive rhinoceroses to demonstrate the manifold applications of the method. Several advances were achieved, endowing the wildlife clinician with all-important tools: prototype DR exposure protocols and a modus operandi for foot positioning, advancing both traditional projections and, for the first-time, species-related radiographic views; assessment of radiographic diagnostic value for the whole foot and, in premiere, for each autopodial bone; together with additional insights into radiographic appearance of bone anatomy and pathology with a unique, simultaneous CT-DR correlation. Based on its main advantages in availing a wide range of keystone data in wildlife imaging from a limited number of examined subjects and combining advantages of CT as the golden standard method for bone diseases' diagnostic with DR's clinical feasibility under field conditions, synchronized CT-DR presents a new perspective on wildlife's health management. With this we hope to provide veterinary clinicians

  16. Contribution of computed tomography in patients with lung metastases of differentiated thyroid carcinoma not apparent on plain radiography who were treated with radioiodine

    Computed tomography (CT or CAT Scan) of the chest is more sensitive than radiography in the detection of lung metastases of differentiated thyroid cancer (DTC), but little information is available regarding the aggregated value of this method. The present study evaluated the response of patients with lung metastases of DTC not apparent on radiography to treatment with 131I and the value of CT in these cases. Twenty-five patients with lung metastases not apparent on radiography, who initially received 100-200 mCi I151, were evaluated and those presenting pulmonary uptake on post-therapy WBS were submitted to a new treatment after 6 to 12 months, and so on. The chance of detection of pulmonary uptake on post-therapy WBS did not differ between patients with negative and positive CT (100% versus 91.5%). Mean serum Tg levels were higher in patients with positive CT (108 ng/ml versus 52 ng/ml). Negative post-therapy WBS was achieved in 82% of patients with positive CT and in 92.3% with negative CT and the cumulative I131 activity necessary to achieve this outcome did not differ between the two groups (mean = 300 mCi). Stimulated Tg was undetectable in 47% of patients with negative CT at the end of treatment, but in none of the patients whose CT continued to be positive. In patients with elevated Tg, the CT result apparently did not change the indication of therapy or the I131 activity to be administered. In cases with lung metastases, the persistence of micronodules on CT was associated with the persistence of detectable Tg in patients presenting negative post-therapy WBS. (author)

  17. Computed tomography scout views vs. conventional radiography in body-packers – Delineation of body-packs and radiation dose in a porcine model

    Objective: To compare abdominal computed tomography (CT) scout views with conventional radiography regarding radiation dose and delineation of drug packages in a porcine body-packer model. Materials and methods: Nine samples of illicit drugs packed in ovoid plastic containers were consecutively placed in the rectum of a 121.5 kg pig cadaver. Antero-posterior and lateral scout views were obtained at 120 kVp and 80 mA, 150 mA and 200 mA, respectively, using a 64-row MDCT. Scout views were compared with conventional abdominal antero-posterior radiographs (77 kV and 106 ± 13 mAs). Visibility of three body pack characteristics (wrapping, content, shape) was rated independently by two radiologists and summarized to a delineation score ranging from 0 to 9 with a score ≥6 representing sufficient delineation. Mean delineation scores were calculated for each conventional radiography and single plane scout view separately and for a combined rating of antero-posterior and lateral scout views. Results: Even the lowest single plane scout view delineation score (5.3 ± 2.0 for 80 mA lateral; 0.4 mSv; sensitivity = 44%) was significantly higher than for conventional radiographs (3.1 ± 2.5, p < 0.001; 2.4 ± 0.3 mSv; sensitivity = 11%). Combined reading of antero-posterior and lateral scout views 80 mA yielded sufficient delineation (6.2 ± 1.4; 0.8 mSv; sensitivity = 56%). Conclusions: All CT scout views showed significantly better delineation ratings and sensitivity than conventional radiographs. Scout views in two planes at 80 mA provided a sufficient level of delineation and a sensitivity five times higher than conventional radiography at less than one third of the radiation dose. In case of diagnostic insecurity, CT can be performed without additional logistical effort.

  18. Cross-sectional void fraction distribution measurements in a vertical annulus two-phase flow by high speed X-ray computed tomography and real-time neutron radiography techniques

    Harvel, G.D. [McMaster Univ., Ontario (Canada)]|[Combustion and Heat Transfer Lab., Takasago (Japan); Hori, K.; Kawanishi, K. [Combustion and Heat Transfer Lab., Takasago (Japan)] [and others

    1995-09-01

    A Real-Time Neutron Radiography (RTNR) system and a high speed X-ray Computed tomography (X-CT) system are compared for measurement of two-phase flow. Each system is used to determine the flow regime, and the void fraction distribution in a vertical annulus flow channel. A standard optical video system is also used to observe the flow regime. The annulus flow channel is operated as a bubble column and measurements obtained for gas flow rates from 0.0 to 30.01/min. The flow regimes observed by all three measurement systems through image analysis shows that the two-dimensional void fraction distribution can be obtained. The X-CT system is shown to have a superior temporal resolution capable of resolving the void fraction distribution in an (r,{theta}) plane in 33.0 ms. Void fraction distribution for bubbly flow and slug flow is determined.

  19. Cholesteatoma: computed tomography and radiography in a dog; Colesteatoma: tomografia computadorizada e radiografia em cao com otite cronica

    Belotta, Alexandra Frey; Babicsak, Viviam Rocco; Mamprim, Maria Jaqueline; Vulcano, Luiz Carlos, E-mail: a_fbelotta@yahoo.com.br [Universidade Estadual Paulista Julio de Mesquita Filho (FMVZ/UNESP), Botucatu, SP (Brazil). Faculdade de Medicina Veterinaria e Zootecnia . Dept. de Reproducao Animal e Radiologia Veterinaria; Arruda, Vanesa Kutz de; Amorim, Rogerio Martins [Universidade Estadual Paulista Julio de Mesquita Filho (FMVZ/UNESP), Botucatu, SP (Brazil). Faculdade de Medicina Veterinaria e Zootecnia. Dept. de Clinica Veterinaria

    2012-07-01

    Cholesteatoma, a rare and/or misdiagnosed disease, results of a serious complication in dogs with chronic otitis. This article describes a case of a dachshund sent to the veterinary hospital presenting signs of cognitive dysfunction associated to peripheral neuropathy of the facial nerve on the right side. At radiography, an enlargement and thickness of the contours associated with loss of anatomical definition of the right tympanic bulla compared to the left was seen. At tomography, this enlargement and thickness were seen with better definition, besides the fulfilling by hyperdense calcified content, bullae osteolysis and temporal bone sclerosis at the same side. (author)

  20. Digital and analogue industrial radiography, application fields

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

  1. Analysis of computer programming languages

    This research thesis aims at trying to identify some methods of syntax analysis which can be used for computer programming languages while putting aside computer devices which influence the choice of the programming language and methods of analysis and compilation. In a first part, the author proposes attempts of formalization of Chomsky grammar languages. In a second part, he studies analytical grammars, and then studies a compiler or analytic grammar for the Fortran language

  2. Digital radiography

    This publication contains the full texts of nearly all the papers read at the meeting (including illustrations and citations) as well as the summaries of discussions about the individual topics. The subjects of main interest during the congress were the fundamentals and uses of digital radiography (13 contributions); transmission and retrieval systems for digital image data (7 contributions); evaluation and promotion of digital image information (3 contributions); lessening of risks from examinations using contrast media (6 contributions); and work-in-progress reports by manufacturers (8 contributions) and users (4 contributions). (orig.)

  3. Digital radiography

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

  4. Analysis of the reproducibility of the gray values and noise of a direct digital radiography system

    Poleti, Marcelo Lupion; FERNANDES, Thais Maria Freire; TEIXEIRA, Renata Cordeiro; Capelozza, Ana Lúcia Alvares; Rubira-Bullen, Izabel Regina Fischer

    2015-01-01

    The aim of this study was to evaluate the reproducibility of the gray values and noise of a direct digital radiography system (Visualix eHD) for various exposure times and analyzed regions. To obtain radiographic images in a standardized manner, the digital sensor of the system and a stepwedge were positioned in a phantom at a focus-film distance of 30 cm in a dental device at 70 kV, 7 mA and 2.2 mm filtration. Ten consecutive repetitions of X-ray imaging were performed at each exposure time ...

  5. Radiography with Polarised Neutrons

    Schulz, Michael

    2010-01-01

    The combination of neutron radiography with one dimensional polarisation analysis developed in this thesis allows the spatially resolved determination of the magnetic properties of weakly ferromagnetic substances. This method can yield valuable information on the nature of the underlying phase transition. The requirements for all components of the experimental setup and their influence on the maximum spatial resolution are discussed extensively in this work. Radiographic as well as tomographi...

  6. Analysis of computer networks

    Gebali, Fayez

    2015-01-01

    This textbook presents the mathematical theory and techniques necessary for analyzing and modeling high-performance global networks, such as the Internet. The three main building blocks of high-performance networks are links, switching equipment connecting the links together, and software employed at the end nodes and intermediate switches. This book provides the basic techniques for modeling and analyzing these last two components. Topics covered include, but are not limited to: Markov chains and queuing analysis, traffic modeling, interconnection networks and switch architectures and buffering strategies.   ·         Provides techniques for modeling and analysis of network software and switching equipment; ·         Discusses design options used to build efficient switching equipment; ·         Includes many worked examples of the application of discrete-time Markov chains to communication systems; ·         Covers the mathematical theory and techniques necessary for ana...

  7. Suresh K. AggarwalQuantified Analysis of a Production Diesel Injector Using X-Ray Radiography and Engine Diagnostics

    Ramirez, Anita I.

    The work presented in this thesis pursues further the understanding of fuel spray, combustion, performance, and emissions in an internal combustion engine. Various experimental techniques including x-ray radiography, injection rate measurement, and in-cylinder endoscopy are employed in this work to characterize the effects of various upstream conditions such as injection rate profile and fuel physical properties. A single non-evaporating spray from a 6-hole full-production Hydraulically Actuated Electronically Controlled Unit Injector (HEUI) nozzle is studied under engine-like ambient densities with x-ray radiography at the Advanced Photon Source (APS) of Argonne National Laboratory (ANL). Two different injection pressures were investigated and parameters such as fuel mass distribution, spray penetration, cone angle, and spray velocity were obtained. The data acquired with x-ray radiography is used for the development and validation of improved Computational Fluid Dynamic (CFD) models. Rate of injection is studied using the same HEUI in a single cylinder Caterpillar test engine. The injection rate profile is altered to have three levels of initial injection pressure rise. Combustion behavior, engine performance, and emissions information was acquired for three rate profile variations. It is found that NOx emission reduction is achieved when the SOI timing is constant at the penalty of lower power generated in the cycle. However, if CA50 is aligned amongst the three profiles, the NOx emissions and power are constant with a slight penalty in CO emissions. The influence of physical and chemical parameters of fuel is examined in a study of the heavy alcohol, phytol (C20H40O), in internal combustion engine application. Phytol is blended with diesel in 5%, 10%, and 20% by volume. Combustion behavior is similar between pure diesel and the phytol/diesel blends with small differences noted in peak cylinder pressure, ignition delay, and heat release rate in the premix burn

  8. Affective Computing and Sentiment Analysis

    Ahmad, Khurshid

    2011-01-01

    This volume maps the watershed areas between two 'holy grails' of computer science: the identification and interpretation of affect -- including sentiment and mood. The expression of sentiment and mood involves the use of metaphors, especially in emotive situations. Affect computing is rooted in hermeneutics, philosophy, political science and sociology, and is now a key area of research in computer science. The 24/7 news sites and blogs facilitate the expression and shaping of opinion locally and globally. Sentiment analysis, based on text and data mining, is being used in the looking at news

  9. LANL12-RS-107J PYTHON Radiography Analysis Tool (PyRAT). Mid-Year Deliverable Report for FY15

    Temple, Brian Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Armstrong, Jerawan Chudoung [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-04-14

    This document is a mid-year report on a deliverable for the PYTHON Radiography Analysis Tool (PyRAT) for project LANL12-RS-107J in FY15. The deliverable is deliverable number 2 in the work package and is titled “Add the ability to read in more types of image file formats in PyRAT”. Right now PyRAT can only read in uncompressed TIF files (tiff files). It is planned to expand the file formats that can be read by PyRAT, making it easier to use in more situations. A summary of the file formats added include jpeg, jpg, png and formatted ASCII files.

  10. Scattering influences in quantitative fission neutron radiography for the in situ analysis of hydrogen distribution in metal hydrides

    In situ neutron radiography allows for the time-resolved study of hydrogen distribution in metal hydrides. However, for a precise quantitative investigation of a time-dependent hydrogen content within a host material, an exact knowledge of the corresponding attenuation coefficient is necessary. Additionally, the effect of scattering has to be considered as it is known to violate Beer's law, which is used to determine the amount of hydrogen from a measured intensity distribution. Within this study, we used a metal hydride inside two different hydrogen storage tanks as host systems, consisting of steel and aluminum. The neutron beam attenuation by hydrogen was investigated in these two different setups during the hydrogen absorption process. A linear correlation to the amount of absorbed hydrogen was found, allowing for a readily quantitative investigation. Further, an analysis of scattering contributions on the measured intensity distributions was performed and is described in detail

  11. Scattering influences in quantitative fission neutron radiography for the in situ analysis of hydrogen distribution in metal hydrides

    Börries, S.; Metz, O.; Pranzas, P. K.; Bücherl, T.; Söllradl, S.; Dornheim, M.; Klassen, T.; Schreyer, A.

    2015-10-01

    In situ neutron radiography allows for the time-resolved study of hydrogen distribution in metal hydrides. However, for a precise quantitative investigation of a time-dependent hydrogen content within a host material, an exact knowledge of the corresponding attenuation coefficient is necessary. Additionally, the effect of scattering has to be considered as it is known to violate Beer's law, which is used to determine the amount of hydrogen from a measured intensity distribution. Within this study, we used a metal hydride inside two different hydrogen storage tanks as host systems, consisting of steel and aluminum. The neutron beam attenuation by hydrogen was investigated in these two different setups during the hydrogen absorption process. A linear correlation to the amount of absorbed hydrogen was found, allowing for a readily quantitative investigation. Further, an analysis of scattering contributions on the measured intensity distributions was performed and is described in detail.

  12. Measurement of water distribution by using neutron radiography and network analysis of gas-velocity distributions in a PEFC

    Fuel gas (hydrogen gas) and oxidant gas (air) are supplied to a Polymer Electrolyte Fuel Cell (PEFC). Condensation may occur in the cathode side, since air is super-saturated by the fuel cell reactions. If condensed water exists in a gas diffusion layer (GDL) or the gas channels, it may affect the fuel cell performances because of blocking the oxygen from reaching the cathode reaction site. In order to clarify water effects on performances of a PEFC, visualization and quantitative measurements of water distributions in a PEFC were carried out by means of neutron radiography. A network analysis of gas-velocity distribution was applied for the experimental results. It analyzes the gas-velocity distribution depending on the flow resistance which is the pressure drop. Applying the measured data of water thickness, pressure drop in the gas channel and the GDL can be obtained. (author)

  13. Scattering influences in quantitative fission neutron radiography for the in situ analysis of hydrogen distribution in metal hydrides

    Börries, S., E-mail: stefan.boerries@hzg.de [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Max-Planck-Strasse 1, D-21502 Geesthacht (Germany); Metz, O.; Pranzas, P.K. [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Max-Planck-Strasse 1, D-21502 Geesthacht (Germany); Bücherl, T. [ZTWB Radiochemie München (RCM), Technische Universität München (TUM), Walther-Meissner-Str. 3, D-85748 Garching (Germany); Söllradl, S. [Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRMII), Technische Universität München (TUM), Lichtenbergstr. 1, D-85748 Garching (Germany); Dornheim, M.; Klassen, T.; Schreyer, A. [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Max-Planck-Strasse 1, D-21502 Geesthacht (Germany)

    2015-10-11

    In situ neutron radiography allows for the time-resolved study of hydrogen distribution in metal hydrides. However, for a precise quantitative investigation of a time-dependent hydrogen content within a host material, an exact knowledge of the corresponding attenuation coefficient is necessary. Additionally, the effect of scattering has to be considered as it is known to violate Beer's law, which is used to determine the amount of hydrogen from a measured intensity distribution. Within this study, we used a metal hydride inside two different hydrogen storage tanks as host systems, consisting of steel and aluminum. The neutron beam attenuation by hydrogen was investigated in these two different setups during the hydrogen absorption process. A linear correlation to the amount of absorbed hydrogen was found, allowing for a readily quantitative investigation. Further, an analysis of scattering contributions on the measured intensity distributions was performed and is described in detail.

  14. LANL12-RS-107J PYTHON Radiography Analysis Tool (PyRAT). Mid-Year Deliverable Report for FY15

    This document is a mid-year report on a deliverable for the PYTHON Radiography Analysis Tool (PyRAT) for project LANL12-RS-107J in FY15. The deliverable is deliverable number 2 in the work package and is titled ''Add the ability to read in more types of image file formats in PyRAT''. Right now PyRAT can only read in uncompressed TIF files (tiff files). It is planned to expand the file formats that can be read by PyRAT, making it easier to use in more situations. A summary of the file formats added include jpeg, jpg, png and formatted ASCII files.

  15. Accuracy of Lung Ultrasonography versus Chest Radiography for the Diagnosis of Adult Community-Acquired Pneumonia: Review of the Literature and Meta-Analysis.

    Xiong Ye

    Full Text Available Lung ultrasonography (LUS is being increasingly utilized in emergency and critical settings. We performed a systematic review of the current literature to compare the accuracy of LUS and chest radiography (CR for the diagnosis of adult community-acquired pneumonia (CAP. We searched in Pub Med, EMBASE dealing with both LUS and CR for diagnosis of adult CAP, and conducted a meta-analysis to evaluate the diagnostic accuracy of LUS in comparison with CR. The diagnostic standard that the index test compared was the hospital discharge diagnosis or the result of chest computed tomography scan as a "gold standard". We calculated pooled sensitivity and specificity using the Mantel-Haenszel method and pooled diagnostic odds ratio using the DerSimonian-Laird method. Five articles met our inclusion criteria and were included in the final analysis. Using hospital discharge diagnosis as reference, LUS had a pooled sensitivity of 0.95 (0.93-0.97 and a specificity of 0.90 (0.86 to 0.94, CR had a pooled sensitivity of 0.77 (0.73 to 0.80 and a specificity of 0.91 (0.87 to 0.94. LUS and CR compared with computed tomography scan in 138 patients in total, the Z statistic of the two summary receiver operating characteristic was 3.093 (P = 0.002, the areas under the curve for LUS and CR were 0.901 and 0.590, respectively. Our study indicates that LUS can help to diagnosis adult CAP by clinicians and the accuracy was better compared with CR using chest computed tomography scan as the gold standard.

  16. Proton radiography in plasma

    Volpe, L., E-mail: luca.volpe@mib.infn.it [Universita degli Studi di Milano-Bicocca, Piazza della scienza 3, Milano 20126 (Italy); Batani, D.; Morace, A. [Universita degli Studi di Milano-Bicocca, Piazza della scienza 3, Milano 20126 (Italy); Nicolai, Ph.; Regan, C. [CELIA, Universite de Bordeaux, CNRS, CEA, F33405 (France); Ravasio, A. [LULI, UMR 7605, CNRS, CEA, Universite Paris VI, Ecole Polytechnique, 91128 Palaiseau Cedex (France)

    2011-10-11

    Generation of high intensity and well collimated multi-energetic proton beams from laser-matter interaction extends the possibility to use protons as a diagnostic tool to image imploding target in Inertial Confinement Fusion (ICF) experiments. Due to the very large mass densities reached during implosion, protons traveling through the target undergo a very large number of collisions. Therefore the analysis of experimentally obtained proton images requires care and accurate numerical simulations using both hydrodynamic and Monte Carlo codes. The impact of multiple scattering needs to be carefully considered by taking into account the exact stopping power for dense matter and for the underdense plasma corona. In our paper, density, temperature and ionization degree profiles of the imploding target are obtained by 2D hydrodynamic simulations performed using CHIC code. Proton radiography images are simulated using the Monte Carlo code (MCNPX; adapted to correctly describe multiple scattering and plasma stopping power) in order to reconstruct the complete hydrodynamic history of the imploding target. Finally we develop a simple analytical model to study the performance of proton radiography as a function of initial experimental parameters, and identify two different regimes for proton radiography in ICF.

  17. Orthopaedic measurements with computed radiography: Methodological development, accuracy, and radiation dose with special reference to the weight-bearing lower extremity and the dislocating patella

    The overall aim of this study was to develop and evaluate a measurement system for computed radiography and Picture Archiving and Communication Systems, permitting measurements of long distances and angles in and between related images. The developed measurement system, which was based on the QUESTOR Precision Radiography system, was applied to the weight-bearing knee with special reference to the dislocating patella. The QPR system modified for CR fulfilled the criteria for measuring the weight-bearing knee. The special measuring assistance tools that were developed were important for the implementation of CR and PACS, particularly in workstations programmed for musculoskeletal radiology. The energy imparted to the patient was reduced by 98% at the lowest exposure of the CR-system, compared with our conventional analogue method, without loss of diagnostic accuracy. The CR technique creates a possibility, to an extent not previously feasible, to differentiate the exposure parameters (and thus minimise the radiation dose to the patient) by carefully considering the purpose of the examination. A radiographic method for measuring the rotation of the femur and the tibia, and the patellar translation was developed and applied to healthy volunteers. The introduced patellar variables have yielded new insights into the complex sequence of motions between the femur, tibia, and patella. The patients with a dislocating patella were subdivided into one 'clean' group of spontaneous dislocations and one group with various traumas in the history, which thus resulted in two groups with distinct radiographic differences. The Q-angle was decreased in knees that had suffered dislocations, and the traditional surgical treatment with a further reduction of the Q-angle must be challenged. The use of clinical measurements of the Q-angle was not an optimal way to evaluate the mechanical alignment in the patellofemoral joint under physiological conditions. In this study, we have proved

  18. Portable digital electronic radiography system

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

  19. Neutron radiography at the HFR Petten

    This report contains the five papers on neutron radiography activities at the Petten High Flux Reactor (HFR) presented at the Third World Conference on Neutron Radiography which was held in May 1989 in Osaka, Japan. In addition, a survey on neutron radiography in Europe for industry and research as presented at the SITEF NDT symposium 1989 on European Advances in Non-Destructive Testing, held in Toulouse/France in October 1989 is included. The papers compiled here are concerned with: the neutron radiography services available in Petten; the experience with and applications of neutron radiography at Petten; image evaluation and analysis techniques at Petten; the practical utilization of nitrocellulose film in neutron radiography in Europe; an introduction into the basic principles of neutron radiography; an overview of the neutron radiography facilities in Europe for industry and research; and a survey of typical applications of neutron radiography in industry, research and sciences. It is the intention of this compilation to provide a comprehensive overview of the present Petten activities and European facilities in this young and promising field of non-destructive testing of materials and components from the nuclear and the non-nuclear industries and research organizations, and from the sciences

  20. Industrial radiographies

    2005-01-01

    The Radiation Protection group wishes to remind CERN staff responsible for contractors performing X-ray inspections on the CERN sites that the firms must apply the legislation in force in their country of origin, in particular with regard to the prevention of risks relating to ionizing radiation. Industrial radiography firms called on to work on the CERN sites must also comply with the rules laid down in CERN's Radiation Safety Manual and be registered in the relevant CERN database. Since CERN is responsible for safety on its own site, a number of additional rules have been laid down for this kind of work, as set out in Radiation Protection Procedure PRP30 https://edms.cern.ch/file/346848/LAST_RELEASED/PRP30.pdf The CERN Staff Member responsible for the contract shall register the company and issue notification that an X-ray inspection is to be performed via the web interface at the following address: http://cern.ch/rp-radio

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

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

  2. Dynamic calibration and analysis of crack tip propagation in energetic materials using real-time radiography

    Butt, Ali

    Crack propagation in a solid rocket motor environment is difficult to measure directly. This experimental and analytical study evaluated the viability of real-time radiography for detecting bore regression and propellant crack propagation speed. The scope included the quantitative interpretation of crack tip velocity from simulated radiographic images of a burning, center-perforated grain and actual real-time radiographs taken on a rapid-prototyped model that dynamically produced the surface movements modeled in the simulation. The simplified motor simulation portrayed a bore crack that propagated radially at a speed that was 10 times the burning rate of the bore. Comparing the experimental image interpretation with the calibrated surface inputs, measurement accuracies were quantified. The average measurements of the bore radius were within 3% of the calibrated values with a maximum error of 7%. The crack tip speed could be characterized with image processing algorithms, but not with the dynamic calibration data. The laboratory data revealed that noise in the transmitted X-Ray intensity makes sensing the crack tip propagation using changes in the centerline transmitted intensity level impractical using the algorithms employed.

  3. Analysis of the reproducibility of the gray values and noise of a direct digital radiography system.

    Poleti, Marcelo Lupion; Fernandes, Thais Maria Freire; Teixeira, Renata Cordeiro; Capelozza, Ana Lúcia Alvares; Rubira-Bullen, Izabel Regina Fischer

    2015-01-01

    The aim of this study was to evaluate the reproducibility of the gray values and noise of a direct digital radiography system (Visualix eHD) for various exposure times and analyzed regions. To obtain radiographic images in a standardized manner, the digital sensor of the system and a stepwedge were positioned in a phantom at a focus-film distance of 30 cm in a dental device at 70 kV, 7 mA and 2.2 mm filtration. Ten consecutive repetitions of X-ray imaging were performed at each exposure time (0.05, 0.07, 0.09 and 0.13 s). Gray values were analyzed using ImageJ software in five regions of interest (ROIs): alveolar bone (AB), soft tissue (ST) and three steps of the stepwedge (S1, S2 and S3). The results showed that both the variability of the gray values and the noise were statistically greater (p < 0.05) in the most radiolucent region (ST). Only the noise was affected by the exposure time. In conclusion, the reproducibility of the gray values and the noise of the Visualix eHD system can vary in specific areas with different radiolucency. PMID:26017488

  4. Analysis of the reproducibility of the gray values and noise of a direct digital radiography system

    Marcelo Lupion POLETI

    2015-01-01

    Full Text Available The aim of this study was to evaluate the reproducibility of the gray values and noise of a direct digital radiography system (Visualix eHD for various exposure times and analyzed regions. To obtain radiographic images in a standardized manner, the digital sensor of the system and a stepwedge were positioned in a phantom at a focus-film distance of 30 cm in a dental device at 70 kV, 7 mA and 2.2 mm filtration. Ten consecutive repetitions of X-ray imaging were performed at each exposure time (0.05, 0.07, 0.09 and 0.13 s. Gray values were analyzed using ImageJ software in five regions of interest (ROIs: alveolar bone (AB, soft tissue (ST and three steps of the stepwedge (S1, S2 and S3. The results showed that both the variability of the gray values and the noise were statistically greater (p < 0.05 in the most radiolucent region (ST. Only the noise was affected by the exposure time. In conclusion, the reproducibility of the gray values and the noise of the Visualix eHD system can vary in specific areas with different radiolucency.

  5. A UK-wide analysis of trait emotional intelligence within the radiography profession

    The aim of this study was to profile the Trait emotional intelligence (EI) of the radiography profession, explore any differences between subgroups, compare the profession with a normative group and investigate the relationship between EI and the leaders of the profession. An online UK-wide survey was conducted using the Trait Emotional Intelligence Questionnaire, a self-report measure. Three main analyses were undertaken to investigate any differences between the sample and population, the radiographer subgroups and the sample and a normative group. The sample had similar characteristics to the population. There were differences between types of radiographer, with nuclear medicine radiographers scoring consistently lower than other groups. There were differences between the leaders and other members of the profession particularly in the Sociability factor. Radiographers scored higher than the TEIQue normative group for Global EI and three of the four factors. The study has benchmarked the Trait EI of one healthcare profession and identified areas for future research to develop our understanding of emotional intelligence.

  6. Computer vision in microstructural analysis

    Srinivasan, Malur N.; Massarweh, W.; Hough, C. L.

    1992-01-01

    The following is a laboratory experiment designed to be performed by advanced-high school and beginning-college students. It is hoped that this experiment will create an interest in and further understanding of materials science. The objective of this experiment is to demonstrate that the microstructure of engineered materials is affected by the processing conditions in manufacture, and that it is possible to characterize the microstructure using image analysis with a computer. The principle of computer vision will first be introduced followed by the description of the system developed at Texas A&M University. This in turn will be followed by the description of the experiment to obtain differences in microstructure and the characterization of the microstructure using computer vision.

  7. Computer aided safety analysis 1989

    The meeting was conducted in a workshop style, to encourage involvement of all participants during the discussions. Forty-five (45) experts from 19 countries, plus 22 experts from the GDR participated in the meeting. A list of participants can be found at the end of this volume. Forty-two (42) papers were presented and discussed during the meeting. Additionally an open discussion was held on the possible directions of the IAEA programme on Computer Aided Safety Analysis. A summary of the conclusions of these discussions is presented in the publication. The remainder of this proceedings volume comprises the transcript of selected technical papers (22) presented in the meeting. It is the intention of the IAEA that the publication of these proceedings will extend the benefits of the discussions held during the meeting to a larger audience throughout the world. The Technical Committee/Workshop on Computer Aided Safety Analysis was organized by the IAEA in cooperation with the National Board for Safety and Radiological Protection (SAAS) of the German Democratic Republic in Berlin. The purpose of the meeting was to provide an opportunity for discussions on experiences in the use of computer codes used for safety analysis of nuclear power plants. In particular it was intended to provide a forum for exchange of information among experts using computer codes for safety analysis under the Technical Cooperation Programme on Safety of WWER Type Reactors (RER/9/004) and other experts throughout the world. A separate abstract was prepared for each of the 22 selected papers. Refs, figs tabs and pictures

  8. International Neutron Radiography Newsletter

    Domanus, Joseph Czeslaw

    1986-01-01

    At the First World Conference on Neutron Radiography i t was decided to continue the "Neutron Radiography Newsletter", published previously by J.P. Barton, as the "International Neutron Radiography Newsletter" (INRNL), with J.C. Doraanus as editor. The British Journal of Non-Destructive Testing...

  9. Research on computed tomography reconstructions from one or two radiographs: A report and the application to FXR radiography

    Back, N.; Schneberk, D.; McMillan, C.; Azevedo, S.; Gorvad, M.

    1995-01-26

    This report documents some cooperative research into volumetric image reconstruction from single radiographs. Imaging dynamic events is the most important application for this type of work, but the techniques have possible extensions. Two general objectives guide this work. The first objective is to gain an understanding of the assumptions and limitations of single-view methods for representing internal features. Second, we endeavor to obtain and/or develop techniques for performing image reconstructions with FXR radiographs. If possible, we seek to obtain some quantitative measure of the accuracy of this class of image reconstructions in two respects: (i) in terms of the dimensional accuracy of feature boundaries, and (ii) as pertains to the accuracy of the voxel intensities. Dynamic events are not always self-calibrating, and it is important to establish the reconstruction accuracy of single-view methods for placing bounds on the kinds of conclusions which can be advanced from single-view reconstructed images. Computed tomographic image reconstructions provide dimensional detail of internal structures of objects and provide a measure of the per-voxel attenuation of material in the object. When assumptions behind a reconstruction algorithm are not satisfied, or are satisfied in a limited way, the accuracy of the reconstructed image is compromised. It is the goal of Cr analysis to discern the {open_quotes}real{close_quotes} features of the internals of an object in the midst of a certain level of artifactual content in the image. By understanding the ways in which CT reconstructions from a single radiograph can produce misleading results we hope to develop some measure of the benefits and limitations of single view techniques. 31 refs., 20 figs.

  10. The academic analysis for the parameter and performance of 6LiF-ZnS neutron radiography scintillator

    Expatiate the luminescence theory of neutron radiography scintillator,the mathematical model is set up. Matlah is adopted to simulate and discuss the parameter and performance of scintillator, got some significative conclusion. (authors)

  11. Computational analysis of cerebral cortex

    Takao, Hidemasa; Abe, Osamu; Ohtomo, Kuni [University of Tokyo, Department of Radiology, Graduate School of Medicine, Tokyo (Japan)

    2010-08-15

    Magnetic resonance imaging (MRI) has been used in many in vivo anatomical studies of the brain. Computational neuroanatomy is an expanding field of research, and a number of automated, unbiased, objective techniques have been developed to characterize structural changes in the brain using structural MRI without the need for time-consuming manual measurements. Voxel-based morphometry is one of the most widely used automated techniques to examine patterns of brain changes. Cortical thickness analysis is also becoming increasingly used as a tool for the study of cortical anatomy. Both techniques can be relatively easily used with freely available software packages. MRI data quality is important in order for the processed data to be accurate. In this review, we describe MRI data acquisition and preprocessing for morphometric analysis of the brain and present a brief summary of voxel-based morphometry and cortical thickness analysis. (orig.)

  12. Computational system for geostatistical analysis

    Vendrusculo Laurimar Gonçalves

    2004-01-01

    Full Text Available Geostatistics identifies the spatial structure of variables representing several phenomena and its use is becoming more intense in agricultural activities. This paper describes a computer program, based on Windows Interfaces (Borland Delphi, which performs spatial analyses of datasets through geostatistic tools: Classical statistical calculations, average, cross- and directional semivariograms, simple kriging estimates and jackknifing calculations. A published dataset of soil Carbon and Nitrogen was used to validate the system. The system was useful for the geostatistical analysis process, for the manipulation of the computational routines in a MS-DOS environment. The Windows development approach allowed the user to model the semivariogram graphically with a major degree of interaction, functionality rarely available in similar programs. Given its characteristic of quick prototypation and simplicity when incorporating correlated routines, the Delphi environment presents the main advantage of permitting the evolution of this system.

  13. Neutron-induced alpha radiography

    A new radiography technique to inspect thin samples was developed. Low energy alpha particles, generated by a boron based screen under thermal neutron irradiation, are used as penetrating radiation. The solid state nuclear track detector CR-39 has been used to register the image. The interaction of the α - particles with the CR-39 gives rise to damages which under an adequate chemical etching became tracks the basic units forming the image. A digital system was developed for data acquisition and data analysis as well as for image processing. The irradiation and etching conditions to obtain the best radiography are 1,3 hours and 25 minutes at 70 deg C respectively. For such conditions samples having 10 μm in thickness can be inspected with a spatial resolution of 32 μm. The use of the digital system has reduced the time spent for data acquisition and data analysis and has improved the radiography image visualization. Furthermore, by using the digital system, it was possible to study several new parameters regarding the tracks which are very important to understand and study the image formation theory in solid state nuclear track detectors, the one used in this thesis. Some radiography images are also shown which demonstrate the potential of the proposed radiography technique. When compared with the other radiography techniques already in use to inspect thin samples, the present one developed in the present paper allows a smaller time to obtain the image, it is not necessary to handle liquid radioactive substances, the detector is insensitive to β, γ, X-ray and visible light. (author)

  14. The application of anatomical side markers during abdominal and IVU examinations: An investigation of practice prior to and post-installation of computed radiography (CR)

    Platt, Jane M. [Norfolk and Norwich University Hospital NHS Trust, Norwich (United Kingdom); Strudwick, Ruth M. [University Campus Suffolk, Waterfront Building, Neptune Quay, Ipswich IP4 1QJ (United Kingdom)], E-mail: r.strudwick@ucs.ac.uk

    2009-11-15

    Professionally, radiographers are accountable for their practice. Available literature highlights the ramifications of not using anatomical side markers within the primary beam. It was thought by the authors that the installation of a computed radiography (CR) system could potentially cause a change in practice due to the ease of adding anatomical side markers manually/electronically during post-processing. This study assessed anatomical marker use within the primary beam at a district general hospital in East Anglia, one-year pre-CR installation and one-year post-CR installation. 100 abdominal images were evaluated from each time period and the presence of anatomical side markers was recorded and compared to establish any significant change. The study showed that although there was a decline in use of anatomical side markers used within the primary beam post-CR installation (from 32% to 25%), the changes were not statistically significant (p > 0.05). However, the agreed standard of 100% images having the primary beam side marker present was not met. There is a conflict of opinion about the necessity for anatomical side markers to be used within the primary beam. However, the researchers believe there is a case for recommending alterations and improvements to practice to comply with 'best practice' requirements.

  15. A simple quality assurance test tool for the visual verification of light and radiation field congruent using electronic portal images device and computed radiography

    The radiation field on most megavoltage radiation therapy units are shown by a light field projected through the collimator by a light source mounted inside the collimator. The light field is traditionally used for patient alignment. Hence it is imperative that the light field is congruent with the radiation field. A simple quality assurance tool has been designed for rapid and simple test of the light field and radiation field using electronic portal images device (EPID) or computed radiography (CR). We tested this QA tool using Varian PortalVision and Elekta iViewGT EPID systems and Kodak CR system. Both the single and double exposure techniques were evaluated, with double exposure technique providing a better visualization of the light-radiation field markers. The light and radiation congruency could be detected within 1 mm. This will satisfy the American Association of Physicists in Medicine task group report number 142 recommendation of 2 mm tolerance. The QA tool can be used with either an EPID or CR to provide a simple and rapid method to verify light and radiation field congruence

  16. Experimental and clinical studies on the usefulness and assessment of the angiographic images processed by a digital radiography system (FCR: Fuji Computed Tomography)

    The purpose of this study was to assess experimentally and clinically the usefulness of Fuji Computed Radiography (FCR) in angiographic examinations. FCR had a spatial resolution with much lower X-ray exposure doses, although the resolution of FCR was generally inferior to conventional films. When a contrast medium of 1% iodine concentration was used, FCR pinpointed a mass 1.5 mm in diameter; and conventional film could detect a mass 2.2 mm in diameter. The contrast of iodine in FCR examinations was stable. A high sensitivity of imaging plate allowed a wide range of visualization. In 148 selective angiographic examinatinons for 138 patients, FCR-subtraction images were superior to conventional film angiography for contrast resolution; it had a high sensitivity in detecting areas, such as the mediastimun and left lobe of the liver, and tumor stains in capillary phase. The capability of FCR arteriogram was as good as film arteriogram even with a half concentration of contrast medium and a half exposure dose of X-ray. Among 86 patients undergoing IVDSA examinations, 69 patients (81%) showed clinically satisfactory outcome of IVDSA by using FCR. In the remaining patients, insufficient outcome of IVDSA was due to inappropriate elimination of patietns' motion and suspension of respiration. These results suggest that FCR has the ability to improve image quality of conventional film angiography, as well as to maintain the proper image even with lower X-ray dose or lower dose of contrast medium and without arterial approach in IVDSA. (Namekawa, K)

  17. A simple quality assurance test tool for the visual verification of light and radiation field congruent using electronic portal images device and computed radiography

    Njeh Christopher F

    2012-03-01

    Full Text Available Abstract Background The radiation field on most megavoltage radiation therapy units are shown by a light field projected through the collimator by a light source mounted inside the collimator. The light field is traditionally used for patient alignment. Hence it is imperative that the light field is congruent with the radiation field. Method A simple quality assurance tool has been designed for rapid and simple test of the light field and radiation field using electronic portal images device (EPID or computed radiography (CR. We tested this QA tool using Varian PortalVision and Elekta iViewGT EPID systems and Kodak CR system. Results Both the single and double exposure techniques were evaluated, with double exposure technique providing a better visualization of the light-radiation field markers. The light and radiation congruency could be detected within 1 mm. This will satisfy the American Association of Physicists in Medicine task group report number 142 recommendation of 2 mm tolerance. Conclusion The QA tool can be used with either an EPID or CR to provide a simple and rapid method to verify light and radiation field congruence.

  18. Forensic Analysis of Compromised Computers

    Wolfe, Thomas

    2004-01-01

    Directory Tree Analysis File Generator is a Practical Extraction and Reporting Language (PERL) script that simplifies and automates the collection of information for forensic analysis of compromised computer systems. During such an analysis, it is sometimes necessary to collect and analyze information about files on a specific directory tree. Directory Tree Analysis File Generator collects information of this type (except information about directories) and writes it to a text file. In particular, the script asks the user for the root of the directory tree to be processed, the name of the output file, and the number of subtree levels to process. The script then processes the directory tree and puts out the aforementioned text file. The format of the text file is designed to enable the submission of the file as input to a spreadsheet program, wherein the forensic analysis is performed. The analysis usually consists of sorting files and examination of such characteristics of files as ownership, time of creation, and time of most recent access, all of which characteristics are among the data included in the text file.

  19. Orthopaedic measurements with computed radiography: Methodological development, accuracy, and radiation dose with special reference to the weight-bearing lower extremity and the dislocating patella

    Sanfridsson, J. [Univ. Hospital, Lund (Sweden). Dept. of Diagnostic Radiology

    2001-03-01

    The overall aim of this study was to develop and evaluate a measurement system for computed radiography and Picture Archiving and Communication Systems, permitting measurements of long distances and angles in and between related images. The developed measurement system, which was based on the QUESTOR Precision Radiography system, was applied to the weight-bearing knee with special reference to the dislocating patella. The QPR system modified for CR fulfilled the criteria for measuring the weight-bearing knee. The special measuring assistance tools that were developed were important for the implementation of CR and PACS, particularly in workstations programmed for musculoskeletal radiology. The energy imparted to the patient was reduced by 98% at the lowest exposure of the CR-system, compared with our conventional analogue method, without loss of diagnostic accuracy. The CR technique creates a possibility, to an extent not previously feasible, to differentiate the exposure parameters (and thus minimise the radiation dose to the patient) by carefully considering the purpose of the examination. A radiographic method for measuring the rotation of the femur and the tibia, and the patellar translation was developed and applied to healthy volunteers. The introduced patellar variables have yielded new insights into the complex sequence of motions between the femur, tibia, and patella. The patients with a dislocating patella were subdivided into one 'clean' group of spontaneous dislocations and one group with various traumas in the history, which thus resulted in two groups with distinct radiographic differences. The Q-angle was decreased in knees that had suffered dislocations, and the traditional surgical treatment with a further reduction of the Q-angle must be challenged. The use of clinical measurements of the Q-angle was not an optimal way to evaluate the mechanical alignment in the patellofemoral joint under physiological conditions. In this study, we have

  20. Image registration in intra-oral radiography

    Leung, CC; Yiu, KL; Zee, KY; Tsui, WK

    2005-01-01

    Image registration is one of the image processing methods which is widely used in computer vision, pattern recognition, and medical imaging. In digital subtraction radiography, image registration is one of the important prerequisites to match the reference and subsequent images. In this paper, we propose an automatic non-rigid registration method namely curvature-based registration that relies on a curvature based penalizing term and its application on dental radiography. The regularizing ter...

  1. Imaging in rheumatoid arthritis--status and recent advances for magnetic resonance imaging, ultrasonography, computed tomography and conventional radiography

    Østergaard, Morten; Dohn, U.M.; Østergaard, Mikkel;

    2008-01-01

    , and have several documented and potential applications in RA patients. This chapter will review key aspects of the current status and recent important advances in imaging in RA, briefly discussing X-ray and computed tomography, and particularly focusing on MRI and US. Suggestions for use in clinical trials...

  2. Outcome of root canal treatment in dogs determined by periapical radiography and cone-beam computed tomography scans

    F.W.G. de Paula-Silva; B. Hassan; L.A.B. da Silva; M.R. Leonardo; M.K. Wu

    2009-01-01

    The purpose of this study was to compare the favorable outcome of root canal treatment determined by periapical radiographs (PRs) and cone beam computed tomography (CBCT) scans. Ninety-six roots of dogs' teeth were used to form four groups (n= 24). In group 1, root canal treatments were performed in

  3. Simulation analysis and exp erimental verification of fast neutron radiography%快中子照相模拟分析与实验验证∗

    鲁昌兵; 许鹏; 鲍杰; 王朝辉; 张凯; 任杰; 刘艳芬

    2015-01-01

    Expression for the formation of the pixel value of fast neutron radiography has been derived. The contrast inequality for the photograph has been established using the derived expression;then the relationships of the image contrast with the source intensity, the exposure time, and the scattering have therefore been obtained through the acquired inequality. A simulation on the process of fast neutron radiography is carried out based on the pixel value analysis, and the spatial resolution and image contrast have also been considered. Simulation results show that the spatial resolution is better than that from experiments and the effect of image contrast is equivalent to that of the experiments. Finally, various samples, such as Pb samples, with slits, Fe samples with square holes and multiple materials-combined samples, are used to test the performance of the simulation. Results demonstrate that the simulations are in agreement with the experiments, thus providing a reference to the future experimental design and engineering application.

  4. Radiography with polarised neutrons

    Schulz, Michael L.

    2010-08-20

    In this thesis I present a new technique for the spatially resolved investigation of the magnetic properties of bulk samples. Standard one dimensional neutron depolarisation analysis is combined with neutron radiography to a method we call Neutron Depolarisation Imaging (NDI). The experimental setup which was installed at the neutron radiography beam line ANTARES at FRM II consists of a double crystal monochromator, neutron polariser, spin flipper, polarisation analyser and a position sensitive CCD detector. A comprehensive discussion of the requirements for these components is given and the limitations of the method are shown. The maximum spatial resolution which can be achieved with a neutron radiography setup is determined by the collimation of the neutron beam and the distance between sample and detector. Different types of polarisers have been tested and their advantages and disadvantages are discussed. A double crystal monochromator and a new type of polariser employing polarising neutron supermirrors based on the principle of an optical periscope were developed and tested during this work. Furthermore, NDI measurements on various samples of the weakly ferromagnetic materials Pd{sub 1-x}Ni{sub x} and Ni{sub 3}Al are presented. Neutron depolarisation radiography and tomography measurements were conducted with a spatial resolution as high as 0.3 mm on Pd{sub 1-x}Ni{sub x} and Ni{sub 3}Al samples. The feasibility of NDI experiments under hydrostatic pressures up to 10 kbar was shown on a sample of Ni{sub 3}Al using a modified Cu:Be clamp cell. A decrease of the ordering temperature by 2 K under hydrostatic pressure was determined from the NDI measurements and shows the potential of the method for further high pressure experiments. Additionally a method was developed which in principle allows to obtain the intrinsic dependence of the ordering temperature T{sub C} on the ordered moment Ms from NDI measurements on inhomogeneous samples containing regions with

  5. Radiography with polarised neutrons

    In this thesis I present a new technique for the spatially resolved investigation of the magnetic properties of bulk samples. Standard one dimensional neutron depolarisation analysis is combined with neutron radiography to a method we call Neutron Depolarisation Imaging (NDI). The experimental setup which was installed at the neutron radiography beam line ANTARES at FRM II consists of a double crystal monochromator, neutron polariser, spin flipper, polarisation analyser and a position sensitive CCD detector. A comprehensive discussion of the requirements for these components is given and the limitations of the method are shown. The maximum spatial resolution which can be achieved with a neutron radiography setup is determined by the collimation of the neutron beam and the distance between sample and detector. Different types of polarisers have been tested and their advantages and disadvantages are discussed. A double crystal monochromator and a new type of polariser employing polarising neutron supermirrors based on the principle of an optical periscope were developed and tested during this work. Furthermore, NDI measurements on various samples of the weakly ferromagnetic materials Pd1-xNix and Ni3Al are presented. Neutron depolarisation radiography and tomography measurements were conducted with a spatial resolution as high as 0.3 mm on Pd1-xNix and Ni3Al samples. The feasibility of NDI experiments under hydrostatic pressures up to 10 kbar was shown on a sample of Ni3Al using a modified Cu:Be clamp cell. A decrease of the ordering temperature by 2 K under hydrostatic pressure was determined from the NDI measurements and shows the potential of the method for further high pressure experiments. Additionally a method was developed which in principle allows to obtain the intrinsic dependence of the ordering temperature TC on the ordered moment Ms from NDI measurements on inhomogeneous samples containing regions with different ordering temperatures. This procedure was

  6. Visualization and quantification of water movement in porous cement-based materials by real time thermal neutron radiography:Theoretical analysis and experimental study

    2010-01-01

    Water movement in porous cement-based materials is of great importance when studying their deterioration processes and durability.Many traditional methods based on mass changes,electricity or nuclear magnetic resonances are available for studying water transport in cement-based materials.In this research,an advanced technique i.e.thermal neutron radiography was utilized to achieve visualization and quantification of time dependent water movement including water penetration and moisture vapor in porous cement-based materials through theoretical analysis and experimental study.Because thermal neutrons ex-perience a strong attenuation by hydrogen,neutron radiography exhibits high sensitivity to small amounts of water.A neutron transmission analysis for quantitative evaluation of raw radiographic measurements was developed and optimized based on point scattered functions(PScF).The determinations of the real time and space dependent water penetration into uncracked and cracked mortar samples,as well as the drying process have been presented in this paper.It is illustrated that thermal neutron radiography can be a useful research tool for visualization and quantification of water movement in porous building materials.The obtained results will help us to better understand deteriorating processes of cement-based materials and to find ways to improve their durability.

  7. Digital radiography: an overview.

    Parks, Edwin T; Williamson, Gail F

    2002-11-15

    Since the discovery of X-rays in 1895, film has been the primary medium for capturing, displaying, and storing radiographic images. It is a technology that dental practitioners are the most familiar and comfortable with in terms of technique and interpretation. Digital radiography is the latest advancement in dental imaging and is slowly being adopted by the dental profession. Digital imaging incorporates computer technology in the capture, display, enhancement, and storage of direct radiographic images. Digital imaging offers some distinct advantages over film, but like any emerging technology, it presents new and different challenges for the practitioner to overcome. This article presents an overview of digital imaging including basic terminology and comparisons with film-based imaging. The principles of direct and indirect digital imaging modalities, intraoral and extraoral applications, image processing, and diagnostic efficacy will be discussed. In addition, the article will provide a list of questions dentists should consider prior to purchasing digital imaging systems for their practice. PMID:12444400

  8. Computability and Analysis, a Historical Approach

    Brattka, Vasco

    2016-01-01

    The history of computability theory and and the history of analysis are surprisingly intertwined since the beginning of the twentieth century. For one, \\'Emil Borel discussed his ideas on computable real number functions in his introduction to measure theory. On the other hand, Alan Turing had computable real numbers in mind when he introduced his now famous machine model. Here we want to focus on a particular aspect of computability and analysis, namely on computability properties of theorem...

  9. A Petaflops Era Computing Analysis

    Preston, Frank S.

    1998-01-01

    This report covers a study of the potential for petaflops (1O(exp 15) floating point operations per second) computing. This study was performed within the year 1996 and should be considered as the first step in an on-going effort. 'Me analysis concludes that a petaflop system is technically feasible but not feasible with today's state-of-the-art. Since the computer arena is now a commodity business, most experts expect that a petaflops system will evolve from current technology in an evolutionary fashion. To meet the price expectations of users waiting for petaflop performance, great improvements in lowering component costs will be required. Lower power consumption is also a must. The present rate of progress in improved performance places the date of introduction of petaflop systems at about 2010. Several years before that date, it is projected that the resolution limit of chips will reach the now known resolution limit. Aside from the economic problems and constraints, software is identified as the major problem. The tone of this initial study is more pessimistic than most of the Super-published material available on petaflop systems. Workers in the field are expected to generate more data which could serve to provide a basis for a more informed projection. This report includes an annotated bibliography.

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

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

  11. Digital radiography and advanced imaging techniques in dentistry

    Burcu Keles Evlice; Haluk Oztunc

    2013-01-01

    Since the discovery of x-rays in 1895, film has been the primary medium for capturing, displaying and storing radiographic images. Digital or filmless radiography is slowly being adopted by the dental profession. Digital radiography offers a number of capabilities compared with conventional radiography, such as postprocessing, electronic archiving, concurrent access to images, and improved data distribution. Computer based applications which are used for quantitative measurements and evaluati...

  12. Magnification radiography in osteomyelitis

    Osteomyelitis often eludes early diagnosis because plain film radiography is too insensitive and radionuclide bone scanning is nonspecific. In this study, 90 diabetic patients were studied with plain film and magnification radiographs of their feet. Among the 24 patients with osteomyelitis, plain radiographs suggested the diagnosis in 14 patients and magnification radiography was diagnostic in 18 of these patients. Thus, magnification radiography offers some diagnostic advantage in patients suspected of having osteomyelitis. (orig.)

  13. Experimental study of the X-ray spectra optimization for computed radiography mammography systems; Investigacao experimental da otimizacao do espectro de raios X em sistemas de mamografia computadorizada

    Tomal, Alessandra, E-mail: atomal@ifi.unicamp.br [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Instituto de Fisica Gleb Wataghin; Cunha, Diego M. [Universidade Federal de Uberlandia (UFU), Uberlandia, MG (Brazil). Instituto de Fisica; Nogueira, Maria S. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Gaspar, Fabio [Vigilancia Sanitaria, Campinas, SP (Brazil); Poletti, Martin E. [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Departamento de Fisica

    2013-12-15

    Digital mammography is replacing screen-film mammography due to several advantages of digital receptors. The use of Computed Radiography (CR) mammography systems has been considered an alternative to achieve digital images with a low cost. Besides, the optimization of the X-ray spectrum, characterized by the anode/filter combination and tube potential, is an important step in order to improve the image quality with the lower dose to the breast. In this work, we investigated the optimal X-ray spectra using a figure of merit for two mammography equipment: Senographe DMR (General Electric Medical Systems) and Mammomat 3000 Nova (Siemens), both using an image plate Kodak EHR-M2 (Kodak DirectView). A PMMA phantom, simulating breast with thicknesses of 5 cm, was used. The anode/filter combinations evaluated were: Mo/Mo, Mo/Rh, Rh/Rh and Rh/Al for the Senographe system, and Mo/Mo, Mo/Rh, W/Rh for the Mammomat system, for all the intervals of tube potential range from 24 to 35 kVp. Results demonstrate that the higher values of FOM were achieved with the Rh/Rh at 29 kVp and Rh/Al at 26 kVp for the Senographe system, and for the W/Rh at 28 kVp in the Mammomat one. The reduction in the dose associated with the optimum spectra was 13 and 26% for the Senographe and Mammomat systems, respectively. Finally, our results suggest that anode/filter combinations of more energetic spectra than the standard Mo/Mo combination are recommended for thicker breast, in order to reduce the breast dose levels. (author)

  14. In Vitro Comparison of Cone Beam Computed Tomography with Digital Periapical Radiography for Detection of Vertical Root Fracture in Posterior Teeth

    Mehrdad Abdinian

    2016-06-01

    Full Text Available Statement of the Problem: The diagnosis of vertical root fracture (VRF is a challenging task. Purpose: This in vitro study compared cone beam computed tomography (CBCT imaging with digital periapical radi-ography (DPR made by three different horizontal angels (20°mesial, 0° and 20° distal for accurate diagnosis of VRF. Materials and Method: Among 120 posterior teeth included in this study, 60 were vertically fractured. Fractured and non-fractured teeth were randomly distributed into three groups defined as group 1 with no filling in the root canal, group 2 with gutta-percha in the canal, and group 3 with the intracanal post. All samples were placed in a dry mandible and imaged with CBCT and DPR techniques. Two blind observers investigated the images. Results: CBCT had higher sensitivity but lower specificity compared with DPR, except for the intracanal post group in which the sensitivity of DPR was higher; though the chi-square test showed the differences to be statistically insignifi-cant. The sensitivity, specificity, and accuracy of CBCT and DPR were reduced in the cases that gutta-percha or post were present in the canal. Inter-observer agreement was higher for CBCT. A set of three DPRs with different horizontal angels were significantly more sensitive for VRF recognition than a single orthogonal DPR. Conclusion: Based on our results, there was no significant difference between CBCT and a set of three DPRs with dif-ferent angulations for VRF detection in posterior teeth. Therefore, it is suggested to consider DPRs with three different horizontal angels (20°mesial, 0° and 20° distal for radiographic evaluation before CBCT examination.

  15. In Vitro Comparison of Cone Beam Computed Tomography with Digital Periapical Radiography for Detection of Vertical Root Fracture in Posterior Teeth

    Abdinian, Mehrdad; Razavian, Hamid; Jenabi, Nastaran

    2016-01-01

    Statement of the Problem The diagnosis of vertical root fracture (VRF) is a challenging task. Purpose This in vitro study compared cone beam computed tomography (CBCT) imaging with digital periapical radiography (DPR) made by three different horizontal angels (20°mesial, 0° and 20° distal) for accurate diagnosis of VRF. Materials and Method Among 120 posterior teeth included in this study, 60 were vertically fractured. Fractured and non-fractured teeth were randomly distributed into three groups defined as group 1 with no filling in the root canal, group 2 with gutta-percha in the canal, and group 3 with the intracanal post. All samples were placed in a dry mandible and imaged with CBCT and DPR techniques. Two blind observers investigated the images. Results CBCT had higher sensitivity but lower specificity compared with DPR, except for the intracanal post group in which the sensitivity of DPR was higher; though the chi-square test showed the differences to be statistically insignificant. The sensitivity, specificity, and accuracy of CBCT and DPR were reduced in the cases that gutta-percha or post were present in the canal. Inter-observer agreement was higher for CBCT. A set of three DPRs with different horizontal angels were significantly more sensitive for VRF recognition than a single orthogonal DPR. Conclusion Based on our results, there was no significant difference between CBCT and a set of three DPRs with different angulations for VRF detection in posterior teeth. Therefore, it is suggested to consider DPRs with three different horizontal angels (20°mesial, 0° and 20° distal) for radiographic evaluation before CBCT examination. PMID:27284552

  16. Personal Computer Transport Analysis Program

    DiStefano, Frank, III; Wobick, Craig; Chapman, Kirt; McCloud, Peter

    2012-01-01

    The Personal Computer Transport Analysis Program (PCTAP) is C++ software used for analysis of thermal fluid systems. The program predicts thermal fluid system and component transients. The output consists of temperatures, flow rates, pressures, delta pressures, tank quantities, and gas quantities in the air, along with air scrubbing component performance. PCTAP s solution process assumes that the tubes in the system are well insulated so that only the heat transfer between fluid and tube wall and between adjacent tubes is modeled. The system described in the model file is broken down into its individual components; i.e., tubes, cold plates, heat exchangers, etc. A solution vector is built from the components and a flow is then simulated with fluid being transferred from one component to the next. The solution vector of components in the model file is built at the initiation of the run. This solution vector is simply a list of components in the order of their inlet dependency on other components. The component parameters are updated in the order in which they appear in the list at every time step. Once the solution vectors have been determined, PCTAP cycles through the components in the solution vector, executing their outlet function for each time-step increment.

  17. CT based radiography simulations for both industrial and medical radiography

    One of the important issues in the simulation work is proper representation of the simulated objects. The geometrical shapes of the simulated objects may range from very simple to very complicated geometries. In addition, a lot of objects come with heterogeneous material properties that need to be included into simulations. These two issues play important roles in both industrial and medical radiography simulations. CT (computed tomography) became widely available to the radiography community in the recent years. Since this technology provides two-dimensional images, CT images can be used to build models toward using in simulation work. In this work, we developed a CT image based algorithm to account for object shape complexities and heterogeneities. The resulting algorithm and absorbed energy doses in a human body part and ideal detector images obtained through the algorithm will be presented

  18. Digital radiography

    Precht, H; Gerke, O; Rosendahl, K;

    2012-01-01

    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...

  19. Comparison of Cone-Beam Computed Tomography and Periapical Radiography in Predicting Treatment Decision for Periapical Lesions: A Clinical Study

    Ashok Balasundaram

    2012-01-01

    Full Text Available Objectives. To compare the ability of endodontists to determine the size of apical pathological lesions and select the most appropriate choice of treatment based on lesions’ projected image characteristics using 2 D and 3 D images. Study Design. Twenty-four subjects were selected. Radiographic examination of symptomatic study teeth with an intraoral periapical radiograph revealed periapical lesions equal to or greater than 3 mm in the greatest diameter. Cone-beam Computed tomography (CBCT images were made of the involved teeth after the intraoral periapical radiograph confirmed the size of lesion to be equal to greater than 3 mm. Six observers (endodontists viewed both the periapical and CBCT images. Upon viewing each of the images from the two imaging modalities, observers (1 measured lesion size and (2 made decisions on treatment based on each radiograph. Chi-square test was used to look for differences in the choice of treatment among observers. Results. No significant difference was noted in the treatment plan selected by observers using the two modalities (χ2(3=.036, P>0.05. Conclusion. Lesion size and choice of treatment of periapical lesions based on CBCT radiographs do not change significantly from those made on the basis of 2 D radiographs.

  20. Multiple-image radiography

    Wernick, Miles N.; Wirjadi, Oliver; Chapman, Dean; Zhong, Zhong; Galatsanos, Nikolas P.; Yang, Yongyi; Brankov, Jovan G.; Oltulu, Oral; Anastasio, Mark A.; Muehleman, Carol

    2003-12-01

    Conventional radiography produces a single image of an object by measuring the attenuation of an x-ray beam passing through it. When imaging weakly absorbing tissues, x-ray attenuation may be a suboptimal signature of disease-related information. In this paper we describe a new phase-sensitive imaging method, called multiple-image radiography (MIR), which is an improvement on a prior technique called diffraction-enhanced imaging (DEI). This paper elaborates on our initial presentation of the idea in Wernick et al (2002 Proc. Int. Symp. Biomed. Imaging pp 129-32). MIR simultaneously produces several images from a set of measurements made with a single x-ray beam. Specifically, MIR yields three images depicting separately the effects of refraction, ultra-small-angle scatter and attenuation by the object. All three images have good contrast, in part because they are virtually immune from degradation due to scatter at higher angles. MIR also yields a very comprehensive object description, consisting of the angular intensity spectrum of a transmitted x-ray beam at every image pixel, within a narrow angular range. Our experiments are based on data acquired using a synchrotron light source; however, in preparation for more practical implementations using conventional x-ray sources, we develop and evaluate algorithms designed for Poisson noise, which is characteristic of photon-limited imaging. The results suggest that MIR is capable of operating at low photon count levels, therefore the method shows promise for use with conventional x-ray sources. The results also show that, in addition to producing new types of object descriptions, MIR produces substantially more accurate images than its predecessor, DEI. MIR results are shown in the form of planar images of a phantom and a biological specimen. A preliminary demonstration of the use of MIR for computed tomography is also presented.

  1. Comparison of chest radiography and high-resolution computed tomography findings in early and low-grade coal worker's pneumoconiosis

    Introduction: High-resolution computed tomography (HRCT) is more sensitive than chest X-ray (CXR) in the depiction of parenchymal abnormalities. We aimed to present and compare CXR and HRCT findings in coal workers with and without early and low-grade coal worker's pneumoconiosis (CWP). Materials and Methods: 71 coal workers were enrolled in this study. All workers were male. The CXR and HRCT of those workers were obtained and graded by two trained readers. HRCT's were graded according to Hosoda and Shida's Japanese classification. After grading, 67 workers with CXR profusion 0/0-2/2 were included in the study. Four patients with major opacity were excluded. Profusion 0/1 to 1/1 cases were accepted as early and profusion 1/2 and 2/2 cases as low-grade pneumoconiosis. Results: Discordance between CXR and HRCT was high. Discordance rate was found higher in the early pneumoconiosis cases with negative CXR than low-grade pneumoconiosis (60, 36 and 8%, respectively). When coal miners with normal CXR were evaluated by HRCT, six out of 10 cases were diagnosed as positive. In low-grade pneumoconiosis group, the number of patients with positive CXR but negative HRCT were low in comparison to patients with CXR negative and early pneumoconiosis findings. Most of the CXR category 0 patients (10/16) were diagnosed as category 1 by HRCT. Eleven cases diagnosed as CXR category 1 were diagnosed as category 0 (7/11) and category 2 (4/11) by HRCT. In CXR category 2 (eight cases), there were four cases diagnosed as category 1 by HRCT. Conclusions: Discordance between CXR and HRCT was high, especially for CXR negative and early pneumoconiosis cases. The role of CXR in screening coal workers to detect early pneumoconiosis findings should be questioned. We suggest using HRCT as a standard screening method instead of CXR to distinguish between normal and early pneumoconiosis

  2. Statistical Uncertainty in Quantitative Neutron Radiography

    Piegsa, Florian M.; Kaestner, Anders P.

    2016-01-01

    We demonstrate a novel procedure to calibrate neutron detection systems commonly used in standard neutron radiography. This calibration allows determining the uncertainties due to Poisson-like neutron counting statistics for each individual pixel of a radiographic image. The obtained statistical errors are necessary in order to perform correct quantitative analysis. This fast and convenient method is applied to real data measured at the cold neutron radiography facility ICON at the Paul Scher...

  3. Wavelet analysis methods for radiography of multidimensional growth of planar mixing layers

    Merritt, E. C.; Doss, F. W.

    2016-07-01

    The counter-propagating shear campaign is examining instability growth and its transition to turbulence in the high-energy-density physics regime using a laser-driven counter-propagating flow platform. In these experiments, we observe consistent complex break-up of and structure growth in a tracer layer placed at the shear flow interface during the instability growth phase. We present a wavelet-transform based analysis technique capable of characterizing the scale- and directionality-resolved average intensity perturbations in static radiographs of the experiment. This technique uses the complete spatial information available in each radiograph to describe the structure evolution. We designed this analysis technique to generate a two-dimensional power spectrum for each radiograph from which we can recover information about structure widths, amplitudes, and orientations. The evolution of the distribution of power in the spectra for an experimental series is a potential metric for quantifying the structure size evolution as well as a system's evolution towards isotropy.

  4. Digital chest radiography

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

    2015-01-01

    Purpose: Quality improvement of basic radiography focusing 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 of age are included in the study. The clinical research is performed between September and November 2014 where 3rd year Radiography students collect data on four Danish x-ray departments using identical procedures under guidance of...... conference. Conclusion: Collimation improvement in basic chest radiography can reduce the radiation to female patients at chest x-ray examinations....

  5. Digital chest radiography

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

    2015-01-01

    Background: Chest radiography is one of the most common examinations in radiology departments. In 2013 approximately 80,000 chest x-rays were performed on women in the fertile age. Even low dose for the examinationCorrect collimation Purpose: Quality improvement of basic radiography focusing 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...... of age are included in the study. The clinical research is performed between September and November 2014 where 3rd year Radiography students collect data on four Danish x-ray departments using identical procedures under guidance of clinical supervisors. Optimal collimation is determined by European...

  6. ROC-analysis of detection performance by analogue and digital plain film systems in chest radiography

    Purpose: To compare the performances of 4 imaging systems in the diagnostic radiology of the chest: an asymmetric screen-film combination (a-SFC); a conventional screen-film combination of speed class 200 (SFC); a screen-film combination of speed class 200 with an aluminum lung filter; a digital luminescence radiographs (DLR). Material and Methods: Object detectability studies were carried out using an anthropomorphic chest phantom. The images were obtained under standard exposure conditions at 125 kVp. The detection performance of the various systems was evaluated by receiver operating characteristic (ROC) analysis on the basis of a total of 12 240 observations. Results: In the overall evaluation the a-SFC and the SFC plus lung filter received equally high ratings of 0.878±0.018 and 0.860±0.21, respectively (p>0.05). There was no significant difference between the 200-speed SFC and the storage phosphor radiographs. In the mediastinum all the tested systems were clearly superior to the 200-speed SFC (p0.05). Conclusion: The a-SFC and the digital luminescence radiographs provide a significant gain in diagnostic information in the mediastinum without diminishing detail detectability in the lung fields and without additional radiation exposure. (orig.)

  7. Assessment of image quality in orthopaedic radiography with digital detectors: a visual grading analysis

    Decoster, Robin; Mol, Harrie; van den Broeck, Renaat; Smits, Dirk

    2013-03-01

    Background: The introduction of digital detectors in the radiology predicted a dose reduction. Due to the dynamic range, radiographs of sufficient quality can be produced with a lower detector air kerma (DAK). However, this reduction was not observed. Some authors indicate a creep towards higher DAK, explained by a better appreciation of the radiographs due to a higher contrast-to-noise ratio. Methodology: To investigate the relation between the DAK and the appreciation of image quality by radiologists, 172 anterior-posterior (AP) radiographs of the knee and 152 radiographs of the pelvis were collected in 19 radiology centres. A Visual Grading Analysis (VGA) with a five-point scale was used to judge the image quality of seven different anatomic structures. The mid-point of the scale (3) was equalized to diagnostic image quality. Six experienced radiologists scored both datasets, in a controlled environment, with ViewDex®. Every observer received instructions and a training dataset. Moreover, twenty radiographs were repeated to determine intra-observer variability. Results: The intra-observer variability was not significant (p>0.05) for both datasets. The knee AP obtained a VGAS score of 3.91, the pelvis AP obtained a VGAS score of 3.71. In both cases, the inter-observer correlation was high and significant. The correlation between the VGAS and the DAK (0.41μGy - 6.18μGy) was not significant in either of the cases; neither did other analysises based on technical parameters. Conclusion: The VGA revealed an image quality higher than diagnostic necessary. Based on the DAK, an overexposure is suspected. The relation between DAK and the appreciation has to be further investigated in detail.

  8. Screening of miners and millers at decreasing levels of asbestos exposure: comparison of chest radiography and thin-section computed tomography.

    Mario Terra-Filho

    Full Text Available Chest radiography (CXR is inferior to Thin-section computed tomography in the detection of asbestos related interstitial and pleural abnormalities. It remains unclear, however, whether these limitations are large enough to impair CXR´s ability in detecting the expected reduction in the frequency of these asbestos-related abnormalities (ARA as exposure decreases.Clinical evaluation, CXR, Thin-section CT and spirometry were obtained in 1418 miners and millers who were exposed to progressively lower airborne concentrations of asbestos. They were separated into four groups according to the type, period and measurements of exposure and/or procedures for controlling exposure: Group I (1940-1966/tremolite and chrysotile, without measurements of exposure and procedures for controlling exposure; Group II (1967-1976/chrysotile only, without measurements of exposure and procedures for controlling exposure; Group III (1977-1980/chrysotile only, initiated measurements of exposure and procedures for controlling exposure and Group IV (after 1981/chrysotile only, implemented measurements of exposure and a comprehensive procedures for controlling exposure.In all groups, CXR suggested more frequently interstitial abnormalities and less frequently pleural plaques than observed on Thin-section CT (p<0.050. The odds for asbestosis in groups of decreasing exposure diminished to greater extent at Thin-section CT than on CXR. Lung function was reduced in subjects who had pleural plaques evident only on Thin-section CT (p<0.050. In a longitudinal evaluation of 301 subjects without interstitial and pleural abnormalities on CXR and Thin-section CT in a previous evaluation, only Thin-section CT indicated that these ARA reduced as exposure decreased.CXR compared to Thin-section CT was associated with false-positives for interstitial abnormalities and false-negatives for pleural plaques, regardless of the intensity of asbestos exposure. Also, CXR led to a substantial

  9. An analysis of the experiences of radiography and radiotherapy students who are carers at one UK university

    Purpose: This is a mixed methods study of the experiences and attendance of radiography and radiotherapy students who are carers at one UK university, Undergraduate radiography and radiotherapy programmes are attracting increasing numbers of mature students. It is therefore likely that the number of students with carer responsibilities is also increasing. This study explores the experiences of higher education of students with caring responsibilities. The aim of the study is to identify possible strategies and practices to enhance the student experience and so to work towards compliance with the recent Equality Act 2010. Method: All students on the radiography (n = 130) and radiotherapy (n = 97) programmes were invited to complete a short questionnaire. Students who identified themselves as carers on the questionnaire were invited to participate in focus group sessions. Due to the issues raised in the focus groups by students with regard to attendance at university and clinical placement, student absence rates were also investigated for students with and without caring responsibilities. Results: 215 students completed the questionnaire. 30 of the 215 students identified themselves as carers. 18 carers agreed to take part in focus groups. Carers reported that having fees paid by the NHS was an important choice factor for higher education. Carers' main concerns were: timetabling, finances, support after exam failures, understanding from academic staff and attendance issues. Examination of absence rates demonstrated carers had significantly (p = 0.000) less absence than non-carers for radiography and no significant differences for radiotherapy (p = 0.105). Conclusion: The NHS states it must be reflective of the community it serves. Thus those responsible for delivering health professional programmes have a duty to recruit and retain a diverse student population. The introduction of the Equality Act 2010 means higher education institutions must consider the needs of

  10. Numerical Analysis of Multiscale Computations

    Engquist, Björn; Tsai, Yen-Hsi R

    2012-01-01

    This book is a snapshot of current research in multiscale modeling, computations and applications. It covers fundamental mathematical theory, numerical algorithms as well as practical computational advice for analysing single and multiphysics models containing a variety of scales in time and space. Complex fluids, porous media flow and oscillatory dynamical systems are treated in some extra depth, as well as tools like analytical and numerical homogenization, and fast multipole method.

  11. Interactive computer programs in sequence data analysis.

    Jagadeeswaran, P; McGuire, P M

    1982-01-01

    We present interactive computer programs for the analysis of nucleic acid sequences. In order to handle these programs, minimum computer experience is sufficient. The nucleotide sequence of the human gamma globin gene complex is used as an example to illustrate the data analysis.

  12. Neutron radiography, techniques and applications

    After describing the principles of the ''in pool'' and ''dry'' installations, techniques used in neutron radiography are reviewed. Use of converter foils with silver halide films for the direct and transfer methods is described. Advantages of the use of nitrocellulose film for radiographying radioactive objects are discussed. Dynamic imaging is shortly reviewed. Standardization in the field of neutron radiography (ASTM and Euratom Neutron Radiography Working Group) is described. The paper reviews main fields of use of neutron radiography. Possibilities of use of neutron radiography at research reactors in various scientific, industrial and other fields are mentioned. Examples are given of application of neutron radiography in industry and the nuclear field. (author)

  13. International Neutron Radiography Newsletter

    Domanus, Joseph Czeslaw

    1986-01-01

    At the First World Conference on Neutron Radiography i t was decided to continue the "Neutron Radiography Newsletter", published previously by J.P. Barton, as the "International Neutron Radiography Newsletter" (INRNL), with J.C. Doraanus as editor. The British Journal of Non-Destructive Testing (BJNDT) has agreed to publish the INRNL in i t s column "NDT Bookcase". The Revue Practique de Control Industriel has also agreed to publish the French version of the INRNL. Up t i l l now 12 issues of...

  14. Recent developments in radiography

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

  15. Computational methods for global/local analysis

    Ransom, Jonathan B.; Mccleary, Susan L.; Aminpour, Mohammad A.; Knight, Norman F., Jr.

    1992-01-01

    Computational methods for global/local analysis of structures which include both uncoupled and coupled methods are described. In addition, global/local analysis methodology for automatic refinement of incompatible global and local finite element models is developed. Representative structural analysis problems are presented to demonstrate the global/local analysis methods.

  16. Adjustment computations spatial data analysis

    Ghilani, Charles D

    2011-01-01

    the complete guide to adjusting for measurement error-expanded and updated no measurement is ever exact. Adjustment Computations updates a classic, definitive text on surveying with the latest methodologies and tools for analyzing and adjusting errors with a focus on least squares adjustments, the most rigorous methodology available and the one on which accuracy standards for surveys are based. This extensively updated Fifth Edition shares new information on advances in modern software and GNSS-acquired data. Expanded sections offer a greater amount of computable problems and their worked solu

  17. Industrial Radiography Safety in Australia

    The first applications of the imaging capability of X-rays were non-medical. Roentgen produced images of his shotgun, a compass and a set of weights in a closed box to show his colleagues. Prior to 1912, X-rays were used little outside the realms of medicine and dentistry because the X-ray tubes failed under the higher voltages required for industrial purposes. However, that changed in 1913 when high vacuum X-ray tubes designed by Coolidge became available. In 1922, industrial radiography took another step forward with the advent of the 200,000-volt X-ray tube that allowed radiographs of thick steel parts to be produced in a reasonable amount of time. In 1931 the American Society of Mechanical Engineers (ASME) permitted approval of fusion welded pressure vessels by x-ray, which promoted an acceptance and use of the method. That application continues. Radium became the initial gamma ray source for industrial radiography. The material allowed radiography of castings up to 30cm thick. During World War II, industrial radiography grew significantly as part of the US Navy's shipbuilding-program, and in 1946 gamma ray sources such as cobalt 60 and iridium 192 became available. These new sources gained rapid popularity because they emitted more intense radiation than radium and were less expensive. Present state: the majority of industrial radiography techniques have changed little since their inception. An image is captured, processed and analysed for evidence of fault or defect. Today however, the images are of higher quality and greater sensitivity, through the use of better quality films, smaller radiation sources and automated processing. Developments in electronics and computers now allow technicians to create a digital image, enhance it, transmit it or store it indefinitely. The most noticeable change in industrial radiography equipment from the technician's view would be the reduction in weight of the equipment for a given kV output. Never the less it remains

  18. Rhinoceros Feet Step Out of a Rule-of-Thumb: A Wildlife Imaging Pioneering Approach of Synchronized Computed Tomography-Digital Radiography

    Galateanu, Gabriela; Hermes, Robert; Saragusty, Joseph; Göritz, Frank; Potier, Romain; Mulot, Baptiste; Maillot, Alexis; Etienne, Pascal; Bernardino, Rui; Fernandes, Teresa; Mews, Jurgen; Hildebrandt, Thomas Bernd

    2014-01-01

    Currently, radiography is the only imaging technique used to diagnose bone pathology in wild animals situated under “field conditions”. Nevertheless, while chronic foot disease in captive mega-herbivores is widely reported, foot radiographic imaging is confronted with scarcity of studies. Numerous hindrances lead to such limited numbers and it became very clear that the traditional perspective on bone imaging in domestic animals based on extensive studies and elaborated statistical evaluation...

  19. Lesion detectability in digital radiography

    Gagne, Robert M.; Boswell, Jonathan S.; Myers, Kyle J.; Peter, Guillaume

    2001-06-01

    The usefulness of Fourier-based measures of imaging performance has come into question for the evaluation of digital imaging systems. Figures of merit such as detective quantum efficiency are relevant for linear, shift-invariant systems with stationary noise. However, no digital imaging system is shift invariant, and realistic images do not satisfy the stationarity condition. Our methods for task- based evaluation of imaging systems, based on lesion detectability, do not require such assumptions. We have computed the performance of Hotelling and nonprewhitening matched-filter observers for the task of lesion detection in digital radiography.

  20. Impact analysis on a massively parallel computer

    Advanced mathematical techniques and computer simulation play a major role in evaluating and enhancing the design of beverage cans, industrial, and transportation containers for improved performance. Numerical models are used to evaluate the impact requirements of containers used by the Department of Energy (DOE) for transporting radioactive materials. Many of these models are highly compute-intensive. An analysis may require several hours of computational time on current supercomputers despite the simplicity of the models being studied. As computer simulations and materials databases grow in complexity, massively parallel computers have become important tools. Massively parallel computational research at the Oak Ridge National Laboratory (ORNL) and its application to the impact analysis of shipping containers is briefly described in this paper

  1. The importance of conventional radiography in the mutational analysis of skeletal dysplasias (the TRPV4 mutational family)

    Nemec, Stefan F.; Cohn, Daniel H.; Krakow, Deborah; Funari, Vincent A.; Rimoin, David L.; Lachman, Ralph S. [Medical Genetics Institute, Cedars Sinai Medical Center, International Skeletal Dysplasia Registry, Los Angeles, CA (United States)

    2012-01-15

    The spondylo and spondylometaphyseal dysplasias (SMDs) are characterized by vertebral changes and metaphyseal abnormalities of the tubular bones, which produce a phenotypic spectrum of disorders from the mild autosomal-dominant brachyolmia to SMD Kozlowski to autosomal-dominant metatropic dysplasia. Investigations have recently drawn on the similar radiographic features of those conditions to define a new family of skeletal dysplasias caused by mutations in the transient receptor potential cation channel vanilloid 4 (TRPV4). This review demonstrates the significance of radiography in the discovery of a new bone dysplasia family due to mutations in a single gene. (orig.)

  2. High quality neutron radiography

    By the neutron radiography which is reported in this paper, the radiographs which cannot be obtained by X-ray radiography such as the distribution of water flow in a metal vessel or high radioactive substances can be obtained. As the imaging methods of neutron radiography, there are TV method, film method, track etching method and so on. As for these devices, the dynamic range is small, and there is the limit in quantitative evaluation. Consequently, the semiconductor light-receiving element made by Hamamatsu Photonics K.K. developed for measuring weak light was used as a new device. It is called PCD linear image sensor as a plasma coupled device (PCD) is used as the shift register. The basic research on imaging neutron flux distribution by using a cooled type PCD linear image sensor and a honeycomb collimator and analyzing it quantitatively was carried out. The principle of neutron radiography, the PCD linear image sensor system and its cooling unit, the principle and the method of quantitative neutron radiography, the experiment on neutron radiography and its results, and the example of the application to CT are reported. (K.I.)

  3. Applied time series analysis and innovative computing

    Ao, Sio-Iong

    2010-01-01

    This text is a systematic, state-of-the-art introduction to the use of innovative computing paradigms as an investigative tool for applications in time series analysis. It includes frontier case studies based on recent research.

  4. Muscle parameters estimation based on biplanar radiography.

    Dubois, G; Rouch, P; Bonneau, D; Gennisson, J L; Skalli, W

    2016-11-01

    The evaluation of muscle and joint forces in vivo is still a challenge. Musculo-Skeletal (musculo-skeletal) models are used to compute forces based on movement analysis. Most of them are built from a scaled-generic model based on cadaver measurements, which provides a low level of personalization, or from Magnetic Resonance Images, which provide a personalized model in lying position. This study proposed an original two steps method to access a subject-specific musculo-skeletal model in 30 min, which is based solely on biplanar X-Rays. First, the subject-specific 3D geometry of bones and skin envelopes were reconstructed from biplanar X-Rays radiography. Then, 2200 corresponding control points were identified between a reference model and the subject-specific X-Rays model. Finally, the shape of 21 lower limb muscles was estimated using a non-linear transformation between the control points in order to fit the muscle shape of the reference model to the X-Rays model. Twelfth musculo-skeletal models were reconstructed and compared to their reference. The muscle volume was not accurately estimated with a standard deviation (SD) ranging from 10 to 68%. However, this method provided an accurate estimation the muscle line of action with a SD of the length difference lower than 2% and a positioning error lower than 20 mm. The moment arm was also well estimated with SD lower than 15% for most muscle, which was significantly better than scaled-generic model for most muscle. This method open the way to a quick modeling method for gait analysis based on biplanar radiography. PMID:27082150

  5. Intercomparison of inductively coupled plasma mass spectrometry, quantitative neutron capture radiography, and prompt gamma activation analysis for the determination of boron in biological samples.

    Schütz, C L; Brochhausen, C; Hampel, G; Iffland, D; Kuczewski, B; Otto, G; Schmitz, T; Stieghorst, C; Kratz, J V

    2012-10-01

    Boron determination in blood and tissue samples is a crucial task especially for treatment planning, preclinical research, and clinical application of boron neutron capture therapy (BNCT). Comparison of clinical findings remains difficult due to a variety of analytical methods, protocols, and standard reference materials in use. This paper addresses the comparability of inductively coupled plasma mass spectrometry, quantitative neutron capture radiography, and prompt gamma activation analysis for the determination of boron in biological samples. It was possible to demonstrate that three different methods relying on three different principles of sample preparation and boron detection can be validated against each other and yield consistent results for both blood and tissue samples. The samples were obtained during a clinical study for the application of BNCT for liver malignancies and therefore represent a realistic situation for boron analysis. PMID:22918535

  6. Intercomparison of inductively coupled plasma mass spectrometry, quantitative neutron capture radiography, and prompt gamma activation analysis for the determination of boron in biological samples

    Schuetz, C.L. [University of Mainz, Institute for Nuclear Chemistry, Mainz (Germany); Johannes Gutenberg-University of Mainz, Institute for Nuclear Chemistry, Mainz (Germany); Brochhausen, C. [University of Mainz, Institute of Pathology, Mainz (Germany); Hampel, G.; Iffland, D.; Schmitz, T.; Stieghorst, C.; Kratz, J.V. [University of Mainz, Institute for Nuclear Chemistry, Mainz (Germany); Kuczewski, B. [Regional Council Darmstadt, Darmstadt (Germany); Otto, G. [University of Mainz, Department of Hepatobiliary, Pancreatic and Transplantation Surgery, Mainz (Germany)

    2012-10-15

    Boron determination in blood and tissue samples is a crucial task especially for treatment planning, preclinical research, and clinical application of boron neutron capture therapy (BNCT). Comparison of clinical findings remains difficult due to a variety of analytical methods, protocols, and standard reference materials in use. This paper addresses the comparability of inductively coupled plasma mass spectrometry, quantitative neutron capture radiography, and prompt gamma activation analysis for the determination of boron in biological samples. It was possible to demonstrate that three different methods relying on three different principles of sample preparation and boron detection can be validated against each other and yield consistent results for both blood and tissue samples. The samples were obtained during a clinical study for the application of BNCT for liver malignancies and therefore represent a realistic situation for boron analysis. (orig.)

  7. Intercomparison of inductively coupled plasma mass spectrometry, quantitative neutron capture radiography, and prompt gamma activation analysis for the determination of boron in biological samples

    Boron determination in blood and tissue samples is a crucial task especially for treatment planning, preclinical research, and clinical application of boron neutron capture therapy (BNCT). Comparison of clinical findings remains difficult due to a variety of analytical methods, protocols, and standard reference materials in use. This paper addresses the comparability of inductively coupled plasma mass spectrometry, quantitative neutron capture radiography, and prompt gamma activation analysis for the determination of boron in biological samples. It was possible to demonstrate that three different methods relying on three different principles of sample preparation and boron detection can be validated against each other and yield consistent results for both blood and tissue samples. The samples were obtained during a clinical study for the application of BNCT for liver malignancies and therefore represent a realistic situation for boron analysis. (orig.)

  8. Computational methods in power system analysis

    Idema, Reijer

    2014-01-01

    This book treats state-of-the-art computational methods for power flow studies and contingency analysis. In the first part the authors present the relevant computational methods and mathematical concepts. In the second part, power flow and contingency analysis are treated. Furthermore, traditional methods to solve such problems are compared to modern solvers, developed using the knowledge of the first part of the book. Finally, these solvers are analyzed both theoretically and experimentally, clearly showing the benefits of the modern approach.

  9. Distributed computing and nuclear reactor analysis

    Large-scale scientific and engineering calculations for nuclear reactor analysis can now be carried out effectively in a distributed computing environment, at costs far lower than for traditional mainframes. The distributed computing environment must include support for traditional system services, such as a queuing system for batch work, reliable filesystem backups, and parallel processing capabilities for large jobs. All ANL computer codes for reactor analysis have been adapted successfully to a distributed system based on workstations and X-terminals. Distributed parallel processing has been demonstrated to be effective for long-running Monte Carlo calculations

  10. Recovering root system traits using image analysis exemplified by two-dimensional neutron radiography images of lupine.

    Leitner, Daniel; Felderer, Bernd; Vontobel, Peter; Schnepf, Andrea

    2014-01-01

    Root system traits are important in view of current challenges such as sustainable crop production with reduced fertilizer input or in resource-limited environments. We present a novel approach for recovering root architectural parameters based on image-analysis techniques. It is based on a graph representation of the segmented and skeletonized image of the root system, where individual roots are tracked in a fully automated way. Using a dynamic root architecture model for deciding whether a specific path in the graph is likely to represent a root helps to distinguish root overlaps from branches and favors the analysis of root development over a sequence of images. After the root tracking step, global traits such as topological characteristics as well as root architectural parameters are computed. Analysis of neutron radiographic root system images of lupine (Lupinus albus) grown in mesocosms filled with sandy soil results in a set of root architectural parameters. They are used to simulate the dynamic development of the root system and to compute the corresponding root length densities in the mesocosm. The graph representation of the root system provides global information about connectivity inside the graph. The underlying root growth model helps to determine which path inside the graph is most likely for a given root. This facilitates the systematic investigation of root architectural traits, in particular with respect to the parameterization of dynamic root architecture models. PMID:24218493

  11. Automating sensitivity analysis of computer models using computer calculus

    An automated procedure for performing sensitivity analysis has been developed. The procedure uses a new FORTRAN compiler with computer calculus capabilities to generate the derivatives needed to set up sensitivity equations. The new compiler is called GRESS - Gradient Enhanced Software System. Application of the automated procedure with direct and adjoint sensitivity theory for the analysis of non-linear, iterative systems of equations is discussed. Calculational efficiency consideration and techniques for adjoint sensitivity analysis are emphasized. The new approach is found to preserve the traditional advantages of adjoint theory while removing the tedious human effort previously needed to apply this theoretical methodology. Conclusions are drawn about the applicability of the automated procedure in numerical analysis and large-scale modelling sensitivity studies

  12. Time of flight fast neutron radiography

    Neutron radiography with fast or thermal neutrons is a standard technique for non-destructive testing (NDT). Here we report results for fast neutron radiography both as an adjunct to pulsed fast neutron analysis (PFNA) and as a stand-alone method for NDT. PFNA is a new technique for utilizing a collimated pulsed neutron beam to interrogate items and determine their elemental composition. By determining the time of flight for gamma-rays produced by (n,n' gamma X) reactions, a three dimensional image can be produced. Neutron radiography data taken with the same beam provides an important constraint for image reconstruction, and in particular is important in inferring the amount of hydrogen within the interrogated item. As a stand-alone device, the radiography measurement can be used to image items as large as cargo containers as long as their density is not too high. The use of a pulsed beam gives the further advantage of a time of flight measurement on the transmitted neutrons. By gating the radiography signal on the time of flight appropriate to the energy of the primary neutrons, most build-up from scattered neutrons can be eliminated. The pulsed beam also greatly improves the signal to background and extends the range of the neutron radiography. Simulation results will be presented which display the advantage of this constraint in particular for statistically limited data. Experimental results will be presented which show some of the limitations likely in a PFNA system utilizing neutron radiography data. Experimental and simulation results will demonstrate possible uses for this type of radiographic data in identifying contraband substances such as drugs. (orig.)

  13. Radiography at CERN

    HSE Unit

    2014-01-01

    What is industrial radiography? It is a non-destructive method with a wide variety of applications, such as inspecting the quality of a weld. It uses high-energy radioactive sources or an X-ray generator.   Is this inspection technique used at CERN? Yes, it is widely used at CERN by the EN-MME Group, which outsources the work to one or more companies, depending on the workload. Is it possible to carry out radiography anywhere at CERN? Yes, it is possible to carry out radiography in any building/accelerator/experiment area at CERN (including in areas which are not normally subject to radiological hazards). When is radiography carried out? It normally takes place outside of working hours (7 p.m. to 6 a.m.). How will I know if radiography is taking place in my building? If this activity is planned in a CERN building, notices will be affixed to all of its main entrance doors at least 24 hours in advance. What are the risks? There is a risk of exposure to very high levels of radiation, dep...

  14. Proceedings of 7th short conference on neutron radiography

    The first short period conference on neutron radiography was held in 1970, and now the 7th meeting was held. The works to develop neutron radiography in Japan are as active as those in western countries, and the research is in progress by using neutrons from reactors, radioisotopes and accelerators in order to achieve the technology of high standard. In this conference, 26 papers and six comments were presented, and the themes covered the equipment for radiography, the practical application, and the related research. The second World Conference on Neutron Radiography will be held in Paris in June, 1986, and the further promotion of the spread of neutron radiography can be expected. The proceedings of the conference is published with the hope that joint effort and information exchange are further enhanced in coming years to develop the neutron radiography in Japan. The neutron radiography using the Kinki University reactor, the Rikkyo Triga-2 reactor, the Musashi reactor, the Kyoto research reactor, a 3MV Van de Graaff accelerator in Toyota, a subcompact cyclotron in Sumitomo, a baby cyclotron-dual collimator in National Space Development Agency and so on, Cf-252 based thermal neutron radiography, CT with Sb-124/Be neutrons, pulse power neutron source, imaging converters, neutron radiographic image processing, computed tomography using neutron television systems and others are reported. (Kako, I.)

  15. Analysis of radial radiography for the liner stability series at Pegasus: PGII-59, PGII-62, and PGII-63

    Recently, three liner stability experiments were performed at the Pegasus II pulsed power facility to determine the asymmetric variations in the material density of a cylindrical liner during an electro-magnetically driven implosion. The initial campaign consisted of three experiments, designated LS-1, LS-2, and LS-3. LS-1 and LS-2 were driven with a peak current of approximately 4.2 MA, whereas the peak current for LS-3 was approximately 6.4 MA. All three liners initially were 0.4 mm wall aluminum cylinders with a mean radius of 2.38 cm and a height of 2.0 cm. The inner surface of each liner was coated with a thin (18--23 microm) layer of gold to aid in the determination of the position of the inner surface of the liner. Radial radiography was used to characterize the z-dependent and θ-dependent instabilities that were observed as the liner contracted

  16. Automating sensitivity analysis of computer models using computer calculus

    An automated procedure for performing sensitivity analyses has been developed. The procedure uses a new FORTRAN compiler with computer calculus capabilities to generate the derivatives needed to set up sensitivity equations. The new compiler is called GRESS - Gradient Enhanced Software System. Application of the automated procedure with ''direct'' and ''adjoint'' sensitivity theory for the analysis of non-linear, iterative systems of equations is discussed. Calculational efficiency consideration and techniques for adjoint sensitivity analysis are emphasized. The new approach is found to preserve the traditional advantages of adjoint theory while removing the tedious human effort previously needed to apply this theoretical methodology. Conclusions are drawn about the applicability of the automated procedure in numerical analysis and large-scale modelling sensitivity studies. 24 refs., 2 figs

  17. Are radiography lecturers, leaders?

    This review article aims to explore the concept of radiography lecturers acting as leaders to their student followers. Through a brief review of the literature, a definition of leadership is suggested and some leadership theories explored. The path-goal theory, leader–member exchange theory and the contemporary theory of transformational leadership are examined more closely. Links between lecturer-leader behaviour and student motivation and learning are tentatively suggested with transformational leadership appearing to offer the optimal leadership style for lecturers to adopt. The paucity of literature relating directly to radiography is acknowledged and areas for further research are suggested. The article concludes with some of the author's practical ideas for incorporating transformational leadership styles and behaviours into radiography education today

  18. Radiography of pressure ulcers

    In patients with longstanding and/or deep pressure ulcers radiology is usually consulted. Survey radiography and sinography in 14 patients with pressure ulcers (6 over the tuber ischii and 8 over the femoral trochanter) were evaluated. Osteomyelitic involvement of adjacent bone was revealed in 9 patients on survey radiography. However, it was usually impossible to assess whether or not bony involvement represents healed or active osteomyelitis. Sinography did not contribute to the assessment of whether or not adjacent cortical bone was involved. However, when a fistulation to an adjacent joint was revealed this contributed substantially to the preoperative planning of resection. We therefore recommend that survey radiography and sinography should be included in the evaluation of these patients but that the results from such examinations are critically evaluated. Joint involvement should be taken seriously as progression of septic arthritis usually occurs rapidly. (orig.)

  19. Real-time radiography

    Real-time radiography is used for imaging both dynamic events and static objects. Fluorescent screens play an important role in converting radiation to light, which is then observed directly or intensified and detected. The radiographic parameters for real-time radiography are similar to conventional film radiography with special emphasis on statistics and magnification. Direct-viewing fluoroscopy uses the human eye as a detector of fluorescent screen light or the light from an intensifier. Remote-viewing systems replace the human observer with a television camera. The remote-viewing systems have many advantages over the direct-viewing conditions such as safety, image enhancement, and the capability to produce permanent records. This report reviews real-time imaging system parameters and components

  20. Computer analysis of ESR spectra

    Author. Isotropic ESR spectra often display complicated patterns which are difficult to analyze for their hyperfine splitting constants (HSC). To simplify the analysis, we have written a program suitable for PC's for sufficiently iterating simulations of isotropic ESR spectra and determining the simulation which fits the experimental spectra. Chapter one gives a brief introduction to the theory of electron spin resonance (ESR). In chapter two the main concepts of the program are presented. Auto simulate is the main algorithm. It calculates the entire field of valid simulations to ensure that the solution set contains all parameter combinations which produce satisfactory spectra. Auto simulate requires prior knowledge of the HSCs and other parameters needed for the simulation such as the line width, the spectrum width, and the number of magnetic nuclei. Proton Coupling Constant Extraction (PCCE) and autocorrelation are two methods complementing each other to determine the HSCs. Another iterative method based on a systematic application of Monte Carlo method can be applied to generate more accurate values of the line width. In chapter three, the spectra of Naphthalene, Tetracene, Indigo, Ox-indigo semi quinone, thio-indigo and 2,2'-dipyridyl-Na complex free radicals are analyzed. The results are compared to the literature value, good agreement is obtained for different resolution and noise to signal ratios. In the last chapter a print out of the program is presented. The programming language used is Microsoft QuickBASIC version 7.1

  1. 非晶硒平板探测器DR与CR模拟病变描述和剂量降低的对比研究%Amorphous selenium flat-panel detector digital radiography versus computed radiography: phantom study of depiction of simulated lesion and dose reduction

    曾勇明; 吴富荣; 张志伟; 欧阳羽; 谭秀洪; 金瑞

    2008-01-01

    Objective To compare an amorphous selenium fiat-panel detector digital radiography(DR) with a computed radiography(CR) for the depiction of simulated pulmonary lesion,as well as for evaluation of dose reduction.Methods Simulated linear,reticular,and nodular lesion were located in all anthropomorphic chest phantom.The phantom was exposed by DR and CR with different mAs sets.The entrance surface doses were recorded for all images.Hard copy images were generated at different dose levels.Images were presented in a random order to four independent radiologists.They subjectively rated the visibility of simulated pulmonary lesion. Statistical significance of difference was analvsed with wilcoxon test.Resuits The visibility of simulated linear and reticular lesions on the images obtained with DR was superior to the images from CR at 2.0 and 3.2 mAs.P 0.05).DR was superior to CR in detection sinail nodular(diameter0.05).2.0、3.2、5.0、6.3 mAs曝光档,对于小结节(直径小于10 mm)的检测DR均优于CR(Z:-2.237,P=0.018;Z=-2.384,P=0.017;Z=-2.388,P=0.017;Z=-2.366,P=0.018).当3种模拟肺部病变都显示清楚时.用非晶硒DR系统的入射体表剂量降低约65%.结论 对微小低对比病变的描述,非晶硒平板探测器DR优于CR且明显地降低曝光剂晕.

  2. Computer aided nonlinear electrical networks analysis

    Slapnicar, P.

    1977-01-01

    Techniques used in simulating an electrical circuit with nonlinear elements for use in computer-aided circuit analysis programs are described. Elements of the circuit include capacitors, resistors, inductors, transistors, diodes, and voltage and current sources (constant or time varying). Simulation features are discussed for dc, ac, and/or transient circuit analysis. Calculations are based on the model approach of formulating the circuit equations. A particular solution of transient analysis for nonlinear storage elements is described.

  3. Bone X-Ray (Radiography)

    Full Text Available ... Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small ... X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive medical ...

  4. Bone X-Ray (Radiography)

    Full Text Available ... Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small dose ... limitations of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is ...

  5. Bone X-Ray (Radiography)

    Full Text Available ... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

  6. Bone X-Ray (Radiography)

    ... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

  7. Computer graphics in reactor safety analysis

    This paper describes a family of three computer graphics codes designed to assist the analyst in three areas: the modelling of complex three-dimensional finite element models of reactor structures; the interpretation of computational results; and the reporting of the results of numerical simulations. The purpose and key features of each code are presented. The graphics output used in actual safety analysis are used to illustrate the capabilities of each code. 5 refs., 10 figs

  8. Interactive computer analysis of nuclear backscattering spectra

    A review will be made of computer-based interactive nuclear backscattering analysis system. Users without computer experience can develop moderate competence with the system after only brief instruction because of the menu-driven organization. Publishable quality figures can be obtained without any computer expertise. Among the quantities which can be displayed over the data are depth scales for any element, element identification, relative concentrations and theoretical spectra. Captions and titling can made from a selection of 30 font styles. Lettering is put on the graphs umder joy-stick control such that placement is exact without needing complicated commands. (orig.)

  9. Computer Language Effciency via Data Envelopment Analysis

    Andrea Ellero

    2011-01-01

    Full Text Available The selection of the computer language to adopt is usually driven by intuition and expertise, since it is very diffcult to compare languages taking into account all their characteristics. In this paper, we analyze the effciency of programming languages through Data Envelopment Analysis. We collected the input data from The Computer Language Benchmarks Game: we consider a large set of languages in terms of computational time, memory usage, and source code size. Various benchmark problems are tackled. We analyze the results first of all considering programming languages individually. Then, we evaluate families of them sharing some characteristics, for example, being compiled or interpreted.

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

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

  11. Computational structural analysis and finite element methods

    Kaveh, A

    2014-01-01

    Graph theory gained initial prominence in science and engineering through its strong links with matrix algebra and computer science. Moreover, the structure of the mathematics is well suited to that of engineering problems in analysis and design. The methods of analysis in this book employ matrix algebra, graph theory and meta-heuristic algorithms, which are ideally suited for modern computational mechanics. Efficient methods are presented that lead to highly sparse and banded structural matrices. The main features of the book include: application of graph theory for efficient analysis; extension of the force method to finite element analysis; application of meta-heuristic algorithms to ordering and decomposition (sparse matrix technology); efficient use of symmetry and regularity in the force method; and simultaneous analysis and design of structures.

  12. Statistical Uncertainty in Quantitative Neutron Radiography

    Piegsa, Florian M

    2016-01-01

    We demonstrate a novel procedure to calibrate neutron detection systems commonly used in standard neutron radiography. This calibration allows determining the uncertainties due to Poisson-like neutron counting statistics for each individual pixel of a radiographic image. The obtained statistical errors are necessary in order to perform correct quantitative analysis. This fast and convenient method is applied to real data measured at the cold neutron radiography facility ICON at the Paul Scherrer Institute. Moreover, from the results the effective neutron flux at the beam line is determined.

  13. Management Waste Of Of Radiography Of Personal Certification Process

    Have been conducted analysis of waste of Radiography Personnel Certification Level 1 and Level 2 to measure whether Certification NDE Radiography activity to effect environment or not. The result of waste analysis to be compared with standard is 0.05 ppm. Three locations are selected to get waste sample continuously are : Fixer Tank, Back of 71 Building and Control Main Drain Box. Result of analysis from three selected locations of waste flow have reduced silver containment. The Silver containment of waste to be release to environment is below 0.05 ppm; it means that Radiography of Personnel Certification Process is not effect environmental

  14. Pet fish radiography: technique and case history reports

    Radiography can be used to aid in the diagnosis and treatment of pet fish diseases. Handling, restraint and radiographic technique for the radiographic examination of pet fish is described. Quality diagnostic images can be obtained with standard radiographic equipment and radiographic techniques. Fishes with undifferentiated sarcoma, swim bladder herniation and scoliosis are three clinical examples that are described where radiography was used in the management of the patient. Conventional radiography appears to be best for evaluating skeletal and swim bladder diseases. Alternate imaging techniques such as computed tomography and magnetic resonance imaging may enhance the evaluation of coelomic soft tissue structures

  15. The stationary neutron radiography system

    To provide the high intensity neutron beam and support systems necessary for radiography, the Stationary Neutron Radiography System was constructed at McClellan Air Force Base. The Stationary Neutron Radiography System utilizes a one megawatt TRIGA reactor contained in an Aluminium tank surrounded by eight foot thick concrete walls. There are four neutron beam tubes at inclined angles from the reactor core to separate radiography bays. In three of the bays, robotic systems manipulate aircraft components in the neutron beam, while real-time imaging systems provide images concurrent with the irradiation. Film radiography of smaller components is performed in the remaining bay

  16. Accelerator-based neutron tomography cooperating with X-ray radiography

    Neutron resonance absorption spectroscopy (N-RAS) using a pulsed neutron source can be applied to time-of-flight (TOF) radiography, and the obtained parameters from the peak shape analysis can be reconstructed as the tomograms of nuclide distributions using computed tomography (CT). The problem is that the available spatial resolution is not sufficient for radiography imaging. In this study, we combined neutron and X-ray radiographies to improve the quantitative reconstruction of the neutron tomogram. The accelerator-based neutron source emits X-rays (or gamma-rays) at the same time the neutron pulse is emitted. We utilized the X-ray beam from the neutron source to obtain X-ray radiogram on the same beam line with neutron radiography and then reconstructed the neutron tomogram quantitatively with the help of a detailed sample internal structure obtained from the X-ray radiogram. We calculated the nuclide number density distribution tomogram using a statistical reconstruction procedure, which was easy to include in the structure model during the reconstruction. The obtained result of nuclide number density distribution showed good coincidence with the original object number density.

  17. Neutron radiography with cyclotron

    The technique using thermal neutrons was demanded because of its inspection ability to show hydrogeneous material such as plastics, water, explosives or composite materials and irradiated nuclear fuel capsules. This paper describes some experimental results and applications in neutron radiography by the use of several small cyclotrons producing neutrons by Be(p,n) reaction. (author)

  18. Ultrasonography X gamma radiography

    The accumulated experience in the last ten years of substitution to essays by gamma radiography to essay by ultrasonography, starting of the systematic comparison and tabulation of the results obtained by both essays applied in welding joints, in field, in steel pipelines of the SABESP. (V.R.B.)

  19. Scanning equalization radiography

    The invention is in the field of radiography and seeks to reduce the undesirable effects on a radiographic image due to variations in thickness of the irradiated object which cause large variations in exposure at the image plane that can exceed the practical or desirable exposure range of the film or other imaging medium. 17 figs

  20. Manual on industrial radiography

    This manual is intended as a source of educational material to personnel seeking certification as industrial radiographers, and as a guide and reference text for educational organizations that are providng courses in industrial radiography. It covers the basic principles of x-ray and gamma radiation, radiation safety, films and film processing, welding, casting and forging, aircraft structures and components, radiographic techniques, and records

  1. Safety analysis of control rod drive computers

    The analysis of the most significant user programmes revealed no errors in these programmes. The evaluation of approximately 82 cumulated years of operation demonstrated that the operating system of the control rod positioning processor has a reliability that is sufficiently good for the tasks this computer has to fulfil. Computers can be used for safety relevant tasks. The experience gained with the control rod positioning processor confirms that computers are not less reliable than conventional instrumentation and control system for comparable tasks. The examination and evaluation of computers for safety relevant tasks can be done with programme analysis or statistical evaluation of the operating experience. Programme analysis is recommended for seldom used and well structured programmes. For programmes with a long, cumulated operating time a statistical evaluation is more advisable. The effort for examination and evaluation is not greater than the corresponding effort for conventional instrumentation and control systems. This project has also revealed that, where it is technologically sensible, process controlling computers or microprocessors can be qualified for safety relevant tasks without undue effort. (orig./HP)

  2. Analysis of radial radiography for the liner stability series at Pegasus: PGII-59, PGII-62, and PGII-63

    Morgan, D.V.; Platts, D.; Shlachter, J.S.; Martinez, D.L.; Carpenter, B.

    1997-09-01

    Recently, three liner stability experiments were performed at the Pegasus II pulsed power facility to determine the asymmetric variations in the material density of a cylindrical liner during an electro-magnetically driven implosion. The initial campaign consisted of three experiments, designated LS-1, LS-2, and LS-3. LS-1 and LS-2 were driven with a peak current of approximately 4.2 MA, whereas the peak current for LS-3 was approximately 6.4 MA. All three liners initially were 0.4 mm wall aluminum cylinders with a mean radius of 2.38 cm and a height of 2.0 cm. The inner surface of each liner was coated with a thin (18--23 {micro}m) layer of gold to aid in the determination of the position of the inner surface of the liner. Radial radiography was used to characterize the z-dependent and {theta}-dependent instabilities that were observed as the liner contracted.

  3. Computation of Regularized Linear Discriminant Analysis

    Kalina, Jan; Valenta, Zdeněk; Duintjer Tebbens, Jurjen

    ISI, 2014. s. 8-8. [COMPSTAT 2014. International Conference on Computational Statistics /21./. 19.08.2014-22.08.2014, Geneva] Institutional support: RVO:67985807 Keywords : classification analysis * regularization * Matrix decomposition * shrinkage eigenvalues * high-dimensional data Subject RIV: BB - Applied Statistics, Operational Research

  4. Computation for the analysis of designed experiments

    Heiberger, Richard

    2015-01-01

    Addresses the statistical, mathematical, and computational aspects of the construction of packages and analysis of variance (ANOVA) programs. Includes a disk at the back of the book that contains all program codes in four languages, APL, BASIC, C, and FORTRAN. Presents illustrations of the dual space geometry for all designs, including confounded designs.

  5. Validity of compton radiography in soft tissue imaging

    The Compton radiography was shown to be capable of delineating subcutaneous and hepatic inflammations as well as normal muscles and fatty tissues with positive tomoimages. This is an noteworthy feature in contrast to the ordinary x-ray radiography. Computer assistance would probably cultivate its various clinical applicability. Radiological diagnosis of soft tissue morbidities can possibly be assisted to an appreciable degree by this technique. (author)

  6. Risk analysis enhancement via computer applications

    Since the development of Reliability Centered Maintenance (RCM) by the airline industry, there has been various alternative approaches to applying this methodology to the nuclear power industry. Some of the alternatives were developed in order to shift the focus of analyses on plant specific concerns but the greatest majority of alternatives were developed in attempt to reduce the effort required to conduct a RCM analysis on as large of scale as a nuclear power station. Computer applications have not only reduced the amount of analysis time but have also produced more consistent results, provided an effective working RCM analysis tool and made it possible to automate a Living Program. During the development of a RCM Program at South Carolina Electric and Gas' V.C. Summer Nuclear Station (VCSNS), computer applications were developed. 6 figs, 1 tab

  7. Comparison of conventional radiography and MDCT in suspected scaphoid fractures

    Cyrus; Behzadi; Murat; Karul; Frank; Oliver; Henes; Azien; Laqmani; Philipp; Catala-Lehnen; Wolfgang; Lehmann; Hans-Dieter; Nagel; Gerhard; Adam; Marc; Regier

    2015-01-01

    AIM: To determine the diagnostic accuracy and radiation dose of conventional radiography and multidetector computed tomography(MDCT) in suspected scaphoid fractures.METHODS: One hundred twenty-four consecutive patients were enrolled in our study who had suffered from a wrist trauma and showed typical clinical symptoms suspicious of an acute scaphoid fracture. All patients had initially undergone conventional radiography. Subsequent MDCT was performed within 10 d because of persisting clinical symptoms. Using the MDCT data as the reference standard, a fourfold table was used to classify the test results. The effective dose and impaired energy were assessed in order to compare the radiation burden of the two techniques. The Wilcoxon test was performed to compare the two diagnostic modalities.RESULTS: Conventional radiography showed 34 acute fractures of the scaphoid in 124 patients(42.2%). Subsequent MDCT revealed a total of 42 scaphoid fractures. The sensitivity of conventional radiography for scaphoid fracture detection was 42.8% and its specificity was 80% resulting in an overall accuracy of 59.6%. Conventional radiography was significantly inferior to MDCT(P < 0.01) concerning scaphoidfracture detection. The mean effective dose of MDCT was 0.1 m Sv compared to 0.002 m Sv of conventional radiography.CONCLUSION: Conventional radiography is insufficient for accurate scaphoid fracture detection. Regarding the almost negligible effective dose, MDCT should serve as the first imaging modality in wrist trauma.

  8. Quantitative analysis by in situ synchrotron X-ray radiography of the evolution of the mushy zone in a fixed temperature gradient

    Salloum-Abou-Jaoude, G.; Reinhart, G.; Combeau, H.; Založnik, M.; Lafford, T. A.; Nguyen-Thi, H.

    2015-02-01

    This paper deals with a series of experiments dedicated to the analysis of the time evolution of a mushy zone in a fixed temperature gradient, carried out on the BM05 beamline at the European Synchrotron Radiation Facility (ESRF) on Al-Cu alloy. Because most of phenomena involved in this evolution are dynamic, in situ and real time investigation is essential for conducting a thorough analysis as a function of time. Synchrotron X-ray radiography is a non-invasive visualization technique, perfectly suited to such a study since it is able to reveal the microstructural changes of the mushy zone during the holding stage. In addition, we extended our analysis by performing advanced image processing of synchrotron X-ray radiographs to characterize the solute distribution in the liquid phase. These measurements gave us crucial information for understanding the competition between the diffusion processes in the bulk and the mushy zone. Moreover, combining these data with mass balance equations at the two boundaries of the mushy zone enables us to demonstrate the major role of solute diffusion in the dynamics of the mushy zone, from the early instants to the final state of the holding stage.

  9. Codesign Analysis of a Computer Graphics Application

    Madsen, Jan; Brage, Jens P.

    1996-01-01

    This paper describes a codesign case study where a computer graphics application is examined with the intention to speed up its execution. The application is specified as a C program, and is characterized by the lack of a simple compute-intensive kernel. The hardware/software partitioning is based...... on information obtained from software profiling and the resulting design is validated through cosimulation. The achieved speed-up is estimated based on an analysis of profiling information from different sets of input data and various architectural options....

  10. Computation system for nuclear reactor core analysis

    This report documents a system which contains computer codes as modules developed to evaluate nuclear reactor core performance. The diffusion theory approximation to neutron transport may be applied with the VENTURE code treating up to three dimensions. The effect of exposure may be determined with the BURNER code, allowing depletion calculations to be made. The features and requirements of the system are discussed and aspects common to the computational modules, but the latter are documented elsewhere. User input data requirements, data file management, control, and the modules which perform general functions are described. Continuing development and implementation effort is enhancing the analysis capability available locally and to other installations from remote terminals

  11. Codesign Analysis of a Computer Graphics Application

    Madsen, Jan; Brage, Jens P.

    This paper describes a codesign case study where a computer graphics application is examined with the intention to speed up its execution. The application is specified as a C program, and is characterized by the lack of a simple compute-intensive kernel. The hardware/software partitioning is based...... on information obtained from software profiling and the resulting design is validated through cosimulation. The achieved speed-up is estimated based on an analysis of profiling information from different sets of input data and various architectural options....

  12. Computer-aided power systems analysis

    Kusic, George

    2008-01-01

    Computer applications yield more insight into system behavior than is possible by using hand calculations on system elements. Computer-Aided Power Systems Analysis: Second Edition is a state-of-the-art presentation of basic principles and software for power systems in steady-state operation. Originally published in 1985, this revised edition explores power systems from the point of view of the central control facility. It covers the elements of transmission networks, bus reference frame, network fault and contingency calculations, power flow on transmission networks, generator base power setti

  13. “Drug mules” as a radiological challenge: Sensitivity and specificity in identifying internal cocaine in body packers, body pushers and body stuffers by computed tomography, plain radiography and Lodox

    Purpose: The purpose of our study was to retrospectively evaluate the specificity, sensitivity and accuracy of computed tomography (CT), digital radiography (DR) and low-dose linear slit digital radiography (LSDR, Lodox®) in the detection of internal cocaine containers. Methods: Institutional review board approval was obtained. The study collectively consisted of 83 patients (76 males, 7 females, 16–45 years) suspected of having incorporated cocaine drug containers. All underwent radiological imaging; a total of 135 exams were performed: nCT = 35, nDR = 70, nLSDR = 30. An overall calculation of all “drug mules” and a specific evaluation of body packers, pushers and stuffers were performed. The gold standard was stool examination in a dedicated holding cell equipped with a drug toilet. Results: There were 54 drug mules identified in this study. CT of all drug carriers showed the highest diagnostic accuracy 97.1%, sensitivity 100% and specificity 94.1%. DR in all cases was 71.4% accurate, 58.3% sensitive and 85.3% specific. LSDR of all patients with internal cocaine was 60% accurate, 57.9% sensitive and 63.4% specific. Conclusions: CT was the most accurate test studied. Therefore, the detection of internal cocaine drug packs should be performed by CT, rather than by conventional X-ray, in order to apply the most sensitive exam in the medico-legal investigation of suspected drug carriers. Nevertheless, the higher radiation applied by CT than by DR or LSDR needs to be considered. Future studies should include evaluation of low dose CT protocols in order to address germane issues and to reduce dosage

  14. “Drug mules” as a radiological challenge: Sensitivity and specificity in identifying internal cocaine in body packers, body pushers and body stuffers by computed tomography, plain radiography and Lodox

    Flach, Patricia M., E-mail: patricia.flach@irm.uzh.ch [Centre for Forensic Imaging and Virtopsy, Institute of Forensic Medicine, University of Bern, Buehlstrasse 20, 3012 Bern (Switzerland); Department of Neuroradiology, Inselspital Bern, University of Bern, 3010 Bern (Switzerland); Centre for Forensic Imaging and Virtopsy, Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190/52, 8057 Zurich (Switzerland); Department of Radiology, University Hospital USZ, University of Zurich, Raemistrasse 100, 8091 Zurich (Switzerland); Ross, Steffen G. [Centre for Forensic Imaging and Virtopsy, Institute of Forensic Medicine, University of Bern, Buehlstrasse 20, 3012 Bern (Switzerland); Ampanozi, Garyfalia; Ebert, Lars [Centre for Forensic Imaging and Virtopsy, Institute of Forensic Medicine, University of Bern, Buehlstrasse 20, 3012 Bern (Switzerland); Centre for Forensic Imaging and Virtopsy, Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190/52, 8057 Zurich (Switzerland); Germerott, Tanja; Hatch, Gary M. [Centre for Forensic Imaging and Virtopsy, Institute of Forensic Medicine, University of Bern, Buehlstrasse 20, 3012 Bern (Switzerland); Thali, Michael J. [Centre for Forensic Imaging and Virtopsy, Institute of Forensic Medicine, University of Bern, Buehlstrasse 20, 3012 Bern (Switzerland); Centre for Forensic Imaging and Virtopsy, Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190/52, 8057 Zurich (Switzerland); Patak, Michael A. [Department of Radiology, Inselspital Bern, University of Bern, 3010 Bern (Switzerland); Department of Radiology, University Hospital USZ, University of Zurich, Raemistrasse 100, 8091 Zurich (Switzerland)

    2012-10-15

    Purpose: The purpose of our study was to retrospectively evaluate the specificity, sensitivity and accuracy of computed tomography (CT), digital radiography (DR) and low-dose linear slit digital radiography (LSDR, Lodox{sup ®}) in the detection of internal cocaine containers. Methods: Institutional review board approval was obtained. The study collectively consisted of 83 patients (76 males, 7 females, 16–45 years) suspected of having incorporated cocaine drug containers. All underwent radiological imaging; a total of 135 exams were performed: nCT = 35, nDR = 70, nLSDR = 30. An overall calculation of all “drug mules” and a specific evaluation of body packers, pushers and stuffers were performed. The gold standard was stool examination in a dedicated holding cell equipped with a drug toilet. Results: There were 54 drug mules identified in this study. CT of all drug carriers showed the highest diagnostic accuracy 97.1%, sensitivity 100% and specificity 94.1%. DR in all cases was 71.4% accurate, 58.3% sensitive and 85.3% specific. LSDR of all patients with internal cocaine was 60% accurate, 57.9% sensitive and 63.4% specific. Conclusions: CT was the most accurate test studied. Therefore, the detection of internal cocaine drug packs should be performed by CT, rather than by conventional X-ray, in order to apply the most sensitive exam in the medico-legal investigation of suspected drug carriers. Nevertheless, the higher radiation applied by CT than by DR or LSDR needs to be considered. Future studies should include evaluation of low dose CT protocols in order to address germane issues and to reduce dosage.

  15. Dual energy radiography using a single exposure technique

    This study presents preliminary results of single exposure dual energy computed radiography using laser stimulable luminescent phosphor imaging plate detectors. The single exposure technique makes use of four of these plates in a single cassette, each plate acting as an X-ray filter to the next so that the energy separation required for the dual energy basis decomposition is achieved. An analysis to determine the best operating technique for the chest is performed using computer simulation, and was found to be 85 kVp and 14 mAs. This information for the decomposition is obtained without additional dose to the patient. The ISo-transmission line technique is obtained without additional dose to the patient. The phantom was used to test the quality of the resulting calibration material equivalent images. The quality of the images, although slightly inferior to that of dual exposure techniques, seem acceptable for clinical application

  16. Quantitative film radiography

    We have developed a system of quantitative radiography in order to produce quantitative images displaying homogeneity of parts. The materials that we characterize are synthetic composites and may contain important subtle density variations not discernible by examining a raw film x-radiograph. In order to quantitatively interpret film radiographs, it is necessary to digitize, interpret, and display the images. Our integrated system of quantitative radiography displays accurate, high-resolution pseudo-color images in units of density. We characterize approximately 10,000 parts per year in hundreds of different configurations and compositions with this system. This report discusses: the method; film processor monitoring and control; verifying film and processor performance; and correction of scatter effects

  17. Digital radiography in space.

    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

  18. Probabilistic structural analysis computer code (NESSUS)

    Shiao, Michael C.

    1988-01-01

    Probabilistic structural analysis has been developed to analyze the effects of fluctuating loads, variable material properties, and uncertain analytical models especially for high performance structures such as SSME turbopump blades. The computer code NESSUS (Numerical Evaluation of Stochastic Structure Under Stress) was developed to serve as a primary computation tool for the characterization of the probabilistic structural response due to the stochastic environments by statistical description. The code consists of three major modules NESSUS/PRE, NESSUS/FEM, and NESSUS/FPI. NESSUS/PRE is a preprocessor which decomposes the spatially correlated random variables into a set of uncorrelated random variables using a modal analysis method. NESSUS/FEM is a finite element module which provides structural sensitivities to all the random variables considered. NESSUS/FPI is Fast Probability Integration method by which a cumulative distribution function or a probability density function is calculated.

  19. DC operating point analysis using evolutionary computing

    Crutchley, DA; Zwolinski, M.

    2004-01-01

    This paper discusses and evaluates a new approach to operating point analysis based on evolutionary computing (EC). EC can find multiple solutions to a problem by using a parallel search through a population. At the operating point(s) of a circuit the overall error has a minimum value. Therefore, we use an Evolutionary Algorithm (EA) to search the solution space to find these minima. Various evolutionary algorithms are described. Several such algorithms have been implemented in a full circuit...

  20. Constancy tests radiography X-ray devices with CR system

    The paper presents the changes in QAP (Quality Assurance Program) as consequence of digitalisation of medical facilities. Digitalisation brings many advantages - more comfort for personal use, images are easy achievable and transferable to workstation, fine quality images by postprocessing are easily achievable. But it must be taken into account that due to simplicity of image make it is sometimes taken more images then necessary .There are two possible ways of digitalisation in radiography: to exchange conventional developer machine by Computer Radiography (CR), that means to use CR reader and cassette with phosphor plate - un-direct digitalisation or to use special radiography X-ray devices with flat-panel detector -direct radiography. (authors)

  1. Computer analysis of HIV epitope sequences

    Gupta, G.; Myers, G.

    1990-01-01

    Phylogenetic tree analysis provide us with important general information regarding the extent and rate of HIV variation. Currently we are attempting to extend computer analysis and modeling to the V3 loop of the type 2 virus and its simian homologues, especially in light of the prominent role the latter will play in animal model studies. Moreover, it might be possible to attack the slightly similar V4 loop by this approach. However, the strategy relies very heavily upon natural'' information and constraints, thus there exist severe limitations upon the general applicability, in addition to uncertainties with regard to long-range residue interactions. 5 refs., 3 figs.

  2. First experience with digital radiography

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

  3. Euratom Neutron Radiography Working Group

    Domanus, Joseph Czeslaw

    1986-01-01

    In 1979 a Neutron Radiography Working Group (NRWG) was constituted within Buratom with the participation of all centers within the European Community at which neutron facilities were available. The main purpose of NRWG was to standardize methods and procedures used in neutron radiography of nuclear reactor fuel as well as establish standards for radiographic image quality of neutron radiographs. The NRWG meets once a year in each of the neutron radiography centers to review the progress made ...

  4. Digital radiography simulation for industrial applications with MCNPX

    Souza, Edmilson M. de; Correa, Samanda C.A.; Silva, Ademir X. da; Lopes, Ricardo T.; Oliveira, Davi F. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE)], E-mail: emonteiro@con.ufrj.br

    2007-07-01

    The energy dependent response of a BaFBr Image Plate detector was modeled and introduced in MCNPX radiography tally input. To convert MCNPX radiography tally output in 16 bits digital images, a post processing program called PROGRAMA IMAGEM is presented. Simulate images of a steel tube containing corrosion alveoli and grinded defects were compared with experimental images. The radiography technique used in all tests was double wall single image, DWSI, using an Iridium source ({sup 192}Ir) touching the adjacent wall. Visual and perfilometric analysis showed that the methodology used for sensible material simulation and data post-processing makes simulate digital images comparable to experimental images. (author)

  5. The Enhanced Workflow and Efficiency of the Wireless Local Area Network (WLAN)-Based Direct Digital Radiography (DDR) Portable Radiography.

    Ngan, Tsz-Lung; Wong, Edward Ting-Hei; Ng, Kris Lap-Shun; Jeor, Patrick Kwok-Shing; Lo, Gladys Goh

    2015-06-01

    With the implementation of the PACS in the hospital, there is an increasing demand from the clinicians for immediate access and display of radiological images. Recently, our hospital has installed the first wireless local area network (WLAN)-based direct digital radiography (DDR) portable radiography system. The DDR portable radiography system allows wireless retrieval of modality worklist and wireless transmission of portable X-ray image on the console to the Picture Archiving and Communication System (PACS), via WLAN connection of wireless fidelity (Wi-Fi). The aim of this study was to analyze the workflow and performance between the WLAN-based DDR portable radiography system and the old practice using conventional portable X-ray machine with computed radiography (CR) system. A total of 190 portable chest X-ray examinations were evaluated and timed, using the conventional portable X-ray machine with CR from March to April of 2012 and using the new DDR portable radiography system on December of 2012 (n = 97 for old system and n = 93 for DDR portable system). The time interval of image becoming available to the PACS using the WLAN-based DDR portable radiography system was significantly shorter than that of the old practice using the conventional portable X-ray machine with CR (6.8 ± 2.6 min for DDR portable system; 23 ± 10.2 min for old system; p WLAN-based DDR portable radiography system can enhance the workflow of portable radiography by reduction of procedural steps. PMID:25561071

  6. Quality assurance in digital radiography

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

  7. Quality assurance in digital radiography

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

  8. To Screen or not to Screen: Low Dose Computed Tomography in Comparison to Chest Radiography or Usual Care in Reducing Morbidity and Mortality from Lung Cancer.

    Dajac, Joshua; Kamdar, Jay; Moats, Austin; Nguyen, Brenda

    2016-01-01

    Lung cancer has the highest mortality rate of all cancers. This paper seeks to address the question: Can the mortality of lung cancer be decreased by screening with low-dose computerized tomography (LDCT) in higher risk patients compared to chest X-rays (CXR) or regular patient care? Currently, CXR screening is recommended for certain high-risk patients. Several recent trials have examined the effectiveness of LDCT versus chest radiography or usual care as a control. These trials include National Lung Screening Trial (NLST), Detection And screening of early lung cancer with Novel imaging TEchnology (DANTE), Lung Screening Study (LSS), Depiscan, Italian Lung (ITALUNG), and Dutch-Belgian Randomized Lung Cancer Screening Trial (Dutch acronym: NELSON study). NLST, the largest trial (n=53, 454), demonstrated a decrease in mortality from lung cancer in the LDCT group (RRR=20%, P=0.004). LSS demonstrated a greater sensitivity in detecting both early stage and any stage of lung cancer in comparison to traditional CXR. Although the DANTE trial yielded data consistent with findings in LSS, it also showed that via LDCT screening a greater proportion of patients were placed under unnecessary surgical procedures. The Depiscan trial yielded a high nodule detection rate at the cost of a high false-positive rate compared to CXR screening. The ITALUNG and NELSON trials demonstrated the early detection capabilities of LDCT for lung cancers compared to usual care without surveillance imaging. False-positive findings with unnecessary workup, intervention, and radiation exposure remain significant concerns for routine LDCT screening. However, current data suggests LDCT may provide a highly sensitive and specific means for detecting lung cancers and reducing mortality. PMID:27375974

  9. Boron determination in liver tissue by combining quantitative neutron capture radiography (QNCR) and histological analysis for BNCT treatment planning at the TRIGA Mainz.

    Schütz, C; Brochhausen, C; Altieri, S; Bartholomew, K; Bortolussi, S; Enzmann, F; Gabel, D; Hampel, G; Kirkpatrick, C J; Kratz, J V; Minouchehr, S; Schmidberger, H; Otto, G

    2011-09-01

    The typical primary malignancies of the liver are hepatocellular carcinoma and cholangiocarcinoma, whereas colorectal liver metastases are the most frequently occurring secondary tumors. In many cases, only palliative treatment is possible. Boron neutron capture therapy (BNCT) represents a technique that potentially destroys tumor tissue selectively by use of externally induced, locally confined secondary particle irradiation. In 2001 and 2003, BNCT was applied to two patients with colorectal liver metastases in Pavia, Italy. To scrutinize the rationale of BNCT, a clinical pilot study on patients with colorectal liver metastases was carried out at the University of Mainz. The distribution of the (10)B carrier (p-borono-phenylalanine) in the liver and its uptake in cancerous and tumor-free tissue were determined, focusing on a potential correlation between the uptake of p-borono-phenylalanine and the biological characteristics of cancerous tissue. Samples were analyzed using quantitative neutron capture radiography of cryosections combined with histological analysis. Methodological aspects of the combination of these techniques and results from four patients enrolled in the study are presented that indicate that the uptake of p-borono-phenylalanine strongly depends on the metabolic activity of cells. PMID:21692653

  10. Evaluation of knee-joint cartilage and menisci ten years after isolated and combined ruptures of the medial collateral ligament. Investigation by weight-bearing radiography, MR imaging and analysis of proteoglycan fragments in the joint fluid

    Purpose: To compare radiography, MR imaging, and chemical analysis in posttraumatic knees. Material and Methods: Ten matched pairs with either isolated partial rupture of the medial collateral ligament or combined medial collateral ligament/anterior cruciate ligament rupture were compared with matched controls 10 years after trauma. Weight-bearing radiographys and MR examinations were compared with proteoglycan fragment concentrations in the joint fluid. Results: The chemical analyses were similar in both trauma groups. The radiographs showed mild signs of arthrosis in half the patients with combined injury. MR images showed almost all injuried knees to have degenerative changes of various degrees in the cartilage and menisci. More frequent and more advanced changes were found after combined injury than after isolated injury (p<0.01). There were no changes in the controls. Conclusion: MR imaging is the best method for detecting and differentiating early posttraumatic knee arthrosis. (orig.)

  11. Evaluation of knee-joint cartilage and menisci ten years after isolated and combined ruptures of the medial collateral ligament. Investigation by weight-bearing radiography, MR imaging and analysis of proteoglycan fragments in the joint fluid

    Lundberg, M. [Univ. Hospital, Linkoeping (Sweden). Dept. of Orthopaedics and Sports Medicine (Sweden); Thuomas, K.Aa. [Univ. Hospital, Linkoeping (Sweden). Dept. of Diagnostic Radiology; Messner, K. [Univ. Hospital, Linkoeping (Sweden). Dept. of Orthopaedics and Sports Medicine (Sweden)

    1997-01-01

    Purpose: To compare radiography, MR imaging, and chemical analysis in posttraumatic knees. Material and Methods: Ten matched pairs with either isolated partial rupture of the medial collateral ligament or combined medial collateral ligament/anterior cruciate ligament rupture were compared with matched controls 10 years after trauma. Weight-bearing radiographys and MR examinations were compared with proteoglycan fragment concentrations in the joint fluid. Results: The chemical analyses were similar in both trauma groups. The radiographs showed mild signs of arthrosis in half the patients with combined injury. MR images showed almost all injuried knees to have degenerative changes of various degrees in the cartilage and menisci. More frequent and more advanced changes were found after combined injury than after isolated injury (p<0.01). There were no changes in the controls. Conclusion: MR imaging is the best method for detecting and differentiating early posttraumatic knee arthrosis. (orig.).

  12. Introduction to scientific computing and data analysis

    Holmes, Mark H

    2016-01-01

    This textbook provides and introduction to numerical computing and its applications in science and engineering. The topics covered include those usually found in an introductory course, as well as those that arise in data analysis. This includes optimization and regression based methods using a singular value decomposition. The emphasis is on problem solving, and there are numerous exercises throughout the text concerning applications in engineering and science. The essential role of the mathematical theory underlying the methods is also considered, both for understanding how the method works, as well as how the error in the computation depends on the method being used. The MATLAB codes used to produce most of the figures and data tables in the text are available on the author’s website and SpringerLink.

  13. Analysis of a Model for Computer Virus Transmission

    Peng Qin

    2015-01-01

    Computer viruses remain a significant threat to computer networks. In this paper, the incorporation of new computers to the network and the removing of old computers from the network are considered. Meanwhile, the computers are equipped with antivirus software on the computer network. The computer virus model is established. Through the analysis of the model, disease-free and endemic equilibrium points are calculated. The stability conditions of the equilibria are derived. To illustrate our t...

  14. Computation of Regularized Linear Discriminant Analysis

    Kalina, Jan; Valenta, Zdeněk; Duintjer Tebbens, Jurjen

    Geneva: Centre International de Conferences, 2014 - (Gilli, M.; Nieto-Reyes, A.; González-Rodríguez, G.), s. 1-8 ISBN 978-2-8399-1347-8. [COMPSTAT 2014. International Conference on Computational Statistics /21./. Geneva (CH), 19.08.2014-22.08.2014] R&D Projects: GA ČR GA13-06684S Institutional support: RVO:67985807 Keywords : classification analysis * regularization * Matrix decomposition * shrinkage eigenvalues * high-dimensional data Subject RIV: BB - Applied Statistics, Operational Research

  15. Computer modelling for LOCA analysis in PHWRs

    A computer code THYNAC developed for analysis of thermal hydraulic transient phenomena during LOCA in the PHWR type reactor and primary coolant system is described. The code predicts coolant voiding rate in the core, coolant discharge rate from the break, primary system depressurization history and temperature history of both fuel and fuel clad. Reactor system is modelled as a set of connected fluid segments which represent piping, feeders, coolant channels, etc. Method of finite difference is used in the code. Modelling of various specific phenomena e.g. two-phase pressure drop, slip flow, pumps etc. in the code is described. (M.G.B.)

  16. Progress in computer vision and image analysis

    Bunke, Horst; Sánchez, Gemma; Otazu, Xavier

    2009-01-01

    This book is a collection of scientific papers published during the last five years, showing a broad spectrum of actual research topics and techniques used to solve challenging problems in the areas of computer vision and image analysis. The book will appeal to researchers, technicians and graduate students. Sample Chapter(s). Chapter 1: An Appearance-Based Method for Parametric Video Registration (2,352 KB). Contents: An Appearance-Based Method for Parametric Video Registration (X Orriols et al.); Relevance of Multifractal Textures in Static Images (A Turiel); Potential Fields as an External

  17. FORTRAN computer program for seismic risk analysis

    McGuire, Robin K.

    1976-01-01

    A program for seismic risk analysis is described which combines generality of application, efficiency and accuracy of operation, and the advantage of small storage requirements. The theoretical basis for the program is first reviewed, and the computational algorithms used to apply this theory are described. The information required for running the program is listed. Published attenuation functions describing the variation with earthquake magnitude and distance of expected values for various ground motion parameters are summarized for reference by the program user. Finally, suggestions for use of the program are made, an example problem is described (along with example problem input and output) and the program is listed.

  18. Social sciences via network analysis and computation

    Kanduc, Tadej

    2015-01-01

    In recent years information and communication technologies have gained significant importance in the social sciences. Because there is such rapid growth of knowledge, methods and computer infrastructure, research can now seamlessly connect interdisciplinary fields such as business process management, data processing and mathematics. This study presents some of the latest results, practices and state-of-the-art approaches in network analysis, machine learning, data mining, data clustering and classifications in the contents of social sciences. It also covers various real-life examples such as t

  19. Microstructure and effective behavior - analysis and computation

    Material behavior is determined by features on a number of length scales between the atomistic and macroscopic scale. As full direct resolution of all scales is out of reach there is an intense research on analytical and computational tools that can bridge different scales and a number of different schemes have been proposed. One key issue is to identify which information on the finer scale is needed to determine the behavior on the coarser scale. To shed some light on this issue we will focus on number of case studies to understand the passage from macroscopic scales, where the material is described by a multi-well non-convex energy, to macroscopic behavior. Examples include shape-memory materials, new giant magnetostrictive materials and nematic elastomers. Similar ideas have been used by others and by us to understand dislocation arrangements, blistering of thin films and magnetic microstructures. We will discuss three algorithmic approaches to analyze effective behavior: purely analytical, hybrid analytical-computational and computation inspired by analysis. Refs. 5 (author)

  20. Computer network environment planning and analysis

    Dalphin, John F.

    1989-01-01

    The GSFC Computer Network Environment provides a broadband RF cable between campus buildings and ethernet spines in buildings for the interlinking of Local Area Networks (LANs). This system provides terminal and computer linkage among host and user systems thereby providing E-mail services, file exchange capability, and certain distributed computing opportunities. The Environment is designed to be transparent and supports multiple protocols. Networking at Goddard has a short history and has been under coordinated control of a Network Steering Committee for slightly more than two years; network growth has been rapid with more than 1500 nodes currently addressed and greater expansion expected. A new RF cable system with a different topology is being installed during summer 1989; consideration of a fiber optics system for the future will begin soon. Summmer study was directed toward Network Steering Committee operation and planning plus consideration of Center Network Environment analysis and modeling. Biweekly Steering Committee meetings were attended to learn the background of the network and the concerns of those managing it. Suggestions for historical data gathering have been made to support future planning and modeling. Data Systems Dynamic Simulator, a simulation package developed at NASA and maintained at GSFC was studied as a possible modeling tool for the network environment. A modeling concept based on a hierarchical model was hypothesized for further development. Such a model would allow input of newly updated parameters and would provide an estimation of the behavior of the network.

  1. Symbolic Computing in Probabilistic and Stochastic Analysis

    Kamiński Marcin

    2015-12-01

    Full Text Available The main aim is to present recent developments in applications of symbolic computing in probabilistic and stochastic analysis, and this is done using the example of the well-known MAPLE system. The key theoretical methods discussed are (i analytical derivations, (ii the classical Monte-Carlo simulation approach, (iii the stochastic perturbation technique, as well as (iv some semi-analytical approaches. It is demonstrated in particular how to engage the basic symbolic tools implemented in any system to derive the basic equations for the stochastic perturbation technique and how to make an efficient implementation of the semi-analytical methods using an automatic differentiation and integration provided by the computer algebra program itself. The second important illustration is probabilistic extension of the finite element and finite difference methods coded in MAPLE, showing how to solve boundary value problems with random parameters in the environment of symbolic computing. The response function method belongs to the third group, where interference of classical deterministic software with the non-linear fitting numerical techniques available in various symbolic environments is displayed. We recover in this context the probabilistic structural response in engineering systems and show how to solve partial differential equations including Gaussian randomness in their coefficients.

  2. Experimental analysis of computer system dependability

    Iyer, Ravishankar, K.; Tang, Dong

    1993-01-01

    This paper reviews an area which has evolved over the past 15 years: experimental analysis of computer system dependability. Methodologies and advances are discussed for three basic approaches used in the area: simulated fault injection, physical fault injection, and measurement-based analysis. The three approaches are suited, respectively, to dependability evaluation in the three phases of a system's life: design phase, prototype phase, and operational phase. Before the discussion of these phases, several statistical techniques used in the area are introduced. For each phase, a classification of research methods or study topics is outlined, followed by discussion of these methods or topics as well as representative studies. The statistical techniques introduced include the estimation of parameters and confidence intervals, probability distribution characterization, and several multivariate analysis methods. Importance sampling, a statistical technique used to accelerate Monte Carlo simulation, is also introduced. The discussion of simulated fault injection covers electrical-level, logic-level, and function-level fault injection methods as well as representative simulation environments such as FOCUS and DEPEND. The discussion of physical fault injection covers hardware, software, and radiation fault injection methods as well as several software and hybrid tools including FIAT, FERARI, HYBRID, and FINE. The discussion of measurement-based analysis covers measurement and data processing techniques, basic error characterization, dependency analysis, Markov reward modeling, software-dependability, and fault diagnosis. The discussion involves several important issues studies in the area, including fault models, fast simulation techniques, workload/failure dependency, correlated failures, and software fault tolerance.

  3. Computational methods for nuclear criticality safety analysis

    Nuclear criticality safety analyses require the utilization of methods which have been tested and verified against benchmarks results. In this work, criticality calculations based on the KENO-IV and MCNP codes are studied aiming the qualification of these methods at the IPEN-CNEN/SP and COPESP. The utilization of variance reduction techniques is important to reduce the computer execution time, and several of them are analysed. As practical example of the above methods, a criticality safety analysis for the storage tubes for irradiated fuel elements from the IEA-R1 research has been carried out. This analysis showed that the MCNP code is more adequate for problems with complex geometries, and the KENO-IV code shows conservative results when it is not used the generalized geometry option. (author)

  4. Proton radiography for clinical applications

    Talamonti, C., E-mail: cinzia.talamonti@unifi.i [Dipartimento di Fisiopatologia Clinica, Universita degli Studi di Firenze, v.le Morgagni 85, I-50134 Firenze (Italy); INFN, sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino (Italy); Azienda Ospedaliero-Universitaria Careggi, v.le Morgagni 85, I-50134 Firenze (Italy); Reggioli, V. [Dipartimento di Fisiopatologia Clinica, Universita degli Studi di Firenze, v.le Morgagni 85, I-50134 Firenze (Italy); Bruzzi, M. [INFN, sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino (Italy); Dipartimento di Energetica, Universita degli Studi di Firenze, via S. Marta 3, I-50139 Firenze (Italy); Bucciolini, M. [Dipartimento di Fisiopatologia Clinica, Universita degli Studi di Firenze, v.le Morgagni 85, I-50134 Firenze (Italy); INFN, sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino (Italy); Azienda Ospedaliero-Universitaria Careggi, v.le Morgagni 85, I-50134 Firenze (Italy); Civinini, C. [INFN, sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino (Italy); Marrazzo, L. [Azienda Ospedaliero-Universitaria Careggi, v.le Morgagni 85, I-50134 Firenze (Italy); Menichelli, D. [INFN, sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino (Finland) (Italy); Dipartimento di Energetica, Universita degli Studi di Firenze, via S. Marta 3, I-50139 Firenze (Italy); Pallotta, S. [Dipartimento di Fisiopatologia Clinica, Universita degli Studi di Firenze, v.le Morgagni 85, I-50134 Firenze (Italy); INFN, sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino (Italy); Azienda Ospedaliero-Universitaria Careggi, v.le Morgagni 85, I-50134 Firenze (Italy); Randazzo, N. [INFN, sezione di Catania, via S. Sofia 64, I-95123 Catania (Italy); Sipala, V. [INFN, sezione di Catania, via S. Sofia 64, I-95123 Catania (Italy); Dipartimento di Fisica, Universita degli Studi di Catania, via S. Sofia 64, I-95123 Catania (Italy)

    2010-01-11

    Proton imaging is not yet applied as a clinical routine, although its advantages have been demonstrated. In the context of quality assurance in proton therapy, proton images can be used to verify the correct positioning of the patient and to control the range of protons. Proton computed tomography (pCT) is a 3D imaging method appropriate for planning and verification of proton radiation treatments, because it allows evaluating the distributions of proton stopping power within the tissues and can be directly utilized when the patient is in the actual treatment position. The aim of the PRoton IMAging experiment, supported by INFN, and the PRIN 2006 project, supported by MIUR, is to realize a proton computed radiography (pCR) prototype for reconstruction of proton images from a single projection in order to validate the technique with pre-clinical studies and, eventually, to conceive the configuration of a complete pCT system. A preliminary experiment performed at the 250 MeV proton synchrotron of Loma Linda University Medical Center (LLUMC) allowed acquisition of experimental data before the completion of PRIMA project's prototype. In this paper, the results of the LLUMC experiment are reported and the reconstruction of proton images of two phantoms is discussed.

  5. Proton radiography for clinical applications

    Proton imaging is not yet applied as a clinical routine, although its advantages have been demonstrated. In the context of quality assurance in proton therapy, proton images can be used to verify the correct positioning of the patient and to control the range of protons. Proton computed tomography (pCT) is a 3D imaging method appropriate for planning and verification of proton radiation treatments, because it allows evaluating the distributions of proton stopping power within the tissues and can be directly utilized when the patient is in the actual treatment position. The aim of the PRoton IMAging experiment, supported by INFN, and the PRIN 2006 project, supported by MIUR, is to realize a proton computed radiography (pCR) prototype for reconstruction of proton images from a single projection in order to validate the technique with pre-clinical studies and, eventually, to conceive the configuration of a complete pCT system. A preliminary experiment performed at the 250 MeV proton synchrotron of Loma Linda University Medical Center (LLUMC) allowed acquisition of experimental data before the completion of PRIMA project's prototype. In this paper, the results of the LLUMC experiment are reported and the reconstruction of proton images of two phantoms is discussed.

  6. Good relationships between computational image analysis and radiological physics

    Good relationships between computational image analysis and radiological physics have been constructed for increasing the accuracy of medical diagnostic imaging and radiation therapy in radiological physics. Computational image analysis has been established based on applied mathematics, physics, and engineering. This review paper will introduce how computational image analysis is useful in radiation therapy with respect to radiological physics

  7. Good relationships between computational image analysis and radiological physics

    Arimura, Hidetaka; Kamezawa, Hidemi; Jin, Ze; Nakamoto, Takahiro; Soufi, Mazen

    2015-09-01

    Good relationships between computational image analysis and radiological physics have been constructed for increasing the accuracy of medical diagnostic imaging and radiation therapy in radiological physics. Computational image analysis has been established based on applied mathematics, physics, and engineering. This review paper will introduce how computational image analysis is useful in radiation therapy with respect to radiological physics.

  8. Good relationships between computational image analysis and radiological physics

    Arimura, Hidetaka, E-mail: arimurah@med.kyushu-u.ac.jp [Division of Medical Quantum Science, Department of Health Sciences, Faculty of Medical Sciences, Kyushu University (Japan); Kamezawa, Hidemi; Jin, Ze; Nakamoto, Takahiro; Soufi, Mazen [Division of Medical Quantum Science, Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University (Japan)

    2015-09-30

    Good relationships between computational image analysis and radiological physics have been constructed for increasing the accuracy of medical diagnostic imaging and radiation therapy in radiological physics. Computational image analysis has been established based on applied mathematics, physics, and engineering. This review paper will introduce how computational image analysis is useful in radiation therapy with respect to radiological physics.

  9. Detection of vertical root fractures of endodontically treated teeth by cone beam computed tomography versus digital radiography%锥形束CT诊断根管纵裂临床价值研究

    张海英; 闫波; 楚金普; 曹选平; 徐力; 姜文辉

    2013-01-01

    Objective To assess the diagnostic accuracy of cone beam computed tomography in comparison with digital radiography for detecting simulated complete vertical root fractures and imcomplete vertical root fractures in extracted hu-man teeth. Methods Sixty teeth were endodontically prepared and divided into 3 groups,2 experimental and 1 control. The teeth in experimental groups were artificially fractured and fixed together with 20 complete VRFs(group one)and 20 imcomplete VRFs(group two). Twenty teeth in control group were kept intact(group three). Three observers evaluat-ed the digital radiagraphs and CBCT images in terms of accuracy for VRFs detection. Results The overall accuracy for detecting VRFs was significantly higher for CBCT compared with the digital radiagraphs(P0.05). Conclusion The CBCT technique has higher accuracy than 2-D radiography for in vitro dignosis of VRFs;we can use CBCT to detect ear-ly VRFs.%目的:通过体外模型对比研究锥形束CT和根尖片对根管纵裂的诊断价值。方法收集2010-2011年郑州大学口腔医学院和肇庆市口腔医院因正畸或牙周病拔除的健康离体单根牙60颗,根管预备充填后,去除根充材料,再用根管钉用轻力使40颗牙根纵裂:20颗完全型牙根纵裂、20颗不完全型牙根纵裂;其余20颗完整牙根为对照。按正常牙位排列置于石膏模型上,分别用根尖片和锥形束CT扫描,阅片后作出诊断。结果根尖片与CBCT诊断根管纵裂的敏感度差异有统计学意义(P0.05)。结论 CBCT比根尖片诊断根管治疗后牙根纵裂的敏感度高,临床上可用CBCT辅助诊断早期牙根纵裂。

  10. 锥形束CT与根尖X线片对牙根纵裂诊断价值的对比研究%A comparison of cone-beam computed tomography with periapical radiography in detection of vertical root fracture

    薛媛; 倪龙兴; 王捍国; 郭翠红; 尤苏霞

    2011-01-01

    目的:对比研究牙科锥形束CT(CBCT)与普通根尖X线片在牙根纵裂诊断中的价值.方法:对2009-11--2010-10在我科经临床检查疑似牙根纵裂的69例病人(84个患牙)的根尖X线片及CBCT图像资料进行回顾性分析.由2位有经验的牙体牙髓科主治医生独立阅片,商讨达成一致后,与根尖切除、牙周翻瓣、拔除术等外科手术所见结果进行比较.并将CBCT与根尖X线片对牙根纵裂的诊断结果进行统计学分析.结果:CBCT诊断根裂的阳性检出率、灵敏度、准确度分别为82.1%、87.3%、88.1%,而根尖X线则为39.3%、41.8%、45.2%,差异有统计学意义(P<0.05).结论:CBCT与根尖X线片相比可更准确的诊断牙根纵裂,具有重要的临床应用价值.%AIM : To compare the diagnostic potential of cone-beam computed tomography ( CBCT) with conventional periapical radiography ( PR) for detecting vertical root fractures ( VRFs).METHODS: Sixty-nine patients with 84 teeth in which vertical root fracture was clinically suspected underwent periapical radiography and CBCT.Two experienced endodontists independendy analyzed each case and reached a consensus diagnosis.The results were compared with intraoperative fmdings and analyzed statistically.RESULTS : The positive rate, sensitivity and accuracy for VRFs of CBCT were 82.1%,87.3% and 88.10%, while the values of PRS were 39.3% , 41.8% and 45.2% , respectively( P <0.05).CONCLUSION: CBCT is supenor to periapical radioyaphy in the detection of vertical root fractures.

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

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

  12. ENDODONTIC MANAGEMENT OF A MAXILLARY FIRST MOLAR WITH FIVE CANALS WITH THE AID OF CONE BEAM COMPUTED RADIOGRAPHY: A CASE REPORT

    Paul Joseph

    2012-12-01

    Full Text Available This article presents a unique case of maxillary first molar with five canals. Cone beam computed tomography, as a complementary imaging device is used in confirming this unusual canal morphology and completing the endodontic treatment. This case report throws light into the possible variations in root canal anatomy and illustrates the use of imaging modalities like CBCT as a diagnostic adjunct.

  13. Computational analysis of PARAMETR facility experiments

    Full text of publication follows: Results of calculation of PARAMETR experiments are given in the paper. The PARAMETR facility is designed to research the phenomena relevant to typical LOCA scenarios (including severe accident) of VVER type reactors. The investigations at PARAMETR facility are directed to experimental research of fuel rods and core materials behavior, hydrogen generation processes, melting and interaction of core materials during severe accidents. The main facility components are rod bundle of 1250 mm heated length (up to 37 rods can be used), electrical power source, steam and water supply systems and instrumentation. The bundle is a mix of fresh fuel rods and electrically heated rods with uranium tablets and tungsten heater inside. The main objectives of calculations are analysis of computer code capability, in particular, RELAP/SCDAPSIM, to model severe accidents, identification of major parameter impact on calculation results and thus accident analysis improvements. RELAP/SCDAPSIM calculations were used to choose key parameters of experiments. Analysis of influence of thermal insulation properties, uncertainties of heater geometry, insulation thermal conductivity was done. Conditions and parameters needed to burn up intensive zirconium reaction were investigated. As a whole, calculation results showed good agreement with experiments. Some key points were observed such as essential impact of preheating phase, importance of thermal insulation material properties. Proper modeling of particular processes during preheating phase was very important since this phase defined bundle temperature level at the heating phase. There were some difficulties here. For instance, overestimation of temperatures had been observed until axial profiling of thermal conductivity was introduced. Some more proper models were used to reach the better agreement with experiments. The work done can be used in safety analysis of VVER type reactors and allow improving of

  14. Computer-aided Fault Tree Analysis

    A computer-oriented methodology for deriving minimal cut and path set families associated with arbitrary fault trees is discussed first. Then the use of the Fault Tree Analysis Program (FTAP), an extensive FORTRAN computer package that implements the methodology is described. An input fault tree to FTAP may specify the system state as any logical function of subsystem or component state variables or complements of these variables. When fault tree logical relations involve complements of state variables, the analyst may instruct FTAP to produce a family of prime implicants, a generalization of the minimal cut set concept. FTAP can also identify certain subsystems associated with the tree as system modules and provide a collection of minimal cut set families that essentially expresses the state of the system as a function of these module state variables. Another FTAP feature allows a subfamily to be obtained when the family of minimal cut sets or prime implicants is too large to be found in its entirety; this subfamily consists only of sets that are interesting to the analyst in a special sense

  15. Computed tomographic analysis of renal calculi

    Hillman, B.J.; Drach, G.W.; Tracey, P.; Gaines, J.A.

    1984-03-01

    An in vitro study sought to determine the feasibility of using computed tomography (CT) to analyze the chemical composition of renal calculi and thus aid in selecting the best treatment method. Sixty-three coded calculi were scanned in a water bath. Region-of-interest measurements provided the mean, standard deviation, and minimum and maximum pixel values for each stone. These parameters were correlated with aspects of the stones' chemical composition. A multivariate analysis showed that the mean and standard deviation of the stones' pixel values were the best CT parameters for differentiating types of renal calculi. By using computerized mapping techniques, uric acid calculi could be perfectly differentiated from struvite and calcium oxalate calculi. The latter two types also were differentiable, but to a lesser extent. CT has a potential role as an adjunct to clinical and laboratory methods for determining the chemical composition of renal calculi in an effort to select optimal treatment.

  16. Review of Computational Stirling Analysis Methods

    Dyson, Rodger W.; Wilson, Scott D.; Tew, Roy C.

    2004-01-01

    Nuclear thermal to electric power conversion carries the promise of longer duration missions and higher scientific data transmission rates back to Earth for both Mars rovers and deep space missions. A free-piston Stirling convertor is a candidate technology that is considered an efficient and reliable power conversion device for such purposes. While already very efficient, it is believed that better Stirling engines can be developed if the losses inherent its current designs could be better understood. However, they are difficult to instrument and so efforts are underway to simulate a complete Stirling engine numerically. This has only recently been attempted and a review of the methods leading up to and including such computational analysis is presented. And finally it is proposed that the quality and depth of Stirling loss understanding may be improved by utilizing the higher fidelity and efficiency of recently developed numerical methods. One such method, the Ultra HI-Fl technique is presented in detail.

  17. Computational Models for Analysis of Illicit Activities

    Nizamani, Sarwat

    devise policies to minimize them. These activities include cybercrimes, terrorist attacks or violent actions in response to certain world issues. Beside such activities, there are several other related activities worth analyzing, for which computational models have been presented in this thesis....... These models include a model for analyzing evolution of terrorist networks; a text classification model for detecting suspicious text and identification of suspected authors of anonymous emails; and a semantic analysis model for news reports, which may help analyze the illicit activities in certain area...... with location and temporal information. For the network evolution, the hierarchical agglomerative clustering approach has been applied to terrorist networks as case studies. The networks' evolutions show that how individual actors who are initially isolated from each other are converted in small groups, which...

  18. Computed tomographic analysis of renal calculi

    An in vitro study sought to determine the feasibility of using computed tomography (CT) to analyze the chemical composition of renal calculi and thus aid in selecting the best treatment method. Sixty-three coded calculi were scanned in a water bath. Region-of-interest measurements provided the mean, standard deviation, and minimum and maximum pixel values for each stone. These parameters were correlated with aspects of the stones' chemical composition. A multivariate analysis showed that the mean and standard deviation of the stones' pixel values were the best CT parameters for differentiating types of renal calculi. By using computerized mapping techniques, uric acid calculi could be perfectly differentiated from struvite and calcium oxalate calculi. The latter two types also were differentiable, but to a lesser extent. CT has a potential role as an adjunct to clinical and laboratory methods for determining the chemical composition of renal calculi in an effort to select optimal treatment

  19. Computational based functional analysis of Bacillus phytases.

    Verma, Anukriti; Singh, Vinay Kumar; Gaur, Smriti

    2016-02-01

    Phytase is an enzyme which catalyzes the total hydrolysis of phytate to less phosphorylated myo-inositol derivatives and inorganic phosphate and digests the undigestable phytate part present in seeds and grains and therefore provides digestible phosphorus, calcium and other mineral nutrients. Phytases are frequently added to the feed of monogastric animals so that bioavailability of phytic acid-bound phosphate increases, ultimately enhancing the nutritional value of diets. The Bacillus phytase is very suitable to be used in animal feed because of its optimum pH with excellent thermal stability. Present study is aimed to perform an in silico comparative characterization and functional analysis of phytases from Bacillus amyloliquefaciens to explore physico-chemical properties using various bio-computational tools. All proteins are acidic and thermostable and can be used as suitable candidates in the feed industry. PMID:26672917

  20. Interobserver reliability and intraobserver reproducibility of powers ratio for assessment of atlanto-occipital junction: comparison of plain radiography and computed tomography

    Li, Gang; Passias, Peter; Kozanek, Michal; Shannon, Brian D.; Li, Guoan; Villamil, Fernando; Bono, Christopher M.; Harris, Mitchel; Wood, Kirkham B.

    2009-01-01

    Powers ratio, as assessed on plain radiographs or computed tomography (CT) images, appears to have clinical and prognostic value. To date, the validation of this assessment tool has been limited to a small number of observers at a single site. No study has examined the intraobserver reproducibility and interobserver reliability of the Powers ratio measurement on plain radiographs or CT images among a large cohort of spine surgeons. This type of validation is critical to allow for the broader ...

  1. Radiation dose distribution monitoring at neutron radiography facility area, Nuclear Energy Unit, Malaysia

    One experiment was carried out to get the distribution of radiation doses at the neutron radiography facilities, Nuclear Energy Unit, Malaysia. The analysis was done to evaluate the safety level of the area. The analysis was used in neutron radiography work

  2. Resonance neutron radiography

    The production of images by the use of neutrons having energies in the resonance region is described. Two-dimensional position-sensitive neutron detectors are used to produce transmission images using neutron time-of-flight techniques at the National Bureau of Standards' electron linac facility. Two types of detectors are described. The first is a crossed-wire proportional counter using 3He as the neutron-sensitive component. The second type utilizes a multichannel plate electron multiplier and a resistive anode readout. A lithium glass scintillator is the neutron-sensitive component in the latter detector. Resonance neutron radiography, using these detectors, has the capability of producing images with isotopic and chemical element discrimination in a complex matrix with a resolution of 1 mm or better. (Auth.)

  3. Direct digital radiography versus conventional radiography for estimation of canal length in curved canals

    Mohtavipour, Seiedeh Tahereh; Dalili, Zahra; Azar, Nasim Gheshlaghi [Faculty of Dentistry, Guilan University of Medical Sciences, Guilan (Iran, Islamic Republic of)

    2011-03-15

    The purpose of this study was to compare the conventional and digital radiography in the estimation of working length in mandibular molars. Sixty molar teeth were selected and divided into three groups in the basis of canal curves (0-15 degree, 15-30 degree, >30 degree). After the placement of a 15 K-file, radiographs were taken with a conventional film (F-speed) and a digital sensor. Canal lengths were measured in these images by two observers. Statistical analysis was performed with repeated measures of ANOVA and paired sample t-test with 95% confidence. There was a high inter-observer agreement on the measurements of working length in conventional and digital radiographs. There was no significant difference between the mean values of measurements in conventional and digital radiography. Moreover, there was no significant difference between conventional and digital radiography with the actual values in the basis of canal curves. The accuracy of conventional and digital radiography in the determination of the working length was in an acceptable range.

  4. Direct digital radiography versus conventional radiography for estimation of canal length in curved canals

    The purpose of this study was to compare the conventional and digital radiography in the estimation of working length in mandibular molars. Sixty molar teeth were selected and divided into three groups in the basis of canal curves (0-15 degree, 15-30 degree, >30 degree). After the placement of a 15 K-file, radiographs were taken with a conventional film (F-speed) and a digital sensor. Canal lengths were measured in these images by two observers. Statistical analysis was performed with repeated measures of ANOVA and paired sample t-test with 95% confidence. There was a high inter-observer agreement on the measurements of working length in conventional and digital radiographs. There was no significant difference between the mean values of measurements in conventional and digital radiography. Moreover, there was no significant difference between conventional and digital radiography with the actual values in the basis of canal curves. The accuracy of conventional and digital radiography in the determination of the working length was in an acceptable range.

  5. IMAGING DIAGNOSIS--USE OF RADIOGRAPHY AND COMPUTED TOMOGRAPHY IN THE DIAGNOSIS OF A MINERALIZED YOLK SAC IN A BROWN KIWI (APTERYX MANTELLI).

    Wightman, Paul; Cohen, Eli B; Hunter, Stuart; Gartrell, Brett

    2015-01-01

    A 12-day-old Brown Kiwi (Apteryx mantelli) was presented with anorexia, torticollis, head-tilt, and coelomic distension. Radiographs showed an ill-defined, fat-opaque, coelomic mass displacing viscera craniodorsally. Curvilinear mineral opacities were superimposed over the ventral aspect of the mass. Computed tomography demonstrated the presence of mineral within the periphery of a fat attenuating mass consistent with a retained yolk sac. A deutectomy (yolk sac excision) was performed. Histopathology of the excised tissue confirmed the diagnosis of a retained yolk sac with multifocal mineralization. PMID:25199884

  6. Incremental ALARA cost/benefit computer analysis

    Commonwealth Edison Company has developed and is testing an enhanced Fortran Computer Program to be used for cost/benefit analysis of Radiation Reduction Projects at its six nuclear power facilities and Corporate Technical Support Groups. This paper describes a Macro-Diven IBM Mainframe Program comprised of two different types of analyses-an Abbreviated Program with fixed costs and base values, and an extended Engineering Version for a detailed, more through and time-consuming approach. The extended engineering version breaks radiation exposure costs down into two components-Health-Related Costs and Replacement Labor Costs. According to user input, the program automatically adjust these two cost components and applies the derivation to company economic analyses such as replacement power costs, carrying charges, debt interest, and capital investment cost. The results from one of more program runs using different parameters may be compared in order to determine the most appropriate ALARA dose reduction technique. Benefits of this particular cost / benefit analysis technique includes flexibility to accommodate a wide range of user data and pre-job preparation, as well as the use of proven and standardized company economic equations

  7. The Danube hospital project for automated transcription of X ray dose data from radiography, fluoroscopy and computed tomography (CT) into the electronic patient record

    Introduction: Assessment of X-ray exposure data is generally cumbersome, especially because of the lack of a commercially available solution for automatic integration of dose data into an electronic patient record (EPR). Therefore, we constructed a concept for automatically linking x-ray exposure data with a radiology information system (RIS). Material and Methods: X-ray modalities are equipped with a dose-area product (DAP) meter and connected to a RIS PC via a serial RS-232 interface. For computed tomography, dose-length product (DLP) is computed from the normalised CT dose index, number and thickness of slices. Examination details including number of frames, mAs, kV, exposure time etc. are recorded automatically by software polling and added to the examination record in the RIS. Results: The system has already been implemented with a digital fluororadiography system, other modalities are continuously being integrated. The time previously necessary for manual dose data transcription and saved now will sum up to about 1000 working hours per year. Conclusion: Automatic transfer of exposure parameters from X-ray imaging modalities to the EPR is important for quality assurance and risk assessment. Also, it facilitates compliance with legal requirements and set-up of diagnostic reference levels. (author)

  8. Performance Analysis of Cloud Computing Architectures Using Discrete Event Simulation

    Stocker, John C.; Golomb, Andrew M.

    2011-01-01

    Cloud computing offers the economic benefit of on-demand resource allocation to meet changing enterprise computing needs. However, the flexibility of cloud computing is disadvantaged when compared to traditional hosting in providing predictable application and service performance. Cloud computing relies on resource scheduling in a virtualized network-centric server environment, which makes static performance analysis infeasible. We developed a discrete event simulation model to evaluate the overall effectiveness of organizations in executing their workflow in traditional and cloud computing architectures. The two part model framework characterizes both the demand using a probability distribution for each type of service request as well as enterprise computing resource constraints. Our simulations provide quantitative analysis to design and provision computing architectures that maximize overall mission effectiveness. We share our analysis of key resource constraints in cloud computing architectures and findings on the appropriateness of cloud computing in various applications.

  9. Euratom neutron radiography working group

    In 1979 a Neutron Radiography Working Group (NRWG) was constituted within Euratom with the participation of all centers within the European Community at which neutron facilities were available. The main purpose of NRWG was to standardize methods and procedures used in neutron radiography of nuclear reactor fuel as well as establish standards for radiographic image quality of neutron radiographs. The NRWG meets once a year in each of the neutron radiography centers to review the progress made and draw plans for the future. Besides, ad-hoc sub-groups on different topics within the field of neutron radiography are constituted. This paper reviews the activities and achievements of the NRWG and its sub-groups. (author)

  10. Euratom Neutron Radiography Working Group

    Domanus, Joseph Czeslaw

    1986-01-01

    In 1979 a Neutron Radiography Working Group (NRWG) was constituted within Buratom with the participation of all centers within the European Community at which neutron facilities were available. The main purpose of NRWG was to standardize methods and procedures used in neutron radiography of nuclear...... reactor fuel as well as establish standards for radiographic image quality of neutron radiographs. The NRWG meets once a year in each of the neutron radiography centers to review the progress made and draw plans for the future. Besides, ad-hoc sub-groups or. different topics within the field of neutron...... radiography are constituted. This paper reviews the activities and achievements of the NRWG and its sub-groups....

  11. Computer Assisted Laboratory Instructions: Learning Outcomes Analysis

    Abdulrasool, Salah Mahdi; Mishra, Rakesh

    2006-01-01

    For this students in mechanical engineering subject area were exposed to computer assisted instructions to satisfy following learning outcomes in computer aided design/computer aided manufacturing module. i- Creation of drawing and design using Computer aided design ii- Using data exchange format (DXF) to create numerical control file iii- Final setup check of computerised numerical control machine iv- Final manufacturing of the product using CNC v- e ytilauQ valuation The t...

  12. The diagnosis of lameness associated with distal limb pathology in a horse: a comparison of radiography, computed tomography and magnetic resonance imaging

    A cadaver limb from an eight-year-old horse with right forelimb lameness that was relieved with an intra-articular distal interphalangeal joint block was imaged with radiographs, spiral computed tomography (CT) and magnetic resonance imaging (MRI). Spiral CT demonstrated several lucencies within the deep digital flexor tendon immediately proximal to the navicular bone. On MRI these areas had increased signal and there was enlargement of the tendon at this site. Effusion in the proximal interphalangeal joint and navicular bursa and thinning of the fibrocartilage of the navicular bone were also observed on MRI images. These changes were not detected on radiographs. Histopathology confirmed that there were focal areas of collagen necrosis within the deep digital flexor tendon with thinning and degenerative changes in the fibrocartilage of the navicular bone

  13. Beam characterization at the Neutron Radiography Reactor

    Highlights: • The project characterized the beam at the Neutron Radiography Reactor. • Experiments indicate that the neutron energy spectrum model may not be accurate. • The facility is a category I radiography facility. • The beam divergence and effective collimation ratio are 0.3 ± 0.1° and >125. • The predicted total neutron flux at the image plane is 5.54 × 106 n/cm2 s. -- Abstract: The quality of a neutron-imaging beam directly impacts the quality of radiographic images produced using that beam. Fully characterizing a neutron beam, including determination of the beam's effective length-to-diameter ratio, neutron flux profile, energy spectrum, potential image quality, and beam divergence, is vital for producing quality radiographic images. This paper provides a characterization of the east neutron imaging beamline at the Idaho National Laboratory Neutron Radiography Reactor (NRAD). The experiments which measured the beam's effective length-to-diameter ratio and potential image quality are based on American Society for Testing and Materials (ASTM) standards. An analysis of the image produced by a calibrated phantom measured the beam divergence. The energy spectrum measurements consist of a series of foil irradiations using a selection of activation foils, compared to the results produced by a Monte Carlo n-Particle (MCNP) model of the beamline. The NRAD has an effective collimation ratio greater than 125, a beam divergence of 0.3 ± 0.1°, and a gold foil cadmium ratio of 2.7. The flux profile has been quantified and the facility is an ASTM Category 1 radiographic facility. Based on bare and cadmium covered foil activation results, the neutron energy spectrum used in the current MCNP model of the radiography beamline over-samples the thermal region of the neutron energy spectrum

  14. Ferrofluids: Modeling, numerical analysis, and scientific computation

    Tomas, Ignacio

    This dissertation presents some developments in the Numerical Analysis of Partial Differential Equations (PDEs) describing the behavior of ferrofluids. The most widely accepted PDE model for ferrofluids is the Micropolar model proposed by R.E. Rosensweig. The Micropolar Navier-Stokes Equations (MNSE) is a subsystem of PDEs within the Rosensweig model. Being a simplified version of the much bigger system of PDEs proposed by Rosensweig, the MNSE are a natural starting point of this thesis. The MNSE couple linear velocity u, angular velocity w, and pressure p. We propose and analyze a first-order semi-implicit fully-discrete scheme for the MNSE, which decouples the computation of the linear and angular velocities, is unconditionally stable and delivers optimal convergence rates under assumptions analogous to those used for the Navier-Stokes equations. Moving onto the much more complex Rosensweig's model, we provide a definition (approximation) for the effective magnetizing field h, and explain the assumptions behind this definition. Unlike previous definitions available in the literature, this new definition is able to accommodate the effect of external magnetic fields. Using this definition we setup the system of PDEs coupling linear velocity u, pressure p, angular velocity w, magnetization m, and magnetic potential ϕ We show that this system is energy-stable and devise a numerical scheme that mimics the same stability property. We prove that solutions of the numerical scheme always exist and, under certain simplifying assumptions, that the discrete solutions converge. A notable outcome of the analysis of the numerical scheme for the Rosensweig's model is the choice of finite element spaces that allow the construction of an energy-stable scheme. Finally, with the lessons learned from Rosensweig's model, we develop a diffuse-interface model describing the behavior of two-phase ferrofluid flows and present an energy-stable numerical scheme for this model. For a

  15. Radiography and fluoroscopy, 1920 to the present.

    Krohmer, J S

    1989-11-01

    A survey of radiological procedures carried out in 1980 by J. L. Johnson and D. L. Abernathy indicated that of the 181 million procedures performed in that year, there were 77.5% plain radiographic studies, 12.7% contrast studies, 4.0% sonographic studies, 3.2% nuclear medicine studies, 1.8% CT studies and 0.8% special vascular procedures and cardiac catheterizations. Note that over 90% of all the studies were of the "conventional" type and that fewer than 2% were CT studies. In the early 70's when CT was introduced, it was predicted that it would soon take over most of radiography; some 7 or 8 years later, it was obvious that this would not take place. According to Tanako of the Fuji Photo Film Co. Ltd., conventional radiography has resisted being pushed aside because of its very high information content: 4-6 megabytes per image. A CT image contains about 0.5 megabytes. If a system is to take over from conventional radiography, it will have to overcome this large difference in information content. Digital or computed radiography seems capable of this, but probably not for some time (perhaps, 10 or 20 years). It seems unlikely that there will be much change, except for refinement, in the image intensified fluoroscopy equipment used for observing dynamic processes, and it will probably not be replaced. Another situation which will preclude the rapid demise of conventional radiography is financial inertia: There is between 5 and 10 billion dollars worth of diagnostic equipment in hospitals in this country and significant amount more in private offices and clinics. It is true that the amount has diminished in recent years, but this has been more because of DRG's than because of "takeover" by new modes of imaging. It is not likely that this investment will be given up quickly or easily. One must also keep in mind that the film digitization and the photostimulable phosphor digital systems, described above, do use existing radiographic equipment, and the image

  16. Research in applied mathematics, numerical analysis, and computer science

    1984-01-01

    Research conducted at the Institute for Computer Applications in Science and Engineering (ICASE) in applied mathematics, numerical analysis, and computer science is summarized and abstracts of published reports are presented. The major categories of the ICASE research program are: (1) numerical methods, with particular emphasis on the development and analysis of basic numerical algorithms; (2) control and parameter identification; (3) computational problems in engineering and the physical sciences, particularly fluid dynamics, acoustics, and structural analysis; and (4) computer systems and software, especially vector and parallel computers.

  17. Computational intelligence for big data analysis frontier advances and applications

    Dehuri, Satchidananda; Sanyal, Sugata

    2015-01-01

    The work presented in this book is a combination of theoretical advancements of big data analysis, cloud computing, and their potential applications in scientific computing. The theoretical advancements are supported with illustrative examples and its applications in handling real life problems. The applications are mostly undertaken from real life situations. The book discusses major issues pertaining to big data analysis using computational intelligence techniques and some issues of cloud computing. An elaborate bibliography is provided at the end of each chapter. The material in this book includes concepts, figures, graphs, and tables to guide researchers in the area of big data analysis and cloud computing.

  18. Numerical analysis of a neutron radiography-monitored infiltration experiment: Two-phase modeling using TOUGH2

    Princ, Tomas; Sacha, Jan; Snehota, Michal

    2015-04-01

    It has been shown in ponded infiltration-outflow column experiments that true steady state flow is often not reached in certain soils exhibiting preferential flow. Experiments often show a temporal change of flow rate that can, in the case of experiments conducted on saturated samples at constant head gradients, be interpreted as variations of saturated hydraulic conductivity. It has also been shown that these variations can be caused by slow redistribution of entrapped air in the sample. The experiment presented in this study was conducted on a small fabricated sample with axially symmetrical inner geometry of material distribution. In preparing the sample, areas of fine sand were surrounded by continuous preferential pathways composed of coarse sand. Ponded infiltration was performed on the sample while monitoring using neutron imaging was conducted to obtain spatiotemporal information about the water content distribution in the sample. Results of the experiment revealed that during the quasi-steady state stage of the experiment the saturated hydraulic conductivity gradually decreased due to the transfer of air bubbles from fine sand to coarse sand. Flow through the coarse sand became partially blocked by air bubbles and the overall quasi-steady flow rate consequently decreased by 30% during six hours of infiltration. In an attempt to model this behavior, we simulated ponded infiltration in two dimensional (2D) domains using the EOS3 module of the numerical simulator TOUGH2 (Lawrence Berkeley National Laboratory). The main objective was to determine which types of preferential pathway patterns were prone to air entrapment and whether the air redistribution observed in the experiment could be numerically simulated. Modeling was conducted in three different 2D domains with increasing complexity of the preferential pathways' geometry. Analysis of the results confirmed that during ponded infiltration, water percolated fastest at the start of infiltration through the

  19. Computational Analysis of Pharmacokinetic Behavior of Ampicillin

    Mária Ďurišová

    2016-07-01

    Full Text Available orrespondence: Institute of Experimental Pharmacology and Toxicology, Slovak Academy of Sciences, 841 04 Bratislava, Slovak Republic. Phone + 42-1254775928; Fax +421254775928; E-mail: maria.durisova@savba.sk 84 RESEARCH ARTICLE The objective of this study was to perform a computational analysis of the pharmacokinetic behavior of ampicillin, using data from the literature. A method based on the theory of dynamic systems was used for modeling purposes. The method used has been introduced to pharmacokinetics with the aim to contribute to the knowledge base in pharmacokinetics by including the modeling method which enables researchers to develop mathematical models of various pharmacokinetic processes in an identical way, using identical model structures. A few examples of a successful use of the modeling method considered here in pharmacokinetics can be found in full texts articles available free of charge at the website of the author, and in the example given in the this study. The modeling method employed in this study can be used to develop a mathematical model of the pharmacokinetic behavior of any drug, under the condition that the pharmacokinetic behavior of the drug under study can be at least partially approximated using linear models.

  20. Computational systems analysis of dopamine metabolism.

    Zhen Qi

    Full Text Available A prominent feature of Parkinson's disease (PD is the loss of dopamine in the striatum, and many therapeutic interventions for the disease are aimed at restoring dopamine signaling. Dopamine signaling includes the synthesis, storage, release, and recycling of dopamine in the presynaptic terminal and activation of pre- and post-synaptic receptors and various downstream signaling cascades. As an aid that might facilitate our understanding of dopamine dynamics in the pathogenesis and treatment in PD, we have begun to merge currently available information and expert knowledge regarding presynaptic dopamine homeostasis into a computational model, following the guidelines of biochemical systems theory. After subjecting our model to mathematical diagnosis and analysis, we made direct comparisons between model predictions and experimental observations and found that the model exhibited a high degree of predictive capacity with respect to genetic and pharmacological changes in gene expression or function. Our results suggest potential approaches to restoring the dopamine imbalance and the associated generation of oxidative stress. While the proposed model of dopamine metabolism is preliminary, future extensions and refinements may eventually serve as an in silico platform for prescreening potential therapeutics, identifying immediate side effects, screening for biomarkers, and assessing the impact of risk factors of the disease.

  1. [Computational genome analysis of three marine algoviruses].

    Stepanova, O A; Boĭko, A L; Shcherbatenko, I S

    2013-01-01

    Computational analysis of genomic sequences of three new marine algoviruses: Tetraselmis viridis virus (TvV-S20 and TvV-SI1 strains) and Dunaliella viridis virus (DvV-SI2 strain) was conducted. Both considerable similarity and essential distinctions between studied strains and the most studied marine algoviruses of Phycodnaviridae family were revealed. Our data show that the tested strains are new viruses with the following features: only they were isolated from marine eukaryotic microalgae T. viridis and D. viridis, coding sequences (CDSs) of their genomes are localized mainly on one of the DNA strands and form several clusters with short intergenic spaces; there are considerable variations in genome structure within viruses and their strains; viral genomic DNA has a high GC-content (55.5 - 67.4%); their genes contain no well-known optimal contexts of translation start codones, and the contexts of terminal codons read-through; the vast majority of viral genes and proteins do not have any matches in gene banks. PMID:24479317

  2. The CMS computing, software and analysis challenge

    The CMS experiment has performed a comprehensive challenge during May 2008 to test the full scope of offline data handling and analysis activities needed for data taking during the first few weeks of LHC collider operations. It constitutes the first full-scale challenge with large statistics under the conditions expected at the start-up of the LHC, including the expected initial mis-alignments and mis-calibrations for each sub-detector, and event signatures and rates typical for low instantaneous luminosity. Particular emphasis has been given to the prompt reconstruction workflows, and to the procedures for the alignment and calibration of each sub-detector. The latter were performed with restricted latency using the same computing infrastructure that will be used for real data, and the resulting calibration and alignment constants were used to re-reconstruct the data at Tier-1 centres. The paper addresses the goals and practical experience from the challenge, as well as the lessons learned in view of LHC data taking.

  3. Dual energy radiography using active detector technology

    A new technology has been implemented using an open-quotes active-detectorclose quotes comprised of two computed radiography (CR) imaging plates in a sandwich geometry for dual-energy radiography. This detector allows excellent energy separation, short exposure time, and high signal to noise ratio (SNR) for clinically robust open-quotes bone-onlyclose quotes and open-quotes soft-tissue onlyclose quotes images with minimum patient motion. Energy separation is achieved by two separate exposures at widely different kVp's: the high energy (120 kVp + 1.5 mm Cu filter) exposure is initiated first, followed by a short burst of intense light to erase the latent image on the front plate, and then a 50 kVp (low energy) exposure. A personal computer interfaced to the x-ray generator, filter wheel, and active detector system orchestrates the acquisition sequence within a time period of 150 msec. The front and back plates are processed using a CR readout algorithm with fixed speed and wide dynamic range. open-quotes Bone-onlyclose quotes and open-quotes soft-tissue onlyclose quotes images are calculated by geometric alignment of the two images and application of dual energy decomposition algorithms on a pixel by pixel basis. Resultant images of a calibration phantom demonstrate an increase of SNR2 / dose by ∼73 times when compared to a single exposure open-quotes passive-detectorclose quotes comprised of CR imaging plates, and an ∼8 fold increase compared to a screen-film dual-energy cassette comprised of different phosphor compounds. In conclusion, dual energy imaging with open-quotes active detectorclose quotes technology is clinically feasible and can provide substantial improvements over conventional methods for dual-energy radiography

  4. Assessing the use of digital radiography and a real-time interactive pulmonary nodule analysis system for large population lung cancer screening

    Rationale and objectives: To assess the use of chest digital radiograph (DR) assisted with a real-time interactive pulmonary nodule analysis system in large population lung cancer screening. Materials and methods: 346 DR/CR patient studies with corresponding CT images were selected from 12,500 patients screened for lung cancer from year 2007 to 2009. Two expert chest radiologists established CT-confirmed Gold Standard of nodules on DR/CR images with consensus. These cases were read by eight other chest radiologists (participating radiologists) first without using a real-time interactive pulmonary nodule analysis system and then re-read using the system. Performances of participating radiologists and the computer system were analyzed. Results: The computer system achieved similar performance on DR and CR images, with a detection rate of 76% and an average FPs of 2.0 per image. Before and after using the computer-aided detection system, the nodule detection sensitivities of the participating radiologists were 62.3% and 77.3% respectively, and the Az values increased from 0.794 to 0.831. Statistical analysis demonstrated statically significant improvement for the participating radiologists after using the computer analysis system with a P-value 0.05. Conclusion: The computer system could help radiologists identify more lesions, especially small ones that are more likely to be overlooked on chest DR/CR images, and could help reduce inter-observer diagnostic variations, while its FPs were easy to recognize and dismiss. It is suggested that DR/CR assisted by the real-time interactive pulmonary nodule analysis system may be an effective means to screen large populations for lung cancer.

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

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

  6. Angular signal radiography.

    Li, Panyun; Zhang, Kai; Bao, Yuan; Ren, Yuqi; Ju, Zaiqiang; Wang, Yan; He, Qili; Zhu, Zhongzhu; Huang, Wanxia; Yuan, Qingxi; Zhu, Peiping

    2016-03-21

    Microscopy techniques using visible photons, x-rays, neutrons, and electrons have made remarkable impact in many scientific disciplines. The microscopic data can often be expressed as the convolution of the spatial distribution of certain properties of the specimens and the inherent response function of the imaging system. The x-ray grating interferometer (XGI), which is sensitive to the deviation angle of the incoming x-rays, has attracted significant attention in the past years due to its capability in achieving x-ray phase contrast imaging with low brilliance source. However, the comprehensive and analytical theoretical framework is yet to be presented. Herein, we propose a theoretical framework termed angular signal radiography (ASR) to describe the imaging process of the XGI system in a classical, comprehensive and analytical manner. We demonstrated, by means of theoretical deduction and synchrotron based experiments, that the spatial distribution of specimens' physical properties, including absorption, refraction and scattering, can be extracted by ASR in XGI. Implementation of ASR in XGI offers advantages such as simplified phase retrieval algorithm, reduced overall radiation dose, and improved image acquisition speed. These advantages, as well as the limitations of the proposed method, are systematically investigated in this paper. PMID:27136780

  7. Contemporary practice education: Exploring student perceptions of an industrial radiography placement for final year diagnostic radiography students

    Introduction: There is a paucity of evidence in diagnostic radiography evaluating a career path into industrial imaging despite several higher education institutes stating this route as a career option on graduation. The link between a career in industrial radiography and diagnostic routes is unknown although there are anecdotal examples of individuals transferring between the two. Successfully obtaining a first post job following graduation in diagnostic radiography can be challenging in the current financial climate. A partnership was formed with an energy sector company that offered non-destructive testing/non-destructive evaluation (NDT/NDE) employing industrial radiographic technicians. Method: As an initial pilot, 5 (n = 5) final year diagnostic radiography students visited an industrial radiography site and underwent theoretical and practical training. Following this placement they engaged in a focus group and the student perceptions/responses were explored and recorded. Results: Common themes were identified and categorised via a thematic analysis. These were; radiation safety, physics and technology, widening access, graduate attributes/transferable skill sets and working conditions. Conclusion: Student discussion focussed around the benefits of working conditions in healthcare, the value of technology, safety and physics education in alternative placements and the transferability of skills into other/industrial sectors (e.g. NDT/NDE). Contemporary practice placements are a useful pedagogical approach to develop complex conceptual theoretical constructs, such as radiation physics. An in depth evaluation between the two industries skill sets is postulated. Additionally, this could offer alternative/emerging roles to interested diagnostic radiographers potentially meeting the skill shortage in industrial radiography. - Highlights: • Research in this area is novel. No evidence could be found to evaluate the links. • Students had theoretical

  8. Simplified computer codes for cask impact analysis

    In regard to the evaluation of the acceleration and deformation of casks, the simplified computer codes make analyses economical and decrease input and calculation time. The results obtained by the simplified computer codes have enough adequacy for their practical use. (J.P.N.)

  9. An Analysis of 27 Years of Research into Computer Education Published in Australian Educational Computing

    Zagami, Jason

    2015-01-01

    Analysis of three decades of publications in Australian Educational Computing (AEC) provides insight into the historical trends in Australian educational computing, highlighting an emphasis on pedagogy, comparatively few articles on educational technologies, and strong research topic alignment with similar international journals. Analysis confirms…

  10. Computational Intelligence in Intelligent Data Analysis

    Nürnberger, Andreas

    2013-01-01

    Complex systems and their phenomena are ubiquitous as they can be found in biology, finance, the humanities, management sciences, medicine, physics and similar fields. For many problems in these fields, there are no conventional ways to mathematically or analytically solve them completely at low cost. On the other hand, nature already solved many optimization problems efficiently. Computational intelligence attempts to mimic nature-inspired problem-solving strategies and methods. These strategies can be used to study, model and analyze complex systems such that it becomes feasible to handle them. Key areas of computational intelligence are artificial neural networks, evolutionary computation and fuzzy systems. As only a few researchers in that field, Rudolf Kruse has contributed in many important ways to the understanding, modeling and application of computational intelligence methods. On occasion of his 60th birthday, a collection of original papers of leading researchers in the field of computational intell...

  11. Transonic wing analysis using advanced computational methods

    Henne, P. A.; Hicks, R. M.

    1978-01-01

    This paper discusses the application of three-dimensional computational transonic flow methods to several different types of transport wing designs. The purpose of these applications is to evaluate the basic accuracy and limitations associated with such numerical methods. The use of such computational methods for practical engineering problems can only be justified after favorable evaluations are completed. The paper summarizes a study of both the small-disturbance and the full potential technique for computing three-dimensional transonic flows. Computed three-dimensional results are compared to both experimental measurements and theoretical results. Comparisons are made not only of pressure distributions but also of lift and drag forces. Transonic drag rise characteristics are compared. Three-dimensional pressure distributions and aerodynamic forces, computed from the full potential solution, compare reasonably well with experimental results for a wide range of configurations and flow conditions.

  12. High speed motion neutron radiography of two-phase flow

    Current research in the area of two-phase flow utilizes a wide variety of sensing devices, but some limitations exist on the information which can be obtained. Neutron radiography is a feasible alternative to ''see'' the two-phase flow. A system to perform neutron radiographic analysis of dynamic events which occur on the order of several milliseconds has been developed at Oregon State University. Two different methods have been used to radiograph the simulated two-phase flow. These are pulsed, or ''flash'' radiography, and high speed movie neutron radiography. The pulsed method serves as a ''snap-shot'' with an exposure time ranging from 10 to 20 milliseconds. In high speed movie radiography, a scintillator is used to convert neutrons into light which is enhanced by an optical intensifier and then photographed by a high speed camera. Both types of radiography utilize the pulsing capability of the OSU TRIGA reactor. The principle difficulty with this type of neutron radiography is the fogging of the image due to the large amount of scattering in the water. This difficulty can be overcome by using thin regions for the two-phase flow or using heavy water instead of light water. The results obtained in this paper demonstrate the feasibility of using neutron radiography to obtain data in two-phase flow situations. Both movies and flash radiographs have been obtained of air bubbles in water and boiling from a heater element. The neutron radiographs of the boiling element show both nucleate boiling and film boiling. (Auth.)

  13. Introduction to numerical analysis and scientific computing

    Nassif, Nabil

    2013-01-01

    Computer Number Systems and Floating Point Arithmetic Introduction Conversion from Base 10 to Base 2Conversion from Base 2 to Base 10Normalized Floating Point SystemsFloating Point OperationsComputing in a Floating Point SystemFinding Roots of Real Single-Valued Functions Introduction How to Locate the Roots of a Function The Bisection Method Newton's Method The Secant MethodSolving Systems of Linear Equations by Gaussian Elimination Mathematical Preliminaries Computer Storage for Matrices. Data Structures Back Substitution for Upper Triangular Systems Gauss Reduction LU DecompositionPolynomia

  14. Performance Analysis of Various New Technologies for Computing

    M Nagaraju; Anitha, B

    2012-01-01

    The discipline of computing is the systematic study of algorithmicprocesses that describe and transform information along with their theory, analysis, design, efficiency, implementation, and application. Application software, also known as an "application" or an "app", iscomputer softwaredesigned to help the user to perform specific tasks. Recent interests and demand in computing made new technologies to emerge in which cloud computing is the one. Cloud Computing has become another buzzword a...

  15. A Comparative Analysis of Computer Literacy Education for Nurses

    Hardin, Richard C.; Skiba, Diane J.

    1982-01-01

    Despite recent advances by nursing in the computer field computer literacy is a rarity among nursing professionals. Our analysis of existing educational models in nursing (baccalaureate, staff development, continuing education, and vendor) shows that no single educational strategy is likely to be effective in achieving computer literacy for all nurses. A refinement of the computer literacy concept is proposed which divides the educational needs of nurses into specific objectives based on desi...

  16. Modern Computational Techniques for the HMMER Sequence Analysis

    Xiandong Meng; Yanqing Ji

    2013-01-01

    This paper focuses on the latest research and critical reviews on modern computing architectures, software and hardware accelerated algorithms for bioinformatics data analysis with an emphasis on one of the most important sequence analysis applications—hidden Markov models (HMM). We show the detailed performance comparison of sequence analysis tools on various computing platforms recently developed in the bioinformatics society. The characteristics of the sequence analysis, such as data and c...

  17. Computational Modeling, Formal Analysis, and Tools for Systems Biology

    Bartocci, Ezio; Lió, Pietro

    2016-01-01

    As the amount of biological data in the public domain grows, so does the range of modeling and analysis techniques employed in systems biology. In recent years, a number of theoretical computer science developments have enabled modeling methodology to keep pace. The growing interest in systems biology in executable models and their analysis has necessitated the borrowing of terms and methods from computer science, such as formal analysis, model checking, static analysis, and runtime verificat...

  18. ANACROM - A computer code for chromatogram analysis

    The computer code was developed for automatic research of peaks and evaluation of chromatogram parameters as : center, height, area, medium - height width (FWHM) and the rate FWHM/center of each peak. (Author)

  19. Behavior computing modeling, analysis, mining and decision

    2012-01-01

    Includes six case studies on behavior applications Presents new techniques for capturing behavior characteristics in social media First dedicated source of references for the theory and applications of behavior informatics and behavior computing

  20. Towed Water Turbine Computational Fluid Dynamics Analysis

    Maughan, Robert G.

    2013-01-01

    Computational fluid dynamics can be used to predict operating conditions of towed water turbines which are used in long distance sailing applications to meet electrical demands. The design consists of a turbine fastened to a shaft which is attached to a generator by a rope. The turbine is pulled in water behind a sailboat and torque is transmitted through the rope to turn the onboard generator and produce power. Torque curves from an alternator, generator, and from computational fluid dynamic...