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1

Computed radiography  

International Nuclear Information System (INIS)

In an effort to evaluate the feasibility of introducing computed radiography (FCR) into mass screening for lung cancer, the ability of FCR to detect nodules one cm in diameter was examined using a humanoid chest phantom. Based on the receiver operating characteristic (ROC) analysis, the detectability of FCR was compared with that of conventional radiography and photofluorography. The values of area under ROC curves were higher for FCR (0.963 for image similar to that with conventional film-intensifying screen system, image A; and 0.952 for processed image, image B) than the other two methods (0.774 for radiography and 0.789 for photofluorography). Degradation of image quality in FCR could be avoided by a wide latitude even if proper exposure techniques might not be employed. Images A and B in FCR yielded excellent delineation for nodules in the lung field and in the retrocardiac and subdiaphragmatic regions, respectively. This may have implications for the value of simultaneous interpretation of both images in increasing diagnostic accuracy. Structured noise of the ribs and blood vessels had scarcely an effect on nodule detectability in FCR. Radiation dose could be reduced to one third of the standard dose. It can thus be concluded that FCR is feasible in mass screening for lung cancer in terms of increased diagnostic ability and low radiation doses. (Namekawa, K.)

2

Scale analysis using X-ray microfluorescence and computed radiography  

Science.gov (United States)

Scale deposits are the most common and most troublesome damage problems in the oil field and can occur in both production and injection wells. They occur because the minerals in produced water exceed their saturation limit as temperatures and pressures change. Scale can vary in appearance from hard crystalline material to soft, friable material and the deposits can contain other minerals and impurities such as paraffin, salt and iron. In severe conditions, scale creates a significant restriction, or even a plug, in the production tubing. This study was conducted to qualify the elements present in scale samples and quantify the thickness of the scale layer using synchrotron radiation micro-X-ray fluorescence (SR?XRF) and computed radiography (CR) techniques. The SR?XRF results showed that the elements found in the scale samples were strontium, barium, calcium, chromium, sulfur and iron. The CR analysis showed that the thickness of the scale layer was identified and quantified with accuracy. These results can help in the decision making about removing the deposited scale.

Candeias, J. P.; de Oliveira, D. F.; dos Anjos, M. J.; Lopes, R. T.

2014-02-01

3

Gastrointestinal radiography using Fuji computed radiography (FCR)  

International Nuclear Information System (INIS)

Initial clinical experience in gastrointestinal radiography using Fuji Computed Radiography(FCR) system was reported. Image quality of conventional film/screen radiography and FCR system on upper GI series and barium enema was compared. Reflecting wide dynamic range of the system, improved image quality was confirmed, particularity in visibility of fine mucosal pattern(area gastricae), folds and overall contour. High sensor sensitivity of the system could reduce radiation dose requirement significantly. Diagnostically acceptable images were obtained with approximately 1/5 of routine dose for conventional radiography except in cases of lateral view of the rectum. (author)

4

Computed radiography acceptance testing  

Science.gov (United States)

Compact sized computed radiography (CR) systems based on photostimulable phosphor technology are now being more widely used in radiology departments. Measurement of imaging performance at time of installation is essential to ensure that the CR system is operating within the manufacturer's specifications and producing a clinically acceptable image quality. At any given radiation dose, CR imaging performance primarily relates to image contrast, spatial resolution, and noise. Tests for these key aspects of CR performance are described and typical results, as obtained with a commercial system, are presented.

Huda, Walter; Arreola, Manuel; Jing, Zhenxue

1995-05-01

5

New computed radiography technologies for digital radiography  

International Nuclear Information System (INIS)

Digital radiography (DR) has become integral to modern diagnostic radiology. One of the earliest forms of DR, computed radiography (CR) using storage phosphors, has established itself as the mainstay of DR-based diagnostic imaging over the past 20 years. More recently, flat-panel DR systems based on solid state X-ray detectors with integrated, large-area, active-matrix readout electronics are promising further improvements in clinical workflow and image quality. Despite CR's longevity, innovations continue to be made.New developments in CR screen technologies, like structured (needle) screens, and new scanner concepts based on line-at-a-time reading promise major improvements in image quality (comparable to that of flat-panel systems), system through-put and physical size, at a cost comparable to that of today's systems. Thus, despite the advent of flat-panel acquisition systems, there will still be an important role for CR in the foreseeable future.After a brief review of the current state of CR technology, this paper will explore several of these new CR developments and present some examples of their potential clinical impact. (orig.)

6

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

International Nuclear Information System (INIS)

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 ?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 ?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)

7

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

8

Computed radiography in NDT applications  

International Nuclear Information System (INIS)

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 themaphy, and what the major benefits for them have been. (author)

9

Computed radiography in NDT application  

International Nuclear Information System (INIS)

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.

10

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

International Nuclear Information System (INIS)

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)

11

Comparison of radiographic texture analysis from computed radiography and bone densitometry systems.  

Science.gov (United States)

Osteoporosis is a disease that results in an increased risk of bone fracture due to a loss of bone mass and deterioration of bone structure. Bone mineral density (BMD) provides a measure of bone mass and is frequently measured by bone densitometry systems to diagnose osteoporosis. In addition, computerized radiographic texture analysis (RTA) is currently being investigated as a measure of bone structure and as an additional diagnostic predictor of osteoporosis. In this study, we assessed the ability of a peripheral bone densitometry (PD) system to yield images useful for RTA. The benefit of such a system is that it measures BMD by dual-energy x-ray absorptiometry and therefore provides high- and low-energy digital radiographic images. The bone densitometry system investigated was the GE/Lunar PIXI, which provides 512 x 512 digital images of the heel or forearm (0.2 mm pixels). We compared texture features of heel images obtained with this PD system to those obtained on a Fuji computed radiography (CR) system (0.1 mm pixels). Fourier and fractal-based texture features of images from 24 subjects who had both CR and BMD exams were calculated, and correlation between the two systems was analyzed. Fourier-based texture features characterize the magnitude, frequency content, and orientation of the trabecular bone pattern. Good correlation was found between the two modalities for the first moment (FMP) with r=0.71 (p value0.05), while the standard deviation of the RMS did correlate with r=0.79 (p valuefractal-based texture features with r=0.79 (p valuemethod. The PD system therefore may have the potential for yielding heel images suitable for RTA. PMID:15125006

Wilkie, Joel R; Giger, Maryellen L; Chinander, Michael R; Vokes, Tamara J; Li, Hui; Dixon, Larry; Jaros, Vit

2004-04-01

12

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

International Nuclear Information System (INIS)

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

Application of computed radiography to ERCP  

International Nuclear Information System (INIS)

Computed radiography technic was applied to ERCP. Fuji Computed Radiography System was used. The pancreatogram obtained by this method was compared with that of conventional screen-film radiograph. The much finer changes of the pancreatogram can be delineated by the new method. The diagnostic ability of ERCP is thus enhanced by the introduction of FCR. (author)

14

Computed radiography systems performance evaluation  

International Nuclear Information System (INIS)

The performance of a computed radiography system was evaluated, according to the AAPM Report No. 93. Evaluation tests proposed by the publication were performed, and the following nonconformities were found: imaging p/ate (lP) dark noise, which compromises the clinical image acquired using the IP; exposure indicator uncalibrated, which can cause underexposure to the IP; nonlinearity of the system response, which causes overexposure; resolution limit under the declared by the manufacturer and erasure thoroughness uncalibrated, impairing structures visualization; Moire pattern visualized at the grid response, and IP Throughput over the specified by the manufacturer. These non-conformities indicate that digital imaging systems' lack of calibration can cause an increase in dose in order that image prob/ems can be so/ved. (author)

15

Physical and psychophysical analysis of laser readout conditions for imaging plates in computed radiography  

International Nuclear Information System (INIS)

This paper reports on computed radiography that uses a photostimulable phosphor coated imaging plate which is exposed to x-rays and laser read to form an image. After laser reading, there is a considerable amount of energy remaining on the imaging plate which is not used. This study simulated a change in the laser readout process to utilize more of the energy on the image plate, and potentially improve image quality without changing exposure factors. Images of a contrast detail phantom were made before and after alteration of the readout process and analyzed by both physical and psychophysical means. It was found that there is an increase in the signal-to-noise ratio, when measured with an aperture of the size of a single pixel (linear dimension about 0.15 mm). However there is no change in the signal-to-noise ratio, when measured with apertures of the size of 0.75 mm (5 x 5 pixels) and 1.5 mm (10 x 10 pixels). This agrees with the results of the contrast detail study: after alteration, the observers did not detect smaller objects than they had before the alteration. It appears the imaging plate readout process is fairly optimized

16

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

Energy Technology Data Exchange (ETDEWEB)

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.)

Gruber, Michael; Uffmann, Martin; Weber, Michael; Balassy, Csilla; Schaefer-Prokop, Cornelia [Medical University of Vienna, Department of Radiology and Ludwig Boltzmann-Institute for Clinical and Experimental Radiologic Research, Vienna (Austria); Prokop, Mathias [University Medical Center, Department of Radiology, Utrecht (Netherlands)

2006-07-15

17

Computed multiple-beam equalization radiography  

International Nuclear Information System (INIS)

Multiple-beam equalization radiography (MBER) minimizes the problem of various body thicknesses as well as large variations of tissue density in projectional radiography. Computed radiography (CR) with a reusable laser-stimulated luminescent phosphor image plate allows a very large dynamic range of exposure as well as a digital image processing technique for image enhancement. Combination of the MBER and CR technologies can potentially improve the diagnostic value of projection radiography. An Amber advanced multiple-beam equalization radiography system and a FCR/SP901 CR system were used for this study. X-ray exposures of step wedges, line pair phantoms, anthropomorphic chest phantom, and volunteers were taken with the Amber, first with the film/screen cassette and then with the CR imaging plate. Two comparisons were made: analog Amber film versus CR film and digitized Amber film versus CR Amber images displayed on 2K video monitors

18

Analysis of a high-resolution computed radiography imaging plate versus conventional screen-film radiography for neonatal intensive care unit applications  

Science.gov (United States)

The image quality of a special high-resolution computed radiography (CR) imaging plate is compared with that of conventional screen-film radiography via measurements of physical factors related to the signal and noise of each detector system. Physical parameters reflecting image contrast, spatial resolution and signal-to-noise characteristics are measured as a function of radiation dose for each detector configuration. Standard signal detector configurations for the acquisition of plain film and CR images are compared with those from a modified film cassette containing both a CR plate and conventional screen-film for a dual-image recording technique. The modified dual detector film cassette configuration allows for a single-exposure, simultaneous acquisition of images for the direct clinical comparison of conventional screen- film and CR radiographs. The small physical size of the newborn chest and the types of lung processes that must be evaluated in the critical care neonate present a particular challenge to the spatial resolution limitations of CR. The clinical utility of the special high-resolution CR plate is assessed for such neonatal intensive care unit applications.

Andriole, Katherine P.; Gooding, Charles A.; Gould, Robert G.; Huang, H. K.

1994-05-01

19

Acceptance testing of Computed Radiography systems  

International Nuclear Information System (INIS)

Acceptance testing of computed radiography systems (CR) is required to verify not only image quality but also compliance with the manufacturer's specifications. Therefore, CR acceptance testing is manufacturer-specific. This paper describes a series of performance tests performed on a large number of CRs (FCR 5000, Fuji) recently acquired by our institution. In particular, we describe the following tests: dark noise, uniformity, exposure calibration, linearity and auto ranging, limiting resolution, noise and low-contrast resolution, spatial accuracy, laser-beam function, erasure thoroughness, aliasing, grid response. Special attention is given to the practical aspects related to measurement and subsequent image analysis. We report the results obtained in the various tests. No significant variations from the reference levels were found. Nonetheless, in some cases the operating procedures had to be adapted

20

Autoradiographic analysis of radiolabeled anti-carcinoembryonic antigen monoclonal antibody CEA 102 in colorectal cancer using computed radiography  

International Nuclear Information System (INIS)

Anti-carcinoembryonic antigen monclonal antibody (MAb) CEA 102 was produced by immunization with purified CEA and the specific accumulation of radiolabeled CEA 102 in colorectal cancers was investigated by autoradiography of sugical specimens using Fuji Computed Radiography (FCR). Five patients with colorectal cancer were injected intravenously with 131I-labeled intact CEA 102 or its F(ab')2. Primary tumor and liver metastases were successfully detected by external scanning with a gamma camera in 4 cases. Autoradiographic study of the surgical specimens using FCR showed predominant localization of 131I-labeled CEA 102 in primary tumors and liver metastases in all cases. Even a small liver metastasis (0.5 cm) was clearly visualized in the autoradiogram by FCR. The pixel distribution curves of the density of the respective tissues in the autoradiograms by FCR showed the heterogeneity of the distribution of administreted radiolabeled MAb in individual tumors, but the density of the tumors was higher than the normal tissues. In the quantitative distribution analysis of CEF 102, the uptake of the primary tumor (mean 1.10% ID/kg) was ten-fold greater than that of the normal colon mucosa (mean 0.10% ID/kg). These results revealed that the application of MAb has great potential in radioimmunodetection as well as in antibody-directed therapy. (auhtor)

 
 
 
 
21

Advanced multiple beam equalization radiography (AMBER) combined with computed radiography  

International Nuclear Information System (INIS)

The combined use of AMBER (Advanced Multiple Beam Equalization Radiography) and a digital storage phosphor (SP) radiography system was evaluated for chest radiography in a pilot study with 4 patients. Four image modes with different dose levels were compared: The SP in combination with an AMBER equalized exposure (SP/AMBER) and 3 nonequalized exposures with dose levels corresponding to the respective calculated AMBER lung dose (SP/lung field dose), the calculated AMBER mediastinal dose (SP/mediastinal dose) and the calculated AMBER average dose (SP/average dose). All image modes were matched for Hurter and Driffield characteristics and subjectively rated according to visibility of details. The improved signal-to-noise (S/N) ratio of SP/AMBER resulted in a better visualization of structures in the mediastinum and the basal lung where SP/lung field dose scored lowest. For the central lung no quality differences were seen between techniques. The compressed dynamic range of the SP/AMBER images was more easily displayed on the hard-copy film. The combination of AMBER with SP radiography promises to overcome the dynamic range limitations of digital displays while, at moderate doses, giving better S/N and image quality than standard SP technique. (orig.)

22

Computed radiography simulation using the Monte Carlo code MCNPX  

International Nuclear Information System (INIS)

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)

23

Radiological protection procedures for industrial applications of computed radiography  

International Nuclear Information System (INIS)

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)

24

Digital subtraction cerebral angiography using Fuji computed radiography  

International Nuclear Information System (INIS)

Our experience with digital subtraction cerebral angiography using Fuji computed radiography 101 is reported. A new system of Fuji computed radiography was used with an imaging plate instead of the conventional film. The image of the X-ray was analysed with the computer, subtracted, and printed on the film with this system. Serial cerebral angiography with Fuji computed radiography was performed by the transvenous injection of the contrast medium. Vessels in the neck were visualized well, but intracranial large vessels, while they were visualized, were not clear, and small vessels were not traceable. The direct cerebral or transbrachial angiography with Fuji computed radiography was performed using 20% Angiografin. The cerebral angiography using 20% Angiografin and the conventional cerebral angiography using 65% Angiografin provided similar angiographic information. Perforating arteries less than 0.2 mm in diameter could be resolved with Fuji computed radiography 101. (author)

25

Spectrum optimization for computed radiography systems  

Science.gov (United States)

Technical quality assurance (TQA) is one of the key issues in breast screening protocols where the two crucial aspects are image quality and dose. While digital radiography (DR) systems can produce excellent image quality at low dose, it appears often to be difficult with computed radiography (CR) systems to fulfill the requirements for image quality and to keep the dose below the limits. Here, the choice of the optimal spectrum can be necessary to comply with the limiting values given by the standards. To determine the optimal spectrum, we calculated the contrast-noise ratio (CNR) for different anode/filter (a/f) combinations in dependence of tube voltage. This was done for breast thicknesses of 50, 60 and 70 mm. The figure-of-merit to be optimized was the quotient of squared CNR and average glandular dose. The investigated imaging plates were made of BaFBrI:Eu from a Fuji CR system. For comparison we repeated the measurements on a Carestream system. With respect to the Fuji system we found that the two k-edges of Iodine at 33 kV and Barium at 37 kV influence the results significantly. A peak as found in DR systems is followed by two additional peaks resulting from the higher absorption at the k-edges. This can be experienced with all a/f combinations. The same effect also occurred on the Carestream system.

Hummel, Johann; Semturs, Friedrich; Kaar, Marcus; Homolka, Peter; Figl, Michael

2014-03-01

26

Physical aspects of photostimulable phosphor computed radiography.  

Science.gov (United States)

Currently photostimulable phosphor computed radiography (PPCR) promises to be the digital X-ray image acquisition technology of choice for classical radiography (i.e. X-ray examinations of natural anatomy). For the last two years we have been carrying out a physical evaluation of modern PPCR technology and some of our findings relevant to general radiographic applications are reviewed here. Topics covered include the function of the auto-reader system and the reliability of image reproduction, the radiation exposure requirement and physical image quality. The latter is based upon both objective and subjective measures of image quality. These studies have yielded a favourable comparison of the image quality of modern PPCR technology with that of medium-speed and fast radiographic screen-film combinations. The major advantages of PPCR appear to be the maintenance of high imaging efficiency (DQE) over a much wider range of signal levels than film and consistent image acquisition and presentation independent of exposure level. In general radiographic applications no major limitations due to the comparatively modest limiting spatial resolution of PPCR [maximum limiting resolution = 5 line-pair mm-1] have been experienced. Digital image enhancement is a central element of PPCR image reproduction. The authors believe that advances in image enhancement algorithms remain a potential area for further improving the presented quality of PPCR images. PMID:8495288

Cowen, A R; Workman, A; Price, J S

1993-04-01

27

Performance evaluation of a computed radiography system  

International Nuclear Information System (INIS)

Computed radiography (CR) standards have been formalized and published in Europe and in the US. The CR system classification is defined in those standards by - minimum normalized signal-to-noise ratio (SNRN), and - maximum basic spatial resolution (SRb). Both the signal-to-noise ratio (SNR) and the contrast sensitivity of a CR system depend on the dose (exposure time and conditions) at the detector. Because of their wide dynamic range, the same storage phosphor imaging plate can qualify for all six CR system classes. The exposure characteristics from 30 to 450 kV, the contrast sensitivity, and the spatial resolution of the KODAK INDUSTREX CR Digital System have been thoroughly evaluated. This paper will present some of the factors that determine the system's spatial resolution performance. (authors)

28

Computer radiography-X-ray with vision  

International Nuclear Information System (INIS)

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

29

Portable Digital Radiography and Computed Tomography Manual  

Energy Technology Data Exchange (ETDEWEB)

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

2007-11-01

30

Performance evaluation of computed radiography systems  

International Nuclear Information System (INIS)

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

31

Simulation of computed radiography with imaging plate detectors  

Science.gov (United States)

Computed radiography (CR) using phosphor imaging plate detectors is taking an increasing place in Radiography Testing. CR uses similar equipment as conventional radiography except that the classical X-ray film is replaced by a numerical detector, called image plate (IP), which is made of a photostimulable layer and which is read by a scanning device through photostimulated luminescence. Such digital radiography has already demonstrated important benefits in terms of exposure time, decrease of source energies and thus reduction of radioprotection area besides being a solution without effluents. This paper presents a model for the simulation of radiography with image plate detectors in CIVA together with examples of validation of the model. The study consists in a cross comparison between experimental and simulation results obtained on a step wedge with a classical X-ray tube. Results are proposed in particular with wire Image quality Indicator (IQI) and duplex IQI.

Tisseur, D.; Costin, M.; Mathy, F.; Schumm, A.

2014-02-01

32

Simulation of computed radiography with imaging plate detectors  

International Nuclear Information System (INIS)

Computed radiography (CR) using phosphor imaging plate detectors is taking an increasing place in Radiography Testing. CR uses similar equipment as conventional radiography except that the classical X-ray film is replaced by a numerical detector, called image plate (IP), which is made of a photostimulable layer and which is read by a scanning device through photostimulated luminescence. Such digital radiography has already demonstrated important benefits in terms of exposure time, decrease of source energies and thus reduction of radioprotection area besides being a solution without effluents. This paper presents a model for the simulation of radiography with image plate detectors in CIVA together with examples of validation of the model. The study consists in a cross comparison between experimental and simulation results obtained on a step wedge with a classical X-ray tube. Results are proposed in particular with wire Image quality Indicator (IQI) and duplex IQI

33

Simulation of computed radiography with imaging plate detectors  

Energy Technology Data Exchange (ETDEWEB)

Computed radiography (CR) using phosphor imaging plate detectors is taking an increasing place in Radiography Testing. CR uses similar equipment as conventional radiography except that the classical X-ray film is replaced by a numerical detector, called image plate (IP), which is made of a photostimulable layer and which is read by a scanning device through photostimulated luminescence. Such digital radiography has already demonstrated important benefits in terms of exposure time, decrease of source energies and thus reduction of radioprotection area besides being a solution without effluents. This paper presents a model for the simulation of radiography with image plate detectors in CIVA together with examples of validation of the model. The study consists in a cross comparison between experimental and simulation results obtained on a step wedge with a classical X-ray tube. Results are proposed in particular with wire Image quality Indicator (IQI) and duplex IQI.

Tisseur, D.; Costin, M. [CEA LIST, CEA Saclay 91191 Gif sur Yvette Cedex (France); Mathy, F. [CEA-LETI, Campus Minatec, F-38054, Grenoble (France); Schumm, A. [EDF R and D, 1 avenue du général de gaulle 92141 Clamart (France)

2014-02-18

34

A methodology for radiological accidents analysis in industrial gamma radiography  

International Nuclear Information System (INIS)

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)

35

Radiography  

Science.gov (United States)

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

Gardner, C. G.

1973-01-01

36

Detection of intracardiac calcification using Fuji computed radiography  

International Nuclear Information System (INIS)

Fuji Computed Radiography (FCR) was evaluated for detection of intracardiac calcification as compared with conventional radiography in 77 patients. Intracardiac calcification was found in 37 patients (left coronary artery: 31, right coronary artery: 11, valve: 9) on cine-fluorography. The sensitivity for detecting these calcified foci with FCR was higher than conventional screen-film method. Especially, sensitivity for detecting left coronary artery calcification with FCR was significantly higher than conventional method (71 %, 32 %) (p < 0.01), Fine anatomical details of calcification were well shown on FCR. Chest radiography using FCR is of great use for detection of intracardiac calcification. (author)

37

Collaboration in radiography: A bibliometric analysis  

International Nuclear Information System (INIS)

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.

38

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

International Nuclear Information System (INIS)

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, opening them

39

Clinical Evaluation of a Dual-Side Readout Technique Computed Radiography System in Chest Radiography of Premature Neonates  

International Nuclear Information System (INIS)

Background: Recently, the dual-side readout technique has been introduced in computed radiography, leading to an increase in detective quantum efficiency (DQE) compared with the single-side readout technique. Purpose: To evaluate if the increase in DQE with the dual-side readout technique results in a higher clinical image quality in chest radiography of premature neonates at no increase in radiation dose. Material and Methods: Twenty-four chest radiographs of premature neonates were collected from both a single-side readout technique system and a double-side readout technique system. The images were processed in the same image-processing station in order for the comparison to be only dependent on the difference in readout technique. Five radiologists rated the fulfillment of four image quality criteria, which were based on important anatomical landmarks. The given ratings were analyzed using visual grading characteristics (VGC) analysis. Results: The VGC analysis showed that the reproduction of the carina with the main bronchi and the thoracic vertebrae behind the heart was better with the dual-side readout technique, whereas no significant difference for the reproduction of the central vessels or the peripheral vessels could be observed. Conclusions: The results indicate that the higher DQE of the dual-side readout technique leads to higher clinical image quality in chest radiography of premature neonates at no increase in radiation dose. Keywords: Digital radiograpadiation dose. Keywords: Digital radiography; lung; observer performance; pediatrics; thorax

40

Computer-aided diagnosis in chest radiography  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Chest radiographs account for more than half of all radiological examinations; the chest is the ?mirror of health and disease?. This thesis is about techniques for computer analysis of chest radiographs. It describes methods for texture analysis and segmenting the lung fields and rib cage in a chest film. It includes a description of an automatic system for detecting regions with abnormal texture, that is applied to a database of images from a tuberculosis screening ...

Ginneken, B.

2001-01-01

 
 
 
 
41

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  

Energy Technology Data Exchange (ETDEWEB)

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)

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

42

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

International Nuclear Information System (INIS)

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)

43

Digital radiography; A useful clinical tool for computer-aided diagnosis by quantitative analysis of radiographic images  

Energy Technology Data Exchange (ETDEWEB)

In this review, we present the current results of our schemes for computerized automated analysis that are being developed at the University of Chicago for (1) the identification of lung nodules, the assessment of interstitial disease and cardiomegaly in chest radiographs; (2) the identification of clustered microcalcifications and masses in mammography; and (3) the assessment of stenotic lesions in angiograms. (orig./MG).

Doi, K. (Department of Radiology, Kurt Rossman Laboratories for Radiologic Image Research, University of Chicago, IL (United States)); Giger, M.L. (Department of Radiology, Kurt Rossman Laboratories for Radiologic Image Research, University of Chicago, IL (United States)); Nishikawa, R.M. (Department of Radiology, Kurt Rossman Laboratories for Radiologic Image Research, University of Chicago, IL (United States)); Hoffmann, K.R. (Department of Radiology, Kurt Rossman Laboratories for Radiologic Image Research, University of Chicago, IL (United States)); MacMahon, H. (Department of Radiology, Kurt Rossman Laboratories for Radiologic Image Research, University of Chicago, IL (United States)); Schmidt, R.A. (Department of Radiology, Kurt Rossman Laboratories for Radiologic Image Research, University of Chicago, IL (United States)); Chua, K.G. (Department of Radiology, Kurt Rossman Laboratories for Radiologic Image Research, University of Chicago, IL (United States))

1993-09-01

44

Computed radiography dose optimization in pediatric patients  

International Nuclear Information System (INIS)

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)

45

Computed radiography dose optimization in pediatric patients  

International Nuclear Information System (INIS)

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)

46

Evaluation of the chest radiography using Fuji computed radiography (FCR) system  

International Nuclear Information System (INIS)

Chest radiograms obtained by using Fuji Computed Radiography (FCR) system were compared to conventional film/screen radiograms. The FCR images showed better image quality in diagnostic information than the conventional chest images. In FCR, the radiation exposure to patient for chest examination could be reduced up to one tenths of conventional chest examination. The main advantages or FCR were considered to depend on the contrast processing and frequency processing properties. The use of FCR in clinical work may improve both diagnostic quality and radiation exposure

47

Practical guidelines for radiographers to improve computed radiography image quality  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Computed Radiography (CR) has become a major digital imaging modality in a modern radiological department. CR system changes workflow from the conventional way of using film/screen by employing photostimulable phosphor plate technology. This results in the changing perspectives of technical, artefacts and quality control issues in radiology departments. Guidelines for better image quality in digital medical enterprise include professional guidelines for users and the quality control programme...

Pongnapang, N.

2005-01-01

48

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  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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 4 [...] 8 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. Abstract in english 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 diagnosi [...] s of squamous cell carcinoma in different sites of the maxillofacial region. Panoramic radiographs and computed tomographs were obtained at the University of Iowa Hospitals and Clinics, at FUNDECTO - USP and at the hospital of the University of São Paulo (USP). We observed a considerable limitation of the panoramic radiography in determining the localization and extension of tumors, since it revealed unclear delimitations. Regarding CT, better results were obtained: it was possible to observe the invasion of the tumor toward adjacent soft tissues, as well as the extension of bone destruction and the depth of the lesion, which were confirmed by surgical findings. We concluded that computed tomography demonstrated to be a sensitive radiographic technique for the detection of the involvement of bone and soft tissues, contributing for a more precise diagnosis, surgical planning and intervention. On the other hand, panoramic radiography was considered less sensitive and less efficient than CT, since it shows only unclear borders of the lesions and is not able to assess the involvement of soft tissues.

Amanda Cáceres, PEREIRA; Marcelo de Gusmão Paraiso, CAVALCANTI; Patrícia dos Santos, TOSSATO; Fábio José, GUIDA; Maria Cecília Andrea, DUAIK; Márcia, KUROISHI.

49

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  

Directory of Open Access Journals (Sweden)

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 tomographs were obtained at the University of Iowa Hospitals and Clinics, at FUNDECTO - USP and at the hospital of the University of São Paulo (USP. We observed a considerable limitation of the panoramic radiography in determining the localization and extension of tumors, since it revealed unclear delimitations. Regarding CT, better results were obtained: it was possible to observe the invasion of the tumor toward adjacent soft tissues, as well as the extension of bone destruction and the depth of the lesion, which were confirmed by surgical findings. We concluded that computed tomography demonstrated to be a sensitive radiographic technique for the detection of the involvement of bone and soft tissues, contributing for a more precise diagnosis, surgical planning and intervention. On the other hand, panoramic radiography was considered less sensitive and less efficient than CT, since it shows only unclear borders of the lesions and is not able to assess the involvement of soft tissues.

Amanda Cáceres PEREIRA

2001-12-01

50

Computer-aided recognition of emphysema on digital chest radiography  

International Nuclear Information System (INIS)

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.

51

The Evaluation of Overexposure Effect on Computed Radiography  

International Nuclear Information System (INIS)

This research was accomplished to assess image quality changes with reduced and increased dose in chest computed radiography (CR), ultimately to find the minimum dose that provides necessary resolution requested by the clinical chest diagnosis and reduced radiation exposure to a patient. Most of the radiological diagnoses especially for abdominal and head diagnosis are currently dependant on computed tomography (CT) because that CT is superior to general radiography (GR). CT provides sectional sliced view and 3-D anatomy with high resolution. Nevertheless of the advantages of the CT many of the chest diagnoses including basic preoperative diagnostic procedures, for example, a tubercle diagnosis are still in reliance upon general radiography. Film imaging system has been used for GR, but recent years computed radiography (CR) is substituting for film imaging system because that CR is cheap in long term carrying charge, make it easy to store images at a small data storage device instead of large film storage room, and is suitable to picture archiving and communication system (PACS). When the CR was first introduced to the clinic it was announced that CR could reduce radiation exposure to the patient with many other benefits, but recent studies show that CR causes over exposure to the patient than traditional film-screen system. In contrast to the film-screen system, because that the over exposure in CR increases signal to noise ratio (SNR) which is result in the better image quality, the radiological technician is tend to over exposure in clinical radiology. It causes different effect in film-screen system, because the over exposure or under exposure makes the film over developed or under developed which is result in unreadable image

52

Computer-aided diagnosis in chest radiography: Beyond nodules  

International Nuclear Information System (INIS)

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.

53

Computer-aided diagnosis in chest radiography: Beyond nodules  

Energy Technology Data Exchange (ETDEWEB)

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.

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

54

Computer-aided diagnosis in chest radiography  

International Nuclear Information System (INIS)

Automating mass chest screening for tuberculosis (TB) requires segmentation and texture analysis in chest radiographs. Several rule-based schemes, pixel classifiers, and active shape model techniques for segmenting lung fields in chest radiographs are described and compared. An improved version of the active shape model segmentation technique, originally developed by Cootes and Taylor from Manchester University, UK, is described that uses optimal local features to steer the segmentation process and outperforms the original method in segmentation tasks for several types of medical images: chest radiographs and slices from MRI brain data. In order to segment the posterior ribs in PA chest radiographs, a statistical model of the complete rib cage is constructed using principal components analysis and a method is described to fit this model to input images automatically. For texture analysis, an extension is proposed to the framework of locally orderless images, a multiscale description of local histograms recently proposed by Koenderink and Van Doorn from Utrecht University, The Netherlands. The segmentation and texture analysis techniques are combined into a single method that automatically detects textural abnormalities in chest radiographs and estimates the probability that an image contains abnormalities. The method was evaluated on two databases. On a 200 case database of clinical chest films with interstitial disease from the University of Chicago, excellent results are obtained (area under the ROC curve Az=0.986). The results for a 600 case database from a TB screening program are encouraging (area under the ROC curve Az=0.820)

55

Computed radiography for characterisation of the weight-bearing knee  

International Nuclear Information System (INIS)

Purpose: A new method for examining and measuring the weight-bearing knee in computed radiography (CR) and picture archiving and communication systems (PACS) has recently been developed on examination equipment used in QUESTOR Precision Radiography (QPR). QPR is a method for the standardised examination of the knee, and generates 9 angles (e.g. hip-knee-ankle (HKA) angle) and 10 distances, corrected for parallax and magnification. The aim of this present study was to evaluate the reproducibility of this newly developed method and to determine intra- and inter-observer variation in its measurements. Material and Methods: The images were generated on a CR system, archived, and transferred to a multimodality work-station that had a monitor with a resolution of 1280x1024 (1 kx1 k). Photostimulable phosphor plates were used to generate images with a matrix of 1760x2140 pixels (pixel size 0.2 mm, corresponding resolution 2.5 lp/mm). Ten volunteers without knee problems were examined twice, bilaterally, by 2 different radiology technologists. Results: The total reproducibility of the method was good, offering an HKA reproducibility of ±2.64 in slight flexion and ±1.62 in extension, at 95% confidence. The intra- and inter-observer variations were low with a reduction of the intra-observer variations in all measurements (except one) by a factor of 2.8 on average compared with the original QPR method for conventional film-screen radiography. (orig.)aphy. (orig.)

56

Management of pediatric radiation dose using Agfa computed radiography  

Energy Technology Data Exchange (ETDEWEB)

Radiation dose to patients and its management have become important considerations in modern radiographic imaging procedures, but they acquire particular significance in the imaging of children. Because of their longer life expectancy, children exposed to radiation are thought to have a significantly increased risk of radiation-related late sequelae compared to adults first exposed to radiation later in life. Therefore, current clinical thinking dictates that dose in pediatric radiography be minimized, while simultaneously ensuring sufficient diagnostic information in the image, and reducing the need for repeat exposures. Dose management obviously starts with characterization and control of the exposure technique. However, it extends farther through the imaging chain to the acquisition system, and even to the image processing techniques used to optimize acquired images for display. Further, other factors, such as quality control procedures and the ability to handle special pediatric procedures, like scoliosis exams, also come into play. The need for dose management in modern radiography systems has spawned a variety of different solutions, some of which are similar across different manufacturers, and some of which are unique. This paper covers the techniques used in Agfa Computed Radiography (CR) systems to manage dose in a pediatric environment. (orig.)

Schaetzing, R. [Agfa Corp., Greenville, SC (United States)

2004-10-01

57

Computed and conventional chest radiography: a comparison of image quality and radiation dose  

International Nuclear Information System (INIS)

The aim of this study was to compare the image quality and entrance skin dose (ESD) for film-screen and computed chest radiography. Analysis of the image quality and dose on chest radiography was carried out on a conventional X-ray unit using film-screen, storage phosphor plates and selenium drum direct chest radiography. For each receptor, ESD was measured in 60 patients using thermoluminescent dosemeters. Images were printed on 35 x 43 cm films. Image quality was assessed subjectively by evaluation of anatomic features and estimation of the image quality, following the guidelines established by the protocols of the Commission of the European Communities. There was no statistically significant difference noted between the computed and conventional images (Wilcoxon rank sum test, P>0.05). Imaging of the mediastinum and peripheral lung structures were better visualized with the storage phosphor and selenium drum technique than with the film-screen combination. The patients' mean ESD for chest radiography using the storage phosphor, film-screen combination and selenium drum was 0.20, 0.20 and 0.25 mGy, respectively, with no statistically significant difference with P > 0.05 (?2 tests) Copyright (2005) Blackwell Publishing Asia Pty Ltd

58

Computed and conventional chest radiography: a comparison of image quality and radiation dose.  

Science.gov (United States)

The aim of this study was to compare the image quality and entrance skin dose (ESD) for film-screen and computed chest radiography. Analysis of the image quality and dose on chest radiography was carried out on a conventional X-ray unit using film-screen, storage phosphor plates and selenium drum direct chest radiography. For each receptor, ESD was measured in 60 patients using thermoluminescent dosemeters. Images were printed on 35 x 43 cm films. Image quality was assessed subjectively by evaluation of anatomic features and estimation of the image quality, following the guidelines established by the protocols of the Commission of the European Communities. There was no statistically significant difference noted between the computed and conventional images (Wilcoxon rank sum test, P > 0.05). Imaging of the mediastinum and peripheral lung structures were better visualized with the storage phosphor and selenium drum technique than with the film-screen combination. The patients' mean ESD for chest radiography using the storage phosphor, film-screen combination and selenium drum was 0.20, 0.20 and 0.25 mGy, respectively, with no statistically significant difference with P > 0.05 (chi(2) tests). PMID:16351609

Ramli, K; Abdullah, B J J; Ng, K-H; Mahmud, R; Hussain, A F

2005-12-01

59

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

International Nuclear Information System (INIS)

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.)

60

QC of direct radiography and computed radiography mammography systems: Image quality and average glandular dose  

International Nuclear Information System (INIS)

Today, two technologies have emerged in digital mammography: direct radiology (DR) and computed radiology (CR). The introduction of these technologies leads to different measures and limitations in the quality control (QC) of these mammography systems. The objective of this work was to carry out QC tests on DR and CR mammography systems using the EUREF protocol about image quality and average glandular dose (AGD). These evaluations were made using the same test tools for both SIEMENS DR and CR mammography systems. Image quality was compared in terms of low contrast detectability, exposure time, and ghost factors. Exposure factors were selected clinically. Entrance surface air kerma (ESAK) was calculated from the measured output for PMMA thickness of 2, 3, 4, 5, 6, and 7 cm. The AGD was determined from ESAK and the measured half-value layer (HVL), and the respective conversion factors were obtained from the protocol. Test results indicated that DR mammography system selected a longer exposure time and a higher ghost image factor. CR mammography system yielded mean contrast-detail score higher than that of the DR system, for smaller details. The contrast-detail curves of both systems are shown. They indicate that the DR system has better low contrast detectability than the CR system, as seen from the contrast-detail curve that extends further to the left toward small detail. HVL of DR mammography system is higher than that of CR system. The entrance surface air kerma an system. The entrance surface air kerma and average glandular dose of both systems: direct radiography and computed radiography is shown. For both systems, AGD decreases as PMMA thickness increases; AGD for DR is higher. To conclude, both DR and CR mammography systems performed well within the stated values of the EUREF protocol. However, we found that the DR mammography system operated with higher beam quality that resulted in higher dose and better low contrast detectability. Therefore, DR should not be considered equal to CR mammography system

 
 
 
 
61

Establishment of radiographic exposure chart for non-metallic sample using computed radiography system  

International Nuclear Information System (INIS)

Computed Radiography (CR) which utilises phosphorus imaging plate (IP) technology is one of the most famous candidate modules to replace conventional radiography. This work report the determination of image quality for metallic sample using computed radiography. A target normalized signal-to-noise ratio is set as a reference for the image from the IP in obtaining acceptable image density and sensitivity to permit successful image manipulation. (author)

62

Improvement of lung abnormality detection in computed radiography using multi-objective frequency processing: Evaluation by receiver operating characteristics (ROC) analysis  

International Nuclear Information System (INIS)

Computed radiography (CR) has been shown to have relatively low sensitivity for detection of pulmonary nodules. This poor sensitivity precludes its use as a screening modality despite the low cost, low dose and wide distribution of devices. The purpose of this study was to apply multi-objective frequency processing (MFP) to CR images and to evaluate its usefulness for diagnosing subtle lung abnormalities. Fifty CR images with simulated subtle lung abnormalities were obtained from 50 volunteers. Each image was processed with MFP. We cut chest images. The chest image was divided into two rights and left. A total of 200 half-chest images (100 MFP-processed images and 100 MFP-unprocessed images) were prepared. Five radiologists participated in this study. ROC analyses demonstrated that the detection rate of simulated subtle lung abnormalities on the CR images was significantly better with MFP (Az = 0.8508) than without MFP (Az = 0.7925). The CR images processed with MFP could be useful for diagnosing subtle lung abnormalities. In conclusion, MFP appears to be useful for increasing the sensitivity and specificity in the detection of pulmonary nodules, ground-glass opacity (GGO) and reticular shadow

63

Evaluation of image quality in computed radiography based mammography systems  

Science.gov (United States)

Mammography is the most widely accepted procedure for the early detection of breast cancer and Computed Radiography (CR) is a cost-effective technology for digital mammography. We have demonstrated that CR mammography image quality is viable for Digital Mammography. The image quality of mammograms acquired using Computed Radiography technology was evaluated using the Modulation Transfer Function (MTF), Noise Power Spectrum (NPS) and Detective Quantum Efficiency (DQE). The measurements were made using a 28 kVp beam (RQA M-II) using 2 mm of Al as a filter and a target/filter combination of Mo/Mo. The acquired image bit depth was 16 bits and the pixel pitch for scanning was 50 microns. A Step-Wedge phantom (to measure the Contrast-to-noise ratio (CNR)) and the CDMAM 3.4 Contrast Detail phantom were also used to assess the image quality. The CNR values were observed at varying thickness of PMMA. The CDMAM 3.4 phantom results were plotted and compared to the EUREF acceptable and achievable values. The effect on image quality was measured using the physics metrics. A lower DQE was observed even with a higher MTF. This could be possibly due to a higher noise component present due to the way the scanner was configured. The CDMAM phantom scores demonstrated a contrast-detail comparable to the EUREF values. A cost-effective CR machine was optimized for high-resolution and high-contrast imaging.

Singh, Abhinav; Bhwaria, Vipin; Valentino, Daniel J.

2011-03-01

64

Assessing the impact of computed radiography and PACS  

International Nuclear Information System (INIS)

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

65

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

66

Quality assurance of computed and digital radiography systems  

International Nuclear Information System (INIS)

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

67

Conventional radiography and computed tomography of cardiac assist devices  

International Nuclear Information System (INIS)

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.)

68

High resolution digital radiography and three-dimensional computed tomography  

International Nuclear Information System (INIS)

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 tube systems and discuss the use of these new systems for acquisition of 3-D CT images

69

Validation of a computed radiography device to monitor the HIV-1 RNase H activity  

International Nuclear Information System (INIS)

A commercially available computed radiography (CR) system for dental radiography was used to produce images from radiolabeled polyacrilamide gel electrophoresis (PAGE) assays. Typically, similar investigations require specific and expensive autoradiography devices. The CR unit was characterized in terms of sensitivity and fading by means of a 90Sr source that well simulates the experimental conditions, and then used for quantitative analyses of the human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) polymerase-independent ribonuclease H (RNase H) activity monitored by PAGE analysis. The results showed that the present methodology allows quantifying effectively the RNase H catalyses and that the obtained data are in good agreement with previous reference works. Finally, in order to further validate the present method in terms of relationship between enzyme activity, the rate of products formation and signal intensity, a PAGE analyses of the HIV-1 RNase H inhibition by the known diketo acid derivative RDS1643 was carried out.

70

Validation of a computed radiography device to monitor the HIV-1 RNase H activity  

Science.gov (United States)

A commercially available computed radiography (CR) system for dental radiography was used to produce images from radiolabeled polyacrilamide gel electrophoresis (PAGE) assays. Typically, similar investigations require specific and expensive autoradiography devices. The CR unit was characterized in terms of sensitivity and fading by means of a 90Sr source that well simulates the experimental conditions, and then used for quantitative analyses of the human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) polymerase-independent ribonuclease H (RNase H) activity monitored by PAGE analysis. The results showed that the present methodology allows quantifying effectively the RNase H catalyses and that the obtained data are in good agreement with previous reference works. Finally, in order to further validate the present method in terms of relationship between enzyme activity, the rate of products formation and signal intensity, a PAGE analyses of the HIV-1 RNase H inhibition by the known diketo acid derivative RDS1643 was carried out.

Esposito, F.; Fanti, V.; Marzeddu, R.; Randaccio, P.; Tramontano, E.; Zinzula, L.

2009-08-01

71

Management of pediatric radiation dose using Fuji computed radiography  

International Nuclear Information System (INIS)

This paper describes the technical details of Fuji Computed Radiography (FCR) and its use as it relates to managing pediatric dose for X-ray examinations. Since its introduction in 1983, Fuji (Fuji Photo Film Co., Ltd.) has developed an extensive set of menu selections with default processing algorithms and corresponding display processing parameters modified for all pediatric exam types. Continued development of imaging plate technology, FCR reader design and image processing have all contributed to improving image quality and creating the opportunity to lower the dose required for pediatric exams. Fuji continues to advance CR and electronic imaging technologies; some of these developments, that may enable lower dose examinations for pediatric imaging in the future, are also described in this paper. (orig.)

72

Tracheal images using energy subtraction Fuji computed radiography  

International Nuclear Information System (INIS)

Twenty patients with lesions in the trachea or bronchus underwent energy subtraction Fuji computed radiography (FCR). Images obtained were compared with those from conventional FCR (plain FCR). ''Very clear'' images (in which the contour of the trachea and bronchus could be clearly defined) were obtained in 12/22 (55 %) by energy subtraction FCR and in 3/22 (14 %) by plain FCR; ''clear'' images (in which the contour could be defined) in 9/22 (41 %) by energy subtraction FCR and in 18/22 (82 %) by plain FCR; and ''unclear'' images (in which the contour could not be defined) in 1/22 (5 %) by both methods. Energy subtraction FCR, as well as plain FCR, yielded high image quality for the trachea. Energy subtraction FCR was superior to plain films when tumors existed within the trachea. (Namekawa, K.)

73

Assessment of weld thickness loss in offshore pipelines using computed radiography and computational modeling  

International Nuclear Information System (INIS)

In order to guarantee the structural integrity of oil plants it is crucial to monitor the amount of weld thickness loss in offshore pipelines. However, in spite of its relevance, this parameter is very difficult to determine, due to both the large diameter of most pipes and the complexity of the multi-variable system involved. In this study, a computational modeling based on Monte Carlo MCNPX code is combined with computed radiography to estimate the weld thickness loss in large-diameter offshore pipelines. Results show that computational modeling is a powerful tool to estimate intensity variations in radiographic images generated by weld thickness variations, and it can be combined with computed radiography to assess weld thickness loss in offshore and subsea pipelines.

74

Assessment of weld thickness loss in offshore pipelines using computed radiography and computational modeling  

Energy Technology Data Exchange (ETDEWEB)

In order to guarantee the structural integrity of oil plants it is crucial to monitor the amount of weld thickness loss in offshore pipelines. However, in spite of its relevance, this parameter is very difficult to determine, due to both the large diameter of most pipes and the complexity of the multi-variable system involved. In this study, a computational modeling based on Monte Carlo MCNPX code is combined with computed radiography to estimate the weld thickness loss in large-diameter offshore pipelines. Results show that computational modeling is a powerful tool to estimate intensity variations in radiographic images generated by weld thickness variations, and it can be combined with computed radiography to assess weld thickness loss in offshore and subsea pipelines.

Correa, S.C.A. [Programa de Engenharia Nuclear/COPPE, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Centro Universitario Estadual da Zona Oeste - UEZO, Avenida Manuel Caldeira de Alvarenga, 1203, 23070-200, Rio de Janeiro, RJ (Brazil)], E-mail: scorrea@con.ufrj.br; Souza, E.M. [Programa de Engenharia Nuclear/COPPE, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Departamento de Geologia/IGEO, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Oliveira, D.F. [Programa de Engenharia Nuclear/COPPE, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Silva, A.X. [PEN/COPPE-DNC/Poli-CT, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Lopes, R.T. [Programa de Engenharia Nuclear, COPPE, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Marinho, C.; Camerini, C.S. [CENPES/PDEP/TMEC/PETROBRAS, Ilha do Fundao, Cidade Universitaria, 21949-900, Rio de Janeiro, RJ (Brazil)

2009-10-15

75

Application of digital radiography in the analysis of cultural heritage  

International Nuclear Information System (INIS)

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)

76

Application of digital radiography in the analysis of cultural heritage  

Energy Technology Data Exchange (ETDEWEB)

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)

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

2013-07-01

77

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

International Nuclear Information System (INIS)

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

78

MYTHS vesus reality in computed radiography image quality  

International Nuclear Information System (INIS)

As NDE operation - particularly radiographic testing - ransition form analog to digital technologies such as computed radiography (CR), users are learning that there's more to digital image quality than meets the eye. In fact, there are ultiple factors that determine the final perceived image quality of a computed radiograph. Many of these factors are misunderstood, and some are touted as the ''key parameter'' or ''magic bullet'' in producing optiumum image quality, In reality, such claims are oversimplified, and are more marketing hype than reality. The truth?. Perceived image quality results form the cascaded effects of many factor - such as sharpness, system noise, spot size and pixel size, subject contrast, bit depth, radiographic technique, and so on. Many of these factors are within the control of rdiographers or designers of equipment and media. This paper will explain some of these key factors, dispel some of the myths surrounding them, and will show that qualities such as bigger, smaller, more, or less are not always better when it comes to CR image quality. (authors)

79

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

International Nuclear Information System (INIS)

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.)

80

An investigation of the shielding characteristics of computed radiography cassettes.  

Science.gov (United States)

Computed radiography (CR) systems are rapidly replacing film screen techniques. Previous estimates have been made of the degree of attenuation that occurs as a primary diagnostic X-ray beam passes through a film-screen cassette at different tube potentials. Cassette attenuation is commonly stated in terms of equivalent thickness of lead, which can be calculated using lead attenuation curves. These values can then be subtracted from the shielding requirements calculated for diagnostic X-ray rooms. Since the introduction of CR, no comparison has been made between the attenuation of the old film-screen and the new CR cassettes. In order to perform such a comparison, transmission factors for two CR cassettes and one film-screen cassette were measured, in addition to experimental lead attenuation curves. Lead equivalent thickness values were calculated for all three cassettes using both a semi-theoretical model and measured data. Although there was some discrepancy between the two methods, both found that the new cassettes provided a similar or greater degree of attenuation as the film screen cassette. PMID:18238923

Potts, R; Baker, K; Bridge, L

2008-02-01

 
 
 
 
81

Image quality evaluation of a desktop computed radiography system.  

Science.gov (United States)

The modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) of the Lumisys ACR-2000 desktop computed radiography (CR) reader were measured and compared to equivalent measurements acquired from a Fuji AC-3 CR system. The one-dimensional (1D) MTF was measured from an image of a sharp edge and the 1D NPS was derived from a 2D NPS measured from a uniform field exposure. The energy dependent ideal input signal to noise ratio of the incident x-ray beams was estimated using published x-ray spectra and attenuation coefficients. Measurements were acquired using Agfa, Fuji, and Kodak storage phosphor plates and it was concluded that use of the Fuji plates resulted in the highest system DQE for the ACR-2000. The DQE was measured using exposures of 0.10, 1.0, and 10.0 mR from 70 and 120 kVp x-ray beams filtered with aluminum. The DQE of the Lumisys ACR-2000 was lower than that of the Fuji AC-3. PMID:11190949

Fetterly, K A; Hangiandreou, N J

2000-12-01

82

Application value of computed radiography energy subtraction in detecting pulmonary soft-tissue: comparison with direct digital radiography  

International Nuclear Information System (INIS)

Objective: To compare the efficiency of computed radiography energy subtraction (ES-CR) with direct digital radiography (DR) in detecting the pulmonary soft-tissue signals. Methods: The adult chest phantom including TRG was imaged by ES-CR and DR separately and was estimated by 6 radiologists with 5-value-differentiation method. ROC was used to analyze the performance of two systems. Images of DR and ES-CR of 28 patients with small lung cancer were diagnosed by 3 radiologists. Results: The area under the ROC curves was 0.727 in ES-CR and 0.827 in DR (Z=2.96, P2=5.14, P<0.05). Conclusions: The true positive proportion of DR might be higher than that of ES-CR. ES-CR is inferior to DR in detecting pulmonary soft-tissue signals. (authors)

83

Neutron-computer tomography using real-time neutron radiography  

International Nuclear Information System (INIS)

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

84

Digital subtraction angiography (DSA) using Fuji computed radiography (FCR)  

International Nuclear Information System (INIS)

A vessel phantom suitable for evaluation of spatial and contrast resolution of FCRDSA (Fuji Computed Radiography, digital subtraction angiography) has been developed and used for determining resolution. The effects of iodine concentration, low dose exposure, and acryl thickness on the resolution were evaluated in FCRDSA, and FCRDSA images were compared with film substraction with use of this phantom. It has been proven that limitation of resolution of FCRDSA was 5 % 1 mm and about 1/4 dose exposure compared with conventional film exposure was clinically acceptable. Dye dilution method was useful to determine a program of IVDSA with imaging plate. It has been proven that time to appearance and time to peak of time-concentration curve of dye dilution method closely correlate to time to appropriate image of DSA in the neck, the chest, and the abdomen. 106 cases of IVDSA and 130 cases of IADSA using FCR in Tohoku University Hospital from January through December 1984 were analized. 90 % of IVDSA were clinically useful, and 40 % of IVDSA were equal or superior than the conventional image. IADSA has more excellent image than IVDSA, especially in the head and the extremity. 95 % of IADSA were cllinically useful. Inadequate timing exposure of IVDSA were seen in several cases. Almost all causes of unsuccessful examination were occured by misregistration artifacts, consisting of respiration or cardiac motion in the chest, bowel gas in the abdomen. The aortic arch and branches of the aorta were well opacified by IVDSA. However, vessels of the skull and the exteremity were difficult to diagnose by IVDSA, IADSA is recommended in these cases. (J.P.N.)

85

Daily quality control in computed radiography mammography using the manufacturer phantom  

International Nuclear Information System (INIS)

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)

86

Radiography, computed tomography and magnetic resonance imaging of craniofacial structures in pig.  

Science.gov (United States)

The pig has recently become popular as a large animal experimental model in many fields of biomedical research. The aim of this study is to evaluate the basic anatomical structures in the head region of the pig to lay the groundwork for its practical clinical usage or pre-clinical research in the future. We used three different diagnostic imaging methods: radiography, computed tomography (CT) and magnetic resonance imaging (MRI). The analysis showed that radiographic imaging is suitable only for general evaluation of the facial area of the pig skull. CT images showed excellent spatial definition of bony structures of the whole craniofacial area, and MRI images revealed fine soft tissue details. Radiography is preferentially suited to general assessment of bone structures of the facial skeleton; however, the thick layer of adipose tissue in the craniofacial region of the pig makes the imaging of some parts difficult or even impossible. CT is useful for revealing morphological details of mineralized tissues, whereas MRI is more suitable for soft tissue analysis and the detection of subtle pathologic changes in both bone and soft tissues. Therefore, before using pigs as an experimental model in craniofacial research, it is necessary to evaluate the suitability and disadvantages of potential imaging methods and how appropriate they are for accurate visualization of desired structures. PMID:24261592

Kyllar, M; Stembírek, J; Putnová, I; Stehlík, L; Odehnalová, S; Buchtová, M

2014-12-01

87

Heavy-ion radiography and heavy-ion computed tomography  

International Nuclear Information System (INIS)

Heavy-ion projection and CT radiography is being developed into a safe, low-dose, noninvasive radiological procedure that can quantitate and image small density differences in human tissues. The applications to heavy-ion mammography and heavy-ion CT imaging of the brain in clinical patients suggest their potential value in cancer diagnosis

88

Computer model to optimise contrast in chest radiography  

International Nuclear Information System (INIS)

iograph, was a weak function of kVp and strong function of scatter rejection. This was most evident in thicker regions such as the mediastinum. Dosimetric considerations confirmed that high contrast radiography is best achieved through efficient scatter reduction at high-kVp rather than low scatter removal at low kVp. 34 refs., 2 tabs., 10 figs

89

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

Science.gov (United States)

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 (?) 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 ?=93.1±2.9%, DSC=96.1±3.5% and ACD=1.62±0.92 mm, for the postero-anterior view, while we had ?=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

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

2013-01-01

90

PyRAT - python radiography analysis tool (u)  

Energy Technology Data Exchange (ETDEWEB)

PyRAT is a radiography analysis tool used to reconstruction images of unknown 1-0 objects. The tool is written in Python and developed for use on LINUX and Windows platforms. The tool is capable of performing nonlinear inversions of the images with minimal manual interaction in the optimization process. The tool utilizes the NOMAD mixed variable optimization tool to perform the optimization.

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

2011-01-14

91

Neutron Radiography Analysis of a Transient Liquid Phase Joint  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 visuali...

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

2006-01-01

92

Concrescence: assessment of case by periapical radiography, cone beam computed tomography and micro-computed tomography.  

Science.gov (United States)

The aim of this article was to describe imaging aspects of concrescence analyzed by three imaging modalities. A second molar joined together with a third molar was imaged using digital periapical radiography, cone beam computed tomography (CBCT) and micro-computed tomography (Micro-CT). On periapical radiograph, the mesial root of the third molar is superimposed on the distal root of the second molar. On CBCT images, a large cementum union between bulbous roots was detected, confirming the diagnosis of concrescence. On micro-CT images, the cementum union appeared limited to the apical third of the roots. In conclusion, both computed tomography modalities allowed for the diagnosis of concrescence. However, only micro-CT provided the real extension of the cementum union. PMID:24933768

Neves, Frederico Sampaio; Rovaris, Karla; Oliveira, Matheus Lima; Novaes, Pedro Duarte; de Freitas, Deborah Queiroz

2014-04-01

93

Application of computer-aided design approach for computer simulation of radiography and 3-D tomography  

International Nuclear Information System (INIS)

A powerful computer-aided design package was integrated with computer simulation programs, developed by the authors, for radiographic and 3-D tomographic evaluation of structures and parts. The initial design simulation of two 3-D objects, a tee weld and a tubular weld both containing plane defects, was performed using an interactive program for solid modeling called CATIA taken from the CAD/CAM Laboratory at Ohio State. Ray tracing simulation of the 2-D projections of the objects was then performed for film and real time radiography and was followed by 3-D computer tomography reconstruction. The database consisted of one hundred simulated 2-D projections taken from different angles. Results of the reconstruction are illustrated

94

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

International Nuclear Information System (INIS)

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% (? = 0.33 and ? = 0.39, respectively) and moderate for DR (? = 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.

95

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

Energy Technology Data Exchange (ETDEWEB)

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)

Aquino, Josilto Oliveira de

2009-03-15

96

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

International Nuclear Information System (INIS)

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 agreemenhere 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

97

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

Energy Technology Data Exchange (ETDEWEB)

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

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

98

Digital Detectors: Computed Radiography (CR for All Radiologists  

Directory of Open Access Journals (Sweden)

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 "scintillator" or phosphor, known from screens and image amplifiers. There are 2 groups of DR: the first group is amorphous selenium + TFT pixel backplane and the second is a scintillator + TFT pixel backplane. The first directly converts x-ray into charge (2 steps and the latter first converts x-rays into light and light into charge in a photodiode in each pixel. "nOf course the DR technology is complex and difficult to manufacture in the large formats needed in radiology (14"x17" and explains the high price/unit (>200 k$."nDR can only be justified in a limited number of situations: high throughput (like chest, high labor-cost and lack of radiographers, radiation-dose regulations."nThe technical nature of DR is very sensitive to environmental conditions like vibrations (mobile applications and temperature (Selenium has to be air-conditioned and the portable models are still bulky and costly to put under the bed patients. However, in the future DR prices are expected to come down"n- There are numerous combined systems: lens or fiber coupled CCD systems guiding the x-ray image into a small (and cheap CCD with a bad image quality."nSlit/slot methods moving a small bundle of x-rays and a line-detector over the patient during several seconds exhausting the tube and the patient...."nThere is no perfect system: most have some advantages and some drawbacks and all of them are compromises between quality and price. "nConclusion: Today CR based on powder phosphors is still the best solution in a starter situation where cost and a broad range of ap-plications are important, because it replaces all types of film-screen cassettes by 1 CR cassette, without changes to the x-ray modality and the workflow. Immediately it allows lower doses and a decrease in repeat rates to <1% at a high image quality (with multi-frequency image processing like Agfa Musica."nCR readers are offered in a wide range of sophistication and prices matching most of the needs and budgets of r

Frans Dhaenens

2007-08-01

99

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

CERN Document Server

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...

American Society for Testing and Materials. Philadelphia

2010-01-01

100

Neutron Radiography Analysis of a Transient Liquid Phase Joint  

CERN Document Server

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 diffusion profile of the boron contained in the bonding additives is determined. Parameters of the bonding process are determined quantitatively from this profile, and flaws in the joint are detected.

Ballhausen, H; Eccleston, R S; Gähler, R; Smith, A J; Steuwer, A; Van Overberghe, A

2006-01-01

 
 
 
 
101

Interfacing a computed radiography system in a centralized PACS system through a microcomputer  

International Nuclear Information System (INIS)

Establishing control of the image data flow between a computed radiography system and a host computer presents many problems in a centralized PACS system design. Dedicating the main computer of the PACS system to service on-line acquisition devices will soon overload the system, especially when multiple image acquisition units are present. The authors' approach is to distribute the task of buffering the input image data to a smart file server. Using a low-cost microcomputer as their image file server, they can reduce the burden to the central PACS computer when an image is to be acquired. This paper describes the design of the smart file server for a PCR/SP computed radiography system

102

Computed radiography system using an imaging plate as an x-ray sensor, TCR-201  

International Nuclear Information System (INIS)

The computed radiography system, TCR-201, has been developed through cooperation between Fuji Photo Film Co., Ltd. and Toshiba, with the objects of improving the diagnostic efficiency and accuracy of X-ray examinations. It is a digital radiography system with an imaging plate (IP) as an X-ray sensor. Image reading and recording are performed with a high-definition He-Ne laser scanner. The system provides high-resolution images by advanced variations of image processing such as gradational and spatial frequency enhancement and subtraction. It has wide application in current X-ray systems. (author)

103

Computed radiography in scoliosis. Diagnostic information and radiation dose  

International Nuclear Information System (INIS)

The diagnostic information and radiation dose in scoliosis examinations performed with air-gap technique using stimulable phosphor imaging plates were determined in a prospective study. Overlapping p.a. images of the thoracic and lumbar spine in 9 patients were obtained with 4 different exposure settings according to patient size. Equal exposure settings were used for the 2 images. Two images of 18 were judged inferior in depicting the landmarks of scoliosis measurement, requiring re-exposure. Sixteen images were judged of adequate or good quality. The mean entrance doses in the central beam for the 4 patient groups were in the interval of 0.05 to 0.12 mGy for both images. The skin doses on the breasts were in the range of 0.00 to 0.03 mGy. The presented technique thus results in a low radiation dose with sufficient diagnostic information in radiography of scoliosis. (orig.)

104

Computed radiography in scoliosis. Diagnostic information and radiation dose  

Energy Technology Data Exchange (ETDEWEB)

The diagnostic information and radiation dose in scoliosis examinations performed with air-gap technique using stimulable phosphor imaging plates were determined in a prospective study. Overlapping p.a. images of the thoracic and lumbar spine in 9 patients were obtained with 4 different exposure settings according to patient size. Equal exposure settings were used for the 2 images. Two images of 18 were judged inferior in depicting the landmarks of scoliosis measurement, requiring re-exposure. Sixteen images were judged of adequate or good quality. The mean entrance doses in the central beam for the 4 patient groups were in the interval of 0.05 to 0.12 mGy for both images. The skin doses on the breasts were in the range of 0.00 to 0.03 mGy. The presented technique thus results in a low radiation dose with sufficient diagnostic information in radiography of scoliosis. (orig.).

Jonsson, A. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Jonsson, K. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Eklund, K. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Holje, G. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Pettersson, H. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden)

1995-07-01

105

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

Energy Technology Data Exchange (ETDEWEB)

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)

Machado, Alessandra S.; Oliveira, Davi F.; Silva, Aline S.S.; Nascimento, Joseilson R.; Lopes, Ricardo T., E-mail: alemachado@lin.ifrj.br [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEN/COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Nuclear. Lab. de Instrumentacao Nuclear; Simoes, Heleno, E-mail: hsimoes@confab.com.br [CONFAB Industrial S.A. - Equipamentos, SP (Brazil); Universidade de Taubate (UNITAU), SP (Brazil)

2011-07-01

106

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

International Nuclear Information System (INIS)

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)

107

Risk analysis of radiography as a nondestructive testing method  

International Nuclear Information System (INIS)

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)

108

Digital radiography  

International Nuclear Information System (INIS)

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

109

Comparison of conventional film and computed radiography in neonatal and pediatric intensive care patient evaluations  

International Nuclear Information System (INIS)

A prospective study comparing only portable images generated by a computed radiography system with conventional film radiographs is in progress. The computed radiography system uses a photostimulable imaging plate, an analog-digital converter, an image processor, and an image recorder. More than 200 serial portable examinations in 50 patients are being reviewed. The comparisons include the spectrum of neonatal lung disease, pediatric respiratory distress syndrome, complications of assisted ventilation, and postoperative chest, abdomen, and muskuloskeletal applications. The images are reviewed in a blinded fashion by four experienced general radiologists, two pediatric radiologists, and two neonatologists. The following parameters are assessed: image quality and resolution, depiction of normal structures, radiation dosimetry, and diagnostic accuracy

110

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

International Nuclear Information System (INIS)

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

111

Clinical evaluation of irreversible data compression for computed radiography of the chest  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Efficient data compression is essential for practical daily operation of computed radiography (CR) systems. In this study the clinical applicability of type III irreversible high data compression using an FCR 9501 chest unit (Fuji Photo Film, Tokyo, Japan) was evaluated. Sixty-eight normal and 93 various abnormal cases, with an additional 15 cases of lung cancers with solitary lung nodules, were selected from the file. A pair of hard copies of original images and images reconstructed using ty...

Egashira, Kanji; Nakata, Hajime; Watanabe, Hideyuki; Uchida, Kazuhiko; Nakamura, Katsumi; Ishino, Yoichi; Horino, Kenji; Yoshikawa, Rie

1998-01-01

112

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

International Nuclear Information System (INIS)

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)

113

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

International Nuclear Information System (INIS)

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 ma intraoral radiography with this method may be useful for training in intraoral radiographic technique for dental students. (author)

114

Cephalometric radiography and computed tomography in infants undergoing craniofacial surgery  

International Nuclear Information System (INIS)

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)

115

Evaluation of selective alveolo-bronchography with Fuji computed radiography and x-ray CT  

International Nuclear Information System (INIS)

Selective alveolo-bronchography (SAB) has been routinely used to evaluate anatomical changes in the bronchiole and its distal air spaces. A narrowing of the bronchiole and abnormal pooling of contrast medium in the destroyed air space are the prime findings. Since the object of radiography is extremely thin, direct magnification radiography is mandatory to obtain radiologic details. However, the problem with this technique is that radiographic quality varies depending upon the size of the patient and the concentration of contrast medium to be introduced in the lung. This study had two goals. One was to improve the image quality of SAB by Fuji Computed Radiography (FCR). FCR provides radiographs with a good contrast and stable density throughout a wide range of exposure factors which occur in the use of SAB. The other goal was to separately evaluate morphological abnormalities in the outer and inner zones of the lung using X-ray CT. This idea was derived from our observations in positron emission tomography using 13N which revealed air trapped in the outer layer of the lung in diffuse panbronchiolitis. Fourteen patients underwent SAB, including two cases of bronchiectasis, one of cancer, one of silicosis, one of post-inflammatory scar, four of diffuse panbronchiolitis and five of chronic pulmonary emphysema. Of these fourteen cases ten and twelve cases received FCR and CT examinations, respectively. (author)

116

Radiographic features of enostosis determined with limited cone-beam computed tomography in comparison with rotational panoramic radiography  

International Nuclear Information System (INIS)

Radiographic findings of enostosis often resemble those of focal condensing osteomyelitis of inflammatory origin, and the location and state of these lesions cannot be precisely diagnosed using rotational panoramic radiography. Consequently, a differential diagnosis approach is required. This study examined the situation and characteristics of mandibular enostosis using limited cone-beam computed tomography (CBCT) in comparison with rotational panoramic radiography. Forty-four radiopaque lesions were examined on rotational panoramic radiography and CBCT. The lesions were diagnosed as enostosis from radiographic features on CBCT that had been performed for other clinical diagnoses or dental treatments. For each lesion, the site, margin, density, and relationship to tooth roots were determined on rotational panoramic radiography, and the shape of the cortical bone was determined on CBCT. Enostosis occurred in the premolar region of the mandible in 25 cases (57%) and displayed numerous patterns of relationships to adjacent teeth on rotational panoramic radiography. All lesions displayed an ovoid external form on rotational panoramic radiography. On CBCT, enostosis arose from buccal cortical bone in 13 cases and from lingual cortical bone in 25 cases; a lingual origin was suspected in the remaining six cases. The periodontal ligament space of adjacent teeth near the lesion was clearly apparent on both rotational panoramic radiography and CBCT. Rotational panoramic radiography and occlusal radiography cannot diagnose exactly the location and state of enostosis. The diagnosis of enostosis can be difficult for lesions influenced by secondary infection in the roots of surrounding teeth; diagnosis in these cases may be facilitated by clarifying the manifestation involving the periodontal ligament space of adjacent teeth and confirming bone thickening arising from the inner surface of cortical bone. (author)

117

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

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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.)

118

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

International Nuclear Information System (INIS)

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)

119

Comparison of conventional radiography with cone beam computed tomography for detection of vertical root fractures. An in vitro study  

International Nuclear Information System (INIS)

To assess the diagnostic accuracy of cone beam computed tomography (CBCT) in comparison with conventional radiography for vertical root fractures, 50 of 100 teeth were subjected to vertical root fracture (VRF) and then placed in dry mandibles. 3D scans were obtained for all teeth, and conventional radiographs were used as control images. All the images were assessed by 6 observers, who determined the presence of root fractures by using a 5-point confidence rating scale. The mean area under the curve (Az) for CBCT was 0.91, and that for conventional radiography was 0.64. The difference between the modalities was statistically significant (P=0.003). On the basis of interclass coefficient, inter-observer agreement for CBCT was 0/750, and that for conventional radiography was 0/637. Thus CBCT was shown to be significantly better than conventional periapical radiography for diagnosis of vertical root fractures in vitro. (author)

120

Measurement and analysis of release isentropes using proton radiography (u)  

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Off-Hugoniot measurements are needed to further develop predictive models that accurately describe the behavior of metals undergoing phase transitions. Predictive modeling of phase transitions is essential for LANL to meet its programmatic objectives. Understanding the dynamic evolution of density as a function of time during the release process is important to developing high fidelity equation of state models. This is particularly true for metals that have a degree of complexity, such as a solid-solid phase transition. The equations-of-state (EOS) for metals with complexity are more difficult to measure and to model, and states far away from where measurements are easily made can be poorly known. Accurate density measurements can provide us with additional fundamental information that can be used to further constrain the equation of state for a material. Currently release isentrope information is obtained from shock experiments at a sample window interface using optical velocimetry. This data is highly convoluted due to wave interactions between the sample window-interface making it difficult to infer physical processes happening within the material. Proton radiography has the ability to probe the release waves in-situ before these wave interactions can take place. Since multiple radiographs are obtained in each experiment, pRad provides the unique capability of being able to measure both density and wave evolution within the material. The measurement of release wave densities, however, presents new challenges for pRad since the release wave of a shocked transition is not a step function but instead a ramped wave. Previous pRad experiments have generally measured density jumps over step transitions; therefore, new analysis techniques will have to be developed to measure the ramped density change of a release isentrope. Once developed, these new analysis techniques can also be used for experiments that involve ramped compression. This kind of compression is being used to measure states close to an isentrope. The ability analyze ramp wave data is an essential component to further the use of proton radiography to study any off-Hugoniot behavior. Wave speeds in materials depend upon the speed of sound which in turn is a function of pressure in the material. At higher pressures the sound speed is faster; at lower pressures the sound speed is slower; this is what causes shock waves to form. This same effect causes the shape of release waves to change with time. The wave will be running faster at the top and slower at the bottom, its slope steeper at the top and less at the bottom due to pressure changes. These are unsteady waves. WONDY simulations of these wave shape characteristics are shown in Fig. 1 for a Cu symmetric impact. We will need to look at how the shape of the wave changes over time and affects the measurement of the density as a function of time. Additionally we need to quantify the uncertainties in the spatial and density measurements as a function of ramp rate and shock strength. We will look at aluminum or copper to validate the analysis techniques that will need to be developed. Finally, we will perform shock loaded phase transition experiments on iron, zirconium, and tin using the developed analysis techniques for incorporation into predictive models. The iron (and possibly tin) experiments will introduce a new degree of complexity because of the existence of a rarefaction shock in the release wave.

Schwartz, Cynthia L [Los Alamos National Laboratory; Rigg, Paulo A [Los Alamos National Laboratory; Cherne, Frank J [Los Alamos National Laboratory; Hixson, Rob S [Los Alamos National Laboratory; Greff, Carl W [Los Alamos National Laboratory

2011-01-25

 
 
 
 
121

An investigation of automatic exposure control calibration for chest imaging with a computed radiography system  

Science.gov (United States)

The purpose of this study was to examine the use of three physical image quality metrics in the calibration of an automatic exposure control (AEC) device for chest radiography with a computed radiography (CR) imaging system. The metrics assessed were signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and mean effective noise equivalent quanta (eNEQm), all measured using a uniform chest phantom. Subsequent calibration curves were derived to ensure each metric was held constant across the tube voltage range. Each curve was assessed for its clinical appropriateness by generating computer simulated chest images with correct detector air kermas for each tube voltage, and grading these against reference images which were reconstructed at detector air kermas correct for the constant detector dose indicator (DDI) curve currently programmed into the AEC device. All simulated chest images contained clinically realistic projected anatomy and anatomical noise and were scored by experienced image evaluators. Constant DDI and CNR curves do not appear to provide optimized performance across the diagnostic energy range. Conversely, constant eNEQm and SNR do appear to provide optimized performance, with the latter being the preferred calibration metric given as it is easier to measure in practice. Medical physicists may use the SNR image quality metric described here when setting up and optimizing AEC devices for chest radiography CR systems with a degree of confidence that resulting clinical image quality will be adequate for the required clinical task. However, this must be done with close cooperation of expert image evaluators, to ensure appropriate levels of detector air kerma.

Moore, C. S.; Wood, T. J.; Avery, G.; Balcam, S.; Needler, L.; Beavis, A. W.; Saunderson, J. R.

2014-05-01

122

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

International Nuclear Information System (INIS)

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

123

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

International Nuclear Information System (INIS)

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

124

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

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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. Introduction

Chee Kin Lim

2013-04-01

125

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

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english 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 skul [...] l 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.

Chee Kin, Lim; Montague N, Saulez; Adrienne, Viljoen; Ann, Carstens.

126

A Monte Carlo Analysis of the Lead Screen Impact on Film Radiography Image Formation  

Science.gov (United States)

Sandwiching the radiography film between lead screens is a very common practice in either industrial or medical radiography. The motive behind this practice is to increase the efficiency of the energy deposition into the film. In contrast with the medical radiography, the cases brought into the attention of the industrial radiographers show a large variation and screen-film-screen combination designed for one case can not be the optimum choice for another case. In this work, lead screen impact on the image formation has been analyzed through Monte Carlo computations for a large variety of combinations. General trends that need to be taken into consideration in film-screen designs have been determined.

Inanc, Feyzi

2003-03-01

127

Portal localization images using computed radiography for high-energy electron beam therapy  

International Nuclear Information System (INIS)

Portal localization images for high-energy electron beam therapy are necessary to confirm the treatment field by comparing them with a simulation image obtained before treatment or portal verification images after treatment. In this study, portal localization images were acquired using the computed radiography (CR) system and bremsstrahlung X-rays generated in the electron beam irradiations. All images obtained with phantom and the irradiations of in the electron energy of 8, 10, 12 and 15 MeV were feasible for clinical use. The CR system used in this study included general diagnostic imaging cassette and storage phosphor plate, but none of other special devices. The system can usually supply portal localization images, which maintains the quality assurance of high-energy electron beam therapy. (author)

128

Computed radiography systems performance evaluation;Avaliacao de desempenho de sistemas de radiografia computadorizada  

Energy Technology Data Exchange (ETDEWEB)

The performance of a computed radiography system was evaluated, according to the AAPM Report No. 93. Evaluation tests proposed by the publication were performed, and the following nonconformities were found: imaging p/ate (lP) dark noise, which compromises the clinical image acquired using the IP; exposure indicator uncalibrated, which can cause underexposure to the IP; nonlinearity of the system response, which causes overexposure; resolution limit under the declared by the manufacturer and erasure thoroughness uncalibrated, impairing structures visualization; Moire pattern visualized at the grid response, and IP Throughput over the specified by the manufacturer. These non-conformities indicate that digital imaging systems' lack of calibration can cause an increase in dose in order that image prob/ems can be so/ved. (author)

Xavier, Clarice C.; Nersissian, Denise Y.; Furquim, Tania A.C. [Universidade de Sao Paulo (IEE/USP), SP (Brazil). Inst. de Eletrotecnica e Energia

2009-07-01

129

A study of image processing condition of mammography using FCR (Fuji Computed Radiography)  

International Nuclear Information System (INIS)

Image processing conditions of mammography using FCR (Fuji Computed Radiography) to detect mass shadow, marginal findings and microcalcification of breast cancer were examined. The subjects of the examination for mass shadow and marginal finding were 25 cases out of 55 breast cancers operated from December 1986 to August 1988. Three surgeons and two radiologists evaluated processing conditions. The optimum conditions of spatial frequency enhancement were RN(1 or 3)RT(P)RE(1.0) for mass shadow and RN(7)RT(P)RE(2.0) for marginal finding under routine gradational enhancement condition. ROC curves obtained from the phantom with a granule of aluminum were used to optimize image processing condition for microcalcification. It was shown that GT(M)GA(1.0)GC(0.6)RN(9)RT(F)RE(4.0) gave the best detectability among five image processing conditions. (author)

130

Clinical evaluations of intra-arterial subtraction angiography using Fuji computed radiography  

International Nuclear Information System (INIS)

Intra-arterial subtraction angiography(IADSA) using Fuji computed radiography(FCR) was performed on 130 patients with cervical, pelvic, peripheral and abdominal diseases. It was compared with conventional angiography(radiographs produced by combining photographic film with an intensifying screen) performed on same patients. Radiographs produced by FCR were better than conventional radiographs in cervical, pelvic and peripheral angiography. In the abdominal angiography using FCR, there was misregistration artifact in some cases, but in hepatic angiography, the new radiographs under the injection of small amount of contrast medium(about 10ml) and the short exposure duration(about 10 seconds) were excellent. It was as valuable as conventional angiography (infusion hepatic angiography) for diagnosing hepatic neoplasms. (author)

131

Digital Radiography and Computed Tomography Project -- Fully Integrated Linear Detector ArrayStatus Report  

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The field-portable Digital Radiography and Computed Tomography (DRCT) x-ray inspection systems developed for the Project Manager for NonStockpile Chemical Materiel (PMNSCM) over the past 13 years have used linear diode detector arrays from two manufacturers; Thomson and Thales. These two manufacturers no longer produce this type of detector. In the interest of insuring the long term viability of the portable DRCT single munitions inspection systems and to improve the imaging capabilities, this project has been investigating improved, commercially available detectors. During FY-10, detectors were evaluated and one in particular, manufactured by Detection Technologies (DT), Inc, was acquired for possible integration into the DRCT systems. The remainder of this report describes the work performed in FY-11 to complete evaluations and fully integrate the detector onto a representative DRCT platform.

Tim Roney; Robert Seifert; Bob Pink; Mike Smith

2011-09-01

132

Optimisation of performance for computed radiography in the West of Scotland  

International Nuclear Information System (INIS)

This paper describes experiences in the introduction of computed radiography systems to hospitals within the West of Scotland. Setting of automatic exposure control levels has enabled dose-area product values to be maintained at 160 cGy cm2 for lumbar spine antero-posterior (AP), 250 cGy cm2 for lumbar spine lateral, 210 cGy cm2 for pelvis AP and 260 cGy cm2 for abdomen AP. The study looks at dose levels achieved after 8 y in use and compares the dose levels found from surveys undertaken in 2007 and in 2010. The effects of raising tube potentials on image quality in terms of details and on contrast to- noise ratio (CNR) were assessed. The results showed that CNR details seen in test images at tube potentials of 85-90 kV did not differ significantly from those with lower potentials and gave lower entrance surface doses. (authors)

133

Optimization of digital mammography resolution using magnification technique in computed radiography  

International Nuclear Information System (INIS)

To determine whether magnified digital mammography using a computed radiography system can produce better spatial resolution by reducing the focus-object distance, and to define the optimal magnification factor when a large x-ray tube focal spot is used for digital mammography using a CR system. Digital images obtained using computed radiography of a breast phantom were obtained using various magnification factors. Up to twelve acrylic blocks each measuring one centimeter in height were used to increase the distance between the breast phantom and the base plate (screen holder), in order to create the magnification images. The large (0.3 mm) focal spot of the x-ray tube was used for the entire series of images. Three radiologists participated in the evaluation of the images, in order to determine which had the best resolution. The resolving ability of the line pair structures and image clarity of the detectable artificial microcalcifications (specs) were the two factors used to determine the resolution of the images. The images were not compressed and the viewing conditions, including the magnification factors, brightness and contrast, were fixed. The images were displayed on four high resolution PACS dedicated monitors (5 mega pixel LCD, BARCO Belgium). A focus-object distance of 590 mm and a source-to-image receptor distance of 650 mm (set by the manufacturer) resulted in the best resolution, when combined with a magnification factor of 1.1. All three radiologists agreed on this result. Two of the radiologists believed that at least two more line pairs were better separated on the magnified image having the best resolution than on the unmagnified image, while one radiologist believed that three more line pairs were better separated on this magnified image. Using images with still larger magnification factors did not improve the resolution due to edge blurring. It was easier to determine the resolving power by means of the line-pair structures than by assessing the clarity of the artificial microcalcifications

134

Effects of x-ray spectra on the DQE of a computed radiography system  

International Nuclear Information System (INIS)

The effect of incident x-ray beam quality on the measured detective quantum efficiency (DQE) of a computed radiography system was investigated. The incident x-ray beams used had peak tube potentials of 70, 95, and 120 kVp, were filtered with various thicknesses of a 'patient equivalent phantom' (PEP), aluminum, and copper, and provided a consistent exposure to the storage phosphor. For each peak tube potential and filter combination, the one-dimensional modulation transfer function and noise power spectrum were measured and the square of the incident signal-to-noise ratio was estimated. The spatial frequency dependent DQE was calculated from these data. The DQE was integrated to provide an overall estimate of the efficiency and frequency response of the computed radiography system for the various x-ray beams. There was found to be a wide range of integral DQE (IDQE) values for the peak tube potential and filter combinations used. For example, the IDQE ranged from 3.0 to 0.9 mm-2 using the peak tube potential and filter combinations 70 kVp with 5.1 cm PEP and 120 kVp with 30.3 cm PEP, respectively. Finally, peak tube potential and filter combinations 70 kVp with 10.2 cm PEP and 120 kVp with 20.2 cm PEP were chosen as standard x-ray beams that will be used at our facility to measure the DQE of digital radiographic imaging systems for evaluation and acceptance testing

135

Effects of x-ray spectra on the DQE of a computed radiography system.  

Science.gov (United States)

The effect of incident x-ray beam quality on the measured detective quantum efficiency (DQE) of a computed radiography system was investigated. The incident x-ray beams used had peak tube potentials of 70, 95, and 120 kVp, were filtered with various thicknesses of a "patient equivalent phantom" (PEP), aluminum, and copper, and provided a consistent exposure to the storage phosphor. For each peak tube potential and filter combination, the one-dimensional modulation transfer function and noise power spectrum were measured and the square of the incident signal-to-noise ratio was estimated. The spatial frequency dependent DQE was calculated from these data. The DQE was integrated to provide an overall estimate of the efficiency and frequency response of the computed radiography system for the various x-ray beams. There was found to be a wide range of integral DQE (IDQE) values for the peak tube potential and filter combinations used. For example, the IDQE ranged from 3.0 to 0.9 mm(-2) using the peak tube potential and filter combinations 70 kVp with 5.1 cm PEP and 120 kVp with 30.3 cm PEP, respectively. Finally, peak tube potential and filter combinations 70 kVp with 10.2 cm PEP and 120 kVp with 20.2 cm PEP were chosen as standard x-ray beams that will be used at our facility to measure the DQE of digital radiographic imaging systems for evaluation and acceptance testing. PMID:11243349

Fetterly, K A; Hangiandreou, N J

2001-02-01

136

Entrance surface air kerma to patients during chest computed radiography in the United Republic of Tanzania  

International Nuclear Information System (INIS)

Computed radiography (CR) has the potential to improve the image quality through its image processing capabilities as well as reducing patient doses. However, during transition period from analogue to digital modality, there can be a tendency to maintain the exposure parameters that are used in film-screen imaging. This tendency can lead to higher patient doses than is necessary. Such transition is currently taking place in Tanzania and 5 CR facilities are in clinical use. The main objective of this study was to determine the entrance surface air kerma (ESAK) during chest computed radiography of adult patients so as to monitor patient doses during this transition. A previously applied method was used to determine ESAK to 20 adult patients at each facility. The x-ray tube output for each tube potential in clinical use was measured using model 6000-528, 30 cm3 ionization chamber and Model 4000 M+-SI both manufactured by Fluke Biomedical, New York. The energy response of this dosimetry system as stated by manufacturer is 7% over 50-150 kVp range. From the x-ray output and recorded patient exposure parameters, the incident air kerma values (IAKs) were calculated. The ESAK values (ESAKs) were then derived on basis of IAKs and backscatter factor. The ESAKs obtained at 3 facilities as part of ongoing study are presented. The results show that the mean ESAKs at two hospitals were higher than the national average value of 300 ?Gy for 400 film-screen system and abov0 ?Gy for 400 film-screen system and above the recommended diagnostic reference level of 300 ?Gy. This suggests the need to train the radiology personnel towards optimized practice

137

Comparison of computed radiography with conventional film-screen-technique in equine limb radiology  

International Nuclear Information System (INIS)

Computed radiographic systems have been introduced in 1981 by Fuji Photo Co., Ltd. Tokyo. This radiographic technology uses a plate made by photo-stimuable phosphor, which stores X-ray energy. The X-ray image information is scanned by a laser and then collected into a photomultiplier tube which converts it into digital signals. The image signals that are sent into the image processor are processed digitally and can be stored. Reading parameters for each anatomical location are completely menu-guided. An interactive workstation allows manipulation of contrast, detail and image noise. Repeated examinations with different X-ray doses for the evaluation of diagnostic important structures are often necessary in horse radiology. The image plate can accommodate a wide range of radiographic exposures while maintaining a good density. The improved linear response allows a decrease of repeated examination owing to initial incorrect exposures. X-ray image quality between computed radiography-system and conventional one is compared, the advantages include several attributes: The sensitivity and dynamic range of the radiation detector are automatically adjusted to the exposure level and exposure range of the stored image. Therefore, the digital signals are normalized for a wide range of radiographic exposure conditions. Soft tissue and skeletal images are evaluated in one examination. The computed radiology is particularly useful in identification of fine detail information in horse radiology. (author)

138

Radiography - A new field among health sciences in Finland  

International Nuclear Information System (INIS)

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

139

Image quality of supine chest radiographs: intra-individual comparison of computed radiography and low-dose linear-slit digital radiography  

International Nuclear Information System (INIS)

The purpose of this retrospective study was to intra-individually compare the image quality of computed radiography (CR) and low-dose linear-slit digital radiography (LSDR) for supine chest radiographs. A total of 90 patients (28 female, 62 male; mean age, 55.1 years) imaged with CR and LSDR within a mean time interval of 2.8 days ± 3.0 were included in this study. Two independent readers evaluated the image quality of CR and LSDR based on modified European Guidelines for Quality Criteria for chest X-ray. The Wilcoxon test was used to analyse differences between the techniques. The overall image quality of LSDR was significantly better than the quality of CR (9.75 vs 8.16 of a maximum score of 10; p < 0.001). LSDR performed significantly better than CR for delineation of anatomical structures in the mediastinum and the retrocardiac lung (p < 0.001). CR was superior to LSDR for visually sharp delineation of the lung vessels and the thin linear structures in the lungs. We conclude that LSDR yields better image quality and may be more suitable for excluding significant pathological features of the chest in areas with high attenuation compared with CR. (orig.)

140

Slot-Scan Digital Radiography of the Lower Extremities: a Comparison to Computed Radiography with Respect to Image Quality and Radiation Dose  

International Nuclear Information System (INIS)

To compare the slot-scan digital radiography (SSDR) of the lower extremity region and the computed radiography (CR) method with respect to the image quality and radiation exposure. We enrolled 54 patients who underwent both the SSDR and CR of the lower extremities. The study evaluated and statistically compared the image quality of four features (outer cortex, inner cortex, trabeculae and intermuscular fat) at six different levels (pelvis, hip, femur, knee, tibia and ankle) between each method. The image quality was evaluated using a visibility scale, and the entrance skin dose was measured using a dosimeter at three different levels of a phantom (hip, knee, and ankle). The mean image visibility scale values for the SSDR method were significantly higher than for the CR method. The entrance skin dose for the SSDR method was 278 ?Gy at each level, compared to the entrance skin doses of the CR method, which were 3,410 ?Gy for the hip, 1,152 ?Gy for the knee, and 580 ? Gy for the ankle. Both the image quality and patient entrance skin dose data suggest that the SSDR method is superior to the CR method for the lower extremity musculoskeletal examination

 
 
 
 
141

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  

International Nuclear Information System (INIS)

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 ?Sv 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)

142

Radiologic analysis of femoral acetabular impingement: from radiography to MRI  

Energy Technology Data Exchange (ETDEWEB)

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.)

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

143

Digital radiography  

International Nuclear Information System (INIS)

The term 'Digital Radiography' covers all X-ray techniques which produce a projected image with the help of digital imaging techniques, which are very similar to a conventional X-ray film image. The advantage of 'Digital Radiography' is the possibility of digital image processing, like the subtraction technique, the selective material filtering technique and the quantitative image plotting technique. With the equipments now in use, the digital projected image is produced by the line or on an even level. One example of the in-line projected image is the so-called 'topogram', produced via computed tomography equipment. With the help of an X-ray video chain, it is possible to produce digital images on an even level. This technique is used, for example, for 'digital video subtraction angiography' (DVSA). Today, digital radiography is clinically used only in the 'DVSA' and the 'topogram' systems. A survey of the clinical use and the improved future possibilities of digital radiography is given, and the special features of the method are discussed. (orig.)

144

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

145

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

International Nuclear Information System (INIS)

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)

146

Computer and manipulator assisted positioning of medical instruments based on digital radiography  

International Nuclear Information System (INIS)

The studies were aimed at establishing techniques for a computer and manipulator assisted positioning of medical instruments within the body, and to verify the feasibility of the techniques. Points of main interest were: -Definition of the position of targets or target volumes within the human body based on diagnostic images data obtained by digital radiography. - Accurate positioning of instruments at the targets or target volumes. A system developed for this purpose consists of the following main components: - Image generation and evaluation - definition and correlation of positions - positioning of instruments. The process of image generation is described by a mathematical method, the radiation cone being defined in a 3D image coordinate system. For a description of the position of the target spot, a patient coordinate system was established. For the positioning and handling of the instruments, a remote-controlled instrument (manipulator) was developed. The model chosen for experimental simulation of the entire computer and manipulator assisted positioning of medical instruments was a phantom of a juvenile bone cyst in the femur. (UWa)

147

An x-ray imaging system for digital radiography and computed tomography  

International Nuclear Information System (INIS)

Full text: This project investigated the use of an x-ray image intensifier (XRII) for projection radiography and computed tomography. The XRII allows the conversion of x-rays to visible light with an associated gain in brightness. The resultant image can be acquired digitally by means of a CCD camera coupled to the XRII output. Unfortunately, the image-intensifier-CCD-digitizer imaging chain produces a number of defects that degrade image quality. Consequently, the quantitative information contained in such images is also severely compromised. The defects identified were signal amplitude non-linearity, dark current offset, flare, spatial distortion, and brightness non-uniformity. These were characterised, and corrective procedures implemented as far as possible by image processing. The defect-corrected images were then utilised to investigate the viability of the experimental beam-line for computed tomography. The XRII allows rapid simultaneous acquisition of the data necessary to reconstruct many contiguous cross-sectional slices through an object. These slices may then be used to build three-dimensional image reconstructions of an object. The reconstructed images showed spatial discrimination of at least sub-millimetre resolution but there was evidence of ring and streak artefacts. A test object was also constructed to test the linear attenuation discrimination of the system. Measured attenuation values were found to be in good agreement with values calculated from theoretical tabulations. Copyright (1999) Australian X-ray Analytical Association Inc

148

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

Science.gov (United States)

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 (1?) 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 (1?) 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.

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

2014-11-01

149

Low cost, high resolution x-ray detector system for digital radiography and computed tomography  

International Nuclear Information System (INIS)

The authors have designed and evaluated a novel design of line array x-ray detector for use with digital radiography (DR) and computed tomography (CT) systems. The Radiographic Line Scan (RLS) detector is less than half the cost of discrete multi-channel line array detectors, yet provides the potential for resolution to less than 25 microm at energies of 420 kV. The RLS detector consists of a scintillator fiber-optically coupled to a thermo-electrically cooled line array CCD. Gadolinium oxysulfide screen material has been used as the scintillator, in thicknesses up to 250 microm. Scintillating glass, which is formed into a fiber optic bundle, has also been used in thicknesses up to 2 mm. The large 2.5 mm by 25 microm CCD cells provide high dynamic range while preserving high resolution; the 2.5 mm dimension is oriented in the x-ray absorption direction while the 25 microm dimension is oriented in the resolution direction. Servo controlled thermo-electric cooling of the CCD to a fixed temperature provides reduction of dark current and stabilization of the output. Greater dynamic range is achieved by reducing the dark current, while output stabilization reduces the need for frequent calibration of the detector. Measured performance characteristics are presented along with DR and CT images produced using the RLS detector

150

Performance evaluation of a 'dual-side read' dedicated mammography computed radiography system  

International Nuclear Information System (INIS)

The image quality of a dedicated mammography computed radiography (CR) system was characterized. A unique feature of this system is that it collects image signals from both sides of the storage phosphor. Measurements of the modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) were made. This work included improvements in our measurement methods to specifically account for the detrimental effects of system glare on the MTF and to accurately characterize the low-frequency NPS components. Image quality measurements were performed using a 25 kVp beam filtered with 2 mm Al and an exposure range of 1 to 100 mR (87 to 870 ?Gy). The DQE was found to decrease with increasing exposure due to an increased contribution of storage phosphor structure noise. The DQE of this system was compared to similar measurements made using a standard CR system. The dual-side read system demonstrated superior DQE compared to the standard system. The decrease in DQE with increasing exposure was more severe for the standard system than the dual-side read system. This finding suggests that the CR system noise was reduced for the dual-side read system compared to the standard system

151

Performance evaluation of a "dual-side read" dedicated mammography computed radiography system.  

Science.gov (United States)

The image quality of a dedicated mammography computed radiography (CR) system was characterized. A unique feature of this system is that it collects image signals from both sides of the storage phosphor. Measurements of the modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) were made. This work included improvements in our measurement methods to specifically account for the detrimental effects of system glare on the MTF and to accurately characterize the low-frequency NPS components. Image quality measurements were performed using a 25 kVp beam filtered with 2 mm Al and an exposure range of 1 to 100 mR (87 to 870 microGy). The DQE was found to decrease with increasing exposure due to an increased contribution of storage phosphor structure noise. The DQE of this system was compared to similar measurements made using a standard CR system. The dual-side read system demonstrated superior DQE compared to the standard system. The decrease in DQE with increasing exposure was more severe for the standard system than the dual-side read system. This finding suggests that the CR system noise was reduced for the dual-side read system compared to the standard system. PMID:12906203

Fetterly, Kenneth A; Schueler, Beth A

2003-07-01

152

Receiver operating characteristic curve evaluation on computed radiography: an experimental study  

International Nuclear Information System (INIS)

Objective: To get the maximum information from computed radiography (CR) output images by changing post-processing parameters. Methods: Six experimental photos of polypropylene balls of 2.0 mm in diameter were taken by means of one time X-ray exposing on an imaging plate (IP) with different post-processing parameters including rotation amount (GA), gray gradation type (GT), rotation center (GC), shifting amount (GS), frequency rank (RN), frequency type (RT), and degree of enhancement (RE). 6 photos were viewed by three students and one radiologist on a 6000 lx illuminance viewbox. Receiver operating characteristic (ROC) curves were made by means of 5-value-differentiation method. Results: The largest mean area value (Az) below ROC curves of a low contrast experimental photo with post-processing parameters GA=1.0, GT=A, GC=1.6, GS=0.3, RN=4.0, RT=R and RE=3.0 was 0.96, and the maximum information was obtained. The smallest mean area value (Az) was 0.78 with changed post-processing parameters GA=0.8, GS=-0.2 and RE=0.5 while other parameters were not changed. The minimum information was obtained from this photo. Conclusion: In order to get the maximum information from a CR output image, the post-processing parameters should be suitably selected

153

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

International Nuclear Information System (INIS)

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)

154

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

Science.gov (United States)

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

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

2011-09-01

155

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

International Nuclear Information System (INIS)

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 findingindings; 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 exposure. If similar TCT findings observed in such patients, treatment for tuberculosis should be considered

156

Computed Tomography and Computed Radiography of late Bronze Age Cremation Urns from Denmark : An interdisciplinary attempt to develop methods applied in Bioarchaeological cremation research  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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. Microexcav...

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

2012-01-01

157

Diagnostic quality of 50 and 100 um computed radiography compared with screen-film mammography in operative breast specimens  

Science.gov (United States)

Objective To compare reader ratings of the clinical diagnostic quality of 50 and 100 ?m computed radiography (CR) systems with screen–film mammography (SFM) in operative specimens. Methods Mammograms of 57 fresh operative breast specimens were analysed by 10 readers. Exposures were made with identical position and compression with three mammographic systems (Fuji 100CR, 50CR and SFM). Images were anonymised and readers blinded to the CR system used. A five-point comparative scoring system (?2 to +2) was used to assess seven quality criteria and overall diagnostic value. Statistical analysis was subsequently performed of reader ratings (n=16 925). Results For most quality criteria, both CR systems were rated as equivalent to or better than SFM. The CR systems were significantly better at demonstrating skin edge and background tissue (p<1×10?5). Microcalcification was best demonstrated on the CR50 system (p<1×10?5). The overall diagnostic value of both CR systems was rated as being as good as or better than SFM (p<1×10?5). Conclusion In this clinical setting, the overall diagnostic performance of both CR systems was as good as or better than SFM, with the CR50 system performing better than the CR100. PMID:22096218

Pagliari, C M; Hoang, T; Reddy, M; Wilkinson, L S; Poloniecki, J D; Given-Wilson, R M

2012-01-01

158

Interobserver agreement and performance score comparison in quality control using a breast phantom: screen-film mammography vs computed radiography  

International Nuclear Information System (INIS)

Our objective was to evaluate interobserver agreement and to compare the performance score in quality control of screen-film mammography and computed radiography (CR) using a breast phantom. Eleven radiologists interpreted a breast phantom image (CIRS model X) by four viewing methods: (a) original screen-film; (b) soft-copy reading of the digitized film image; (c) hard-copy reading of CR using an imaging plate; and (d) soft-copy reading of CR. For the soft-copy reading, a 17-in. CRT monitor (1024 x 1536 x 8 bits) was used. The phantom image was evaluated using a scoring system outlined in the instruction manual, and observers judged each object using a three-point rating scale: (a) clearly seen; (b) barely seen; and (c) not seen. For statistical analysis, the kappa statistic was employed. For ''mass'' depiction, interobserver agreement using CR was significantly lower than when using screen-film (p<0.05). There was no significant difference in the kappa value for detecting ''microcalcification''; however, the performance score of ''microcalcification'' on CR hard-copy was significantly lower than on the other three viewing methods (p<0.05). Viewing methods (film or CR, soft-copy or hard-copy) could affect how the phantom image is judged. Paying special attention to viewing conditions is recommended for quality control of CR mammograms. (orig.)

159

Comparison of survey radiography with ultrasonography and x-ray computed tomography for clinical staging of subcutaneous neoplasms in dogs  

International Nuclear Information System (INIS)

A study of 26 dogs (examined consecutively) with infiltrative subcutaneous neoplasms (mastocytoma, n = 11; soft tissue sarcoma, n = 13; and adenocarcinoma, n = 2) was conducted. Dogs were evaluated by physical examination, survey radiography, ultrasonography (US), and x-ray computed tomography (CT) prior to surgical excision of the tumor. The purpose of the evaluation was to accurately define gross neoplastic margins before surgical excision and to determine whether a difference could be observed between routine clinical staging (physical examination and survey radiography) and more detailed clinical staging (US and CT imaging). The clinical stage of 5 of 26 neoplasms assessed by US and of 17 of 26 neoplasms assessed by CT was determined to be more advanced because of previously undetected neoplasia, greater neoplastic size, or greater tissue invasiveness. Preoperative imaging of infiltrative subcutaneous neoplasms, using US and CT, is highly recommended to accurately determine gross neoplastic margins

160

Use of a digitally reconstructed radiograph-based computer simulation for the optimisation of chest radiographic techniques for computed radiography imaging systems  

Science.gov (United States)

Objectives The purpose of this study was to derive an optimum radiographic technique for computed radiography (CR) chest imaging using a digitally reconstructed radiograph computer simulator. The simulator is capable of producing CR chest radiographs of adults with various tube potentials, receptor doses and scatter rejection. Methods Four experienced image evaluators graded images of average and obese adult patients at different potentials (average-sized, n=50; obese, n=20), receptor doses (n=10) and scatter rejection techniques (average-sized, n=20; obese, n=20). The quality of the images was evaluated using visually graded analysis. The influence of rib contrast was also assessed. Results For average-sized patients, image quality improved when tube potential was reduced compared with the reference (102 kVp). No scatter rejection was indicated. For obese patients, it has been shown that an antiscatter grid is indicated, and should be used in conjunction with as low a tube potential as possible (while allowing exposure times kerma by 50% without adversely influencing image quality. Rib contrast did not interfere at any tube potential. Conclusions A virtual clinical trial has been performed with simulated chest CR images. Results indicate that low tube potentials (<102 kVp) are optimal for average and obese adults, the former acquired without scatter rejection, the latter with an anti-scatter grid. Lower receptor (and therefore patient doses) than those used clinically are possible while maintaining adequate image quality. PMID:22253349

Moore, C S; Avery, G; Balcam, S; Needler, L; Swift, A; Beavis, A W; Saunderson, J R

2012-01-01

 
 
 
 
161

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

International Nuclear Information System (INIS)

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

162

Non-destructive analysis of rape plant pod by neutron radiography  

International Nuclear Information System (INIS)

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)

163

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

International Nuclear Information System (INIS)

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.

164

The clinical significance of Fuji computed radiography on lateral chest radiogram  

International Nuclear Information System (INIS)

The purpose of this study was to clarify the benefits of digital lateral chest radiogram. In the basic study, the modulation transfer factor (MTF) and the wiener spectra (WS) of conventional screen film (CSF) and Fuji computed radiography (FCR) were measured. The visibility of the simulated nodules on FCR using 3 human bodies was subjectively compared with that on CSF by 13 observers. In the clinical study, the visibility of the normal structures on FCR was subjectively compared with that on CSF using 50 lateral chest radiograms by 10 observers. The diagnostic performance to detect pulmonary nodules on FCR was also compared with that on CSF using each 30 positive and negative cases by 8 observers. In the basic study, the MTF of FCR was superior to that of CSF, and the WS of FCR displayed in half size was superior to that of CSF. In all exposure conditions, the visibility of the nodules on FCR in the pulmonary apex was inferior to that on CSF, while FCR was superior to CSF in the other lung field. However, the visibility of the nodules on FCR in the pulmonary apex was improved when the exposure condition was increased. In the clinical study, the visibility of the normal structures on FCR was comparable or superior to that on CSF except for interlobar fissure due to resolution properties. The diagnostic performance of pulmonary nodules on FCR was comparable to that on CSF especially in classifying the marginal character and diameter of the nodules. According to the location of the nodules, the detectability of FCR was superior to that of CSF in the retrosternal space and tended to be inferior to that of CSF in the pulmonary apex. An adequate exposure condition should be considered before discussing the visibility and detectability of abnormal shadow in the lateral chest radiogram. In conclusion, the digital lateral chest radiogram is superior to the CSF images, mainly because of wide latitude in FCR. (author)

165

Experimental investigation of a computed radiography system as detector for dosimetry  

International Nuclear Information System (INIS)

Several techniques have been developed for detecting radiation. However, very few have been established for detecting a radiation image two-dimensionally. The most widely used technique in this area is photo film. The advantages of the computed radiography (CR) systems become clear when they are compared with photo films or other radiation image sensors. They offer an ultrahigh sensitivity and can be used in a much larger dose range. One distinct advantage of the CR systems is that they have a higher spatial resolution. Depending on the purpose, the reading density with a CR plate can be selected from 5 to 40 pixels/mm. This feature particularly makes the CR plate a very useful tool in the area of dosimetry; especially when it comes to investigate small and irregular fields. A comparative study of CR plates with ion chambers shows that the ion chambers clearly underestimate the output factors of small beams, whereas CR plates shows flatter profiles, sharper resolution and better accuracy in critical flatness and penumbra measurements. The aim of this work is to optimize the accuracy of the CR system as a dosimetric device. This includes the evaluation of various tests and Monte Carlo simulations. A KODAK ACR-2000i system was used in this study. It comprised a laser scanner connected to a PC and Kodak CR plates. The photon radiation used for these investigations was provided by the 60Co unit available at PTB. The CR plates were placed in a PMMA (polymethylmethacrylat) phantom at a depth of 5 cm and irradiated with a 10 cm X 10 cm field at a 100 cm source-surface distance

166

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

International Nuclear Information System (INIS)

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

167

Comparison of digital radiography and dual-sided reading of computed radiography system for imaging quality and radiation dose  

International Nuclear Information System (INIS)

Objective: To compare imaging quality and radiation dose on DR and dual-sided reading of CR system. Methods: The TRG of ALVIM statistics phantom was exposed by DR and dual-sided reading of CR with the same radiation dose, then the exposure factor and the entrance surface dose (ESD) were recorded. After that, the phantom was exposed by dual-sided reading of CR with various mAs ( 3.2, 4.0, 4.3, 4.8 and 5.2 mAs) and the same kV, and the ESD was recorded, too. The acquired images were read by three radiologists on the monitor of diagnosis work station with the same window width and window level, then the total points of the images were given with the method of a five-level confidence scale. ROC curves were drawn and probability Pdet was calculated. Then the data was analyzed statistically by analysis of variance (ANOVA). Results: The ROC analysis of bone substitute with diameter from 0.5 to 1.0 mm and muscle substitute with diameter from 0.9 to 2.0 mm showed A(z) values of 0.742 to 0.923 and 0.635 to 0.900 for DR system when the radiation dose was 137.5 ?Gy. The ROC analysis of bone substitute and muscle substitute showed A (z) values of 0.526 to 0.586 and 0.473 to 0.560 for dual-sided reading of CR at the same radiation dose. The probability Pdet discrepancy of bone substitute in two systems was from 0.216 to 0.337, with the highest of 0.337 in the diameter of 1.0 mm. The probability Pdet, discrepancy by muscle substitute in two systems was from 0.075 to 0.342, with the highest of 0.342 in the diameter of 2.0 mm. There was significant statistical difference between the two groups (F=35.30, Pdet, discrepancy of bone substitute in two systems was from -0.003 to 0.009. The probability Pdet, discrepancy of muscle substitute in two systems was from -0.005 to 0.008, and there was no statistical difference between the two groups (F=5.23, P> 0.05). When the probability Pdet of two systems was the same, the ESD was 180.4 ?Gy by dual-sided reading of CR system, and the ESD was 137.5 ?Gy by DR system. Conclusion: Detection with DR system was proved to be superior to dual-sided reading of CR system at the same radiation dose. When the image quality was similar, the radiation dose of DR system was less than the dual-sided reading of CR system. (authors)

168

Digital real time radiography and X-ray computed tomography development at AWE plc  

International Nuclear Information System (INIS)

Digital X-ray imaging promises many advantages over conventional film radiography. The technique collects images electronically thus eliminating X-ray film, chemicals and chemical waste. Many radiographs can be stored on an optical disk or CD ROM and can be retrieved quickly and repeatedly using modern data archiving methods. Data can be transmitted electronically over local networks or the Internet for remote consultations. This paper discusses the development of a lens coupled digital radiography system currently being developed at AWE plc to examine high-density weapon components and sub-assemblies

169

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

Energy Technology Data Exchange (ETDEWEB)

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 exposure. If similar TCT findings observed in such patients, treatment for tuberculosis should be considered.

Uzum, Kazim; Karahan, Okkes I.; Dogan, Sukru; Coskun, Abdulhakim E-mail: coskuna@erciyes.edu.tr; Topcu, Faik

2003-12-01

170

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

Science.gov (United States)

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 pCT images of a cylindrical phantom containing inserts of different materials. As for all conventional pCT systems, the method illustrated in this work produces tomographic images that are potentially more accurate than x-ray CT in providing maps of proton relative stopping power (RSP) in the patient without the need for converting x-ray Hounsfield units to proton RSP. All phantom tests produced reasonable results, given the currently limited spatial and time resolution of the prototype detector. The dose required to produce one radiographic image, with the current settings, is ˜0.7 cGy. Finally, we discuss a series of techniques to improve the resolution and accuracy of radiographic and tomographic images for the future development of a full-scale detector.

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

2013-11-01

171

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

Science.gov (United States)

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 pCT images of a cylindrical phantom containing inserts of different materials. As for all conventional pCT systems, the method illustrated in this work produces tomographic images that are potentially more accurate than x-ray CT in providing maps of proton relative stopping power (RSP) in the patient without the need for converting x-ray Hounsfield units to proton RSP. All phantom tests produced reasonable results, given the currently limited spatial and time resolution of the prototype detector. The dose required to produce one radiographic image, with the current settings, is ~0.7 cGy. Finally, we discuss a series of techniques to improve the resolution and accuracy of radiographic and tomographic images for the future development of a full-scale detector. PMID:24200989

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

2013-11-21

172

Schemes for the optimization of chest radiography using a computer model of the patient and x-ray imaging system  

International Nuclear Information System (INIS)

A computer program has been developed to model chest radiography. It incorporates a voxel phantom of an adult and includes antiscatter grid, radiographic screen, and film. Image quality is quantified by calculating the contrast (?OD) and the ideal observer signal-to-noise ratio (SNRI) for a number of relevant anatomical details at various positions in the anatomy. Detector noise and system unsharpness are modeled and their influence on image quality is considered. A measure of useful dynamic range is computed and defined as the fraction of the image that is reproduced at an optical density such that the film gradient exceeds a preset value. The effective dose is used as a measure of the radiation risk for the patient. A novel approach to patient dose and image quality optimization has been developed and implemented. It is based on a reference system acknowledged to yield acceptable image quality in a clinical trial. Two optimizations schemes have been studied, the first including the contrast of vessels as measure of image quality and the second scheme using also the signal-to-noise ratio of calcifications. Both schemes make use of our measure of useful dynamic range as a key quantity. A large variety of imaging conditions was simulated by varying the tube voltage, antiscatter device, screen-film system, and maximum optical density in the computed image. It was found that the optical density is crucial in screen-film chest radiography. Significant dose savm chest radiography. Significant dose savings (30%-50%) can be accomplished without sacrificing image quality by using low-atomic-number grids with a low grid ratio or an air gap and more sensitive screen-film system. Dose-efficient configurations proposed by the model agree well with the example of good radiographic technique suggested by the European Commission

173

Gamma radiography and its technological application  

International Nuclear Information System (INIS)

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.)

174

PyRAT (python radiography analysis tool): overview  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2011-01-14

175

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

International Nuclear Information System (INIS)

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

176

Computed Tomography and Computed Radiography of late Bronze Age Cremation Urns from Denmark : An interdisciplinary attempt to develop methods applied in Bioarchaeological cremation research  

DEFF Research Database (Denmark)

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 intensity show markedly poorer preservation and recovery than white calcined fragments do. Thus post-excavation estimations of cremation intensity are systematically biased

Harvig, Lise Lock; Lynnerup, Niels

2012-01-01

177

A study of tube voltage and added filter for chest x-ray using computed radiography  

International Nuclear Information System (INIS)

Images with reduced rib shadows can be obtained on chest radiography by using a higher voltage or applying an additional filter, owing to an increase in effective energy. Although images with poor discriminative ability result from radiography at a high effective energy level when screen/film systems are used, a result of a general decrease in the contrast of the subject, shadows of soft tissues are apparently emphasized when the CR system is used. Because tone is adjusted according to the width of the histogram by the exposure-data-recognizer (EDR) mechanism, a higher effective energy level is expected to be advantageous in chest radiography using the CR system. As long as the incident dose to the imaging plate (IP) is maintained at a nearly fixed level using a phototimer, EDR-enhanced noise, soft tissue signals, and the SNR in the lung field are reduced, with an increase in effective energy. All in all, the high effective energy technique has reduced the ability to diagnose low contrast masses. Increasing the dose is extremely efficient in the high SNR of the lung field and maintains the advantage of high-voltage radiography in the CR system using the EDR mechanism. The increase ratio requisite for exposure is about 1.4 in Cu 0.1 mm+Al 2 mm, about 1.6 in Cu 0.3 mm using 141 kV, with the proviso that the increase ratio is 1.0 when the sensitivity of the phototimer is normal. (author)

178

Transition to computed radiography: can emergency medicine doctors accurately predict the need of film printing to facilitate optimal patient care?  

Science.gov (United States)

BACKGROUND: This study aimed to evaluate emergency medicine doctors’ accuracy in predicting the need of film printing in a simulated setting of computed radiography and assess whether this can facilitate optimal patient care. METHODS: Cross sectional study was conducted from 20 March 2009 to 3 April 2009 in 1334 patients. After clinical assessment of those patients who needed X-ray examination, doctors in the emergency department would indicate whether film printing was necessary for subsequent patient care in a simulated computed radiography setting. The final discharge plan was then retrieved from each patient record. Accuracy of doctors’ prediction was calculated by comparing the initial request for radiographic film printing and the final need of film. Doctors with different level of emergency medicine experience would also be analyzed and compared. RESULTS: The sensitivity of predicting film printing was 84.5% and the specificity of predicting no film printing was 91.2%. Positive predictive value was 88.4% while negative predictive value was 88.2%. The overall accuracy was 88.2%. The accuracy of doctors stratified into groups of fellows, higher trainees and basic trainees were 85.4%, 90.5% and 88.5% respectively (P=0.073). CONCLUSIONS: Our study showed that doctors can reliably predict whether film printing is needed after clinical assessment of patients, before actual image viewing. Advanced indication for film printing at the time of imaging request for selected patients can save time for all parties with minimal wastage.

Yang, Siu Ming; Lo, Chor Man

2011-01-01

179

Comparison of an amorphous silicon/cesium iodide flat-panel digital chest radiography system with screen/film and computed radiography systems - A contrast-detail phantom study  

International Nuclear Information System (INIS)

Flat-panel (FP) based digital radiography systems have recently been introduced as a new and improved digital radiography technology; it is important to evaluate and compare this new technology with currently widely used conventional screen/film (SF) and computed radiography (CR) techniques. In this study, the low-contrast performance of an amorphous silicon/cesium iodide (aSi/CsI)-based flat-panel digital chest radiography system is compared to those of a screen/film and a computed radiography system by measuring their contrast-detail curves. Also studied were the effects of image enhancement in printing the digital images and dependence on kVp and incident exposure. It was found that the FP system demonstrated significantly better low-contrast performance than the SF or CR systems. It was estimated that a dose savings of 70%-90% could be achieved to match the low-contrast performance of the FP images to that of the SF images. This dose saving was also found to increase with the object size. No significant difference was observed in low-contrast performances between the SF and CR systems. The use of clinical enhancement protocols for printing digital images was found to be essential and result in better low-contrast performance. No significant effects were observed for different kVps. From the results of this contrast-detail phantom study, the aSi/CsI-based flat-panel digital chest system should perform better under clinical situations for detection of low-contrast objects such as lung nodules. However, proper processing prior to printing would be essential to realizing this better performance

180

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

International Nuclear Information System (INIS)

inical 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

 
 
 
 
181

Effect of x-ray tube potential on image quality and patient dose for lumbar spine computed radiography examinations.  

Science.gov (United States)

A study was conducted to investigate the effect of increasing x-ray tube voltage on patient dose and image quality during computed radiography (CR) examination of the lumbar spine. Images of a pelvis - lumbar spine phantom were obtained at three different tube voltages using two CR systems. The images were evaluated by image scores (IS) using the image quality criteria proposed by the Commission of the European Communities (CEC), by measuring the signal-to-noise ratio and the contrast-to-noise ratio. The entrance surface dose (ESD) to the phantom was also measured using ionisation chambers and the resulting gonad dose (G) and effective dose (E) were calculated. The CEC recommended tube voltages can be exceeded with CR systems for lumbar spine radiography. The ESD, G and E decreased by 25%-50% with both CR systems when tube voltage was increased. Although the decrease in IS was statistically significant (P < 0.05) the images obtained with the 3 tube voltages were diagnostically acceptable. The balance between image quality and patient dose can be optimised by using higher x-ray tube voltages for lumbar spine CR examinations. PMID:16506618

Brindhaban, A; Al Khalifah, K; Al Wathiqi, G; Al Ostath, H

2005-12-01

182

Computed tomography and conventional radiography in intrathoracic metastases from non-seminomatous testicular tumor  

International Nuclear Information System (INIS)

Conventional chest radiographs and CT scans were studied retrospectively in 283 patients with untreated non-seminomatous testicular tumor. Intrathoracic metastases were found in 47 patients, and CT was the only positive examination in 20 of them. Lung metastases were seen in 39 patients and mediastinal lymph nodes were involved in 13. The additional yield of CT in detecting metastases was most marked for the lymph nodes (tumor detected only at CT in 9 out of 13 cases as compared with 14 out of 39 for the lung parenchyma). Posterior mediastinal and retrocrural lymph nodes were most often enlarged, and involvement of these was most difficult to detect at conventional radiography. (orig.)

183

Quality comparison between DEF-10 digital image from simulation technique and Computed Tomography (CR) technique in industrial radiography  

International Nuclear Information System (INIS)

The study was conducted to make comparison of digital image quality of DEF-10 from the techniques of simulation and computed radiography (CR). The sample used is steel DEF-10 with thickness of 15.28 mm. In this study, the sample is exposed to radiation from X-ray machine (ISOVOLT Titan E) with certain parameters. The parameters used in this study such as current, volt, exposure time and distance are specified. The current and distance of 3 mA and 700 mm respectively are specified while the applied voltage varies at 140, 160, 180 and 200 kV. The exposure time is reduced at a rate of 0, 20, 40, 60 and 80 % for each sample exposure. Digital image of simulation produced from aRTist software whereas digital image of computed radiography produced from imaging plate. Therefore, both images were compared qualitatively (sensitivity) and quantitatively (Signal to-Noise Ratio; SNR, Basic Spatial Resolution; SRb and LOP size) using Isee software. Radiographic sensitivity is indicated by Image Quality Indicator (IQI) which is the ability of the CR system and aRTist software to identify IQI of wire type when the time exposure is reduced up to 80% according to exposure chart ( D7; ISOVOLT Titan E). The image of the thinnest wire diameter achieved by radiograph from simulation and CR are the wire numbered 7 rather than the wire numbered 8 required by the standard. In quantitative comparison, this study shows that the SNR values decreases with reducing exposure time. SRb values increases for simulation and decreases for CR when the exposure time decreases and the good image quality can be achieved at 80% reduced exposure time. The high SNR and SRb values produced good image quality in CR and simulation techniques respectively. (author)

184

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  

International Nuclear Information System (INIS)

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

185

Demonstration of the metastatic pulmonary nodules by Fuji Computed Radiography (FCR)  

International Nuclear Information System (INIS)

Twenty one examinations of chest FCR were performed in 15 malignancies with pulmonary metastases. The rate for demonstrating, less than 5, from 5 to 15, and more than 15 mm pulmonary nodules using with FCR was retrospectively evaluated on the basis of the lesions detected with CT. The demonstrating rate for pulmonary nodules less than 5 mm in diameter was only 8 % ; for 5 - 15 mm nodules, about 87 %. However, several 5 - 15 mm nodules were not demonstrated due to overlap of the pulmonary vessels and bony structures. All nodules more than 15 mm were demonstrable. Chest FCR may demonstrate more pulmonary nodules than conventional radiography. However, the further studies should be required for the improvement of detectability of them with FCR. (author)

186

Optimization of digital chest radiography using computer modeling and voxels phantoms  

International Nuclear Information System (INIS)

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 ?Gy) 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)

187

The Study of real-time radiography system based on array absorption-emission computed tomography  

International Nuclear Information System (INIS)

By the comprehensive analysis of existing measuring methods, a new method is proposed to measure the nuclear radiation dose field with array absorption-emission computed tomography. The detector based on scintillation optical fiber array and its servo- control system are designed. The weak optical signal is measured by Charge Coupled Devices (CCD) and the formed visual signal is quickly sampled with the method of testing fixed signed points. The reconstruction method of iterative filter back projection and the data renovate based on non-complete projection are proposed to reconstruct dose field more accurately. The filter function is also an important factor in the image reconstruction. The Butter worth filter function is chosen. By adjusting its parameters, the authors have obtained optimum result. Finally, all the experimentation shows that the methods proposed are proper and whole measuring system is advanced and feasible

188

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

International Nuclear Information System (INIS)

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 rhion 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)

189

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

1988-01-01

190

Comparative study by computed radiography, histology, and scanning electron microscopy of the articular cartilage of normal goats and in chronic infection with caprine arthritis-encephalitis virus.  

Science.gov (United States)

In the northeast of Brazil, caprine arthritis-encephalitis (CAE) is one of the key reasons for herd productivity decreasing that result in considerable economic losses. A comparative study was carried out using computed radiography (CR), histological analysis (HA), and scanning electronic microscopy (SEM) of the joints of CAE infected and normal goats. Humerus head surface of positive animals presented reduced joint space, increased bone density, and signs of degenerative joint disease (DJD). The carpal joint presented no morphological alterations in CR in any of the animals studied. Tarsus joint was the most affected, characterized by severe DJD, absence of joint space, increased periarticular soft tissue density, edema, and bone sclerosis. Histological analysis showed chronic tissue lesions, complete loss of the surface zone, absence of proteoglycans in the transition and radial zones and destruction of the cartilage surface in the CAE positive animals. Analysis by SEM showed ulcerated lesions with irregular and folded patterns on the joint surface that distinguished the limits between areas of normal and affected cartilage. The morphological study of the joints of normal and CAE positive goats deepened understanding of the alteration in the tissue bioarchitecture of the most affected joints. The SEM finding sustained previous histological reports, similar to those found for rheumatoid arthritis, suggesting that the goat infected with CAE can be considered as a potential model for research in this area. PMID:24190602

de Sousa, Videlina Rodrigues; das Chagas Araújo Sousa, Francisco; da Silva Filho, Osmar Ferreira; Grassi Rici, Rose Eli; das Neves Diniz, Anaemilia; da Silva Moura, Laécio; de Jesus Rosa Pereira Alves, Jacyara; de Sousa Júnior, Antônio; Angélica Miglino, Maria; de Sousa, João Macedo; de Jesus Moraes Junior, Felipe; Ribeiro Alves, Flávio

2014-01-01

191

Comparison of magnetic resonance imaging, computed tomography, and radiography for assessment of noncartilaginous changes in equine metacarpophalangeal osteoarthritis.  

Science.gov (United States)

We compared the ability of 1.5 T magnetic resonance imaging (MRI), computed tomography (CT), and computed radiography (CR) to evaluate noncartilaginous structures of the equine metacarpophalangeal joint (MCP), and the association of imaging changes with gross cartilage damage in the context of osteoarthritis. Four CR projections, helical single-slice CT, and MRI (Ti-weighted gradient recalled echo [GRE], T2*-weighted GRE with fast imaging employing steady-state acquisition [FIESTA], T2-weighted fast spin echo with fat saturation, and spoiled gradient recalled echo with fat saturation ISPGR-FS]) were performed on 20 racehorse cadaver forelimbs. Osteophytosis, synovial effusion, subchondral bone lysis and sclerosis, supracondylar lysis, joint fragments, bone marrow lesions, and collateral desmopathy were assessed with each modality. Interexaminer agreement was inferior to intraexaminer agreement and was generally moderate (i.e., 0.4 bone sclerosis scores using CT or MRI were correlated significantly with the reference quantitative CT technique used to assess bone mineral density (P < 0.0001). Scores for subchondral lysis and osteophytosis were higher with MRI or CT vs. CR (P < 0.0001). Although differences between modalities were noted, osteophytosis, subchondral sclerosis, and lysis as well as synovial effusion were all associated with the degree of cartilage damage and should be further evaluated as potential criteria to be included in a whole-organ scoring system. This study highlights the capacity of MRI to evaluate noncartilaginous changes in the osteoarthritic equine MCP joint. PMID:20469548

Olive, Julien; D'Anjou, Marc-André; Alexander, Kate; Laverty, Sheila; Theoret, Christine

2010-01-01

192

Colour radiography  

International Nuclear Information System (INIS)

The advantage and general state of colour radiography used for flaw detection of metallic articles are discussed. Direct and indirect methods of getting colour radiographs are described. Short characteristics of foreign colour films ''Ectacolour print'', ''Etachrom'', ''Orvocolour RS-7'' and experimental home-made colour film RTS-1 are given. As experience has shown the colour radiography has higher reliability of flaw detection in comparison with the routine radiography. The colour radiographic method gives considerable advantages when controlling objects of complex configuration with wide thickness and density range of separate elements. It also reduces fatigability of people deciphing the films

193

Anthropomorphic chest phantom imaging – The potential for dose creep in computed radiography  

International Nuclear Information System (INIS)

For film-based radiography the operator had to be exact in the selection of acquisition parameters or the image could easily become under- or over-exposed. By contrast, digital technology allows for a much greater tolerance of acquisition factor selection which would still give an image of acceptable diagnostic quality. In turn this greater tolerance allows for the operator to increase effective dose for little or no penalty in image quality. The purpose of this article is to determine how image quality and lesion visibility vary with effective dose (E) in order to identify how much overexposure could be tolerated within the radiograph. Using an anthropomorphic chest phantom with ground glass lesions we determined how perceptual image quality and E varied over a wide range of acquisition conditions. Perceptual image quality comprised of image quality and lesion visibility. E was calculated using Monte Carlo method; image quality was determined using a two alternative forced choice (2AFC) method and the quality criteria were partly informed from European guidelines. Five clinicians with significant experience in image reading scored the images for quality (intraclass correlation coefficient 0.869). Image quality and lesion visibility had a close correlation (R2 > 0.8). The tolerance for over-exposure, whilst still acquiring an image of acceptable quality, increases with decreasing kV and increasing source to image distance (SID). The maximum over-exposure factor (ratio of maximum E to minimum E that produce images of acceptable quality) possible was 139 (at 125 cm and 60 kV). Given the phantom had characteristics similar to the human thorax we propose that that potential for overexposure in a human whilst still obtaining an image of acceptable perceptual image quality is very high. Further research into overexposure tolerance and dose creep should be undertaken

194

Design of Mega-Voltage X-ray Digital Radiography and Computed Tomography Performance Phantoms  

Energy Technology Data Exchange (ETDEWEB)

A number of fundamental scientific questions have arisen concerning the operation of high-energy DR and CT systems. Some of these questions include: (1) How deeply can such systems penetrate thickly shielded objects? (2) How well can such systems distinguish between dense and relatively high Z materials such as lead, tungsten and depleted uranium and lower Z materials such as steel, copper and tin? (3) How well will such systems operate for a uranium material which is an intermediate case between low density yellowcake and high density depleted uranium metal? These questions have led us to develop a set of phantoms to help answer these questions, but do not have any direct bearing on any smuggling concern. These new phantoms are designed to allow a systemic exploration of these questions by gradually varying their compositions and thicknesses. These phantoms are also good probes of the blurring behavior of radiography and tomography systems. These phantoms are composed of steel ({rho} assumed to be 7.8 g/cc), lead ({rho} assumed to be 11.4 g/cc), tungsten ({rho} assumed to be 19.25 g/cc), uranium oxide (UO{sub 3}) ({rho} assumed to be 4.6 g/cc), and depleted uranium (DU) ({rho} assumed to be 18.9 g/cc). There are five designed phantoms described in this report: (1) Cylindrical shells of Tungsten and Steel; (2) Depleted Uranium Inside Tungsten Hemi-cube Shells; (3) Nested Spherical Shells; (4) UO{sub 3} Cylinder; and (5) Shielded DU Sphere.

Aufderheide, M B; Martz, H E; Curtin, M

2009-06-22

195

Computer aided safety analysis  

International Nuclear Information System (INIS)

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

196

Accuracy of periapical radiography, panoramic radiography and computed tomography for examining the mental foramen region / Acurácia de radiografia periapical, radiografia panorâmica e tomografia computadorizada para exame da região do forame mentual  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese OBJETIVO: Determinar a acurácia de diferentes métodos radiográficos para estimação de altura óssea na região do forame mentual. METODOLOGIA: Vinte hemi-mandíbulas humanas, secas, foram examinadas por radiografia periapical e panorâmica e tomografia computadorizada. Um paquímetro digital foi usado pa [...] ra medir os traçados obtidos das radiografias em três diferentes tempos (grupos A1, A2 e A3) e nas hemi-mandíbulas seccionadas transversalmente (grupo B). As medições foram: Medida 1 - do limite superior da crista óssea ao limite superior do forame mentual; Medida 2 - do limite superior do forame mentual ao limite inferior do osso cortical da base da mandíbula; Medida 3 - do limite superior da crista óssea ao limite inferior do osso cortical da base da mandíbula. Os dados foram analisados por teste t de Student e teste de Friedman. RESULTADOS: Os valores médios de diferença na Medida 1 foram 0,33 mm, 0,35 mm e 0,85 mm para a radiografia periapical, tomografia computadorizada e radiografia panorâmica, respectivamente (intervalos de confiança de 0,17 a 0,49 mm, 0,18 a 0,53 mm e 0,38 a 1,32 mm, respectivamente). As radiografias panorâmicas mostraram as maiores diferenças nas Medidas 2 e 3, com valores médios de 1,05 mm e 1,93 mm, respectivamente. CONCLUSÃO: A radiografia periapical e a tomografia computadorizada mostraram a melhor acurácia. Sugere-se uma margem de segurança em caso de cirurgias. Abstract in english PURPOSE: To determine the accuracy of different radiographic methods for bone height estimation at the mental foramen area. METHODS: Twenty dry human hemimandibles were examed by using periapical and panoramic radiography, and computed tomography. An electronic digital caliper was used to measure th [...] e tracings obtained from the radiographies in three different times (groups A1, A2 and A3) and in the cross-sectioned hemimandibles (group B). Measurements consisted of: Measure 1 - from the upper limit of the alveolar ridge to the upper limit of the mental foramen; Measure 2 - from the upper limit of the mental foramen to the inferior limit of the cortical bone of the base of the jaw; Measure 3 - from the upper limit of the alveolar ridge to the inferior limit of the cortical bone of the base of the jaw. Data were analyzed with Student-t and Friedman tests. RESULTS: The average difference values in Measure 1 were 0.33 mm, 0.35 mm and 0.85 mm for the periapical radiography, computed tomography and panoramic radiography, respectively (confidence intervals of 0.17 mm to 0.49 mm, 0.18 mm to 0.53 mm and 0.38 mm to 1.32 mm, respectively). Panoramic radiographies showed the greatest differences in Measures 2 and 3, with average values of 1.05 mm and 1.93 mm, respectively. CONCLUSION: Periapical radiography and computed tomography showed the best accuracy. A safety margin for surgical purposes has been suggested.

Alexandre, Bahlis; Luis André, Mezzomo; Daniel, Boeckel; Nilza Pereira da, Costa; Eduardo Rolim, Teixeira.

197

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

Science.gov (United States)

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

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

2013-07-01

198

Retrospective patient dose analysis of a digital radiography system in routine clinical use  

International Nuclear Information System (INIS)

The log files generated in the flat-panel detector based digital radiography systems (Philips Digital Diagnost) at 11 different hospitals were used to acquire data regarding the dose-area product (DAP) and the entrance air kerma (EAK) for all X-ray examinations performed in routine clinical use. A retrospective statistical analysis of the data with respect to the dose levels was performed for several examination types. The resulting average dose levels were compared with the diagnostic reference levels (DRLs). While for the same type of examination the median dose level at different hospitals could differ by up to a factor of 5, almost all the dose levels were found to be much below the published DRL. Only in one hospital for one type of examination (Thorax PA) the DRL for the DAP was slightly exceeded, while for the same site and examination the EAK was still below the DRL. In conclusion, examination log files can be used for retrospective dose analysis and correlation with DRLs. (authors)

199

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

International Nuclear Information System (INIS)

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

200

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

Science.gov (United States)

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 pulmonary congestion through the evaluation of vertical reverberation artifacts, known as B-lines. These artifacts are related to multiple minimal acoustic interfaces between small water-rich structures and alveolar air, as it happens in case of thickened interlobular septa due to increase of extravascular lung water. The number, diffusion and intensity of B lines correlates with both the radiologic and invasive estimate of extravascular lung water. The integration of conventional chest radiograph with LUS can be very helpful to obtain the correct diagnosis. Computed tomography (CT) is of limited use in the work up of cardiogenic pulmonary edema, due to its high cost, little use in the emergencies and radiation exposure. However, a deep knowledge of CT signs of pulmonary edema is crucial when other similar pulmonary conditions may occasionally be in the differential diagnosis. PMID:24976926

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

2014-01-01

 
 
 
 
201

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

Science.gov (United States)

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 pulmonary congestion through the evaluation of vertical reverberation artifacts, known as B-lines. These artifacts are related to multiple minimal acoustic interfaces between small water-rich structures and alveolar air, as it happens in case of thickened interlobular septa due to increase of extravascular lung water. The number, diffusion and intensity of B lines correlates with both the radiologic and invasive estimate of extravascular lung water. The integration of conventional chest radiograph with LUS can be very helpful to obtain the correct diagnosis. Computed tomography (CT) is of limited use in the work up of cardiogenic pulmonary edema, due to its high cost, little use in the emergencies and radiation exposure. However, a deep knowledge of CT signs of pulmonary edema is crucial when other similar pulmonary conditions may occasionally be in the differential diagnosis. PMID:24976926

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

2014-06-28

202

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

Energy Technology Data Exchange (ETDEWEB)

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).

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

1995-11-01

203

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

International Nuclear Information System (INIS)

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)

204

Implementation of an HL7/DICOM broker for automated patient demographic data entry in computed radiography systems  

Science.gov (United States)

As radiology departments move closer to enterprise-wide electronic imaging systems, the importance of timely and accurate patient and exam information cannot be overstated. In addition, automated entry of patient and exam information into image acquisition modalities (e.g., computed radiography, CR) enhances technologist productivity, which is critical in high volume practices (e.g. a major trauma center). A difficulty arises, however, since the authoritative source of patient and exam information may be a Radiology Information System (RIS) or a Hospital Information System (HIS) packages its data differently than most imaging modalities. To bridge this gap, we have implemented an interface engine to affect the translation of Health Level Seven (HL7) messages from the RIS (or HIS) into Digital Imaging Communications In Medicine (DICOM) messages for seven CR systems (Fuji Medical Systems, Burbank, CA). Recent measurements suggest that manual technologist transcription of information into the CR unit takes 45.4 plus or minus 3.0 seconds. Since the introduction of the HL7/DICOM broker, the time has dropped to 5.4 plus or minus 0.1 seconds to produce the same information.

Langer, Steven G.; Stewart, Brent K.

1998-07-01

205

Industrial radiography  

International Nuclear Information System (INIS)

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

206

Electron paramagnetic resonance study of a Eu2+ related defect in CsBr:Eu needle image plates for computed radiography.  

Science.gov (United States)

The electron paramagnetic resonance (EPR) spectrum of needle image plates of CsBr doped with Eu(2+), which are proposed as new X-ray storage phosphors for computed radiography, is studied at room temperature and Q-band microwave frequencies (34 GHz). X-ray diffraction analysis demonstrates that the CsBr:Eu(2+) needles have an 001 out of plane (perpendicular to the plate) orientation, and contrary to expectation that the in plane orientation is not random. The room temperature EPR spectrum is attributed to a single centre which is related to Eu(2+) with axial 001 symmetry. Using the spin Hamiltonian parameters extracted from the spectrum recorded with the magnetic field parallel to the needles' axes, we convincingly simulate both the spectrum of a powdered image plate and the single crystal like angular dependence of intact pieces of image plate. The knowledge of the symmetry of this centre, which appears to be related with the radiation sensitivity of the plate, presents a first step in finding its model and role in the X-ray storage process. PMID:17997351

Loncke, F; Vrielinck, H; Matthys, P; Callens, F; Tahon, J P; Leblans, P

2008-05-01

207

Evaluation of the diagnostic value of a computed radiography system by comparison of digital hard copy images with screen-film mammography: results of a prospective clinical trial  

International Nuclear Information System (INIS)

The purpose of the study was to determine prospectively the diagnostic value of a computed radiography (CR) system by comparing mammographic hard copy images with screen-film mammography (SFM). A series of 100 patients, who came for diagnostic investigation, underwent two-view SFM (Lorad M-IV Platinum) and digital mammography with a CR system (AGFA CR system). The images were obtained by double exposure, i.e. same view without removing compression of the corresponding breast. The CR images were processed with dedicated processing for mammography. Six radiologists read sets of SFM and CR images. The primary efficacy parameter was the overall diagnostic value. The secondary efficacy parameters were lesion conspicuity and lesion details (for masses and micro-calcifications), tissue visibility at chest wall and at skin line, axillary details, overall density and sharpness impression and the overall noise impression. These parameters were scored by a 7-point scoring system. ''CR non-inferior to SFM'' was concluded if the lower confidence interval bound exceeded 80%. The confidence interval for the overall diagnostic value was between 96.4% and 100%. Pooled analysis of the ten features for image quality comparison demonstrated for all but one feature (lesion details of the calcifications) CR non-inferiority to SFM. (orig.)

208

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

International Nuclear Information System (INIS)

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.

209

Suggested baseline ranges for performance testing of the Fujifilm FCR Capsula XL computed radiography system  

International Nuclear Information System (INIS)

Full text: Due to the difficulty in obtaining expected baseline values from the supplier for the performance testing of the Fujifilm FCR Capsula XL computed radi ography system, performance test results from the accep tance testing of 42 Capsula systems were reviewed. Guidance ranges are provided for nine system performance tests which can be applied to future testing of calibrated systems.

210

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

Science.gov (United States)

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…

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

2008-01-01

211

MTF analysis of the MURR real-time neutron radiography facility  

International Nuclear Information System (INIS)

In neutron radiography, as in other forms of NDE, it is sometimes desirable to observe dynamic events. This need has generated increased interest in real-time neutron radiography systems. As in other forms of radiography, a standard method for measuring the image forming capability of real-time systems is necessary in order to compare the various methods and systems used. A technique which has been used extensively in general photography and has been applied in the characterization of several screen-film combinations used in conventional neutron radiography is to determine the imaging system's modulation transfer function (MTF). This gives a graphical representation of the system's spatial resolution capabilities and was therefore chosen as the method for evaluation of the real-time neutron radiography facility at the University of Missouri Research Reactor (MURR). The method used was to image a knife-edge, differentiate the edge gradient to obtain the line spread function (LSF) to obtain the system MTF. A Gd foil was used for the knife-edge on several neutron converter screens and was imaged by a low-light level ISIT camera. The video signal was then digitized and presented to a PDP-11/05 microcomputer for the numerical calculations

212

X-Ray Digital Radiography and Computed Tomography Characterization of Targets  

Energy Technology Data Exchange (ETDEWEB)

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.

Sain, J D; Brown, W D; Chinn, D J; Martz Jr., H E; Morales, K E; Schneberk, D J; Updike, E O

2008-04-16

213

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

International Nuclear Information System (INIS)

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

214

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

Energy Technology Data Exchange (ETDEWEB)

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

Rivetti, S. (Dept. of Health Physics, AUSL Modena, Modena (Italy)). e-mail: nico.lanconelli@unibo.it; Canossi, B.; Battista, R.; Vetruccio, E.; Torricelli, P. (Dept. of Radiology, Univ. of Modena and Reggio Emilia, Modena (Italy)); Lanconelli, N. (Dept. of Physics, Univ. of Bologna, Bologna (Italy)); Danielli, C. (Dept. of Health Physics, Policlinico di Modena, Modena (Italy)); Borasi, G. (Dept. of Health Physics, Arcispedale Santa Maria Nuova, Reggio Emilia (Italy))

2009-12-15

215

Neutron radiography study of water absorption in porous building materials: anomalous diffusion analysis  

International Nuclear Information System (INIS)

Dynamic neutron radiography was applied to obtain the experimental data concerning the kinetics of the wetting process in two different types (fired-clay and siliceous brick) of porous construction materials. The technique provides accurate experimental data concerning the first instants as well as the advanced stages of the imbibing process. A significant difference in water absorption parameters, contrasting the materials studied, is found. Both the advance of the wetting front and the time evolution of water content distribution within the sample are analysed. It is shown that for both materials the time dependence of the wetting front position d deviates from the classical square root of time t behaviour. The deviation is analysed in terms of the intercept b in the d = a?t + b approximation and the exponent n in the power law d ? tn/2. Both materials differ in the sign of the intercept parameter: b > 0 for siliceous brick and b 1 for fired-clay brick. At the initial stages (t -n/2. The evolution of the distribution of liquid in the porous medium was analysed in terms of the anomalous diffusion equation of Kuentz and Lavallee (2001 Experimental evidence and theoretical analysis of anomalous diffusion during water infiltration in porous building materials J. Phys. D: Appl. Phys. 34 2547-54) based on the non-linear generalization of the Fick's law. This approach makes a detailed analysis of the generalized hydraulic diffusivity in the low water content region possible. Successful fitting of experimental data with the diffusivity vanishing at null water content proved the importance of the hypodiffusive component of the process

216

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  

International Nuclear Information System (INIS)

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 continued up to 1999. The primary objective was to initiate a programme of optimization of protection in diagnostic radiology in each of the participating countries by introducing quality control (QC) practices, assessment of patient doses, evaluation of image quality, and identification and implementation of corrective actions. This TECDOC may be used as an approach to optimization of radiological protection for patients in diagnostic radiology

217

Detection of simulated pulmonary nodules by single-exposure dual-energy computed radiography of the chest: effect of a computer-aided diagnosis system (Part 2)  

International Nuclear Information System (INIS)

Objective: To evaluate the performance of the computer-aided diagnosis (CAD) scheme on the detection of pulmonary nodules (PNs) in single-exposure dual-energy subtraction computed radiography (CR) images of the chest, and to evaluate the effect of this CAD scheme on radiologists' detectabilities. Methods and material: We compared the detectability by the CAD scheme with the detectability by 12 observers by using conventional CR (C-CR) and bone-subtracted CR (BS-CR) images of 25 chest phantoms with a low-contrast nylon nodule. Results: Both in the CAD scheme and for the observers, the detectability of BS-CR images was superior to that of C-CR images (P<0.005). The detection performance of the CAD scheme was equal to that of the observers. The nodules detected by the CAD did not necessarily coincide with those by the observers. Thus, if observers can use the results of the CAD system as a 'second opinion', their detectabilities increase. Conclusion: The CAD system for detection of PNs in the single-exposure dual-energy subtraction method is promising for improving radiologists' detectabilities of PNs

218

Performance evaluation of a computed radiography imaging device using a typical "front side" and novel "dual side" readout storage phosphors.  

Science.gov (United States)

The Fourier-space modulation transfer function (MTF), normalized noise power spectrum (nNPS), and detective quantum efficiency (DQE) of a computed radiography (CR) x-ray imaging device were measured. Two different storage phosphor screens were used in conjunction with a single CR reader (Fuji, Clearview, CS). One of the storage phosphor plates (ST-BD) had a clear backing material which allowed "dual side read" of the latent image from both the "front" and "back" sides of the phosphor. The other phosphor plate had a light occluding backing material, limiting the readout to front side only (ST-VI). The standard RQA-5 beam quality was used. The MTF was measured using a 1 mm thick tungsten edge device. Compared to the ST-55BD phosphor, the ST-VI phosphor was found to have modestly higher MTF at all spatial frequencies. The nNPS(f) and DQE(f) were measured for nominal incident exposure levels ranging from 0.1 to 10 mR. The dual side read phosphor demonstrated superior DQE, especially at low spatial frequencies. At the frequency 0.5 cycles/mm, the DQE values for the 1 mR exposure were 0.36 and 0.21 for the ST-55BD and ST-VI phosphor plates, respectively. The differences between the spatial-frequency dependent DQE of the two plates can be attributed to the increased signal collection efficiency of the dual side read plates and differences in storage phosphor structure noise. PMID:16532933

Fetterly, Kenneth A; Schueler, Beth A

2006-02-01

219

Performance evaluation of a computed radiography imaging device using a typical 'front side' and novel 'dual side' readout storage phosphors  

International Nuclear Information System (INIS)

The Fourier-space modulation transfer function (MTF), normalized noise power spectrum (nNPS), and detective quantum efficiency (DQE) of a computed radiography (CR) x-ray imaging device were measured. Two different storage phosphor screens were used in conjunction with a single CR reader (Fuji, Clearview, CS). One of the storage phosphor plates (ST-BD) had a clear backing material which allowed 'dual side read' of the latent image from both the 'front' and 'back' sides of the phosphor. The other phosphor plate had a light occluding backing material, limiting the readout to front side only (ST-VI). The standard RQA-5 beam quality was used. The MTF was measured using a 1 mm thick tungsten edge device. Compared to the ST-55BD phosphor, the ST-VI phosphor was found to have modestly higher MTF at all spatial frequencies. The nNPS(f) and DQE(f) were measured for nominal incident exposure levels ranging from 0.1 to 10 mR. The dual side read phosphor demonstrated superior DQE, especially at low spatial frequencies. At the frequency 0.5 cycles/mm, the DQE values for the 1 mR exposure were 0.36 and 0.21 for the ST-55BD and ST-VI phosphor plates, respectively. The differences between the spatial-frequency dependent DQE of the two plates can be attributed to the increased signal collection efficiency of the dual side read plates and differences in storage phosphor structure noise

220

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

S.R., Torelli; S.C., Rahal; R.S., Volpi; S., Yamashita; M.J., Mamprim; A.J., Crocci.

2004-04-01

 
 
 
 
221

Shielding Benchmark Computational Analysis  

International Nuclear Information System (INIS)

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)

222

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

Energy Technology Data Exchange (ETDEWEB)

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.

Bohndorf, K.; Sepehr, H.; Calavreszos, A.; Koschel, G.; Hain, E.

1985-03-01

223

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

International Nuclear Information System (INIS)

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.)

224

Cephalometric radiography and computed tomography in infants undergoing craniofacial surgery. A comparison  

Energy Technology Data Exchange (ETDEWEB)

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 regimen 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.

Lilja, J.; Friede, H.; Svendsen, P.; Aggeryd, J.; Lauritzen, C.; Moeller, M.; Andersson, H.; Johansson, B. (University of Goeteborg (Sweden))

1984-01-01

225

Cephalometric radiography and computed tomography in infants undergoing craniofacial surgery. A comparison  

Energy Technology Data Exchange (ETDEWEB)

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.

Lilja, J.; Friede, H.; Svendsen, P.; Aggeryd, J.; Lauritzen, C.; Moeller, M.; Andersson, H.; Johansson, B. (University of Goeteborg (Sweden))

1983-01-01

226

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

International Nuclear Information System (INIS)

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

227

Analysis of induced effects in matter during pulsed Nd:YAG laser welding by flash radiography  

Science.gov (United States)

Tantalum and TA6V (titanium alloy) are respectively used in corrosive chemical product containers and in aircraft and aerospace industries. The objective of this study was to analyze the dynamic behavior of the matter during deep laser spot welding of these materials. The obtained images should allow a better understanding of laser-matter interaction and should validate a model developed for porosities formation. Because of the afterglow of detectors, classical video x-ray systems are not suitable for the analysis of short dynamic effects during and after the laser pulse. An experimental device, based on a flash x-ray generator EUROPULSE 600 kV and a QUANTEL pulsed Nd:YAG laser, has been used. The flash x-ray generator is triggered, after a programmed delay, by the laser shot. The x-ray pulse duration is 30 ns. Welding parameters (pulse duration and energy) yield molten zones of 2 mm depth. Both materials, tantalum and TA6V, have been tested. Radiological films BIOMAX coupled with radioluminescent screens and direct exposure film (DEF) were respectively used for tantalum and TA6V samples. A fine collimation was studied to avoid the scattering effect in the material and in the radioluminescent screen. Radiological test samples, made of tantalum and TA6V, were performed to estimate the images qualities obtained by flash radiography. About 270 laser/x-rays shots were performed. The radiographic images have been digitalized and processed. The results show a deep and narrow capillary hole called "keyhole" which appears a few milliseconds after the beginning of the interaction. The "keyhole" hollows until the end of the laser pulse. After the end of the laser pulse, the molten bath collapses in less than 1 ms, trapping cavities.

Pascal, G.; Noré, D.; Girard, K.; Perret, O.; Naudy, P.

2000-05-01

228

Analysis of induced effects in matter during pulsed Nd:YAG laser welding by flash radiography  

International Nuclear Information System (INIS)

Tantalum and TA6V (titanium alloy) are respectively used in corrosive chemical product containers and in aircraft and aerospace industries. The objective of this study was to analyze the dynamic behavior of the matter during deep laser spot welding of these materials. The obtained images should allow a better understanding of laser-matter interaction and should validate a model developed for porosities formation. Because of the afterglow of detectors, classical video x-ray systems are not suitable for the analysis of short dynamic effects during and after the laser pulse. An experimental device, based on a flash x-ray generator EUROPULSE 600 kV and a QUANTEL pulsed Nd:YAG laser, has been used. The flash x-ray generator is triggered, after a programmed delay, by the laser shot. The x-ray pulse duration is 30 ns. Welding parameters (pulse duration and energy) yield molten zones of 2 mm depth. Both materials, tantalum and TA6V, have been tested. Radiological films BIOMAX coupled with radioluminescent screens and direct exposure film (DEF) were respectively used for tantalum and TA6V samples. A fine collimation was studied to avoid the scattering effect in the material and in the radioluminescent screen. Radiological test samples, made of tantalum and TA6V, were performed to estimate the images qualities obtained by flash radiography. About 270 laser/x-rays shots were performed. The radiographic images have been digitalized and processed. The results show a deep and narroocessed. The results show a deep and narrow capillary hole called 'keyhole' which appears a few milliseconds after the beginning of the interaction. The 'keyhole' hollows until the end of the laser pulse. After the end of the laser pulse, the molten bath collapses in less than 1 ms, trapping cavities

229

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

International Nuclear Information System (INIS)

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

230

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

231

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

International Nuclear Information System (INIS)

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

232

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

Energy Technology Data Exchange (ETDEWEB)

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.

Green, R E; Logan, C M; Martz, H E; Updike, E; Waters, A M

1999-05-01

233

Neutron radiography  

International Nuclear Information System (INIS)

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 (?s=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.

234

Ability of chest X-ray to detect faint shadows documented as ground-glass attenuation in images of computed tomography: A comparison between flat-panel detector radiography and film-screen radiography  

International Nuclear Information System (INIS)

Purpose: To compare flat-panel detector (FPD) radiography and film-screen (FS) radiography in detectability of faint shadows documented as ground-glass attenuation (GGA) areas in images of computed tomography (CT). Materials and methods: Study population was comprised of 50 patients who underwent FS and another 50 patients who underwent FPD. Standard of reference (SOR) was determined on the basis of area of GGA in all cross-sections of CT, in terms of GGA extent and presence or absence of GGA in each trisected lung fields (GGA distribution). Eight radiologists assessed the GGA extent with the 5-grade scale and the GGA distribution. Inter-observer variances of the GGA extents and distributions, degree of divergences and correspondence in the GGA extent and distributions with SOR, were compared between the FS and FPD by the jackknife method and Fisher's exact test. Results: Inter-observer variance in the GGA extent and distribution were slightly larger in the FS than in the FPD. The GGA extent scale corresponded with SOR in the FS statistically significantly better (p = 0.001), as the correct ratio was 0.428 in the FS and 0.310 in the FPD. Divergence in the GGA extent scale with SOR was smaller in the FS, as average kappa pseudo-value of Kendall's rank correlation coefficient was 0.474 in the FS and 0.433 in the FPD. Conclusion: These results indicate that some lesions of GGA documented in CT may not be reflected and are difficult to be detected in chest X-ray radiograplt to be detected in chest X-ray radiographs with the FPD.

235

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

International Nuclear Information System (INIS)

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

236

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

Science.gov (United States)

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.

Tang, Bin; Wu, Yang; Li, Hang; Sun, Yong; Huo, Heyong; Liu, Bin; Tang, Ke; Yin, Wei; Chao, Chao

2013-11-01

237

Neutron radiography  

International Nuclear Information System (INIS)

This paper discusses neutron radiography which produces images that look much like x-rays. But what they reveal is, in many ways, just the opposite of what x-rays reveal. Neutron radiography cannot show coins inside a purse or bones concealed by flesh. But it can show a plastic toy behind an inch of lead, oil flowing through a valve, or tiny roots growing through soil. The two types of radiography reveal different things because of a fundamental difference in the way x-rays and thermal neutrons interact with matter. X-rays interact with the electrons in the atoms of which a specimen is composed, and the higher the atomic number and the denser the specimen, the more the x-rays are attenuated. Thermal neutrons are unaffected by the specimen's electron content, since they have no charge. Instead, they interact with the specimen's atomic nuclei, and attenuation of the neutron flux depends on the way the nuclei deflect or absorb neutrons. This varies from one element to another, in ways that have nothing to do with atomic number

238

Neutron induced electron radiography  

International Nuclear Information System (INIS)

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 ?m in 24 ?m of aluminum at a resolution of 32 ?m. 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)

239

Indications for computed tomography (CT- diagnostics in proximal humeral fractures: a comparative study of plain radiography and computed tomography  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Precise indications for computed tomography (CT in proximal humeral fractures are not established. The purpose of this study was a comparison of conventional radiographic views with different CT reconstructions with 2 D and 3 D imaging to establish indications for additional CT diagnostics depending on the fractured parts. Methods In a prospective diagnostic study in two level 1 trauma centers, 44 patients with proximal humeral fractures were diagnosed with conventional X-rays (22 AP + axillary views, 22 AP + scapular Y-views and CT (multi-planar reconstruction (MPR and maximum intensity projection (MIP with 2 D and 3 D imaging. 3 observers assessed the technical image quality, the assessment of the relevant anatomical structures (2-sample-t-test and the percentage of the osseous overlap of the proximal humerus (Welch-test using a scoring system. The quality of the different diagnostic methods was assessed according to the number of fractured parts (Bonferroni-Holm adjustment. Results There was significantly more overlap of the fractured region on the scapular Y-views (mean 71.5%, range 45–90% than on axillary views (mean 56.2%, range 10.5–100%. CT-diagnostics allowed a significantly better assessment of the relevant structures than conventional diagnostics (p Conclusion Conventional X-rays with AP view and a high-quality axillary view are useful for primary diagnostics of the fracture and often but not always show a clear presentation of the relevant bony structures such as both tuberosities, the glenoid and humeral head. CT with thin slices technology and additional 3 D imaging provides always a clear presentation of the fractured region. Clinically, a CT should be performed – independently of the number of fractured parts – when the proximal humerus and the shoulder joint are not presented with sufficient X-ray-quality to establish a treatment plan.

Weise Kuno

2009-04-01

240

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  

International Nuclear Information System (INIS)

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,?) plane in 33.0 ms. Void fraction distribution for bubbly flow and slug flow is determined

 
 
 
 
241

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  

Energy Technology Data Exchange (ETDEWEB)

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.

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

242

Comparison of visual grading analysis and determination of detective quantum efficiency for evaluating system performance in digital chest radiography  

Energy Technology Data Exchange (ETDEWEB)

A study was conducted to compare physical and clinical system performance in digital chest radiography. Four digital X-ray modalities, two storage-phosphor based systems and two generations of a CCD-based system, were evaluated in terms of both their imaging properties (determination of presampling MTF and DQE) and clinical image quality (grading of the reproduction of anatomical details of 23 healthy volunteers using both absolute and relative visual grading analysis). One of the two storage-phosphor systems performed best in both evaluations and the first generation of the CCD-based system was rated worst; however, the other two systems were ranked differently with the two methods. The newest CCD-based system yielded a higher clinical image quality than the second storage-phosphor system, although the latter presented a DQE substantially higher than the former. The results show that clinical performance cannot be predicted from determinations of DQE alone, and that a system with lower DQE, under the quantum-saturated conditions in chest radiography, can outperform a system with higher DQE if the image processing used on the former is more effective in presenting the information in the image to the radiologist. (orig.)

Sund, Patrik; Baath, Magnus; Maansson, Lars Gunnar [Department of Radiation Physics, Goeteborg University, 41345 Goeteborg (Sweden); Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, 41345 Goeteborg (Sweden); Kheddache, Susanne [Department of Radiology, Goeteborg University, 41345 Goeteborg (Sweden); Department of Radiology, Sahlgrenska University Hospital, 41345 Goeteborg (Sweden)

2004-01-01

243

Radiography apparatus  

International Nuclear Information System (INIS)

The apparatus of the present invention provides radiography apparatus wherein the use of a flat, generally rectangular beam or a fan-shaped beam of radiation in combination with a collimator, scintillator and device for optically coupling a self-scanning array of photodiodes to the scintillator means will permit production of images or image data with high contrast sensitivity and detail. It is contemplated that the self-scanning array of photodiodes may contain from about 60 to 2048, and preferably about 256 to 2048, individual photodiode elements per inch of object width, thereby permitting maximum data collection to produce a complete image or complete collection of image data

244

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

International Nuclear Information System (INIS)

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 metastae 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)

245

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

International Nuclear Information System (INIS)

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.

246

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

Science.gov (United States)

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 with concrete imaging techniques and substantial diagnostic tools, which facilitate straightforward attainment and interpretation of field radiography images taken worldwide. PMID:24963807

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

247

Long-term evaluation of apical root resorption after orthodontic treatment using periapical radiography and cone beam computed tomography  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese OBJETIVO: avaliar a frequência de reabsorção radicular apical (RRA) após tratamento ortodôntico, em longo prazo, por meio de imagens de radiografia periapical (RP) e tomografia computadorizada de feixe cônico (TCFC). MÉTODOS: as imagens radiográficas obtidas de dentes de 58 pacientes, antes (T1), ap [...] ós o tratamento ortodôntico (T2) e decorridos pelo menos 52 meses do tratamento (T3), foram analisadas por três examinadores, membros do Board Brasileiro de Ortodontia e Ortopedia Facial. As estruturas apicais foram avaliadas por meio de imagens de RP (T2 e T3), utilizando o sistema de escores de Levander e Malmgren modificado. A presença de RRA nas imagens tomográficas obtidas em T3 foi detectada por um especialista em radiologia com experiência em TCFC. Os dados foram estatisticamente analisados pelo teste de Kolmogorov-Smirnov, com nível de significância de 5%. O teste kappa determinou o nível de concordância entre os observadores. RESULTADOS: as RRAs mais frequentes foram as de escore 1 em T2 (51,6%) e em T3 (53,1%), quando avaliadas por RPs (p > 0,05). Quando comparadas as frequências de RRAs em T3, entre imagens de RP e de TCFC, a diferença foi estatisticamente significativa para o grupo de pré-molares da maxila e da mandíbula, e de molares mandibulares. Os dentes que apresentaram maior frequência de RRA quando analisados por meio de imagens de TCFC, foram os incisivos laterais superiores (94,5%) e os centrais inferiores (87,7%), enquanto os de menor frequência foram os pré-molares. As imagens de TCFC mostraram que os dentes envolvidos em tratamentos ortodônticos com extrações apresentaram maior frequência de RRA (p Abstract in english OBJECTIVE: To evaluate the frequency of Apical Root Resorption (ARR) after orthodontic treatment at 52-288 months using periapical radiography (PR) and cone beam computed tomography (CBCT). METHODS: Radiographic images obtained from 58 patients, before (T1) and after orthodontic treatment (T2), and [...] following 52-288 months of treatment were analyzed by three members of the Brazilian Board of Orthodontics. Apical structures were evaluated by PR images (T2 and T3), using Levander and Malmgren scores. The presence of ARR on CBCT images were detected only at T3. The Kolmogorov-Smirnov test was used for statistical analyses, and the level of significance was set at 5%. Kappa statistics determined interobserver agreement. RESULTS: The more frequent ARR were with scores 1 in T2 (51.6%) and T3 (53.1%), when evaluated by PR (p > 0.05). When compared the frequencies of ARR in T3 among PR and CBCT images, the differences were significant for maxillary and mandibular pre-molar groups, and for mandibular molar group (p > 0.05). The teeth with highest frequency of ARR presence using CBCT images were maxillary lateral incisors (94.5%) and mandibular central incisors (87.7%), while the premolars showed the lowest frequency. The CBCT images showed that the teeth involved in orthodontic treatment with extraction present higher ARR frequency (p

Jairo Curado de, Freitas; Olavo César Porto, Lyra; Ana Helena Gonçalves de, Alencar; Carlos, Estrela.

2013-08-01

248

Retrospective patient dose analysis of Ghana's first direct digital radiography system.  

Science.gov (United States)

The log file generated in the flat panel detector of a direct digital x-ray machine (General Electric, Haulun Medical Systems, Serial Number 8M0392) after x-ray exposure was used to acquire data regarding the entrance surface air kerma (ESAK) for some routine x-ray examinations. The data were collected for a minimum of 10 standard adult patients undergoing each examination considered. The mean ESAK were found to be 0.25, 0.33, 0.14, 7.33, 9.76, 7.38, and 6.86 mGy for skull AP and LAT, chest AP, lumbar spine AP and LAT, pelvis AP and abdomen AP series, respectively. The mean ESAK values recorded from this study show wide variations but were below diagnostic reference levels (DRLs) of the Commission of European Communities and also compare with other recommendations. The comparisons of this study's dose levels with DRLs were undertaken as an approach to dose optimization. The study revealed that a dose audit of digital radiography systems is necessary because of the potential high doses one is likely to receive. Continuous dose evaluation in digital radiography is therefore encouraged in order to optimize doses to patients. PMID:22739831

Inkoom, Stephen; Togobo, James; Emi-Reynolds, Geoffrey; Oddoye, Adrian; Ntiri, Theophilus Ofosu; Gyekye, Prince Kwabena

2012-08-01

249

Normal development of the hip: a geometrical analysis based on planimetric radiography.  

Science.gov (United States)

The existing studies on the development of the hip joint predominantly focus on either the acetabulum or the proximal femur. This paper investigates the parallel geometrical development of both, the proximal femur and the acetabulum during growth. Six hundred and seventy-five hips with an age from 9 months to 16 years were studied by means of planimetric radiography; angles and lever arms were determined. Although the apophyseal angles remain virtually unchanged throughout growth, the epiphyseal angles and the neck-shaft angle undergo typical changes until the age of 10 years. Subsequently, there are no major changes in the angular conformation of the proximal femur, whereas acetabular coverage and its centric alignment continue to develop further until the end of skeletal growth. The load and muscle lever arms increase until the end of growth with their ratio remaining constant after the age of 10 years. We present correlated data on the geometrical development of the acetabulum and the proximal femur. The interpretation of our findings is to some extent limited by the two-dimensionality of planimetric radiography. Our results do, however, support the timing of corrective osteotomies of the proximal femur relatively soon after the age of 10 years. PMID:19829156

Birkenmaier, Christof; Jorysz, Gabriele; Jansson, Volkmar; Heimkes, Bernhard

2010-01-01

250

enhancement of neutron radiography  

International Nuclear Information System (INIS)

neutron radiography (NR) is a powerful non destructive testing (NDT) technique in viewing the internal details of objects and components. the advantage of nr over other NDT techniques is that nr can provide in come cases full detailed information that cannot be obtained by any other traditional techniques such as x-ray or gamma ray radiography. the image formation by nr can be degraded by many factors, the most important of which is scattering blur from the sample itself. previous attempts were made to correct scattering effects on neutron radiography, using computer software. in this thesis experimental work was carried out to enhance the image quality and increase the ETRR-2 nr facility sensitivity by scattered thermal neutrons deblurring, using two different techniques. the first technique is image enhancement using multilayer converter screens. the first technique is image enhancement using multilayer converter screens. the second technique is image deblurring using an anti scatter grid. the Monte Carlo N-particle (MCNP) code calculations were used to determine the best image formation from the multilayer converter screens technique . the code was also used in the design of the anti scatter grid dimensions and to find the fraction of thermal scattered neutrons removed by the grid

251

a-Si:H/CsI(Tl) flat-panel versus computed radiography for chest imaging applications: image quality metrics measurement  

International Nuclear Information System (INIS)

Amorphous silicon (a-Si:H) flat-panel (FP) imaging systems have recently become commercially available for both chest and mammographic imaging applications. It has been shown that this new detector technology offers better image quality and various operational advantages over the computed radiography (CR) which to date has been the most widely implemented and used digital radiography technique. However, most image quality measurements reported on flat-panel systems have been performed on prototype systems in laboratories while those for CR systems were typically independently performed and reported on in separate studies. To directly compare the two technologies, we have measured the image properties for a commercial amorphous silicon/cesium iodide [a-Si:H/CsI(Tl)] flat-panel based digital chest system and a commercial CR system under clinical imaging conditions. In this paper, measurements of image quality metrics, including the modulation transfer functions (MTFs), noise power spectra (NPSs), and detective quantum efficiencies (DQEs), for the FP and CR systems are presented and compared. Methods and issues related to these measurements are discussed. The results show that the flat-panel system has slightly lower MTF but significantly higher DQEs than the CR system. The DQEs of the flat-panel system were found to increase with the exposure while those of the CR system decrease slightly with the exposure

252

Development of advanced neutron radiography for inspection on irradiated fuels and materials. 3. Examination of neutron imaging plate and computed tomography methods on unirradiated fuel rod  

Energy Technology Data Exchange (ETDEWEB)

Advanced neutron radiography techniques such as neutron imaging plate (NIP) and Computed Tomography (CT) methods have been investigated in the practicability for Post Irradiation Examination (PIE). There are however few reports in terms of those techniques applied to the nuclear fuels. In this work, an unirradiated fuel rod was examined by NIP and CT methods in order to collect the fundamental data for applying these techniques to PIE. The used fuel rod is composed of seven-enriched UO{sub 2} pellet and two-natural UO{sub 2} pellet that are loaded into a Zircaloy tube. There are somewhat difference in the size and shape among those UO{sub 2} pellets. The neutron radiography tests were performed at TNRF-2 in JRR-3M. A transmitted and cross-sectional images were obtained by NIP and CT methods, respectively. In the NIP image of the fuel rod, the difference in the size, shape, and enrichment among the UO{sub 2} pellets is obviously recognized. In the case of CT method, the images clearly show the detailed shape of the cross section in both enriched and natural pellets, in addition, the difference in the enrichment between the natural and enriched pellets is recognized. (author)

Yasuda, Ryou; Matsubayashi, Masahito; Nakata, Masahito; Harada, Katsuya; Amano, Hidetoshi; Sasajima, Fumio; Nishi, Masahiro; Horiguchi, Youji [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Andou, Hitoshi [Radiation Application Development Association, Tokai, Ibaraki (Japan)

2002-02-01

253

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

International Nuclear Information System (INIS)

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)

254

Computational DNA Sequence Analysis  

Directory of Open Access Journals (Sweden)

Full Text Available DNA sequence is process of determining precise order of nucleotides within a DNA molecule. It is at the centre of human Genome project, which premises to revolutionaries the Bio-medical Sciences and the treatment of Human diseases. Extensive research and development has taken place over last few years in the areas of DNA Sequence Analysis. In this paper we have discussed aboutsome of the methods of DNA sequencing analysis, and the algorithm for DNA sequencing.

Archana Yashodhar*1 , Manjula*2, Praveen N *3, Pavithra K

2013-05-01

255

Evaluation of traumatic lateral cervical spine computed radiography images: quality control acceptability of images for clinical diagnosis, hardcopy versus high-resolution monitors  

Science.gov (United States)

The computed radiography images of 100 randomly selected traumatic cervical spine series were evaluated. The studies were reviewed on the laser printed hardcopy and 2K monitor soft copy images. In addition to the cervical vertebrae, the cervico-thoracic vertebral body interface must be recognized for a lateral c-spine image to be acceptable. The level of visualization of the spine was on average, 1/2 vertebral body better on the monitor than the hardcopy image. In 8% of cases, this improve visualization allowed clearance of the lateral cervical spine thereby expediting patient care in this critical area. This presentation will cover the quality of images and techniques to improve the success rate for clearing the cervical spine.

Leckie, Robert G.; Sheehy, Monet R.; Cade, Lawrence; Goeringer, Fred; Meyers, Chris A.; Parker, James E.; Smith, Donald V.; Freedman, Matthew T.

1993-06-01

256

Proton radiography in plasma  

International Nuclear Information System (INIS)

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.

257

Particle Beam Radiography  

Science.gov (United States)

Particle beam radiography, which uses a variety of particle probes (neutrons, protons, electrons, gammas and potentially other particles) to study the structure of materials and objects noninvasively, is reviewed, largely from an accelerator perspective, although the use of cosmic rays (mainly muons but potentially also high-energy neutrinos) is briefly reviewed. Tomography is a form of radiography which uses multiple views to reconstruct a three-dimensional density map of an object. There is a very wide range of applications of radiography and tomography, from medicine to engineering and security, and advances in instrumentation, specifically the development of electronic detectors, allow rapid analysis of the resultant radiographs. Flash radiography is a diagnostic technique for large high-explosive-driven hydrodynamic experiments that is used at many laboratories. The bremsstrahlung radiation pulse from an intense relativistic electron beam incident onto a high-Z target is the source of these radiographs. The challenge is to provide radiation sources intense enough to penetrate hundreds of g/cm2 of material, in pulses short enough to stop the motion of high-speed hydrodynamic shocks, and with source spots small enough to resolve fine details. The challenge has been met with a wide variety of accelerator technologies, including pulsed-power-driven diodes, air-core pulsed betatrons and high-current linear induction accelerators. Accelerator technology has also evolved to accommodate the experimenters' continuing quest for multiple images in time and space. Linear induction accelerators have had a major role in these advances, especially in providing multiple-time radiographs of the largest hydrodynamic experiments.

Peach, Ken; Ekdahl, Carl

2014-02-01

258

Digital chest radiography  

International Nuclear Information System (INIS)

The observer performance for video monitor images presented in positive mode ('bones black') was compared to that of images presented in negative mode ('bones white') in a digital system for chest radio-graphy based on large image intensifier. In the 1st part of the study, the original, non-linear grey-scale reversal performed in the computer of the digital image intensifier system (DS 1000) was studied together with fixed and variable settings of light and contrast. In the 2nd part true grey-scale reversal performed in a minicomputer (Micro-VAX II) where the images were also processed with edge and contrast enhancement, was studied. The time spent viewing the images was also recorded. Before the 2nd part of the study, the image intensifier system was optimized with regard to spatial and contrast resolution and dose settings. Simulated pathology was random positioned over the lungs and the mediastinum of an anthropomorphic phantom. Observer performance was evaluated with Receiver Operating Characteristic (ROC) analysis on the digital images. In the 1st part of the study, a significant advantage for the positive images was seen, but no significant difference between fixed and variable settings of light and contrast. In the 2nd part, no significant difference in the detectability of the test structures was seen between positive and negative images. A significant improvement in the detectability was seen between the 1st and the 2nd part of the study for the nodules over nd part of the study for the nodules over the mediastinum in both negative and positive images. No significant difference in the time spent observing positive and negative images, was seen. If negative mode is chosen for image presentation, true grey-scale reversal is necessary for adequate contrast resolution. (author). 11 refs.; 2 figs.; 1 tab

259

Fracture healing: direct magnification versus conventional radiography  

International Nuclear Information System (INIS)

The aim of the study was to evaluate the potential of magnification radiography in diagnosing fracture healing and assessing its complications. Seventy-three patients with fractures or who had undergone osteotomy were radiographed with both conventional (non-magnified) and magnification (5-fold) techniques. Since 10 patients were radiographed twice and 1 three times, 83 radiographs using each technique were obtained. All radiographs were analysed and the findings correlated with the patients' follow-up studies. The microfocal X-ray unit used for magnification radiography had a focal spot size of 20-130 ?m. As an imaging system, digital luminescence radiography was employed with magnification, while normal film-screen systems were used with conventional radiography. Magnification radiography proved superior to conventional radiography in 47% of cases: endosteal and periosteal callus formations were seen earlier and better in 26 cases, and osseous union could be evaluated with greater certainty in 33 cases. In 49% of cases magnification radiography was equal and in 4% inferior to conventional radiography. Additionally an ''inter-observer analysis'' was carried out. Anatomical and pathological structures were classified into one of four grades. Results were significantly (P < 0.01) better using magnification radiography. We conclude that the magnification technique is a good method for monitoring fracture healing in its early stages. (orig.)ges. (orig.)

260

Neutron radiography at the HFR Petten  

International Nuclear Information System (INIS)

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

 
 
 
 
261

PROTON RADIOGRAPHY FOR AN ADVANCED HYDROTEST FACILITY  

International Nuclear Information System (INIS)

Analysis of data from BNL experiment 933 is presented. Results demonstrate that proton radiography can meet many of the requirements for an Advanced Hydrotest Facility (AHF). Results for background, position resolution, metrology, quantitative radiography, material identification, and edge resolution are presented

262

Neutron radiography imaging of hydrogen containing materials  

International Nuclear Information System (INIS)

This work was performed at the dynamic neutron radiography station at the 10MW Budapest research reactor within the framework of the IAEA Co-ordinated Research Programme on ''Bulk Hydrogen Analysis, using Neutrons''. Neutron radiography has been successfully applied in various fields of hydrogen containing materials

263

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

International Nuclear Information System (INIS)

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.)

264

Industrial radiographies  

CERN Multimedia

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

2005-01-01

265

Computer techniques in EDXRF analysis  

International Nuclear Information System (INIS)

Different computer techniques presently used in EDXRF analysis are discussed. A comparison of the formerly used hardware structure with a modern multibus system with distributed functions, firmware capabilities and a floppy disk system is given. Software methods described include the language, the qualitative analysis, different background subtraction and peak deconvolution techniques and quantitative analysis approaches. Finally the typical software requirements for the industrial laboratory and the solutions available are summarized. (author)

266

“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  

Energy Technology Data Exchange (ETDEWEB)

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.

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

267

“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  

International Nuclear Information System (INIS)

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

268

Study of X-ray filter and peak kilovoltage in Fuji computed radiography in regard to the detection of simulated pulmonary nodules  

International Nuclear Information System (INIS)

To determine a suitable combination of X-ray filter and tube kilovoltage for Fuji Computed Radiography (FCR), provide better detection of pulmonary nodules, and reduce patient exposure, we compared observer performance with different X-ray filters and tube voltages. Radiographs were obtained with a copper filter backed by aluminium, with a tungsten filter backed by yttrium and aluminium, and with a lead filter backed by yttrium and aluminium, at both 100 kVp and 135 kVp. Observer performance in detecting simulated lung nodules, which were placed on the posterior aspect of a chest phantom, was compared using receiver operating characteristic (ROC) techniques for each combination of the X-ray filter and tube voltage. The results of the study indicated that 1) nodule detection was superior for the images obtained with 135 kVq as compared with 100 kVp; 2) approximately equal detection rates were obtained for the three X-ray filter sets, although results with the tungsten filter were slightly inferior to the other two filters; and 3) the absorbed dose may be reduced by 30% with the use of a lead filter backed by yttrium and aluminium compared with a copper filter backed by aluminium. We conclude that chest radiography with FCR should preferably be conducted with a higher kilovoltage, e.g., 135 kVp rather than 100 kVp, to ensure a higher detection rate of pulmonary nodules and in conjunction with a lead filter backed by yttrium and aluminium to reduce X-ray exposure to the patient. (author)

269

Statistical error analysis in computers, computer codes, and computed results  

International Nuclear Information System (INIS)

In constructing computers, setting up computer codes, and analyzing calculation results, errors must be taken into account which can best be assessed using statistical methods. The fundamental approach and mathematics, which are the same for all problems are briefly outlined. The application of statistical methods to the analysis of theoretical results is reported in some more detail. With the aid of a few examples, it is shown that these methods are widely applicable, that the results obtained are compatible with experience, and that statements are possible which cannot be obtained, or only with difficulties, by non-statistical methods. Some extensions of the present methods are proposed. The integration of this method in RSYST is described. This integration makes the methods available for general application to any code desired. (orig.)

270

Neutron radiography installations in the European Community  

International Nuclear Information System (INIS)

Tables are presented giving technical data and main utilization, exposure techniques, qualitative analysis and quantitative analysis, and future needs and requirements at neutron radiography installations in the European Community. Sketches of the various installations are also given. (Auth.)

271

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

International Nuclear Information System (INIS)

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)

272

Application of digital radiography to diagnosis of laryngeal diseases  

International Nuclear Information System (INIS)

Fuji Computed Radiography (FCR) is a new system of digital radiography that is based on the latest computer technologies. We applied this FCR system to the X-ray diagnosis of the laryngeal disease. Twenty patients with various laryngeal diseases were evaluated by both FCR frontal tomography and conventional screen-film frontal tomography under the same exposure condition. Both tomograms were then compared on the subject of the clarity of delineation of laryngeal structures. As the result, FCR tomograms revealed the feature of the laryngeal lumen and cartilages more clearly than conventional tomograms. In addition, energy subtraction method, which is one of FCR image processing systems, was presented as a new technical procedure to extinguish cervical spine shadows in plain anteroposterior laryngeal X-photograph. We stress that FCR system is the suitable procedure for X-ray analysis of laryngeal diseases, especially in the region related with the phono-surgery. (author)

273

Neutron-induced alpha radiography  

International Nuclear Information System (INIS)

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 ? - 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 ?m in thickness can be inspected with a spatial resolution of 32 ?m. 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 ?, ?, X-ray and visible light. (author)

274

Computational Aeroacoustic Analysis System Development  

Science.gov (United States)

Many industrial and commercial products operate in a dynamic flow environment and the aerodynamically generated noise has become a very important factor in the design of these products. In light of the importance in characterizing this dynamic environment, Rocketdyne has initiated a multiyear effort to develop an advanced general-purpose Computational Aeroacoustic Analysis System (CAAS) to address these issues. This system will provide a high fidelity predictive capability for aeroacoustic design and analysis. The numerical platform is able to provide high temporal and spatial accuracy that is required for aeroacoustic calculations through the development of a high order spectral element numerical algorithm. The analysis system is integrated with well-established CAE tools, such as a graphical user interface (GUI) through PATRAN, to provide cost-effective access to all of the necessary tools. These include preprocessing (geometry import, grid generation and boundary condition specification), code set up (problem specification, user parameter definition, etc.), and postprocessing. The purpose of the present paper is to assess the feasibility of such a system and to demonstrate the efficiency and accuracy of the numerical algorithm through numerical examples. Computations of vortex shedding noise were carried out in the context of a two-dimensional low Mach number turbulent flow past a square cylinder. The computational aeroacoustic approach that is used in CAAS relies on coupling a base flow solver to the acoustic solver throughout a computational cycle. The unsteady fluid motion, which is responsible for both the generation and propagation of acoustic waves, is calculated using a high order flow solver. The results of the flow field are then passed to the acoustic solver through an interpolator to map the field values into the acoustic grid. The acoustic field, which is governed by the linearized Euler equations, is then calculated using the flow results computed from the flow solver.

Hadid, A.; Lin, W.; Ascoli, E.; Barson, S.; Sindir, M.

2001-01-01

275

Radiography with polarised neutrons  

International Nuclear Information System (INIS)

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 tested on one Pd1-xNix sample and the results were compared with simulations of the temperature dependence of the neutron beam depolarisation by an inhomogeneous sample. As a result from these simulations a criterion was developed to assess the amount of heterogeneity in a sample from the shape of the temperature dependence of the beam polarisation after transmission of the sample. It is found from simulations that increasing the heterogeneity in the sample leads to a rounding of the signature of the phase transition in the depolarisation data. (orig.)

276

Radiography with polarised neutrons  

Energy Technology Data Exchange (ETDEWEB)

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 different ordering temperatures. This procedure was tested on one Pd{sub 1-x}Ni{sub x} sample and the results were compared with simulations of the temperature dependence of the neutron beam depolarisation by an inhomogeneous sample. As a result from these simulations a criterion was developed to assess the amount of heterogeneity in a sample from the shape of the temperature dependence of the beam polarisation after transmission of the sample. It is found from simulations that increasing the heterogeneity in the sample leads to a rounding of the signature of the phase transition in the depolarisation data. (orig.)

Schulz, Michael L.

2010-08-20

277

Computer aided safety analysis 1989  

International Nuclear Information System (INIS)

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

278

CGAT: computational genomics analysis toolkit.  

Science.gov (United States)

Computational genomics seeks to draw biological inferences from genomic datasets, often by integrating and contextualizing next-generation sequencing data. CGAT provides an extensive suite of tools designed to assist in the analysis of genome scale data from a range of standard file formats. The toolkit enables filtering, comparison, conversion, summarization and annotation of genomic intervals, gene sets and sequences. The tools can both be run from the Unix command line and installed into visual workflow builders, such as Galaxy. PMID:24395753

Sims, David; Ilott, Nicholas E; Sansom, Stephen N; Sudbery, Ian M; Johnson, Jethro S; Fawcett, Katherine A; Berlanga-Taylor, Antonio J; Luna-Valero, Sebastian; Ponting, Chris P; Heger, Andreas

2014-05-01

279

Blow-out fractures of the orbit: a comparison of computed tomography and conventional radiography with anatomic correlation  

International Nuclear Information System (INIS)

Orbital blow-out fractures were experimentally created in eight human cadavers. Each orbit underwent conventional radiographic studies, complex motion tomography, and computed tomographic examinations. A comparison of the three modalities was made. Anatomical correlation was obtained by dissecting the orbits. The significance of medial-wall fractures and enophthalmos is discussed. Limitation of inferior rectus muscle mobility is thought to be a result of muscle kinking associated with orbital fat-pad prolapse at the fracture site, rather than muscle incarceration. Blow-out fractures should be evaluated by computed tomographic computer reformations in the oblique sagittal plane

280

Blow-out fractures of the orbit: a comparison of computed tomography and conventional radiography with anatomic correlation  

Energy Technology Data Exchange (ETDEWEB)

Orbital blow-out fractures were experimentally created in eight human cadavers. Each orbit underwent conventional radiographic studies, complex motion tomography, and computed tomographic examinations. A comparison of the three modalities was made. Anatomical correlation was obtained by dissecting the orbits. The significance of medial-wall fractures and enophthalmos is discussed. Limitation of inferior rectus muscle mobility is thought to be a result of muscle kinking associated with orbital fat-pad prolapse at the fracture site, rather than muscle incarceration. Blow-out fractures should be evaluated by computed tomographic computer reformations in the oblique sagittal plane.

Hammeschlag, S.B. (Harvard Medical School, Boston, MA); Hughes, S.; O' Reilly, G.V.; Naheedy, M.H.; Rumbaugh, C.L.

1982-05-01

 
 
 
 
281

Digital radiography versus conventional radiography during excretory urography: our experience  

International Nuclear Information System (INIS)

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

282

Computational analysis of cerebral cortex  

Energy Technology Data Exchange (ETDEWEB)

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.)

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

2010-08-15

283

Computational analysis of cerebral cortex  

International Nuclear Information System (INIS)

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.)

284

Evidence-based radiography  

Energy Technology Data Exchange (ETDEWEB)

Evidence-based practice (EBP) offers the integration of the best research evidence with clinical knowledge and expertise and patient values. EBP is a well known term in health care. This paper discusses the implementation of EBP into radiography and introduces the term evidence-based radiography. Evidence-based radiography is radiography informed and based on the combination of clinical expertise and the best available research-based evidence, patient preferences and resources available. In Norway, EBP in radiography is being debated and radiographers are discussing the challenges of implementing EBP in both academic and clinical practice. This discussion paper explains why EBP needs to be a basis for a radiography curriculum and a part of radiographers' practice. We argue that Norwegian radiographers must increase participation in research and developing practice within their specific radiographic domain.

Hafslund, Bjorg [Institute of Radiography, Faculty of Health and Social Sciences, Bergen University College, P.O. Box 7030, N-5020 Bergen (Norway)], E-mail: bhaf@hib.no; Clare, Judith; Graverholt, Birgitte; Wammen Nortvedt, Monica [Centre for Evidence Based Practice, Faculty of Health and Social Sciences, Bergen University College, Bergen (Norway)

2008-11-15

285

Computational system for geostatistical analysis  

Directory of Open Access Journals (Sweden)

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.

Vendrusculo Laurimar Gonçalves

2004-01-01

286

Development of an automated method for analysis of Winston-Lutz test results using digital radiography and photostimulable storage phosphor  

International Nuclear Information System (INIS)

Stereotactic radiosurgery (SRS) and radiotherapy (SRT) are intricate techniques that deliver a highly precise radiation dose to a localized target, usually a tumor. At our hospital, we perform SRS and SRT on brain tumors using a linear accelerator (linac) mounted with an external micro multi-leaf system. The Task Group TG-142 Report by the American Association of Physicists in Medicine recommends the coincidence of the radiation and mechanical isocenter to be within ±1 mm. The Winston-Lutz test is commonly used to verify the linac isocenter position: it has the advantages of being a simple method that uses a film or electronic portal imaging device (EPID). However, the film method requires a higher radiation dose, which makes it more time-consuming than the EPID method, and the results are highly dependent on the skills of the observer. The EPID method has certain advantages over the film method, but it has low resolution and can only be used for a few combinations of gantry and couch angles. This prompted us to develop an in-house-designed radiation receptor system based on digital radiography, using a photostimulable storage phosphor and automated analysis algorithm for Winston-Lutz test images using a template-matching technique based on cross-correlation coefficients. Our proposed method shows a maximum average absolute error of 0.222 mm (less than 2 pixels) for 0.5 mm and 1.0 mm displacement from the isocenter toward the inline and crossline directions. Our proposed method is thus potentially useful for verifying the Linac isocenter position with a small error and good reproducibility, as demonstrated by improved accuracy of evaluation. (author)

287

Magnification radiography in osteomyelitis  

International Nuclear Information System (INIS)

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.)

288

Forensic Analysis of Compromised Computers  

Science.gov (United States)

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.

Wolfe, Thomas

2004-01-01

289

Proton nuclear scattering radiography  

International Nuclear Information System (INIS)

Nuclear scattering of protons allows to radiograph objects with specific properties: direct 3- dimensional radiography, different information as compared to X-ray technique, hydrogen radiography. Furthermore, it is a well adapted method to gating techniques allowing the radiography of fast periodic moving systems. Results obtained on different objects (light and heavy materials) are shown and discussed. The dose delivery is compatible with clinical use, but at the moment, the irradiation time is too long between 1 and 4 hours. Perspectives to make the radiography faster and to get a practical method are discussed

290

Proton nuclear scattering radiography  

International Nuclear Information System (INIS)

Nuclear scattering of protons allows to radiograph objects with specific properties: 3-dimensional radiography, different information as compared to X-ray technique, hydrogen radiography. Furthermore the nuclear scattering radiography (NSR) is a well adapted method to gating techniques allowing the radiography of fast periodic moving objects. Results obtained on phantoms, formalin fixed head and moving object are shown and discussed. The dose delivery is compatible with clinical use, but at the moment, the irradiation time is too long between 1 and 4 hours. Perspectives to make the radiograph faster and to get a practical method are discussed

291

Digital radiography  

International Nuclear Information System (INIS)

In this review, we present the current results of our schemes for computerized automated analysis that are being developed at the University of Chicago for 1) the identification of lung nodules, the assessment of interstitial disease and cardiomegaly in chest radiographs; 2) the identification of clustered microcalcifications and masses in mammography; and 3) the assessment of stenotic lesions in angiograms. (orig./MG)

292

Filmless radiology - digital radiography systems  

International Nuclear Information System (INIS)

The article presents new digital radiography systems. The principles of digital radiography and differences between traditional and digital radiography units are discussed. Two types of digital radiography systems are compared. The principles of the Picture Archiving and Communication System (PACS), Radiological Information System (RIS), and Hospital Information System (HIS) connected with digital radiography are presented. The benefits of digital radiography for hospitals, radiologists, physicians, and patients are discussed. (authors)

293

Computer aided analysis of disturbances  

International Nuclear Information System (INIS)

Computer aided analysis of disturbances and the prevention of failures (diagnosis and therapy control) in technological plants belong to the most important tasks of process control. Research in this field is very intensive due to increasing requirements to security and economy of process control and due to a remarkable increase of the efficiency of digital electronics. This publication concerns with analysis of disturbances in complex technological plants, especially in so called high risk processes. The presentation emphasizes theoretical concept of diagnosis and therapy control, modelling of the disturbance behaviour of the technological process and the man-machine-communication integrating artificial intelligence methods, e.g., expert system approach. Application is given for nuclear power plants. (author)

294

Analysis of muon radiography of the Toshiba nuclear critical assembly reactor  

International Nuclear Information System (INIS)

A 1.2?×?1.2 m2 muon tracker was moved from Los Alamos to the Toshiba facility at Kawasaki, Japan, where it was used to take ?4 weeks of data radiographing the Toshiba Critical Assembly Reactor with cosmic ray muons. In this paper, we describe the analysis procedure, show results of this experiment, and compare the results to Monte Carlo predictions. The results validate the concept of using cosmic rays to image the damaged cores of the Fukushima Daiichi reactors

295

Quantitative neutron radiography using neutron absorbing honeycomb  

International Nuclear Information System (INIS)

This investigation concerns quantitative neutron radiography and computed tomography by using a neutron absorbing honeycomb collimator. By setting the neutron absorbing honeycomb collimator between object and imaging system, neutrons scattered in the object were absorbed by the honeycomb material and eliminated before coming to the imaging system, but the neutrons which were transmitted the object without interaction could reach the imaging system. The image by purely transmitted neutrons gives the quantitative information. Two honeycombs were prepared with coating of boron nitride and gadolinium oxide and evaluated for the quantitative application. The relation between the neutron total cross section and the attenuation coefficient confirmed that they were in a fairly good agreement. Application to quantitative computed tomography was also successfully conducted. The new neutron radiography method using the neutron-absorbing honeycomb collimator for the elimination of the scattered neutrons improved remarkably the quantitativeness of the neutron radiography and computed tomography. (author)

296

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

International Nuclear Information System (INIS)

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

297

Research Analysis of Cloud Computing?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cloud Computing is the emerging buzzword in Information Technology. It is growing day by daydue to its rich features of services. It is a virtual pool of resources which are provided to the users throughInternet. Cloud computing is a new flavor of computing where our trend of using Internet changes. It is thefuture of Internet. It is also called as fifth generation of computing after Mainframe, Personal Computer,Client-Server Computing, and the Web. Nowadays, various Internet services are ava...

Vijay Baskar, G.; Sathees Kumar, N.; Karthick?, N.

2013-01-01

298

Crush extremity fractures associated with the 2008 Sichuan earthquake: anatomic sites, numbers and statuses evaluated with digital radiography and multidetector computed tomography  

International Nuclear Information System (INIS)

To investigate features of crush extremity fractures associated with massive earthquake on digital radiography (DR) and multidetector computed tomography (MDCT). Six hundred and twenty-three consecutive patients with clinically confirmed crush extremity fractures arising from the 2008 Sichuan earthquake were enrolled into our study. Six hundred and eleven patients with suggested extremity fractures underwent DR, and 12 patients with possible knee fractures underwent MDCT. Image data were retrospectively reviewed, with the focus on anatomic sites, numbers, and status of the fractures. Extremity fractures occurred in lower extremities in 428 patients, upper extremities in 151, and both lower and upper extremities in 44. Lower extremity fractures were more common than upper extremity fractures (P < 0.05), and the commonly involved bones were the tibia and fibula in 141 patients, femur in 102, tibia in 52, and fibula in 40. According to the numbers of bones involved, multiple bone fractures occurred in 336 patients and included lower extremity fractures in 231, upper extremity fractures in 61, and both lower and upper fractures in 44. Multiple fractures in lower extremities were seen more often than in upper extremities (P < 0.05). As for status of the extremity fractures, comminuted fractures occurred in 324 patients and included lower extremity fractures in 248, upper extremity fractures in 51, and both lower and upper extremity fractures in 25. Comminuted fractures were more common in lower extremities than in upper extremities (P < 0.05). Multiple and comminuted fractures, predominantly in the lower extremities, could be considered as features of crush extremity fractures associated with the massive Sichuan earthquake. (orig.)

299

Displaying radiologic images on personal computers: image processing and analysis.  

Science.gov (United States)

This is the fourth article of our series for radiologists and imaging scientists on displaying, manipulating, and analyzing radiologic images on personal computers. Classic image processing is divided into point, area, frame, and geometric processes. Point processes change image pixel values based on the value of the pixel of interest. Histogram equalization adjusts the pixel values in the image based on the distribution of pixel values. Area processes change the pixel of interest based on the values of the surrounding pixels, known as the neighborhood. Area processes using a convolution kernel are often used as image filters. Common convolution kernels include low-frequency, high-frequency, and edge-enhancement filters. Edge enhancement can be performed with convolution kernels such as shift and difference, gradient-directional and Laplacian filters, or with nonlinear methods such as Sobel's algorithm. Frame processes mathematically combine two or more images, often for noise reduction and background subtraction. Geometric processes alter the location of pixels within the image, but usually not the pixel values. Common radiologic applications of image processing include window width and window level adjustments (point process), adaptive histogram equalization (area process), unsharp masking (area process), computed radiography image processing (combined area and point processes), digital subtraction angiography (frame and geometric processes), region of interest analysis (area process), and image rotation (geometric process). As digital imaging becomes more widespread, radiologists need to understand the image processing that is fundamental to these modalities. PMID:8075184

Gillespy, T; Rowberg, A H

1994-05-01

300

Comparison of cone-beam computed tomography and periapical radiography in predicting treatment decision for periapical lesions: a clinical study.  

Science.gov (United States)

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 (?(2)(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. PMID:23056050

Balasundaram, Ashok; Shah, Punit; Hoen, Michael M; Wheater, Michelle A; Bringas, Josef S; Gartner, Arnold; Geist, James R

2012-01-01

 
 
 
 
301

Effect on image processing on diagnostic decisions in chest radiography  

Science.gov (United States)

The goal of this study was to determine what the influence of image processing functions was on decisions and decision changes made while reading chest radiographs displayed on a monitor. Six radiologists read 168 computed radiography chest images first without them with the use of six image processing functions. Diagnostic performance was measured using receiver operating characteristic analysis, and decision changes made without and with processing use were analyzed. Diagnostic performance did not differ statistically for readings without and with image processing. The decision change analysis showed that readers were just as likely to change decisions from true-positive to false-negative as they were from false-negative to true- positive. With image processing, there were significantly more changes from true-negative to false-positive than from false-positive to true-negative. 93 percent of all decisions did not change with the use of image processing. No significant correlations were found between the type of lesions present on the radiography and the type of image processing function sued. Positive decision changes made with the use of image processing are offset by equivalent numbers of negative decision changes. The use of image processing does not affect significantly diagnostic performance in chest radiography.

Krupinski, Elizabeth A.; Evanoff, Michael G.

1998-04-01

302

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

Energy Technology Data Exchange (ETDEWEB)

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 those with protected characteristics. A number of actions regarding the delivery and administration of the programmes have been identified from this study.

Hussain, Zainab, E-mail: zay@liv.ac.u [Directorate of Medical Imaging and Radiotherapy, School of Health Sciences, University of Liverpool, Liverpool L69 3GB (United Kingdom); Pickering, Vicki, E-mail: vmoscrip@liv.ac.u [Directorate of Medical Imaging and Radiotherapy, School of Health Sciences, University of Liverpool, Liverpool L69 3GB (United Kingdom); Percy, Dave, E-mail: D.F.Percy@salford.ac.u [Operational Research and Applied Statistics, Salford Business School, University of Salford, Greater Manchester, M5 4WT (United Kingdom); Crane, Julie, E-mail: abbotj@liv.ac.u [Directorate of Nursing, School of Health Sciences, University of Liverpool, Liverpool L69 3GB (United Kingdom); Bogg, Jan, E-mail: jbogg@liv.ac.u [Population, Community and Behavioural Sciences, University of Liverpool, Liverpool L69 3GB (United Kingdom)

2011-02-15

303

Computed radiography and MRI evaluation of a novel functional brace for conservative treatment of subcutaneous Achilles tendon rupture  

International Nuclear Information System (INIS)

A total of 267 patients were conservatively treated using novel functional braces. In 34 patients, we observed healing process of the Achilles tendon in a series of magnetic resonance (MR) and computed radiogram (CR) images. CR images were taken periodically, while MR images were obtained at onset of injury and 3 to 4 weeks, 9 to 10 weeks, and 4 to 5 months after injury. We assessed the morphology of the ruptured tendon section by observing intensity changes in the periodic MR examinations. During early conservative therapy (3 to 4 weeks), dumbbell-shaped tendons were most common. At 9 to 10 weeks (i.e., when the brace was removed), tendon continuity was observed at the rupture site; the average antero-posterior tendon diameter was 8.5 mm. Most areas were of low signal intensity, although some areas of moderate signal intensity remained. The tendons of 22 patients had an hourglass shape, while those of 12 patients were spindle shaped. Four to 5 months after injury (i.e., when patients resumed athletic activity), tendon continuity had further improved, and average antero-posterior tendon diameter had increased to 13.8 mm. The entire tendon displayed uniformly low signal intensity. A brace is a straightforward method of treating Achilles tendon ruptures. Because of difficulties in image interpretation, it seems unlikely that CR will become widely used in the diagnosis and monitoring of tendon rupture. The results indicate that the use of MR imaging on an as-needed basishe use of MR imaging on an as-needed basis provides a superior understanding of tendon rupture healing. We conclude that further clinical application of MR imaging is warranted. (author)

304

Component analysis of image noise on digital radiography on the basis of empirical formula. X-ray energy-dependence of noise components  

International Nuclear Information System (INIS)

The purpose of our study is to devise the empirical formula of image noise for digital radiography and to investigate the relationship between image noise components and radiation dose using the empirical formula. Two kinds of commercially available phantoms were prepared as target objects: ACR 156 phantom and CDRAD phantom. To devise the empirical formula of image noise, the ACR phantom images were obtained using a full-field digital mammography system. To investigate the relationship between radiation dose and image noise components, the CDRAD phantom images were acquired using computed radiography system. The empirical formula of image noise was devised using the mean values and the standard deviations (noise SD) for pixel values in rectangular areas (ROI) in un-processed ACR 156 phantom images. We have demonstrated that the noise variance (noise SD2) can be represented as a quadratic function of the mean value and the quadratic, linear, and constant terms in this formula associate with structural noise, quantum noise, and electronic noise, respectively. For low radiation dose, quantum noise had the largest contribution to image noise. In contrast, for high radiation dose, structural noise was the dominant source. Furthermore, quantum and structural noises increased with the effective energy of X-ray. (author)

305

Personal Computer Transport Analysis Program  

Science.gov (United States)

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.

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

2012-01-01

306

Bone X-Ray (Radiography)  

Medline Plus

Full Text Available X-ray (Radiography) - Bone Play Video Clip (00:04:40) Your Radiologist Explains Bone X-ray What is Bone X-ray (Radiography)? What ... limitations of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is ...

307

Bone X-Ray (Radiography)  

Science.gov (United States)

X-ray (Radiography) - Bone Play Video Clip (00:04:40) Your Radiologist Explains Bone X-ray What is Bone X-ray (Radiography)? What ... limitations of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is ...

308

Neutron radiography, techniques and applications  

International Nuclear Information System (INIS)

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)

309

Recent developments in radiography  

International Nuclear Information System (INIS)

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

310

Research Analysis of Cloud Computing?  

Directory of Open Access Journals (Sweden)

Full Text Available Cloud Computing is the emerging buzzword in Information Technology. It is growing day by daydue to its rich features of services. It is a virtual pool of resources which are provided to the users throughInternet. Cloud computing is a new flavor of computing where our trend of using Internet changes. It is thefuture of Internet. It is also called as fifth generation of computing after Mainframe, Personal Computer,Client-Server Computing, and the Web. Nowadays, various Internet services are available in distributedmanner. To use these services in a feasible manner is a big question because sometimes many resourcesbecome idle, they are costly and increase the budget of organization. This is the great matter of concern,especially when the world is facing financial crisis. Cloud Computing can be the answer of these questions.In this paper, we have analyzed and highlighted the various aspects of Cloud Computing to find the actualityof the fifth generation computing in the form of cloud computing.

G. Vijay Baskar

2013-05-01

311

Patient risk from interproximal radiography  

International Nuclear Information System (INIS)

Computer simulation methods for determining patient dose from dental radiography have demonstrated that patient risk from a two-film interproximal examination ranges from 1.1 X 10(-8) to 3.4 X 10(-7) using 90-kVp beams, depending on film speed, projection technique, and age and sex of the patient. Further, changing from a short-cone round-beam to a long-cone technique with rectangular collimation reduces risk by a factor of 2.9, independent of other factors

312

Ion medical radiography  

International Nuclear Information System (INIS)

Considered are physical principles of ion radiography, its methods (the method of residual range, the nuclear scattering method), the results of investigation of animals, tissues of the human organism, of the patient. The perspectiveness of ion radiography in diagnosis of not only neoplasms, but of other serious deseases is shown. The variants of accelerator projects for ion radiography are discussed. Some aspects of utilization of charged particle detectors and requirements to the beam parameters are elucidated. Shown are the advantages of ion application: lower irradiation doses, higher picture contrast than in case of roentgenography, possible differentiation of soft tissues and observation of small anomalies in them. The potentialities of ion radiography and prospects of its development are discussed

313

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

314

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

International Nuclear Information System (INIS)

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.)

315

Análisis del Patrón Óseo Trabecular de Mandíbulas Maceradas en Radiografías Panorámicas Digitales Analysis of the Trabecular Bone Pattern of Dry Human Mandibles in Digital Panoramic Radiographies  

Directory of Open Access Journals (Sweden)

Full Text Available Nuestro propósito fue estudiar la sensibilidad de la metodología de esqueletonizacion en las alteraciones del patrón óseo trabecular, en radiografías panorámicas digitales. Con el fin de poder utilizar esta metodología a futuro para el análisis y la observación de los cambios de densidad ósea en la estructura trabecular, en pacientes con osteoporosis y sanos. El material examinado consistió en cinco mandíbulas adultas, maceradas. Los 4 sitios de interés de cada mandíbula fueron escogidos en cuerpo mandibular, debajo de los alvéolos dentarios: Sitio 1. Oral y anterior al foramen mentoniano derecho. Sitio 2. Oral y posterior al foramen mentoniano derecho. Sitio 3. Oral y anterior al foramen mentoniano izquierdo. Sitio 4. Oral y posterior al foramen mentoniano izquierdo. Se realizó la toma de radiografías panorámicas digitales. Posterior a la primera toma radiográfica, se recortaron las áreas delimitadas removiendo las tablas vestibulares, Se fracturó intencionalmente el trabeculado óseo y luego se reubicaron las tablas vestibulares y se realizó una segunda toma radiográfica, con el uso de un soporte confeccionado para el posicionamiento de las mandíbulas, manteniendo las líneas guía fijas,para cada especimen: Plano mediano, Línea canina y Plano de Frankfurt. Los sitios de interés fueron trabajados en software, siguiendo el método empleado por Watanabe (2003, las imágenes resultantes, que muestran los esqueletos de las trabéculas óseas fueron analizadas utilizando las siguientes herramientas: Histograma, Análisis de partículas, Dimensión fractal, Cantidad de Uniones o encuentro triple de trabéculas y Porcentaje de trabéculas por área. En el análisis estadístico según los datos obtenidos de las diferentes regiones, antes y después de la remoción/inserción, no se encontró una diferencia estadísticamente significativa. Las trabéculas vistas en la radiografía panorámica son formadas principalmente por inserciones en las corticales. El método de retirar la tabla ósea proporcionó apenas una ruptura en el interior (segmento del cuerpo mandibularThe objective investigation is to study and analyze the sensibility of the esqueletonization methodology in the alterations of the trabecular bone pattern in digital panoramic radiographies. In order to use this analysis and look changes in the bone density in the trabecular structure in healthy patients and with osteoporosis.The elements analyzed consist in five dry human mandibles. The four studied zones of each mandible were selected in the mandible body under the alveolar bone, studied zones: 1 Bucal and anterior to the right mental foramen, 2 Bucal and posterior to the right mental foramen, 3 Bucal and anterior to the left mental foramen, 4 Bucal and posterior to the left mental foramen.We realized the digital panoramic radiographies. After the first radiography we cut the delimited areas removing the buccal cortical plates. we did intentional fractures in the trabecular bone. Then we replace the buccal cortical plates and realized the second radiography, using the support created for the mandibles replacement, maintaining the fixed guide lines for each specimen. mid Sagital plane, canine line and Frankfurt Plane.The studied zones were analyzed in the software using the Watanabe 2003 Method. The studied images that show the trabecular bone squeleton were analyzed using: Histogram, particulas analysis, Fractal dimension, unions quantity or trabecuialr third union and the trabecular percent.The statistical analysis of the different zones before and after of the renovation and insertion didn't show a statistical important difference. The trabecular that the panoramic radiography showed were formed for the insertions in the corticals. The method of take off the cortical bone plates just breaks part inside the mandible body

Plauto Christopher Aranha Watanabe

2006-09-01

316

Análisis del Patrón Óseo Trabecular de Mandíbulas Maceradas en Radiografías Panorámicas Digitales / Analysis of the Trabecular Bone Pattern of Dry Human Mandibles in Digital Panoramic Radiographies  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Nuestro propósito fue estudiar la sensibilidad de la metodología de esqueletonizacion en las alteraciones del patrón óseo trabecular, en radiografías panorámicas digitales. Con el fin de poder utilizar esta metodología a futuro para el análisis y la observación de los cambios de densidad ósea en la [...] estructura trabecular, en pacientes con osteoporosis y sanos. El material examinado consistió en cinco mandíbulas adultas, maceradas. Los 4 sitios de interés de cada mandíbula fueron escogidos en cuerpo mandibular, debajo de los alvéolos dentarios: Sitio 1. Oral y anterior al foramen mentoniano derecho. Sitio 2. Oral y posterior al foramen mentoniano derecho. Sitio 3. Oral y anterior al foramen mentoniano izquierdo. Sitio 4. Oral y posterior al foramen mentoniano izquierdo. Se realizó la toma de radiografías panorámicas digitales. Posterior a la primera toma radiográfica, se recortaron las áreas delimitadas removiendo las tablas vestibulares, Se fracturó intencionalmente el trabeculado óseo y luego se reubicaron las tablas vestibulares y se realizó una segunda toma radiográfica, con el uso de un soporte confeccionado para el posicionamiento de las mandíbulas, manteniendo las líneas guía fijas,para cada especimen: Plano mediano, Línea canina y Plano de Frankfurt. Los sitios de interés fueron trabajados en software, siguiendo el método empleado por Watanabe (2003), las imágenes resultantes, que muestran los esqueletos de las trabéculas óseas fueron analizadas utilizando las siguientes herramientas: Histograma, Análisis de partículas, Dimensión fractal, Cantidad de Uniones o encuentro triple de trabéculas y Porcentaje de trabéculas por área. En el análisis estadístico según los datos obtenidos de las diferentes regiones, antes y después de la remoción/inserción, no se encontró una diferencia estadísticamente significativa. Las trabéculas vistas en la radiografía panorámica son formadas principalmente por inserciones en las corticales. El método de retirar la tabla ósea proporcionó apenas una ruptura en el interior (segmento) del cuerpo mandibular Abstract in english The objective investigation is to study and analyze the sensibility of the esqueletonization methodology in the alterations of the trabecular bone pattern in digital panoramic radiographies. In order to use this analysis and look changes in the bone density in the trabecular structure in healthy pat [...] ients and with osteoporosis.The elements analyzed consist in five dry human mandibles. The four studied zones of each mandible were selected in the mandible body under the alveolar bone, studied zones: 1) Bucal and anterior to the right mental foramen, 2) Bucal and posterior to the right mental foramen, 3) Bucal and anterior to the left mental foramen, 4) Bucal and posterior to the left mental foramen.We realized the digital panoramic radiographies. After the first radiography we cut the delimited areas removing the buccal cortical plates. we did intentional fractures in the trabecular bone. Then we replace the buccal cortical plates and realized the second radiography, using the support created for the mandibles replacement, maintaining the fixed guide lines for each specimen. mid Sagital plane, canine line and Frankfurt Plane.The studied zones were analyzed in the software using the Watanabe 2003 Method. The studied images that show the trabecular bone squeleton were analyzed using: Histogram, particulas analysis, Fractal dimension, unions quantity or trabecuialr third union and the trabecular percent.The statistical analysis of the different zones before and after of the renovation and insertion didn't show a statistical important difference. The trabecular that the panoramic radiography showed were formed for the insertions in the corticals. The method of take off the cortical bone plates just breaks part inside the mandible body

Plauto Christopher Aranha, Watanabe; Solange Aparecida Caldeira, Monteiro; Joyce Carvalho Tenfuss, Campbell; David Alberto Aristizabal, Elejalde.

317

Analysis of micro computed tomography images; a look inside historic enamelled metal objects  

Science.gov (United States)

In this study the usefulness of micro-Computed Tomography (µ-CT) for the in-depth analysis of enamelled metal objects was tested. Usually investigations of enamelled metal artefacts are restricted to non-destructive surface analysis or analysis of cross sections after destructive sampling. Radiography, a commonly used technique in the field of cultural heritage studies, is limited to providing two-dimensional information about a three-dimensional object (Lang and Middleton, Radiography of Cultural Material, pp. 60-61, Elsevier-Butterworth-Heinemann, Amsterdam-Stoneham-London, 2005). Obtaining virtual slices and information about the internal structure of these objects was made possible by CT analysis. With this technique the underlying metal work was studied without removing the decorative enamel layer. Moreover visible defects such as cracks were measured in both width and depth and as of yet invisible defects and weaker areas are visualised. All these features are of great interest to restorers and conservators as they allow a view inside these objects without so much as touching them.

van der Linden, Veerle; van de Casteele, Elke; Thomas, Mienke Simon; de Vos, Annemie; Janssen, Elsje; Janssens, Koen

2010-02-01

318

High quality neutron radiography  

International Nuclear Information System (INIS)

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.)

319

Computer-Based Linguistic Analysis.  

Science.gov (United States)

Noam Chomsky's transformational-generative grammar model may effectively be translated into an equivalent computer model. Phrase-structure rules and transformations are tested as to their validity and ordering by the computer via the process of random lexical substitution. Errors appearing in the grammar are detected and rectified, and formal…

Wright, James R.

320

New neutron radiography facility at INR Pitesti with extended applications  

International Nuclear Information System (INIS)

To enlarge the applications of neutron radiography and to make it easier as compared with underwater facility, a new dry neutron radiography facility at tangential beam tube of the TRIGA-ACPR is in construction. Former investigations for the placement of the facility, neutron radiography tests performed through transfer method involving indium and dysprosium foils and radiographic films and the thermal neutron flux determinations by neutron activation analysis of indium and gold foils established that there are opportunities for the construction of a performance neutron radiography facility. The measured thermal neutron flux values were: 1.1 x 1012 n/cm2s near core and 1.12 x 106 n/cm2s at the exit of tangential beam tube, at 100 kW operating power of ACPR. The following components of the facility were designed: collimator for neutrons, shield for protection, holder for investigated samples, detection system, biological protection and surveillance system. The collimator for neutrons is of divergent type and consists in two components placed inside the tangential beam tube. The first component ensures a thermal neutron current toward the exit of the beam tube (with a low level of ? radiation, epithermal and fast neutron content). The second component ensures a low level of scattered neutrons. The subsequent components help to stop the neutron beam when the samples are changed, to move the sample horizontally, vertically and rotate it, to detect the thermal neutrons by utilization of hi-tech electronics for image processing technique and the development of the real-time imaging system and computer tomography as well as to offer biological protection to personnel. It is possible to develop new applications for nondestructive control in civil and military industry, archaeology, etc. (authors)

 
 
 
 
321

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

International Nuclear Information System (INIS)

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.)

322

Ceramic femoral component fracture in total knee arthroplasty: an analysis using fractography, fourier-transform infrared microscopy, contact radiography and histology.  

Science.gov (United States)

Ceramic components in total knee arthroplasty (TKA) are evolving. We analyze the first case of BIOLOX delta ceramic femoral component fracture. A longitudinal midline fracture in the patellar groove was present, with an intact cement mantle and no bony defects. Fractographic analysis with laser scanning microscopy and white light interferometry showed no evidence of arrest lines, hackles, wake hackles, material flaws, fatigue or crack propagation. Analysis of periprosthetic tissues with Fourier-transform infrared (FT-IR) microscopy, contact radiography, histology, and subsequent digestion and high-speed centrifugation did not show ceramic debris. A macrophage-dominated response was present around polyethylene debris. We conclude that ceramic femoral component failure in this case was related to a traumatic event. Further research is needed to determine the suitability of ceramic components in TKA. PMID:24360338

Krueger, Alexander P; Singh, Gurpal; Beil, Frank Timo; Feuerstein, Bernd; Ruether, Wolfgang; Lohmann, Christoph H

2014-05-01

323

Interactive computer programs in sequence data analysis.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

Jagadeeswaran, P.; Mcguire, P. M.

1982-01-01

324

????????? Analysis of Computer Network Security  

Directory of Open Access Journals (Sweden)

Full Text Available ??????????????????????????????????????????????????????????????????????????????????????????????????????,?????,??????????,??,??,???????????????????????????????????????????????????????????????????????????????Accompanied the rapid expansion of computer networks with a wide range of popularity, on the one hand, it became the basic tools for people to exchange information. Openness, high efficiency and low cost are its benefits. On the other hand, more and more people feel it poses a threat to our information. Computer network security has become a long-term, comprehensive subject. It covers a wide range and various aspects: technology, equipment, management, strategy and man-made. This paper introduced the concept of computer network security and related techniques, such as: data encryption technology, system security technology, firewall technology, and specifically discussed the applications and responses to computer network security.

???

2013-07-01

325

Numerical Analysis of Multiscale Computations  

CERN Document Server

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.

Engquist, Björn; Tsai, Yen-Hsi R

2012-01-01

326

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

Science.gov (United States)

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

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

2014-01-01

327

Time of flight fast neutron radiography  

Science.gov (United States)

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.

Loveman, R.; Bendahan, J.; Gozani, T.; Stevenson, J.

1995-05-01

328

Adjustment computations spatial data analysis  

CERN Document Server

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

Ghilani, Charles D

2011-01-01

329

Neutron capture radiography applied to the investigation of boron-10 biodistribution in animals: improvements in techniques of imaging and quantitative analysis  

International Nuclear Information System (INIS)

Neutron capture radiographies (NCR) allow to get both quantitative and qualitative information on the distribution of 10B in biological samples. Based on the results of the 10B-boronophenylalanine biodistribution in a human ocular melanoma engrafted in the anterior chamber and in various organ of a rabbit immunosuppressed with cyclosporine, an original method of NCR macroscopic imaging with an optical bench which uses the CR 39 nuclear track detector as a light guide is proposed. With this device, the quantitative analysis of the 10B concentration in the sample is simplified, because the track density is easily obtained through photometry. Moreover, the relation between the track density and the local 10B concentration in the sample is reviewed, and a nonlinear regression is proposed which allows to take the track overlapping into account. ((orig.))

330

Radiography at CERN  

CERN Multimedia

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...

HSE Unit

2014-01-01

331

Computer applications for engineering/structural analysis  

Energy Technology Data Exchange (ETDEWEB)

Analysts and organizations have a tendency to lock themselves into specific codes with the obvious consequences of not addressing the real problem and thus reaching the wrong conclusion. This paper discusses the role of the analyst in selecting computer codes. The participation and support of a computation division in modifying the source program, configuration management, and pre- and post-processing of codes are among the subjects discussed. Specific examples illustrating the computer code selection process are described in the following problem areas: soil structure interaction, structural analysis of nuclear reactors, analysis of waste tanks where fluid structure interaction is important, analysis of equipment, structure-structure interaction, analysis of the operation of the superconductor supercollider which includes friction and transient temperature, and 3D analysis of the 10-meter telescope being built in Hawaii. Validation and verification of computer codes and their impact on the selection process are also discussed.

Zaslawsky, M.; Samaddar, S.K.

1991-01-01

332

Bone X-Ray (Radiography)  

Medline Plus

Full Text Available ... the limitations of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) ... diagnosis and disease management. top of page How is the procedure performed? View larger with caption The ...

333

Bone X-Ray (Radiography)  

Medline Plus

Full Text Available ... ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive medical test ... not to expose the fetus to radiation. If an x-ray is necessary, precautions will be taken ...

334

Functioning of industrial radiography services  

International Nuclear Information System (INIS)

The objective of this norm is establish the necessary requirements for the functioning of industrial radiography services, as well as the procedures for acquisition and transfer of radioactive sources and/or X-ray equipments used in industrial radiography

335

Analogue Quantum Computers for Data Analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Analogue computers use continuous properties of physical system for modeling. In the paper is described possibility of modeling by analogue quantum computers for some model of data analysis. It is analogue associative memory and a formal neural network. A particularity of the models is combination of continuous internal processes with discrete set of output states. The modeling of the system by classical analogue computers was offered long times ago, but now it is not very e...

Vlasov, Alexander Yu

1998-01-01

336

Real-time radiography  

International Nuclear Information System (INIS)

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

337

Apparatus for gamma radiography  

International Nuclear Information System (INIS)

The aim of the present standard is to fix the rules for the construction of gamma radiography instrumentation without prejudice to the present regulations. These apparatus have to be fitted with only sealed sources conformable to the experimental standard M 61-002. The present standard agrees with the international standard ISO 3999 of 1977 dealing with the same subject. Nevertheless, it is different on the three main following points: it does not accept the same limits of absorbed dose rates in the air calculated on the external surface of projectors; it precribes tightness, bending, crushing and tensile tests for some components of the gamma radiography it prescribes tests of endurance and resistance to breaking for the locking systems of the gamma radiography apparatus. The present standard also specifies the following points: symbols and indications to put on projectors and on the source-holder; identification of the source contained in the projector; and, accompanying documents. The regulation references are given in annexe

338

Radiography of pressure ulcers  

International Nuclear Information System (INIS)

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.)

339

On computational tools for Bayesian data analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

While Robert and Rousseau (2010) addressed the foundational aspects of Bayesian analysis, the current chapter details its practical aspects through a review of the computational methods available for approximating Bayesian procedures. Recent innovations like Monte Carlo Markov chain, sequential Monte Carlo methods and more recently Approximate Bayesian Computation techniques have considerably increased the potential for Bayesian applications and they have also opened new ave...

Robert, Christian P.; Marin, Jean-michel

2010-01-01

340

Bone X-Ray (Radiography)  

Medline Plus

Full Text Available X-ray (Radiography) - Bone Play Video Clip (00:04:40) Your Radiologist Explains Bone X-ray What is ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

 
 
 
 
341

Bone X-Ray (Radiography)  

Medline Plus

Full Text Available X-ray (Radiography) - Bone Play Video Clip (00:04:40) Your Radiologist Explains Bone X-ray What ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a ...

342

Bone X-Ray (Radiography)  

Medline Plus

Full Text Available X-ray (Radiography) - Bone Play Video Clip (00:04:40) Your Radiologist Explains Bone X-ray What is Bone X-ray ( ... X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive medical ...

343

High-resolution computed tomography versus chest radiography in the diagnosis of interstitial lung disease in systemic sclerosis; Avaliacao da tomografia de alta resolucao versus radiografia de torax na doenca intersticial pulmonar na esclerose sistemica  

Energy Technology Data Exchange (ETDEWEB)

Objective: To compare the accuracy of high-resolution computed tomography (HRCT) with chest radiography in the diagnosis of interstitial lung disease in systemic sclerosis (SSc). Materials And Methods: HRCT scans and chest radiographs in postero-anterior and lateral views were performed in 34 patients with systemic sclerosis, according to the American College of Rheumatology preliminary criteria for the diagnosis of SSc. The prevalence of radiological findings suggestive of interstitial lung disease in SSc seen on both imaging methods was compared. Results: Interstitial disease was observed on HRCT images of 31 patients (91%) and in the chest radiographs of 16 patients (47%). The most frequent findings observed on HRCT were septal lines (74%), honeycombing (56%) and parenchymal bands (26%). Chest radiographs showed reticular areas of attenuation in 11 patients (32%) and parenchymal distortion in 12% of the patients. In 18 patients (53%) with normal chest radiographs HRCT showed septal lines in 55%, ground glass in 44%, honeycombing in 38.5% and cysts in 33%. Conclusion: HRCT is more sensitive than chest radiography in the evaluation of incipient interstitial lung involvement in patients with SSc and can provide a justification for immunosuppressive therapy in patients with early disease. (author)

Azevedo, Ana Beatriz Cordeiro de; Calderaro, Debora; Moreira, Caio [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Hospital das Clinicas. Servico de Reumatologia; Guimaraes, Silvana Mangeon Meirelles [Gerais Univ., Belo Horizonte, MG (Brazil). Hospital das Clinicas. Secao de Tomografia Computadorizada; Tavares Junior, Wilson Campos; Leao Filho, Hilton Muniz; Andrade, Diego Correa de [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Hospital das Clinicas. Servico de Radiologia e Diagnostico por Imagem]. E-mail: wilsontavaresjrmd@yahho.fr; Ferreira, Cid Sergio; Vieira, Jose Nelson Mendes [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Faculdade de Medicina. Dept. de Radiologia

2005-04-01

344

Computer Complex for Analysis of Radiographic Images  

International Science & Technology Center (ISTC)

Research and Development of Soft Hardware Family for Computer Analysis and Evaluation of Radiographs for Assurance a Better Ecological Safety of Oil and Gas Pipelines, Nuclear Power Engineering and Chemical Industry Institutions

345

Uncertainty in radiography  

International Nuclear Information System (INIS)

Uncertainty in measured results is an integral part of measurement. The ISO Guide 25 (1990), the applicable ISO standard for testing and calibrating laboratories, requires one to specify the uncertainty of each measurement, in order to give additional information about the measure and and the quality of the measurement. It is well understood how to calculate the uncertainty for quantitative measurements such as length, temperature and so on, but not for test results as in radiography or other NDT testing methods. This paper describes a study undertaken to calculate uncertainty and to estimate the real sizes of discontinuities observed in radiography. (Author)

346

Present status of structural analysis computer programs  

International Nuclear Information System (INIS)

The computer programs for the structural analysis by finite element method have been used widely, and the authors carried out the bench mark test on the computer programs for finite element method already. As the result, they pointed out a number of problems concerning the use of the computer programs for finite element method. In this paper, the details of their development, the analytical function and the examples of calculation are described centering around the versatile computer programs used for the previous study. As the versatile computer programs for finite element method, ANSYS developed by Swanson Analysis System Co., USA, ASKA developed by ISD, West Germany, MARC developed by MARC Analysis Research Institute, NASTRAN developed by NASA, USA, SAP-4 developed by University of California, ADINA developed by MIT, NEPSAP developed by Lockheed Missile Space Co., BERSAFE developed by CEGB, Great Britain, EPACA developed by Franklin Research Institute, USA, and CREEP-PLAST developed by GE are briefly introduced. As the exampled of calculation, the thermal elastoplastic creep analysis of a cylinder by ANSYS, the elastoplastic analysis of a pressure vessel by ASKA, the analysis of a plate with double cracks by MARC, the analysis of the buckling of a shallow arch by MSC-NASTRAN, and the elastoplastic analysis of primary cooling pipes by ADINA are explained. (Kako, I.)

347

Management Waste Of Of Radiography Of Personal Certification Process  

International Nuclear Information System (INIS)

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

348

Computer aided analysis of rock slope stability  

Science.gov (United States)

A computer program is written in basic language on a micro-computer to carrying out kinematic analysis of rock slope stability. The program is capable of handling plane sliding, wedge sliding and toppling of rock slopes. Applications of the program are demonstrated by examples on opencast mine excavations and highway cuts. The computer output are presented in the form of tables and illustrations for ease of interpretation. As micro-computers are readily available in design offices nowadays, the present work provides an efficient means for engineers to analyse and design rock slope excavations.

Leung, C. F.; Kheok, S. C.

1987-04-01

349

Optimizing digital radiography of children  

International Nuclear Information System (INIS)

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

350

Pet fish radiography: technique and case history reports  

International Nuclear Information System (INIS)

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

351

Distributed computing and nuclear reactor analysis  

International Nuclear Information System (INIS)

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

352

The stationary neutron radiography system  

International Nuclear Information System (INIS)

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

353

Collaboration on neutron radiography between Hanaro and KURRI  

International Nuclear Information System (INIS)

During the outage period of the KUR due to the fuel conversion to the low-enriched uranium (LEU), project research on neutron radiography and activation analysis has been conducted as the joint use program at research reactor HANARO in KAERI. Research results of neutron radiography were partly presented. 1) Void fraction of nitrogen-water two-phase flow in circular small diameter tubes was measured by neutron radiography using NR port at HANARO. A new flow pattern model was proposed and the prediction of the void fraction was well improved. 2) High definition CCD camera for neutron radiography has been developed. An imaging system with a cooled very high resolution CCD camera was chosen and a signal processing electronics circuit was designed for neutron radiography. Driver circuits for the CCD, the mechanical shutter with large aperture size and ADC were located in the camera head. Performance of the camera will be measured at HANARO in 2008. (T. Tanaka)

354

Accelerator-based neutron tomography cooperating with X-ray radiography  

Science.gov (United States)

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.

Kamiyama, Takashi; Tsukui, Daisuke; Sato, Hirotaka; Kiyanagi, Yoshiaki

2011-09-01

355

Comparative Analysis Of Cloud Computing Security Issues  

Directory of Open Access Journals (Sweden)

Full Text Available Almost all the organizations are seriously thinking to adopt the cloud computingservices, seeing its benefits in terms of cost, accessibility, availability, flexibility andhighly automated process of updation. Cloud Computing enhance the current capabilitiesdynamically without further investment. Cloud Computing is a band of resources, applicationsand services. In cloud computing customer’s access IT related services in terms of infrastructure platform and software without getting knowledge of underlying technologies. With the executionof cloud computing, organizations have strong concerns about the security of their data.Organizations are hesitating to take initiatives in the deployment of their businesses due to data security problem. This paper gives an overview of cloud computing and analysis of security issues in cloud computing.

AKRAM MUJAHID

2014-01-01

356

Scanning equalization radiography  

International Nuclear Information System (INIS)

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

357

High definition radiography  

International Nuclear Information System (INIS)

This paper describes the use of small X and gamma ray sources in industrial radiography. The emphasis is on how they can be used in the ''mass production'' situation or when a large number of tube to tubeplate welds are to be inspected

358

New Radiography Techniques  

International Nuclear Information System (INIS)

Improving the quality of radiographic images involves several aspects: the X ray source, the device used to obtain the image, the optical array in the process and the image manipulation. We give a brief and general view of these different aspects and new techniques for radiography

359

Manual on industrial radiography  

International Nuclear Information System (INIS)

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

360

An Analysis of Distributed Computer Network Administration  

Directory of Open Access Journals (Sweden)

Full Text Available Computer Networking is necessary to human beings. Peoples needed to share ideas, research knowledge, and the way of life to their friends. In the modern time, the role of computer networks became dreamy. Analyzing, accessing, sharing and storing of data and information are very easy with help of distributing computer networking. Social networking sites look after human communication in a better manner and create platforms for in agreement individuals to share their thoughts and opinions. There is a massive contribution of computer networking apparatus in the progress which we see today.But when manage computer networking traffic in distributed computer environment, the quality of network connection is challenging task for network Administrator. Computer network properties are depends on different types of applications. Important properties of the quality of network connection are bandwidth, delay and reliability. The network Administrator uses many troubleshooting software to solving network problem regarding the quality of connection.This paper explores different properties for the administration for the distributed computer network environment like techniques for measuring and analyzing the performance. This analysis precious for computer network administrator, who administrating distribute computer network.

Amit Kumar Sahu

2012-03-01

 
 
 
 
361

Computer-based analysis of chromosomes  

Science.gov (United States)

For more than twenty five years it has been attempted to resolve the automated analysis of human chromosomes by machines. In this review about the application of image analysis techniques it will be tried to give a global overview about some important image proces sing and analysis steps in the automated chromosome analysis. The software is included into the commercially available slidebased analysis system SSCAN for IBMPC compatible computers. Chromosome analysis systems have been developed because of the demand of cyto geneticists for a reliable and economic routine method in human cytogenetit 1 aboratories.

Schreiber, Holger; Kinzl, Hans-Peter

1990-11-01

362

DFT computational analysis of piracetam  

Science.gov (United States)

Density functional theory calculation with B3LYP using 6-31G(d,p) and 6-31++G(d,p) basis set have been used to determine ground state molecular geometries. The first order hyperpolarizability (?0) and related properties (?, ?0 and ??) of piracetam is calculated using B3LYP/6-31G(d,p) method on the finite-field approach. The stability of molecule has been analyzed by using NBO/NLMO analysis. The calculation of first hyperpolarizability shows that the molecule is an attractive molecule for future applications in non-linear optics. Molecular electrostatic potential (MEP) at a point in the space around a molecule gives an indication of the net electrostatic effect produced at that point by the total charge distribution of the molecule. The calculated HOMO and LUMO energies show that charge transfer occurs within these molecules. Mulliken population analysis on atomic charge is also calculated. Because of vibrational analysis, the thermodynamic properties of the title compound at different temperatures have been calculated. Finally, the UV-Vis spectra and electronic absorption properties are explained and illustrated from the frontier molecular orbitals.

Rajesh, P.; Gunasekaran, S.; Seshadri, S.; Gnanasambandan, T.

2014-11-01

363

Automating sensitivity analysis of computer models using computer calculus  

International Nuclear Information System (INIS)

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

364

Emergency skull radiography: the effect of restrictive criteria on skull radiography and CT use  

Energy Technology Data Exchange (ETDEWEB)

A prospective study was performed to determine the effect of restrictive criteria on the use of emergency skull radiography and computed tomography (CT) of the head. Emergency skull radiography required the completion of a special requisition form. Emergency CT of the head was done at the request of senior consultants and was available on a full-time basis. Over 1 year, 2758 skull studies were performed, a decrease of 39.1% when compared with the year before restrictive criteria were instituted, during which 4587 skull examinations were done. In the same period, the number of emergency CT scans of the head increased by 45.7%, from 471 in the control year to 686 in the experimental year. With the use of restrictive criteria, a net savings of $164,000 was achieved. Our results suggest that the use of restrictive criteria is a cost-effective means of limiting skull radiography when CT of the head is readily available.

Baker, S.R.; Gaylord, G.M.; Lantos, G.; Tabaddor, K.; Gallagher, E.J.

1985-08-01

365

Emergency skull radiography: the effect of restrictive criteria on skull radiography and CT use  

International Nuclear Information System (INIS)

A prospective study was performed to determine the effect of restrictive criteria on the use of emergency skull radiography and computed tomography (CT) of the head. Emergency skull radiography required the completion of a special requisition form. Emergency CT of the head was done at the request of senior consultants and was available on a full-time basis. Over 1 year, 2758 skull studies were performed, a decrease of 39.1% when compared with the year before restrictive criteria were instituted, during which 4587 skull examinations were done. In the same period, the number of emergency CT scans of the head increased by 45.7%, from 471 in the control year to 686 in the experimental year. With the use of restrictive criteria, a net savings of $164,000 was achieved. Our results suggest that the use of restrictive criteria is a cost-effective means of limiting skull radiography when CT of the head is readily available

366

X-ray detectors for digital radiography.  

Science.gov (United States)

Digital radiography offers the potential of improved image quality as well as providing opportunities for advances in medical image management, computer-aided diagnosis and teleradiology. Image quality is intimately linked to the precise and accurate acquisition of information from the x-ray beam transmitted by the patient, i.e. to the performance of the x-ray detector. Detectors for digital radiography must meet the needs of the specific radiological procedure where they will be used. Key parameters are spatial resolution, uniformity of response, contrast sensitivity, dynamic range, acquisition speed and frame rate. The underlying physical considerations defining the performance of x-ray detectors for radiography will be reviewed. Some of the more promising existing and experimental detector technologies which may be suitable for digital radiography will be considered. Devices that can be employed in full-area detectors and also those more appropriate for scanning x-ray systems will be discussed. These include various approaches based on phosphor x-ray converters, where light quanta are produced as an intermediate stage, as well as direct x-ray-to-charge conversion materials such as zinc cadmium telluride, amorphous selenium and crystalline silicon. PMID:9015806

Yaffe, M J; Rowlands, J A

1997-01-01

367

X-ray detectors for digital radiography  

International Nuclear Information System (INIS)

Digital radiography offers the potential of improved image quality as well as providing opportunities for advances in medical image management, computer-aided diagnosis and teleradiology. Image quality is intimately inked to the precise and accurate acquisition of information from the x-ray beam transmitted by the patient, i.e. to the performance of the x-ray detector. Detectors for digital radiography must meet the needs of the specific radiological procedure where they will be used. Key parameters are partial resolution, uniformity of response, contrast sensitivity, dynamic range, acquisition speed and frame rate. The underlying physical considerations defining the performance of x-ray detectors for radiography will be reviewed. Some of the more promising existing and experimental detector technologies which may be suitable for digital radiography will be considered. Devices that can be employed in full-area detectors and also those more appropriate for scanning x-ray systems will be discussed. These include various approaches based on phosphor x-ray converters, where light quanta are produced as an intermediate stage, as well as direct -ray-to-charge conversion materials such as zinc cadmium telluride, amorphous selenium and crystalline silicon. (author)

368

Comprehensive Optimization Process of Paranasal Sinus Radiography  

Energy Technology Data Exchange (ETDEWEB)

Background: The optimization of radiological examinations is important in order to reduce unnecessary patient radiation exposure. Purpose: To perform a comprehensive optimization process for paranasal sinus radiography at Mikkeli Central Hospital (Finland). Material and Methods: Patients with suspicion of acute sinusitis were imaged with a Kodak computed radiography (CR) system (n=20) and with a Philips digital radiography (DR) system (n=30) using focus-detector distances (FDDs) of 110 cm, 150 cm, or 200 cm. Patients' radiation exposure was determined in terms of entrance surface dose and dose-area product. Furthermore, an anatomical phantom was used for the estimation of point doses inside the head. Clinical image quality was evaluated by an experienced radiologist, and physical image quality was evaluated from the digital radiography phantom. Results: Patient doses were significantly lower and image quality better with the DR system compared to the CR system. The differences in patient dose and physical image quality were small with varying FDD. Clinical image quality of the DR system was lowest with FDD of 200 cm. Further, imaging with FDD of 150 cm was technically easier for the technologist to perform than with FDD of 110 cm. Conclusion: After optimization, it was recommended that the DR system with FDD of 150 cm should always be used at Mikkeli Central Hospital. We recommend this kind of comprehensive approach in all optimization processes of radiological examinations.

Saarakkala, S. (Dept. of Clinical Radiology, Kuopio Univ. Hospital, Kuopio (Finland)); Nironen, K.; Hermunen, H.; Aarnio, J.; Heikkinen, J.O. (Dept. of Radiology, Etel-Savo Hospital District, Mikkeli Central Hospital, Mikkeli (Finland))

2009-04-15

369

Computer aided nonlinear electrical networks analysis  

Science.gov (United States)

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.

Slapnicar, P.

1977-01-01

370

Computational analysis of ramjet engine inlet interaction  

Science.gov (United States)

A computational analysis of a ramjet engine at Mach 3.5 has been conducted and compared to results obtained experimentally. This study focuses on the behavior of the inlet both with and without combustor backpressure. Increased backpressure results in separation of the body side boundary layer and a resultant static pressure rise in the inlet throat region. The computational results compare well with the experimental data for static pressure distribution through the engine, inlet throat flow profiles, and mass capture. The computational analysis slightly underpredicts the thickness of the engine body surface boundary layer and the extent of the interaction caused by backpressure; however, the interaction is observed at approximately the same level of backpressure both experimentally and computationally. This study demonstrates the ability of two different Navier-Stokes codes, namely RPLUS and PARC, to calculate the flow features of this ramjet engine and to provide more detailed information on the process of inlet interaction and unstart.

Duncan, Beverly; Thomas, Scott

1992-01-01

371

Computational aspects of DNA mixture analysis  

DEFF Research Database (Denmark)

Statistical analysis of DNA mixtures for forensic identification is known to pose computational challenges due to the enormous state space of possible DNA profiles. We describe a general method for computing the expectation of a product of discrete random variables using auxiliary variables and probability propagation in a Bayesian network. We propose a Bayesian network representation for genotypes, allowing computations to be performed locally involving only a few alleles at each step. Exploiting appropriate auxiliary variables in combination with this representation allows efficient computation of the likelihood function and prediction of genotypes of unknown contributors. Importantly, we exploit the computational structure to introduce a novel set of diagnostic tools for assessing the adequacy of the model for describing a particular dataset.

Graversen, Therese; Lauritzen, Steffen L.

2014-01-01

372

Industrial radiography on radiographic paper  

International Nuclear Information System (INIS)

An investigation was performed to compare the quality of radiographic paper with that of X-ray film, after a review had been made of the rather scarce literature on the subject. The equipment used throughout the investigation is described, and characteristic curves for Agfa-Gevaert and Kodak papers exposed with different intensifying screens in the low and intermediate voltage range are reproduced. The relative speed, contrast and exposure latitude were computed from these curves. The quality of the radiographic image was checked on U/Al blocks and plates, Al and Fe blocks, and fiber-reinforced composites. Exposure charts for Al and Fe were made for various paper and screen combinations. Both the sharpness of the radiographic image as well as the influence of processing on speed and contrast were checked. Examples are given of the practical application of the paper for radiography of castings, weldings, solderings, assemblies, etc. (author)

373

Diagnostic radiography of the shoulder  

International Nuclear Information System (INIS)

The frequent complaint about 'pain in the shoulder' is so diffuse that it needs exact clinical and differentiated radiographic examination. The diagnosis 'periarthritis humeroscapularis' can only be given after exclusion of ossous, chondral, or capsular lesions, joint disorders, rotator cuff rupture, or constriction of the subacromial space. Subsequent to antero-posterior and axial, sometimes also tangential, radiography, sonographic examination in many cases already yields the significant information. In case of suspected rotator cuff rupture, the diagnosis can be verified by arthrography or NMR imaging, and labrum defects can well be detected by computed arthro-tomography or NMR imaging. Although sometimes laborious, diagnostic radiology yields the information required to select the suitable conservative or surgical treatment. (orig.)

374

ASTEC: Controls analysis for personal computers  

Science.gov (United States)

The ASTEC (Analysis and Simulation Tools for Engineering Controls) software is under development at Goddard Space Flight Center (GSFC). The design goal is to provide a wide selection of controls analysis tools at the personal computer level, as well as the capability to upload compute-intensive jobs to a mainframe or supercomputer. The project is a follow-on to the INCA (INteractive Controls Analysis) program that has been developed at GSFC over the past five years. While ASTEC makes use of the algorithms and expertise developed for the INCA program, the user interface was redesigned to take advantage of the capabilities of the personal computer. The design philosophy and the current capabilities of the ASTEC software are described.

Downing, John P.; Bauer, Frank H.; Thorpe, Christopher J.

1989-01-01

375

Present state of JRR-3M neutron radiography facility in Japan Atomic Energy Research Institute  

International Nuclear Information System (INIS)

The JRR-3M neutron radiography facility was designed and installed from the new viewpoint considering the results of the research on neutron radiography carried out so far by JAERI and the future trend of utilizing neutron radiography, when JRR-3 was reconstructed. It was completed in January, 1991. The JRR-3M neutron radiography facility is ranked as the top class in the world, by fully utilizing the high performance of JRR-3M. Especially, the high neutron flux of more than 105n/cm2/s and the good n/? ratio enable to acquire clear dynamic images in electron photographing method. This facility comprises the thermal neutron radiography and the cold neutron radiography facilities. The basic course on which the design concept was based is explained. Considering the general utilization, the shielding computation and the aseismatic computation were carried out so that the JRR-3M neutron radiography facility can be used safely. The facility is composed of two photographing rooms for thermal neutron radiography, one photographing room for cold neutron radiography, NR casks, an image processor and a dark room. The characteristics of the JRR-3M neutron radiography facility, the state of its utilization and the trend of research and development hereafter are reported. (K.I.)

376

Industrial Radiography Safety in Australia  

International Nuclear Information System (INIS)

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 ded 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 cumbersome and often exceeds the prescribed OH and S single person lifting limits. The role of industrial radiography has expanded to inspect not only welds and castings, so that it now includes inspection of assembled and processed goods ranging from automotive air-bags to canned food. It is also used in security systems at airports and other facilities. Almost all these applications use cabinet systems which are rarely the subject of serious radiation incidents or accidents. Gamma ray inspection no longer uses radium. The most common radio-isotopes in use now are Cobalt 60 and Iridium 192. Their freedom from the need for an electrical power supply; their high radiation energy and the ability to place a source in positions of limited physical access, ensures the ongoing attraction of the method. The useful activity ranges of typical sources vary according to their application and the effect on total inspection costs. Common source activities in Australia range between 185 and 370 GBq for Cobalt 60; and between 1500 and 3700 GBq for Iridium 192. Outside Australia however there are recent reports of routine industrial radiography using more than 5500 GBq of Iridium 192. Thus it can be appreciated that any radiation accidents involving these high activity sources have the potential for significant radiation doses. Personal Dose Data: ARPANSA and its predecessor, the Australian Radiation Laboratory, has been providing a personal radiation monitoring service for some time, and releases a summary report every few years (ARPANSA/TR 139, ARL/TR 121, ARL/TR 107). The selected data shown in Table 2 indicate a downward trend in occupational doses received by industrial radiographers working in open site situations, which are potentially the most hazardous. This trend is encouraging, especially when the number of industrial radiographers is increasing. A comparison of the ARPANSA data indicate that whilst the average Australian industrial radiographer's annual dose is higher than the 400 ?Sv average for industrial radiographers in a d

377

Projection radiography and tomography  

International Nuclear Information System (INIS)

Our program on heavy-ion radiography began soon after heavy ions were accelerated to high energies. Heavy ions are capable of very high electron density discrimination combined with good radial image resolution and low dose. Since heavy-ion beams produce many secondries, plastic nuclear detectors have an advantage for recording heavy-ion images. Projection imaging is now a practical technique that can resolve density differences between normal tissue and tumor tissue in some cases in which X rays could not make a distinction. Initial attempts at heavy-ion tomography also indicate potential for high resolution in this field. The physical basis for heavy-ion radiography and tomographic reconstruction studies are discussed in detail

378

Quantitative film radiography  

Energy Technology Data Exchange (ETDEWEB)

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.

Devine, G.; Dobie, D.; Fugina, J.; Hernandez, J.; Logan, C.; Mohr, P.; Moss, R.; Schumacher, B.; Updike, E.; Weirup, D.

1991-02-26

379

Heavy-ion radiography  

International Nuclear Information System (INIS)

Heavy-particle radiography has clinical potential as a newly developed noninvasive low-dose imaging procedure that provides increased resolution of minute density differences in soft tissues of the body. The method utilizes accelerated high-energy ions, primarily carbon and neon, at the Bevalac accelerator at the Lawrence Berkeley Laboratory. The research program for medicine utilizes heavy-ion radiography for low-dose mammography, for treatment planning for cancer patients, and for imaging and accurate densitometry of skeletal structures, brain and spinal neoplasms, and the heart. The potential of heavy-ion imaging, and particularly reconstruction tomography, is now proving to be an adjunct to existing diagnostic imaging procedures in medicine, both for applications to the diagnosis, management and treatment of clinical cancer in man, and for the early detection of small soft-tissue tumors at low radiation dose

380

Dose in conventional radiography  

International Nuclear Information System (INIS)

It has been pointed out that medical exposures are the most significant sources of exposure to ionizing radiation for the general population. Inside the medical exposures the most important is the X-ray use for diagnosis, which is by far the largest contribution to the average dose received by the population. From all studies performed in radiology the chest radiography is the most abundant. In an X-ray machine, voltage and current are combined to obtain a good image and a reduce dose, however due to the workload in a radiology service individual dose is not monitored. In order to evaluate the dose due to chest radiography in this work a plate phantom was built according to the ISO recommendations using methylmethacrylate walls and water. The phantom was used in the Imaging department of the Zacatecas General Hospital as a radiology patient asking for a chest study; using thermoluminescent dosimeters, TLD 100 the kerma at the surface entrance was determined. (Author)