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1

Analysis of exposure technique in computed radiography  

International Nuclear Information System (INIS)

For proper x-ray data acquisition and image display in computed radiography (CR: Fuji), it is necessary to know the dynamic ranges of the detector and display, and also of the subject being radiographed. The authors developed a computer program that enables measurement of the dynamic range of the subject. In the conventional radiographic techniques, they kept the dynamic range of the subject within the dynamic range of the film by changing the exposure factors. Exposure techniques should be reconsidered to take full advantage of CR, because the images with wide dynamic range show effectiveness of the picture processing, particularly spatial filtering

2

Scale analysis using X-ray microfluorescence and computed radiography  

International Nuclear Information System (INIS)

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. - Highlights: • Qualification of the elements present in scale deposits by SR?XRF. • Analysis of the distribution of the elements in scale samples. • Quantification of the scale layer thickness by computed radiography

3

Is reject analysis necessary after converting to computed radiography?  

Science.gov (United States)

Reject analysis is an accepted standard of practice for quality assurance in conventional radiology. The need for reject analysis has been challenged by the introduction of computed radiography (CR) because of low reported reject rates and because criteria for improperly exposed images were lacking. Most CR systems include quality control (QC) workstations that are capable of modifying the appearance of images before release, and also of deleting poor images before they are analyzed. Texas Children's Hospital has been using computed radiography since October 1995, and now conducts essentially filmless imaging operations using a large-scale picture archival and communications system (PACS) with fourteen CR units. The QC workstation is a key element of our CR operation; however, the extensive software tools of the workstation are limited in terms of avoiding repeated examinations. Neither the QC workstation nor the PACS itself is designed to support reject analysis, so our task was to design a system that accommodates identification, isolation, and archiving of repeated examinations, making use of our electronic imaging systems. We had already developed transcription codes for our radiologist's examination critique, so we adopted these as codes for rejected images. The technologist at the QC workstation appends the critique code to patient demographic information, modifies other fields to indicate that the image is rejected, and archives as usual. Modified routing tables prevent the release of rejected images but ensure they are available for review. Our frequency and reasons for repeated examinations are comparable to other reports of reject analysis in the literature. The most frequent cause of a repeated examination is mis-positioning. The process of developing the method for capturing repeat, collecting the data, and analyzing it is only one-half of the battle; to achieve an improvement in services, it is necessary to feed back the results to management and staff and to implement training as indicated. It is our intention to share our results with PACS and CR vendors in the hope that they will incorporate some mechanisms for reject analysis into the design of their systems. PMID:12105696

Honea, Rosemary; Elissa Blado, Maria; Ma, Yinlin

2002-01-01

4

Comparative study between computed radiography and conventional radiography  

International Nuclear Information System (INIS)

In Industrial Radiography, there are many criteria that need to be considered based on established standards to accept or reject the radiographic film. For conventional radiography, we need to consider the optical density by using the densitometer when viewing the film on the viewer. But in the computed radiography (CR) we need to evaluate and performed the analysis from the quality of the digital image through grey value. There are many factors that affected the digital image quality. One of the factors which are affected to the digital image quality in the image processing is grey value that related to the contrast resolution. In this work, we performed grey value study measurement on digital radiography systems and compared it with exposed films in conventional radiography. The test sample is a steel step wedge. We found out the contrast resolution is higher in Computed Radiography compared with Conventional Radiography. (author)

5

Computational radiology in skeletal radiography  

International Nuclear Information System (INIS)

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

6

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.)

7

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)

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

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 mechanrior 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

10

Fact or fiction: An analysis of the 10 kVp ‘rule’ in computed radiography  

International Nuclear Information System (INIS)

Purpose: To determine whether increasing the tube voltage by 10 kVp whilst reducing the tube current by 50% (10 kVp ‘rule’) produces similar perceptual image quality. Method: 391 matched pairs of anthropomorphic chest phantom X-ray images were produced on a computed radiography (CR) system. Five experienced clinicians graded the images using a 2 alternative forced choice comparison method. Based on acquisition parameters and dose area product (DAP) readings, effective dose (E) was calculated for all images using dose calculation software. Results: Perceptual image quality scores prior to and following application of the 10 kVp ‘rule’ were found have no statistical difference (p > 0.1), indicating that the increase in kVp and reduction in mAs had limited impact on the perceptual image quality. In all cases E reduced, with an average 36% (s.d 7%) after the ‘rule’ had been applied (p < 0.001). Conclusion: Results demonstrate that application of the 10 kVp ‘rule’ significantly reduces E, with no significant reduction in perceptual image quality. Further research should be conducted for a range of examinations using CR and digital radiography (DR) systems

11

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)

12

Standard guide for computed radiography  

CERN Document Server

1.1 This guide provides general tutorial information regarding the fundamental and physical principles of computed radiography (CR), definitions and terminology required to understand the basic CR process. An introduction to some of the limitations that are typically encountered during the establishment of techniques and basic image processing methods are also provided. This guide does not provide specific techniques or acceptance criteria for specific end-user inspection applications. Information presented within this guide may be useful in conjunction with those standards of 1.2. 1.2 CR techniques for general inspection applications may be found in Practice E2033. Technical qualification attributes for CR systems may be found in Practice E2445. Criteria for classification of CR system technical performance levels may be found in Practice E2446. Reference Images Standards E2422, E2660, and E2669 contain digital reference acceptance illustrations. 1.3 The values stated in SI units are to be regarded as the ...

American Society for Testing and Materials. Philadelphia

2010-01-01

13

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

14

Practical application of suspension criteria scenarios in general radiography, computed radiography, digital radiography and fluoroscopy  

International Nuclear Information System (INIS)

Radiological equipment must be assessed against criteria for acceptability to ensure that it meets the minimum standards for patient safety. This assessment is typically led by a medical physicist with input from radiology staff and the equipment supplier. Equipment that does not meet the criteria requires action and may be suspended from clinical use. European Commission report RP 91 will be revised and replaced as RP 162. It has been drawn up to aid medical physicists with the assessment process and provide guidance on suspension levels. This paper details several cases where the criteria in the proposed RP 162 were applied in general radiography, computed radiography, digital radiography and fluoroscopy. The factors considered by the medical physicist and the outcome of each case are presented. The proposed RP 162 report improves on its predecessor and provides a robust set of criteria for ensuring that patient safety within the EU medical exposures framework is optimised. (authors)

15

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

16

Physical aspects of photostimulable phosphor computed radiography  

International Nuclear Information System (INIS)

Currently photostimuable 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 two years the authors have been carrying out a physical evaluation of modern PPCR technology and some 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. 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. (Author)

17

Image characterization of computed radiography  

International Nuclear Information System (INIS)

The digital radiographic image became a reality as of the 80's decade. Since then, several works have been developed with the aim of reducing the exposure time to ionizing radiation obtaining in this way an excellent image quality with a minimum exposure. In the Computerized Radiography, the conventional film is substituted for Image Plate (IP) which consists of a radiosensitive layer of phosphor crystals on a polyester backing plate. The unique design makes it reusable and easy to handle. When exposed, the IP accumulates and stores the irradiated radioactive energy. In order to qualify a computerized radiography system it is necessary to evaluate the Image Plate. In this work it was performed a series of experimental procedures with the aim of evaluating the responses characteristics for different plates. For this purpose it was used a computerized radiographic system CR Tower Scanner - GE, with three different types of IPs, all of them manufactured by GE, whose nomenclatures are IPC, IPX and IPS. It was used the Rhythm Acquire and Review programs for image acquisition and treatment, respectively. (author)

18

Subtraction radiography and computer assisted densitometric analyses of standardized radiographs  

International Nuclear Information System (INIS)

A standardized radiographic series of incrementally increasing alveolar crestal defects in skulls were subjected to analyses by subtraction radiography and computer assisted quantitative densitometric analysis. Subjects were able to detect change using subtraction radiography in alveolar bone defects with bone loss in the range of 1-5 percent as measured by 125I absorptiometry. Quantitative densitometric analyses utilizing radiographic pairs adjusted for differences in contrast (gamma corrected) can be used to follow longitudinal changes at a particular alveolar bone site. Such measurements correlate with change observed by 125I absorptiometry (r=0.82-0.94). (author)

19

Computed radiography for major airway in pediatrics  

International Nuclear Information System (INIS)

This paper shows the efficacy of computed radiography for major airway in pediatrics. For this purpose, we examined 40 children (range 2 weeks to 14 years; mean 2.3 years) using Fuji Computed Radiography (FCR) and radiation dose using pediatric phantom under FCR and conventional film and screen system. In comparison study with FCR and conventional film and screen system, FCR images are superior to conventional system in all cases. Scorings were done for the quality of the image of the pharynx, the trachea, and both main bronchi. In phantom study to check radiation dose, radiation dose could be reduced 1/6 of the value using high speed film and screen and 1/15 of the value using conventional speed film and screen. FCR also showed clear airway images in all cases but technical failure to evaluate the clinical lesion. These results suggest that FCR is the adequate imaging modality to evaluate the major airway in children. (author)

20

Measurement of extrafocal radiation by computed radiography  

International Nuclear Information System (INIS)

Measurement of radiation differences from image data is made possible by computed radiography (CR) based on storage phosphor imaging plates. The photostimulable luminescence (PSL) response is linear in a range greater than four orders of magnitude. Pinhole radiographs of focal and extrafocal radiation obtained by CR were quantitatively analysed using the technique originally introduced in recent scatter studies. No films or hard copies were used in the analysis. The material consisted of 54 images for measurement of the focal peak intensity, and a corresponding set of 54 images obtained at a 250 times greater operating sensitivity for the imaging of the extrafocal emission. The extrafocal-to-focal emission ratio was in the range of 0.001-0.006 depending on the off-focus distance. Because of the relatively large area of origin, exposure resulting from extrafocal radiation is estimated to reach up to 20% of the total radiation dosage. The results are in agreement with previous reports using other techniques and show that CR can also be used in a quantitative manner in this kind of comparative measurement. (author)

 
 
 
 
21

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

International Nuclear Information System (INIS)

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

22

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

International Nuclear Information System (INIS)

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

23

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

International Nuclear Information System (INIS)

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

24

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.)

25

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)

26

A new needle-crystalline computed radiography detector  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The most successful digital radiography detectors to date have been storage phosphor plates used in computed radiography (CR). The detector is cheap, has good producibility, and is robust. Direct radiography (DR) systems are being developed based on flat-panel technology. Better image quality is claimed for some DR systems. On the other hand, DR detectors have low producibility and robustness, and a high price. A new CR detector is being developed at Agfa that combines the advantages of CR an...

Leblans, Paul; Struye, Luc; Willems, Peter

2000-01-01

27

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

28

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)

29

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

30

Noise analysis of a digital radiography system  

International Nuclear Information System (INIS)

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

31

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.ollaboration.

32

a study of computed radiography by whole body CT scanner  

International Nuclear Information System (INIS)

In October, 1975, the first home-made CT unit by Hitachi Ltd. was installed in Fujita Gakuen University Hospital. Since then, the methods to set a level of scan in CT examination have been investigated and reported. First, the slit scanography was discussed, which was used to determine a most adequate level for the examination with a CT scanner. Then, two-dimensional images reconstructed from the data of CT detectors were adopted for clinical use, and the Scoutview of GE CT/T8800 and others have adopted so-called computed radiography (CR) system. In order to improve the quality of CR images and to find a new radiological technique by CT for clinical applications, efforts have been exerted by the hospital. The advantages of CR are as follows. As the digital data have been accumulated and memorized in this system, CR images can be modified in many ways, and displayed on the CRT. The contrast resolution of the system is superior to that of conventional radiography. As the linearity of the detector sensitivity is superior to conventional screen film system, the quantitative analysis of CR images is feasible. CR images enable to confirm the level of scan without moving a patient to another table. The X-ray dose of CR system is reduced to 1/5 as compared with the routine X-ray radiography of skulls and abdomens. The spatial resolution of CT images is insufficient, however. (Kako, I.)

33

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

International Nuclear Information System (INIS)

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

34

Efficacy of skull radiography in relation to computed tomography  

International Nuclear Information System (INIS)

We evaluated the efficacy of skull radiography in relation to computed tomography (CT) in 3050 cases who were clinically suspected of having various organic intracranial diseases. Abnormalitis were detected in 1598 cases (52.4%) by CT, but only in 54 cases by skull radiography (1.8%). The abnormalities detected more easily by skull radiography were those of calvaria including fractures and bone destruction. However, few of them add clinically useful informations to those already obtained by CT. At present CT is almost always performed when an organic intracranial disease is clinically suspected. Obtaining skull radiography routinely in this situation is unnecessary. We conclude that skull radiography should be performed in a few selected cases. (author)

35

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

36

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

37

Nuclear imaging using Fuji Computed Radiography  

International Nuclear Information System (INIS)

We studied the feasibility of the Fuji Computed Radiography system (FCR) in nuclear medicine. The basic principle of the system is the conversion of the X-ray energy pattern into digital signals utilizing scanning laser stimulated luminescence. A Rollo phantom filled with 12 mCi of Tc-99m pertechnetate was used in this study. In imaging by the FCR, a low energy high resolution parallel hole collimator for a gamma camera was placed over the phantom and photons through the collimator were stored on a single imaging plate (IP) or 3 IPs covered by the lead plate, 0.3 mm in thickness. For imaging, it took 30 minutes by a single IP and 20 minutes by 3 IPs with the lead plate respectively. Each image of the phantom by the FCR was compared with that of obtained by a gamma camera. The image by a single IP was inferior in quality than that of by a gamma camera. However using 3 IPs with the lead plate, same quality image as by a gamma camera was obtained. The image by 3 IPs is similar to that of by 3 IPs with the lead plate. Based on the results, we performed liver and lung imaging by FCR using 3 IPs. The imaging time is twenty minutes. The images obtained with FCR are as good as the scinticamera image. However it has two major flawes in that the sensitivity is poor and the imaging time is long. Furthermore, at present this method can only be employed for static imaging. However we feel that future improvements in the FCR system will overcome these problems. (author)rcome these problems. (author)

38

Image feature analysis and computer-aided diagnosis in digital radiography: automated delineation of posterior ribs in chest images.  

Science.gov (United States)

In order to facilitate computerized quantitative analysis of digital chest radiographs, an automated method for accurate delineation of posterior ribs in frontal chest images is being developed. This method is based on an analysis of vertical profiles in the lung regions and a statistical analysis of edge gradients and their orientations in small selected regions-of-interest (ROIs). A shift-variant function is fitted to vertical profiles to obtain initial estimates of locations of rib edges. Rib edges are then determined more accurately by analyzing cumulative edge gradients and their orientations in small ROIs that are located adjacent to the initially estimated edges. The present computerized method can achieve a good agreement between the detected and the actual rib structures for posterior ribs in 74% of 50 cases examined. This suggests that automated detection of posterior ribs by a computerized method is feasible, and may be useful for computer-aided diagnostic schemes in the chest. PMID:1961161

Sanada, S; Doi, K; MacMahon, H

1991-01-01

39

Computer-aided diagnosis in chest radiography. Study of the effect caused by varied image quality on texture analysis  

International Nuclear Information System (INIS)

Computer-aided diagnosis (CAD) system has been developing in the field of medical imaging. As CAD becomes more common in diagnostic radiology, it is expected that diagnostic performance will be improved. In actual use, however, the results of CAD might be affected by the quality of images, which are obtained under different exposure conditions and/or with differing devices. In this study, we investigated the effect of varied image quality on the results of texture analysis, a method developed by Katsuragawa, et al. and used in CAD for the detection of interstitial lung disease. To provide samples of varying image quality, we obtained images using various exposure doses and scatterer thicknesses. It was found that texture analysis was affected by differences in scatterer thickness. (author)

40

Computation of air kerma rate around an industrial radiography source  

International Nuclear Information System (INIS)

Use of Iridium-192 and Cobalt-60 sources in Industrial Radiography has recorded a steep rise in the last three decades in India. There are about 425 institutions in possession of 1100 radiography equipment's. Widespread use of these sources call for meticulous radiation safety programme in the use of these sources. A gamma radiography exposure device comprises of adequately shielded source holder assembly and accessories such as remote control cable and guide tube with suitable mechanism to facilitate radiation exposure in a safe manner for industrial radiography work. The source holder assembly is driven out of the shielded container through the guide tube by means of a suitable drive mechanism. Various built-in design safety features are incorporated in these devices to ensure safe operation and to avoid untoward incidents. In spite of effective regulatory control, accidents may take place. For example, an accident situation may arise due to decoupling of the source assembly which may lead to the source falling on the ground and consequent exposure of people around the source and also the personnel involved in source retrieval operations. A knowledge of the air kerma distribution around the source will be of use in estimating the doses to the concerned personnel. This paper discusses the air kerma distribution around and iridium-192 radiography source computed using Monte Carlo method

 
 
 
 
41

A new needle-crystalline computed radiography detector.  

Science.gov (United States)

The most successful digital radiography detectors to date have been storage phosphor plates used in computed radiography (CR). The detector is cheap, has good producibility, and is robust. Direct radiography (DR) systems are being developed based on flat-panel technology. Better image quality is claimed for some DR systems. On the other hand, DR detectors have low producibility and robustness, and a high price. A new CR detector is being developed at Agfa that combines the advantages of CR and DR. It is a storage phosphor plate made up of needle-shaped crystals. The phosphor efficiently converts absorbed x-ray quanta into photostimulable centers for efficient read out. It has a large dynamic range and its emission is efficiently detected with both photomultiplier tube (PMT) and charge coupled device (CCD). It is shown that CR systems based on the new detector offer image quality that matches that of the best DR systems. PMID:10847378

Leblans, P; Struye, L; Willems, P

2000-05-01

42

Reject analysis in direct digital radiography  

International Nuclear Information System (INIS)

Background. Reject analysis can be used as a quality indicator, and is an important tool in localizing areas where optimization is required. Reducing number of rejects is important yielding reduced patient exposure and increased cost-effectiveness. Purpose. To determine rejection rates and causes in direct digital radiography. Material and Methods. Data were collected during a three-month period in spring 2010 at two direct digital laboratories in Norway. All X-ray examinations, types, numbers, and reasons for rejections were obtained using automatic reject analysis software. Thirteen causes for rejection could be selected. Results. Out of the 27,284 acquired images, 3206 were rejected, yielding an overall rejection rate of 12%. Highest rejection rates were found for examination of knees, shoulders, and wrist. In all, 77% of the rejected images arose from positioning errors. Conclusion. An overall rejection rate of 12% indicates a need for optimizing radiographic practice in the department

43

Image feature analysis and computer-aided diagnosis in digital radiography. I. Automated detection of microcalcifications in mammography.  

Science.gov (United States)

We have investigated the application of computer-based methods to the detection of microcalcifications in digital mammograms. The computer detection system is based on a difference-image technique in which a signal-suppressed image is subtracted from a signal-enhanced image to remove the structured background in a mammogram. Signal-extraction techniques adapted to the known physical characteristics of microcalcifications are then used to isolate microcalcifications from the remaining noise background. We employ Monte Carlo methods to generate simulated clusters of microcalcifications that are superimposed on normal mammographic backgrounds. This allows quantitative evaluation of detection accuracy of the computer method and the dependence of this accuracy on the physical characteristics of the microcalcifications. Our present computer method can achieve a true-positive cluster detection rate of approximately 80% at a false-positive detection rate of one cluster per image. The potential application of such a computer-aided system to mammographic interpretation is demonstrated by its ability to detect microcalcifications in clinical mammograms. PMID:3626993

Chan, H P; Doi, K; Galhotra, S; Vyborny, C J; MacMahon, H; Jokich, P M

1987-01-01

44

Computer-aided Recognition of Emphysema on Digital Chest Radiography  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

2010-01-01

45

Application of computed radiography for power plant tube  

International Nuclear Information System (INIS)

For radiographic examination, it is imperative that the film characteristics be determined so that optimal test conditions, and the result thereof, can be verified by analyzing the film values with regard to different radiation sources, and for standardizing the characteristics such as sensitivity, exposure thickness range (latitude) and maximum and minimum exposure dose, The research presented in this paper was aimed at evaluating the radioactive sensitivity characteristics of the Image Plate, in lieu of film, as used in Computer Radiography for various radiation sources, in order to apply this newly developed technology in other industrial fields, and in particular, the Power Plant industry. Several possibilities and improvements were discovered with the substitution of Computer Radiography for Conventional Film Radiographic Test.

46

Physical image quality of computed radiography in mammography system  

International Nuclear Information System (INIS)

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

47

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.

2001-12-01

48

Computer-aided recognition of emphysema on digital chest radiography  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2011-11-15

49

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

International Nuclear Information System (INIS)

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

50

AEC set-up optimisation with computed radiography imaging  

International Nuclear Information System (INIS)

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

51

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-08-15

52

Advances in computed radiography systems and their physical imaging characteristics  

International Nuclear Information System (INIS)

Radiological imaging is progressing towards an all-digital future, across the spectrum of medical imaging techniques. Computed radiography (CR) has provided a ready pathway from screen film to digital radiography and a convenient entry point to PACS. This review briefly revisits the principles of modern CR systems and their physical imaging characteristics. Wide dynamic range and digital image enhancement are well-established benefits of CR, which lend themselves to improved image presentation and reduced rates of repeat exposures. However, in its original form CR offered limited scope for reducing the radiation dose per radiographic exposure, compared with screen film. Recent innovations in CR, including the use of dual-sided image readout and channelled storage phosphor have eased these concerns. For example, introduction of these technologies has improved detective quantum efficiency (DQE) by approximately 50 and 100%, respectively, compared with standard CR. As a result CR currently affords greater scope for reducing patient dose, and provides a more substantive challenge to the new solid-state, flat-panel, digital radiography detectors

53

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

54

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 andThe computer-aided procedure is simple and inexpensive, and permits quick recognition of emphysema on digital chest radiographs.

55

Computers in dental radiography: a scenario for the future  

International Nuclear Information System (INIS)

The recent emergence of cost-effective computing power makes it possible to integrate sophisticated data-sampling and image-interpretation techniques into dental radiography for the first time. A prototype system is being developed to permit clinical information expressed in three dimensions--plus time--to be made visible almost instantly. The associated X-ray dose for a complete three-dimensional survey of a selected dental region is predicted to be less than that required for a single conventional periapical radiograph exposed on D-speed film

56

Clinical experience with computed radiography in pediatric radiology  

International Nuclear Information System (INIS)

After the installation of a computed radiographic system (FCR-101) in the pediatric radiology department, a study was developed to evaluate this new modality in comparison with conventional radiography. Since October 1985, 80% of the examinations (average, 200 procedures per week) have been performed with the FCR, which works continuously and displays the image either on a hard copy or on high-resolution television monitors. Fifty percent of examinations have been performed to image the chest, 20% to image the abdomen, 13% to image the extremities, 12% to image the skull, and 5% to image other areas

57

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)

58

Magnetic resonance imaging and computed radiography in Achilles tendon rupture  

International Nuclear Information System (INIS)

Magnetic Resonance Imaging (MRI) and Computed Radiography (CR) were performed in 15 patients with complete Achilles tendon rupture who were treated conservatively without surgery. MRI was obtained using Toshiba MRT 50 A superconductive machine, operaing at 0.5 Tesla. CR was performed by CR-101, Fuji Medical System. In fresh cases, ruptured tendons showed intermediate signal intensity on T1-weighted images and high intensity on T2-weighted images. Thickening of the tendon was observed in all cases except in very acute stage. Configuration of thickend tendons tends to be dumbbell shape in subacute stage and fusiform in chronic stage of more than six months after the initial trauma. In cases which showed high signal intensity at the ruptured area both on T1 and T2 weighted images, migration of fat into the sapces between the ruptured tendons was considered to be the major source of increased signal intensity. Computed radiography showed thickening of the tendon, blurring of anterior margin of the tendon, and decreased translucency of pre-Achilles fat pad. However, MRI better demonstrated the details of ruptured tendons when compared to CR, and thought to be an usefull way of following up the healing process of the ruptured tendon to facilitate more reasonable judgement of the time of removing plaster casts and stating exercise. (author)

59

A computed tomography implementation of multiple-image radiography  

International Nuclear Information System (INIS)

Conventional x-ray computed tomography (CT) produces a single volumetric image that represents the spatially variant linear x-ray attenuation coefficient of an object. However, in many situations, differences in the x-ray attenuation properties of soft tissues are very small and difficult to measure in conventional x-ray imaging. In this work, we investigate an analyzer-based imaging method, called computed tomography multiple-image radiography (CT-MIR), which is a tomographic implementation of the recently proposed multiple-image radiography method. The CT-MIR method reconstructs concurrently three physical properties of the object. In addition to x-ray attenuation, CT-MIR produces volumetric images that represent the refraction and ultrasmall-angle scattering properties of the object. These three images can provide a rich description of the object's physical properties that are revealed by the probing x-ray beam. An imaging model for CT-MIR that is based on the x-ray transform of the object properties is established. The CT-MIR method is demonstrated by use of experimental data acquired at a synchroton radiation imaging beamline, and is compared to the pre-existing diffraction-enhanced imaging CT method. We also investigate the merit of an iterative reconstruction method for use with future clinical implementations of CT-MIR, which we anticipate would be photon limited

60

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

International Nuclear Information System (INIS)

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

 
 
 
 
61

Accuracy of cone beam computed tomography, intraoral radiography, and periodontal probing for periodontal bone defects measurement  

Directory of Open Access Journals (Sweden)

Full Text Available "nBackground and Aims: Cone beam computed tomography (CBCT produces high-quality data about diagnosis and periodontal treatment. To date, there is not enough research regarding periodontal bone measurement using CBCT. The aim of this study was to compare the accuracy of CBCT in measuring periodontal defects to that of intraoral radiography and probing methods."nMaterials and Methods: Two-hundred and eighteen artificial osseous defects (buccal and lingual infrabony, interproximal, horizontal, crater, dehiscence and fenestration defects were created on 13 mandibles of dry skulls. The mandibles were put into a plexiglass box full of water to simulate soft tissue. CBCT images, radiographic images taken with parallel technique and direct measurements using a WHO periodontal probe were recorded and compared to a standard reference (digital caliper. Inter and intra observe consistencies were assessed using Intra class correlation coefficient and pearson correlation."nResults: Inter and intra observer consistencies were high for CBCT and probing methods (ICC- Intra class correlation coefficient>88%, but moderate for intraoral radiography (ICC-Intra class correlation coefficient > 54%. There were not any significant differences between observers for all techniques (P>0/05. According to paired T-test analysis, mean difference for CBCT technique (0.01 mm was lower than that for probing (0.04 mm and radiography (0.62 mm. CBCT was able to measure all kinds of lesions, but radiography could not measure defects in the buccal and lingual sites."nConclusion: All three modalities are useful for identifying periodontal defects. Compared to probing and radiography, the CBCT technique has the most accuracy in measuring periodontal defects.

Eskandarlo A

2011-02-01

62

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

63

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.

64

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

65

Paediatric entrance doses from exposure index in computed radiography  

International Nuclear Information System (INIS)

Over the last two years we have evaluated paediatric patient doses in projection radiography derived from exposure level (EL) in computed radiography (CR) in a large university hospital. Entrance surface air kerma (ESAK) for 3501 paediatric examinations was calculated from the EL, which is a dose index parameter related to the light emitted by the phosphor-stimulable plate, archived in the Digital Imaging and Communications in Medicine (DICOM) header of the images and automatically transferred to a database using custom-built dedicated software. Typical mean thicknesses for several age bands of paediatric patients was estimated to calculate ESAK from the EL values, using results of experimental measurements with phantoms for the typical x-ray beam qualities used in paediatric examinations. Mean/median ESAK values (in ?Gy) for the age bands of <1 year, 1-5 years, 6-10 years and 11-15 years have been obtained for chest without a bucky: 51/41, 57/34, 91/54 and 122/109; chest with a bucky (for only the last three age bands): 114/87, 129/105 and 219/170; abdomen: 119/91, 291/225, 756/600 and 1960/1508 and pelvis: 65/48, 455/314, 943/707 and 2261/1595. Sample sizes of clinical images used for the (indirect) measurements were 1724 for chest without a bucky, 799 for chest with a bucky, 337 for abdomen and 641 for pelvis. The methodology we describe could be applicable to other centres using CR as an imaging modality for paediatrics. Presently, this method is the only practicresently, this method is the only practical approach to automatically extract parameters contained in the DICOM header, for the calculation of patient dose values for the CR modality

66

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

International Nuclear Information System (INIS)

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

67

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)

68

Radiogenic cancer induction associated with spinal radiography: a quantitative analysis  

International Nuclear Information System (INIS)

Computations of organ-specific radiation absorption by lung, breast, thyroid, active bone marrow and uterine tissues are used to rank sectional and full spine radiographic procedures according to their potentials for cancer induction. Assuming that the dose-effect relationship of radiation damage is linear and lacks a threshold effect, the prospective and retrospective carcinogenicities of commonly ordered spinal series are estimated. Cervical radiography is demonstrated to pose the least hazard to the patient, while full spine and lumbar (five views) procedures have the greatest. Organs most at risk as a result of spinal radiography are lung (thoracic and full spine), colon (lumbar and full spine), breast (thoracic and full spine), and prostate (full spine and lumbar)

69

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)

70

Use of computed radiography in the study of an historic painting.  

Science.gov (United States)

The authors demonstrate the use of radiography in the investigation of an historic painting and describe the potential benefits of computed radiography compared with conventional screen-film radiography. The subject for the comparison was a 16 x 19-foot oil-on-canvas painting, Scipio Africanus Freeing Massiva, by Giovanni Battista Tiepolo. Radiographs of the painting were obtained by using a portable, industrial radiographic unit and both conventional screen-film and photostimulable phosphor plate cassettes. For this investigation, computed radiography had a number of advantages over screen-film radiography, largely due to its wider dynamic range and its capabilities for enhancing the digital images with image processing tools such as magnification, edge enhancement, colorization, and airbrushing. The ability to electronically combine images from the large painting into a single composite image file was extremely valuable, as this technique was much less cumbersome and resulted in much higher quality composite images than could be achieved with conventional radiography. An additional advantage of computed radiography includes the capability to easily archive and transmit these images in a digital format for subsequent review. PMID:9397460

Reiner, B I; Siegel, E L; French, K J; Dentry, R S; Mazan, W T; Maroney, M J

1997-01-01

71

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

72

Temporal digital subtraction radiography with a personal computer digital workstation  

International Nuclear Information System (INIS)

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

73

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-12-01

74

Human performance analysis of industrial radiography radiation exposure events  

International Nuclear Information System (INIS)

A set of radiation overexposure event reports were reviewed as part of a program to examine human performance in industrial radiography for the US Nuclear Regulatory Commission. Incident records for a seven year period were retrieved from an event database. Ninety-five exposure events were initially categorized and sorted for further analysis. Descriptive models were applied to a subset of severe overexposure events. Modeling included: (1) operational sequence tables to outline the key human actions and interactions with equipment, (2) human reliability event trees, (3) an application of an information processing failures model, and (4) an extrapolated use of the error influences and effects diagram. Results of the modeling analyses provided insights into the industrial radiography task and suggested areas for further action and study to decrease overexposures

75

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)

76

Daily quality control in computed radiography mammography using the manufacturer phantom  

Energy Technology Data Exchange (ETDEWEB)

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)

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

2011-07-01

77

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 experimach 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

78

Single-exposure dual-energy digital radiographic method with a storage phosphor computed radiography system  

International Nuclear Information System (INIS)

A plane-projection, single-exposure, dual-energy computed radiography method that uses a storage phosphor/interdetector filter sandwich has recently begun to be used in clinical evaluation of solitary pulmonary nodule (SPN) calcium content and rib lesions. The performance of the singular value decomposition algorithm is compared with other algorithms, along with analysis of the effect of bit depth on accuracy and noise. Results of requisite predecomposition image processing are stated, as are scatter rejection requirements necessitating crossed 12:1 grids. Computer simulation resulted in the following optimal factors for detection of SPNs: 100 kVp and 0.015-cm tin interdetector filter, yielding 23-mR surface exposure and 0.26-mGy absorbed dose

79

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

80

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

 
 
 
 
81

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

82

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

83

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

84

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

International Nuclear Information System (INIS)

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

85

Radiography and bone scintigraphy in multiple myeloma: a comparative analysis  

International Nuclear Information System (INIS)

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

86

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

87

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

88

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)

89

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

International Nuclear Information System (INIS)

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

90

Comparative dosimetry of dental cone beam computed tomography, panoramic radiography, and multislice computed tomography  

International Nuclear Information System (INIS)

The aim of this study was to compare the effective organ doses from cone beam computed tomography (CBCT), multislice computed tomography (MSCT), and panoramic radiography. The tissue-absorbed doses for the Kodak 9500 CBCT system, NewTom FP CBCT system, Morita Veraviewepocs panoramic X-ray device, and Somatom Sensation 16 MSCT system were calculated using thermoluminescent dosimeter chips placed at selected locations on a radiation analog dosimetry phantom. The tissue weighting factors recommended by the International Commission on Radiological Protection in 2007 were used to obtain effective doses. The effective doses from the CBCT systems were 118.65, 84.45, and 75.43 ?Sv for the Kodak 9500 large field of view (FOV), NewTom FP, and Kodak 9500 medium FOV, respectively. The effective doses were 11.37 ?Sv for the panoramic X-ray examination, 583.73 ?Sv for the MSCT ''Dental'' protocol, and 1983.89 ?Sv for the MSCT ''NeckThinSlice'' protocol. The doses from CBCT are not sufficiently low to allow its use as a routine imaging technique instead of panoramic radiography. The FOV size should be chosen carefully to prevent excessive exposure of the patient to radiation. The use of MSCT in dentistry is associated with much radiation and should be avoided in cases where CBCT is adequate for 3D evaluation. (author)

91

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

92

Cholesteatoma: computed tomography and radiography in a dog  

International Nuclear Information System (INIS)

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

93

Anomalous pulmonary venous drainage shown by duplex sonography, computed tomography, and plain radiography.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In a patient with the scimitar syndrome duplex Doppler sonography was used to show the point of entry of the abnormal pulmonary vein into the inferior vena cava to determine blood flow. Chest radiography and computed tomography also showed the vein descending to the diaphragm.

Huebsch, P.; Neuhold, A.; Mayr, H.; Glogar, D.

1989-01-01

94

First Results and Realization Status of a Proton Computed Radiography Device  

International Nuclear Information System (INIS)

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

95

Imaging suspected cervical spine injury: Plain radiography or computed tomography? Systematic review  

International Nuclear Information System (INIS)

Aim: (1) to establish which modality offers the greatest accuracy in the detection of cervical spine injury (CSI) Following trauma: plain radiography or computed tomography (CT), and (2) make an evidence-based recommendation for the initial imaging modality of choice. Method: A systematic literature review was performed to identify primary research studies which compare the diagnostic accuracy of plain radiography and CT with the results of a reference standard in the detection of CSI. A search of MEDLINE, EMBASE, CINAHL, Science Direct and Pubmed Central databases was conducted. Results: Ten studies were identified. Critical appraisal identified limitations among all studies. There was heterogeneity in the sensitivity estimates for plain radiography, whereas estimates for CT were consistently high. Examination of the reported sensitivities shows that CT outperforms plain radiography in the detection of CSI. Conclusion: CT is superior to plain radiography in the detection of CSI. However, the optimal imaging strategy depends on the patients' relative risk of injury. If at high-risk cervical CT is indicated. If at low-risk the increased cost and radiation exposure mean that screening CT may not be warranted, good-quality plain radiographs are sufficient.

96

Imaging suspected cervical spine injury: Plain radiography or computed tomography? Systematic review  

Energy Technology Data Exchange (ETDEWEB)

Aim: (1) to establish which modality offers the greatest accuracy in the detection of cervical spine injury (CSI) Following trauma: plain radiography or computed tomography (CT), and (2) make an evidence-based recommendation for the initial imaging modality of choice. Method: A systematic literature review was performed to identify primary research studies which compare the diagnostic accuracy of plain radiography and CT with the results of a reference standard in the detection of CSI. A search of MEDLINE, EMBASE, CINAHL, Science Direct and Pubmed Central databases was conducted. Results: Ten studies were identified. Critical appraisal identified limitations among all studies. There was heterogeneity in the sensitivity estimates for plain radiography, whereas estimates for CT were consistently high. Examination of the reported sensitivities shows that CT outperforms plain radiography in the detection of CSI. Conclusion: CT is superior to plain radiography in the detection of CSI. However, the optimal imaging strategy depends on the patients' relative risk of injury. If at high-risk cervical CT is indicated. If at low-risk the increased cost and radiation exposure mean that screening CT may not be warranted, good-quality plain radiographs are sufficient.

Cain, Gavin [Diagnostic Radiographer, Colchester Hospital University NHS Foundation Trust, Colchester General Hospital, Turner Road, Colchester, CO4 5JL Essex (United Kingdom)], E-mail: gavincain8@hotmail.com; Shepherdson, Jane; Elliott, Vicki; Svensson, Jon [Faculty of Health and Social Care, Anglia Ruskin University, East Road, Cambridge, CB1 9PT Cambridgeshire (United Kingdom); Brennan, Patrick [UCD School of Medicine and Medical Sciences, Health Science Building, Belfield, Dublin 4 (Ireland)

2010-02-15

97

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

International Nuclear Information System (INIS)

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

98

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

99

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.)

100

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)

 
 
 
 
101

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

International Nuclear Information System (INIS)

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

102

Automatic measurement system for congenital hip dislocation using a computed radiography  

International Nuclear Information System (INIS)

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

103

Radiography, ultrasonography and computed tomography of the dromedary camel tarsus (One humped camel)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The dromedary camel has a very high economic importance in the Arabic countries. Nevertheless, there is a very little background literature on the use of ultrasound (US) and computed tomography (CT) in dromedaries in comparison to other domestic and farm animal species. Therefore, the tarsal region of six cadaver limbs, obtained from three orthopedic disease free dromedary camels, was evaluated via radiography, US and CT. The limbs were frozen and sectioned transversely, sagittaly and dorsall...

Hagag, Usama

2013-01-01

104

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this study was to develop a homemade phantom for quantitative quality control in chest computed radiography (CR). The phantom was constructed from copper, aluminium, and polymenthylmethacrylate (PMMA) plates as well as Styrofoam materials. Depending on combinations, the literature suggests that these materials can simulate the attenuation and scattering characteristics of lung, heart, and mediastinum. The lung, heart, and mediastinum regions were simulated by 10 mm x 10 mm x 0.5 mm...

Muhogora Wilbroad; Padovani Renato; Msaki Peter

2011-01-01

105

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

International Nuclear Information System (INIS)

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

106

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)

107

Computed radiography and the workstation in a study of the cervical spine. Technical and cost implications  

International Nuclear Information System (INIS)

To demonstrate the advantages of computed radiography and the workstation in assessing the images acquired in a study of the cervical spine. Lateral projections of cervical spine obtained using a computed radiography system in 63 ambulatory patients were studied in a workstation. Images of the tip of the odontoid process. C1-C2, basion-opisthion and C7 were visualized prior to and after their transmission and processing, and the overall improvement in their diagnostic quality was assessed. The rate of detection of the tip of the odontoid process, C1-C2, the foramen magnum and C/ increased by 17,6, 11 and 14 percentage points, respectively. Image processing improved the diagnostic quality in over 75% of cases. Image processing in a workstation improved the visualization of the anatomical points being studied and the diagnostic quality of the images. These advantages as well as the possibility of transferring the images to a picture archiving and communication system (PACS) are convincing reasons for using digital radiography. (Author) 7 refs

108

Computed tomography and plain radiography in experimental fracture healing  

International Nuclear Information System (INIS)

We evaluated the relative contribution of plain radiographs and computed tomography to the assessment of fracture healing under experimental circumstances. In 15 sheep, we performed midshaft femoral osteotomies and internal fixation of the resultant segmental fractures. Radiographs were obtained preoperatively and immediately postoperatively. Animals were sacrificed at 3 weeks, 6 weeks, 12 weeks, 24 weeks, and 36 weeks after surgery, and the femoral specimens radiographed. After removal of the internal fixation devices, computed tomographic scans of the specimens were performed. Computed tomography may be of value in the evaluation of fractures of long bones in those cases in which clinical examination and plain radiographs fail to give adequate information as to the status of healing. (orig./SHA)

109

[Clinical efficacy of image processing of grid detection and suppression (GDS) in computed radiography].  

Science.gov (United States)

In projection radiography, stationary grids are indispensable accessories to the improvement of diagnostic imaging. On the other hand, they are becoming one of the issues facing digital image processing. The lead foil that composes the grid can produce moiré on printed films and monitors according to the sampling interval at which the image is read by computed radiography (CR), creating a major obstacle to diagnosing images. The subject of this study on Grid Detection and Suppression (GDS) was the development of comprehensive image-processing software to detect and suppress grid lines automatically. Our results showed that applying GDS parameters 3 approximately 5 could provide a sufficient effect on suppression with little impact on images through the use of a multi-purpose grid (grid ratio 8:1, density 34 lp/cm) for general purposes. In projection radiography, it is expected that soft copy diagnosis will increase because the digital transition is proceeding, and the establishment of high-speed networks is becoming easier. Therefore, the digital environment is expected to improve and the choice of grids and monitors to expand, by using software such as GDS that does not require special skills. PMID:16132035

Kato, Motoaki; Nishimura, Sachie; Okamoto, Takahide; Vanmetter, Richard L; Wang, Xiaohui; Ichiji, Hiroshi; Sawai, Miho; Kiyooka, Makoto; Ikegami, Yuko

2005-08-20

110

Preliminary clinical evaluation of computer-aided diagnosis in digital chest radiography  

International Nuclear Information System (INIS)

We are developing computer-aided diagnosis (CAD) schemes for chest radiography with which to alert radiologists to possible lesions, and thus potentially improve diagnostic accuracy. Although preliminary results of individual CAD schemes have been encouraging, CAD is still at an early stage of its development. Therefore, we applied our CAD programs in a clinical environment and evaluated its potential usefulness and limitations. CAD programs including automated detection of cardiomegaly, analysis of interstitial infiltrates, and detection of lung nodules were applied to 310 consecutive chest radiographs. CAD results for cardiomegaly and interstitial infiltrates were evaluated subjectively by radiologists and physicists for clinical accuracy and technical problems, respectively, depending on the correspondence of the CAD output to the nature and location of important findings influencing the radiologic diagnosis. CAD results for lung nodules were evaluated objectively by taking into account the number of false positives and true positives. For detection of cardiomegaly, 71% of evaluated cases were judged to be acceptably accurate in terms of clinical accuracy. For analysis of focal and diffuse interstitial infiltrates, 87% and 61% were acceptably accurate, respectively. For detection of lung nodules, 61% were acceptably accurate. More than 70% of CAD output was judged to be possibly accurate in terms of technical aspects. Technical problems were related to failure to dical problems were related to failure to detect subtle abnormalities and the occurrence of false positives caused by normal anatomical structures. We believe that CAD has the potential to be a valuable aid for radiologists in clinical practice, if certain technical problems can be overcome and if optimal operating points can be defined for clinical use

111

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

International Nuclear Information System (INIS)

Objective: To compare the image quality, radiation dose and diagnostic accuracy on film-screen, digital radiography (DR) and computed radiography (CR) mammography. Methods: Three different kinds of mammography machines (film-screen, DR and CR) were tested to make sure they were qualified and comparable. Radiographs were taken on Mammo-152 phantom and ACR phantom using film- screen, DR and CR systems with the same radiation dose. Next, radiographs were taken on two phantoms using DR and CR systems with classic mode or AEC and the radiation dose was recorded. The images were numbered and scored by eight independent experienced radiologists under the same reading condition according to ACR method. Statistics was performed with the randomized complete-block design variance analysis. The diagnostic accuracy of three kinds of mammography methods were compared with Kappa test in clinical cases who had pathologic results. Results: The spatial resolution of film-screen system was the highest (7.0-8.0 Lp/mm) and that of CR was the lowest (2.5 Lp/mm). When the radiation dose was increased (27.0%-30.0%), the resolution was improved with DR (+11.0%) but almost no change with CR (+1.5%). The radiation dose of DR was the lowest on ACR phantom. The delineation of mass was better on film-screen than on CR, but the delineation of fibers and speck was better on CR. When the radiation dose of CR was increased (25.0%), the delineation of fibers and speck on CR was similar to that on DR and the delineation of mass was similar to that on film-screen. There was a good correlation between the mammography diagnosis and pathological results (film-screen is 50/56, DR is 83/90 and CR is 61/69, P0.75). The diagnostic accuracy of three mammography systems had no statistical difference [film-screen 89.3% (50/56), DR 92.2% (83/90) and CR 88.4% (61/69 ), Pearson ?2=0.722, P=0.697]. Conclusion: Film/screen system has the highest space resolution and DR has the lowest radiation dose. Three mammography systems have the same diagnostic accuracy for breast disease. (authors)

112

Resolution enhancement of computed radiography images using two orthogonal tilts  

Science.gov (United States)

Limitations to the spatial resolution of current digital x-ray systems are bounded by the physical characteristics of the xray detector. However, the need to image smaller structures provides motivation to develop high-resolution x-ray detector systems for use with computed radiographic, and tomographic x-ray systems. We report the implementation of a tilted detector technique (TDT) to attain near isotropic resolution enhancement by combining two orthogonal image views, acquired with existing detector hardware tilted at a fixed angle. Images were acquired using a ceiling-mounted x-ray unit (Proteus XR/a, GE Medical Systems, 50kVp, 250mAs). Images were digitized using a Fujifilm Capsula X CR system, from a 35×43cm detector cassette placed on an angulated stand, featuring a 3520×4280 image matrix with an in-plane pixel spacing of 0.1mm. Three images were acquired: two for use with our TDT; and one for comparison, with no detector tilt. Performance was determined by using two line-pair phantoms (Models 07-521 and 07-533, Nuclear Associates) placed orthogonally to each other in the field of view. Custom software corrected for perspective distortion, co-registered and combined the tilted-detector images into a single higher-resolution image. Following unwarping and co-registration, the limiting spatial resolution of an image obtained via the weighted combination of the two orthogonal views (8 lp/mm) is found to be superior to that of a single view acquired with no detector tilt (5 lp/mm). This novel technique shows significant improvement in the spatial resolution of x-ray image acquisitions, using existing x-ray components and detector hardware.

Pollmann, Steven I.; Norley, Chris J. D.; Yuan, Xunhua; Holdsworth, David W.

2012-03-01

113

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

International Nuclear Information System (INIS)

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.)

114

Effect of exposure time reduction towards sensitivity and SNR for computed radiography (CR) application in NDT  

International Nuclear Information System (INIS)

Signal-to-noise ratio (SNR) and sensitivity study of Computed Radiography (CR) system with reduction of exposure time is presented. The purposes of this research are to determine the behavior of SNR toward three different thicknesses (step wedge; 5, 10 and 15 mm) and the ability of CR system to recognize hole type penetrameter when the exposure time decreased up to 80 % according to the exposure chart (D7; ISOVOLT Titan E). It is shown that the SNR is decreased with decreasing of exposure time percentage but the high quality image is achieved until 80 % reduction of exposure time. (author)

115

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

International Nuclear Information System (INIS)

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

116

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

Energy Technology Data Exchange (ETDEWEB)

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

Kerns, James R. [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 and Graduate School of Biomedical Sciences, The University of Texas Health Science Center Houston, Houston, Texas 77030 (United States); Anand, Aman [Department of Radiation Oncology, Mayo Clinic, Scottsdale, Arizona 85259 (United States)

2013-11-15

117

A comparison of low contrast performance for amorphous Silicon/caesium iodide direct radiography with a computed radiography: A contrast detail phantom study  

International Nuclear Information System (INIS)

A range of digital image acquisition devices exists in diagnostic radiology. This study compares contrast performance of two such systems: an amorphous Silicon/caesium iodide (a-Si:CsI) based flat panel (DR) digital chest radiography system and a computed radiography (CR) system. Images of a contrast detail resolution phantom were acquired at a range of radiation doses. Three observers assessed all hardcopy images using a four-alternative forced choice observer perception technique. Contrast detail performance was calculated and low contrast performance quantified. The DR system demonstrated significantly better low contrast performance and potential dose savings of up to 75% compared to the CR system. Threshold levels of contrast detail resolution were defined and levels of under- and over-exposure, compared to the threshold level, were highlighted. Both systems were noise limited at lower exposures and latitude limited at higher exposures. The results demonstrate that the DR system should perform better than the CR system under typical clinical conditions relevant to chest radiography particularly for the detection of low contrast details such as lung metastases or pneumothoraces

118

A comparison of low contrast performance for amorphous Silicon/caesium iodide direct radiography with a computed radiography: A contrast detail phantom study  

Energy Technology Data Exchange (ETDEWEB)

A range of digital image acquisition devices exists in diagnostic radiology. This study compares contrast performance of two such systems: an amorphous Silicon/caesium iodide (a-Si:CsI) based flat panel (DR) digital chest radiography system and a computed radiography (CR) system. Images of a contrast detail resolution phantom were acquired at a range of radiation doses. Three observers assessed all hardcopy images using a four-alternative forced choice observer perception technique. Contrast detail performance was calculated and low contrast performance quantified. The DR system demonstrated significantly better low contrast performance and potential dose savings of up to 75% compared to the CR system. Threshold levels of contrast detail resolution were defined and levels of under- and over-exposure, compared to the threshold level, were highlighted. Both systems were noise limited at lower exposures and latitude limited at higher exposures. The results demonstrate that the DR system should perform better than the CR system under typical clinical conditions relevant to chest radiography particularly for the detection of low contrast details such as lung metastases or pneumothoraces.

McEntee, Mark [Diagnostic Imaging, School of Medicine and Medical Science, UCD Dublin, Belfield, Dublin 4 (Ireland)]. E-mail: mark.mcentee@ucd.ie; Frawley, Helena [Beaumont Hospital, Dublin (Ireland); Brennan, Patrick C. [Diagnostic Imaging, School of Medicine and Medical Science, UCD Dublin, Belfield, Dublin 4 (Ireland)

2007-05-15

119

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

120

Gamma-ray and neutron radiography as part of a pulsed fast neutron analysis inspection system  

International Nuclear Information System (INIS)

A gamma-ray and neutron radiography system has been developed to provide useful supplemental information for a Pulsed Fast Neutron Analysis (PFNA) cargo inspection system. PFNA uses a collimated beam of pulsed neutrons to interrogate cargoes using (n, ?x) reactions. The PFNA source produces both gamma rays as well as neutrons. The transmission of both species through the cargo is measured with an array of plastic scintillators. Since the neutron and gamma-ray signals are easily separated by arrival time a separate image can be made for both species. The radiography measurement is taken simultaneously with the PFNA measurement turning PFNA into an emission and transmission imaging system, thus enhancing the PFNA radiography system

 
 
 
 
121

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

Directory of Open Access Journals (Sweden)

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

122

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

123

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.

124

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

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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.

Rabinowitz, T.G. (Mount Sinai School of Medicine, New York, NY); Efremidis, S.C.; Cohen, B.; Dan, S.; Efremidis, A.; Chahinian, A.P.; Teirstein, A.S.

1982-08-01

125

Evaluating radiographic parameters for mobile chest computed radiography: Phantoms, image quality and effective dose  

International Nuclear Information System (INIS)

Conventional chest radiography is technically difficult because of wide variations in tissue attenuations in the chest and limitations of screen-film systems. Mobile chest radiography, performed bedside on hospital inpatients, presents additional difficulties due to geometric and equipment limitations inherent in mobile x-ray procedures and the severity of illness in the patients. Computed radiography (CR) offers a different approach for mobile chest radiography by utilizing a photostimulable phosphor. Photostimulable phosphors overcome some image quality limitations of mobile chest imaging, particularly because of the inherent latitude. Because they are more efficient in absorbing lower-energy x rays than rare-earth intensifying screens, this study evaluated changes in kVp for improving mobile chest CR. Three commercially available systems were tested, with the goal of implementing the findings clinically. Exposure conditions (kVp and grid use) were assessed with two acrylic-and-aluminum chest phantoms which simulated x-ray attenuation for average-sized and large-sized adult chests. These phantoms contained regions representing the lungs, heart and subdiaphragm to allow proper CR processing. Signal-to-noise ratio (SNR) measurements using different techniques were obtained for acrylic and aluminum disks (1.9 cm diameter) superimposed in the lung and heart regions of the phantoms, where the disk thicknesses (contrast) were determined from disk visibility. Effective dosrmined from disk visibility. Effective doses to the phantoms were also measured for these techniques. The results indicated that using an 8:1, 33 lines/cm antiscatter grid improved the SNR by 60-300 % compared with nongrid images, depending on phantom and region; however, the dose to the phantom also increased by 400-600 %. Lowering x-ray tube potential from 80 to 60 kVp improved the SNR by 30-40 %, with a corresponding increase in phantom dose of 40-50 %. Increasing the potential from 80 to 100 kVp reduced both the SNR and the phantom dose by approximately 10%. The most promising changes in technique for trial in clinical implementation include using an antiscatter grid, especially for large patients, and potentially increasing kVp

126

Radiologic analysis of femoral acetabular impingement: from radiography to MRI  

International Nuclear Information System (INIS)

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.)

127

Radiologic analysis of femoral acetabular impingement: from radiography to MRI  

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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

128

Analysis of physeal growth in dogs, using biplanar radiography  

International Nuclear Information System (INIS)

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

129

Characterizing Parameters Using Expert Judgment and Bayesian Update in the Risk Analysis for Field Radiography  

International Nuclear Information System (INIS)

Radiological risk assessments can be calculated using crisp estimates of the exposure variables (e.g., source term, exposure time, distance, exposure frequency). However, aggregate and cumulative exposure studies require a better understanding of exposure variables and the uncertainty and variability associated with them. Probabilistic risk assessment (PRA) is a tool for quantitative estimation of risk and associated uncertainties. The prevailing method in PRA is Monte Carlo analysis(MCA), which is a means of quantifying uncertainty or variability in a probabilistic framework using computer simulation. Risk is expressed as the sum of the product of the frequency and consequence pair over the possible states. The state of a system is a description of its physical condition and its environment. The status of all the barriers, controls defining the system and its environment determine the state. The radiation exposure is given by the summation of the exposure resulted from relevant exposure pathways. The most important factor of risk assessment is characteristic of the input variable. Risk estimation involves propagating the uncertainty distributions through the PRA models. In this study, the data analysis portion of field radiography PRA is addressed for estimates of the parameters used to determine the frequencies and consequences of the various events modeled. The Delphi survey and the Bayesian update technique are employed in characterizing uncertain variables characterizing uncertain variables

130

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

International Nuclear Information System (INIS)

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

131

Evaluation of an image receptor for computed radiography system in mammography  

International Nuclear Information System (INIS)

In this work, the performance of an image receptor for computed radiography system, Kodak CR850, was assessed through tests, recommended by the European protocol, with a specific image plate for mammography where were analyzed the Contrast-to-noise ratio (CNR) and uniformity and linearity of detector. The CNRs were 14.1, 11.7, 10.3, 8.4, 7.1 and 5.9 for 2, 3, 4, 5, 6 and 7 cm polymethylmethacrylate (PMMA) thickness, respectively. The linearity between detector response and dose, obtained a correlation coefficient (R2) greater than 0.99, and the maximum variation found in the detector uniformity calculation was 3.94 in the lower right corner. (author)

132

Initial quantitative evaluation of computed radiography in an intensive care unit  

International Nuclear Information System (INIS)

The first computed radiography (CR) unit in Australia was installed at St Vincent's Hospital, Melbourne, in February 1994. An initial qualitative evaluation of the attitude of the intensive care unit (ICU) physicians to the CR unit was conducted by use of a survey. The results of the survey of ICU physicians indicated that images were available faster than under the previous system and that the use of the CR system was preferred to evaluate chest tubes and line placements. While it is recognized that a further detailed radiological evaluation of the CR system is required to establish the diagnostic performance of CR compared with conventional film, some comments on the implementation of the system and ICU physician attitudes to the CR system are put forward for consideration by other hospitals examining the possible use of CR systems. 11 refs., 1 tab

133

Conventional radiography and computed tomography in preoperative staging of bronchial carcinoma  

International Nuclear Information System (INIS)

For lung tumor staging both radiographic methods produced similar results for tumor size determination, detection of metastases in the tracheobronchial lymph nodes, and for estimating the distance of the tumor to the carina. Conventional radiography was advantageous in locating the tumor and in demonstrating the involvement of the bronchi and of the bronchopulmonary lymph nodes. Computed tomography was superior for evaluating the involvement of the thoracic wall and the diaphragm, and especially for the invasion of the heart and the big mediastinal blood vessels. Furthermore, metastases of lymph nodes in the paratracheal, ventrocranial and dorsocaudal mediastinum were detected more accurately by CT. With regard to the non-operated patients, CT examination of the upper abdomen should be carried out preoperatively, because 18% of the patients suffered from metastases in the liver, kidneys or adrenal glands, which were not previously suspected clinically. (Auth.)

134

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

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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.)

Szucs-Farkas, Zsolt; Vock, Peter [Inselspital, Berne University Hospital and University of Berne, Department of Diagnostic, Interventional and Paediatric Radiology, Berne (Switzerland)

2009-09-15

135

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

Directory of Open Access Journals (Sweden)

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

Muhogora Wilbroad

2011-01-01

136

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

Science.gov (United States)

The aim of this study was to develop a homemade phantom for quantitative quality control in chest computed radiography (CR). The phantom was constructed from copper, aluminium, and polymenthylmethacrylate (PMMA) plates as well as Styrofoam materials. Depending on combinations, the literature suggests that these materials can simulate the attenuation and scattering characteristics of lung, heart, and mediastinum. The lung, heart, and mediastinum regions were simulated by 10 mm x 10 mm x 0.5 mm, 10 mm x 10 mm x 0.5 mm and 10 mm x 10 mm x 1 mm copper plates, respectively. A test object of 100 mm x 100 mm and 0.2 mm thick copper was positioned to each region for CNR measurements. The phantom was exposed to x-rays generated by different tube potentials that covered settings in clinical use: 110-120 kVp (HVL=4.26-4.66 mm Al) at a source image distance (SID) of 180 cm. An approach similar to the recommended method in digital mammography was applied to determine the CNR values of phantom images produced by a Kodak CR 850A system with post-processing turned off. Subjective contrast-detail studies were also carried out by using images of Leeds TOR CDR test object acquired under similar exposure conditions as during CNR measurements. For clinical kVp conditions relevant to chest radiography, the CNR was highest over 90-100 kVp range. The CNR data correlated with the results of contrast detail observations. The values of clinical tube potentials at which CNR is the highest are regarded to be optimal kVp settings. The simplicity in phantom construction can offer easy implementation of related quality control program. PMID:21430855

Muhogora, Wilbroad; Padovani, Renato; Msaki, Peter

2011-01-01

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 horfication of fine detail information in horse radiology. (author)

138

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)

139

Quantitative Kinetic Analysis of Lung Nodules Using the Temporal Subtraction Technique in Dynamic Chest Radiographies Performed with a Flat Panel Detector  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Early detection and treatment of lung cancer is one of the most effective means of reducing cancer mortality, and to this end, chest X-ray radiography has been widely used as a screening method. A related technique based on the development of computer analysis and a flat panel detector (FPD) has enabled the functional evaluation of respiratory kinetics in the chest and is expected to be introduced into clinical practice in the near future. In this study, we developed a computer analysis algor...

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

2009-01-01

140

Comparison of radiography, computed tomography and magnetic resonance imaging in the detection of sacroiliitis accompanying ankylosing spondylitis  

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Objective. To compare magnetic resonance (MR) imaging, computed tomography (CT), and radiography in the detection of sacroiliitis accompanying ankylosing spondylitis (AS). Design and subjects. Nine volunteers and 24 patients were recruited. Radiography, CT, and MR imaging were completed within a 1-week period in 24 patients with AS. In precontrast MR examination, spin-echo T1, fast spin-echo T2, and gradient echo with rephasing T2* images were obtained without fat saturation using a 0.3-T imager for all volunteers and patients. Postcontrast MR examination was performed using the same precontrast SE T1 sequence for patients with AS. Results and conclusions. MR imaging directly showed the normal cartilage in all 16 sacroiliac joints of the 8 volunteers. In the 24 patients with AS, cartilage abnormalities were observed in 42 sacroiliac joints. More diagnoses of sacroiliitis were made using MR and CT imaging than using radiography (P<0.001). Therefore, low-field-strength MR can be useful in detecting early sacroiliitis in patients with AS. MR imaging was able to reveal early cartilage changes and bone marrow edema, which could not be found by either CT or radiography. (orig.) With 5 figs., 4 tabs., 36 refs.

Yu, Wei; Feng Feng; Yang Hongzen; Jiang Ming [Department of Radiology, Peking Union Medical College Hospital, Beijing (China); Dion, E.; Genant, H.K. [Department of Radiology, Musculoskeletal Section and Osteoporosis and Arthritis Research Group, University of California San Francisco, CA 94143-0628 (United States)

1998-06-01

 
 
 
 
141

Comparison of radiography, computed tomography and magnetic resonance imaging in the detection of sacroiliitis accompanying ankylosing spondylitis  

International Nuclear Information System (INIS)

Objective. To compare magnetic resonance (MR) imaging, computed tomography (CT), and radiography in the detection of sacroiliitis accompanying ankylosing spondylitis (AS). Design and subjects. Nine volunteers and 24 patients were recruited. Radiography, CT, and MR imaging were completed within a 1-week period in 24 patients with AS. In precontrast MR examination, spin-echo T1, fast spin-echo T2, and gradient echo with rephasing T2* images were obtained without fat saturation using a 0.3-T imager for all volunteers and patients. Postcontrast MR examination was performed using the same precontrast SE T1 sequence for patients with AS. Results and conclusions. MR imaging directly showed the normal cartilage in all 16 sacroiliac joints of the 8 volunteers. In the 24 patients with AS, cartilage abnormalities were observed in 42 sacroiliac joints. More diagnoses of sacroiliitis were made using MR and CT imaging than using radiography (P<0.001). Therefore, low-field-strength MR can be useful in detecting early sacroiliitis in patients with AS. MR imaging was able to reveal early cartilage changes and bone marrow edema, which could not be found by either CT or radiography. (orig.)

142

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2014-05-15

143

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

144

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)

145

Implementación de un sistema de radiografía computarizada para verificación de tratamientos de radioterapia de intensidad modulada / Implementation of a computed radiography system for intensity modulated radiotherapy treatments verification  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Giraldo Palacio, John Freddy (2010) Implementación de un sistema de radiografía computarizada para verificación de tratamientos de radioterapia de intensidad modulada / Implementation of a computed radiography system for intensity modulated radiotherapy treatments verification. Maestría thesis, Universidad Nacional de Colombia.

Giraldo Palacio, John Freddy

2010-01-01

146

Comparison of three different schemes for dual-energy subtraction imaging in digital radiography: a signal-to-noise analysis  

Science.gov (United States)

Dual-energy subtraction imaging techniques allow the tissue and bone structures in the patient to be imaged separately, thus removing some obscurity resulted from the overlapping of the two structures. Furthermore, they provide the potential for the tissue or bone contents to be quantified for diagnostic use. Thus, capabilities for dual-energy subtraction imaging are often incorporated with new digital radiography techniques. There are three different schemes for implementing dual-energy subtraction imaging techniques. Among them, dual-kVp and sandwich detector approaches are two most often used schemes. A third scheme is the single kVp-dual filter approach which allows a more flexible control of the spectra while avoiding kVp switching. It is suitable for digital radiography techniques using two linear detector arrays. In this paper, the signal-to-noise properties of these three schemes is computed for various combinations of kVp, filters and patient thicknesses (tissue and bone). Based on the signal-to-noise analysis, they are compared to each other for the efficiency of x ray usage, dose efficiency, and accuracy for background subtraction and thickness measurement.

Shaw, Chris C.; Gur, David

1992-06-01

147

Amorphous selenium flat-panel detector digital radiography versus computed radiography: phantom study of depiction of simulated lesion and dose reduction  

International Nuclear Information System (INIS)

Objective: To compare an amorphous selenium fiat-panel detector digital radiography (DR) with a computed radiography(CR) for the depiction of simulated pulmonary lesion, as well as for evaluation of dose reduction. Methods: Simulated linear, reticular, and nodular lesion were located in an anthropomorphic chest phantom. The phantom was exposed by DR and CR with different mAs sets. The entrance surface doses were recorded for all images. Hard copy images were generated at different dose levels. Images were presented in a random order to four independent radiologists. They subjectively rated the visibility of simulated pulmonary lesion. Statistical significance of difference was analysed with wilcoxon test. Results: The visibility of simulated linear and reticular lesions on the images obtained with DR was superior to the images from CR at 2.0 and 3.2 mAs, P 0.05). DR was superior to CR in detection small nodular(diameter < 10 mm) lesions at different dose level(mAs: 2.0, 3.2, 5.0, 6.3), P<0.05 (Z=-2.237, P=0.018; Z=-2.384, P=0.017; Z=-2.388, P=0.017; Z=-2.366, P=0.018). When the visibility of simulated pulmonary lesion for DR and CR were equal, The radiation dose was reduce approximately 65% with the DR. Conclusions: DR was superior to CRthe DR. Conclusions: DR was superior to CR in depiction of tiny lesion and dose reduction greatly. (authors)

148

Post-operative observation of ilio-apophyseal transplants on the basis of radiography, computed tomography, autoradiography and histological assessment  

International Nuclear Information System (INIS)

A study in 25 rabbits, in which the acetabular roof was reinforced by inserting a wedge-shaped autologous tissue fragment of the apophysis, led to the following conclusions: That complete healing and ossification of the implant took place within the observation period; that radiography, computed tomography, autoradiography and histology consistently provided evidence in confirmation of ossification; that a wedge-shaped fragment of apophyseal cartilage is a suitable material for plastic surgery in the acetabular roof. (TRV)

149

Initial experience with soft-copy display of computed radiography images on three picture archive and communication systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We recently installed picture archive and communication systems (PACS) from three different vendors on our campus for evaluation. A major part of this evaluation involved assessing the capabilities of these systems for displaying computed radiography (CR) images for primary interpretation. The three PACS provided different functionality for CR image display in terms of availability of the proprietary Fuji CR image processing algorithms, availability of user-specified contrast look-up tables, ...

Hangiandreou, Nicholas J.; Cesar, Laurie J.; Bruesewitz, Michael R.; Hartman, Thomas E.; King, Bernard F.; Rose, John F.; Swee, Ronald G.; Wenger, Doris E.; James, E. Meredith; Gray, Joel E.

1997-01-01

150

Clinical analysis of 125I seed implants in worst-casts of the malignant tumors after radiography and chemotherapy  

International Nuclear Information System (INIS)

Objective: To investigate the curative effect and side reaction after 125I seed implanted among tissue were treated the malignant neoplasm by radiography and chemotherapy. Methods: Retrospective analysis the cancerous sufferer after the failure of radiography and chemotherapy, percutaneous puncture or intraoperative under gaze forward 125I seed were implanted the bed of the tumour forever. Follow-up blood routine examination, symptom, sign, using USG or CT observe the change of the tumour and the distribution of the particles etc. Results: In 3 cases, treat 2 cases, tumour reduced obviously, symptoms improved obviously, the face of the ulcer cured, the particles did not shift, hemogram did not decline obviously. Conclusion: 125I seed among the tissue implanted forever for the unsuccessful case after radiography and chemotherapy supply a new therapeutic methods. In the neat future curative effect is exactly, toxic reaction is small, which can remedy the deficiency of the treatment for radiography and chemotherapy. (authors)

151

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

152

Correlation of image quality with exposure index and processing protocol in a computed radiography system  

International Nuclear Information System (INIS)

The correlation of image quality with the exposure index (EI) and the processing protocol was investigated in a Kodak computed radiography (CR) system using clinical radiographs and a water phantom containing an aluminium and a copper step-wedge. The phantom was exposed to different dose levels and the acquired images were processed using four clinical protocols. The quality of these images was evaluated in terms of image brightness, contrast and noise. In clinical radiographs, there was no straightforward correlation of image quality with EI. In phantom images, higher EI values improved contrast and reduced noise but after a point this improvement does not justify the implied increase in patient dose. Image brightness, contrast and noise were also strongly dependent on the processing protocol. To obtain the images of satisfactory quality with the Kodak CR system, a dose slightly higher than those used in 400 relative speed screen-film systems and a processing protocol designated for the specific radiographic examination are required. (authors)

153

Correlation of image quality with exposure index and processing protocol in a computed radiography system.  

Science.gov (United States)

The correlation of image quality with the exposure index (EI) and the processing protocol was investigated in a Kodak computed radiography (CR) system using clinical radiographs and a water phantom containing an aluminium and a copper step-wedge. The phantom was exposed to different dose levels and the acquired images were processed using four clinical protocols. The quality of these images was evaluated in terms of image brightness, contrast and noise. In clinical radiographs, there was no straightforward correlation of image quality with EI. In phantom images, higher EI values improved contrast and reduced noise but after a point this improvement does not justify the implied increase in patient dose. Image brightness, contrast and noise were also strongly dependent on the processing protocol. To obtain the images of satisfactory quality with the Kodak CR system, a dose slightly higher than those used in 400 relative speed screen-film systems and a processing protocol designated for the specific radiographic examination are required. PMID:18245792

Tsalafoutas, I A; Blastaris, G A; Moutsatsos, A S; Chios, P S; Efstathopoulos, E P

2008-01-01

154

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

155

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

156

Studies on the correlation between photograph condition and image quality on computed radiography  

International Nuclear Information System (INIS)

Objective: To evaluate how to use reasonably the combination of exposure dose and speed class on the base of imaging quality on computed radiography (CB). Methods: Based on threshold contrast- detail detectability (TCCD)technique, phantom TO. 16 photography was done with 55, 65 and 75 kV, and combination with three kinds of different exposure dose and speed class respectively. Three radiologists scored each image sequence using double blind method and calculated the threshold detection index (HT). The imaging quality of knee joint, chest and lumbarspine was also evaluated by these radiologists on the base of diagnostic quality and the different combination of exposure close and speed class. Results: Exposure dose was increased by using lower kV value, and Hr value was increased by lower exposure grade rather than higher kV value. Exposure dose was decreased obviously and speed class was increased in the good contrast location at the same kV value. Conclusions: Based on the demand of diagnostic quality and the contrast of the checked location, the speed class should be carefully selected to decrease the radiation dose exposure to patients, without any decrease of the diagnostic quality. (authors)

157

Soft-tissue radiography, computed tomography, and ultrasonography of partial Achilles tendon ruptures  

International Nuclear Information System (INIS)

Ultrasonography (US) was compared with soft-tissue radiography (STR) and computed tomography (CT) for demonstration of partial Achilles tendon ruptures. Thirty-nine patients suffering from chronic localized painful Achilles tendon swelling were examined. The patients had all undergone a previous clinical examination, resulting in a suspicion of a non-healed partial tear in 62 out of the 78 tendons. STR showed unspecific tendon pathology such as thickening and diffuse tendon margins. CT resulted in a better delineation of intra- as well as extratendinous abnormalities compared to STR. Various pathologic changes were seen on CT in 54 tendons and in 29 of these, localized intratendinous hypodensities indicated partial ruptures. At US, abnormal changes were observed in 69 tendons, of which 54 had discontinuity of tendon fibers, focal hypoechoic areas, and localized swelling indicating partial ruptures. In 9 cases with surgically proven partial ruptures, US was correct in all cases, while CT was false-negative in 3. STR only showed localized swelling. It was concluded that US was a better method than STR and CT for the detection of partial ruptures and the US findings correlated well with the surgical findings. (orig.)

158

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

Energy Technology Data Exchange (ETDEWEB)

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

Dom, Sulaiman M. [Medical Imaging Program, Faculty of Health Sciences, Universiti Teknologi MARA, 46000 Petaling Jaya (Malaysia)], E-mail: smd_dom@hotmail.com; Yusoff, Nadzri M.; Amin, Zulkifli M. [Medical Imaging Program, Faculty of Health Sciences, Universiti Teknologi MARA, 46000 Petaling Jaya (Malaysia)

2010-05-15

159

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)

160

Detection of electron beam energy variations using a computed radiography system.  

Science.gov (United States)

A method to evaluate the electron beam energy constancy by employing the computed radiography (CR) system has been developed. In this method, a right triangular plastic wedge is used to produce a curve of the CR storage phosphor plate signal versus the wedge thickness. The curve, which resembles the percentage depth ionization curve of the clinical electron beams, can be used to derive the energy constancy metric EC(50). The sensitivity of the method was tested using polystyrene sheets of variable thicknesses. For electron energies up to 12 MeV, energy changes induced by 1.5 mm thick polystyrene can be detected, while a 2.3 mm thick polystyrene sheet is required for higher energies. The measurements were carried out over a two-year period. The results showed a good reproducibility with the use of the same CR plate and cassette, and without the requirement of calibration procedures. The two-year range of the EC(50) was within the 99% confidence intervals, and the standard deviation of the EC(50) was measured to be from 0.3 to 0.4 mm for different beam energies. This technique provides an efficient and accurate method to perform the electron beam energy check and could be used by centers equipped with the CR system without requiring additional detection devices. PMID:19918220

Cai, Yang C; Ge, Yuanyuan; Bernard, Damian; Turian, Julius; Chu, James C H

2009-01-01

 
 
 
 
161

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.)

162

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

163

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

164

PyRAT (python radiography analysis tool): overview  

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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

165

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2011-11-15

166

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.

167

Neutron Radiography  

Directory of Open Access Journals (Sweden)

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

A. R. Reddy

2014-03-01

168

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

International Nuclear Information System (INIS)

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

169

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

170

neutron radiography  

International Nuclear Information System (INIS)

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

171

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

DEFF Research Database (Denmark)

BACKGROUND: The objectives of the present study were, with multidetector computed tomography (CT) as the reference method, to determine the performance of magnetic resonance imaging (MRI) and radiography for the detection of bone erosions in rheumatoid arthritis wrist bones, and to test whether measuring volumes of erosions on CT and MRI is reproducible and correlated to semiquantitative assessments (scores) of erosions on CT, MRI and radiography. METHODS: Seventeen patients with rheumatoid arthritis and four healthy control individuals underwent CT, MRI and radiography of one wrist, performed on the same day. CT was performed on a Philips Mx8000IDT unit (voxel size 0.4 mm x 0.4 mm x 1 mm) and MRI was performed on a Philips Panorama 0.6T unit (voxel size 0.4 mm x 0.4 mm x 0.4 mm). Images were evaluated separately for erosions in all wrist bones and were scored according to the principles of the Outcome Measures in Rheumatology Rheumatoid Arthritis MRI Scoring System (CT and MRI) and the Sharp/van der Heijde (radiographs) scoring methods. Measurements of erosion volumes of all erosions were performed twice with a 1-week interval. RESULTS: With CT as the reference method, the overall sensitivity, specificity and accuracy (concordance) of MRI for detecting erosions were 61%, 93% and 77%, respectively, while the respective values were 24%, 99% and 63% for radiography. The intramodality agreements when measuring erosion volumes were high for both CT and MRI (Spearman correlation coefficients 0.92 and 0.90 (both P < 0.01), respectively). Correlations between volumes and scores of individual erosions were 0.96 for CT and 0.99 for MRI, while they were 0.83 (CT) and 0.80 (MRI) for persons' total erosion volume and total score (all P < 0.01). CONCLUSION: With CT as the reference method, MRI showed moderate sensitivity and good specificity and accuracy for detection of erosions in rheumatoid arthritis and healthy wrist bones, while radiography showed very low sensitivity. The tested volumetric method was highly reproducible and correlated to scores of erosions.

DØhn, Uffe MØller; Ejbjerg, Bo J

2008-01-01

172

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

Energy Technology Data Exchange (ETDEWEB)

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

Dewanckele, J., E-mail: jan.dewanckele@gmail.com [Department of Geology and Soil Science—UGCT, Ghent University, Krijgslaan 281 S8, B-9000 Ghent (Belgium); De Kock, T. [Department of Geology and Soil Science—UGCT, Ghent University, Krijgslaan 281 S8, B-9000 Ghent (Belgium); Fronteau, G. [University of Reims Champagne-Ardenne (URCA), GEGENAA, EA3795 Reims (France); Derluyn, H. [Chair of Building Physics, ETH Zurich, HIL E 47.2, Wolfgang-Pauli-Strasse 15, 8093 Zürich Hönggerberg (Switzerland); Vontobel, P. [Spallation Neutron Source Division, Paul Scherrer Institut (PSI), Villigen (Switzerland); Dierick, M.; Van Hoorebeke, L. [Department of Physics and Astronomy—UGCT, Ghent University, Proeftuinstraat 86, B-9000 Ghent (Belgium); Jacobs, P.; Cnudde, V. [Department of Geology and Soil Science—UGCT, Ghent University, Krijgslaan 281 S8, B-9000 Ghent (Belgium)

2014-02-15

173

The stationary neutron radiography system  

International Nuclear Information System (INIS)

In order to prevent corrosion-related aircraft loss, one must detect corrosion in the component before failure. This can be accomplished through the nondestructive Inspection (NDI) technique called neutron radiography. Implementation of neutron radiography for NDI is taking place at McClellan AFB, headquarters for the Sacramento Air Logistics Center (SMALC). Three systems will utilize the neutron radiography technique: the Transportable Neutron Radiography System (TNRS), the Maneuverable Neutron Radiography System (MNRS), and the Stationary Neutron Radiography System (SNRS). The SNRS is a specially designed facility, consisting of: TRIGA Reactor; Shield and Containment; four radiography bays; two robotic parts positioning systems; two real-time imaging systems. Like other TRIGA systems, the SNRS can also inspect advanced composite materials, turbine blades, hydraulic components, pyrotechnics. Further capabilities include neutron activation analysis using a pneumatic tube transfer system and nuclear hardening studies. The SNRS will also be capable of pulsing

174

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

Science.gov (United States)

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

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

2014-12-01

175

Computed image analysis of neutron radiographs  

International Nuclear Information System (INIS)

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

176

A comparison between digital radiography, computed tomography, and magnetic resonance in the detection of gunshot residues in burnt tissues and bone.  

Science.gov (United States)

The radiological search for GSR is crucial in burnt material although it has been rarely tested. In this study, thirty-one bovine ribs were shot at near-contact range and burnt to calcination in an oven simulating a real combustion. Computed tomography (CT) and magnetic resonance (MR) were performed before and after carbonization and compared with former analyses with DR (digital radiography); thus comparing the assistance, the radiological methods can provide in the search for GSR in fresh and burnt bone. DR demonstrated the greatest ability in the detection of metallic residues, CT showed lower abilities, while MR showed a high sensitivity only in soft tissues. Thus, DR can be considered as the most sensitive method in the detection of GSR in charred bones, whereas CT and MR demonstrated much less reliability. Nonetheless, the MR ameliorates the analysis of gunshot wounds in other types of remains with large quantities of soft tissues. PMID:24147424

Amadasi, Alberto; Borgonovo, Simone; Brandone, Alberto; Di Giancamillo, Mauro; Cattaneo, Cristina

2014-05-01

177

Filmless Radiography  

Science.gov (United States)

Technology initially prototyped under a Small Business Innovation Research contract between Quantex Corporation and Langley Research Center was licensed to Liberty Technology and incorporated into RADView, a new filmless radiography technology. The NASA-sponsored work involved the investigation of Electron Trapping, which led to a solid-state film that uses a special class of photoluminescent materials to capture radiographic images. RadView is a total imaging solution for the conversion of radiographic film records to digital format and digital acquisitions of radiographs. With the RADView technology, there is a reduction of exposure times and errors; film waste is eliminated; and the efficiency of data management and precise image analysis is boosted. The solid-state film can be exposed, read, erased, and re- exposed indefinitely until mechanical replacement is required. Digital images can be stored to optical media for up to 100 years and beyond without information loss.

1997-01-01

178

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

International Nuclear Information System (INIS)

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

179

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-12-15

180

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

 
 
 
 
181

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

Energy Technology Data Exchange (ETDEWEB)

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

Boyd D. Christensen

2009-05-01

182

High-resolution computed tomography versus chest radiography in the diagnosis of interstitial lung disease in systemic sclerosis  

International Nuclear Information System (INIS)

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)

183

Organ-specific dosimetry in spinal radiography: an analysis of genetic and somatic effects  

Energy Technology Data Exchange (ETDEWEB)

Radiation doses absorbed by the uterus, ovary, testicle and active bone marrow are computed for cervical, thoracic, lumbar, full spine and chest series performed under typical office conditions. Assuming a nonthreshold, linear relationship between dose and radiogenic effect, the computed tissue-specific doses are used to estimate the probability that each X-ray series might enhance the statistical probability of occurrence of an adult leukemia fatality of the irradiated patient; a childhood leukemia, mental retardation or cancer fatality as a result of fetal irradiation; or a variety of sex cell chromosomal aberrations in irradiated patients. It is concluded that the greatest hazard to active bone marrow, the uterus and the gonads is posed by lumbar and full spine radiography and that the need to adequately justify such exposure is mandatory; furthermore, in these series, irradiation of the ovary is 10 times as great as that of the testicle. Lumbar radiographic examinations can be made significantly safer by the elimination of the lumbosacral spot view.

Fickel, T.E.

1988-02-01

184

Organ-specific dosimetry in spinal radiography: an analysis of genetic and somatic effects  

International Nuclear Information System (INIS)

Radiation doses absorbed by the uterus, ovary, testicle and active bone marrow are computed for cervical, thoracic, lumbar, full spine and chest series performed under typical office conditions. Assuming a nonthreshold, linear relationship between dose and radiogenic effect, the computed tissue-specific doses are used to estimate the probability that each X-ray series might enhance the statistical probability of occurrence of an adult leukemia fatality of the irradiated patient; a childhood leukemia, mental retardation or cancer fatality as a result of fetal irradiation; or a variety of sex cell chromosomal aberrations in irradiated patients. It is concluded that the greatest hazard to active bone marrow, the uterus and the gonads is posed by lumbar and full spine radiography and that the need to adequately justify such exposure is mandatory; furthermore, in these series, irradiation of the ovary is 10 times as great as that of the testicle. Lumbar radiographic examinations can be made significantly safer by the elimination of the lumbosacral spot view

185

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

Directory of Open Access Journals (Sweden)

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

Tadas Venskutonis

2014-07-01

186

Measurement of focal spot size with slit camera using computed radiography and flat-panel based digital detectors  

International Nuclear Information System (INIS)

The purpose of this study was to evaluate the use of digital x-ray imaging detectors for the measurement of diagnostic x-ray tube focal spot size using a slit camera. Slit camera images of two focal spots for a radiographic x-ray tube were acquired with direct-exposure film (DF) (as specified by the National Electrical Manufacturers Association [NEMA] Standards Publication No. XR 5, 1992), computed radiography (CR) imaging plates, and an a-Si:H/CsI:Tl-based flat-panel (FP) detector. Images obtained with the CR and the FP were acquired over a broad range of detector entrance exposure levels. The DF slit images were evaluated according to NEMA specifications (visually, using a 7x magnifying glass with reticule) by six medical physicists. Additionally, the DF images were digitized and the focal spot sizes obtained from the digital profiles of the slit. The CR and the FP images were analyzed in a manner similar to the digitized DF images. It took less than 20 minutes for a complete CR or FP measurement of focal spot size in two dimensions. In comparison, a typical DF measurement with visual evaluation takes at least 60 minutes, in our experience. In addition to a great reduction in measurement time achieved by using digital detectors, the tube loading requirements were reduced to ?20 mAs compared with ?1000 mAs when using the DF technique. The calculated focal spot sizes for CR and FP differed from those of digitized DF by -2.4% to +4.8% (?=2.5%), far less than the -o +4.8% (?=2.5%), far less than the -16.6% to +9.3% (?=8.1%) variability introduced by the visual evaluation of the slit image. In addition, the calculated focal spot sizes for the CR and the FP images maintained a coefficient of variation <1.0% over the broad range of exposure levels. Based upon these results, we conclude that (1) FP and CR detectors yield consistent results in measurements of x-ray tube focal spot sizes, (2) compared to DF, CR and FP significantly reduce measurement time and tube loading requirements, (3) CR and FP readily permit digital profile analysis, thereby eliminating observer error, and (4) unlike DF, CR and FP are independent of exposure level

187

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

International Nuclear Information System (INIS)

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

188

Voludensitometry: optimization of the computation of the 3D Radon Transform from the cone-beam X-ray radiographies  

International Nuclear Information System (INIS)

The aim of the voludensitometry is to reconstruct the material density function all among a three-dimensional area of interest from a set of digital radiographies acquired all around the object or the patient. We study the case where the X-ray source describes a circular trajectory centred on the object. The cone-beam geometry of the rays prevents to decompose the inverse problem in a superposition of two-dimensional reconstructions. We use the 3D Radon Transform and its inversion formula to implement a direct reconstruction algorithm. We describe here a powerful method to compute an approximation of the 3D Radon Transform. We state in particular, how it is possible to use the reprojection algorithm defined by P.M. Joseph

189

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 increa 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)

190

Changes of the hip joints associated with chronic subluxation and dislocation: CT and plain radiography analysis  

Energy Technology Data Exchange (ETDEWEB)

Secondary osteoarthritis of the hip joint is a common disease and is frequently followed by chronic subluxation and dislocation. Twenty four cases of the secondary osteoarthritis associated with chronic subluxation and dislocation of the hip joints were evaluated with plain radiography and computed tomography. We retrospectively analyzed 1) the osteoarthritis and calcification of the acetabular labrum, 2) the thickness of the quadrilateral plate of the ilium, and 3) anteroposterior diameter of the acetabulum. The changes of the hip joints in subluxation (n=14) revealed ossification of the acetabular labrum in 12 cases (86%), thickening of the quadrilateral plate of the ilium in 11 cases (78%) but anteroposterior diameter of the acetabulum was not changed. The changes of the hip joints in dislocation (n=10) revealed no evidence of the ossification of the acetabular labrum, thickening of the quadrilateral plate of the ilium in 10 cases (100%) and decreased anteroposterior diameter of the acetabulum. We conclude that CT findings of subluxation and dislocation of the hip joints can be helpful in the evaluation of the secondary osteoarthritis of the hip joints.

Yang, Ik; Ryu, Kyung Nam; Lee, Sun Wha; Choi, Woo Suk; Lee, Eil Seong [Kyung Hee University Hospital, Seoul (Korea, Republic of)

1993-05-15

191

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)

192

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

193

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

Science.gov (United States)

Purpose The aim of this in vitro study was to determine the sensitivity and specificity of cone-beam computed tomography (CBCT) and digital periapical radiography in the detection of mesial root perforations of mandibular molars. Materials and Methods In this in vitro study, 48 mandibular molars were divided into 4 groups. First, the mesial canals of all the 48 teeth were endodontically prepared. In 2 groups (24 teeth each), the roots were axially perforated in the mesiolingual canal 1-3 mm below the furcation region, penetrating the root surface ("root perforation"). Then, in one of these 2 groups, the mesial canals were filled with gutta-percha and AH26 sealer. Mesial canals in one of the other 2 groups without perforation (control groups) were filled with the same materials. The CBCT and periapical radiographs with 3 different angulations were evaluated by 2 oral and maxillofacial radiologists. The specificity and sensitivity of the two methods were calculated, and P<0.05 was considered significant. Results The sensitivity and specificity of CBCT scans in the detection of obturated root canal perforations were 79% and 96%, respectively, and in the case of three-angled periapical radiographs, they were 92% and 100%, respectively. In non-obturated root canals, the sensitivity and specificity of CBCT scans in perforation detection were 92% and 100%, respectively, and for three-angled periapical radiographs, they were 50% and 96%, respectively. Conclusion For perforation detection in filled-root canals, periapical radiography with three different horizontal angulations would be trustworthy, but it is recommended that CBCT be used for perforation detection before obturating root canals. PMID:24944960

Haghanifar, Sina; Moudi, Ehsan; Mesgarani, Abbas; Bijani, Ali

2014-01-01

194

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

195

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

196

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

International Nuclear Information System (INIS)

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

197

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)

198

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

International Nuclear Information System (INIS)

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

199

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

200

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

International Nuclear Information System (INIS)

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

 
 
 
 
201

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

202

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

203

Industrial radiography  

International Nuclear Information System (INIS)

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

204

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.

205

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

Energy Technology Data Exchange (ETDEWEB)

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.

Jun, Yun Hoa; Cho, Bong Hae [Department of Oral and Maxillofacial Radiology, College of Dentistry, Pusan National University, Pusan (Korea, Republic of)

2009-06-15

206

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

207

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

208

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)

209

Impact of digital radiography on clinical workflow  

Digital Repository Infrastructure Vision for European Research (DRIVER)

It is commonly accepted that digital radiography (DR) improves workflow and patient throughput compared with traditional film radiography or computed radiography (CR). DR eliminates the film development step and the time to acquire the image from a CR reader. In addition, the wide dynamic range of DR is such that the technologist can perform the quality-control (QC) step directly at the modality in a few seconds, rather than having to transport the newly acquired image to a centralized QC sta...

May, Gerald A.; Deer, David D.; Dackiewicz, Doreen

2000-01-01

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

Scatter and beam-hardening corrections in single-exposure dual-energy computed radiography  

International Nuclear Information System (INIS)

A computed radiographic system with a photostimulable phosphor detector has been adapted to acquire single-exposure dual-energy images. The purpose of this work is to optimize the scatter and beam-hardening corrections used to create the tissue-selective and bone-selective images. Scatter and beam-hardening corrections improve the respective material cancellation in these images and are necessary, especially in dense regions, to quantitate lung nodule calcium content

212

Sensitivity of chest radiography, computed tomography, and gallium scanning to metastasis of lung carcinoma  

International Nuclear Information System (INIS)

To determine the efficacy of radiologic techniques in preoperative staging of the mediastinum for lung carcinoma, the authors studied 45 patients with chest films supplemented with oblique views, esophagrams, gallium scans, and computed tomograms (CT). They interpreted the studies and correlated surgical findings using a modified classification of lymph node regions. The mediastinum was positive on chest films in 14 of the 21 cases with pathologically proved mediastinal metastases (33% false-negative). Gallium scans in cases with a positive primary were positive in 12 of 15 cases with mediastinal or hilar metastases (20% false-negative). Computed tomography showed nodes over 1 or 1.5 cm in size in or adjacent to the biopsy-positive node region in 18 of 19 patients (5% false-negative), extranodal mediastinal involvement, and 9 of 10 proven hilar metastases. Computed tomography is a sensitive screening technique in patients who would otherwise require an invasive staging procedure, but is not highly specific (false-positive rate 38%)

213

Transition from screen-film to computed radiography in a paediatric hospital: The missing link towards optimisation  

International Nuclear Information System (INIS)

In paediatrics, the risks associated with ionising radiation should be a major concern, due to children's higher susceptibility to radiation effects. Measure entrance skin dose (ESD) in chest and pelvis X-ray projections and compare the results with the 'European guidelines on quality criteria for diagnostic radiographer images in paediatrics' in order to optimise radiological practice. ESD values were obtained using an ionisation chamber Diamentor M4 KDK (PTW) in 429 children, who underwent chest X-ray or pelvis X-ray in a Computed Radiography system. In the first phase of the study, data were collected according to protocols used in the department; in a second phase different tube voltage values were used according to patient weight. A third phase was carried out, only for chest X-ray, using the exposure parameters of phase 2, plus activating lateral ionisation chamber. Three paediatric radiologists blindly assessed image quality of chest X-ray, using a validated assessment available in the 'European guidelines on quality criteria for diagnostic radiographer images in paediatrics'. Considering all the patients submitted to chest X-ray, the average ESD was 0.22, 0.16 and 0.08 mGy, for phases 1, 2 and 3, respectively. For pelvis X-ray, the average ESD decreased from 1.18 mGy in phase 1 to 0.78 mGy in phase 2. Dose optimisation was achieved. ESD was reduced 63.6 and 33.9 % in chest and pelvis X-ray, respectively. (authors)

214

Linearity and uniformity response as an indicator of performance for Agfa ADC-MD10 computed radiography plates  

International Nuclear Information System (INIS)

Computed radiography (CR) plates are currently used in radiation therapy clinics to acquire digital radiographic images for the purpose of verifying the treatment field size, shape, and location. Each CR plate may be used numerous times, and the use of these digital images allows for easy storage and retrieval of patient data. Over prolonged repeat exposures of the CR plates, however, the image quality begins to degrade, making it increasingly more difficult for the therapists and physicians to determine where one anatomical structure begins, and the other ends. The purpose of this project was to analyze and compare the linearity and uniformity responses of new CR plates, versus CR plates that have been used clinically for a period of 2 years, and determine whether linearity or uniformity response may be used as an indicator of image quality degradation. To determine this, 44 old Agfa MD10 CR plates and 56 new Agfa MD10 CR plates were tested. When comparing the results of the uniformity test, we found both the old and the new plates varied from approximately 0.5% to 3.2%. When comparing the results of the linearity test, we found that the correlation coefficient, R2, for both the old and the new plates varied from approximately 0.996 to 0.998, with the mean values being 0.9972 and 0.9979, respectively. We concluded that linearity and uniformity response cannot be used as an effective method for the evaluation of CR plate performance. Additional research is plate performance. Additional research is currently underway to evaluate various other methods of assessing CR plate performance

215

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-04-01

216

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

217

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

Directory of Open Access Journals (Sweden)

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

S.R. Torelli

2004-04-01

218

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

International Nuclear Information System (INIS)

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 threralateral knees. We conclude that the three methods detected osteoarthritis lesions in rabbit knees, but MRI was less sensitive than XR and CT in detecting lesions compatible with initial osteoarthritis. Since none of the techniques revealed all the lesions, it is important to use all methods to establish an accurate diagnosis. (author)

219

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

Science.gov (United States)

Four standard radiation qualities (from RQA 3 to RQA 9) were used to compare the imaging performance of a computed radiography (CR) system (general purpose and high resolution phosphor plates of a Kodak CR 9000 system), a selenium-based direct flat panel detector (Kodak Direct View DR 9000), and a conventional screen-film system (Kodak T-MAT L/RA film with a 3M Trimax Regular screen of speed 400) in conventional radiography. Reference exposure levels were chosen according to the manufacturer's recommendations to be representative of clinical practice (exposure index of 1700 for digital systems and a film optical density of 1.4). With the exception of the RQA 3 beam quality, the exposure levels needed to produce a mean digital signal of 1700 were higher than those needed to obtain a mean film optical density of 1.4. In spite of intense developments in the field of digital detectors, screen-film systems are still very efficient detectors for most of the beam qualities used in radiology. An important outcome of this study is the behavior of the detective quantum efficiency of the digital radiography (DR) system as a function of beam energy. The practice of users to increase beam energy when switching from a screen-film system to a CR system, in order to improve the compromise between patient dose and image quality, might not be appropriate when switching from screen-film to selenium-based DR systems. PMID:15789578

Monnin, P; Gutierrez, D; Bulling, S; Lepori, D; Valley, J F; Verdun, F R

2005-02-01

220

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

International Nuclear Information System (INIS)

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.)

 
 
 
 
221

Digital Radiography  

Science.gov (United States)

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

1986-01-01

222

Digital radiography  

International Nuclear Information System (INIS)

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

223

Mass radiography  

International Nuclear Information System (INIS)

The relation of expense to benefit of mass radiography (RRU) can no longer be referred to the tuberculosis discovery rate. Far more frequently other thoracic diseases are detected, e.g. tumors, cardiovascular diseases, pneumoconiosis, sarcoidoses, etc. The prerequisite and therefore the immediate objective is the limitation to the defined and detectable group of risks so as to increase the detection rate. In combination with other prophylactic investigations the benefit of RRU can still be increased - it provides a valuable insight into the epidemiology of different social diseases. (orig.)

224

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

225

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

226

MTF analysis of the near-real time neutron radiography facility at MURR  

International Nuclear Information System (INIS)

Several neutron radiography systems designed to view transient processes on a real-time basis have been developed. With the advent of these different real-time systems comes the necessity to develop a means to quantitatively evaluate and compare these systems. A suitable method for measuring the resolution capabilities of the image-forming system is the determination of the modulation transfer function (MTF). The MTF is a measure of an imaging system's ability to reproduce the spatial frequencies present in an image. The system in use at the University of Missouri Research Reactor is described. (Auth.)

227

Digital radiography. A comparison with modern conventional imaging  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The development of computed radiography over the past two decades has transformed radiological imaging. The radiology departments in the 21st century will look very different from those in the preceding period. In this review, the development of digital radiography is presented with a description of its various forms and a comparison with screen film radiography.

Bansal, G. J.

2006-01-01

228

Application of neutron radiography and tomography for analysis of root morphology of growing ginseng  

Energy Technology Data Exchange (ETDEWEB)

The shape of main root of ginseng is very important for its commercial value. The morphology of main root is predominantly determined by the root-growing pattern in one year after transplantation of ginseng seedling(one years root). There are many factors affecting the root growing of young ginseng but no systematic approach has been applied to find the effects of various factors. The main reason for this was no method was sought to see the root shapes non-destructively. Neutron radiography is thought to be an appropriate NDT method for root morphology examination in ginseng and a study on using NR for the research on ginseng is being conducted. Considering that the live plants should be moved to the reactor site for their examination of four or five times per year at least, the pot growing method is indispensable. The pot should contain enough soils for growing-up of ginseng and its maximum size is limited to have good contrast in neutron radiography image of ginseng root. Thus, a preliminary radiographic study was performed to find the proper size of ginseng pot using the NR facility of HANARO. Several pots will be prepared for young ginsengs and they will be examined for about one year.

Kim, Hyun Ho; Sung, Bong Jae; Park, Jong Yoon [Geumsan Agricultural Development and Technology Center, Geumsan (Korea, Republic of); Sim, Cheul Muu; Kim, Young Jin; Lee, Seung Wook [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

2005-07-01

229

Application of neutron radiography and tomography for analysis of root morphology of growing ginseng  

International Nuclear Information System (INIS)

The shape of main root of ginseng is very important for its commercial value. The morphology of main root is predominantly determined by the root-growing pattern in one year after transplantation of ginseng seedling(one years root). There are many factors affecting the root growing of young ginseng but no systematic approach has been applied to find the effects of various factors. The main reason for this was no method was sought to see the root shapes non-destructively. Neutron radiography is thought to be an appropriate NDT method for root morphology examination in ginseng and a study on using NR for the research on ginseng is being conducted. Considering that the live plants should be moved to the reactor site for their examination of four or five times per year at least, the pot growing method is indispensable. The pot should contain enough soils for growing-up of ginseng and its maximum size is limited to have good contrast in neutron radiography image of ginseng root. Thus, a preliminary radiographic study was performed to find the proper size of ginseng pot using the NR facility of HANARO. Several pots will be prepared for young ginsengs and they will be examined for about one year

230

Computed vs. conventional radiography for detecting fatigue cracks in riveted lap joints of aeronautical grade hybrid fiber-metal laminate Glare  

International Nuclear Information System (INIS)

This study aimed at assessing the capability of three different radiographic approaches (two computed or digital, and one conventional or analogous) for imaging fatigue cracks in riveted lap joints of composite fiber-metal laminate Glare. These structural joints are unique in the sense that fatigue cracks develop mainly at the faying surfaces of Glare sheets, so that visual detection is largely prevented and nondestructive inspection becomes mandatory. For this purpose, a round-robin programme comprising several industrial and research centers that employ X-ray radiography routinely to inspect high-demanding equipments, components and structures was conducted. (authors)

231

On the use of computed radiography plates for quality assurance of intensity modulated radiation therapy dose distributions  

International Nuclear Information System (INIS)

Purpose: As traditional film is phased out in most radiotherapy centers, computed radiography (CR) systems are increasingly being purchased as a replacement. CR plates can be used for patient imaging, but may also be used for a variety of quality assurance (QA) purposes and can be calibrated in terms of dose. This study looks at their suitability for verification of intensity modulated radiation therapy (IMRT) dose distributions. Methods: A CR plate was calibrated in terms of the relative dose and the stability of response over 1 year was studied. The effect of exposing the CR plate to ambient light and of using different time delays before scanning was quantified. The CR plate was used to verify the relative dose distributions for ten IMRT patients and the results were compared to those obtained using a two dimensional (2D) diode array. Results: Exposing the CR plate to 10 s of ambient light between irradiation (174 cGy) and scanning erased approximately 80% of the signal. Changes in delay time between irradiation and scanning also affected the measurement results. The signal on the plate was found to decay at a rate of approximately 3.6 cGy/min in the first 10 min after irradiation. The use of a CR plate for IMRT patient-specific QA resulted in a significantly lower distance to agreement (DTA) and gamma pass rate than when using a 2D diode array for the measurement. This was primarily due to the over-response of the CR phosphor to low energy scattered radiation. Forhor to low energy scattered radiation. For the IMRT QA using the CR plate, the average gamma pass rate was 97.3%. For the same IMRT QA using a diode array, the average gamma pass rate was 99.7%. The gamma criteria used were 4% dose difference and 4 mm DTA for head and neck treatments and 3% dose difference and 3 mm DTA for prostate treatments. The gamma index tolerance was 1. The lowest 10% of the dose distribution was excluded from all gamma and DTA analyses. Conclusions: Although the authors showed that CR plates can be used for patient specific IMRT QA, the practical problems such as the over-response to low energy scatter and signal fading with light exposure and time mean that alternative detectors such as radiochromic film or diode arrays will be a more sensible choice for most radiotherapy departments.

232

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)

233

Neutron radiography  

International Nuclear Information System (INIS)

The objective was to demonstrate the main characteristics of the neutron radiography technique, which has been developed in the Nuclear Physics Department of the IPEN-CNEN-SP. Its employment, in technology varies enormously and includes among others, the inspection of the hydrogen-rich substances, highly radioactive materials, etc. The indirect conversion method with Dysprosium screen was employed. The experimental arrangement used was a neutron collimator installed in the bottom of the IEA-R1 Nuclear Research Reactor pool. Several samples were analysed which were exposed in a neutron flux ? 107 n/s.cm2 during 10 minutes. The obtained results confirm the main characteristics of this technique as well as its viability to be developed in this reactor. (author)

234

Radiography exposure  

International Nuclear Information System (INIS)

This chapter, the reader will introduce with basic knowledge on radiography exposure. All the code and standard must give a specification on density or their range that can accepted. So the result outside the specification usually will be unacceptable and this can effected the time, cost and energy of the radiographer. So, for radiographer, they must work carefully to produce a good result and one way to solve this problem is through good exposure. The more the exposure can make a film darker while the less exposure can make the radiograph not enough density. So, through this chapter, the reader can know detailed how to manage this problem. As mention earlier, this technique is a combination between theories and practical, so, here theory is a main part to make the practical successful.

235

Digital radiography  

International Nuclear Information System (INIS)

Digital radiography is a generally accepted term comprising all X-ray image systems producing a projected image which resembles the conventional X-ray film image, and which are linked to any type of digital image processing. Fundamental criteria of differentiation are based on the production and detection method of the X-ray image. Various systems are employed, viz. the single-detector, line-detector or fanbeam detector and the area-beam or area-detector image converters, which differ from one another mainly in the manner of conversion of the radiation produced by the X-ray tube. The article also deals with the pros and cons of the various principles, the multitude of systems employed, and the varying frequency of their use in X-ray diagnosis work. (orig.)

236

Design analysis on composite target of high energy multi-pulse radiography  

International Nuclear Information System (INIS)

The analytic theory of the energy deposition of electron beam on the conversion target and the design approach for the composite target are presented. the high temperature plasma formed in the simple target would eject along positive and negative axial directions and make the target perforated. In the same beam energy, the beam with larger focal spot makes smaller ablated cavities with curl edge in the target, but the beam with smaller spot makes larger ones with relativly smooth edge. The composite target and the modified composite target can bear continuous strikes of 2-3 beam pulses. The Monte Carlo simulation shows that the spot size of Bremsstrahlung sources are the same as the electron beam spot size on the target, thus the composite target can be used in the multi-pulse radiography. (authors)

237

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 wer...

Weise Kuno; Pereira Philippe L; Dietz Klaus; Eingartner Christoph; Schmal Hagen; Südkamp Norbert P; Rolauffs Bernd; Bahrs Christian; Lingenfelter Erich; Helwig Peter

2009-01-01

238

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

239

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

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  

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

 
 
 
 
241

Automatic Registration of CT Volumes and Dual-Energy Digital Radiography for Detection of Cardiac and Lung Diseases  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We are investigating image processing and analysis techniques to improve the ability of dual-energy digital radiography (DR) for the detection of cardiac calcification. Computed tomography (CT) is an established tool for the diagnosis of coronary artery diseases. Dual-energy digital radiography could be a cost-effective alternative. In this study, we use three-dimensional (3D) CT images as the “gold standard” to evaluate the DR X-ray images for calcification detection. To this purpose, we...

Fei, Baowei; Chen, Xiang; Wang, Hesheng; Sabol, John M.; Dupont, Elena; Gilkeson, Robert C.

2006-01-01

242

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

243

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

244

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

245

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2012-12-15

246

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

247

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

International Nuclear Information System (INIS)

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

248

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

249

Radiography for intensive care: participatory process analysis in a PACS-equipped and film/screen environment  

Science.gov (United States)

If new technology is introduced into medical practice it must prove to make a difference. However traditional approaches of outcome analysis failed to show a direct benefit of PACS on patient care and economical benefits are still in debate. A participatory process analysis was performed to compare workflow in a film based hospital and a PACS environment. This included direct observation of work processes, interview of involved staff, structural analysis and discussion of observations with staff members. After definition of common structures strong and weak workflow steps were evaluated. With a common workflow structure in both hospitals, benefits of PACS were revealed in workflow steps related to image reporting with simultaneous image access for ICU-physicians and radiologists, archiving of images as well as image and report distribution. However PACS alone is not able to cover the complete process of 'radiography for intensive care' from ordering of an image till provision of the final product equals image + report. Interference of electronic workflow with analogue process steps such as paper based ordering reduces the potential benefits of PACS. In this regard workflow modeling proved to be very helpful for the evaluation of complex work processes linking radiology and the ICU.

Peer, Regina; Peer, Siegfried; Sander, Heike; Marsolek, Ingo; Koller, Wolfgang; Pappert, Dirk; Hierholzer, Johannes

2002-05-01

250

Equipment of gamma radiography  

International Nuclear Information System (INIS)

The requirements and conditions necessary to gamma radiography equipment are presented. The exigencies of construction and approval of portable, mobile and fixed equipments for gramma radiography are presented. (E.G.)

251

Comparison of radiography, computed tomography and magnetic resonance imaging in the detection of sacroiliitis for ankylosing spondylitis  

International Nuclear Information System (INIS)

Purpose: To evaluate characteristics of sacroiliitis on MR imaging and to compare the MR images with findings obtained by conventional radiography and CT in patients with ankylosing spondylitis (AS). Materials and methods: Twenty-four AS patients were recruited. In each patient the conventional radiography, CT and MR imaging were completed within a week interval. In pre-contrast MR examination, SE T1, FSE T2 and GR T2* weighted images were chosen. Post-contrast MR examination was performed using the same SE T1 sequence as the pre-contrast MR examination. Another 9 healthy volunteers underwent the same examinations as the pre-contrast MR imaging. Results: MR imaging directly showed the cartilage in the synovial compartment as a thin linear or dot zone of intermediate signal intensity on both T1 and T2 weighted images in all 16 sacroiliac (SI) joints of the 8 volunteers. Of the 11 SI joints in 9 volunteers, focal fat signal intensities were observed as higher signal intensity on both T1, T2 or T2* weighted images in the areas of bone marrow. Of 42 SI joints in 24 AS patients were observed the cartilage abnormalities. Cartilage abnormalities were shown either to loss of the normal thin zone of intermediate signal intensity or to become thick, irregular and crooked intermediate signal intensity on T1 or T2 weighted images. The sacror T2 weighted images. The sacroiliitis diagnosed by MR imaging and CT were significantly more than those by radiography (P<0.001). Conclusion: Comparing with radiographs, both CT and MR are helpful to the diagnosis of sacroiliitis in patients with AS. MR can reveal the abnormality of cartilage and bone marrow edema, which cannot shown on both CT and radiographs. Normal variant should be considered as the explanation for the fat accumulation in the bone marrow. The crooked intermediate signal should be considered as another abnormal cartilage sign

252

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-07-01

253

Evidence-based radiography  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 N...

Hafslund, Bjørg; Clare, Judith; Graverholt, Birgitte; Nortvedt, Monica Wammen

2008-01-01

254

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)

255

Advancements in CR radiography  

International Nuclear Information System (INIS)

Digital radiography using storage phosphor plates is known as ''Computed Radiography'' or CR for short. This ''filmless'' technique is for many applications an excellent alternative for traditional X-ray films. In addition to the reduced cost of consumables, CR technology is more sensitive to radiation, thus requiring a lower exposure dose and shorter exposure times. The high dynamic range of CR makes it a 'more forgiving' technology than Film Radiography resulting in fewer retakes. In 2005 the European Standard EN 14784 and the ASTM 2445/2446 and have been published. These standards describe a qualification method and a classification for CR systems- additionally CR was also adopted in ASME V. CR technology is introduced in more and more applications for instance in the Oil and Gas and Chemical Industry (Corrosion monitoring weld inspection), in the Aerospace Industry (Castings Inspection) and in security applications. One of the main advantages of CR is the digital data format. Digital data give the user a better data access, allow for data sharing and networking, and they enable archiving easy data retrieval. This makes it possible for the user to rethink his data management and his workflow. With the current technolog inspections and evaluations can for instance be done remotely. The adoption of the DICONDE data format in the NDT Industry will further promote the digital format. GEIT has developed an NDT multimodal software platform for reviewing, analyzing, archie platform for reviewing, analyzing, archiving and sharing digital inspection information. It can be configured for the specific user needs and contains application specific tools to improve efficiency and reproductibility of results. One example is the Wall Thickness Measurement Tool that was validated by the BAM Institute. This presentation gives an overview of the current status of the CR Technology, the CRstandards and some successful applications. It also shows some of the advantages and benefits that the software brings to the inspection process. (author)

256

Analysis of the impact of digital tomosynthesis on the radiological investigation of patients with suspected pulmonary lesions on chest radiography  

International Nuclear Information System (INIS)

To assess the impact of digital tomosynthesis (DTS) on the radiological investigation of patients with suspected pulmonary lesions on chest radiography (CXR). Three hundred thirty-nine patients (200 male; age, 71.19 ± 11.9 years) with suspected pulmonary lesion(s) on CXR underwent DTS. Two readers prospectively analysed CXR and DTS images, and recorded their diagnostic confidence: 1 or 2 = definite or probable benign lesion or pseudolesion deserving no further diagnostic workup; 3 = indeterminate; 4 or 5 = probable or definite pulmonary lesion deserving further diagnostic workup by computed tomography (CT). Imaging follow-up by CT (n = 76 patients), CXR (n = 256) or histology (n = 7) was the reference standard. DTS resolved doubtful CXR findings in 256/339 (76 %) patients, while 83/339 (24 %) patients proceeded to CT. The mean interpretation time for DTS (mean ± SD, 220 ± 40 s) was higher (P < 0.05; Wilcoxon test) than for CXR (110 ± 30 s), but lower than CT (600 ± 150 s). Mean effective dose was 0.06 mSv (range 0.03-0.1 mSv) for CXR, 0.107 mSv (range 0.094-0.12 mSv) for DTS, and 3 mSv (range 2-4 mSv) for CT. DTS avoided the need for CT in about three-quarters of patients with a slight increase in the interpretation time and effective dose compared to CXR. (orig.)

257

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.)

258

Compton radiography, 3  

International Nuclear Information System (INIS)

The compton radiography aims at collection of depth information by recording with a scinticamera those Compton rays that have resulted from scattering of a monoenergetic gamma beam by a volume of interest. Appreciably clear clinical scinti-tomograms were obtained of the chest wall, and intrathoracic structures such as the lungs, intrapulmonary pathologies and mediastinum. This was achieved without any computer assistance for image reconstruction such as those in the case of XCT. Apparently, suitable corrections of the attenuations of the primary monoenergetic gamma rays and secondary Compton rays would greatly improve the image quality, and imaging time and radiation exposure as well. This technic is simple in principle, relatively cheap, and yet prospective of development of stereoptic fluoroscopy that would be extremely helpful in guiding such procedures as visceral biopsies. (auth.)

259

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.)

260

Comparison of whole-body 64-slice multidetector computed tomography and conventional radiography in staging of multiple myeloma  

International Nuclear Information System (INIS)

This study compares the sensitivity of whole-body multidetector CT (MDCT) and conventional radiography (CR) in the staging of multiple myeloma (MM). Twenty-nine patients with MM underwent a staging examination both by MDCT and CR. CT examination was performed with a collimation of 64 x 0.6 mm, a tube potential of 100 kVp, an effective tube current-time product of 100 mAs and automatic dose modulation as low-dose protocol. Number, size and diagnostic confidence of osteolytic lesions were determined and compared. The effective dose of MDCT and CR was assessed. Using MDCT, the detection of osteolysis was increased seven-fold concerning the spine. Ninety-seven lesions in 18 patients were detected exclusively by MDCT. The detection rate concerning the spine, pelvic skeleton and thoracic cage was significantly higher (p?0.001), and diagnostic confidence was increased by MDCT (p<0.02) compared to CR. Therapy was changed after MDCT in 18.2% of the patients with a clinical suspicion of progressive disease. The estimated effective dose of MDCT (4.8 mSv) and CR (1.7 mSv) was comparable. In conclusion, MDCT has a significantly higher sensitivity and reliability in the detection of osteolysis than CR and can be recommended as standard imaging method in the staging of MM. (orig.)

 
 
 
 
261

Comparison of whole-body 64-slice multidetector computed tomography and conventional radiography in staging of multiple myeloma  

Energy Technology Data Exchange (ETDEWEB)

This study compares the sensitivity of whole-body multidetector CT (MDCT) and conventional radiography (CR) in the staging of multiple myeloma (MM). Twenty-nine patients with MM underwent a staging examination both by MDCT and CR. CT examination was performed with a collimation of 64 x 0.6 mm, a tube potential of 100 kVp, an effective tube current-time product of 100 mAs and automatic dose modulation as low-dose protocol. Number, size and diagnostic confidence of osteolytic lesions were determined and compared. The effective dose of MDCT and CR was assessed. Using MDCT, the detection of osteolysis was increased seven-fold concerning the spine. Ninety-seven lesions in 18 patients were detected exclusively by MDCT. The detection rate concerning the spine, pelvic skeleton and thoracic cage was significantly higher (p{<=}0.001), and diagnostic confidence was increased by MDCT (p<0.02) compared to CR. Therapy was changed after MDCT in 18.2% of the patients with a clinical suspicion of progressive disease. The estimated effective dose of MDCT (4.8 mSv) and CR (1.7 mSv) was comparable. In conclusion, MDCT has a significantly higher sensitivity and reliability in the detection of osteolysis than CR and can be recommended as standard imaging method in the staging of MM. (orig.)

Kroepil, Patric; Fritz, Lars B.; Blondin, Dirk; Moedder, Ulrich; Cohnen, Mathias [Institut fuer Diagnostische Radiologie der Universitaet Duesseldorf, Duesseldorf (Germany); Fenk, Roland; Kobbe, Guido [Onkologie und Klinische Immunologie der Universitaet Duesseldorf, Klinik fuer Haematologie, Duesseldorf (Germany)

2008-01-15

262

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)

263

Specific radiography technique  

International Nuclear Information System (INIS)

Beside radiography testing using x-ray machine and gamma source, there are several technique that developed specifically to complete the testing that cannot be done with the two earlier. This technique was specific based on several factor, for the example, the advantages of neutron and electron using to show the image was unique compare to x-ray and gamma. Besides that, these special radiography techniques maybe differ in how to detect the radiation get through the object. These technique can used to inspect thin or specimen that contained radioactive material. There are several technique will discussed in this chapter such as neutron radiography, electron radiography, fluoroscopy and also autoradiography.

264

Multiple-image radiography  

International Nuclear Information System (INIS)

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

265

Security Analysis of Cloud Computing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper produces a baseline security analysis of the Cloud Computing Operational Environment in terms of threats, vulnerabilities and impacts. An analysis is conducted and the top three threats are identified with recommendations for practitioners. The conclusion of the analysis is that the most serious threats are non-technical and can be solved via management processes rather than technical countermeasures

Carlson, Frederick R.

2014-01-01

266

Simulation of the radiography formation process from CT patient volume  

International Nuclear Information System (INIS)

The aim of this work is to develop an algorithm to simulate the radiographic image formation process using volumetric anatomical data of the patient, obtained from 3D diagnostic CT images. Many applications, including radiographic driven surgery, virtual reality in medicine and radiologist teaching and training, may take advantage of such technique. The designed algorithm has been developed to simulate a generic radiographic equipment, whatever oriented respect to the patient. The simulated radiography is obtained considering a discrete number of X-ray paths departing from the focus, passing through the patient volume and reaching the radiographic plane. To evaluate a generic pixel of the simulated radiography, the cumulative absorption along the corresponding X-ray is computed. To estimate X-ray absorption in a generic point of the patient volume, 3D interpolation of CT data has been adopted. The proposed technique is quite similar to those employed in Ray Tracing. A computer designed test volume has been used to assess the reliability of the radiography simulation algorithm as a measuring tool. From the errors analysis emerges that the accuracy achieved by the radiographic simulation algorithm is largely confined within the sampling step of the CT volume. (authors)

267

Analysis of muon radiography of the Toshiba nuclear critical assembly reactor  

Energy Technology Data Exchange (ETDEWEB)

A 1.2?×?1.2 m{sup 2} 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.

Morris, C. L.; Bacon, Jeffery; Borozdin, Konstantin; Fabritius, J. M.; Perry, John; Ramsey, John [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Ban, Yuichiro; Izumi, Mikio; Sano, Yuji; Yoshida, Noriyuki [Toshiba Corporation, 8 Shinsugita-cho, Isogo-ku, Yokohama 235-8523 (Japan); Miyadera, Haruo [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Toshiba Corporation, 8 Shinsugita-cho, Isogo-ku, Yokohama 235-8523 (Japan); Mizokami, Shinya; Otsuka, Yasuyuki; Yamada, Daichi [Tokyo Electric Power Company, 1-1-3 Uchisaiwai-cho, Chiyoda-ku, Tokyo (Japan); Sugita, Tsukasa; Yoshioka, Kenichi [Toshiba Corporation, 4-1 Ukishima-cho, Kawasaki-ku, Kawasaki 210-0862 (Japan)

2014-01-13

268

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)

269

Biomechanical strength versus spinal trabecular bone strucure assessed using contact radiography and texture analysis  

Science.gov (United States)

Cubic specimens (N equals 26, 12 mm multiplied by 12 mm multiplied by 12 mm) of human vertebrae were cut along three orthogonal anatomical orientations, i.e. superior-inferior (SI), medial-lateral (MI) and anterior-posterior (AP). Contact radiographs of the bone cubes along these orientations were obtained and digitized using a laser scanner with a pixel size of 50 mm. A standardized digital image processing procedure was designed to assess trabecular bone structure. Global gray level thresholding and local thresholding algorithms were used to extract the trabecular bone network. Apparent trabecular bone fraction (ABV/TV), apparent trabecular thickness (I.Th), mean intercept separation (I.Sp), and number of nodes (N.Nd) were measured from the extracted trabecular network. Box counting based fractal dimension (Fr.D) of the trabecular bone pattern was also measured. Quantitative computed tomography (QCT) was then used to obtain bone mineral density (BMD). The specimens were further tested in compression along the same orthogonal orientations, and the corresponding Young's modulus (YM) were calculated. Paired t-test showed that the mean value of texture parameters (except ABV/TV) and YM along the SI orientation were significantly different (p less than 0.05) from those along the ML and AP orientations. In comparison, the mean values along ML and AP orientations were not significantly different. Correlation coefficients from linear regression and non-parametric correlation between YM, BMD and texture parameters showed a wide range, but they differed depending on the orthogonal plane of radiographic projection and the direction of biomechanical testing. In conclusion, trabecular texture parameters correlated significantly with BMD and YM. Trabecular texture parameters reflect the anisotropy or trabecular structure.

Ouyang, Xiaolong; Lin, John C.; Link, Thomas M.; Augat, Peter; Lu, Ying; Newitt, David; Lang, Thomas; Genant, Harry K.; Majumdar, Sharmila

1997-04-01

270

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

Directory of Open Access Journals (Sweden)

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

Njeh Christopher F

2012-03-01

271

Intra-arterial digital subtraction angiography with extra-large fields using a computed radiography system in evaluating peripheral vascular disease.  

Science.gov (United States)

The authors evaluated the usefulness of intra-arterial digital subtraction angiography (DSA) with extra-large field sizes using a computed radiography (CR) system in evaluating peripheral vascular disease (PVD). Intra-arterial DSA using CR was performed in 55 patients with suspected PVD. A 4 F catheter was advanced into the abdominal aorta via the transbrachial approach and 90 ml of contrast medium was injected during six exposures using a long leg changer mounting a total of 18 imaging plates on six surfaces. Visualization of the superficial femoral and popliteal arteries was judged as diagnostic in all cases. The abdominal aorta, iliac arteries, and subtrifurcation were also visualized in most cases, but visualization was suboptimal in some cases. As a complication, median nerve palsy occurred in one case. This technique is thought to be a useful method for evaluating PVD because of the advantages of a large field of view and wide exposure latitude, in spite of its relatively long processing time. PMID:8988500

Hasuo, K; Mizushima, A; Mihara, F; Hashiguchi, N; Murayama, S; Uchino, A; Matsumoto, S; Gibo, M; Torii, Y; Komori, K; Masuda, K

1996-01-01

272

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

International Nuclear Information System (INIS)

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

273

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

274

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 ...

275

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)

276

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

277

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)

278

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

279

Analysis on Cloud Computing  

Directory of Open Access Journals (Sweden)

Full Text Available Cloud storage enables users to remotelystore their data and enjoy the on-demand high quality cloud applications without the burden of local hardware and software management. Though the benefits are clear, such a service is also relinquishing users’ physical possession of their outsourced data, which inevitably poses new security risks towards the correctness of the data in cloud. In order to address this new problem and further achieve a secure and dependable cloud storage service, we propose in this paper a flexible distributed storage integrity auditing mechanism, utilizing the homomorphic token and distributed erasure-coded data. The proposed design allows users to audit the cloud storage with very lightweight communication and computation cost. The auditing result not only ensures strong cloud storage correctness guarantee, but also simultaneously achieves fast data error localization, i.e., the identification of misbehaving server. Considering the cloud data are dynamic in nature, the proposed design further supports secure and efficient dynamic operations on outsourced data, including block modification, deletion, and append.

S.PATHRO

2013-05-01

280

Affective Computing and Sentiment Analysis  

CERN Document Server

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

Ahmad, Khurshid

2011-01-01

 
 
 
 
281

Experiments on neutron radiography  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the neutron-radiography research activities in Nuclear Energy Unit (UTN) as a trial before a neutron-radiography service can routinely be given. This trial neutron-radiography research encompasses the design and construction of a facility (NuR 1), collimator and the exposure system, as well as measurements of neutron and gamma dose-distribution, neutron-beam properties in NuR 1 and characteristics of the image recorder. A few problems arose in the early stage of work and the action taken to overcome these are also mentioned. Finally, methods of increasing the quality of the image are proposed and attempted. This project has given some important information so as to enable the construction of a permanent facility (Nur 2) and the execution of a neutron-radiography service.

Abdul Ghaffar Ramli; Azali Muhamad; Wan Ruslan Yusof; Ahmad Sabri Abdul Razak; Jamal Khaer Ibrahim; Rosley Jaafar (PUSPATI, Selangor (Malaysia))

1984-12-01

282

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.

2006-09-01

283

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

284

In situ analysis of equiaxed growth of aluminium-nickel alloys by x-ray radiography at ESRF  

International Nuclear Information System (INIS)

We present results obtained at the ID19 beamline of the European Synchrotron Radiation Facility (ESRF) by synchrotron x-ray radiography during the solidification of Al-Ni alloys. We focus on columnar dendritic and equiaxed solidification, and the transition between the two regimes. The columnar to equiaxed transition is a critical and still pending issue in metallurgy. By making use of the high potential of synchrotron experimental tools for in situ and real-time characterization of the solid-liquid interface during directional solidification, we were able to provide insight into key physical phenomena, in particular, sedimentation, interaction and arrangement of equiaxed grains

285

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.)

286

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 wer 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.)

287

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

288

Comparison of conventional radiography combined with ultrasonography versus nonenhanced helical computed tomography in evaluation of patients with renal colic.  

Science.gov (United States)

The aim of this study is to determine whether kidneys ureters bladder X-ray (KUB) film combined with ultrasound (US) can be effectively used in evaluation of renal colic and miss stones with clinically significant size identified on nonenhanced computed tomography (NECT) in patients with urolithiasis. This retrospective study evaluated the clinical and radiological records of 300 patients at our institution undergoing KUB and/or US and/or NECT for the evaluation of renal colic from June 2007 to December 2010. Of patients with negative findings on KUB and/or US, 22 had renal stones on NECT (mean size 4.4 mm, range 3-8), 3 had lower ureteral stone (mean size 3.3 mm, range 2-5). In patients with isolated suspicious renal ectasia without stone image, two had renal stone on NECT (mean size 4 mm, range 2-6), 5 had upper ureteral stone (mean size 4.4 mm, range 4-6), 7 had middle ureteral stone (mean size 3.7 mm, range 3-4) and 14 had lower ureteral stone (mean size 4 mm, range 2-6). The cost-effective and almost radiation-free combination of KUB and US should be preferred for diagnosis of urolithiasis, as it detects most of the ureteral and renal calculi which are clinically significant. PMID:22415439

Ekici, Sinan; Sinanoglu, Orhun

2012-10-01

289

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.))

290

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

Science.gov (United States)

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.

Pignol, Jean-Philippe; Abbe, Jean-Charles; Thellier, Michel; Stampfler, Aimé

1994-12-01

291

Proceedings of 7th short conference on neutron radiography  

International Nuclear Information System (INIS)

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

292

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

293

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

294

Licensing of industrial radiography installation  

International Nuclear Information System (INIS)

This norm establishes the requirements for Industrial Radiography Installations Licensing and the procedures for acquisition and transfer of radioactive sources and/or X-ray equipment used in Industrial Radiography. (O.M.)

295

Bone X-Ray (Radiography)  

Medline Plus

Full Text Available ... are the limitations of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray ( ... leg (shin), ankle or foot. top of page What are some common uses of the procedure? View ...

296

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)

297

Analysis of neutron attenuation in boron-alloyed stainless steel with neutron radiography and JEN-3 gauge  

International Nuclear Information System (INIS)

This paper concerns the neutron attenuation behavior of boron-alloyed stainless steels, and quantitative estimations of secondary effects on the neutron transmission measurements, such as beam hardening, background and micro-structure of neutron absorber causing a decrease in the total macroscopic cross-sections. Systematic thermal neutron transmission measurements of boron-alloyed steel plates have been performed at different neutron radiography facilities and at a portable gauge called JEN-3, which is a practical neutron transmission setup for industrial demands in non-destructive material inspection. In addition, MCNP (Monte Carlo Neutron Particle transport) simulations were performed for a better understanding of the experimental results, the secondary factors affecting the total macroscopic cross-sections, and the characteristics of the JEN-3 gauge. The detectable thickness limit for 1.88 wt% natural boron-alloyed steel plates was determined as 1-1.5 cm depending on the contributions of the secondary factors in each facility

298

Accuracy of conventional panoramic radiography and stereo radiography in determining the position of impacted maxillary canines  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: In addition to conventional radiography, several other techniques such as stereoradiography have so far been proposed to determine the position of impacted maxillary canines. The purpose of this study was to evaluate the diagnostic value of panoramic radiography and stereoradiography for determining the position of impacted maxillary canines.Materials and Methods: This was a prognostic, cross sectional study. A total of 30 impacted maxillary canines in 23 patients candidated for surgery were included. Four well coordinated observers separately determined the position of impacted maxillary canines using both panoramic radiography and stereoradiography. In the next phase, the exact position of impacted canines were determined through surgical exploration. Mc-Nemar and kappa index were applied for statistical data analysis. (? = 0.05.Results: The rate of correct diagnosis in stereoradiography and conventional radiography was 93.35% and 60.82% respectively which demonstrated a statistically significant difference. With each method, there were no significant differences among observers. Sensitivity and specificity with stereoradiography were calculated 91.98% and 94.78% respectively. With conventional radiography however these values dropped to 49.90% and 74.11% respectively.Conclusion: Stereoradiography seems quite reliable for determining the position of impacted maxillary canines. On the contrary, conventional radiography per se does not look precise enogh to determin the position of impacted maxillary canines. Key words: Stereoradiography, Panoramic, Impacted tooth, Canine, Maxilla.

M Abdinian

2010-01-01

299

Real-time radiography  

Energy Technology Data Exchange (ETDEWEB)

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.

Bossi, R.H.; Oien, C.T.

1981-02-26

300

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

 
 
 
 
301

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

302

Spatially coded backscatter radiography  

International Nuclear Information System (INIS)

Conventional radiography requires access to two opposite sides of an object, which makes it unsuitable for the inspection of extended and/or thick structures (airframes, bridges, floors etc.). Backscatter imaging can overcome this problem, but the indications obtained are difficult to interpret. This paper applies the coded aperture technique to gamma-ray backscatter-radiography in order to enhance the detectability of flaws. This spatial coding method involves the positioning of a mask with closed and open holes to selectively permit or block the passage of radiation. The obtained coded-aperture indications are then mathematically decoded to detect the presence of anomalies. Indications obtained from Monte Carlo calculations were utilized in this work to simulate radiation scattering measurements. These simulated measurements were used to investigate the applicability of this technique to the detection of flaws by backscatter radiography

303

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

304

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 ( ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

305

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 ...

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 ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

307

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

308

Radiography in archaeology  

Science.gov (United States)

Radiography is a potent tool for archaeologists, conservators and archaeological scientists concerned with the investigation of the artefacts and ecofacts recovered from excavations. Increasingly specialists are refining the information they can recover from archaeological materials; in the pre-war years, mummies, and other skeletal material were of primary interest but since the war, all materials have been examined, although the emphasis remains on ferrous objects. Although much information can be recovered using basic equipment, increasingly sophisticated techniques are being applied. This paper reviews the use of radiography in archaeology and describes the techniques of primary value to archaeologists.

Corfield, M.

1995-11-01

309

Progress in proton scattering radiography  

International Nuclear Information System (INIS)

Some preliminary results of investigations to obtain three-dimensional images of density distribution in ob ects using the nuclear scattering of medium energy (around 1 GeV) protons are presented. A system has been constructed and operated at CERN including four two-coordinates multiwire proportional chambers, a fast wire-per-wire digital readout and transfer, ano an on-line vertex finding micro-programmed computer for data reduction. Data have been taken using as an object a dead human head. Images showing the density distribution in several slices one cm thick are given. The proton scattering radiography is concluded to be of great interest as compared with computer assisted tomography scanners, for the following reasons: a fully 3-dimensional image, the radiation level for the same contrast is reduced (about 30O m Rad), the hydrogen content measurement may bring in some information that cannot be obtained with X-rays

310

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

311

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

312

Accelerator-based neutron tomography cooperating with X-ray radiography  

International Nuclear Information System (INIS)

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.

313

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

314

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.

315

Compton radiography, 2  

International Nuclear Information System (INIS)

Compton radiography, a tomographic technic with Compton-scattered rays of a monochromatic gamma ray beam, was feasible of tomographing a chest phantom. The result suggested that the technic could be extended to imaging of the lung and the surrounding structures of the chest wall, mediastinum and liver in Compton tomographic mode. (auth.)

316

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

317

Apparatus for radiography  

International Nuclear Information System (INIS)

This patent describes an arrangement of equipment for radiography which enables an increase in contrast sensitivity with a corresponding decrease in radiation exposure. The arrangement consists basically of a radiation source, a collimator and a scintillator. The latter is optically coupled to a self-scanning, integrated row of photodiodes. (Th.W.J.P.)

318

Ultrasonography X gamma radiography  

International Nuclear Information System (INIS)

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

319

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

320

Introduction to radiography  

International Nuclear Information System (INIS)

The contents of this chapter are follows - Radiology in Malaysia: Properties and Effects of X-ray, Roles of Radiology Department: Imaging Modalities in the Radiology Department: Imaging Modalities in the Imaging Department: Imaging Modalities in the Imaging Department: Conventional Radiography of Today

 
 
 
 
321

CGAT: computational genomics analysis toolkit  

Science.gov (United States)

Summary: 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. Availability: The toolkit is freely available from http://github.com/CGATOxford/cgat Contact: andreas.heger@dpag.ox.ac.uk 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

2014-01-01

322

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

Science.gov (United States)

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

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

2015-02-01

323

Comparison of conventional radiography and MDCT in suspected scaphoid fractures  

Science.gov (United States)

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

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

2015-01-01

324

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)

325

Digital radiography simulation for industrial applications with MCNPX  

International Nuclear Information System (INIS)

The energy dependent response of a BaFBr Image Plate detector was modeled and introduced in MCNPX radiography tally input. To convert MCNPX radiography tally output in 16 bits digital images, a post processing program called PROGRAMA IMAGEM is presented. Simulate images of a steel tube containing corrosion alveoli and grinded defects were compared with experimental images. The radiography technique used in all tests was double wall single image, DWSI, using an Iridium source (192Ir) touching the adjacent wall. Visual and perfilometric analysis showed that the methodology used for sensible material simulation and data post-processing makes simulate digital images comparable to experimental images. (author)

326

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

327

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

328

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

329

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

330

Quantitative film radiography  

International Nuclear Information System (INIS)

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

331

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)

332

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

333

Digital radiography in space.  

Science.gov (United States)

With the permanent habitation of the International Space Station, the planning of longer duration exploration missions, and the possibility of space tourism, it is likely that digital radiography will be needed in the future to support medical care in space. Ultrasound is currently the medical imaging modality of choice for spaceflight. Digital radiography in space is limited because of prohibitive launch costs (in the region of $20,000/kg) that severely restrict the volume, weight, and power requirements of medical care hardware. Technological increases in radiography, a predicted ten-fold decrease in future launch costs, and an increasing clinical need for definitive medical care in space will drive efforts to expand the ability to provide medical care in space including diagnostic imaging. Normal physiological responses to microgravity, in conjunction with the high-risk environment of spaceflight, increase the risk of injury and could imply an extended recovery period for common injuries. The advantages of gravity on Earth, such as the stabilization of patients undergoing radiography and the drainage of fluids, which provide radiographic contrast, are unavailable in space. This creates significant difficulties in patient immobilization and radiographic positioning. Gravity-dependent radiological signs, such as lipohemarthrosis in knee and shoulder trauma, air or fluid levels in pneumoperitoneum, pleural effusion, or bowel obstruction, and the apical pleural edge in pneumothorax become unavailable. Impaired healing processes such as delayed callus formation following fracture will have implications on imaging, and recovery time lines are unknown. The confined nature of spacecraft and the economic impossibility of launching lead-based personal protective equipment present significant challenges to crew radiation safety. A modified, free-floating radiographic C-arm device equipped with a digital detector and utilizing teleradiology support is proposed as a theoretical solution to help overcome many of these difficulties. PMID:12056679

Hart, Rob; Campbell, Mark R

2002-06-01

334

CCD digital radiography system  

Science.gov (United States)

Amorphous silicon flat-panel detector is the mainstream used in digital radiography (DR) system. In latest years, scintillation screen coupled with CCD DR is becoming more popular in hospital. Compared with traditional amorphous silicon DR, CCD-DR has better spatial resolution and has little radiation damage. It is inexpensive and can be operated easily. In this paper, A kind of CCD based DR system is developed. We describe the construction of the system, the system performances and experiment results.

Wang, Yi; Kang, Xi; Li, Yuanjing; Cheng, Jianping; Hou, Yafei; Han, Haiwei

2009-07-01

335

Compton radiography, 1  

International Nuclear Information System (INIS)

Tomographic images of an object are obtainable by irradiating it with a collimated beam of monochromatic gamma rays and recording the resultant Compton rays scattered upward at right angles. This is the scattered-ray principle of the formation of a radiation image that differs from the traditional ''silhouette principle'' of radiography, and that bears prospects of stereopsis as well as cross-section tomography. (Evans, J.)

336

Optimisation in general radiography  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Radiography using film has been an established method for imaging the internal organs of the body for over 100 years. Surveys carried out during the 1980s identified a wide range in patient doses showing that there was scope for dosage reduction in many hospitals. This paper discusses factors that need to be considered in optimising the performance of radiographic equipment. The most important factor is choice of the screen/film combination, and the preparation of automatic exposure control d...

Cj, Martin

2007-01-01

337

Panoramic dental radiography  

International Nuclear Information System (INIS)

Apparatus is described for improving the handling rate of patients in panoramic dental radiography when tube head-camera assembly of a low silhouette panoramic dental X-ray machine is rotated for a scan in one direction only. This is effected by fast return of the tube head-camera assembly with its simultaneous elevation, thus facilitating the radiographed patient's exit from the machine and the entrance of another patient. Fast speed is about twice the scanning speed. (author)

338

Comparison of the accuracy of digital and conventional radiography in evaluation of curved canals lengths.  

Directory of Open Access Journals (Sweden)

Full Text Available Background and Aim: Proper shaping and cleaning of the root canal system is one of the most important aspects of endodontic treatment. To estimate the canal length before instrumentation in endodontic treatment, traditionally, conventional radiographic techniques and recently Direct Digital Radiography (DDR are applied. The application of computer technology to radiography has allowed less exposure time, image acquisition, manipulation, storage, retrieval, and transmission to remote sites in a digital format, elimination of wet processing and considerable reduction in the time lapse between image acquisition and display. The purpose of this study was to compare the accuracy of DDR versus conventional radiography in estimating endodontic file lengths of curved canals in first mandibular molars. Materials and Methods: In this test evaluation study, fourty extracted human first mandibular molars with root curvature were selected. Samples were divided into two groups: With root curvature less than 25? and more than 25?. Samples were mounted in plaster blocks and canal lengths were estimated by using DDR and conventional radiographs. Regression analysis and correlation coefficient were used to calculate statistical differences between the groups with P<0.05 as the limit of significance. Results: Conventional radiography was more precise in canals with less than 25 degrees curvature (P=0.160. While, DDR was more precise for canals with curvature more than 25 degrees (P=0.605. However, these differences were not statistically significant. Conclusion: The image quality of DDR system has improved to the point that it can now be used for estimating canal lengths, even for curved canals, with accuracy comparable to that of conventional radiography.

Ezoddini Ardakani F.

2005-07-01

339

A Petaflops Era Computing Analysis  

Science.gov (United States)

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

Preston, Frank S.

1998-01-01

340

Introduction to industrial radiography  

International Nuclear Information System (INIS)

For the first topic in this book, more on introduction to nondestructive testing, also a little bit on another technique such as magnetic testing, liquid penetrated, ultrasonic testing and others. This book mentions more on radiographic testing and for that, more details on this topic such as history, definition and devices that use in this technique. This radiography testing firstly started with the discovering of x-ray by Wilhelm Roentgen (1895). So, on 1913, David Coolidge successfully invented and developed x-ray tube that could made x-ray more intensified and produced highly penetration forces. Radiography in Malaysia firstly started two years after the discovery made by Wilhelm Roentgen when one hospital here used the x-ray machine for medical purposes. Besides using x-ray, radiography also used gamma rays, and for these purpose, they used Co-60 and Ir-192. Now, more company based on NDT established to provide a service on inspection pipe and others. For filled these requirement, radiographer must take an exam to make them expert and trained well to work in this field. There is no advantage using this technique or other technique. So that's why this book was published to make people understand what is radiographic testing truly.

 
 
 
 
341

Quality assurance in digital radiography  

International Nuclear Information System (INIS)

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

342

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

343

Digital radiography - from principles to practical testing  

International Nuclear Information System (INIS)

Digital radiography is broken down into two branches: storage luminescence technology and digitalization of existing films. The principles of both methods are presented in a short outline. The main advantages of this technology include decay-proof archiving that dispenses with film storage, computerized analysis of images using quantitative assessment standards, and improved display readability as compared to visual analysis. As a neutral authority, the Federal Institute for Materials Research and Testing (BAM) was charged with making an assessment of digital radiography by means of the approved ROC method. Based on an extensive collection of test pieces, the respective final result of the analysis was compared with the transmission images, i.e. digital data were compared with original films. (orig./MM)

344

Evaluation of knee-joint cartilage and menisci ten years after isolated and combined ruptures of the medial collateral ligament. Investigation by weight-bearing radiography, MR imaging and analysis of proteoglycan fragments in the joint fluid  

International Nuclear Information System (INIS)

Purpose: To compare radiography, MR imaging, and chemical analysis in posttraumatic knees. Material and Methods: Ten matched pairs with either isolated partial rupture of the medial collateral ligament or combined medial collateral ligament/anterior cruciate ligament rupture were compared with matched controls 10 years after trauma. Weight-bearing radiographys and MR examinations were compared with proteoglycan fragment concentrations in the joint fluid. Results: The chemical analyses were similar in both trauma groups. The radiographs showed mild signs of arthrosis in half the patients with combined injury. MR images showed almost all injuried knees to have degenerative changes of various degrees in the cartilage and menisci. More frequent and more advanced changes were found after combined injury than after isolated injury (p<0.01). There were no changes in the controls. Conclusion: MR imaging is the best method for detecting and differentiating early posttraumatic knee arthrosis. (orig.)

345

Real-time neutron radiography  

International Nuclear Information System (INIS)

The main objective of the present thesis was develop and get operational a real-time neutron radiography system, at the IPEN-CNEN/SP. This system is installed inside the shielding of an old facility, designed in 1988, for film radiography, which is installed at the beam-hole 08 of the 5 MW, IEA-R1 Nuclear Research Reactor. The most important modifications at the such facility were the increase of the ?-radiation filter thickness, increase of the inner area of the shielding, design of a neutron collimator and a light tight box. The main characteristics of the neutron beam at the irradiation position are: flux: 1 x 106n/cm2s, collimation ratio 70, effective energy 7 meV, diameter 20 cm, neutron/? ratio ? 106n/cm2mrem. The real-time images have been obtained by means of an imaging system that consists of a screen scintillator, a light intensifier, a video camera, a digitizing frame grabber and a computer. The device composed by the scintillator and by the light intensifier is called LIXI (Light Intensifier X-ray Image). Improvements concerning image quality have been obtained by means of digital processing. The facility has been characterized in terms of its sensitivity for thickness discerning (?x), and spatial resolution (Ut) and the obtained values were (?x = 0.07 cm (LuciteTM) and Ut = 440 ?m. These results were complemented by the modulation transfer function and, when compared with r function and, when compared with those from literature, they show that the present system's viability for inspection of both static and dynamic events. (author)

346

[Radiography of the thorax with phospholuminescent screens].  

Science.gov (United States)

Image digitalization can be performed in several ways: equalization of the x-ray beam (Scanning Equalization Radiography and Advanced Multiple-Beam Equalization Radiography), digital fluorography, use of linear computed tomography detectors, digitalization of radiographic films and memory screens. Phospholuminescent screens use an x-ray receptor which is able to store the x-ray energy. This latent energy is then extracted and can be processed to obtain images with matrices ranging between 1,760 x 2,140 and 1,770 x 2,370. Several types of image processing systems can be used depending on the pathology investigated. The blurred mask substraction method is the most widely used. The first clinical results demonstrate a reduction in patient irradiation and performances equal to or better than those of standard x-rays. PMID:8092748

Frija, J; Zagdanski, A M; De Kerviler, E; Attal, P; Laval-Jeantet, M

1994-01-01

347

An introduction to industrial radiography  

International Nuclear Information System (INIS)

The subject is discussed under the headings: definition and scope of technique; radiation sources; safety; selection of radiation source; photographic film; intensifying screens; film processing; radiographic sensitivity; contrast; unsharpness; scatter; image quality indicators; interpretation of radiographs; radiographic technique; radiography standards; real-time radiography; instantaneous image; permanent record; image enhancement; conclusions. (U.K.)

348

Evaluation of the effectiveness of digital radiography in emergency situations  

International Nuclear Information System (INIS)

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

349

Saferad industrial radiography system  

International Nuclear Information System (INIS)

The Saferad industrial radiography system is a system for execution of radiographic tests that provide small rays of insulation compared to conventional techniques. The system consists of a special irradiator that can be operated in three modes of exposure: Projection, Directional, and Panoramic with a set of collimators for different diameters of tubes, which collimate the radiation only to the area of the film. The radioisotope used is Selenium-75. Complements the system the shielding GammaBlok, polymer based on cadmium, flexible, non-toxic, and presented in various dimensions and shapes. It should involve the radiographic arrangement to shield the radiation after it goes through the film and the scattered radiation

350

Postextubation portable chest radiography  

International Nuclear Information System (INIS)

Portable chest radiography of recently extubated patients demonstrates radiographic worsening discordant with the patients' clinical improvement. This study was undertaken to characterize this previously unreported phenomenon. Twenty-seven patients had preextubation and postextubation radiographs reviewed blindly and graded for inspiration, atelectasis, infiltrates, effusions, and overall conditions. Projected lung areas were measured. A statistically significant majority of the films showed worsening of the patients' pulmonary status due to variable contributions of infiltrates and atelectasis, independent of inspiratory depth. This was felt to be due to subclinical pulmonary edema and atelectasis made manifest by the removal of positive-pressure ventilation

351

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

352

Computational methods for global/local analysis  

Science.gov (United States)

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

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

1992-01-01

353

Investigation of low-dose radiography for the lumbar spine using digital radiography system  

International Nuclear Information System (INIS)

Objective: To evaluate the low dose performance of digital radiography (DR) system for radiography of the lumbar spine. Methods: In the experiment CDRAD2.0 contrast-detail phantom was used for the evaluating the relation between the image qualities of both the computed radiography (CR) and digital radiography (DR) and the entrance surface dose (ESD). Thirty images of adult lumbar spine were radiographed by CR and DR separately, with ESD of DR being set at 1/3 of that of CR. Six radiologists reviewed the images obtained with both CR and DR, focusing on the details of bone trabecula of the first and second lumbar spine. Results: In separate reading of either CR or DR images by the two groups, the results showed no statistically significant difference between CR and DR (t=0.369, P>0.05). In cross- comparison reading, the results also showed no statically significant difference in the image details of bony trabecula between CR and DR (t=0.471, P>0.05). Conclusion: The superior resolution, low noise and high detective quantum efficiency (DQE)characteristics of DR can be utilized to decrease the radiation dosage, while not compromising the imaging quality. (authors)

354

A computerized scheme for lung nodule detection in multiprojection chest radiography  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: Our previous study indicated that multiprojection chest radiography could significantly improve radiologists’ performance for lung nodule detection in clinical practice. In this study, the authors further verify that multiprojection chest radiography can greatly improve the performance of a computer-aided diagnostic (CAD) scheme.

Guo, Wei; Li, Qiang; Boyce, Sarah J.; Mcadams, H. Page; Shiraishi, Junji; Doi, Kunio; Samei, Ehsan

2012-01-01

355

Radiographie evaluation of restaurations of endodontically treated teeth with individual post  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Timely und quality restauration of endodontically treated teeth is one of the major conditions for success of endodontic therapy. The aim of this study was to determine the efficiency of individual post cemented in endodontically treated teeth using radiographie parameters. 142 endodontically treated teeth restored with individual posts and permanent prosthetic restaurations were included in the clinical and radiographie research. The results of radiographie analysis reveled correctly made an...

Živkovi? Slavoljub; Jefi? Bojana; Mileti? Vesna J.; Lazi? Vojkan

2002-01-01

356

Proton radiography for clinical applications  

International Nuclear Information System (INIS)

Proton imaging is not yet applied as a clinical routine, although its advantages have been demonstrated. In the context of quality assurance in proton therapy, proton images can be used to verify the correct positioning of the patient and to control the range of protons. Proton computed tomography (pCT) is a 3D imaging method appropriate for planning and verification of proton radiation treatments, because it allows evaluating the distributions of proton stopping power within the tissues and can be directly utilized when the patient is in the actual treatment position. The aim of the PRoton IMAging experiment, supported by INFN, and the PRIN 2006 project, supported by MIUR, is to realize a proton computed radiography (pCR) prototype for reconstruction of proton images from a single projection in order to validate the technique with pre-clinical studies and, eventually, to conceive the configuration of a complete pCT system. A preliminary experiment performed at the 250 MeV proton synchrotron of Loma Linda University Medical Center (LLUMC) allowed acquisition of experimental data before the completion of PRIMA project's prototype. In this paper, the results of the LLUMC experiment are reported and the reconstruction of proton images of two phantoms is discussed.

357

Computational intelligent data analysis for sustainable development  

CERN Document Server

Going beyond performing simple analyses, researchers involved in the highly dynamic field of computational intelligent data analysis design algorithms that solve increasingly complex data problems in changing environments, including economic, environmental, and social data. Computational Intelligent Data Analysis for Sustainable Development presents novel methodologies for automatically processing these types of data to support rational decision making for sustainable development. Through numerous case studies and applications, it illustrates important data analysis methods, including mathemat

Yu, Ting; Simoff, Simeon

2013-01-01

358

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

International Nuclear Information System (INIS)

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

359

Dual energy scanning beam X-radiography  

Science.gov (United States)

Dual energy X-radiography is a method first developed in the mid-1970's by which one uses the information contained in the energy spectrum of the transmitted X-ray flux through an object. With this information one can distinguish the types of materials present in a radiograph and thus allow a computer to subtract them from the image enhancing the contrast of the remaining materials. Using this method, one can see details, which would have been hidden by overlying structures of other materials such as seen in radiographs of parts, made up of mixtures of metals and composites. There is also great interest in this technique for medical imaging of the chest where images of the organs are significantly improved by subtracting the bones. However, even with the enhanced capabilities realized with this technique, the majority of X-radiography systems only measures the bulk transmitted X-ray intensity and ignores the information contained in the energy spectrum. This is due to the added expense, time requirements, and registration problems incurred using standard radiographic methods to obtain dual energy radiographs. This dissertation describes a novel method which overcomes these problems and allows one to perform inexpensive, near real time, single shot dual energy X-radiography. The work of this thesis resulted in US patent #5,742,660.

Wojcik, Randolph Frank

360

Does applying the Canadian Cervical Spine rule reduce cervical spine radiography rates in alert patients with blunt trauma to the neck? A retrospective analysis  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background A cautious outlook towards neck injuries has been the norm to avoid missing cervical spine injuries. Consequently there has been an increased use of cervical spine radiography. The Canadian Cervical Spine rule was proposed to reduce unnecessary use of cervical spine radiography in alert and stable patients. Our aim was to see whether applying the Canadian Cervical Spine rule reduced the need for cervical spine radiography without missing significant cervical spine injuries. Methods This was a retrospective study conducted in 2 hospitals. 114 alert and stable patients who had cervical spine radiographs for suspected neck injuries were included in the study. Data on patient demographics, high risk & low risk factors as per the Canadian Cervical Spine rule and cervical spine radiography results were collected and analysed. Results 28 patients were included in the high risk category according to the Canadian Cervical Spine rule. 86 patients fell into the low risk category. If the Canadian Cervical Spine rule was applied, there would have been a significant reduction in cervical spine radiographs as 86/114 patients (75.4% would not have needed cervical spine radiograph. 2/114 patients who had significant cervical spine injuries would have been identified when the Canadian Cervical Spine rule was applied. Conclusion Applying the Canadian Cervical Spine rule for neck injuries in alert and stable patients would have reduced the use of cervical spine radiographs without missing out significant cervical spine injuries. This relates to reduction in radiation exposure to patients and health care costs.

Yesupalan Rajam

2008-06-01

 
 
 
 
361

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

362

Digital radiography: study of an alternative technique to conventional radiography  

International Nuclear Information System (INIS)

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

363

Computer-aided diagnosis in chest radiography: results of large-scale observer tests at the 1996-2001 RSNA scientific assemblies.  

Science.gov (United States)

Since 1996, computer-aided diagnosis (CAD) schemes have been presented as interactive demonstrations on computer workstations at each scientific assembly of the Radiological Society of North America. The schemes involved (a) detection of pulmonary nodules, (b) temporal subtraction, (c) detection of interstitial lung disease, (d) differential diagnosis of interstitial lung disease, and (e) distinction between benign and malignant pulmonary nodules on chest radiographs. Large-scale observer tests were carried out to examine how radiologists can benefit from CAD systems. Observer performance was evaluated by analysis of receiver operating characteristic (ROC) curves. The statistical significance of the difference between the areas under the ROC curves without and with CAD was analyzed with the Student t test. In all of the tests, the diagnostic accuracy of the radiologists in total improved significantly when CAD was used. This result provides additional evidence that CAD has the potential to improve the performance of radiologists in their decision-making process in interpreting chest radiographs. PMID:12533660

Abe, Hiroyuki; MacMahon, Heber; Engelmann, Roger; Li, Qiang; Shiraishi, Junji; Katsuragawa, Shigehiko; Aoyama, Masahito; Ishida, Takayuki; Ashizawa, Kazuto; Metz, Charles E; Doi, Kunio

2003-01-01

364

Direct digital radiography versus conventional radiography for estimation of canal length in curved canals  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study was to compare the conventional and digital radiography in the estimation of working length in mandibular molars. Sixty molar teeth were selected and divided into three groups in the basis of canal curves (0-15 degree, 15-30 degree, >30 degree). After the placement of a 15 K-file, radiographs were taken with a conventional film (F-speed) and a digital sensor. Canal lengths were measured in these images by two observers. Statistical analysis was performed with repeated measures of ANOVA and paired sample t-test with 95% confidence. There was a high inter-observer agreement on the measurements of working length in conventional and digital radiographs. There was no significant difference between the mean values of measurements in conventional and digital radiography. Moreover, there was no significant difference between conventional and digital radiography with the actual values in the basis of canal curves. The accuracy of conventional and digital radiography in the determination of the working length was in an acceptable range.

Mohtavipour, Seiedeh Tahereh; Dalili, Zahra; Azar, Nasim Gheshlaghi [Faculty of Dentistry, Guilan University of Medical Sciences, Guilan (Iran, Islamic Republic of)

2011-03-15

365

Direct digital radiography versus conventional radiography for estimation of canal length in curved canals  

International Nuclear Information System (INIS)

The purpose of this study was to compare the conventional and digital radiography in the estimation of working length in mandibular molars. Sixty molar teeth were selected and divided into three groups in the basis of canal curves (0-15 degree, 15-30 degree, >30 degree). After the placement of a 15 K-file, radiographs were taken with a conventional film (F-speed) and a digital sensor. Canal lengths were measured in these images by two observers. Statistical analysis was performed with repeated measures of ANOVA and paired sample t-test with 95% confidence. There was a high inter-observer agreement on the measurements of working length in conventional and digital radiographs. There was no significant difference between the mean values of measurements in conventional and digital radiography. Moreover, there was no significant difference between conventional and digital radiography with the actual values in the basis of canal curves. The accuracy of conventional and digital radiography in the determination of the working length was in an acceptable range.

366

Improvements relating to radiography  

International Nuclear Information System (INIS)

An improved combination of photosensitive materials suitable for use in radiography is described, with particular reference to a combination for an X-ray intensifying screen of the fluorescent type and a silver halide recorder. The intensifying material comprises a phosphor consisting wholly or mainly of a rare earth metal activated lanthanum oxyhalide, having more than half its spectral energy emission > 410 nm wavelength, more than half its visible light spectral energy emission in the range 400 to 500 nm, and its maximum energy emission peak in the range 400 to 450 nm. The phosphor should have a coverage of at least 200 to 800 g of the oxyhalide per sq. m. The screen material also contains a dye or pigment that absorbs light within the emission spectrum of the phosphor. The photosensitive recording material incorporates at least one silver halide emulsion layer. The combination should give a screen intensification factor of at least 20 to 40 kV. (U.K.)

367

Radiography geometry principle  

International Nuclear Information System (INIS)

If one object placed in the field under the sun, we can see the shadow of that object in two dimensional where that object was placed. Nevertheless, the sun cannot penetrate deeply so that it will produce the shadow with same object. This principal also same as radiography, however, with ionizing radiation, it can penetrate through the object so that the image that produced not only the shadow of the object but also what are inside the object. So this can give advantages for the radiographer to make inspection what are inside this object. The images that produce depend with the shape, density, thickness and distance between the object, film and source. The reader also will introduce with some term such as Distance source to film, distance source to object, and distance object to film also some basic on DIN standard and API 1104 Standard.

368

Impact analysis on a massively parallel computer  

International Nuclear Information System (INIS)

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

369

Annual Scientific Report 2004-2005 Proton Radiography: Cross Section Measurements and Detector Development  

Energy Technology Data Exchange (ETDEWEB)

Our research grant provides support for a program to measure forward production of neutrons and photons produced by high-energy proton beams striking a variety of targets. This will provide data essential to proton radiography. This work is carried out in conjunction with the Fermilab E-907 (MIPP) collaboration including physicists from Lawrence Livermore Laboratory. Our group is responsible for the E907 forward neutron/photon calorimeters. We are taking a leading role in obtaining and analyzing the forward production data and in helping to develop an optimal detector for proton radiography. With the support of our Stewardship Science Academic Alliances Grant DE-FG03-03NA00077, we were able to design, build, and commission the calorimeters on budget and ahead of schedule. E-907 officially started physics running at Fermilab in January 2005. We expect to continue data taking through October 2005. The analysis of the data, which we expect will be challenging because data from many different detector systems must be understood and merged, will take several years. Our group is in a unique position to complete the measurements, analyze the data, and help set up a database to be used by LLNL and LANL to make this information accessible for proton radiography. This work will be done in conjunction with the Livermore Laboratory High Energy Physics and Computational Nuclear Physics Groups. The project is meeting or exceeding its technical milestones, while remaining within its budget.

Michael J. Longo

2005-03-11

370

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

371

Computer Method for Amplitude Spectrum Analysis  

Directory of Open Access Journals (Sweden)

Full Text Available A computer programme based on Fortran IV language for doing Amplitude Spectrum Analysis (ASPEC and the associated flow charts are explained. The importance of the programme in the ionosphere and space research is briefly discussed.

P.C.S. Devara

2014-03-01

372

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

373

Computer Programming in a Spatial Analysis Course.  

Science.gov (United States)

Contends that students in spatial analysis courses generally are familiar with computer use and programs but lack basic computer programing skills. Describes four exercises in which students learn programing using BASIC and dBASE. Asserts that programming exercises help students clarify concepts, understand the rationale behind calculations, use…

Gesler, Wilbert; Kaplan, Abram

1993-01-01

374

Discourse Analysis of Teaching Computing Online  

Science.gov (United States)

This paper analyses the teaching and learning of computing in a Web-conferencing environment. A discourse analysis of three introductory programming learning episodes is presented to demonstrate issues and effects that arise when teaching computing using such an approach. The subject of discussion, the interactive nature of discussion and any…

Bower, Matt

2009-01-01

375

Euratom neutron radiography working group  

International Nuclear Information System (INIS)

In 1979 a Neutron Radiography Working Group (NRWG) was constituted within Euratom with the participation of all centers within the European Community at which neutron facilities were available. The main purpose of NRWG was to standardize methods and procedures used in neutron radiography of nuclear reactor fuel as well as establish standards for radiographic image quality of neutron radiographs. The NRWG meets once a year in each of the neutron radiography centers to review the progress made and draw plans for the future. Besides, ad-hoc sub-groups on different topics within the field of neutron radiography are constituted. This paper reviews the activities and achievements of the NRWG and its sub-groups. (author)

376

Filters used in scoliosis radiography  

International Nuclear Information System (INIS)

The use of X-ray filters during full spinal radiography for scoliosis in adolescent patients is discussed. The filters compensate for differences in body thickness while maintaining optimum image quality. They also help to reduce patient dose

377

Computational methods in power system analysis  

CERN Document Server

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

Idema, Reijer

2014-01-01

378

Computer simulation, nuclear techniques and surface analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article is about computer simulation and surface analysis by nuclear techniques, which are non-destructive. The “energy method of analysis” for nuclear reactions is used. Energy spectra are computer simulated and compared with experimental data, giving target composition and concentration profile information. Details of prediction stages are given for thick flat target yields. Predictions are made for non-flat targets having asymmetric triangular surface contours. The method is succe...

Reis, A. D.; Pacheco, C. F. F. P. R.; Pacheco Carvalho, J. A. R.

2010-01-01

379

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.)

380

Beam characterization at the Neutron Radiography Reactor  

Energy Technology Data Exchange (ETDEWEB)

Highlights: • The project characterized the beam at the Neutron Radiography Reactor. • Experiments indicate that the neutron energy spectrum model may not be accurate. • The facility is a category I radiography facility. • The beam divergence and effective collimation ratio are 0.3 ± 0.1° and >125. • The predicted total neutron flux at the image plane is 5.54 × 10{sup 6} n/cm{sup 2} s. -- Abstract: The quality of a neutron-imaging beam directly impacts the quality of radiographic images produced using that beam. Fully characterizing a neutron beam, including determination of the beam's effective length-to-diameter ratio, neutron flux profile, energy spectrum, potential image quality, and beam divergence, is vital for producing quality radiographic images. This paper provides a characterization of the east neutron imaging beamline at the Idaho National Laboratory Neutron Radiography Reactor (NRAD). The experiments which measured the beam's effective length-to-diameter ratio and potential image quality are based on American Society for Testing and Materials (ASTM) standards. An analysis of the image produced by a calibrated phantom measured the beam divergence. The energy spectrum measurements consist of a series of foil irradiations using a selection of activation foils, compared to the results produced by a Monte Carlo n-Particle (MCNP) model of the beamline. The NRAD has an effective collimation ratio greater than 125, a beam divergence of 0.3 ± 0.1°, and a gold foil cadmium ratio of 2.7. The flux profile has been quantified and the facility is an ASTM Category 1 radiographic facility. Based on bare and cadmium covered foil activation results, the neutron energy spectrum used in the current MCNP model of the radiography beamline over-samples the thermal region of the neutron energy spectrum.

Morgan, Sarah W. [Nuclear Science and Engineering Program, Colorado School of Mines, 1500 Illinois Street, Golden, CO 80401 (United States); King, Jeffrey C., E-mail: kingjc@mines.edu [Nuclear Science and Engineering Program, Colorado School of Mines, 1500 Illinois Street, Golden, CO 80401 (United States); Pope, Chad L. [Materials and Fuel Complex, Idaho National Laboratory, Scoville, ID 83415 (United States)

2013-12-15

 
 
 
 
381

Beam characterization at the Neutron Radiography Reactor  

International Nuclear Information System (INIS)

Highlights: • The project characterized the beam at the Neutron Radiography Reactor. • Experiments indicate that the neutron energy spectrum model may not be accurate. • The facility is a category I radiography facility. • The beam divergence and effective collimation ratio are 0.3 ± 0.1° and >125. • The predicted total neutron flux at the image plane is 5.54 × 106 n/cm2 s. -- Abstract: The quality of a neutron-imaging beam directly impacts the quality of radiographic images produced using that beam. Fully characterizing a neutron beam, including determination of the beam's effective length-to-diameter ratio, neutron flux profile, energy spectrum, potential image quality, and beam divergence, is vital for producing quality radiographic images. This paper provides a characterization of the east neutron imaging beamline at the Idaho National Laboratory Neutron Radiography Reactor (NRAD). The experiments which measured the beam's effective length-to-diameter ratio and potential image quality are based on American Society for Testing and Materials (ASTM) standards. An analysis of the image produced by a calibrated phantom measured the beam divergence. The energy spectrum measurements consist of a series of foil irradiations using a selection of activation foils, compared to the results produced by a Monte Carlo n-Particle (MCNP) model of the beamline. The NRAD has an effective collimation ratio greater than 125, a beam divergence of 0.3 ± 0.1°, and a gold foil cadmium ratio of 2.7. The flux profile has been quantified and the facility is an ASTM Category 1 radiographic facility. Based on bare and cadmium covered foil activation results, the neutron energy spectrum used in the current MCNP model of the radiography beamline over-samples the thermal region of the neutron energy spectrum

382

Supercomputing with Parallel Computers in Reactor Analysis  

International Nuclear Information System (INIS)

As many other scientific and engineering problems, reactor analysis is highly computing intensive. Accurate description of a reactor demands computers that are many orders of magnitude faster than today's top-level supercomputers. In the paper, parallel architecture rep-resenting the most feasible way of achieving desired computer performance is summarized. The paper also provides results of our experience in parallel computation on a transputer network: parallel solution of the neutron diffusion equation obtained using domain decomposition method, and parallel processing of the two-dimensional fuel assembly transport calculation and depletion calculation

383

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

International Nuclear Information System (INIS)

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

384

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

385

Image quality and exposure dose in digital projection radiography  

International Nuclear Information System (INIS)

Purpose: Comparison of the imaging capabilities of storage phosphor (computed) radiography and flat plate radiography with conventional film-screen radiography to find new strategies for quality and dose management, i.e., optimizing imaging quality and dose depending on the imaging method and clinical situation. Materials and Methods: Images of a CDRAD-phantom, hand-phantom, abdomen-phantom and chest-phantom obtained with different exposure voltages (50 kV, 73 kV, 109 kV) and different speeds (200, 400, 800, 1600) were processed with various digital systems (flat plate detector: Digital Diagnost [Philips]; storage phosphors: ADC-70 [Agfa], ADC-Solo [Agfa], FCR XG 1 [Fuji]) and a conventional film-screen system (HT100G/Ortho Regular [Agfa]). Results: The evaluation of CDRAD images found the flat plate detector system to have the highest contrast detectability for all dose levels, followed by the FCR XG 1, ADC-Solo and ADC-70 systems. Comparison of the organ-phantom images found the flat plate detector system to be equal to film-screen radiography and especially to storage phosphor systems even for low exposure doses. Conclusions: Flat plate radiography systems demonstrate the highest potential for high image quality when reducing the exposure dose. Depending on the system generation, the storage phosphor systems also show an improved image quality, but the possibility of a dose reduction is limited in comparison with the flat plate detector system. (orig.)late detector system. (orig.)

386

Radiation doses to patients undergoing scoliosis radiography.  

Science.gov (United States)

In this study we computed the radiation doses associated with scoliosis radiography and investigated how these radiation doses are influenced by the weight of the patient. We recorded the radiographic technique factors of 61 consecutive patients (46 females and 15 males) undergoing scoliosis radiography. A wedge-shaped aluminium filter attenuated the X-ray beam in the "chest region" relative to the "abdomen region". X-ray tube air kerma output factors (microGy mAs-1) and half value layers (HVLs) were determined experimentally for the "chest region" and "abdomen region". The energy imparted to each patient was computed from the air kerma area product, X-ray beam HVL and measured patient thickness. Values of patient effective dose were obtained using effective dose-to-energy conversion factors for specified radiographic projections, taking into account each patient's weight. The median patient age was 17 years, and the median patient weight was 53 kg. Entrance skin air kerma values in the "chest region" were approximately a factor of four lower than those in the "abdomen region". The air kerma values increased by a factor of two when the patient weight increased from 30 kg to 70 kg. Approximately 80% of the total energy imparted to a patient undergoing a scoliosis examination was in the "abdomen region", with the remaining 20% imparted to the "chest region". Energy imparted increased with patient weight, and was approximately 3 mJ for a 30 kg patient and approximately 8 mJ for a 70 kg adult patient. Effective doses showed little correlation with patient weight, with an average-sized patient (50 kg) receiving an effective dose of approximately 140 microSv. Patients undergoing scoliosis radiography receive effective doses that are low in comparison with other types of radiographic examination. PMID:11026860

Chamberlain, C C; Huda, W; Hojnowski, L S; Perkins, A; Scaramuzzino, A

2000-08-01

387

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

388

High speed motion neutron radiography of two-phase flow  

International Nuclear Information System (INIS)

Current research in the area of two-phase flow utilizes a wide variety of sensing devices, but some limitations exist on the information which can be obtained. Neutron radiography is a feasible alternative to ''see'' the two-phase flow. A system to perform neutron radiographic analysis of dynamic events which occur on the order of several milliseconds has been developed at Oregon State University. Two different methods have been used to radiograph the simulated two-phase flow. These are pulsed, or ''flash'' radiography, and high speed movie neutron radiography. The pulsed method serves as a ''snap-shot'' with an exposure time ranging from 10 to 20 milliseconds. In high speed movie radiography, a scintillator is used to convert neutrons into light which is enhanced by an optical intensifier and then photographed by a high speed camera. Both types of radiography utilize the pulsing capability of the OSU TRIGA reactor. The principle difficulty with this type of neutron radiography is the fogging of the image due to the large amount of scattering in the water. This difficulty can be overcome by using thin regions for the two-phase flow or using heavy water instead of light water. The results obtained in this paper demonstrate the feasibility of using neutron radiography to obtain data in two-phase flow situations. Both movies and flash radiographs have been obtained of air bubbles in water and boiling from a heater element. The neutron radiographs of the boiling element sutron radiographs of the boiling element show both nucleate boiling and film boiling. (Auth.)

389

Heavy-ion radiography  

International Nuclear Information System (INIS)

High energy, heavy-ion beams offer superior discrimination of tissue electron densities at very low radiation doses. This characteristic has potential for diagnostic medical imaging of neoplasms arising in the soft tissues and organs because it can detect smaller inhomogeneities than x rays. Heavy-ion imaging may also increase the accuracy of cancer radiotherapy planning involving use of accelerated charged particles. In the current physics research program of passive heavy-ion imaging, critical modulation transfer function tests are being carried out in heavy-ion projection radiography and heavy-ion computerized tomography. The research goal is to improve the heavy-ion imaging method until it reaches the limits of its theoretical resolution defined by range straggling, multiple scattering, and other factors involved in the beam quality characteristics. Clinical uses of the imaging method include the application of heavy-ion computerized tomography to heavy-ion radiotherapy planning, to the study of brain tumors and other structures of the head, and to low-dose heavy-ion projection mammography, particularly for women with dense breasts where other methods of diagnosis fail. The ions used are primarily 300 to 570 MeV/amu carbon and neon ions accelerated at the Lawrence Berkeley Laboratory Bevalac

390

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

391

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

Science.gov (United States)

With the goal of achieving real time and efficient edge extraction for digital radiography, an accelerated H-LBP-based edge extraction method (AH-LBP) is presented in this paper by improving the existing framework of local binary pattern with the H function (H-LBP). Since the proposed method avoids computationally expensive operations with no loss of quality, it possesses much lower computational complexity than H-LBP. Experimental results on real radiographies show desirable performance of our method.

Qiao, Shuang; Zhao, Chen-yi; Huang, Ji-peng; Sun, Jia-ning

2015-01-01

392

[Fabrication of improved multi-slit equipment to obtain the input-output characteristics of computed radiography systems: correction of the heel effect, and application to high tube-voltage experiments].  

Science.gov (United States)

Multi-slit equipment is a new experimental apparatus that can measure the input-output characteristics of a CR (computed radiography) system with limited influence of the fading effect. Kimoto et al. recently proposed a new type of multi-slit apparatus in which the multi-slit setup, the insertion region of the phosphor plate, and plate shielding are integrated to create a single handy-type item (an all-in-one type multi-slit apparatus). However, some problems remained unsolved. The aims of this study were to devise a setup for application to high tube voltage conditions, and to improve the all-in-one type multi-slit equipment so as to correct the heel effect. We examined the capabilities of our improved multi-slit equipment using diagnostic X-ray apparatus and found that it can obtain input-output characteristics with 5% accuracy for tube voltages of 40-140 kV and SID (source to image receptor distances) of 50-200 cm. PMID:25242595

Maehata, Itsumi; Hayashi, Hiroaki; Takegami, Kazuki; Ujita, Syohei; Kimoto, Natsumi; Konishi, Yuki; Fukuda, Ikuma

2014-09-01

393

Avaliação da tomografia de alta resolução versus radiografia de tórax na doença intersticial pulmonar na esclerose sistêmica High-resolution computed tomography versus chest radiography in the diagnosis of interstitial lung disease in systemic sclerosis  

Directory of Open Access Journals (Sweden)

Full Text Available OBJETIVO: Avaliar a acurácia da tomografia de alta resolução (TCAR do tórax em relação à radiografia simples (RX do tórax no diagnóstico de doença intersticial pulmonar relacionada à esclerose sistêmica (ES. MATERIAIS E MÉTODOS: Foram realizados TCAR e RX de tórax em póstero-anterior e perfil em 34 pacientes com diagnóstico de ES, segundo critérios do Colégio Americano de Reumatologia, e feita comparação entre as prevalências dos achados radiológicos sugestivos de doença intersticial pulmonar encontradas com estes dois métodos de imagem. RESULTADOS: Foram observadas alterações em 31 (91% das TCAR, enquanto 16 (47% dos RX de tórax se apresentavam alterados. Os achados mais freqüentes à TCAR foram: linhas septais (74%, faveolamento (56% e bandas parenquimatosas (26%, localizados predominantemente nas bases pulmonares. Os RX de tórax demonstraram áreas de infiltrado reticular em 32% dos casos e distorção parenquimatosa em 12% dos pacientes. Em 18 (53% pacientes com RX de tórax normal a TCAR revelou espessamento septal em 55%, vidro fosco em 44%, faveolamento em 38,5% e cistos em 33%. CONCLUSÃO: A TCAR é mais sensível que o RX de tórax para a investigação de envolvimento intersticial pulmonar inicial em pacientes com ES, justificando, em casos incipientes, tratamento com terapia imunossupressora.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.

Ana Beatriz Cordeiro de Azevedo

2005-04-01

394

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

395

Using computers to teach behavior analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

When it is impractical to provide behavior analysis students with extensive laboratory experience using real organisms, computers can provide effective demonstrations, simulations, and experiments. Furthermore, such computer programs can establish contingency-shaped behavior even in lecture classes, which usually are limited to establishing rule-governed behavior. We describe the development of computerized shaping simulations and the development of software that teaches students to discrimin...

Shimoff, Eliot; Catania, A. Charles

1995-01-01

396

Digital Radiography in Kenya today  

International Nuclear Information System (INIS)

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

397

Comparación de la radiografía simple y la tomografía computarizada en el diagnóstico de hernia discal tipo 1 en perros / Comparison of plain radiography and computed tomography in the diagnosis of type 1 disc herniation in dogs  

Scientific Electronic Library Online (English)

Full Text Available SciELO Peru | Language: Spanish Abstract in spanish Los objetivos del estudio fueron describir los hallazgos radiológicos de la radiografía simple en animales con sospecha de hernia discal y establecer su coincidencia con aquellos del examen tomográfico. Se estudiaron 16 pacientes caninos cuya evaluación neurológica reveló una disfunción neurológica [...] compatible a una compresión medular toracolumbar y una magnitud de lesión de grado III o superior. Dos pacientes no presentaron sospecha de diagnóstico de hernia discal en las dos pruebas y fueron retirados. La radiografía simple identificó 14 animales con signos radiográficos compatibles a una hernia discal. De estos, el 71.4% (10/14) de los resultados de los exámenes radiográficos y tomográficos fueron coincidentes en el diagnóstico de la enfermedad y la localización del espacio intervertebral afectado. Los signos radiográficos más frecuentes en los animales sospechosos a hernia discal tipo 1 por radiografía simple fueron la disminución del espacio intervertebral (13/14), disminución del foramen intervertebral (8/14) y opacidad del foramen intervertebral (4/14). Los hallazgos tomográficos de mayor presentación en los animales con hernia discal tipo 1 fueron la presencia de material discal en el canal medular (12/12), estenosis del canal medular (12/12) y la estenosis del espacio foraminal (8/12). El espacio intervertebral más afectado del segmento toracolumbar fue el L1-L2 (4/12). Se concluye que la radiografía simple no puede ser considerada como indicativo absoluto en el diagnóstico de hernia discal tipo 1 y, por lo tanto, es necesario complementar el diagnóstico con un examen tomográfico. Abstract in english The objectives of the study were to describe the radiologic findings of plain radiography in animals with suspected herniated disc and to establish coincidences with the computed tomography (CT) examination. Sixteen dogs were studied, whose neurological evaluation revealed a neurological dysfunction [...] compatible with thoracolumbar spinal cord compression and a magnitude of injury of grade III or higher. Two patients failed to show signs of disc herniation in both tests and were withdrawn from the study. Plain radiographies identified 14 animals with radiographic abnormalities consistent with a herniated disc. In 71.4% (10/14) of these cases, the results between radiographic and CT examinations coincided in the diagnosis of the presence of the disease and location of the affected intervertebral space. The radiographic findings most common in animals suspected to herniated disc type 1 were narrowed intervertebral space (13/14), decreased size intervertebral foramen (8/14) and opacity of the intervertebral foramen (4/14). The most common CT findings in animals with herniated disc type 1 were the presence of disc material in the spinal canal (12/12), spinal canal stenosis (12/12), and the foraminal space stenosis (8/12). The intervertebral space most affected thoracolumbar segment was the L1-L2 (4/12). The results show that plain radiography cannot be regarded as an absolute indicator in the diagnosis of type 1 disc herniation, and it should be complemented with a CT examination.

Rosmery, Donaires V; Diego, Díaz C; Ysaac, Chipayo G; César, Gavidia C.

398

Digital radiography in urography  

International Nuclear Information System (INIS)

The clinical utility was evaluated of a computed radiographic system in urography. The system (FCR101, Philips Medical Systems, Inc., Shelton, CT) is based on a photostimulable phosphor screen (imaging plate) for X-ray image detection and storage. The X-ray information recorded on the imaging plate is converted into digital form and processed by means of a computer. After processing is completed, the digitized image is reversed back to analogic signals, which modulate the intensity of a laser beam scanning the image on a sigle-emulsion film (Fuji CR 633). Two hundred ivp's were obtained in four groups, of 50 patients each, with normal azotemic values by rapid infusion of a low osmolatility contrast medium (Iopamidol 150 mgI/ml). While conventional radiographs were performed on the first group of patients with the injection of 0.6 gl/Kg body weight of contrast medium, digital examinations were carried out, in the remaining three groups, with the injection of 0.6, 0.3 and 0.12 gl/Kg, respectively. The digital images were processed with the '' Abdomen-routine'' program. A specific algorithm was implemented in order to reduce the excessive contrast resolution of the bladder, which is due to the characteristics of the nonionic contrast medium and enhanced by the reading program. The image details were evaluated by two observers and then statistically analyzed with non-parametric test. Statistical analysis did not show any difference in the quality of digital and screen-file in the quality of digital and screen-film images. Image processing improved some inadequate images, by reducing the contrast resolution of the bladder, and allowed a better detection of some details. Low doses (0.3 gl/Kg) of a low osmolality (150 mgl/Kg) contrast medium were enough to obtain good images. Another biological advantage was obtained by a consistent radiation dose reduction (about 40%)

399

Use of fluorescent screens for isotope radiography  

International Nuclear Information System (INIS)

Radiographic examination can be performed on items beyond the limitation of conventional isotope radiography without a great loss of resolution. With proper film and screen selection and scatter radiation control, fluorescent screens can be a valuable additional tool for radiography

400

HL-20 computational fluid dynamics analysis  

Science.gov (United States)

The essential elements of a computational fluid dynamics analysis of the HL-20/personnel launch system aerothermal environment at hypersonic speeds including surface definition, grid generation, solution techniques, and visual representation of results are presented. Examples of solution technique validation through comparison with data from ground-based facilities are presented, along with results from computations at flight conditions. Computations at flight points indicate that real-gas effects have little or no effect on vehicle aerodynamics and, at these conditions, results from approximate techniques for determining surface heating are comparable with those obtained from Navier-Stokes solutions.

Weilmuenster, K. J.; Greene, Francis A.

1993-01-01

 
 
 
 
401

Image quality in radiography of midfacial trauma  

Energy Technology Data Exchange (ETDEWEB)

Image quality in radiography of midfacial trauma was studied in 618 patients treated for midfacial injury. The visibility of key anatomic areas was related to essential technical factors influencing image quality as well as to the radiologic diagnostic performance. Regression analysis revealed that the visibility of the key anatomic areas was significantly dependent on the technical factors. However, the radiologic diagnostic performance was not significantly dependent on the visibility of the key anatomic areas. The results indicate that image quality was not a limiting factor for radiologic diagnostic performance in midfacial trauma.

Kinnunen, J.