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1

Computational radiology in skeletal radiography  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2009-11-15

2

Computational radiology in skeletal radiography.  

Science.gov (United States)

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. PMID:19581060

Peloschek, Ph; Nemec, S; Widhalm, P; Donner, R; Birngruber, E; Thodberg, H H; Kainberger, F; Langs, G

2009-11-01

3

Pediatric musculoskeletal computed radiography  

International Nuclear Information System (INIS)

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

1997-07-01

4

Pediatric musculoskeletal computed radiography  

Energy Technology Data Exchange (ETDEWEB)

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

Kottamasu, S.R. [Department of Pediatric Imaging, Children`s Hospital of Michigan, 3901 Beaubien Boulevard, Detroit, MI 48201-2196 (United States); Kuhns, L.R. [Department of Pediatric Radiology, C. S. Mott Children`s Hospital, Ann Arbor, Michigan (United States); Stringer, D.A. [Department of Radiology, British Columbia`s Children`s Hospital, Vancouver, British Columbia (Canada)

1997-07-01

5

Differentiation of benign from malignant pulmonary nodules with the digital analysis of computed radiography  

International Nuclear Information System (INIS)

To differentiate benign pulmonary nodules from malignant nodules, digital analysis of computed radiography (CR) was performed retrospectively. A total of 142 histologically or clinically proved cases were studied. Digital analysis was performed using the method of gradient processing reported by Sherrier et al. Gradient number with and without background trend correction and gradient number corrected by L-value were obtained from the raw data of CR. The mean gradient of 93 malignant nodules was significantly different from that of 49 benign nodules. The analysis of gradient number without background trend correction and L-value correction was most sensitive. Seven radiologists evaluated these nodules as to benign or malignant, status, degree of calcification and homogeneity. A correlation was found between the detectability of benign nodules and degree of calcification. In conclusion, CR-gradient analysis is useful as a screening test to differentiate benign nodules from malignant ones. (author)

1993-10-01

6

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

International Nuclear Information System (INIS)

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

2007-04-13

7

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

International Nuclear Information System (INIS)

Osteoporosis is a disease that results in an increased risk of bone fracture due to a loss of bone mass and deterioration of bone structure. Bone mineral density (BMD) provides a measure of bone mass and is frequently measured by bone densitometry systems to diagnose osteoporosis. In addition, computerized radiographic texture analysis (RTA) is currently being investigated as a measure of bone structure and as an additional diagnostic predictor of osteoporosis. In this study, we assessed the ability of a peripheral bone densitometry (PD) system to yield images useful for RTA. The benefit of such a system is that it measures BMD by dual-energy x-ray absorptiometry and therefore provides high- and low-energy digital radiographic images. The bone densitometry system investigated was the GE/Lunar PIXI, which provides 512x512 digital images of the heel or forearm (0.2 mm pixels). We compared texture features of heel images obtained with this PD system to those obtained on a Fuji computed radiography (CR) system (0.1 mm pixels). Fourier and fractal-based texture features of images from 24 subjects who had both CR and BMD exams were calculated, and correlation between the two systems was analyzed. Fourier-based texture features characterize the magnitude, frequency content, and orientation of the trabecular bone pattern. Good correlation was found between the two modalities for the first moment (FMP) with r=0.71 (p value0.05), while the standard deviation of the RMS did correlate with r=0.79 (p value<0.0001). Good correlation was also found between the two modalities for the fractal-based texture features with r=0.79 (p value<0.0001) for the global Minkowski dimension and r=0.63 (p value=0.0007) for the fractal dimension from a box counting method. The PD system therefore may have the potential for yielding heel images suitable for RTA

2004-04-01

8

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

International Nuclear Information System (INIS)

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

2005-12-01

9

DATA compression for chest radiography and mammography using computed radiography  

International Nuclear Information System (INIS)

We have evaluated the degradation of image quality by irreversible data compression in computed radiography (CR). Analysis of the receiver operating characteristics (ROC) curves were made from the images reconstructed with reversible data and two types of irreversible compression data. With acryl beads (2 mm?) on the phantom simulating chest, the detectability as regards the images with irreversible compression was lower than that with reversible data. With film disk (5 mm?, 0.9 mm thickness), there was no difference between the detectability for both images. In clinical cases of chest radiography, ROC for pneumothorax, pulmonary nodules and reticulonodular opacities regards chest radiographs in newborns, infants and adults revealed no significant difference as regards the images, with reversible data and irreversible compression. With film disk (10 mm?, 0.1 mm thickness) regarding the phantom simulating breast, there was no images with a difference in detectability. With glass beads (0.2 mm?), irreversible compression was inferior to that with reversible data. In clinical cases of mammography, images with irreversible compression were greatly inferior regarding the visibility of calcification smaller than 0.25 mm. (author)

1995-01-01

10

DATA compression for chest radiography and mammography using computed radiography  

Energy Technology Data Exchange (ETDEWEB)

We have evaluated the degradation of image quality by irreversible data compression in computed radiography (CR). Analysis of the receiver operating characteristics (ROC) curves were made from the images reconstructed with reversible data and two types of irreversible compression data. With acryl beads (2 mm{phi}) on the phantom simulating chest, the detectability as regards the images with irreversible compression was lower than that with reversible data. With film disk (5 mm{phi}, 0.9 mm thickness), there was no difference between the detectability for both images. In clinical cases of chest radiography, ROC for pneumothorax, pulmonary nodules and reticulonodular opacities regards chest radiographs in newborns, infants and adults revealed no significant difference as regards the images, with reversible data and irreversible compression. With film disk (10 mm{phi}, 0.1 mm thickness) regarding the phantom simulating breast, there was no images with a difference in detectability. With glass beads (0.2 mm{phi}), irreversible compression was inferior to that with reversible data. In clinical cases of mammography, images with irreversible compression were greatly inferior regarding the visibility of calcification smaller than 0.25 mm. (author).

Murakami, Seiichi; Oda, Nobuhiro; Terata, Kunihiro; Kawashita, Yukitaka; Ueno, Yukako; Nakano, Hideichirou; Mori, Tomoko; Nakata, Hajime [Univ. of Occupational and Environmental Health, Kitakyushu (Japan). Hospital

1995-01-01

11

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

Science.gov (United States)

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

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

1994-05-01

12

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

2005-11-01

13

Computed radiography- the state of the art  

International Nuclear Information System (INIS)

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

2007-10-05

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)

2013-01-01

15

Bronchiectasis : diagnostic accuracy of chest computed radiography  

International Nuclear Information System (INIS)

The aim of this study was to assess the diagnostic accuracy of chest computed radiography for the detection of bronchiectasis diagnosed by high-resolution CT. Our study included 100 consecutive patients with bronchiectasis and 20 normal subjects, all seen on high-resolution CT. Two independent observers analyzed chest computed radiographs and recorded the presence and type of bronchiectasis, and the involved lobe. On high-resolution CT, bronchiectasis was seen in one lobe in 29 patients, two lobes in 29, three lobes in 16, four lobes in 14, five lobes in 10, and six lobes in two. The bronchiectasis was tubular in 55 patients, mixed tubular and cystic in 29, and cystic in 16. For observer 1, the sensitivity, specificity, and accuracy of chest computed radiography was 95%, 85%, and 93%, respectively, while for observer 2, the corresponding figures were 93%, 85%, and 92%. Sensitivity and specificity for observer 1 were 33% and 96% for the right upper lobe (46% and 95% for observer 2), 68% and 86% for the right middle lobe (76% and 86%), 70% and 78% for the right lower lobe (48% and 83%), 50% and 100% for the left upper lobe (50% and 97%), 63% and 90% for the lingular segment (49% and 93%), and 87% and 75% for the left lower lobe (75% and 90%), respectively. Tubular bronchiectasis involving a single lobe was the most common source of false negative readings based on the findings of chest computed radiography. Because chest computed radiography is not inferior to high-resolution CT for the detection of bronchiectasis, the routine use of chest computed radiography in screening for bronchiectasis is feasible. However, due to its low sensitivity in detecting bronchiectasis in a specific lobe, preoperative high-resolution CT examination may be needed

1999-05-01

16

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 "1"2"5I 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 "1"2"5I absorptiometry (r=0.82-0.94). (author)

1985-01-01

17

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

1998-05-19

18

FCR (Fuji Computed Radiography) in neurosurgery  

Energy Technology Data Exchange (ETDEWEB)

As part of the evolution of computer technology, Fuji Computed Radiography (FCR) has been developed as a new system for radiographical diagnosis. In this system, the X-ray energy is stored on the imaging plate and then converted into digital signals utilizing scanning laser-stimulated luminence. After proper image processing, it offers much more improved information for diagnosis than the conventional film system does. Since April, 1986, we have principally used FCR (System 101) for neurosurgical practice. In this article, we present our recent experience and evaluate its usefulness.

Hayashi, Akimune; Kyuma, Yoshikazu

1988-08-01

19

FCR (Fuji Computed Radiography) in neurosurgery  

International Nuclear Information System (INIS)

As part of the evolution of computer technology, Fuji Computed Radiography (FCR) has been developed as a new system for radiographical diagnosis. In this system, the X-ray energy is stored on the imaging plate and then converted into digital signals utilizing scanning laser-stimulated luminence. After proper image processing, it offers much more improved information for diagnosis than the conventional film system does. Since April, 1986, we have principally used FCR (System 101) for neurosurgical practice. In this article, we present our recent experience and evaluate its usefulness. (author)

1988-01-01

20

Phosphors for conventional and computed radiography  

International Nuclear Information System (INIS)

In medical radiography a combination of intensifying luminescent screens with a film is used commonly as a radiation receiver. Recently, a new method has been created which is frequently referred to as digital luminescent radiography (DLR) or computed radiography. This method is based on the application of screens storing energy of ionizing radiation and releasing it in the form of photo-stimulated luminescence (PSL) as they are scanned by a He-Ne laser beam. Such screens perform the function both of an X-ray converter, and that of the storage unit of the system. It is obvious that phosphors fabricated for intensifying screens and for image storing screens need to meet conflicting requirements. Nevertheless, a systematic investigation of phosphors for conventional screens has enabled phosphors with effective PSL as well as the conditions for their preparation to be found. In this paper special attention is devoted to the BaFBr:Eu phosphor - to the nature and distribution of defects in it and to the mechanism of its photo-stimulated luminescence. The important role of defect segregation, of anti-structural disordering of Frenkel type and of the diffusional mechanism of electron migration involving trapping is noted. (author)

1993-01-01

 
 
 
 
21

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)

2010-05-01

22

Optimization of Dose and Image Quality for Computed Radiography and Digital Radiography  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The surface doses to patients during chest, abdomen and pelvis radiography were measured over a period of 3 years, during which time computed radiography (CR) and digital radiography (DR) systems were introduced to replace film–screen systems. For film–screen and CR the surface doses were measured with thermoluminescent dosimeters. For DR the surface doses were calculated from the dose–area product (DAP) meter readings. Measurements were made for each type of examination and detector ty...

2006-01-01

23

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.)

1993-09-01

24

Computed radiography simulation using the Monte Carlo code MCNPX  

International Nuclear Information System (INIS)

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

2009-10-02

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)

2009-01-01

26

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

27

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

28

Performance evaluation of a computed radiography system  

Energy Technology Data Exchange (ETDEWEB)

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

Roussilhe, J.; Fallet, E. [Carestream Health France, 71 - Chalon/Saone (France); Mango, St.A. [Carestream Health, Inc. Rochester, New York (United States)

2007-07-01

29

Performance evaluation of computed radiography systems  

International Nuclear Information System (INIS)

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

2001-03-01

30

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

31

Some malpractices in application of computed radiography  

International Nuclear Information System (INIS)

Objective: To improve the CR image quality and to promote the digital image standard constitution by analyzing the common problems and malpractices in application of computed radiography. Methods: Phenomenon and reasons of 107 CR junk-films from nine three-'A'-hospitals were analyzed, discussed, recorded, and statistised by 20 radiologists, radiographers and engineers. Results: Among 107 junk films, there are 36 cases (33.64%) of incorrect operations, 29 cases (27.10%) of artifacts in reading and transferring the data of IP, 15 cases (14.02%) of artifacts in IP system, and 13 cases (12.15%) of selection of inappropriate radiographic parameters, and 9 cases (8.41%) of printer-failures, and 5 cases (4.67%) of inappropriate post-processing techniques. By analyzing the reasons of 107 junk films we found that 60.74% were due to less responsibilities and incorrect operations, and 35.51% were due to new problems in CR techniques, and other were due to inappropriate post-processing techniques. Conclusion: Responsibilities, operation regulations, digital image quality standards, studying of new techniques and appropriate use of the post-processing techniques are the key points for improving the CR image quality and the diagnosis level. (authors)

2007-02-01

32

Image analysis in industrial radiography  

International Nuclear Information System (INIS)

Non-destructive testing in nuclear power plants remains a major EDF objective for the coming decades. To facilitate diagnosis, the expert must be provided with elaborate decision-making aids: contrasted images, noise-free signals, pertinent parameters, ''meaningful'' images. In the field of industrial radiography, the inspector's offer of a portable system for digitalization and subsequent processing of radiographs (ENTRAIGUES) is an improvement in the inspection of primary circuit nozzles. Three major directions were followed: - improvement of images and localization of flaws (2D approach); techniques such as Markov modelling were evaluated and tested, - development of a system which can be transported on site, for digitalization, processing and subsequent archiving on inspection radiographs, known as ENTRAIGUES, - development of a program for aid in analysis of digitized radiographs (''bread-board'' version), offering an ergonomic interface and push-button processing, which is the software component in ENTRAIGUES and uses sophisticated methods: contrast enhancement, background flattening, segmentation. An other objective is to reconstruct a three-dimensional volume on the basis of a few radiographs taken at different incidences and to estimate the flaw orientation within a piece understudy. This information makes sense to experts, with regards to the deterioration rate of the flaw; the equipment concerned includes the formed bends in the primary coolant nozzles. This reconstruction problem is ill-posed and a solution can be obtained by introducing a priori information on the solution. The first step of our algorithm is a classical iterative reconstruction A.R.T. type method (Algebraic Reconstruction Techniques) which provides a rough volumic reconstructed tridimensional zone containing the flaw. Then, on this reconstructed zone, we apply a Bayesian restoration method introducing a Markov Random Field (MRF) modelling. Conclusive results have been obtained. (author). 2 figs., 4 refs

1993-01-01

33

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)

1990-01-01

34

Pilot study of bovine interdigital cassetteless computed radiography.  

Science.gov (United States)

Twenty-one limbs of bovine cadavers (42 digits) were exposed to interdigital cassetteless imaging plate using computed radiography. The radiographic findings included exostosis, a rough planta surface, osteolysis of the apex of the distal phalanx and widening of the laminar zone between the distal phalanx and the hoof wall. All these findings were confirmed by computed tomography. The hindlimbs (19 digits) showed more changes than the forelimbs (10 digits), particularly in the lateral distal phalanx. The cassetteless computed radiography technique is expected to be an easily applicable method for the distal phalanx rather than a conventional cassette-plate and/or the film-screen cassetteless methods. PMID:23782542

El-Shafaey, El-Sayed Ahmed Awad; Aoki, Takahiro; Ishii, Mitsuo; Yamada, Kazutaka

2013-11-01

35

Quantitative double-label radiography of two-dimensional protein gels using color negative film and computer analysis.  

Science.gov (United States)

We have devised a method of data collection and computer analysis which allows utilization of the resolving power of two-dimensional gel electrophoresis of proteins, in conjunction with the versatility of using two different radionuclides simultaneously. Cultures of Escherichia coli growing with exponential growth rate constants (mu) of 0.32 and 1.43 were labeled with [3H]leucine and [14C]leucine, respectively; these samples were mixed, and cell protein was separated on a two-dimensional gel. Spacial and quantitative data for both radionuclides were recorded on color negative film by radiographic exposure. Data for 14C alone were then collected photographically from the red-light-sensitive layer of the film using a red filter, while data for 3H and spillover of 14C were collected photographically from the blue-light-sensitive layer using a blue filter. These two data sets were analyzed by CINT, a computer program for analysis of two-dimensional gels, and quantitative data for 3H were calculated after determination of spillover of 14C in a manner analogous to quantification of 3H and 14C by liquid scintillation counting. Quantitative data from over 1000 protein spots representing from 0.002% to 10% of the total 3H or 14C, respectively, are available in a matter of hours. We have used this method to analyze the effect of growth rate and medium composition on the relative levels of individual proteins in a pathogenic strain of E. coli which contains group 111 O-antigen. As expected, the relative levels of aminoacyl-tRNA synthetases, protein chain elongation factors, ribosomal proteins, and the alpha-subunit of RNA polymerase are all increased with increased growth rate; the magnitude of these changes agreed with previous data derived using other strains of E. coli. Alterations in the levels of other proteins identified on the two-dimensional gels could be interpreted in terms of changes in medium composition. When compared to manual data collection by excising radiolabeled proteins and quantifying 3H and 14C in a liquid scintillation counter following combustion to H2O and CO2, respectively, this new method of data collection and computer analysis increases the resolution of data collection and decreases the time involved from days to hours. PMID:6341053

Goldman, R C; Trus, B L; Leive, L

1983-04-01

36

Computed radiography in X-ray examination of stomach. Evaluation by phantom experiments and clinical studies  

International Nuclear Information System (INIS)

The usefulness and clinical applicability of computed radiography(FCR) in X-ray examination of the stomach were evaluated in comparison with film-screen (FS) radiography by both phantom experiments and clinical studies. Receiver operating characteristic (ROC) curve analysis consisting of 25 normal and 25 artificially created simulated lesions on an orginally created Styrofoam phantom showed no difference in lesion detectability between FCR and FS radiography. Both were also equal in evaluation of the internal structure and margin of the 25 lesions by visual ranking. ROC curve analysis of clinical cases was performed in 30 cases, 20 normal and 10 abnormal, while evaluation by visual ranking was performed on 18 lesions. There was no significant difference between FCR and FS radiography either with ROC curve analysis or visual ranking, although the variations were somewhat greater in the clinical cases than in the phantom studies. I conclude that FCR is equal to FS radiography in X-ray examination of the stomach regarding both the detectability and visual conspicuity of the lesion. In view of the other advantages of FCR, it can safely replace conventional FS radiography in X-ray examination of the stomach. (author)

1995-08-01

37

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

2001-12-01

38

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-04-15

39

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

International Nuclear Information System (INIS)

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

2006-01-01

40

Computed radiography dose optimization in pediatric patients  

International Nuclear Information System (INIS)

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

2010-05-01

 
 
 
 
41

Studies on the Fuji computed radiography depended on the panoramic radiography  

International Nuclear Information System (INIS)

The Fuji Computed Radiography (FCR) developed recently involves the following procedures; photography in the same way as the hitherto radiography, printing auto imaging plate of photostimulable phospher, conversion to electric signals, and recording reproduced images by computerization. Highly valuable images for diagnoses in the medical field have already been obtained by the FCR. Then, we attempted to study FCR images panoramically radiographed for jaw lesions in the field of oral surgery. Method for study: As the samples to be studied, the selected subjects were cases of periodontal diseases, fracture of the jaw, odontogenic cyst and tumor, etc. In the present study the FCR images of panoramic radiography were compared with hitherto panoramic flat radiograms. Result of study: Although the images of the FCR vary depending on the methods of treatment, that is, on how gradient processing and spatial frequency enhancement are, the method of purpose-fitting treatment provided diagnostically significant images for grasping bone lesions. The images obtained from this FCR permitted us to grasp more distinctly condition of alveolar bone resorption in periodontal diseases, running of minute fracture lines in fracture of the jaw, and characteristic images of bone resorption in odontogenic cysts and tumor, etc. Thus the images of the FCR are highly useful in diagnosing bone lesions, but granularity of the images themselves have still been questioned, and additionally the images vary depending on the methods of gradient processing and spatial frequency enhancement. Therefore further repeat studies are probably needed for these questions. (author)

1986-01-01

42

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1993-09-01

43

Recognition and Prevention of Computed Radiography Image Artifacts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Initiated by complaints of image artifacts, a thorough visual and radiographic investigation of 197 Fuji, 35 Agfa, and 37 Kodak computed radiography (CR) cassettes with imaging plates (IPs) in clinical use at four radiology departments was performed. The investigation revealed that the physical deterioration of the cassettes and IPs was more extensive than previously believed. It appeared that many of the image artifacts were the direct result of premature wear of the cassettes and imaging pl...

Hammerstrom, Kevin; Aldrich, John; Alves, Len; Ho, Andrew

2006-01-01

44

Optimising the Use of Computed Radiography in Pediatric Chest Imaging  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective of this study was to analyze image quality of chest examinations in pediatric patients using computed radiography (CR) obtained with a wide range of doses to suggest the appropriate parameters for optimal image quality. A sample of 240 chest images in four age ranges was randomly selected from the examinations performed during 2004. Images were obtained using a CR system and were evaluated independently by three radiologists. Each image was scored using criteria proposed by the ...

Sanchez Jacob, R.; Vano-galvan, E.; Vano, E.; Gomez Ruiz, N.; Fernandez Soto, J. M.; Martinez Barrio, D.; Prieto, C.

2009-01-01

45

Computer-aided recognition of emphysema on digital chest radiography  

International Nuclear Information System (INIS)

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

2011-11-01

46

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

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.

48

Fuji computed radiography (FCR) for the diagnosis of spinal disorders  

International Nuclear Information System (INIS)

Since April, 1985, we have, in co-operation with the Fuji Film Co., Ltd., used Fuji Computed Radiography (FCR) in the diagnosis of spinal disorders. FCR is a new computed radiographic system which uses an energy-storage phosphorus panel called an ''Imaging Plate'' as an image sensor. The ''Imaging Plate'' can be used to obtain radiographs in exactly the same way as the screen-film combination used in conventional radiography; X-rays are exposed on the ''Imaging Plate'' instead of X-ray film in the conventional fashion, and then the ''Imaging Plate'' is calculated. The processed digital data from the scans is transformed into a picture by means of digital-to-analogue conversion. The pictures are always clear and beautiful. Plain films of the spine taken by FCR are even clearer, even in the cervicothoracic region, where it is usually difficult to obtain clear cervicothoracic films in conventional radiography. We can obtain much precise information about the spinal posterior osteophytes and grafted bone, even when the patients are immobilized in a Halo apparatus. In myelography, the pictures are also clearer; we can see how the root or roots are compressed, how the dura and cord are involved in patients with cervical disc disease, and even the very narrow space between the cord and an intradural tumor. FCR is thus very useful in observing spinal disorders, either in plain films or myelography. (author)

1987-01-01

49

Computer-aided diagnosis in chest radiography: Beyond nodules  

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-11-15

50

AEC set-up optimisation with computed radiography imaging.  

Science.gov (United States)

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

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

2005-01-01

51

Productivity and Cost Assessment of Computed Radiography, Digital Radiography, and Screen-Film for Outpatient Chest Examinations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An objective assessment and comparison of computed radiography (CR) versus digital radiography (DR) and screen-film for performing upright chest examinations on outpatients is presented in terms of workflow, productivity, speed of service, and potential cost justification. Perceived ease of use and workflow of each device is collected via a technologist opinion survey. Productivity is measured as the rate of patient throughput from normalized timing studies. The overall speed of service is ca...

Andriole, Katherine P.

2002-01-01

52

Computed radiography for characterisation of the weight-bearing knee  

International Nuclear Information System (INIS)

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

1997-07-01

53

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

2007-12-01

54

Management of pediatric radiation dose using Agfa computed radiography  

International Nuclear Information System (INIS)

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.)

2004-10-01

55

Management of pediatric radiation dose using Agfa computed radiography.  

Science.gov (United States)

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. PMID:15558263

Schaetzing, R

2004-10-01

56

Investigating the exposure class of a computed radiography system for optimisation of physical image quality for chest radiography.  

Science.gov (United States)

The purpose of this study was to investigate whether the exposure (speed) class (EC) of an Agfa computed radiography (CR) system could be used to optimise chest radiography. The frequency-dependent normalised noise-power spectra (NNPS(f)) were determined for a range of EC settings (25-1200) for a receptor dose of 4 microGy. Signal-to-noise ratios (SNRs) were measured in the lung, heart and diaphragm areas of a chest phantom with ECs of 400 and 600 at four tube voltages (60, 75, 90 and 125 kVp). As anatomical background can be a factor in detection of lung nodules, a tissue to rib ratio (TRR), which measures the ratio of pixel values in the nodule to that of rib, was measured in the lung region of the phantom to assess the suppression of the rib at ECs of 400 and 600. The NNPS(f) at ECs lower than 400 was relatively high. The NNPS(f) at EC 600 was found to be 7% lower when averaged over all frequencies than that at EC 400. The statistical significance of this difference was verified. The EC 800 and EC 1200 settings offered no extra advantages in terms of lowering frequency-dependent noise. The EC 600 setting offered improvements in SNR of between 10% and 18% in the lung, 11% and 16% in the heart, and 15% and 20% in the diaphragm compared with EC 400. Statistical analysis verified the significant difference. The EC 600 setting increased the TRR, thereby helping to suppress rib. This work indicates that an exposure class setting of 600 is the most appropriate for standard chest radiography, but clinical verification is required. PMID:19221185

Moore, C S; Saunderson, J R; Beavis, A W

2009-08-01

57

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

1985-01-01

58

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

59

An experimental comparison of detector performance for computed radiography systems  

International Nuclear Information System (INIS)

The intrinsic resolution, noise, and signal-to-noise transfer characteristics of five commercial digital computed radiography (CR) systems were compared using identical experimental methods. The reader/screen combinations evaluated were Agfa ADC-Compact/MD-10, Agfa ADC-Compact/MD-30, Agfa ADC-Solo/MD-10, Agfa ADC-Solo/MD-30, Lumisys CR-2000/MD-10, Fuji FCR-9501(HQ)/ST-Va, Kodak CR-400/GP-25, and Kodak CR-400/HR. Measurements were made at 70 and 115 kVp with 19 mm added aluminum filtration. The presampled modulation transfer functions (MTFs) of the systems were measured using an edge method. The noise power spectra (NPS) were determined by 2D Fourier analysis of uniformly exposed radiographs. The frequency-dependent detective quantum efficiencies (DQEs) were computed from the MTF, NPS, exposure measurements, and computational estimates of the ideal signal-to-noise ratios. Using 70 kVp and 0.1-0.12 mm pixel sizes, spatial frequencies of 2.1, 2.0, 2.2, 1.9, 2.0, 2.0, 2.3, 2.3, and 3.5 cycles/mm were measured at 0.2 MTF for the eight reader/screen combinations, respectively. Using 70 kVp, 7.74x10-8 C/kg (0.3 mR), and 0.1-0.12 mm pixel sizes, DQE(0.15) values of 20.3%, 22.9%, 24.6%, 28.6%, 22.2%, 30.0%, 29.5%, and 17.3% were obtained for the eight combinations, respectively. The corresponding values at 115 kVp were 15.9%, 18.5%, 21.5%, 21.8%, 15.3%, 23.1%, 22.3%, and 13.8%, respectively. The findings of the study demonstrate the pixel size, orientation, beam quality, screen, and reader dependencies of image quality in CR systems. The physical performance of the systems having standard-resolution screens demonstrated similar resolution performance but more notable variations in DQE. The one high-resolution screen tested had reduced DQE and increased MTF at high frequencies

2002-04-01

60

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)

2012-09-26

 
 
 
 
61

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

International Nuclear Information System (INIS)

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

2013-10-01

62

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-10-15

63

Quality assurance of computed and digital radiography systems  

International Nuclear Information System (INIS)

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

2007-04-18

64

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)

2013-08-01

65

Conventional radiography and computed tomography of cardiac assist devices  

Energy Technology Data Exchange (ETDEWEB)

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

Scheffel, Hans; Stolzmann, Paul; Desbiolles, Lotus; Leschka, Sebastian; Frauenfelder, Thomas; Schertler, Thomas; Marincek, Borut; Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); Wilhelm, Markus J.; Lachat, Mario [University Hospital Zurich, Clinic for Cardiovascular Surgery, Zurich (Switzerland)

2009-09-15

66

Industrial radiography with Ir-192 using computed radiographic technique  

International Nuclear Information System (INIS)

The aim of this research is to study the utilization of a low activity Ir-192 gamma source for industrial radiographic testing using the Computed Radiography (CR) system. Due to a photo-salbutamol Imaging Plate (I P) using in CR is much more radiation sensitive than a type II film with lead foil intensifying screen, the exposure time with CR can be significantly reduced. For short-lived gamma-ray source like Ir-192 source, the exposure time must be proportionally increased until it is not practical particularly for thick specimens. Generally, when the source decays to an activity of about 5 Ci or less, it will be returned to the manufacturer as a radioactive waste. In this research, the optimum conditions for radiography of a 20 mm thick welded steel sample with 2.4 Ci Ir-192 was investigated using the CR system with high resolution image plate, i.e. type Bas-SR of the Fuji Film Co. Ltd. The I P was sandwiched by a pair of 0.25 mm thick Pb intensifying sere en. Low energy scattered radiations was filtered by placing another Pb sheet with a thickness of 3 mm under the cassette. It was found that the CR image could give a contrast sensitivity of 2.5 % using only 3-minute exposure time which was comparable to the image taken by the type II film with Pb intensifying screen using the exposure time of 45 minutes

2003-06-01

67

Management of pediatric radiation dose using Fuji computed radiography  

Energy Technology Data Exchange (ETDEWEB)

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

MacCutcheon, D.W. [FUJIFILM Medical Systems U.S.A., Inc., Stamford, CT (United States)

2004-10-01

68

Recognition and prevention of computed radiography image artifacts.  

Science.gov (United States)

Initiated by complaints of image artifacts, a thorough visual and radiographic investigation of 197 Fuji, 35 Agfa, and 37 Kodak computed radiography (CR) cassettes with imaging plates (IPs) in clinical use at four radiology departments was performed. The investigation revealed that the physical deterioration of the cassettes and IPs was more extensive than previously believed. It appeared that many of the image artifacts were the direct result of premature wear of the cassettes and imaging plates. The results indicate that a quality control program for CR cassettes and IPs is essential and should include not only cleaning of the cassettes and imaging plates on a regular basis, but also visual and radiographic image inspection to limit the occurrence of image artifacts and to prolong the life cycle of the CR equipment. PMID:16710796

Hammerstrom, Kevin; Aldrich, John; Alves, Len; Ho, Andrew

2006-09-01

69

Paediatric entrance doses from exposure index in computed radiography  

Energy Technology Data Exchange (ETDEWEB)

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 {mu}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 practical approach to automatically extract parameters contained in the DICOM header, for the calculation of patient dose values for the CR modality.

Vano, E; Martinez, D; Fernandez, J M; Ordiales, J M; Prieto, C; Floriano, A [Medical Physics Service, San Carlos University Hospital, 28040 Madrid (Spain); Ten, J I [Diagnostic Radiology Service, San Carlos University Hospital, 28040 Madrid (Spain)], E-mail: eliseo@med.ucm.es

2008-06-21

70

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 practical approach to automatically extract parameters contained in the DICOM header, for the calculation of patient dose values for the CR modality

2008-06-21

71

Paediatric entrance doses from exposure index in computed radiography.  

Science.gov (United States)

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 microGy) for the age bands of 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 practical approach to automatically extract parameters contained in the DICOM header, for the calculation of patient dose values for the CR modality. PMID:18523350

Vano, E; Martinez, D; Fernandez, J M; Ordiales, J M; Prieto, C; Floriano, A; Ten, J I

2008-06-21

72

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)

2009-01-01

73

Subtraction radiography and computer assisted densitometric analyses of standardized radiographs. A comparison study with /sup 125/I absorptiometry  

Energy Technology Data Exchange (ETDEWEB)

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 /sup 125/I 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 /sup 125/I absorptiometry (r=0.82-0.94). (author).

Ortmann, L.F.; Dunford, R.; McHenry, K.; Hausmann, E.

1985-01-01

74

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 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

2006-11-01

75

Advanced multiple beam equalization radiography (AMBER) combined with computed radiography. Preliminary evaluation.  

Science.gov (United States)

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. PMID:8369179

de Rooy, T P; Oestmann, J W; Schultze Kool, L J; Vrooman, H; Buchmann, F

1993-09-01

76

Advanced multiple beam equalization radiography (AMBER) combined with computed radiography; Preliminary evaluation  

Energy Technology Data Exchange (ETDEWEB)

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.).

Rooy, T.P.W. de (Academisch Ziekenhuis, Leiden (Netherlands) Philips Medizin Systeme GmbH, Hamburg (Germany)); Oestmann, J.W. (Academisch Ziekenhuis, Leiden (Netherlands) Philips Medizin Systeme GmbH, Hamburg (Germany)); Schultze Kool, L.J. (Academisch Ziekenhuis, Leiden (Netherlands) Philips Medizin Systeme GmbH, Hamburg (Germany)); Vrooman, H. (Academisch Ziekenhuis, Leiden (Netherlands) Philips Medizin Systeme GmbH, Hamburg (Germany)); Buchmann, F. (Academisch Ziekenhuis, Leiden (Netherlands) Philips Medizin Systeme GmbH, Hamburg (Germany))

1993-09-01

77

Image reader testing system in the X(?)-ray imaging plate-computed radiography  

International Nuclear Information System (INIS)

Image reader testing system in the X(?)-ray imaging plate computed radiography is described. A scanning laser reader device are studied. It consists of scanning light source, optical system, optical scanner and imaging plate driver etc

1992-09-01

78

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

1990-11-25

79

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

80

Optimising the use of computed radiography in pediatric chest imaging.  

Science.gov (United States)

The objective of this study was to analyze image quality of chest examinations in pediatric patients using computed radiography (CR) obtained with a wide range of doses to suggest the appropriate parameters for optimal image quality. A sample of 240 chest images in four age ranges was randomly selected from the examinations performed during 2004. Images were obtained using a CR system and were evaluated independently by three radiologists. Each image was scored using criteria proposed by the European Guidelines on Quality Criteria in Pediatrics. Mean global scoring and scoring of individual criteria more sensitive to noise were used to evaluate image quality. Agfa dose level (DL) was in the range 1.20 to 2.85. It was found that there was not significant correlation (R < 0.5) between image quality and DL for any of the age ranges for either global score or for individual criteria more related to noise. The mean value of DL was in the ranges 1.9-2.1 for the four age bands. From this study, a DL value of 1.6 is proposed for pediatric CR chest imaging. This could yield a reduction of approximately a factor of 2.5 in mean patient entrance surface doses. PMID:17851716

Sanchez Jacob, R; Vano-Galvan, E; Vano, E; Gomez Ruiz, N; Fernandez Soto, J M; Martinez Barrio, D; Prieto, C

2009-04-01

 
 
 
 
81

Performance characterization of computed radiography based mammography systems  

Science.gov (United States)

Computed Radiography (CR) is a cost-effective technology for digital mammography. In order to optimize the quality of images obtained using CR Mammography, we characterized the effect on image quality of the electrooptical components of the CR imaging chain. The metrics used to assess the image quality included the Contrast to Noise Ratio (CNR), Modulation Transfer Function (MTF), Noise Power Spectrum (NPS), Detective Quantum Efficiency (DQE) and Contrast Detail Response Phantom (CDMAM 3.4 Artinis Medical Systems). An 18×24 cm high-resolution granular phosphor imaging plate (AGFA MM3.0) was used to acquire the images. Contrast detail was measured using a GUI developed for the CDMAM phantom that was scored by independent observers. The range of theoretically acceptable values measured for the CR laser was (5-36) mW and voltage range for PMT's was (4-8) V. The light detection amplifier was investigated, and the optimal Laser Power and PMT gain used for scanning was measured. The tools that we used (CNR, MTF, NPS, DQE and Contrast-detail phantom) provided an effective means of selecting optimal values for the electro-optical components of the system. The procedure enabled us to obtain good quality CR mammograms that have less noise and improved contrast.

Singh, Abhinav; Desai, Nikunj; Valentino, Daniel J.

2010-03-01

82

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

International Nuclear Information System (INIS)

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

2002-09-01

83

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-07-15

84

Analysis of X-ray radiography in atomizing sprays  

International Nuclear Information System (INIS)

Recent studies of spray-related flowfields using synchrotron-based X-ray radiography at the Advanced Photon Source (APS), Argonne National Lab, have produced useful results related to fuel mass. A companion article to this one analyzed X-ray phase contrast imaging and it identified several problems. Those results could potentially raise questions about radiography as well. Here, we simulate X-ray radiography using the same computational tools as before, but we reach a different set of conclusions. One important finding is the demonstration that radiography detects the total liquid mass along a line-of-sight, including both drops and intact liquid. As such, it can reveal liquid mass fraction, which is related to the spray breakup rate and gas entrainment; both critical for understanding of sprays. The potential for confusion between local signal reduction by diffraction and local signal reduction by absorption is also discussed. The issue is not unusual in such circumstances. This potential background problem can be avoided by careful arrangement of the experiment, and it is clear that it does not affect the results produced by the APS. (orig.)

2012-09-01

85

Analysis of X-ray radiography in atomizing sprays  

Science.gov (United States)

Recent studies of spray-related flowfields using synchrotron-based X-ray radiography at the Advanced Photon Source (APS), Argonne National Lab, have produced useful results related to fuel mass. A companion article to this one analyzed X-ray phase contrast imaging and it identified several problems. Those results could potentially raise questions about radiography as well. Here, we simulate X-ray radiography using the same computational tools as before, but we reach a different set of conclusions. One important finding is the demonstration that radiography detects the total liquid mass along a line-of-sight, including both drops and intact liquid. As such, it can reveal liquid mass fraction, which is related to the spray breakup rate and gas entrainment; both critical for understanding of sprays. The potential for confusion between local signal reduction by diffraction and local signal reduction by absorption is also discussed. The issue is not unusual in such circumstances. This potential background problem can be avoided by careful arrangement of the experiment, and it is clear that it does not affect the results produced by the APS.

Linne, Mark

2012-09-01

86

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

1982-06-06

87

Investigation of optimum X-ray beam tube voltage and filtration for chest radiography with a computed radiography system.  

Science.gov (United States)

The purpose of this study was to determine the optimum tube voltage and amount of added copper (Cu) filtration for processed chest radiographs obtained with an Agfa 75.0 Computed Radiography (CR) system. The contrast-to-noise ratio (CNR) was measured in the lung, heart/spine and diaphragm compartments of a validated chest phantom using various tube voltages and amounts of Cu filtration. The CNR was derived as a function of air kerma at the CR plate and with the effective dose. As rib contrast can interfere with detection of nodules in chest radiography, a tissue-to-rib ratio (TRR) was derived to investigate which tube voltages suppress the contrast of rib. Although processing algorithms affect the signal and noise in a way that is hard to predict, we found that, for a given set of processing parameters, the CNR was related to the plate air kerma and effective dose in a logarithmic manner (all R(2) >or=0.97). For imaging of the lung region, a low voltage (60 kVp) produced the highest CNR, whereas a high voltage (125 kVp) produced the highest TRR. In the heart/spine region, 80-125 kVp produced the highest CNR, while in the diaphragm region 60-90 kVp produced the highest CNR. For chest radiography with this CR system, the optimal tube voltage depends upon the region of interest. Of the filters tested, a 0.1 mm Cu thickness was found to provide a statistically significant increase in the CNR in the diaphragm region with tube potentials of 60 kVp and 80 kVp, without affecting the CNR in the other anatomical compartments. PMID:18662964

Moore, C S; Beavis, A W; Saunderson, J R

2008-10-01

88

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)

2012-01-01

89

Comparison of computed radiography and screen-film mammography in the detection of subtle microcalcifications  

International Nuclear Information System (INIS)

This paper compares the detectability of microcalcifications with screen-film systems and computed radiography (CR) with a storage phosphor system and to investigate the effect of an unsharp masking technique on the detectability of microcalcifications. Clustered microcalcifications (0.125-0.177 mm and 0.210-0.250 mm) were randomly superimposed on a human breast film. Two types of screen-film systems and CR images with unsharp masking and without image processing (unprocessed) were used as imaging systems. Observer performance tests by nine readers were carried out to assess the detectability of micro-calcifications on the screen-films, with unsharp masking, and on unprocessed mammograms. The observer performance data were evaluated using receiver operating characteristic (ROC) analysis. The area under the ROC curve and the true-positive localization fraction were both used as performance indexes in the evaluation

1990-11-25

90

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

CERN Multimedia

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

91

The clinical application of computed radiography in bedside photography of newborn  

International Nuclear Information System (INIS)

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

2005-09-01

92

Point-spread-function computation in fast neutron radiography  

International Nuclear Information System (INIS)

In fast neutron radiography, scintillator plates are often employed as converters of fast neutron radiation. In this paper, the simulation of interaction between BC400 scintillator plates and vertical-incidence D-T neutrons is presented, and the point spread function of scintillator plates is calculated, which exhibits a stable profile during the thickness increasing of plates from 2 mm to 100 mm. The calculation also indicates that, for a certain spatial resolution, there is not an improvement in the contrast of neutron images when the thickness of plates increases. (authors)

2006-07-01

93

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)

2012-07-01

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.

2009-12-15

95

Direct comparison of conventional and computed radiography with a dual-image recording technique  

International Nuclear Information System (INIS)

The diagnostic value of computed radiography (CR) relative to conventional screen-film radiography has not been clearly defined. To perform an objective comparison, the authors have devised a dual-image recording technique for obtaining simultaneous exposure of both a screen-film radiograph and a storage phosphor plate. Dual-image recording is achieved by loading both a conventional film and screens and a storage phosphor plate into a single cassette with the screen-film system in front. A good CR image is achieved with this technique despite a 50% dose reduction

1989-12-01

96

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.

2010-02-01

97

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

98

Fast computer processing for tissue highlighting in computed tomographic cross-sectional imaging and digital scan projection radiography  

International Nuclear Information System (INIS)

A simple, fast, computer method of simultaneously highlighting edge detail and emphasising soft-tissue contrast is discussed. An objective comparison is made with conventional blurred mask subtraction using the signal-to-noise ratio from phantom scans. The use of the algorithm for inner ear studies and digital scanned projection radiography is presented. (author)

1986-01-01

99

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

International Nuclear Information System (INIS)

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

2011-12-01

100

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)

2005-12-01

 
 
 
 
101

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)

2000-05-29

102

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1998-01-01

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

Bone height measurements of implant sites: Comparison of panoramic radiography and spiral computed tomography  

Energy Technology Data Exchange (ETDEWEB)

To compare the bone height of implant sites measured using panoramic radiography and spiral CT. The available bone height was determined for 263 maxillary and mandibular implant sites in 59 patients. Distortion was calculated using the metal bar for the panoramic radiographs. Significant differences in mean bone height between the two imaging modalities were found in maxillary and mandibular anterior regions (p<0.05). The mean difference in bone height recorded by the two techniques was smallest in the maxillary and mandibular molar areas (0.8 mm), and greatest in the mandibular anterior region (1.3 mm). With the exception of the mandibular anterior region, ninety percent of all the sites showed measurement differences within 2 mm. A safety margin of 2 to 3 mm is called for when utilizing panoramic radiography, otherwise additional imaging modality such as computed tomography is necessary to obtain accurate measurements.

Cho, Bong Hae [School of Dentistry, Pusan National University, Pusan (Korea, Republic of)

2002-06-15

106

Cephalometric radiography and computed tomography in infants undergoing craniofacial surgery  

International Nuclear Information System (INIS)

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

1983-01-01

107

Differentiating lung abscess and empyema: radiography and computed tomography  

International Nuclear Information System (INIS)

Conventional chest radiographs and computed tomographic (CT) scans of 70 inflammatory thoracic lesions in 63 patients were reviewed and scored for diagnostic features. Pathologic confirmation of the final diagnosis was available in 42% (5/12) of lung abscesses and 31% (18/58) of empyemas. CT alone was sufficient to correctly diagnose 100% (70/70) of cases. Diagnostic information not available from conventional chest radiographs was obtained in 47% (33/70) of cases; in an additional 34% of patients, CT more accurately defined the extent of disease. The most reliable CT features for the differential diagnosis of lung abscess and empyema were wall characteristics, pleural separation, and lung compression. Conventional radiographic features such as size, shape, and the angle of the lesion with the chest wall were less helpful, though also best assessed by CT

1983-01-01

108

Differentiating lung abscess and empyema: radiography and computed tomography  

Energy Technology Data Exchange (ETDEWEB)

Conventional chest radiographs and computed tomographic (CT) scans of 70 inflammatory thoracic lesions in 63 patients were reviewed and scored for diagnostic features. Pathologic confirmation of the final diagnosis was available in 42% (5/12) of lung abscesses and 31% (18/58) of empyemas. CT alone was sufficient to correctly diagnose 100% (70/70) of cases. Diagnostic information not available from conventional chest radiographs was obtained in 47% (33/70) of cases; in an additional 34% of patients, CT more accurately defined the extent of disease. The most reliable CT features for the differential diagnosis of lung abscess and empyema were wall characteristics, pleural separation, and lung compression. Conventional radiographic features such as size, shape, and the angle of the lesion with the chest wall were less helpful, though also best assessed by CT.

Stark, D.D.; Federle, M.P.; Goodman, P.C.; Podrasky, A.E.; Webb, W.R.

1983-07-01

109

[Estimation of appropriate dose for computed radiography by the threshold value of the image quality figure].  

Science.gov (United States)

We estimated the optimum dose for imaging with a computed radiography (CR) system at two different pixel sizes based on the area under curve (AUC) in receiver operating characteristic (ROC) analysis and image quality figure (IQF). Samples for ROC analysis were prepared as follows. Acryl beads, 2.0 mm in diameter, were placed on a 50.0 mm tough water phantom that was fitted with a 20.0 mm Al filter (SID 200 cm, tube voltage 80 kV). The dose level at which the film density of the screen-film system (SRO250/SRG) was 1.0+/-0.05 served as the reference dose (0.69microC/kg). Five samples were prepared by multiplying the reference dose by 1/4, 1/2, 1, 2, and 4. The samples for image quality evaluation on the basis of IQF were prepared under identical conditions. A contrast-detail (C-D) phantom was placed on a 50.0 mm tough water phantom and images were taken. The contrast threshold of these samples was determined by 10 film readers, the same as those for the ROC analysis. When the significance of differences in the AUC was tested by the paired t-test (two-sided) and the Jackknife method, significant differences were noted between the reference dose and the 1/4 or 4-times dose at the standard pixel size (0.175 mm) and smaller pixel size (0.0875 mm) size, while no significant difference was noted between the reference dose and the 1/2 or 2-times dose. In terms of IQF, no significant difference was noted between standard and smaller pixel sizes (paired t-test). The IQF data indicate that the dose level for imaging with CR can be reduced by about 30% from the reference dose. PMID:19420827

Mochizuki, Yasuo; Abe, Shinji; Yamaguchi, Kojirou

2009-04-20

110

Wajima lung cancer screening program using annual chest radiographs with computed radiography (CR)  

International Nuclear Information System (INIS)

It has been shown that chest radiography and sputum cytology are the only tests of proved value in detecting preclinical lung cancer. In the Wajima Lung Cancer Screening Program, computed radiography (CR) was utilized in a new chest radiography trial. A total of 3965 male cigarrete smokers over 45 years of age from Wajima City volunteered for this study between June 1984 and December 1989. A total of 11 lung cancers had been diagnosed by March 1990. Of these patients, 7 were detected through routine screening radiographs and 4 were detected only by sputum cytology. The radiographs which led to the diagnosis were carefully reviewed and compared to previous studies. Previous CR films showed no evidence of cancer. Therefore, it was considered that the error rate could be decreased by chest radiographs with CR. Single exposure dual-energy subtraction by means of CR was also utilized in some cases from June 1989. Subtraction images markedly improved the detection of nodules hidden under the ribs and calcifications. The dual energy subtraction technique appears promising for lung cancer screening. (author)

1991-01-01

111

Probability of detection - Comparative study of computed and film radiography for high-energy applications  

Energy Technology Data Exchange (ETDEWEB)

Full text of publication follows: Suitability of computed radiography with Ir-192, Co-60 and up to 9 MeV x-rays for weld inspections is of importance to many heavy engineering and aerospace industries. CR is preferred because of lesser exposure and processing time as compared to film based radiography and also digital images offers other advantages such as image enhancements, quantitative measurements and easier archival. This paper describes systemic experimental approaches and image quality metrics to compare imaging performance of CR with film-based radiography. Experiments were designed using six-sigma methodology to validate performance of CR for steel thickness up to 160 mm with Ir- 192, Co-60 and x-ray energies varying from 100 kV up to 9 MeV. Weld specimens with defects such as lack of fusion, penetration, cracks, concavity, and porosities were studied for evaluating radiographic sensitivity and imaging performance of the system. Attempts were also made to quantify probability of detection using specimens with artificial and natural defects for various experimental conditions and were compared with film based systems. (authors)

Venkatachalam, R.; Venugopal, M.; Prasad, T. [NDE Modeling Lab, GE India Technology Centre, Bangalore (India)

2007-07-01

112

Probability of detection - Comparative study of computed and film radiography for high-energy applications  

International Nuclear Information System (INIS)

Full text of publication follows: Suitability of computed radiography with Ir-192, Co-60 and up to 9 MeV x-rays for weld inspections is of importance to many heavy engineering and aerospace industries. CR is preferred because of lesser exposure and processing time as compared to film based radiography and also digital images offers other advantages such as image enhancements, quantitative measurements and easier archival. This paper describes systemic experimental approaches and image quality metrics to compare imaging performance of CR with film-based radiography. Experiments were designed using six-sigma methodology to validate performance of CR for steel thickness up to 160 mm with Ir- 192, Co-60 and x-ray energies varying from 100 kV up to 9 MeV. Weld specimens with defects such as lack of fusion, penetration, cracks, concavity, and porosities were studied for evaluating radiographic sensitivity and imaging performance of the system. Attempts were also made to quantify probability of detection using specimens with artificial and natural defects for various experimental conditions and were compared with film based systems. (authors)

2007-06-25

113

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

International Nuclear Information System (INIS)

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

2006-06-01

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)

2010-10-12

115

Single kVp dual-energy technique using a computed radiography system  

International Nuclear Information System (INIS)

This study presents a novel single-exposure dual-energy computed radiography technique using photostimulable luminescent phosphor areal plate detectors. Sandwiched multiple areal detectors are used during a single-exposure technique to utilize unabsorbed flux. A decomposition algorithm, termed ''singular value decomposition windowing,'' was derived to fit the mathematical rigors of this single kVp technique. Image processing techniques used for spatial registration of the two imaging plates are discussed as well as decreasing the effect of basis projection image noise. Scatter characteristics and correction are also discussed. Basis projection images are presented: soft-tissue cancelled, bone cancelled, and monoenergy

1987-12-04

116

Finding-specific display presets for computed radiography soft-copy reading  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Much work has been done to optimize the display of cross-sectional modality imaging examinations for soft-copy reading (ie, window/level tissue presets, and format presentations such as tile and stack modes, four-on-one, nine-on-one, etc). Less attention has been paid to the display of digital forms of the conventional projection x-ray. The purpose of this study is to assess the utility of providing presets for computed radiography (CR) soft-copy display, based not on the window/level setting...

Andriole, Katherine P.; Gould, Robert G.; Webb, W. Richard

1999-01-01

117

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

International Nuclear Information System (INIS)

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

2010-12-01

118

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

Science.gov (United States)

To assess the diagnostic accuracy of cone beam computed tomography (CBCT) in comparison with conventional radiography for vertical root fractures, 50 of 100 teeth were subjected to vertical root fracture (VRF) and then placed in dry mandibles. 3D scans were obtained for all teeth, and conventional radiographs were used as control images. All the images were assessed by 6 observers, who determined the presence of root fractures by using a 5-point confidence rating scale. The mean area under the curve (Az) for CBCT was 0.91, and that for conventional radiography was 0.64. The difference between the modalities was statistically significant (P = 0.003). On the basis of interclass coefficient, inter-observer agreement for CBCT was 0/750, and that for conventional radiography was 0/637. Thus CBCT was shown to be significantly better than conventional periapical radiography for diagnosis of vertical root fractures in vitro. PMID:21206162

Varshosaz, Masoud; Tavakoli, Mohammad A; Mostafavi, Maryam; Baghban, Alireza A

2010-12-01

119

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

120

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

2013-11-01

 
 
 
 
121

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

Science.gov (United States)

The purpose of this study was to examine the use of three physical image quality metrics in the calibration of an automatic exposure control (AEC) device for chest radiography with a computed radiography (CR) imaging system. The metrics assessed were signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and mean effective noise equivalent quanta (eNEQm), all measured using a uniform chest phantom. Subsequent calibration curves were derived to ensure each metric was held constant across the tube voltage range. Each curve was assessed for its clinical appropriateness by generating computer simulated chest images with correct detector air kermas for each tube voltage, and grading these against reference images which were reconstructed at detector air kermas correct for the constant detector dose indicator (DDI) curve currently programmed into the AEC device. All simulated chest images contained clinically realistic projected anatomy and anatomical noise and were scored by experienced image evaluators. Constant DDI and CNR curves do not appear to provide optimized performance across the diagnostic energy range. Conversely, constant eNEQm and SNR do appear to provide optimized performance, with the latter being the preferred calibration metric given as it is easier to measure in practice. Medical physicists may use the SNR image quality metric described here when setting up and optimizing AEC devices for chest radiography CR systems with a degree of confidence that resulting clinical image quality will be adequate for the required clinical task. However, this must be done with close cooperation of expert image evaluators, to ensure appropriate levels of detector air kerma. PMID:24732020

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

2014-05-01

122

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

123

Computed radiography as a gamma ray detector-dose response and applications  

International Nuclear Information System (INIS)

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

2004-08-21

124

Radiological examination of postoperative maxillary cyst; Comparison between rotational panoramic radiography and computed tomography  

Energy Technology Data Exchange (ETDEWEB)

We compared findings obtained by rotational panoramic radiography and computed tomography in postoperative maxillary cyst diagnosed histopathologically. The results were as follows: Twenty two patients (13 males and 9 females) were studied, the average age was 45.8 years and the average period after initial surgery of maxillary sinus was 24.6 years. In the rotational panoramic radiographs, the lesion had well-defined margin in 17 cases, slightly diffuse margin in 4 cases and diffuse margin in 1 case. In the 21 cases with well-defined and slightly diffuse margin the lesion occupied the maxillary sinus horizontally in 14 cases and the inferior border extended to the alveolar area in 20 cases. The forms of the lesions were classified into four types: round type, partially round type, simular sinus type and unsettled type. the lesion was unilocular in 14 cases. The location of the lesion obtained by different procedures agreed in 18 cases. 70% of lesions grouped round or partially round types in the rotational panormamic radiography were classified into the absorbed type in the computed tomography. (author).

Naitoh, Munetaka; Shiojima, Masaru; Kikuchi, Atsushi; Fukaya, Masahiko; Kawai, Tsuyoshi (Aichi-Gakuin Univ., Nagoya (Japan). School of Dentistry)

1989-10-01

125

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

Science.gov (United States)

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

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

2004-08-01

126

Computed radiography as a gamma ray detector-dose response and applications  

Energy Technology Data Exchange (ETDEWEB)

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

O' Keeffe, D S; McLeod, R W [Department of Medical Physics and Bioengineering, Christchurch Hospital, Private Bag 4710, Christchurch (New Zealand)

2004-08-21

127

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

Science.gov (United States)

Computed radiography (CR) can be used for imaging the spatial distribution of photon emissions from radionuclides. Its wide dynamic range and good response to medium energy gamma rays reduces the need for long exposure times. Measurements of small doses can be performed without having to pre-sensitize the computed radiography plates via an x-ray exposure, as required with screen-film systems. Cassette-based Agfa MD30 and Kodak GP25 CR plates were used in applications involving the detection of gamma ray emissions from technetium-99m and iodine-131. Cassette entrance doses as small as 1 microGy (140 keV gamma rays) produce noisy images, but the images are suitable for applications such as the detection of breaks in radiation protection barriers. A consequence of the gamma ray sensitivity of CR plates is the possibility that some nuclear medicine patients may fog their x-rays if the x-ray is taken soon after their radiopharmaceutical injection. The investigation showed that such fogging is likely to be diffuse. PMID:15446787

O'Keeffe, D S; McLeod, R W

2004-08-21

128

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-01-25

129

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

International Nuclear Information System (INIS)

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

2011-01-30

130

Comparative study on computed orthopantomography and film radiographic techniques in the radiography of temporomandibular joint  

International Nuclear Information System (INIS)

Objective: To compare the computed orthopantomography (COPT) with Shriller radiography(SR), film orthopantomography (FOPT) and other traditional radiographic techniques in the radiography of temporomandibular joint (TMJ). Methods: Ninty-eight cases were randomly divided into 3 groups, and the open and close positions of TMJs of both sides were examined with SR, FOPT, and COPT, respectively. The satisfactory rates of the X-ray pictures were statistically analyzed with Pearson chi-square in SPSS10.0, and the satisfactory rates were analyzed with q test between the groups. Results: One hundred and forty-four of the open and close positions of 144 TMJ pictures of the COPT group, 128 of 128 of the FOPT group, and 6 of 120 of the SR group were satisfactory in the mandible ramus of the TMJ, with satisfactory rate being 100%, 100%, and 5%, respectively (P0.01), respectively between FOPT and COPT groups. The difference was not statistically significant. The exposure was as follows: COPT, 99-113 mAs; FOPT, 210-225 mAs; and SR, 48-75 mAs. Therefore, COPT and FOPT were superior to SR in the pictures of the mandible ramus, coronoid process, and incisure, but inferior in the joint space pictures. The satisfactory rates of the condylar process and articular tubercle were same in the 3 groups. The exposure of the FOPT group was greater than that of the COPT and SR groups. Conclusion: COPT is superior to SR and FOPT in TMJ radiography, and should be applied widely in the clinic. (authors)

2007-12-01

131

Evaluation of the image in mammography application of ALVIM statistics phantom using computed radiography (CR)  

International Nuclear Information System (INIS)

Objective: To evaluate the minimal Al2O3 mottle (calcification)and nylon fiber signal (tumor) in mammography application of ALVIM statistics phantom by computed radiography (CR). Methods: ALVIM statistics phantom consists of five Al2O3 mottles(calcification) and five nylon fiber signals(tumor) various in size and was placed on the imaging plate(IP), test image with a density of D=0.70 ± 0.05 was obtained by molybdenum target X-ray equipment with a voltage of 26 kV and by adjusting exposure and selecting appropriate image processing parameter. Four observers gave it the total points of the ten lines each line consisting of five signals and five noise applying of the method of five values estimation, then according to the formula of ALVIM statistics phantom figuring out a set of true positive probabilities P (S/s) and false positive probabilities P(S/n) to drawing the ROC curve and figuring out each signals probabilities Pdet, at last processing data using SPSS 10.0 statistics analysis software to acquire the smallest calcification and parenchyma tumor. Results: After acquiring the data and judging probability average value Pact of the ROC curves statistics,five Al2O3 mottle (calcification) equal to 0.6250 of 0.22 mm is minimal, and Pact equal to 0.9000 of 0.55 mm was maximal. There was no significant variation in size Pact difference between Pdet of 0.20 mm and of 0.25 mm but there was among others. Among the five varying nylon fibers size Pact equal to 0.5313 was minimal and Pdet, equal to 0.8813 of 1.00 mm was maximal. There was no significant difference between Pact of 0.45 mm and of 0.60 mm while significant difference was found between 0.45 and others. Conclusion: The method of plotting ROC curve using ALVIM statistics phantom and getting the judging probability Pdet was easy, fast and suitable to evaluate image quality control in daily clinic and popularized easily. (authors)

2006-06-01

132

Plain Radiography and computed tomography of invasive thymomas: Clinico-radiologic-pathologic correlation  

Energy Technology Data Exchange (ETDEWEB)

Fifteen computed tomography (CT) scans in nine patients with invasive thymoma are presented. The CT findings were an anterior mediastinal mass (89%), pleural deposits (78%), local infiltration of the mediastinum (100%), invasion of the cardiovascular structures (22%), lung invasion (11%) and diaphragmatic or subdiaphragmatic deposits (33%). Radiologic-pathologic correlation available in six patients showed a sensitivity of 89.5%, specificity of 87.5% and accuracy of 88.6% for CT. We conclude that CT is superior to plain radiography in the diagnosis of invasive thymoma. It provides an accurate pre-operative assessment by better demonstration of the full extent of abnormalities, and is useful in surgical planning, monitoring of therapeutic response and detecting recurrence. (authors). 19 refs., 3 tabs., 5 figs.

Yang, W.T.; Lei, K.I.K.; Metreweli, C. [Chinese Univ. of Hong Kong, Shatin (Hong Kong)

1997-05-01

133

Single new processing algorithm to replace the standard dual image format in computed chest radiography  

International Nuclear Information System (INIS)

Commercially available computed radiography (CR) systems are configured to produce dual images on a single sheet of film. One image is mildly processed, while the other is heavily processed to enhance high-frequency detail and to reduce large-area contrast. The authors of this paper modified the standard processing to provide a single image that optimizes diagnostic detail in both the lungs and mediastinum. Normal and abnormal chest CRs (Toshiba 303A System) were analyzed by three chest radiologists. The effects of various image processing parameters were studied in each case. A new processing algorithm that retained large- area contrast in the lungs while enhancing mediastinal detail was selected for further evaluation. Preliminary observer performance tests suggest that use of the new single-image format does not significantly alter diagnostic accuracy. However, use of a single image has considerable practical benefits

1990-11-25

134

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

Energy Technology Data Exchange (ETDEWEB)

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

Nakata, Mihoko

1989-04-01

135

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

International Nuclear Information System (INIS)

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

1989-01-01

136

Computed radiography by means of photostimulable BaFX:Eu2+ (X=Cl,Br,l)  

International Nuclear Information System (INIS)

BaFx:Eu2+ phosphor and the matrix crystal of it have been investigated as an efficient phosphor and a material for F-center studies respectively. These two currents of researches were connected by the finding of the photostimulated luminescence (PSL) in BaFX:Eu2+ and the study of the PSL process in these phosphors. Fuji Computed Radiography (CR) system was developed by making use of this efficient PSL phosphor in the imaging medium named Imaging Plate (IP). In this paper, the PSL mechanism in BaFX:Eu2+, the configuration and the performance of the CR system in the field of X-ray diagnostics, and its application to other fields of imaging are reviewed

1987-10-18

137

Phantom gastric mucosa for evaluating computed radiography in double-contrast upper gastrointestinal examinations  

International Nuclear Information System (INIS)

To test the clinical usefulness of computed radiography (CR) with a storage phosphor plate in upper gastrointestinal radiographic examinations, a newly devised phantom gastric mucosa was used. Simulated small elevated and depressed lesions were created on a phantom gastric mucosa made from a styrofoam 'plate'. Twenty-four sets of each CR and screen-film radiographs (SR) were obtained using phototimed exposures. Receiver operating characteristic (ROC) study and visual ranking using these images were performed. There was no significant difference between the ROC curves of CR and SR. By visual ranking, CR was equal to or better than SR in most cases. In no case was SR definitely superior to CR. CR can be safely applied in upper gastrointestinal roentgenologic examinations. (orig.)

1996-03-01

138

Analysis of electronic component failures using high-density radiography  

Energy Technology Data Exchange (ETDEWEB)

The exceptional resolution and nondestructive nature of microfocus radiography has proven to be extremely useful in the diagnosis of electronic component failures, particularly when the components are contained in sealed or encapsulated assemblies. An epoxy-encapsulated NTC thermistor and an epitaxial silicon P-N junction photodetector are examples of discrete devices in which the cause of failure was correctly hypothesized directly from a radiographic image. Subsequent destructive physical examinations confirmed the initial hypothesis and established the underlying cause in each case. The problem in a vacuum switch tube which failed to function was apparent in the radiographic image, but the underlying cause was not clear. However, radiography also showed that the position of a flat cable in the assembly could contribute to failure, an observation which resulted in a change in manufacturing procedure. In each of these instances, microradiography played a key role in decisions concerning the root cause of failure, product viability, and corrective action. 15 refs., 10 figs.

Tuohig, W.D.; Potter, T.J.

1991-11-01

139

Studies on single exposure dual energy subtraction chest computed radiography for detection of lung nodules  

International Nuclear Information System (INIS)

We assessed the usefulness of single exposure dual energy subtraction radiography in detecting lung nodules. In a phantom study, we compared the detectability of energy subtraction images (ES), standard FCR (Fuji Computed Radiography) images (FCR), or the combination of FCR and ES images (FCR+ES) with conventional film-screen images (Conv), using simulated nodules and the chest phantom. Simulated nodules were placed on each of the following 5 sites: lung field overlaid with no major pulmonary vessels or ribs, lung field with overlying pulmonary vessels, 1 overlying rib, 2 overlying ribs, and lung field with overlying mediastinum and diaphragm. A total of 300 sample films were obtained with many patterns of placement of simulated nodules. Evaluation was made using a 5-grade method by 8 radiologists. In the clinical study, 68 patients with or without lung nodules were examined. We classified the nodules by location and size. Using similar methods to those of the phantom study, we compared ES, FCR, or FCR+ES with Conv. These results were analyzed by the ROC method and statistically assessed. In the phantom study, FCR+ES were significantly superior to Conv at the site with 2 overlying ribs. ES, FCR, and FCR+ES were significantly superior to Conv at the site with overlying mediastinum and diaphragm. In the clinical study, ES and FCR+ES were significantly superior to Conv in all cases. In terms of nodular sites, ES and FCR+ES were significantly superior to Conv at the sites overlaid with 1 rib and 2 ribs. In terms of nodular sizes, ES and FCR+ES were significantly superior to Conv in both size groups. These findings indicate the usefulness of ES and FCR+ES in the detection of lung nodules. (author)

1998-10-01

140

Magnetic resonance imaging, chest radiography, computed tomography and ultrasonography in malignant lymphoma  

International Nuclear Information System (INIS)

Magnetic resonance imaging (MRI) was compared with chest radiography, computed tomography (CT) and ultrasonography (US) for demonstration of spleen and liver engagement and enlarged lymph nodes in patients with malignant lymphoma. The investigation comprised 24 patients with Hodgkin's disease (HD) and 39 with non-Hodgkin lymphoma (NHL). MRI demonstrated enlarged lymph nodes, distinctly separated from vessels, fat, muscle, liver and occasionally also pancreas without any contrast medium. The distinction between lymph nodes and spleen was, however, poor in the images. In the mediastinum, MRI was superior to chest radiography and had an accuracy similar to that of CT. In the abdomen and the pelvis MRI had slight advantages over CT in detection of enlarged lymph nodes. Compared with US the MRI results were similar in the abdomen and somewhat better in the pelvis. MRI and US were better than CT in revealing HD infiltrates in the spleen. Infiltration of NHL in the spleen was slightly better disclosed at US than at CT and MRI; most of the NHL infiltration, confirmed at histopathology, could, however, not be revealed with any of the modalities, except when the size of the spleen was considered. Regions in the spleen, displayed with low image intensity in the T2 weighted image, were most likely due to increased amount of fibrotic tissue in the lymphomatous lesions. Good demonstration of lymph nodes and lymphomatous lesions in the spleen with MRI required two sequences; one with short TR and TE (T1 weighted image) and one with long TR and TE (T2 weighted image). (orig.)

1987-01-01

 
 
 
 
141

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

International Nuclear Information System (INIS)

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. (author)

2011-01-01

142

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

143

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 CR in depiction of tiny lesion and dose reduction greatly. (authors)

2008-06-01

144

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

Energy Technology Data Exchange (ETDEWEB)

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, {gamma}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.

Rynes, J. [Ancore Corporation, 2950 Patrick Henry Drive, Santa Clara, CA 95054 (United States); Bendahan, J. [Ancore Corporation, 2950 Patrick Henry Drive, Santa Clara, CA 95054 (United States); Gozani, T. [Ancore Corporation, 2950 Patrick Henry Drive, Santa Clara, CA 95054 (United States); Loveman, R. [Ancore Corporation, 2950 Patrick Henry Drive, Santa Clara, CA 95054 (United States); Stevenson, J. [Ancore Corporation, 2950 Patrick Henry Drive, Santa Clara, CA 95054 (United States); Bell, C. [FAA William J. Hughes Technical Center, Atlantic City, NJ 08405 (United States)

1999-02-11

145

Radiography - A new field among health sciences in Finland  

Energy Technology Data Exchange (ETDEWEB)

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

Pakarinen, Ritva [Licentiate of Health Sciences, Department of Nursing Science and Health Administration, University of Oulu, Lamsantie 14 A1, 90230 Oulu (Finland)]. E-mail: ritva.pakarinen@oulu.fi; Jussila, Aino-Liisa [Doctor of Health Sciences, Department of Social and Health Care, Oulu Polytechnic, Oulu (Finland)

2007-08-15

146

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-03-15

147

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

International Nuclear Information System (INIS)

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

2012-03-01

148

Radiologic analysis of femoral acetabular impingement: from radiography to MRI  

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-03-15

149

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.)

2013-03-01

150

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

1994-01-01

151

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)

1987-01-01

152

Computed radiography for checking source position and dwell time in HDR brachytherapy: an alternative to radiographic films  

International Nuclear Information System (INIS)

Full text: Alternatives to radiographic film for quality assurance (QA) in radiotherapy are required as film processors are phased out of hospitals in favour of digital imaging equipment. Challenges in using Computed Radiography (CR) for this application include high sensitivity compared with film and the light-proof cassette which normally encloses the imaging plate and moves the front surface of the plate away from radiation sources.

2007-12-01

153

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

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The performances of three clinical computed radiography (CR) systems, (Agfa CR 75 (with CRMD 4.0 image plates), Kodak CR 850 (with Kodak GP plates) and Kodak CR 850A (with Kodak GP plates)) were evaluated using six tests recommended in American Association of Physicists in Medicine Report 93. The results indicated variable performances with majority being within acceptable limits. The variations were mainly attributed to differences in detector formulations, plate readers’ characteristics, ...

Muhogora, Wilbroad; Padovani, Renato; Bonutti, Faustino; Msaki, Peter; Kazema, R.

2011-01-01

154

R&D of LINAC based digital radiography and computed tomography instruments  

Energy Technology Data Exchange (ETDEWEB)

High-energy LINAC x-ray sources are a featured component of many industrial digital radiography (DR) and computed tomography (CT) scanners. These scanners have proven to provide crucial internal details on rocket motor, and medium to large castings. Electronic imaging systems which include LINACS usually feature a slit collimated linear-array detector. This kind of detector has distinct advantages since scatter is the dominant attenuation mechanism with high energy x-rays. Research into DR and 3D imaging has focused efforts on evaluating different 2D area-array detectors for high-energy imaging. The authors are investigating scintillator/camera systems for performing DR and CT. They will describe two simple detector packages that employ different scintillating materials and a 9- or 4-MeV LINAC source. These scanners are used to scan objects and assemblies which vary in size from 5 to 82 cm diameter. Results will be presented on: (1) small Nickel-alloy investment castings, (2) metal-ceramic castings, and (3) waste drums. Typical data acquisition, and image processing and reconstruction methods will be reported.

Schneberk, D.J.; Martz, H.E. [Lawrence Livermore National Lab., CA (United States)

1994-12-31

155

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

International Nuclear Information System (INIS)

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

2003-07-01

156

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

International Nuclear Information System (INIS)

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.

2010-05-01

157

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

158

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

1993-07-11

159

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

International Nuclear Information System (INIS)

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

2003-05-01

160

Evaluation of a computed radiography system for megavoltage photon beam dosimetry  

International Nuclear Information System (INIS)

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

2005-09-01

 
 
 
 
161

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

Energy Technology Data Exchange (ETDEWEB)

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.).

Kaelebo, P.; Goksoer, L.A.; Swaerd, L.; Peterson, L. (Oestra Sjukhuset, Goeteborg (Sweden). Dept. of Diagnostic Radiology Oestra Sjukhuset, Goeteborg (Sweden). Dept. of Orthopedic Surgery Goeteborg Univ. (Sweden). Dept. of Handicap Research)

1990-11-01

162

The use of computed radiography for routine linear accelerator and simulator quality control.  

Science.gov (United States)

Computed radiography (CR) systems were originally developed for the purpose of clinical imaging, and there has been much work published on its effectiveness as a film replacement for this end. However, there has been little published on its use for routine linear accelerator and simulator quality control, and therefore we have evaluated the use of the Kodak 2000RT system with large Agfa CR plates as a replacement for film for this function. A prerequisite for any such use is a detailed understanding of the system behaviour, hence characteristics such as spatial uniformity of response, reproducibility of spatial accuracy, plate signal decay with time and the dose-response of plates were investigated. Finally, a comparison of results obtained using CR for the measurement of radiation field dimensions was made against those from radiographic film, and found to be in agreement within 0.1 mm (mean difference for high-resolution images, 0.3 mm root mean square difference) for megavoltage images and 0.3 mm (maximum difference) for simulator images. In conclusion, the CR system has been shown to be a good alternative to radiographic film for routine quality control of linear accelerators and simulators. PMID:19398464

Patel, I; Natarajan, T; Hassan, S S; Kirby, M C

2009-10-01

163

Complete erasing of ghost images caused by deeply trapped electrons on computed radiography plates  

Science.gov (United States)

The ghost images, i.e., latent image that is unerasable with visible light (LIunVL) and reappearing image appeared on computed radiography (CR) plates were completely erased by simultaneous exposing them to filtered ultraviolet light and visible light. Three different types of CR plates (Agfa, Kodak, and Fuji) were irradiated with 50 kV X-ray beams in the dose range 8.1 mGy to 8.0 Gy, and then conventionally erased for 2 h with visible light. The remaining LIunVL could be erased by repeating 6 h simultaneous exposures to filtered ultraviolet light and visible light. After the sixth round of exposure, all the LIunVL in the three types of CR plates were erased to the same level as in an unirradiated plate and no latent images reappeared after storage at 0°C for 14 days. The absorption spectra of deep centers were specified using polychromatic ultraviolet light from a deep-ultraviolet lamp. It was found that deep centers showed a dominant peak in the absorption spectra at around 324 nm for the Agfa and Kodak plates, and at around 320 nm for the Fuji plate, in each case followed by a few small peaks. After completely erasing CR plates, these peaks were no longer observed.

Ohuchi, H.; Kondo, Y.

2011-03-01

164

Clinical evaluation of life size image of Fuji computed radiography for detection of diffuse interstitial lung diseases  

Energy Technology Data Exchange (ETDEWEB)

To evaluate the diagnostic accuracy of Fuji computed radiography (FCR) in the detection of interstitial pulmonary infiltrates, FCR life-size images at a pixel size of 0.1 mm were compared with conventional radiographs taken on the same day. Seventeen radiologists assessed the radiographs and FCR images of 56 cases, including 39 cases of various interstitial lung diseases such as interstitial pneumonia, pulmonary abnormalities associated with collagen disease, sarcoidosis, multiple pulmonary metastases, diffuse panbronchiolitis and pulmonary emphysema, and 17 normal controls. All of the pulmonary abnormalities were confirmed by high resolution CT. Observer performance tests were carried out using receiver operating characteristic analysis. In 21 cases of increased pulmonary density revealed by high resolution CT, FCR was significantly superior to conventional radiographs in the detection of reticular or linear shadows. In 11 cases of subtle interstitial abnormalities, there was no difference between FCR and conventional radiographs in the detection of any pulmonary abnormality, ground-glass opacities and reticular or linear shadows. There was also no difference between the two images in the detection of diffuse nodular shadow and pulmonary emphysema. These results indicate that FCR life-size images at a pixel size of 0.1 mm are useful for the detection of diffuse interstitial lung diseases. (author).

Akita, Shin-ichi (Niigata Univ. (Japan). School of Medicine)

1991-11-01

165

Clinical evaluation of life size image of Fuji computed radiography for detection of diffuse interstitial lung diseases  

International Nuclear Information System (INIS)

To evaluate the diagnostic accuracy of Fuji computed radiography (FCR) in the detection of interstitial pulmonary infiltrates, FCR life-size images at a pixel size of 0.1 mm were compared with conventional radiographs taken on the same day. Seventeen radiologists assessed the radiographs and FCR images of 56 cases, including 39 cases of various interstitial lung diseases such as interstitial pneumonia, pulmonary abnormalities associated with collagen disease, sarcoidosis, multiple pulmonary metastases, diffuse panbronchiolitis and pulmonary emphysema, and 17 normal controls. All of the pulmonary abnormalities were confirmed by high resolution CT. Observer performance tests were carried out using receiver operating characteristic analysis. In 21 cases of increased pulmonary density revealed by high resolution CT, FCR was significantly superior to conventional radiographs in the detection of reticular or linear shadows. In 11 cases of subtle interstitial abnormalities, there was no difference between FCR and conventional radiographs in the detection of any pulmonary abnormality, ground-glass opacities and reticular or linear shadows. There was also no difference between the two images in the detection of diffuse nodular shadow and pulmonary emphysema. These results indicate that FCR life-size images at a pixel size of 0.1 mm are useful for the detection of diffuse interstitial lung diseases. (author)

1991-01-01

166

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

International Nuclear Information System (INIS)

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

2010-05-01

167

The possibilities and limitations of direct digital radiography, ultrasound and computed tomography in diagnosing pleural mesotelioma.  

Science.gov (United States)

The goal of this study was to compare the possibilities and limitations of direct digital radiography of the chest (DDR), the use of ultrasound of the chest (US) and single slice computed tomography of the chest (CT) in diagnosing pleural mesothelioma. The study was conducted during the course of one year, on 80 patients who were successively referred to a specialized institution, under clinical suspicion of mesothelioma. The method of investigation was the comparison of findings, obtained by the reviewed methods of examination, with the pathohistologic results of a biopsy performed on each patient. The findings that were obtained by the enumerated methods were classified according to the radiologic signs that were found in each individual patient. We evaluated following radiological findings (signs), on each of the investigated methods: plaques, localized and generalized pleural thickenings, calcifications of the pleura, pleural effusions, parapneumonic effusions, pleural empyema, (round) atelectasis, pneumothorax, tumor mass or node, inflammatory infiltrate, elevation of the hemidiaphragm and osteolysis. The results of these were compared with pathohistologic findings and analyzed by means of standard statistical methods. The highest sensitivity was found for CT (94.4%), followed by US (92.6%), and by DDR (90.7%). The highest specificity was obtained with DDR (46.2%), followed by CT (35.5%) and US (23.8%). The comparison of these methods showed 90% diagnostic accuracy for DDR in relation to CT CT as an individual method best satisfied most of the criteria for diagnosing mesothelioma. No pathognomonic radiologic sign for mesothelioma was found. PMID:21874708

Popi? Ramac, Jelena; Hebrang, Andrija; Ivanovi-Herceg, Zlata; Vidjak, Vinko; Brni?, Zoran; Novaci?, Karlo; Fistoni?, Ivan

2010-12-01

168

The clinical significance of Fuji computed radiography on lateral chest radiogram  

International Nuclear Information System (INIS)

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

1995-02-01

169

Computed tomographic analysis of urinary calculi  

Energy Technology Data Exchange (ETDEWEB)

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

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

1984-03-01

170

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

Science.gov (United States)

Computed tomography was evaluated as a noninvasive technique for the diagnosis of chronic nasal disease in dogs. Computed tomographic images, radiographs, and histopathologic findings were compared in 11 dogs with chronic nasal disease. Definitive diagnosis was made following traumatic nasal flush, exploratory surgery, or necropsy. The study included 8 dogs with intranasal tumors, 2 dogs with bacterial rhinitis (Pasteurella sp), and 1 dog with mycotic rhinitis (Aspergillus sp). Computed tomography was superior to radiography in defining the extent of the disease process and in differentiating infectious rhinitis from nasal neoplasms. It defined lesions in the palate, nasopharyngeal meatus, maxillary sinus, caudal ethmoturbinates, and periorbital tissues that were difficult to demonstrate by use of conventional radiography. Tumors appeared as space-occupying lesions that obliterated the turbinates, caused deviation of the nasal septum, and eroded bone. Rhinitis appeared as a cavitating lesion that spared the paranasal sinuses, thickened and distorted the turbinates, and widened the meatus. Although morphologically distinct on computed tomographic images, infectious rhinitis and nasal neoplasms could not be differentiated by attenuation measurements or degree of contrast enhancement. Computed tomography appeared to be a reliable, noninvasive technique for the diagnosis of chronic nasal disease in dogs, and a promising alternative to diagnostic techniques currently in use. PMID:8473224

Codner, E C; Lurus, A G; Miller, J B; Gavin, P R; Gallina, A; Barbee, D D

1993-04-01

171

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

International Nuclear Information System (INIS)

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

1999-12-02

172

Computation of scattered radiation at the entrance of industrial radiography enclosures  

International Nuclear Information System (INIS)

Prior to the construction of industrial radiography enclosures, shielding calculations are made from radiation safety point of view. Generally analytical calculations are made for the primary and secondary walls and for the scattered dose at the indirect entrance of the enclosures. This method is very fast for estimation of scattered dose, but it is approximate and conservative where as Monte Carlo method is more accurate. This study compares the estimated values of the scattered dose from '192Ir and 60Co radioactive sources at the entrance for the three typical radiography enclosures using above methods. (author)

2005-11-23

173

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

174

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

175

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 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

2003-12-01

176

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

177

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

2014-05-01

178

A comparison between computed radiography and screen-film in receiver operating characteristic curve  

International Nuclear Information System (INIS)

Objective: To study and compare the characteristics of computed radiography (CR) system and screen-film system with receiver operating characteristic (ROC) curve. Methods: When H-D curves were identical basically, the images of standard phantom TRG of CR and Middle Speed Screen-Film (MSS/F) system were acquired. Then the value of one of the four post-processing parameters-GA, GS, RN and RE were changed alone, and the images of CR were acquired under each value of the four parameters. All the images were read by five radiologists using the 5-scale method, and the reading data were further analyzed using ROC method. Results: (1) The values of Az (the area under ROC curve) of CR and MSS/F systems were 0.87556 and 0.93958, MSS/F system was better than CR system (t=2.526, P=0.0355). (2) The results of gradation processing: 1) The area under the ROC curves of CR were 0.80024, 0.87556, 0.88184, 0.88928, and 0.85944, respectively, as GA=0.6, 1.0, 2.0, 3.0, and 4.0. The area under ROC curves of CR were different but remained lower than that of MSS/F system. 2) The area under the ROC curves of CR were 0.77254, 0.87556, 0.92720, 0.93356, 0.94266, and 0.93512, respectively, as GS=0.3, 0.4, 0.5, 0.6, 0.7, and 0.8. The values of Az of CR changed evidently, and some of the values were higher than that of MSS/F system. (3) The results of frequency processing: 1) The area under the ROC curves of CR were 0.87556, 0.92524, 0.94084, and 0.94148, respectively, as RE=0.5, 5.0, 10.0, and 15.0. 2) Under the condition of RE=10, the values of Az of the ROC curves of CR were 0.91438, 0.94084, 0.89518, and 0.86030, respectively, as RN=0, 3, 5, and 8. When the frequency parameter was adjusted, the area under ROC curve of CR system was higher than that of MSS/F system. Conclusions: (1) When H-D curves are identical basically, the information of CR system is significantly less than that of MSS/F system. (2) When the post processing parameters are properly adjusted, the information of CR system is higher than that of MSS/F system. (authors)

2004-09-01

179

Plate-specific gain map correction for the improvement of detective quantum efficiency in computed radiography  

International Nuclear Information System (INIS)

Purpose: The purpose of this work is to improve the noise power spectrum (NPS), and thus the detective quantum efficiency (DQE), of computed radiography (CR) images by correcting for spatial gain variations specific to individual imaging plates. CR devices have not traditionally employed gain-map corrections, unlike the case with flat-panel detectors, because of the multiplicity of plates used with each reader. The lack of gain-map correction has limited the DQE(f) at higher exposures with CR. This current work describes a feasible solution to generating plate-specific gain maps. Methods: Ten high-exposure open field images were taken with an RQA5 spectrum, using a sixth generation CR plate suspended in air without a cassette. Image values were converted to exposure, the plates registered using fiducial dots on the plate, the ten images averaged, and then high-pass filtered to remove low frequency contributions from field inhomogeneity. A gain-map was then produced by converting all pixel values in the average into fractions with mean of one. The resultant gain-map of the plate was used to normalize subsequent single images to correct for spatial gain fluctuation. To validate performance, the normalized NPS (NNPS) for all images was calculated both with and without the gain-map correction. Variations in the quality of correction due to exposure levels, beam voltage/spectrum, CR reader used, and registration were investigated. Results: The NNPS with plate-specific gain-map correction showed improvement over the noncorrected case over the range of frequencies from 0.15 to 2.5 mm-1. At high exposure (40 mR), NNPS was 50%-90% better with gain-map correction than without. A small further improvement in NNPS was seen from carefully registering the gain-map with subsequent images using small fiducial dots, because of slight misregistration during scanning. Further improvement was seen in the NNPS from scaling the gain map about the mean to account for different beam spectra. Conclusions: This study demonstrates that a simple gain-map can be used to correct for the fixed-pattern noise in a given plate and thus improve the DQE of CR imaging. Such a method could easily be implemented by manufacturers because each plate has a unique bar code and the gain-map for all plates associated with a reader could be stored for future retrieval. These experiments indicated that an improvement in NPS (and hence, DQE) is possible, depending on exposure level, over a wide range of frequencies with this technique.

2012-03-01

180

Complete erasing of ghost images on computed radiography plates and role of deeply trapped electrons  

Energy Technology Data Exchange (ETDEWEB)

Computed radiography (CR) plates made of europium-doped Ba(Sr)FBr(I) were simultaneously exposed to filtered ultraviolet light and visible light in order to erase ghost images, i.e., latent image that is unerasable with visible light (LIunVL) and reappearing one, which are particularly observed in plates irradiated with a high dose and/or cumulatively over-irradiated. CR samples showing LIunVLs were prepared by irradiating three different types of CR plates (Agfa ADC MD10, Kodak Directview Mammo EHRM2, and Fuji ST-VI) with 50 kV X-ray beams in the dose range 8.1 mGy - 8.0 Gy. After the sixth round of simultaneous 6 h exposures to filtered ultraviolet light and visible light, all the LIunVLs in the three types of CR plates were erased to the same level as in an unirradiated plate and no latent images reappeared after storage at 0 Degree-Sign C for 14 days. With conventional exposure to visible light, LIunVLs consistently remained in all types of CR plates irradiated with higher doses of X-rays and latent images reappeared in the Agfa M10 plates after storage at 0 Degree-Sign C. Electrons trapped in deep centers cause LIunVLs and they can be erased by simultaneous exposures to filtered ultraviolet light and visible light. To study electrons in deep centers, the absorption spectra were examined in all types of irradiated CR plates by using polychromatic ultraviolet light from a deep-ultraviolet lamp. It was found that deep centers showed a dominant peak in the absorption spectra at around 324 nm for the Agfa M10 and Kodak EHRM2 plates, and at around 320 nm for the Fuji ST-VI plate, in each case followed by a few small peaks. The peak heights were dose-dependent for all types of CR samples, suggesting that the number of electrons trapped in deep centers increases with the irradiation dose.

Ohuchi-Yoshida, Hiroko, E-mail: hiroko@mail.pharm.tohoku.ac.jp [Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578 (Japan); Kondo, Yasuhiro [Ishinomaki Senshu University, 1 Shinmito Minamisakai Ishinomaki-shi, Miyagi 986-8580 (Japan)

2011-12-11

 
 
 
 
181

Complete erasing of ghost images on computed radiography plates and role of deeply trapped electrons  

Science.gov (United States)

Computed radiography (CR) plates made of europium-doped Ba(Sr)FBr(I) were simultaneously exposed to filtered ultraviolet light and visible light in order to erase ghost images, i.e., latent image that is unerasable with visible light (LIunVL) and reappearing one, which are particularly observed in plates irradiated with a high dose and/or cumulatively over-irradiated. CR samples showing LIunVLs were prepared by irradiating three different types of CR plates (Agfa ADC MD10, Kodak Directview Mammo EHRM2, and Fuji ST-VI) with 50 kV X-ray beams in the dose range 8.1 mGy—8.0 Gy. After the sixth round of simultaneous 6 h exposures to filtered ultraviolet light and visible light, all the LIunVLs in the three types of CR plates were erased to the same level as in an unirradiated plate and no latent images reappeared after storage at 0 °C for 14 days. With conventional exposure to visible light, LIunVLs consistently remained in all types of CR plates irradiated with higher doses of X-rays and latent images reappeared in the Agfa M10 plates after storage at 0 °C. Electrons trapped in deep centers cause LIunVLs and they can be erased by simultaneous exposures to filtered ultraviolet light and visible light. To study electrons in deep centers, the absorption spectra were examined in all types of irradiated CR plates by using polychromatic ultraviolet light from a deep-ultraviolet lamp. It was found that deep centers showed a dominant peak in the absorption spectra at around 324 nm for the Agfa M10 and Kodak EHRM2 plates, and at around 320 nm for the Fuji ST-VI plate, in each case followed by a few small peaks. The peak heights were dose-dependent for all types of CR samples, suggesting that the number of electrons trapped in deep centers increases with the irradiation dose.

Ohuchi-Yoshida, Hiroko; Kondo, Yasuhiro

2011-12-01

182

Complete erasing of ghost images on computed radiography plates and role of deeply trapped electrons  

International Nuclear Information System (INIS)

Computed radiography (CR) plates made of europium-doped Ba(Sr)FBr(I) were simultaneously exposed to filtered ultraviolet light and visible light in order to erase ghost images, i.e., latent image that is unerasable with visible light (LIunVL) and reappearing one, which are particularly observed in plates irradiated with a high dose and/or cumulatively over-irradiated. CR samples showing LIunVLs were prepared by irradiating three different types of CR plates (Agfa ADC MD10, Kodak Directview Mammo EHRM2, and Fuji ST-VI) with 50 kV X-ray beams in the dose range 8.1 mGy - 8.0 Gy. After the sixth round of simultaneous 6 h exposures to filtered ultraviolet light and visible light, all the LIunVLs in the three types of CR plates were erased to the same level as in an unirradiated plate and no latent images reappeared after storage at 0 °C for 14 days. With conventional exposure to visible light, LIunVLs consistently remained in all types of CR plates irradiated with higher doses of X-rays and latent images reappeared in the Agfa M10 plates after storage at 0 °C. Electrons trapped in deep centers cause LIunVLs and they can be erased by simultaneous exposures to filtered ultraviolet light and visible light. To study electrons in deep centers, the absorption spectra were examined in all types of irradiated CR plates by using polychromatic ultraviolet light from a deep-ultraviolet lamp. It was found that deep centers showed a dominant peak in the absorption spectra at around 324 nm for the Agfa M10 and Kodak EHRM2 plates, and at around 320 nm for the Fuji ST-VI plate, in each case followed by a few small peaks. The peak heights were dose-dependent for all types of CR samples, suggesting that the number of electrons trapped in deep centers increases with the irradiation dose.

2011-12-11

183

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

184

Gamma radiography and its technological application  

International Nuclear Information System (INIS)

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

1962-01-01

185

Radiography - A conceptual approach  

International Nuclear Information System (INIS)

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

2008-11-01

186

Parameter analysis of radiography film for TC use  

International Nuclear Information System (INIS)

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

1988-09-23

187

The application of the Fuji Computed Radiography system for the diagnosis of pneumoconiosis; Determination of optimum conditions of image processing  

Energy Technology Data Exchange (ETDEWEB)

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

Nobechi, Tokuro (Saint Luke' s International Hospital, Tokyo (Japan)); Matsumoto, Tohru; Fukuhisa, Kenjiro; Iinuma, Takeshi; Tateno, Yukio; Shida, Hisao; Hosoda, Yutaka; Ishida, Masamitsu

1993-06-01

188

The analysis of radiation accidents in radiography and prevention methods  

International Nuclear Information System (INIS)

In the period of time from 1970 to 1979 the frequency of radiation accidents in gamma defectoscopy was 3 times higher than in X-ray defectoscopy. The analysis of accidents with gamma cameras that took place since January 1983 to August 1985 showed, that in 83% of cases the reason was improper behaviour of operator and in 17% of cases it was the equipment that failed. These accidents were classified in 5 classes and preventing means were proposed. (author)

1987-01-01

189

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

International Nuclear Information System (INIS)

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

2001-10-01

190

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)

1993-11-01

191

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 -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

2003-07-01

192

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-07-01

193

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

DEFF Research Database (Denmark)

Sensitive and reproducible tools for diagnosis, monitoring of disease activity and damage, and prognostication are essential in the management of patients with rheumatoid arthritis (RA). Conventional radiography (X-ray), the traditional gold standard for imaging in RA, is not able to detect early disease manifestations such as inflammatory changes in the soft tissues (synovitis, tensynovitis, enthesitis etc.) and the earliest stages of bone erosion. In contrast, magnetic resonance imaging (MRI) and ultrasonography (US) allow direct visualization of early inflammatory and destructive joint changes, and have several documented and potential applications in RA patients. This chapter will review key aspects of the current status and recent important advances in imaging in RA, briefly discussing X-ray and computed tomography, and particularly focusing on MRI and US. Suggestions for use in clinical trials and practice are provided Udgivelsesdato: 2008/12

Ã?stergaard, Morten; Pedersen, Susanne Juhl

2008-01-01

194

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

International Nuclear Information System (INIS)

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

2011-01-01

195

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

Science.gov (United States)

The performances of three clinical computed radiography (CR) systems, (Agfa CR 75 (with CRMD 4.0 image plates), Kodak CR 850 (with Kodak GP plates) and Kodak CR 850A (with Kodak GP plates)) were evaluated using six tests recommended in American Association of Physicists in Medicine Report 93. The results indicated variable performances with majority being within acceptable limits. The variations were mainly attributed to differences in detector formulations, plate readers' characteristics, and aging effects. The differences of the mean low contrast scores between the imaging systems for three observers were statistically significant for Agfa and Kodak CR 850A (P=0.009) and for Kodak CR systems (P=0.006) probably because of the differences in ages. However, the differences were not statistically significant between Agfa and Kodak CR 850 (P=0.284) suggesting similar perceived image quality. The study demonstrates the need to implement quality control program regularly. PMID:21897559

Muhogora, Wilbroad; Padovani, Renato; Bonutti, Faustino; Msaki, Peter; Kazema, R

2011-07-01

196

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

1986-04-21

197

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)

2009-10-02

198

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

1988-04-10

199

Direct comparison of conventional and computed radiography with a dual-image recording technique  

International Nuclear Information System (INIS)

To compare the image quality of computed radiographic (CR) with conventional screen-film images, the authors used a dual-image recording technique. Images were simultaneously acquired with a conventional screen-film combination and a storage-phosphor imaging plate loaded into a single cassette. Wiener spectra and modulation transfer function were compared for both image types. A preliminary observer performance test was conducted with chest images obtained with the dual-image recording technique on portable and fixed equipment. Analysis of physical parameters and observer test results suggests that the conventional screen-film system can provide slightly superior image quality, although the CR system has some advantage in bedside applications

1991-01-01

200

Direct comparison of conventional and computed radiography with a dual-image recording technique  

Energy Technology Data Exchange (ETDEWEB)

To compare the image quality of computed radiographic (CR) with conventional screen-film images, the authors used a dual-image recording technique. Images were simultaneously acquired with a conventional screen-film combination and a storage-phosphor imaging plate loaded into a single cassette. Wiener spectra and modulation transfer function were compared for both image types. A preliminary observer performance test was conducted with chest images obtained with the dual-image recording technique on portable and fixed equipment. Analysis of physical parameters and observer test results suggests that the conventional screen-film system can provide slightly superior image quality, although the CR system has some advantage in bedside applications.

MacMahon, H.; Sanada, S.; Doi, K.; Giger, M.; Xu, X.W.; Yin, F.F.; Montner, S.M.; Carlin, M. (Univ. of Chicago, IL (USA))

1991-03-01

 
 
 
 
201

Panoramic radiography and cone-beam computed tomography findings in preoperative examination of impacted mandibular third molars  

Science.gov (United States)

Background Preoperative radiographic examination of impacted mandibular third molars (IMTM) is essential to prevent inferior alveolar nerve injury during extraction. The purpose of this study was to evaluate the correlation between cone-beam computed tomography (CBCT) and digital panoramic radiography (DPR) findings in preoperative examination of IMTM. Methods This retrospective study included 298 teeth in 191 individuals. The relationship between the inferior alveolar canal (IAC) and the IMTM (buccal, lingual, interradicular or inferior), the position of the IMTM with respect to the IAC (contact, no contact), the morphologic shape of the mandible in the IMTM region (round, lingual extended, lingual concave), the type of IMTM (vertical, horizontal or angular) and the number of roots of the IMTM were evaluated on CBCT images. DPR images were evaluated for the number of roots of the IMTM and for the most common radiographic findings indicating a relationship between the IAC and the IMTM (darkening of the roots, diversion of the IAC, narrowing of the IAC and interruption of the white line). Data were statistically analyzed with Cramer V coefficient, Kappa statistic, chi-square and Fisher’s exact test. Results There was a significant difference in number of roots detected on DPR versus CBCT images. There was a significant association between the type of IMTM and the morphologic shape of the mandible on CBCT images. Darkening of the roots and interruption of the white line on DPR images were significantly associated with the presence of contact between the IMTM and the IAC on CBCT images. Conclusions Panoramic radiography is inadequate, whereas CBCT is useful to detect multiple roots of IMTM. When darkening of the roots and interruption of the white line are observed on panoramic images, there is increased likelihood of contact between the IMTM and the IAC. CBCT is required in these cases.

2014-01-01

202

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.

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

2014-01-01

203

Military radiography  

International Nuclear Information System (INIS)

Historic military uses of radiography are discussed in this chapter: Battle of Adowa in 1986 was the first. Besides describing the early campaigns in which radiography was used, the author discusses the problems faced: a reliable source of electricity; the problems of extreme heat; moving and breakage of equipment. Numerous historical photographs are included. 9 refs

1993-01-01

204

Neutron radiography  

International Nuclear Information System (INIS)

The basic elements of neutron radiography for nondestructive materials testing are presented, including methods of imaging and neutron sources. The costs of various neutron radiographic facilities are compared, and some unique applications are discussed. A rapid growth of the use of neutron radiography is predicted

1974-05-20

205

Identification of microorganisms for the analysis of images obtained by neutron radiography  

International Nuclear Information System (INIS)

The main difficulty in identifying infectious microorganisms is the time required to obtain a reliable result, a minimum of 72 h. We propose a reduction to about 5 h through the technique of neutron radiography. Samples containing the bacillus Escherichia coli and the cocci Staphylococcus epidermidis were incubated with B10, layered on SSNTD (CR-39) surface and irradiated in the J-9 channel from the Argonauta Reactor (IEN/CNEN) with a flux of thermal neutrons at a rate of 2.2x105 n/cm2 s. Images were observed in an optical microscope after exposure of the plates to chemical development of the latent alpha-tracks. Analysis of the images revealed morphological differences between the species, conferring the technique the perspective to use in microbial diagnosis.

2001-06-01

206

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1988-01-01

207

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 rheumatoid hands because of severe bony and articular destruction, computed tomography is necessary for the diagnosis of DRUJ subluxation. (author)

1988-01-01

208

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

209

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-06-22

210

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

Scientific Electronic Library Online (English)

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

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

211

Computer aided safety analysis  

International Nuclear Information System (INIS)

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

1987-05-25

212

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

International Nuclear Information System (INIS)

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

1993-05-01

213

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

214

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

Science.gov (United States)

Hydrostatic pulmonary edema is as an abnormal increase in extravascular water secondary to elevated pressure in the pulmonary circulation, due to congestive heart failure or intravascular volume overload. Diagnosis of hydrostatic pulmonary edema is usually based on clinical signs associated to conventional radiography findings. Interpretation of radiologic signs of cardiogenic pulmonary edema are often questionable and subject. For a bedside prompt evaluation, lung ultrasound (LUS) may assess pulmonary congestion through the evaluation of vertical reverberation artifacts, known as B-lines. These artifacts are related to multiple minimal acoustic interfaces between small water-rich structures and alveolar air, as it happens in case of thickened interlobular septa due to increase of extravascular lung water. The number, diffusion and intensity of B lines correlates with both the radiologic and invasive estimate of extravascular lung water. The integration of conventional chest radiograph with LUS can be very helpful to obtain the correct diagnosis. Computed tomography (CT) is of limited use in the work up of cardiogenic pulmonary edema, due to its high cost, little use in the emergencies and radiation exposure. However, a deep knowledge of CT signs of pulmonary edema is crucial when other similar pulmonary conditions may occasionally be in the differential diagnosis.

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

2014-01-01

215

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

International Nuclear Information System (INIS)

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

1995-11-01

216

Quality study of portal images acquired by computed radiography and screen-film system under megavoltage ray  

International Nuclear Information System (INIS)

Objective: To evaluate the quality of the portal images acquired by computed radiography (CR) system and conventional screen-film system, respectively. Methods: Imaging plates (IP) and X-ray films ora home-devised lead phantom with a leakage of 6.45% were acquired, and modulation transfer function (MTF) curves of the both images were measured using edge method. Portal images of 40 nasopharyngeal cancer patients were acquired by IP and screen-film system respectively. Two doctors with similar experience evaluated the damage degree of petrosal bone, the receiver operating characteristic (ROC) curve of CR images and general images were drawn according to two doctors evaluation results. Results: The identification frequency of CR system and screen-film system were 1.159 and 0.806 Lp/mm respectively. For doctor one, the area under ROC curve of CR images and general images were 0.802 and 0.742 respectively. For doctor two, the area under ROC curve of CR images and general images were 0.751 and 0.600 respectively. The MTF curve and ROC curve of CR are both better than those of screen-film system. Conclusion: The image quality of CR portal imaging is much better than that of screen-film system. The utility of CR in linear accelerator for portal imaging is promising in clinic. (authors)

2007-02-01

217

Direct magnification mammography in combination with computed radiography. First clinical results; Digitale Vergroesserungsmammographie in Speicherfolientechnik. Erste klinische Ergebnisse  

Energy Technology Data Exchange (ETDEWEB)

Indroduction: The combination of direct magnification mammography and computed radiography provides an improvement in spatial resolution of storage phosphor-based digital systems. A clinical study comparing conventional and digital direct magnification mammograms was performed. Methods: 100 survey mammograms in 1.5- or 1.7-fold magnification and 50 4-fold spot magnification views were obtained with a prototype direct magnification mammography system and a storage phosphor-based digital system. An intraindividual comparison of these with previous conventional radiograms of the same patients was carried. Results: The diagnostic value of digital survey mammograms using the direct magnification technique is comparable to that of conventional radiograms of the breast, especially with regard to the identification of microcalcifications and lesions and the clinical consequences. Spot magnification views performed with this combination of techniques allowed improvement in the evaluation of microcalcifications. In 15% of cases, diagnostic procedures were adjusted accordingly. Conclusion: The combination of the direct magnification technique with digital storage phosphor radiography systems allows the performance of digital mammography by improving the overall spatial resolution. The diagnostic value of digital direct magnification survey mammograms was comparable to that of conventional mammograms. Digital 4-fold spot magnification views improved visualisation of the morphologic aspects of microcalcifications. (orig.) [Deutsch] In einer klinischen Studie sollte geprueft werden, ob durch Kombination von direkter Vergroesserungsmammographie und Speicherfolientechnik die digitale Mammographie mit einer diagnostisch ausreichenden Bildqualitaet realisierbar ist und zu einer vergleichbaren oder verbesserten Mammadiagnostik fuehren kann. Mit einem Mammographiesystem fuer direktradiographische Vergroesserungsaufnahmen wurden digitale Uebersichtsmammographien in 1,5- bzw. 1,7facher Vergroesserung und Ausschnittsvergroesserungen in 4facher Vergroesserung angefertigt. Es erfolgte ein intraindividueller Vergleich von 100 digitalen Uebersichtsmammogrammen und 50 ditigalen Zielaufnahmen mit den konventionellen Voraufnahmen derselben Patientinnen. Digitale Uebersichtsmammographien in 1,5- bzw. 1,7facher Vergroesserungstechnik zeigten im Hinblick auf Herdbefunde, Mikroverkalkungen und klinische Konsequenzen keine signifikant abweichenden Ergebnisse im Vergleich zu konventionellen Uebersichtsmammogrammen. Die Ausschnittsvergroesserungen erbrachten jedoch eine verbesserte Beurteilbarkeit von Mikroverkalkungen. In{proportional_to}15% fuehrte dies zu einer Aenderung der diagnostischen Vorgehensweise. Die digitale Mammographie in Speicherfolientechnik kann durch Kombination mit der direkten Vergroesserungstechnik und der damit verbundenen Verbesserung der Ortsaufloesung erstmals sinnvoll eingesetzt werden. Uebersichtsmammogramme erbrachten eine vergleichbare diagnostische Aussagekraft, waehrend Ausschnittsvergroesserungen eine verbesserte Beurteilung von Mikroverkalkungen ermoeglichten. (orig.)

Hundertmark, C.; Breiter, N.; Funke, M.; Wiese, M.; Heyden, D. von; Grabbe, E. [Abt. Roentgendiagnostik 1, Zentrum Radiologie, Goettingen Univ. (Germany); Hermann, K.P. [Goettingen Univ. (Germany). Abt. Medizinische Physik und Biophysik

1997-08-01

218

The theoretically analysis for the parameter and performance of fast neutron radiography scintillator  

International Nuclear Information System (INIS)

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

2009-07-01

219

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

International Nuclear Information System (INIS)

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

2010-12-01

220

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

 
 
 
 
221

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

International Nuclear Information System (INIS)

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

2009-06-01

222

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

Energy Technology Data Exchange (ETDEWEB)

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

Ongeval, C. van; Bosmans, H.; Steen, A. van; Joossens, K.; Celis, V.; Nijs, K.; Rogge, F.; Marchal, G. [UZ Gasthuisberg, Department of Radiology, Leuven (Belgium); Goethem, M. van; Verslegers, I. [University Hospital of Antwerp, Department of Radiology, Wilrijk (Belgium)

2006-06-15

223

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

Science.gov (United States)

The purpose of the study was to determine prospectively the diagnostic value of a computed radiography (CR) system by comparing mammographic hard copy images with screen-film mammography (SFM). A series of 100 patients, who came for diagnostic investigation, underwent two-view SFM (Lorad M-IV Platinum) and digital mammography with a CR system (AGFA CR system). The images were obtained by double exposure, i.e. same view without removing compression of the corresponding breast. The CR images were processed with dedicated processing for mammography. Six radiologists read sets of SFM and CR images. The primary efficacy parameter was the overall diagnostic value. The secondary efficacy parameters were lesion conspicuity and lesion details (for masses and micro-calcifications), tissue visibility at chest wall and at skin line, axillary details, overall density and sharpness impression and the overall noise impression. These parameters were scored by a 7-point scoring system. "CR non-inferior to SFM" was concluded if the lower confidence interval bound exceeded 80%. The confidence interval for the overall diagnostic value was between 96.4% and 100%. Pooled analysis of the ten features for image quality comparison demonstrated for all but one feature (lesion details of the calcifications) CR non-inferiority to SFM. PMID:16518656

Van Ongeval, C; Bosmans, H; Van Steen, A; Joossens, K; Celis, V; Van Goethem, M; Verslegers, I; Nijs, K; Rogge, F; Marchal, G

2006-06-01

224

Signal differential-to-noise ratio (SdNR) in the evaluation of radiography techniques for optimisation of the industrial computed radiography  

International Nuclear Information System (INIS)

The transition from analog to digital operation which the radiography has gone through, has provided new and important challenges in the way the images are acquired and displayed. There is several acquisition system of digital image, such as for example, the computerized system, which uses Image Plates (IP). This system was used in the accomplishment of this work with the aim to study a technique capable of optimizing the acquisition of digital image. A methodology for the evaluation of image quality is through the parameter signal differential-to- noise ratio (SdNR). However, in order to compare different radiographic techniques through this system it is also necessary to calculate the Figure of Merit (FOM) that in this in case, it is given by the square of the SdNR per unit of applied dose. The method proposed in this work is about the use of IP to carry out SdNR experimental measurements and consequently FOM measurements in applications of the x-ray of pieces in aluminum. This proceeding was performed varying some specific parameters of the system, as high voltage, exposition and the use of filters in the X-rays tube exit. As a result, an SdNR was obtained for each technique, allowing in this way, to verify the behavior of the FOM in each one of them. (author)

2007-10-05

225

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

1992-11-01

226

Computer assisted functional analysis  

International Nuclear Information System (INIS)

The latest developments in computer-assisted functional analysis (CFA) in nuclear medicine are presented in about 250 papers of the 19th international annual meeting of the Society of Nuclear Medicine (Bern, September 1981). Apart from the mathematical and instrumental aspects of CFA, computerized emission tomography is given particular attention. Advances in nuclear medical diagnosis in the fields of radiopharmaceuticals, cardiology, angiology, neurology, ophthalmology, pulmonology, gastroenterology, nephrology, endocrinology, oncology and osteology are discussed. (WU)

1981-09-08

227

Neutron radiography  

International Nuclear Information System (INIS)

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

1989-04-20

228

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

International Nuclear Information System (INIS)

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

2009-12-01

229

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-12-15

230

Comparison of cone beam computed tomography and conventional panoramic radiography in assessing the topographic relationship between the mandibular canal and impacted third molars  

International Nuclear Information System (INIS)

To assess the diagnostic accuracy and value in an imaging technique field through the comparison of cone beam computed tomography and conventional panoramic radiography in assessing the topographic relationship between the mandibular canal and impacted third molars. Participants consisted of 100 patients offered the images through cone beam computed tomography and panoramic radiography. PSR-9000TM Dental CT system (Asahi Roentgen Ind. Co., Ltd, Japan) was used as the unit of cone beam computed tomography. CE-II (Asahi Roentgen Ind. Co., Ltd, Japan) and Pro Max (Planmeca Oy, Finland) were used as the unit of panoramic radiography. The images obtained through panoramic radiography were classified into 3 types according to the distance between mandibular canal and root of mandibular third molar. And they were classified into 4 types according to the proximity of radiographic feature. The images obtained through cone beam computed tomography based on the classification above were classified into 4 types according to the location between the mandibular canal and the root and were analyzed. And they were classified into buccal, inferior, lingual, and between roots, according to the location between mandibular canal and root. The data were statistically analyzed and estimated by x2-test. 1. There was no statistical significance according to 3 types (type I, type II, type III) through CBCT. 2. The results of 4 types (type A, type B, type C, type D) through CBCT were as high prevalence of CBCT 1 in type A, CBCT 2 in type B, CBCT 3 in type C, and CBCT1 in type D and those of which showed statistical significance (P value=0.03). 3. The results according to location between mandibular canal and root through CBCT recorded each 49, 25, 17, 9 as buccal, inferior, lingual, between roots. When estimating the mandibular canal and the roots through the panoramic radiography, it could be difficult to drive the views of which this estimation was considerable. Thus it is required to have an accurate diagnostic approaching through CBCT that could estimate the location between mandibular canal and roots.

2008-09-01

231

Comparison of cone beam computed tomography and conventional panoramic radiography in assessing the topographic relationship between the mandibular canal and impacted third molars  

Energy Technology Data Exchange (ETDEWEB)

To assess the diagnostic accuracy and value in an imaging technique field through the comparison of cone beam computed tomography and conventional panoramic radiography in assessing the topographic relationship between the mandibular canal and impacted third molars. Participants consisted of 100 patients offered the images through cone beam computed tomography and panoramic radiography. PSR-9000TM Dental CT system (Asahi Roentgen Ind. Co., Ltd, Japan) was used as the unit of cone beam computed tomography. CE-II (Asahi Roentgen Ind. Co., Ltd, Japan) and Pro Max (Planmeca Oy, Finland) were used as the unit of panoramic radiography. The images obtained through panoramic radiography were classified into 3 types according to the distance between mandibular canal and root of mandibular third molar. And they were classified into 4 types according to the proximity of radiographic feature. The images obtained through cone beam computed tomography based on the classification above were classified into 4 types according to the location between the mandibular canal and the root and were analyzed. And they were classified into buccal, inferior, lingual, and between roots, according to the location between mandibular canal and root. The data were statistically analyzed and estimated by x2-test. 1. There was no statistical significance according to 3 types (type I, type II, type III) through CBCT. 2. The results of 4 types (type A, type B, type C, type D) through CBCT were as high prevalence of CBCT 1 in type A, CBCT 2 in type B, CBCT 3 in type C, and CBCT1 in type D and those of which showed statistical significance (P value=0.03). 3. The results according to location between mandibular canal and root through CBCT recorded each 49, 25, 17, 9 as buccal, inferior, lingual, between roots. When estimating the mandibular canal and the roots through the panoramic radiography, it could be difficult to drive the views of which this estimation was considerable. Thus it is required to have an accurate diagnostic approaching through CBCT that could estimate the location between mandibular canal and roots.

Choi, Hyung Soo; Kim, Gyu Tae [Department of Oral and Maxillofacial Radiology, School of Dentistry, Kyung Hee University, Seoul (Korea, Republic of); Choi, Yong Suk; Hwang, Eui Hwan [Institute of Oral Biology, School of Dentistry, Kyung Hee University, Seoul (Korea, Republic of)

2008-09-15

232

Evaluation of contrast dose reduction for excretory urography using computed radiography  

Energy Technology Data Exchange (ETDEWEB)

Sixty sequential patients were randomly assigned to undergo computed urography with either our full (282 mg I/kg body weight) or half our usual dose (141 mg I/kg body weight) of intraveneous 60% diatrizoate meglumine. Three blinded observers judged automatically post-processed full dose tomograms and KUBs as qualitatively superior to both automatically post-processed and individually, interactively post-processed half dose images. Thus, post-acquisition image manipulation could not fully compensate for diminished image quality due to contrast dose reduction. (orig./HP).

Strautman, P.R.; Fajardo, L.L.; Hillman, B.J.; Yoshino, M.T.; Boyle, R.R. Jr.; Fritz, H.; Mockbee, W.B.

1989-02-01

233

Safety analysis of major unusual incidents and feed back to regulatory control system in Industrial Radiography practice  

International Nuclear Information System (INIS)

In India, 423 industrial radiography institutions are using 1100 Gamma radiography exposure devices housing approximately integrated activity of 1100 TBq (30000 Ci) of 192Ir and 110 TBq (3000 Ci) of 60Co sources. The Atomic Energy Regulatory Board (AERB) has evolved the comprehensive regulatory control programme (RCP) for enforcing radiation safety provisions in this practice. The paper describes safety analysis of, major unusual incidents during the period from 1966 to 2000 and thereby feed back to RCP. This has contributed regulatory measures, inter-ali, enforcement of regulatory provisions through frequent inspections; QA in design, operation and servicing of exposure devices/associated accessories by designers, manufacturers/suppliers and users, pre-conditions for employment of trainee radiographers and their duties, siting, location and physical security in respect of source storage room. (author)

2001-12-01

234

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

International Nuclear Information System (INIS)

Although radiography has been an established imaging modality for over a century, continuous developments have led to improvements in technique resulting in improved image quality at reduced patient dose. If one compares the technique used by Roentgen with the methods used today, one finds that a radiograph can now be obtained at a dose which is smaller by a factor of 100 or more. Nonetheless, some national surveys, particularly in the United Kingdom and in the United States of America in the 1980s and 1990s, have indicated large variations in patient doses for the same diagnostic examination, in some cases by a factor of 20 or more. This arises not only owing to the various types of equipment and accessories used by the different health care providers, but also because of operational factors. The IAEA has a statutory responsibility to establish standards for the protection of people against exposure to ionising radiation and to provide for the worldwide application of those standards. A fundamental requirement of the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (BSS), issued by the IAEA in cooperation with the FAO, ILO, WHO, PAHO and NEA, is the optimization of radiological protection of patients undergoing medical exposure. Towards its responsibility of implementation of standards and under the subprogramme of radiation safety, in 1995, the IAEA launched a coordinated research project (CRP) on radiological protection in diagnostic radiology in some countries in the Eastern European, African and Asian region. Initially, the CRP addressed radiography only and it covered wide aspects of optimisation of radiological protection. Subsequently, the scope of the CRP was extended to fluoroscopy and computed tomography (CT), but it covered primarily situation analysis of patient doses and equipment quality control. It did not cover patient dose reduction aspects in fluoroscopy and CT. The project continued up to 1999. The primary objective was to initiate a programme of optimization of protection in diagnostic radiology in each of the participating countries by introducing quality control (QC) practices, assessment of patient doses, evaluation of image quality, and identification and implementation of corrective actions. This TECDOC may be used as an approach to optimization of radiological protection for patients in diagnostic radiology

235

Allergic bronchopulmonary aspergillosis: a comparative evaluation of computed tomography with plain chest radiography  

International Nuclear Information System (INIS)

Computed tomography (CT) was done in 15 consecutive patients with allergic bronchopulmonary aspergillosis (ABPA). When compared with chest X-ray, CT was found to be superior in the diagnosis of bronchiectasis in patients with ABPA. Of the 90 lobes studied, CT detected bronchiectasis in 57 lobes and plain chest X-ray in 44 lobes. In addition to central bronchiectasis, peripheral bronchiectasis was diagnosed with CT in 18 of the 57 lobes. Follow-up CT was done in two patients after treatment for detection of progression or regression of bronchiectatic lesions. One patient showed radiological as well as clinical improvement, with a recurrence of symptoms 4 months after stopping treatment. Computed tomography showed radiological progression of bronchiectasis and the patient was successfully treated with corticosteroids (thus preventing further bronchial damage). It is concluded from this study that CT is superior to plain chest X-ray in the diagnosis of bronchiectasis in patients with ABPA. Being non-invasive, it is also helpful in monitoring the course of bronchiectasis in these patients. 12 refs., 3 tabs., 12 figs

1994-11-01

236

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 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)

2004-04-01

237

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.

Torelli S.R.

2004-01-01

238

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.

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

239

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

Energy Technology Data Exchange (ETDEWEB)

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

Chen, Tian-wu [West China Hospital of Sichuan University, Department of Radiology, Chengdu, Sichuan (China); Affiliated Hospital of North Sichuan Medical College, Medical Imaging Key Laboratory of Sichuan Province, Nanchong, Sichuan (China); Affiliated Hospital of North Sichuan Medical College, Department of Radiology, Nanchong, Sichuan (China); Yang, Zhi-gang [West China Hospital of Sichuan University, Department of Radiology, Chengdu, Sichuan (China); West China Hospital of Sichuan University, State Key Laboratory of Biotherapy, Chengdu, Sichuan (China); Dong, Zhi-hui; Chu, Zhi-gang; Yao, Jin; Wang, Qi-ling [West China Hospital of Sichuan University, Department of Radiology, Chengdu, Sichuan (China)

2010-11-15

240

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

International Nuclear Information System (INIS)

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

2010-11-01

 
 
 
 
241

Characterization of noise sources for two generations of computed radiography systems using powder and crystalline photostimulable phosphors.  

Science.gov (United States)

The performances of two generations of computed radiography (CR) were tested and compared in terms of resolution and noise characteristics. The main aim was to characterize and quantify the noise sources in the images. The systems tested were (1) Agfa CR 25.0, a flying spot reader with powder phosphor image plates (MD 40.0); and (2) the Agfa DX-S, a line-scanning CR reader with needle crystal phosphor image plates (HD 5.0). For both systems, the standard metrics of presampled modulation transfer function (MTF), normalized noise power spectra (NNPS) and detective quantum efficiency (DQE) were measured using standard radiation quality RQA5 as defined by the International Electrotechnical Commission. The various noise sources contributing to the NNPS were separated by using knowledge of their relationship with air kerma, MTF, absorption efficiency and antialiasing filters. The DX-S MTF was superior compared with the CR 25.0. The maximum difference in MTF between the DX-S scan and CR 25.0 subscan directions was 0.13 at 1.3 mm(-1). For a nominal detector air kerma of 4 microGy, the peak DQE of the DX-S was 43 (+/-3)%, which was over double that of the CR 25.0 of 18 (+/-2)%. The additive electronic noise was negligible on the CR 25.0 but calculated to be constant 3.4 x 10(-7) (+/-0.4 x 10(-7)) mm2 at 3.9 microGy on the DX-S. The DX-S has improved image quality compared with a traditional flying spot reader. The separation of the noise sources indicates that the improvements in DQE of the DX-S are due not only to the higher quantum, efficiency and MTF, but also the lower structure, secondary quantum, and excess noise. PMID:17879798

Mackenzie, Alistair; Honey, Ian D

2007-08-01

242

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 currently underway to evaluate various other methods of assessing CR plate performance

2004-01-01

243

Characterization of noise sources for two generations of computed radiography systems using powder and crystalline photostimulable phosphors  

International Nuclear Information System (INIS)

The performances of two generations of computed radiography (CR) were tested and compared in terms of resolution and noise characteristics. The main aim was to characterize and quantify the noise sources in the images. The systems tested were (1) Agfa CR 25.0, a flying spot reader with powder phosphor image plates (MD 40.0); and (2) the Agfa DX-S, a line-scanning CR reader with needle crystal phosphor image plates (HD 5.0). For both systems, the standard metrics of presampled modulation transfer function (MTF), normalized noise power spectra (NNPS) and detective quantum efficiency (DQE) were measured using standard radiation quality RQA5 as defined by the International Electrotechnical Commission. The various noise sources contributing to the NNPS were separated by using knowledge of their relationship with air kerma, MTF, absorption efficiency and antialiasing filters. The DX-S MTF was superior compared with the CR 25.0. The maximum difference in MTF between the DX-S scan and CR 25.0 subscan directions was 0.13 at 1.3 mm-1. For a nominal detector air kerma of 4 ?Gy, the peak DQE of the DX-S was 43(±3)%, which was over double that of the CR 25.0 of 18(±2)%. The additive electronic noise was negligible on the CR 25.0 but calculated to be constant 3.4x10-7 (±0.4x10-7) mm2 at 3.9 ?Gy on the DX-S. The DX-S has improved image quality compared with a traditional flying spot reader. The separation of the noise sources indicates that the improvements in DQE of the DX-S are due not only to the higher quantum, efficiency and MTF, but also the lower structure, secondary quantum, and excess noise

2007-08-01

244

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1984-01-01

245

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1983-01-01

246

The Optimisation of Lumbar Spine AP Radiography Using a Realistic Computer Model  

Energy Technology Data Exchange (ETDEWEB)

A Monte Carlo computer program has been developed to model X ray imaging systems realistically using an adult voxel phantom. Image quality is quantified in terms of contrast and signal-to-noise ratio (SNR) for six important anatomical details chosen in accordance with recent European guidelines. The program has been used to study and optimise lumbar spine (LS) radiographic systems. As an example, the effect of tube potential on contrast, SNR and effective dose for the LS AP examination is demonstrated. Optimisation involves comparison of performance with that of a reference system. Configurations (tube potential, grid and screen-film) have been found which approximately match the reference image quality, but at lower effective dose. Various configurations give good performance. Some result in significant dose reduction. For LS AP 400 and 600 speed-class systems, dose savings of 21% and 34% are achievable. The model is thus a powerful tool for system optimisation. (author)

Dance, D.R.; McVey, G.H.; Sandborg, M.; Alm Carlsson, G.; Verdun, F.R

2000-07-01

247

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

International Nuclear Information System (INIS)

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

2005-03-01

248

Computer aided failure analysis  

Energy Technology Data Exchange (ETDEWEB)

A computer aided failure analysis system (CAFA) is being developed to troubleshoot defects in electronic assemblies. Through a question and answer procedure, the system provides step by step directions to guide a troubleshooter to the fault location. A diagnostic logic routine has been established for one product and the software necessary to store and implement the routine has been developed. The time share operation (TSO) terminal has been installed and the completed system has been found to be functional. A visual aid catalog has been developed for the current CAFA routine.

Smith, R.S.

1976-09-01

249

Basic imaging properties of an indirect flat-panel detector system employing irradiation side sampling (ISS) technology for chest radiography: comparison with a computed radiographic system.  

Science.gov (United States)

The image quality and potential usefulness for patient skin-dose reduction of a newly developed flat-panel detector (FPD) system employing irradiation side sampling (ISS) were investigated and compared to a conventional computed radiography (CR) system. We used the X-ray beam quality of RQA 9 as noted in the standard evaluation method by the International Electrotechnical Commission 62220-1 to evaluate the image quality of the detector for chest radiography. The presampled modulation transfer function (MTF) of the ISS-FPD system was slightly higher than that of the CR system in the horizontal direction at more than 2.2 cycles/mm. However, the presampled MTF of the ISS-FPD system was slightly lower than that of the CR system in the vertical direction. The Wiener spectrum of the ISS-FPD system showed a 50-65 % lesser noise level than that of the CR system under the same exposure condition. The detective quantum efficiency of the ISS-FPD system was at least twice as great as that of the CR system. We conclude that the ISS-FPD system has the potential to reduce the patient skin dose compared to a conventional CR system for chest radiography. PMID:23143711

Tanaka, Nobukazu; Yano, Yuki; Yabuuchi, Hidetake; Akasaka, Tsutomu; Sasaki, Masayuki; Ohki, Masafumi; Morishita, Junji

2013-01-01

250

Shielding Benchmark Computational Analysis  

Energy Technology Data Exchange (ETDEWEB)

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).

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

2000-09-17

251

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)

2000-09-17

252

Detectability of simulated interstitial pneumonia on chest radiographs: comparison between irradiation side sampling indirect flat-panel detector and computed radiography.  

Science.gov (United States)

Objective: To compare the detectability of simulated interstitial pneumonia on chest radiographs between an irradiation side sampling indirect flat-panel detector (ISS-FPD) and computed radiography (CR). Methods: Simulated interstitial pneumonia findings (ground-glass opacity, reticular opacity and honeycomb lung) were superimposed on an anthropomorphic chest phantom. Chest radiographs were acquired under three exposure levels (4.0, 3.2 and 2.0?mAs) with an ISS-FPD and with CR. 5 thoracic radiologists evaluated 72 images for the presence or absence of a lesion over each of 6 areas. A total of 1296 observations were analysed in a receiver-operating characteristic analysis. A jackknife method was used for the statistical analysis. Results: The areas under the curves (AUCs) for the detection of simulated honeycomb lung obtained with the ISS-FPD were significantly larger than those obtained with CR at all exposure conditions. For the detection of simulated ground-glass opacity and reticular opacity, there were no significant differences between the two systems. In addition, the AUCs for the detectability of simulated honeycomb lung obtained with the ISS-FPD at all exposure levels were significantly larger than those obtained with CR at 4?mAs. Conclusion: The ISS-FPD was superior to CR for the detection of simulated honeycomb lung. Provided that the chosen model is representative of interstitial pneumonia, the use of an ISS-FPD might reduce a patient's exposure dose during the detection of interstitial pneumonia. Advances in knowledge: The ISS-FPD has shown its advantage compared with CR in the detection of honeycombing, one sign of interstitial pneumonia. PMID:24874767

Yano, Y; Yabuuchi, H; Kairada, A; Tanaka, N; Morishita, J; Akasaka, T; Matsuo, Y; Kamitani, T; Yamasaki, Y; Nagao, M; Sasaki, M

2014-08-01

253

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.

2011-01-01

254

Computed tomography in analysis of total hip endoprosthesis  

International Nuclear Information System (INIS)

16 patients with total hip endoprosthesis were investigated by high resolution computed tomography (CT) to analyse possible advantages of CT over conventional radiography. The quality of the examinations was good only in pure titanium systems: examinations of chromium-molybdenum alloys were severely deteriorated by strike artifacts. Positioning of implants is well defined in radiographs; CT provides better visualisation of the relation between implant and cortical bone. Evaluation of the contact of the shaft to the femoral corticalis is difficult in radiographs but facilitated in axial scans. Determination of relevance of CT analysis of total hip endoprosthesis remains subject to a future long-term follow-up study. (orig.)

1988-01-01

255

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

International Nuclear Information System (INIS)

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

1996-07-01

256

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

Energy Technology Data Exchange (ETDEWEB)

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

Jonsson, A. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Laurin, S. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Karner, G. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Herrlin, K. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Hochbergs, P. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Jonsson, K. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Rudling, O. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Sandstroem, S. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Sloth, M. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Svahn, G. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Pettersson, H. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden)

1996-07-01

257

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 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

2000-05-23

258

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

259

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)

2007-06-25

260

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

Energy Technology Data Exchange (ETDEWEB)

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)

Tarpani, J.R. [Sao Paulo Univ. (Brazil); Hideki Shinohara, A. [Pernambuco Federal Univ. (Brazil); Da Silva, R.R. [Rio de Janeiro Federal Univ., Rio de Janeiro-RJ (Brazil); Do Val Lacerda, N. [Compoende Aeronautica Ltda (Brazil)

2007-07-01

 
 
 
 
261

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

Energy Technology Data Exchange (ETDEWEB)

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

Nagatani, Yukihiro, E-mail: yatsushi@belle.shiga-med.ac.j [Department of Radiology, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga 520-2121 (Japan); Nitta, Norihisa [Department of Radiology, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga 520-2121 (Japan); Ikeda, Mitsuru [Department of Radiological Technology, Nagoya University School of Health Sciences, 1-20 Daikominami 1-chome, Higashi-ku, Nagoya 461-8673 (Japan); Kitahara, Hitoshi; Otani, Hideji; Seko, Ayumi; Tanaka, Toyohiko; Murakami, Yoko; Takahashi, Masashi; Murata, Kiyoshi [Department of Radiology, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga 520-2121 (Japan)

2010-09-15

262

Comparison of Combined X-Ray Radiography and Magnetic Resonance (XMR) Imaging-Versus Computed Tomography-Based Dosimetry for the Evaluation of Permanent Prostate Brachytherapy Implants  

International Nuclear Information System (INIS)

Purpose: To present a method for the dosimetric analysis of permanent prostate brachytherapy implants using a combination of stereoscopic X-ray radiography and magnetic resonance (MR) imaging (XMR) in an XMR facility, and to compare the clinical results between XMR- and computed tomography (CT)-based dosimetry. Methods and Materials: Patients who had received nonstranded iodine-125 permanent prostate brachytherapy implants underwent XMR and CT imaging 4 weeks later. Four observers outlined the prostate gland on both sets of images. Dose-volume histograms (DVHs) were derived, and agreement was compared among the observers and between the modalities. Results: A total of 30 patients were evaluated. Inherent XMR registration based on prior calibration and optical tracking required a further automatic seed registration step that revealed a median root mean square registration error of 4.2 mm (range, 1.6-11.4). The observers agreed significantly more closely on prostate base and apex positions as well as outlining contours on the MR images than on those from CT. Coefficients of variation were significantly higher for observed prostate volumes, D90, and V100 parameters on CT-based dosimetry as opposed to XMR. The XMR-based dosimetry showed little agreement with that from CT for all observers, with D90 95% limits of agreement ranges of 65, 118, 79, and 73 Gy for Observers 1, 2, 3, and 4, respectively. Conclusions: The study results showed that XMR-based dosimetry offers an alternative to other imaging modalities and registration methods with the advantages of MR-based prostate delineation and confident three-dimensional reconstruction of the implant. The XMR-derived dose-volume histograms differ from the CT-derived values and demonstrate less interobserver variability

2008-08-01

263

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

Energy Technology Data Exchange (ETDEWEB)

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

Tang, Bin; Wu, Yang [Institute of Nuclear Physics and Chemistry, CAEP, P.O. Box 919-211, Miang 621900 (China); Key Laboratory of Neutron Physics, Chinese Academy of Engineering Physics, Mianyang (China); Li, Hang, E-mail: lihang32@gmail.com [Institute of Nuclear Physics and Chemistry, CAEP, P.O. Box 919-211, Miang 621900 (China); Key Laboratory of Neutron Physics, Chinese Academy of Engineering Physics, Mianyang (China); Sun, Yong; Huo, Heyong; Liu, Bin; Tang, Ke; Yin, Wei; Chao, Chao [Institute of Nuclear Physics and Chemistry, CAEP, P.O. Box 919-211, Miang 621900 (China); Key Laboratory of Neutron Physics, Chinese Academy of Engineering Physics, Mianyang (China)

2013-11-21

264

Single Exposure Dual-Energy Digital Radiography  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study presents preliminary results of single kVp dual-energy computed radiography using laser stimulable luminescent phosphor imaging plate detectors. The single kVp technique makes use of four of these plates in a single cassette, each plate acting as an X-ray filter to the next so that the energy separation required for the dual energy basis decomposition is achieved. An analysis to determine the best operating technique for the chest is performed using computer simulation, and was fou...

Stewart, Brent K.

1987-01-01

265

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)

2008-01-01

266

Effectiveness of unannounced inspections of industrial radiography sites from radiological safety standpoint: an analysis  

International Nuclear Information System (INIS)

The regulatory authority assisted by the Radiological Physics and Advisory Division of BARC conducts announced and unannounced inspection of Industrial Radiography sites. During such inspections a variety of violations of safety requirements were observed and classified according to the severity of the radiological consequences. This paper describes the violations. It is evident that inspection would contribute to reduce such violations thereby reducing occupational and public exposures. (author)

2001-02-20

267

Radiographic Imaging in Osteomyelitis: The Role of Plain Radiography, Computed Tomography, Ultrasonography, Magnetic Resonance Imaging, and Scintigraphy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The diagnostic imaging of osteomyelitis can require the combination of diverse imaging techniques for an accurate diagnosis. Conventional radiography should always be the first imaging modality to start with, as it provides an overview of the anatomy and the pathologic conditions of the bone and soft tissues of the region of interest. Sonography is most useful in the diagnosis of fluid collections, periosteal involvement, and surrounding soft tissue abnormalities and may provide guidance for ...

Pineda, Carlos; Espinosa, Rolando; Pena, Angelica

2009-01-01

268

Realtime radiography by use of microfocus X-ray and image processing technique  

International Nuclear Information System (INIS)

It takes shorter time to apply realtime radiography for nondestructive evaluation than to apply direct radiography. It was tried to improve the realtime radiography. To improve the quality of image of realtime radiography, microfocus X-ray and image processing technique were introduced. Several industrial products were examined by the improved realtime radiography technique. Furthermore, the computed tomography technique was also introduced to the realtime radiography and it was tried to construct the X-ray tomogram from two dimentional radiographs. (author)

1996-03-01

269

Apparatus for proton radiography  

International Nuclear Information System (INIS)

An apparatus for effecting diagnostic proton radiography of patients in hospitals comprises a source of negative hydrogen ions, a synchrotron for accelerating the negative hydrogen ions to a predetermined energy, a plurality of stations for stripping extraction of a radiography beam of protons, means for sweeping the extracted beam to cover a target, and means for measuring the residual range, residual energy, or percentage transmission of protons that pass through the target. The combination of information identifying the position of the beam with information about particles traversing the subject and the back absorber is performed with the aid of a computer to provide a proton radiograph of the subject. In an alternate embodiment of the invention, a back absorber comprises a plurality of scintillators which are coupled to detectors. 10 claims, 7 drawing figures

1976-01-01

270

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

Science.gov (United States)

Currently, radiography is the only imaging technique used to diagnose bone pathology in wild animals situated under "field conditions". Nevertheless, while chronic foot disease in captive mega-herbivores is widely reported, foot radiographic imaging is confronted with scarcity of studies. Numerous hindrances lead to such limited numbers and it became very clear that the traditional perspective on bone imaging in domestic animals based on extensive studies and elaborated statistical evaluations cannot be extrapolated to their non-domestic relatives. For these reasons, the authors initiated a multi-modality imaging study and established a pioneering approach of synchronized computed tomography (CT) and digital radiography (DR), based on X-ray projections derived from three-dimensional CT reconstructed images. Whereas this approach can be applied in any clinical field, as a case of outstanding importance and great concern for zoological institutions, we selected foot bone pathologies in captive rhinoceroses to demonstrate the manifold applications of the method. Several advances were achieved, endowing the wildlife clinician with all-important tools: prototype DR exposure protocols and a modus operandi for foot positioning, advancing both traditional projections and, for the first-time, species-related radiographic views; assessment of radiographic diagnostic value for the whole foot and, in premiere, for each autopodial bone; together with additional insights into radiographic appearance of bone anatomy and pathology with a unique, simultaneous CT-DR correlation. Based on its main advantages in availing a wide range of keystone data in wildlife imaging from a limited number of examined subjects and combining advantages of CT as the golden standard method for bone diseases' diagnostic with DR's clinical feasibility under field conditions, synchronized CT-DR presents a new perspective on wildlife's health management. With this we hope to provide veterinary clinicians with concrete imaging techniques and substantial diagnostic tools, which facilitate straightforward attainment and interpretation of field radiography images taken worldwide. PMID:24963807

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

2014-01-01

271

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

Science.gov (United States)

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

Saragusty, Joseph; Goritz, Frank; Potier, Romain; Mulot, Baptiste; Maillot, Alexis; Etienne, Pascal; Bernardino, Rui; Fernandes, Teresa; Mews, Jurgen; Hildebrandt, Thomas Bernd

2014-01-01

272

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

273

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

1995-09-01

274

Digital imaging systems for plain radiography  

CERN Multimedia

Advances in digital technology led to the development of digital x-ray detectors that are currently in wide use for projection radiography, including Computed Radiography (CR) and Digital Radiography (DR). Digital Imaging Systems for Plain Radiography addresses the current technological methods available to medical imaging professionals to ensure the optimization of the radiological process concerning image quality and reduction of patient exposure. Based on extensive research by the authors and reference to the current literature, the book addresses how exposure parameters influence the diagn

Lanca, Luis

2012-01-01

275

Digital and analogue industrial radiography, application fields  

International Nuclear Information System (INIS)

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

2000-10-03

276

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.

277

Digital radiography  

International Nuclear Information System (INIS)

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

1990-10-10

278

Evaluation of panoramic radiography and axial computed tomography in cases of ameloblastoma and central giant cell granuloma of mandible.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Evaluation of mandibular mass lesions is a perplexing clinical problem. Some of these lesions have very similar clinical presentation and even similar or overlapping imaging features. Plain radiographs and orthopantomograms are frequently requisitioned for the diagnosis and are helpful in localization and characterization of these lesions. However, the specificity of diagnosis remains low. A study was undertaken to further characterize these lesions using Computed Tomography (CT) and analysis...

Gupta V; Kapoor A; Shah N; Gupta A; Mukopadhyay S

2001-01-01

279

Trace fossils revealed through x-radiography in facies analysis of Smackover Formation, southwest Alabama  

Energy Technology Data Exchange (ETDEWEB)

The use of x-radiography has been applied to slabbed cores of Jurassic Smackover limestones from southwestern Alabama to enhance the complete petrologic description of the rocks. Through x-radiography, trace fossils have been revealed in what would otherwise appear to be homogeneous rock. In these biogenic structures, organic material, partly fecal in origin, is concentrated as infill packing in actively filled burrows. A microreducing environment within the burrow results in the mineralization by finely disseminated FeS/sub 2/. The density difference between FeS/sub 2/, which has a high absorption coefficient, and the surrounding calcium carbonate highlights the burrows in the x-radiographs. This characteristic burrow mineralization is shown well in the Smackover where a Zoophycus-Thalassinoides trace-fossil assemblage has been identified. Zoophycus, a feeding structure, is characterized by concave-upward traces with whorled peaks, and is best seen in slabs cut perpendicular to bedding. Thalassinoides is a dwelling structure characterized by a boxwork burrow system and is best seen in cores cut parallel to bedding. This assemblage is restricted to facies that is laterally persistent throughout the Smackover in most of Escambia County, Alabama. This trace-fossil assemblage is found in an oolitic pelletal packstone. This unit is overlain by an oolitic grainstone and is stratigraphically above a sparsely fossiliferous, laminated wackestone and packstone. Trace fossils in this horizon are abundant, but the traces are not found in stratigraphically adjacent lithofacies. Detecting these otherwise unseen trace fossils by x-radiography assisted the paleoenvironmental interpretation of this depositional facies as a low-energy subwave-base carbonate-shelf deposit.

Esposito, R.A.; King, D.T. Jr.

1986-05-01

280

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

Science.gov (United States)

Introduction The sensitivity of CT based lung cancer screening for the detection of early lung cancer is balanced by the high number of benign lung nodules identified, the unknown consequences of radiation from the test, and the potential costs of a CT based screening program. CAD chest radiography may improve the sensitivity of standard chest radiography while minimizing the risks of CT based screening. Methods Study subjects were age 40–75 years with 10+ pack-years of smoking and/or an additional risk for developing lung cancer. Subjects were randomized to receive a PA view chest radiograph or placebo control (went through the process of being imaged but were not imaged). Images were reviewed first without then with the assistance of CAD. Actionable nodules were reported and additional evaluation was tracked. The primary outcome was the rate of developing symptomatic advanced stage lung cancer. Results 1,424 subjects were enrolled. 710 received a CAD chest radiograph, 29 of whom were found to have an actionable lung nodule on prevalence screening. Of the 15 subjects who had a chest CT performed for additional evaluation, a lung nodule was confirmed in 4, 2 of which represented lung cancer. Both of the cancers were seen by the radiologist unaided and were identified by the CAD chest radiograph. The cumulative incidence of symptomatic advanced lung cancer was 0.42 cases per 100 person-years in the control arm; there were no events in the screening arm. Conclusions Further evaluation is necessary to determine if CAD chest radiography has a role as a lung cancer screening tool. ClinicalTrials.gov identifier NCT01663155

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

2013-01-01

 
 
 
 
281

Analysis of boron utilization in sample preparation for microorganisms detection by neutron radiography technique  

International Nuclear Information System (INIS)

The neutron radiography technique applied to the microorganisms detection is the study of a new and faster alternative for diagnosis of infectious means. This work presents the parameters and the effects involved in the use of the boron as a conversion agent, that convert neutrons in a particles, capable ones of generating latent tracks in a solid state nuclear tracks detector, CR-39. The collected samples are doped with the boron by the incubation method, propitiating an interaction microorganisms/boron, that will guarantee the identification of the images of those microorganisms, through your morphology. (author)

2000-10-15

282

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

283

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-02-01

284

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

International Nuclear Information System (INIS)

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

2004-01-01

285

Digital luminescence radiography in interstitial lung disease; A receiver operating characteristics (ROC) analysis  

Energy Technology Data Exchange (ETDEWEB)

The subtle changes often found in interstitial lung disease can be difficult to evaluate at conventional radiography. In order to define the information obtained with digital radiography, it is particularly important to find out to what extent interstitial lung disease can be observed with this technique. Ninety-one patients, 56 with interstitial lung disease and 35 with normal lungs, were examined both with a digital system and with conventional film-screen technique. The examinations were reviewed independently by 4 radiologists with different experience and receiver operating characteristics (ROC) curves were constructed. The 2 systems were equal in diagnostic performance with no statistic difference between the conventional radiographs, the 2 digital images reviewed together or the 2 digital images reviewed separately. There was a significant difference between the 2 observers with the highest and the one with the lowest score only in the review of digital unsharp mask images, but otherwise no differences statistically. A lower number of false negatives and a higher number of false positives were seen with the digital unsharp mask image, producing a higher sensitivity and lower specificity. (orig.).

Kehler, M.; Albrechtsson, U.; Andresdottir, A.; Braadvik, I.; Hochbergs, P.; Larusdottir, H.; Lundin, A. (Lund Univ. (Sweden). Dept. of Diagnostic Radiology Lund Univ. (Sweden). Dept. of Lung Medicine)

1991-01-01

286

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

2005-04-11

287

Digital luminescence radiography  

International Nuclear Information System (INIS)

The introduction of picture archiving and communications systems requires primary digital image acquisition. In this paper the diagnostic value of digital luminescence radiography (10 pixels per millimeter, gray scale, 10 bits) in the investigation of the hand is compared with that of high-resolution screen-film radiography by means of receiver operating characteristic (ROC) curve methodology. Conventional (CR), digital (DR), and edge-enhanced digital (EDR) hand radiographs (100 each, 50% with arthritis or hyperparathyroidism) were read independently by five radiologists with no clinical information. Findings of four defined regions (carpus, metacarpus, proximal, and distal interphalanges) were scored on a five-point confidence scale, and a ROC analysis was performed. The gold standard was defined by consensus of three skeletral radiologists

1990-11-25

288

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.

2008-01-01

289

Quantitative 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 discernable 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 pseudocolor images in units of density. We characterize approximately 10,000 parts per year in hundreds of different configurations and compositions with this system. Images are captured using DuPont NDT55 industrial x-ray film in Daypack{trademark} packages. X-ray cabinets are of custom design, with helium flight path and a filter wheel for positioning filters if desired. The cabinets contain baffles to reduce scattered radiation and are equipped with drawer for rapid load/unload of parts. Separate units with tungsten-anode or copper-anode tubes are available. The usual operating voltage is 15 to 35 kVp. Fixturing provides for rough part positioning and precise alignment with respect to the x-ray source. Areal density standards are placed at several locations on each film. In interpreting the image, we use the standards nearest the image of the part being quantified. Because of this, small variations in x-ray flux uniformity (heel effects) are unimportant. The usual standard is a step wedge of aluminum containing 13 steps. Films are permanently labeled by imaging a perforated metal numbering strip. Data such as part number, step wedge identification, etc. are read from barcode labels and transferred to a data base for later retrieval and use in quantifying the image.

Logan, C.M.; Hernandez, J.M.; Devine, G.J.

1991-02-01

290

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

Science.gov (United States)

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

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

1993-06-01

291

Relationship between incident dose on the imaging plate and S value associated with computed radiography (CR) systems. Quantitative evaluation using uniform exposure  

International Nuclear Information System (INIS)

Practical experiments were done to quantify basic properties of the imaging plate (IP). The relation was investigated between incident dose on the IP and the S value associated with computed radiography. An acrylic phantom and uniform exposure were used for this study. The effects of the properties of incident dose (tube voltage, exposed dose, and grid application) and IP (fading time and period of use) on the S value were measured. Results indicated that determination of the S value depended on tube voltage and fading of the IP, but not on exposure dose or period of IP usage. The effects of grid use could be estimated with the grid's bucky factor and scattering factors. We concluded that these results were useful for research using the IP as an x-ray detector and for estimating incident dose by using the S value. (author)

1998-11-01

292

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)

2011-06-23

293

Nondestructive control of chemical weapons combining neutron-activation analysis and neutron-radiography techniques  

Science.gov (United States)

A project of a transportable neutron system has been designed for nondestructive detection of weapon materials such as chemical agents or explosives. The system combines imaging and identifying techniques, and uses a sealed tube neutron generator GENIE 46. The neutron emitting module is embedded in a moderator/collimator. The resulting mixed 14 MeV and thermal neutron beam allows the user to perform neutron radiography and gamma-ray spectroscopy. Substances to be detected are imaged in a first step and then identified by comparing relative spectral line intensities with those of reference materials. The moderator provides a first level protection against radiation to the operators. This project includes only industrial sub assemblies, transportable by truck to be used in open area.

Bach, Pierre; Cluzeau, S.; Le Tourneur, P.; Jaureguy, J. C.; Guir, F.

1995-03-01

294

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

295

Proton radiography in plasma  

Science.gov (United States)

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

Volpe, L.; Batani, D.; Morace, A.; Nicolai, Ph.; Regan, C.; Ravasio, A.

2011-10-01

296

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

297

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

298

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

1989-05-14

299

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

1998-11-01

300

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 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

2001-03-01

 
 
 
 
301

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-10-15

302

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

International Nuclear Information System (INIS)

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

2012-10-01

303

Computationally efficient flux variability analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background Flux variability analysis is often used to determine robustness of metabolic models in various simulation conditions. However, its use has been somehow limited by the long computation time compared to other constraint-based modeling methods. Results We present an open source implementation of flux variability analysis called fastFVA. This efficient implementation makes large-scale flux variability analysis feasible and tractable allowing more...

Gudmundsson Steinn; Thiele Ines

2010-01-01

304

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

305

Image quality analysis vs dose to the patient in digital panoramic radiography  

International Nuclear Information System (INIS)

Digital panoramic radiography is a diagnostic image technique which is increasing its use today allo over the world. Nevertheless, there is a relative lack of knowledge about the best compromise relationship between image quality and dose to the patient for these studies. Twenty one panoramic images of an anthropomorphic phantom and 205 from patients were collected using a Kodak digital equipment. Tube current, beam energy and acquisitions time were changed among studies to look for the best acquisition conditions which permit good image quality al low doses for patients. Air Kerma-Length Product was measures as dose index. Image quality was graded using objective metrics as Signal to Noise Ratio (SNR [dB]) and Contrast to Noise ratio (CNR), as well as visual evaluation with two expert observers. Reduction in dose was able, reducing mAs mainly, without affecting image quality in a sensitive way. An optimized protocol for this equipment was also obtained for standard height and weight patients. (Author)

2012-01-01

306

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.

2012-08-01

307

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

Energy Technology Data Exchange (ETDEWEB)

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

Jonsson, A. (Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden)); Borg, A.; Hannesson, P.; Herrlin, K.; Jonsson, K.; Sloth, M.; Pettersson, H.

1994-07-01

308

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

International Nuclear Information System (INIS)

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

1994-07-01

309

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

310

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, 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)

2007-11-01

311

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

Energy Technology Data Exchange (ETDEWEB)

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.)

Quaia, Emilio; Baratella, Elisa; Cernic, Stefano; Lorusso, Arianna; Casagrande, Federica; Cioffi, Vincenzo; Cova, Maria Assunta [University of Trieste (Italy), Department of Radiology, Cattinara Hospital, Trieste (Italy)

2012-09-15

312

A single-exposure dual-energy digital radiographic method using a storage phosphor computed radiography system  

Energy Technology Data Exchange (ETDEWEB)

This study focuses on the analysis and development of a single exposure dual-energy digital radiographic method using a computed radiographic system and a detector sandwich consisting of storage phosphor imaging plates and an inter-detector filter. In order to accomplish clinical utility, previous limitations were surmounted in the following areas: calibration, decomposition algorithm, image processing, scatter radiation reduction and delineation of an optimal operating technique. Singular Value Decomposition (SVD) is applied in the form of a novel decomposition algorithm, providing robust decomposition of the input images into aluminum and Lucite material equivalent images under the limitations of the single exposure process. The performance of the SVD algorithm is compared with other algorithms, along with required bit-depth. Results of requisite non-uniformity, spatial registration and noise reduction image processing are presented, as well as, scatter rejection requirements necessitating crossed 12:1 grids. Presented clinical images include application of the technique to evaluation of solitary pulmonary nodule calcium content and evaluation of rib lesions.

Stewart, B.K.

1988-01-01

313

Power Computations for Intervention Analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In many intervention analysis applications, time series data may be expensive or otherwise difficult to collect. In this case the power function is helpful, because it can be used to determine the probability that a proposed intervention analysis application will detect a meaningful change. Assuming that an underlying autoregressive integrated moving average (ARIMA) or fractional ARIMA model is known or can be estimated from the preintervention time series, the methodology for computing the r...

Mcleod, A. I.; Vingilis, E. R.

2005-01-01

314

Neutron-induced alpha radiography  

International Nuclear Information System (INIS)

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

2008-01-01

315

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1995-01-26

316

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.)

2010-01-01

317

Radiography with polarised neutrons  

Energy Technology Data Exchange (ETDEWEB)

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

Schulz, Michael L.

2010-08-20

318

Evaluation of interstitial lung diseases by use of temporal subtraction technique on computed radiography (CR) chest images. Detection and recognition of simulated lesions  

International Nuclear Information System (INIS)

Temporal subtraction images are obtained by the subtraction of a previous image from a current image. We investigated the detection of simulated lesions and also performed a recognition task in interstitial lung diseases using CR (computed radiography) images and temporal subtraction images. Five types of lung lesions, namely, ground-glass, reticular (no.1 and no.2), honeycomb, and micro-nodule patterns were simulated. Each simulated lesion was superimposed on one of the left lung, right lung, or mediastinum. Chest phantom images without and with simulated lesions were radiographed as previous and current images, respectively. Seventy-five CR and temporal subtraction images for each independent condition were used for evaluation. Five radiologists subjectively evaluated the detection and recognition of simulated lesions on CR images and temporal subtraction images. The results showed that the detection and recognition of simulated interstitial lung lesions on temporal subtraction images was significantly improved compared with CR images. Furthermore, the high detection rate was obtained with temporal subtraction images regardless of the subtlety and location of simulated lesions. (author)

2001-10-01

319

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

320

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

Science.gov (United States)

This study investigated the diagnostic accuracy of cone beam computed tomography (CBCT) compared to panoramic radiography in determining the anatomical position of the impacted third molar in relation with the mandibular canal. The study sample comprised 53 third molars from 40 patients with an increased risk of inferior alveolar nerve (IAN) injury. The panoramic and CBCT features (predictive variables) were correlated with IAN exposure and injury (outcome variables). Sensitivity and specificity of modalities in predicting IAN exposure were compared. The IAN was exposed in 23 cases during third molar removal and injury occurred in 5 patients. No significant difference in sensitivity and specificity was found between both modalities in predicting IAN exposure. To date, lingual position of the mandibular canal was significantly associated with IAN injury. CBCT was not more accurate at predicting IAN exposure during third molar removal, however, did elucidate the 3D relationship of the third molar root to the mandibular canal; the coronal sections allowed a bucco-lingual appreciation of the mandibular canal to identify cases in which a lingually placed IAN is at risk during surgery. This observation dictates the surgical approach how to remove the third molar, so the IAN will not be subjected to pressure. PMID:19640685

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

2009-09-01

 
 
 
 
321

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

International Nuclear Information System (INIS)

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

1989-01-01

322

Comparison of image quality and patient dose for chest x-ray examinations on conventional and low cost computed radiography systems  

International Nuclear Information System (INIS)

Purpose: The aims of this study were to assess if clinical chest radiographs taken at two computed radiography (CR) facilities fulfill standard quality criteria on conventional display monitor and the status of patient doses. Methods: Twenty-five adult patients were x-rayed at 102–109 kVp using Fuji type C image plates and low cost Philips PCR digitizer. Another group of 25 patients were x-rayed at 120 kVp using CRMD 4.0 image plates and conventional Agfa 75 CR digitizer. All 50 radiographs were independently assessed by four radiologists on conventional display monitor (model HP M70) with image software using six standard quality criteria. Entrance surface air kerma (ESAK) was determined using the measured incident air kerma values and exposure parameters. Results: The results show that the differences in visualization of anatomical structure in terms of image quality criteria were comparable (p > 0.05), with the exception of the visualisation of intervertebral disc spaces. However, the ESAK values for Philips PCR were higher than those for Agfa CR 75 (p < 0.001). Conclusion: Images from a low cost CR system can display anatomic details comparably to conventional CR system but at the cost of higher radiation dose. Optimisation of variables that effect patient dose is desirable when using low cost CR systems.

2012-11-01

323

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2001-03-01

324

Computer aided safety analysis 1989  

International Nuclear Information System (INIS)

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

1989-04-17

325

Neutron radiography using a transportable superconducting cyclotron  

International Nuclear Information System (INIS)

A thermal neutron radiography system based on a compact 12 MeV superconducting proton cyclotron is described. Neutrons are generated using a thick beryllium target and moderated in high density polyethylene. Monte Carlo computer simulations have been used to model the neutron and photon transport in order to optimise the performance of the system. With proton beam currents in excess of 100 ?A, it can provide high thermal neutron fluxes with L/D ratios of between 50 and 300 for various applications. Both film and electronic imaging are used to produce radiographs. The electronic imaging system consists of a 6Li-loaded ZnS intensifier screen, and a low light CCD or SIT camera. High resolution images can be recorded and computer-controlled data processing, analysis and display are possible. ((orig.))

1994-12-30

326

Evidence-based radiography  

International Nuclear Information System (INIS)

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

2008-11-01

327

Digital radiography detectors - A technical overview: Part 1  

Digital Repository Infrastructure Vision for European Research (DRIVER)

During the last two decades screen-film (SF) systems have been replaced by digital X-ray systems. The advent of digital technologies brought a number of digital solutions based on different detector and readout technologies. Improvements in technology allowed the development of new digital technologies for projection radiography such as computed radiography (CR) and digital radiography (DR). The large number of scientific papers concerning digital X-ray systems that have been published ove...

Lanc?a, Lui?s; Silva, Augusto

2009-01-01

328

Computational analysis of cerebral cortex  

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-08-15

329

Forensic Analysis of Compromised Computers  

Science.gov (United States)

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

Wolfe, Thomas

2004-01-01

330

Digital radiography  

International Nuclear Information System (INIS)

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

1993-09-01

331

Multiple-image radiography  

Energy Technology Data Exchange (ETDEWEB)

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

Wernick, Miles N [Department of Electrical and Computer Engineering, Illinois Institute of Technology, Chicago, IL 60616 (United States); Wirjadi, Oliver [Department of Electrical and Computer Engineering, Illinois Institute of Technology, Chicago, IL 60616 (United States); Chapman, Dean [Department of Physics, Illinois Institute of Technology, Chicago, IL 60616 (United States); Zhong Zhong [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973A (United States); Galatsanos, Nikolas P [Department of Electrical and Computer Engineering, Illinois Institute of Technology, Chicago, IL 60616 (United States); Yang Yongyi [Department of Electrical and Computer Engineering, Illinois Institute of Technology, Chicago, IL 60616 (United States); Brankov, Jovan G [Department of Electrical and Computer Engineering, Illinois Institute of Technology, Chicago, IL 60616 (United States); Oltulu, Oral [Department of Physics, Illinois Institute of Technology, Chicago, IL 60616 (United States); Anastasio, Mark A [Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL 60616 (United States); Muehleman, Carol [Department of Anatomy and Cell Biology, Rush Medical College, Chicago, IL 60612 (United States)

2003-12-07

332

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

International Nuclear Information System (INIS)

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

2009-11-01

333

Clinical results of CsI-detector-based dual-exposure dual energy in chest radiography  

International Nuclear Information System (INIS)

The aim of this study was to compare the sensitivity and specificity of digital chest radiography alone with digital chest radiography combined with dual-energy chest radiography in the detection of small non-calcified pulmonary nodules. Standard and dual-energy radiographs were obtained with a flat-panel digital chest system. Four radiologists reviewed digital posteroanterior chest radiographs in random order either alone or in conjunction with dual-energy soft tissue and bone images. Twenty patients with a total of 59 pulmonary nodules (median 0.5 cm, range 0.3 - 2.5 cm) confirmed by computed tomography (HU ?100) were included. A level of confidence for each diagnosis was documented using a rating scale of 1-5. Brunner and Langer's test was performed for statistical analysis. Subgroup analysis was performed for nodules greater than 1 cm, 1-0.5 cm, and <0.5 cm. For posteroanterior chest radiography, sensitivity was 33%, positive predictive value 83%, specificity 81%, and negative predictive value 30%. Review in conjunction with dual-energy images resulted in a sensitivity of 42%, positive predictive value 88%, specificity 85%, and negative predictive value 34%. The increase of nodule detection overall as well as for different size categories was significant (p<0.05). The increase of the confidence level rating was also significant (p<0.001). Dual energy added to standard posteroanterior chest radiography significantly improves the sensitivity, specificity, and confidence in detection of small non-calcified pulmonary nodules. (orig.)

2003-12-01

334

Computer aided analysis of disturbances  

International Nuclear Information System (INIS)

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

1986-01-01

335

The role of radiography and computed tomography in the diagnosis of acute dislocation of the proximal tibiofibular joint.  

Science.gov (United States)

A cadaveric study was undertaken to determine the best radiographic method of diagnosing dislocation of the proximal tibio-fibular (PTFJ) joint. Three pairs of cadaver knees were used, the right side serving as a control in each case. Plain radiographs, antero-posterior (AP) lateral and 45 degrees oblique films, and axial computed tomography (CT) scans were obtained with the joints in each of three positions: (1) anatomical, (2) dislocated anteriorly and (3) dislocated posteriorly. Similar views were obtained in the control joints with the PTFJ undisturbed. The radiographs were assessed by eight independent observers and the results were analysed. The diagnostic accuracy with plain AP and lateral radiographs was 72.5%. This was unchanged with the addition of oblique views, but improved to 82% with the control films and 86% with the axial CT scans. The authors conclude that in the diagnosis of suspected dislocation of the PTFJ, axial CT scanning is the investigation of choice. Plain AP, lateral and comparison views are useful but less accurate, while oblique views are unhelpful and unnecessary. PMID:8457820

Keogh, P; Masterson, E; Murphy, B; McCoy, C T; Gibney, R G; Kelly, E

1993-02-01

336

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...

2013-01-01

337

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

International Nuclear Information System (INIS)

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

2006-06-01

338

Estimation and analysis of the sensitivity of monoenergetic electron radiography of composite materials with fluctuating composition  

International Nuclear Information System (INIS)

A sensitivity analysis of the electron defectoscopy method for composite materials with fluctuating composition has been carried out. Quantitative evaluations of the testing sensitivity depending on inspection conditions have been obtained, and calculations of the instrumental error are shown. Based on numerical calculations, a comparison of error has been carried out between high-energy electron and X-ray testings. It is shown that when testing composite materials with a surface density of up to 7-10 g/cm2, the advantage of the electron defectoscopy method as compared to the X-ray one is the higher sensitivity and lower instrumental error. The advantage of the electron defectoscopy method over the X-ray one as regards the sensitivity is greater when a light-atom component is predomenant in the composition. A monoenergetic electron beam from a betatron with an energy of up to 30 MeV should be used for testing materials with a surface density of up to 15 g/cm2

1978-09-01

339

Application of a modern industrial radiography system in a variety of NDT missions  

International Nuclear Information System (INIS)

The report of the FORCE Institute discusses applications of computed industrial radiography as a modern tool for NDE tasks. It is shown that the digitised modalities of radiography using phosphor imaging plates are successful upgrades well able to substitute conventional industrial radiography with radiographic films as storage medium. The system described in the paper is Agfa Structurix DPS. (orig./CB)

2000-05-29

340

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

International Nuclear Information System (INIS)

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

2011-02-01

 
 
 
 
341

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

342

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)

1988-02-04

343

Piping stress analysis with personal computers  

International Nuclear Information System (INIS)

The growing market of the personal computers is providing an increasing number of professionals with unprecedented and surprisingly inexpensive computing capacity, which if using with powerful software, can enhance immensely the engineers capabilities. This paper focuses on the possibilities which opened in piping stress analysis by the widespread distribution of personal computers, on the necessary changes in the software and on the limitations of using personal computers for engineering design and analysis. Reliability and quality assurance aspects of using personal computers for nuclear applications are also mentioned. The paper resumes with personal views of the author and experiences gained during interactive graphic piping software development for personal computers. (orig./GL)

1987-01-01

344

Computer system simulation and analysis  

Science.gov (United States)

A simulation model has been developed as a tool for studying different computer system configurations. The model simulates a computer system in terms of the number and speed of hardware subsystems and the runs processed by the system in terms of equivalent adds for computation and data bits transferred for I/O. The model was written in the GPSS simulation language.

Williams, T. G.; Weatherbee, J. E.

1972-01-01

345

Computer graphics in aerodynamic analysis  

Science.gov (United States)

The use of computer graphics and its application to aerodynamic analyses on a routine basis is outlined. The mathematical modelling of the aircraft geometries and the shading technique implemented are discussed. Examples of computer graphics used to display aerodynamic flow field data and aircraft geometries are shown. A future need in computer graphics for aerodynamic analyses is addressed.

Cozzolongo, J. V.

1984-01-01

346

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

1982-06-01

347

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

348

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

349

High energy neutron radiography  

Energy Technology Data Exchange (ETDEWEB)

High-energy spallation neutron sources are now being considered in the US and elsewhere as a replacement for neutron beams produced by reactors. High-energy and high intensity neutron beams, produced by unmoderated spallation sources, open potential new vistas of neutron radiography. The authors discuss the basic advantages and disadvantages of high-energy neutron radiography, and consider some experimental results obtained at the Weapons Neutron Research (WNR) facility at Los Alamos.

Gavron, A.; Morley, K.; Morris, C.; Seestrom, S.; Ullmann, J.; Yates, G.; Zumbro, J.

1996-06-01

350

An investigation of the effect of gamma rays emitted by patients undergoing radionuclide bone scintigraphy in computed radiography during x-ray mammography examination  

International Nuclear Information System (INIS)

For convenience of outpatients, mammographies of outpatients are often taken after the injection of a radionuclide. In this study, we investigated the effects of gamma rays emitted by a patient onto imaging plates (IPs). We used a flat container filled with 99mTc solution as a planar source to irradiate gamma rays onto IPs. We changed irradiation times on each IP, and took radiographies of an ACR-specified 156 model phantom and AGH-D210F phantom. We evaluated radiography images, using visual evaluation, and profile curves, histograms, and contrast noise ratio (CNR) and root mean square (RMS) granularities analyses. The results indicated that the depiction ability of a fibrous part began to fall when the irradiation time exceeded 3 minutes. With an increase in irradiation time, an increase in pixel value and RMS granularity value and a decrease in CNR value were observed. In conclusion, IP exposed by gamma rays influenced the evaluation of phantom images. (author)

2010-03-01

351

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

Science.gov (United States)

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

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

2010-02-01

352

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

Energy Technology Data Exchange (ETDEWEB)

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

Linden, Veerle van der; Janssens, Koen [University of Antwerp, Departement Chemie, Wilrijk (Belgium); Casteele, Elke van de [Skyscan N.V., Kontich (Belgium); Thomas, Mienke Simon [Museum Boijmans Van Beuningen, Rotterdam (Netherlands); Vos, Annemie de [Antwerpen (Belgium); Janssen, Elsje [Hessenhuis, Collectiebeleid/Behoud en Beheer, Antwerpen (Belgium)

2010-02-15

353

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.

354

A comparison of the Metrecom skeletal analysis system vs plain film radiography in the measurement of sacral base angle and lumbar lordosis  

Science.gov (United States)

Fifteen male subjects were examined by a computerized three dimensional goniometer known as the Metrecom Skeletal Analysis System (Version 1.1) and by lumbar radiographs. Metrecom measurements of sacral base angle (Ferguson’s angle) and lumbar lordosis were compared to the same measurements taken from lateral lumbar radiographs. Data was analyzed using Pearson correlation coefficients. The Pearson correlation between Metrecom and radiographic sacral base angle yielded r = .236 and between Metrecom and radiographic lordosis angle was r = .519. Significant differences between radiographic sacral base angle vs Metrecom and radiographic lumbar lordosis angle vs Metrecom were found. This study suggests that the Metrecom Skeletal Analysis System (Version 1.1) has a weak association with plain film radiography in the measurement of sacral base and lumbar lordosis angle and that there is a statistically significant difference between the Metrecom and radiographic measures, as evaluated in the experiment. ImagesFigure 1

Cowherd, Geron P; Gringmuth, Robert; Nolet, Paul

1992-01-01

355

Time of flight fast neutron radiography  

Energy Technology Data Exchange (ETDEWEB)

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

Loveman, R. [Science Applications Int. Corp., Santa Clara, CA (United States); Bendahan, J. [Science Applications Int. Corp., Santa Clara, CA (United States); Gozani, T. [Science Applications Int. Corp., Santa Clara, CA (United States); Stevenson, J. [Science Applications Int. Corp., Santa Clara, CA (United States)

1995-05-01

356

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

357

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

358

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

359

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.)

1985-08-20

360

The Neutron Radiography Reactor (NRAD)  

International Nuclear Information System (INIS)

The Neutron Radiography Reactor (NRAD) operated by Argonne National Laboratory is described in this paper. NRAD was designed to allow radiography of highly absorbing reactor fuel assemblies in the vertical position on the routine basis. 7 figs

1990-08-28

 
 
 
 
361

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.)

1985-01-01

362

Computer Analysis of Doppler Signals  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper presents solutions used to proccesa sonogram, which it is determined with accuracy atthe start of the new heart cycle.The device aplication performances are based ona simple non-directional CW Doppler unit and itscapabilities to interconect with a computer over aninterface.

2011-01-01

363

Computer applications for engineering/structural analysis  

Energy Technology Data Exchange (ETDEWEB)

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

Zaslawsky, M.; Samaddar, S.K.

1991-01-01

364

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

365

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

International Nuclear Information System (INIS)

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

1997-07-02

366

SIMPLE for industrial radiography  

International Nuclear Information System (INIS)

The first thing industrial radiographers have to do before commencing radiography works is to determine manually the amount of correct exposure that the film need to be exposed in order to obtain the right density. The amount of exposure depends on many variables such as type of radioisotope, type of film, nature of test-object and its orientation, and specific arrangement related to object location and configuration. In many cases radiography works are rejected because of radiographs fail to meet certain reference criteria as defined in the applicable standard. One of the main reasons of radiograph rejection is due to inadequate exposure received by the films. SIMPLE is a software specially developed to facilitate the calculation of gamma-radiography exposure. By using this software and knowing radiographic parameters to be encountered during the work, it is expected that human error will be minimized, thus enhancing the quality and productivity of NDT jobs. (Author)

2004-07-12

367

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

1981-01-01

368

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

369

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

1983-01-01

370

Which technologies to replace gamma radiography?  

International Nuclear Information System (INIS)

Gamma radiography with iridium source is largely used in the industrial sector for the control of welds, tubes and pressure vessels as well as for monitoring corrosion. Hazards due to the handling of ionizing radiation sources (Ir192) and constraints due to a more and more demanding regulations call for alternative methods. The French 'Institut de soudure' has led a 4-year long study (Alter-X project) and has identified 3 alternative methods for the iridium gamma radiography: -) the TOFD (Time Of Flight Diffraction) which is based on the analysis of the diffraction of ultrasound waves on the edges of defects; -) phased array ultrasound which is based on a series of elementary sensors that can be handled in an individual manner by specific electronics, the sweeping is no more manual but electronic and enables the operator to localize and size defects deep under the surface; -) digit radiography that is a common radiography in which the film is replaced by a re-usable phosphorus screen that is more sensitive and can be easily digitalized and has no need for a chemical treatment to be read. Digit radiography used with Se75 (another gamma emitter) gives comparable or even better results than with Ir192 but with a dose rate cut by half at least. (A.C.)

2012-09-01

371

IUE Data Analysis Software for Personal Computers  

Science.gov (United States)

This report summarizes the work performed for the program titled, "IUE Data Analysis Software for Personal Computers" awarded under Astrophysics Data Program NRA 92-OSSA-15. The work performed was completed over a 2-year period starting in April 1994. As a result of the project, 450 IDL routines and eight database tables are now available for distribution for Power Macintosh computers and Personal Computers running Windows 3.1.

Thompson, R.; Caplinger, J.; Taylor, L.; Lawton , P.

1996-01-01

372

Low dose obstetric radiography  

International Nuclear Information System (INIS)

The basic criteria which should be adhered to for keeping radiation doses to a minimum in obstetric radiography are discussed. The possible reasons for radiographic examination (a) of the fetus and (b) for measurement of the maternal pelvis are outlined. In both cases, the techniques, the patient preparations and the different radiographic projections required are described. The maternal skin doses and the doses to the centre of the fetus are given for fetal radiography, transverse pelvimetry and lateral pelvimetry. Estimates of the doses given for earlier techniques, dating back to 1941, are also shown, showing the reduction in dose over the years. (U.K.)

1981-01-01