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1

Computed radiography.  

Science.gov (United States)

In several medical centers computed radiography has almost completely replaced the use of conventional screen-film systems for general radiography. The aim of this paper is to explain the basic principles of the four most frequently numerical detectors used in the world, with emphasis on the phosphor plates, which are the most frequently used both in hospitals and by practitioners. The other two systems are based on a receptor with selenium. The fourth uses charged coupled device (CCD) detectors. The most important principles of digital processing are then described with concentration on unsharp mask filtering. In the future computed radiography will replace standard radiology and will create a system in medicine using the power of computers to archive--with more efficiency and less space--patient medical data. The transmission of data to workstations and the processing of this data is the topic of a new field in medicine. PMID:9755796

Frija, J; de Kerviler, E; de Géry, S; Zagdanski, A M

1998-01-01

2

Computed radiography.  

UK PubMed Central (United Kingdom)

In several medical centers computed radiography has almost completely replaced the use of conventional screen-film systems for general radiography. The aim of this paper is to explain the basic principles of the four most frequently numerical detectors used in the world, with emphasis on the phosphor plates, which are the most frequently used both in hospitals and by practitioners. The other two systems are based on a receptor with selenium. The fourth uses charged coupled device (CCD) detectors. The most important principles of digital processing are then described with concentration on unsharp mask filtering. In the future computed radiography will replace standard radiology and will create a system in medicine using the power of computers to archive--with more efficiency and less space--patient medical data. The transmission of data to workstations and the processing of this data is the topic of a new field in medicine.

Frija J; de Kerviler E; de Géry S; Zagdanski AM

1998-01-01

3

Artefacts found in computed radiography.  

UK PubMed Central (United Kingdom)

Artefacts on radiographic images are distracting and may compromise accurate diagnosis. Although most artefacts that occur in conventional radiography have become familiar, computed radiography (CR) systems produce artefacts that differ from those found in conventional radiography. We have encountered a variety of artefacts in CR images that were produced from four different models plate reader. These artefacts have been identified and traced to the imaging plate, plate reader, image processing software or laser printer or to operator error. Understanding the potential sources of CR artefacts will aid in identifying and resolving problems quickly and help prevent future occurrences.

Cesar LJ; Schueler BA; Zink FE; Daly TR; Taubel JP; Jorgenson LL

2001-02-01

4

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

International Nuclear Information System (INIS)

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

1989-12-01

5

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

6

Comparative analysis of mandibular anatomical variations between panoramic radiography and cone beam computed tomography.  

UK PubMed Central (United Kingdom)

PURPOSE: The objective of this study is to compare the ability of panoramic radiography and cone beam computed tomography (CBCT) in detecting anatomical variations of the mandibular canal and mental foramen. METHODS: One hundred twenty-seven preoperative panoramic and CBCT images were evaluated. Two oral and maxillofacial radiologists investigated the presence of bifid mandibular canals and/or additional mental foramina on the right, left, or both sides of the mandible. Intra- and interobserver reliability was determined using Cohen's kappa coefficient. McNemar's test compared the prevalence of mandibular anatomical variations between panoramic radiography and CBCT. The significance level was set at 0.05. RESULTS: Additional mental foramen and bifid mandibular canal were detected in 1.2 and 7.4 % of the panoramic radiographs and 7.4 and 9.8 % of the CBCT images, respectively. The incidence of anatomical variations on the mandibular canal was not significantly different between both imaging modalities (P?>?0.05). CONCLUSIONS: Although CBCT provides better viewing of anatomical structures, including location, shape, and relationship with the surrounding area, panoramic radiography is a conventional imaging modality that can be used in the study of the bifid mandibular canals.

Neves FS; Nascimento MC; Oliveira ML; Almeida SM; Bóscolo FN

2013-08-01

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

2004-01-01

8

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

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

Computed radiography systems performance evaluation  

International Nuclear Information System (INIS)

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

2009-01-01

11

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

International Nuclear Information System (INIS)

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

1990-01-01

12

Alteration of computer dental radiography images.  

UK PubMed Central (United Kingdom)

This study was designed to determine if digital images stored on the hard drive of a Schick computer dental radiography system could be exported, altered, and then restored to the drive without any visible signs of alteration. Digital images were downloaded from the computer dental radiography system using an I-Omega Zip Drive, 100-MB capacity, and then opened in Corel Photo Paint where images were altered and manufacturer export symbols were edited. The resulting images were printed to a default printer (Fargo Foto Fun). The ease of manipulation of the exported digital images reflects the need for the manufacturer to implement safeguards so that the integrity of digital imaging cannot be compromised. Computer dental radiography has many advantages: conservation of time (instant radiographs), less radiation (50 to 60%), no chemical waste, and many viewing options. However, questions that might be raised regarding the ability of persons with minimal computer expertise, using a commercially available program to alter images should be addressed.

Bruder GA; Casale J; Goren A; Friedman S

1999-04-01

13

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

14

Computed radiography for major airway in pediatrics  

International Nuclear Information System (INIS)

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

1986-01-01

15

Optimal beam quality for abdominal computed radiography  

Energy Technology Data Exchange (ETDEWEB)

Materials and thicknesses of additional filter and X-ray tube voltage for abdominal computed radiography were investigated. Skin exposure was reduced to 35% using a 0.12 mm copper filter or a 0.12 mm gadolinium filter compared with no filtration under the same radiographic contrast and noise. Improvement of the image quality of patient exposures were achieved using these filtering materials. (author).

Oda, Nobuhiro; Murakami, Seiichi; Terada, Kunihiro; Nakano, Hideichiroh (University of Occupational and Environmental Health, Kitakyushu (Japan). Hospital); Kishimoto, Kenji

1994-05-01

16

FCR (Fuji Computed Radiography) in neurosurgery  

International Nuclear Information System (INIS)

[en] 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

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

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)

2008-01-01

19

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

International Nuclear Information System (INIS)

[en] 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.)

1993-01-01

20

Computed radiography simulation using the Monte Carlo code MCNPX  

International Nuclear Information System (INIS)

[en] 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.

2010-01-01

 
 
 
 
21

Multidimensional analysis in industrial radiography  

International Nuclear Information System (INIS)

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

1992-01-01

22

Computed radiography in neonatal intensive care  

Energy Technology Data Exchange (ETDEWEB)

The Authors report their experience in the employment of a computerized digital radiographic system in Neonatal Intensive Care. The analog screen-film system is replaced by photosensitive imaging plates, scanned after X-ray exposure by a laser that releases the digital image, which can then be manipulated on computer work-stations. In a period of twelve months about 200 chest-abdomen X-ray examinations in Neonatal Intensive Care have been performed using this method with good technical and diagnostic results. The use of digital radiography in the neonatal area is of high interest: this system produces good quality images, there is a reduction in radiation dose and 'retakes', the system allows selective enhancement of different structures and their magnification. (orig.).

Merlo, L.; Bighi, S.; Cervi, P.M.; Lupi, L. (S. Anna Hospital, Ferrara (Italy). Dept. of Radiology)

1991-02-01

23

Computed radiography in neonatal intensive care  

International Nuclear Information System (INIS)

The Authors report their experience in the employment of a computerized digital radiographic system in Neonatal Intensive Care. The analog screen-film system is replaced by photosensitive imaging plates, scanned after X-ray exposure by a laser that releases the digital image, which can then be manipulated on computer work-stations. In a period of twelve months about 200 chest-abdomen X-ray examinations in Neonatal Intensive Care have been performed using this method with good technical and diagnostic results. The use of digital radiography in the neonatal area is of high interest: this system produces good quality images, there is a reduction in radiation dose and 'retakes', the system allows selective enhancement of different structures and their magnification. (orig.).

1991-01-01

24

Evaluation and testing of computed radiography systems.  

UK PubMed Central (United Kingdom)

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

Charnock P; Connolly PA; Hughes D; Moores BM

2005-01-01

25

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

26

Nuclear imaging using Fuji Computed Radiography  

International Nuclear Information System (INIS)

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

1988-01-01

27

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

28

Noise analysis of a digital radiography system  

Energy Technology Data Exchange (ETDEWEB)

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

Arnold, B.A.; Scheibe, P.O.

1984-03-01

29

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 dete...

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

30

Noise analysis of a digital radiography system.  

Science.gov (United States)

The sources of noise in a digital video subtraction angiography system were identified and analyzed. Signal-to-noise ratios of digital radiography systems were measured using the digital image data recorded in the computer. The major sources of noise include quantum noise, TV camera electronic noise, quantization noise from the analog-to-digital converter, time jitter, structure noise in the image intensifier, and video recorder electronic noise. A new noise source was identified, which results from the interplay of fixed pattern noise and the lack of image registration. This type of noise may result from image-intensifier structure noise in combination with TV camera time jitter or recorder time jitter. A similar noise source is generated from the interplay of patient absorption inhomogeneities and patient motion or image re-registration. Signal-to-noise ratios were measured for a variety of experimental conditions using subtracted digital images. The measured signal-to-noise ratios were found to fluctuate on repeat trials with about a 10% standard deviation. Averaging of video frames was found to reduce the noise level by the expected square root N relation, where N is the number of frames averaged. Image-intensifier structure noise was shown to be a dominant noise source in unsubtracted images at medium to high radiation exposure levels. A total-system signal-to-noise ratio (SNR) of 750:1 was measured for an input exposure of 1 mR/frame at the image intensifier input. The effect of scattered radiation on subtracted image SNR was found to be greater than previously reported. The detail SNR was found to vary approximately as one plus the scatter degradation factor. Quantization error noise with 8-bit image processors (signal-to-noise ratio of 890:1) was shown to be of increased importance after recent improvements in TV cameras. The results of the analysis are useful both in the design of future digital radiography systems and the selection of optimum clinical techniques. PMID:6364749

Arnold, B A; Scheibe, P O

1984-03-01

31

Noise analysis of a digital radiography system.  

UK PubMed Central (United Kingdom)

The sources of noise in a digital video subtraction angiography system were identified and analyzed. Signal-to-noise ratios of digital radiography systems were measured using the digital image data recorded in the computer. The major sources of noise include quantum noise, TV camera electronic noise, quantization noise from the analog-to-digital converter, time jitter, structure noise in the image intensifier, and video recorder electronic noise. A new noise source was identified, which results from the interplay of fixed pattern noise and the lack of image registration. This type of noise may result from image-intensifier structure noise in combination with TV camera time jitter or recorder time jitter. A similar noise source is generated from the interplay of patient absorption inhomogeneities and patient motion or image re-registration. Signal-to-noise ratios were measured for a variety of experimental conditions using subtracted digital images. The measured signal-to-noise ratios were found to fluctuate on repeat trials with about a 10% standard deviation. Averaging of video frames was found to reduce the noise level by the expected square root N relation, where N is the number of frames averaged. Image-intensifier structure noise was shown to be a dominant noise source in unsubtracted images at medium to high radiation exposure levels. A total-system signal-to-noise ratio (SNR) of 750:1 was measured for an input exposure of 1 mR/frame at the image intensifier input. The effect of scattered radiation on subtracted image SNR was found to be greater than previously reported. The detail SNR was found to vary approximately as one plus the scatter degradation factor. Quantization error noise with 8-bit image processors (signal-to-noise ratio of 890:1) was shown to be of increased importance after recent improvements in TV cameras. The results of the analysis are useful both in the design of future digital radiography systems and the selection of optimum clinical techniques.

Arnold BA; Scheibe PO

1984-03-01

32

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

International Nuclear Information System (INIS)

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

1994-01-01

33

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

2001-01-01

34

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

35

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

36

Computed radiography dose optimization in pediatric patients  

International Nuclear Information System (INIS)

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

2008-01-01

37

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

38

Impeller Metrology for Pipeline Compressors Using Computed Radiography  

International Nuclear Information System (INIS)

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

2006-03-06

39

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.

2011-01-01

40

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

 
 
 
 
41

AEC set-up optimisation with computed radiography imaging  

International Nuclear Information System (INIS)

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

2005-01-01

42

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

43

Modeling the performance characteristics of computed radiography (CR) systems.  

Science.gov (United States)

Computed radiography (CR) using storage phosphors is widely used in digital radiography and mammography. A cascaded linear systems approach wherein several parameter values were estimated using Monte Carlo methods was used to model the image formation process of a single-side read ;;flying spot'' CR system using a granular phosphor. Objective image quality metrics such as modulation transfer function and detective quantum efficiency were determined using this model and show good agreement with published empirical data. A model such as that addressed in this work could allow for improved understanding of the effect of storage phosphor physical properties and CR reader parameters on objective image quality metrics for existing and evolving CR systems. PMID:20199915

Vedantham, Srinivasan; Karellas, Andrew

2010-03-01

44

Modeling the performance characteristics of computed radiography (CR) systems.  

UK PubMed Central (United Kingdom)

Computed radiography (CR) using storage phosphors is widely used in digital radiography and mammography. A cascaded linear systems approach wherein several parameter values were estimated using Monte Carlo methods was used to model the image formation process of a single-side read ;;flying spot'' CR system using a granular phosphor. Objective image quality metrics such as modulation transfer function and detective quantum efficiency were determined using this model and show good agreement with published empirical data. A model such as that addressed in this work could allow for improved understanding of the effect of storage phosphor physical properties and CR reader parameters on objective image quality metrics for existing and evolving CR systems.

Vedantham S; Karellas A

2010-03-01

45

Correlation of the clinical and physical image quality in chest radiography for average adults with a computed radiography imaging system.  

UK PubMed Central (United Kingdom)

Objective: The purpose of this study was to examine the correlation between the quality of visually graded patient (clinical) chest images and a quantitative assessment of chest phantom (physical) images acquired with a computed radiography (CR) imaging system. Methods: The results of a previously published study, in which four experienced image evaluators graded computer-simulated postero-anterior chest images using a visual grading analysis scoring (VGAS) scheme, were used for the clinical image quality measurement. Contrast-to-noise ratio (CNR) and effective dose efficiency (eDE) were used as physical image quality metrics measured in a uniform chest phantom. Although optimal values of these physical metrics for chest radiography were not derived in this work, their correlation with VGAS in images acquired without an antiscatter grid across the diagnostic range of X-ray tube voltages was determined using Pearson's correlation coefficient. Results: Clinical and physical image quality metrics increased with decreasing tube voltage. Statistically significant correlations between VGAS and CNR (R=0.87, p<0.033) and eDE (R=0.77, p<0.008) were observed. Conclusion: Medical physics experts may use the physical image quality metrics described here in quality assurance programmes and optimisation studies with a degree of confidence that they reflect the clinical image quality in chest CR images acquired without an antiscatter grid. Advances in knowledge: A statistically significant correlation has been found between the clinical and physical image quality in CR chest imaging. The results support the value of using CNR and eDE in the evaluation of quality in clinical thorax radiography.

Moore CS; Wood TJ; Beavis AW; Saunderson JR

2013-07-01

46

Reject analysis in direct digital radiography  

Energy Technology Data Exchange (ETDEWEB)

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

Richter Andersen, Eivind; Jorde, Jannike; Taoussi, Nadia; Yaqoob, Sadia Halima (Department of Health Sciences, Buskerud University College, Drammen (Norway)), Email: eivind.richter.andersen@sus.no; Konst, Bente (Vestfold Hospital Trust, Toensberg (Norway)); Seierstad, Therese (Department of Health Sciences, Buskerud University College, Drammen (Norway); Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway))

2012-03-15

47

Combination of multiple pencil-beam imaging to computed storage phosphor radiography  

International Nuclear Information System (INIS)

Computed radiography (CR) with storage phosphors offers a wide dynamic range and improved sensitivity compared to film-screen technology. In this study CR was combined with a prototype multiple pencil-beam (MPB) imaging device which has been shown to be very effective in scatter reduction. The combination was analyzed and compared to the standard technique of grid screening in 2 ways: a free-response ROC (FROC) analysis was first performed followed by a blinded test arrangement for visual analysis of image quality in a series of computed radiography of the lumbar spine by both the MPB and the grid modalities.The results of the FROC study showed a statistically significant (p

1991-01-01

48

Computers in dental radiography: a scenario for the future  

International Nuclear Information System (INIS)

[en] 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

49

Computers in dental radiography: a scenario for the future  

Energy Technology Data Exchange (ETDEWEB)

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.

Webber, R.L.

1985-09-01

50

Detectability of simulated vessels by computed radiography and digital fluorography  

Energy Technology Data Exchange (ETDEWEB)

Phantom studies were carried out to determine the ability to digital subtraction angiography (DSA), using either Fuji computed radiography (CR) or digital fluorography (DF) system, to detect the simulated vessels. The assessment of detectability was based on observer performance techniques. DFDSA was superior to CRDSA. Detectability of CRDSA was influenced by the incident X-ray exposures. Even though it was improved by contrast enhancement, the magnitude of improvement was dependent upon the incident X-ray exposures and vessel size. (N.K.).

Misumi, Wataru; Yoshioka, Senya; Korogi, Yukunori; Takahashi, Mutsumasa (Kumamoto Univ. (Japan). School of Medicine); Higashida, Yoshiharu

1990-05-01

51

Detectability of simulated vessels by computed radiography and digital fluorography  

International Nuclear Information System (INIS)

[en] Phantom studies were carried out to determine the ability to digital subtraction angiography (DSA), using either Fuji computed radiography (CR) or digital fluorography (DF) system, to detect the simulated vessels. The assessment of detectability was based on observer performance techniques. DFDSA was superior to CRDSA. Detectability of CRDSA was influenced by the incident X-ray exposures. Even though it was improved by contrast enhancement, the magnitude of improvement was dependent upon the incident X-ray exposures and vessel size. (N.K.)

1990-01-01

52

High resolution digital radiography and three-dimensional computed tomography  

Energy Technology Data Exchange (ETDEWEB)

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

Bueno, C.; Barker, M.D. [Lockheed Missiles and Space Co., Inc., Palo Alto, CA (United States). Research and Development Div.

1993-12-31

53

An experimental comparison of detector performance for computed radiography systems.  

Science.gov (United States)

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, 7.74 x 10(-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. PMID:11991117

Samei, Ehsan; Flynn, Michael J

2002-04-01

54

An experimental comparison of detector performance for computed radiography systems.  

UK PubMed Central (United Kingdom)

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, 7.74 x 10(-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.

Samei E; Flynn MJ

2002-04-01

55

A computed tomography implementation of multiple-image radiography  

International Nuclear Information System (INIS)

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

2006-01-01

56

Magnetic resonance imaging and computed radiography in Achilles tendon rupture  

International Nuclear Information System (INIS)

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

1988-01-01

57

Magnetic resonance imaging and computed radiography in Achilles tendon rupture  

Energy Technology Data Exchange (ETDEWEB)

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

Korenaga, Tateo; Hachiya, Junichi; Miyasaka, Yasuo and others

1988-11-01

58

Industrial radiography with Ir-192 using computed radiographic technique  

International Nuclear Information System (INIS)

[en] 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

2003-01-01

59

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

60

Conventional radiography and computed tomography of cardiac assist devices.  

Science.gov (United States)

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. PMID:19408002

Scheffel, Hans; Stolzmann, Paul; Wilhelm, Markus J; Lachat, Mario; Desbiolles, Lotus; Leschka, Sebastian; Frauenfelder, Thomas; Schertler, Thomas; Marincek, Borut; Alkadhi, Hatem

2009-05-01

 
 
 
 
61

Conventional radiography and computed tomography of cardiac assist devices  

International Nuclear Information System (INIS)

[en] 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.)

2009-01-01

62

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

63

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

International Nuclear Information System (INIS)

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

2009-01-01

64

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

65

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

66

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

International Nuclear Information System (INIS)

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

2006-01-01

67

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

68

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

69

Nuclear imaging using Fuji Computed Radiography. The second report  

Energy Technology Data Exchange (ETDEWEB)

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

Yodono, Hiraku; Tarusawa, Nobuko; Katto, Keiichi; Miyakawa, Takayoshi; Watanabe, Sadao; Shinozaki, Tatsuyo

1988-02-01

70

[Bedside chest radiography and optimization of radiographic conditions in the NICU with the Fuji Computed Radiography System].  

UK PubMed Central (United Kingdom)

We devised an application that uses the "Maximum value reading method (AutoIV)" for bedside chest radiography in a neonatal intensive care unit (NICU) that used the Fuji Computed Radiography (FCR) System. The application, named AutoIV-N, uses the relationship for density correction between radiographic conditions (mAs) and the Display Parameter (GS). GS=f (mAs) can be considered the relationship that connects FCR and the X-ray generator. When AutoIV-N is used, radiographic image contrast does not change. Further, radiographic image density fluctuation can be eliminated by random elements such as X-ray output fluctuation of the X-ray generator and the decline of photo-stimulated luminescence caused by fading of the imaging plate. Accordingly, image recording that is suitable for follow-up chest radiography is made possible. We choose nine patients and performed a comparison of radiographic density fluctuation in AutoIV-N and Fix. AutoIV-N was found to be more stable than Fix. It is possible to use the radiographic imaging condition that is optimized for all patients in the NICU by AutoIV-N. This facilitates radiation exposure optimization in medicine. (Article in Japanese).

Tani S; Tanabe C; Abe S; Mihara K

2008-01-01

71

Daily quality control in computed radiography mammography using the manufacturer phantom  

International Nuclear Information System (INIS)

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

2011-01-01

72

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

73

Detection of bifid mandibular condyle by panoramic radiography and cone beam computed tomography  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english AIM: To compare panoramic radiography and cone beam computed tomography (CBCT) in the diagnosis of bifid mandibular condyle. METHODS: The sample consisted of 350 individuals who underwent panoramic radiography and CBCT. In the panoramic radiographs and CBCT images, the presence or absence of bifid mandibular condyle was determined. RESULTS: Presence of bifid mandibular condyle was detected in four cases (1.1%). In all cases, the relation of one condylar process to the oth (more) er was mediolateral and history of trauma was reported. None of the individuals had symptoms. In two cases, panoramic radiography did not reveal the presence of bifid mandibular condyle. CONCLUSIONS: Initial screening for bifid mandibular condyle can be performed by panoramic radiography; however, CBCT images can reveal morphological changes and the exact orientation of the condyle heads.

Neves, Frederico Sampaio; Ramírez-Sotelo, Laura Ricardina; Roque-Torres, Gina; Barbosa, Gabriella Lopes Resende; Haiter-Neto, Francisco; Freitas, Deborah Queiroz de

2013-03-01

74

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

International Nuclear Information System (INIS)

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

2011-01-01

75

Digital Detectors: Computed Radiography (CR) for All Radiologists  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Digital techniques in radiology have many advantages for radiologists, radiographers, patients, clinicians and hospital-operators from many perspectives: diagnostic quality, dose reduction, access to old and new images and reports via PACS, HIS and RIS."nRadiologists concentrate more and more on organs and pathology (super) specialties rather than in modalities. Organ based radiology requires the integration of all modalities and has to cover large geographical regions to deliver expertise, as there few top-experts. This is only possible in the digital world of HICT (Health Information and Communication Technology), where digital detectors are the first step in a long chain of informatics."nToday most of the diagnostic imaging modalities (CT, MRI, US, PET,..) used in radiology are digital except plain film imaging. In order to digitize plain x-ray (also called General Radiology) there is choice between Computed Radiography (CR) based upon storage phosphor screens and DR (Digital Radiography) based on "flat or panel" detectors. A large spectrum of applications and price ranges is available on the market."nTechnology: Both CR and DR rely on conversion and storage of x-ray energy in "pixel"-like elements in the detector. These detectors are linear (film is S-curved) and have a enormous dynamic range (1 in 100.000) so no information is lost and they resist over- and under-exposure up to 4 times."n- In CR x-ray energy is stored into the phosphor-crystals and converted into visible light after stimulation by (laser) light which is in turn captured and digitized by an optical system. Pixels (in size between 50 and 150 µm) are one after one stimulated and translated into a digital image of millions of points. "n- In DR systems x-ray energy is converted in 2 or 3 steps into electrical charge that is stored in every pixel of the detector. These charges are digitized row after row to make a digital image. The conversion of the x-rays is done by a "scintillator" or phosphor, known from screens and image amplifiers. There are 2 groups of DR: the first group is amorphous selenium + TFT pixel backplane and the second is a scintillator + TFT pixel backplane. The first directly converts x-ray into charge (2 steps) and the latter first converts x-rays into light and light into charge in a photodiode in each pixel. "nOf course the DR technology is complex and difficult to manufacture in the large formats needed in radiology (14"x17") and explains the high price/unit (>200 k$)."nDR can only be justified in a limited number of situations: high throughput (like chest), high labor-cost and lack of radiographers, radiation-dose regulations."nThe technical nature of DR is very sensitive to environmental conditions like vibrations (mobile applications) and temperature (Selenium has to be air-conditioned) and the portable models are still bulky and costly to put under the bed patients. However, in the future DR prices are expected to come down"n- There are numerous combined systems: lens or fiber coupled CCD systems guiding the x-ray image into a small (and cheap) CCD with a bad image quality."nSlit/slot methods moving a small bundle of x-rays and a line-detector over the patient during several seconds exhausting the tube and the patient...."nThere is no perfect system: most have some advantages and some drawbacks and all of them are compromises between quality and price. "nConclusion: Today CR based on powder phosphors is still the best solution in a starter situation where cost and a broad range of ap-plications are important, because it replaces all types of film-screen cassettes by 1 CR cassette, without changes to the x-ray modality and the workflow. Immediately it allows lower doses and a decrease in repeat rates to <1% at a high image quality (with multi-frequency image processing like Agfa Musica)."nCR readers are offered in a wide range of sophistication and prices matching most of the need

Frans Dhaenens

2007-01-01

76

PyRAT - python radiography analysis tool (u)  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-01-14

77

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

78

The clinical application of computed radiography in bedside photography of newborn  

International Nuclear Information System (INIS)

[en] 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)

2005-01-01

79

Human performance analysis of industrial radiography radiation exposure events  

Energy Technology Data Exchange (ETDEWEB)

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

Reece, W.J.; Hill, S.G.

1995-12-01

80

Dual-energy phosphor cassette for computed radiography  

International Nuclear Information System (INIS)

A dual-energy imaging technique has been developed for selective material radiography of bone and soft tissue. The essential elements include a gadolinium prefilter, a stack of image-recording stimulable phosphor plates in a single cassette that detect images of progressively higher energy, image-driven scatter and beam-hardening corrections, an automatic registration routine for correcting misalignments between imaging plants, and a noise-reduction algorithm recently reported by Kalender. All processing stages have been implemented on a Pixar image processor. Dual-energy spectral studies aimed at system optimization, algorithm details, and preliminary clinical images will be presented.

1988-12-02

 
 
 
 
81

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-02-15

82

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.

2010-01-01

83

Computed radiography in scoliosis. Diagnostic information and radiation dose  

Energy Technology Data Exchange (ETDEWEB)

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

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

1995-07-01

84

[Digital radiography of the thorax  

UK PubMed Central (United Kingdom)

Digital radiography of the thorax can, now be substituted to conventional chest radiography. Computed radiography with phosphor plates and the new selenium detector are emphasized. The major image processing are explained. Successively the main other methods of digital radiography are described: scanning equalization radiography, laser-digitized radiography and multiwire proportional chambers. Then the advantages and the drawbacks of chest computed radiography are extensively reviewed.

Frija J; de Kerviler E; Zagdanski AM; Feger C; Attal P; Laval-Jeantet M

1997-03-01

85

[Digital radiography of the thorax].  

Science.gov (United States)

Digital radiography of the thorax can, now be substituted to conventional chest radiography. Computed radiography with phosphor plates and the new selenium detector are emphasized. The major image processing are explained. Successively the main other methods of digital radiography are described: scanning equalization radiography, laser-digitized radiography and multiwire proportional chambers. Then the advantages and the drawbacks of chest computed radiography are extensively reviewed. PMID:9113146

Frija, J; de Kerviler, E; Zagdanski, A M; Feger, C; Attal, P; Laval-Jeantet, M

1997-03-01

86

Accuracy of radiography, computed tomography and magnetic resonance imaging in diagnosing foreign bodies in the foot.  

UK PubMed Central (United Kingdom)

PURPOSE: The purpose of this study was to determine the accuracy of conventional radiography, computed tomography (CT) and magnetic resonance imaging (MRI) in detecting foreign bodies by using cadaver feet. MATERIALS AND METHODS: One hundred and sixty foreign bodies consisting of 5 × 2-mm fresh wood, dry wood, glass, porcelain and plastic fragments were randomly placed in the plantar soft tissue of the forefoot and sole. An additional 160 incisions were made without the insertion of foreign bodies. Radiographs, CT and MRI scans were assessed in a blinded fashion for the presence of a foreign body. RESULTS: Overall sensitivity and specificity for foreign body detection was 29% and 100% for radiographs, 63% and 98% for CT and 58% and 100% for MRI. The sensitivity of radiography was lower in the forefoot. CT and MRI detection rates depended on the attenuation values of the foreign bodies and on the susceptibility artefact, respectively. CT was superior to MRI in identifying water-rich fresh wood. CONCLUSIONS: Radiography, CT and MRI are highly specific in detecting foreign bodies but sensitivity is poor. The detection rate depends on the type of foreign body for all techniques and on location for radiography. To identify foreign bodies with MRI, pulse sequences should be used to enhance the susceptibility artefact. In water-rich wood, as in chronically retained wood, CT is more accurate than MRI.

Pattamapaspong N; Srisuwan T; Sivasomboon C; Nasuto M; Suwannahoy P; Settakorn J; Kraisarin J; Guglielmi G

2013-03-01

87

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

International Nuclear Information System (INIS)

A retrospective study comparing portable chest images generated by a computed radiography system with those generated by conventional film radiogrphy is in process. The computed radiography system uses a photostimulable imaging plate, an A/D converter, and image processor, and an image recorder. More than 200 serial portable examinations were reviewed and only the ''shortest interval'' pairs of images from 40 different patients are being evaluated. Included is a spectrum of neonatal lung disease and both assisted ventilation and postoperative complications. The images are reviewed in a blinded fashion by a pediatric cardiovascular radiologist, a pediatric radiologist, two neonatologists, and a neonatal nurse practitioner. The following parameters are assessed: image quality and resolution visualization of normal structures, radiation dosimetry, and diagnostic accuracy

1987-12-04

88

Fine tuning of work practices of common radiological investigations performed using computed radiography system  

Energy Technology Data Exchange (ETDEWEB)

Introduction: The advent of the computed radiography (CR) has brought about remarkable changes in the field of diagnostic radiology. A relatively large cross-section of the human population is exposed to ionizing radiation on account of common radiological investigations. This study is intended to audit radiation doses imparted to patients during common radiological investigations involving the use of CR systems. Method: The entrance surface doses (ESD) were measured using thermoluminescent dosimeters (TLD) for various radiological investigations performed using the computed radiography (CR) systems. Optimization of radiographic techniques and radiation doses was done by fine tuning the work practices. Results and conclusion: Reduction of radiation doses as high as 47% was achieved during certain investigations with the use of optimized exposure factors and fine-tuned work practices.

Livingstone, Roshan S. [Department of Radiology, Christian Medical College, Vellore 632004, Tamil Nadu (India); Timothy Peace, B.S. [Department of Radiology, Christian Medical College, Vellore 632004, Tamil Nadu (India); Sunny, S. [Department of Radiology, Christian Medical College, Vellore 632004, Tamil Nadu (India); Victor Raj, D. [Department of Radiology, Christian Medical College, Vellore 632004, Tamil Nadu (India)]. E-mail: victor45@vsnl.com

2007-05-15

89

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

International Nuclear Information System (INIS)

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

2005-01-01

90

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)

2000-01-01

91

Accuracy of cone-beam computed tomography and periapical radiography in detecting small periapical lesions.  

UK PubMed Central (United Kingdom)

INTRODUCTION: The aim of this study was to determine the diagnostic accuracy of 2 cone-beam computed tomography (CBCT) machines and periapical (PA) radiography in detecting simulated apical lesions created with the smallest dental burs available. METHODS: By using mandibles from human cadavers, simulated apical lesions were created and then progressively enlarged in 16 roots by using sizes #1/4, #1/2, #1, #2, #4, and #6 round burs. Imaging was obtained after each enlargement with a Kodak 9000 3D (Kodak) CBCT, a Veraviewpocs 3De (Morita) CBCT, and intraoral digital PA radiography. Specificity and sensitivity at variable decision thresholds were calculated and plotted on receiver operator characteristic curves. The area under the curve (AUC) served as an estimate of diagnostic accuracy. RESULTS: The overall AUCs for Kodak, Morita, and PA radiography were 0.767 (95% confidence interval [CI], 0.743-0.792), 0.753 (95% CI, 0.728-0.779), and 0.584 (95% CI, 0.554-0.615), respectively. The AUCs for Kodak and Morita were both statistically significantly larger than the AUC for all corresponding simulated lesion sizes imaged with PA radiography. Between Kodak and Morita, there were no statistically significant differences in AUCs for any of the corresponding simulated lesion sizes. CONCLUSIONS: Both CBCT devices demonstrated poor accuracy in detecting simulated lesions smaller than 0.8 mm in diameter, fair to good accuracy when simulated lesion diameter was between 0.8-1.4 mm, and excellent accuracy when simulated lesions were larger than 1.4 mm in diameter. PA radiography, at best, demonstrated poor diagnostic accuracy for all simulated lesion sizes.

Tsai P; Torabinejad M; Rice D; Azevedo B

2012-07-01

92

Effect of multiscale processing in digital chest radiography on automated detection of lung nodule with a computer assistance system.  

Science.gov (United States)

The aim of this study is to evaluate the effect of multiscale processing in digital chest radiography on automated detection of lung nodule with a computer-aided diagnosis (CAD) system. The study involved 58 small-nodule patient cases and 58 normal cases. The 58 patient cases included a total of 64 noncalcified lung nodules up to 15 mm in diameter. Each case underwent an examination with a digital radiography system (Digital Diagnost, Philips Medical Systems), and the acquired image was processed by the following three types of multiscale processing (Unique Image Processing Package, Philips Medical Systems) respectively: (1) standard image from the default processing parameter (structure preference, 0.0), (2) high-pass image with structure preference of 0.4, (3) low-pass image with structure preference of -0.4. The CAD output images were produced with a real-time computer assistance system (IQQAtrade mark-Chest, EDDA Technology). Two experienced chest radiologists established the nodule gold standard by consensus reading according to computed tomography results, and analyzed and recorded the detection of lung nodules and false-positive detections of these CAD output images. For the entire cases involved (each case with three types of different processing), a total of 348 observations were evaluated by the receiver operating characteristic (ROC) analysis. The mean area under the ROC curve (A ( z )) value was 0.700 for the standard images, 0.587 for the high-pass images, and 0.783 for the low-pass images. There were statistically significant A (z) values among these three types of processed images (p < 0.01). Multiscale processing in digital chest radiography can affect the automated detection of lung nodule by CAD, which is consistent with effects from visual inspection. PMID:18239963

He, Qian; He, Wen; Wang, Keyang; Ma, Daqing

2008-02-01

93

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

Energy Technology Data Exchange (ETDEWEB)

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

Li, S. [Shinshu Univ. School of Medicine, Dept. of Radiology, Matsumoto (Japan); Sone, S. [Shinshu Univ. School of Medicine, Dept. of Radiology, Matsumoto (Japan); Kiyono, K. [Shinshu Univ. School of Medicine, Dept. of Radiology, Matsumoto (Japan)

1997-01-01

94

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

International Nuclear Information System (INIS)

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

1999-01-01

95

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

UK PubMed Central (United Kingdom)

In this study, diagnostic reference levels (DRLs) were suggested and patient doses were analysed through the dose-area product value in dental radiography. In intraoral radiography, at three sites, i.e. molar, premolar and incisor on the maxilla and acquired third quartile values: 55.5, 46 and 36.5 mGy cm(2), respectively, were measured. In panoramic, cephalometric and cone beam computed tomography, the values were 120.3, 146 and 3203 mGy cm(2) (16 × 18 cm), respectively. It has been shown that, in intraoral radiography, the patient dose changes proportionally to the value of mA s, but the change in extraoral radiography in response to mA s could not be confirmed. The authors could confirm, however, the difference in dose according to the manufacturer in all dental radiography examinations, except for panoramic radiography. Depending on the size of hospital, there were some differences in patient dose in intraoral radiography, but no difference in patient dose in extraoral radiography.

Han S; Lee B; Shin G; Choi J; Kim J; Park C; Park H; Lee K; Kim Y

2012-07-01

96

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

UK PubMed Central (United Kingdom)

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

Lim CK; Saulez MN; Viljoen A; Carstens A

2013-01-01

97

Differentiating lung abscess and empyema: radiography and computed tomography  

International Nuclear Information System (INIS)

[en] 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

98

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

99

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

Energy Technology Data Exchange (ETDEWEB)

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

Abe, Katsumi; Katsuragawa, Shigehiko; Yanagisawa, Toru (Iwate Medical Univ., Morioka (Japan). School of Medicine); Doi, Kunio

1994-03-01

100

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

International Nuclear Information System (INIS)

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

2002-01-01

 
 
 
 
101

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)

2006-01-01

102

Observer training for computer-aided detection of pulmonary nodules in chest radiography.  

UK PubMed Central (United Kingdom)

OBJECTIVES: To assess whether short-term feedback helps readers to increase their performance using computer-aided detection (CAD) for nodule detection in chest radiography. METHODS: The 140 CXRs (56 with a solitary CT-proven nodules and 84 negative controls) were divided into four subsets of 35; each were read in a different order by six readers. Lesion presence, location and diagnostic confidence were scored without and with CAD (IQQA-Chest, EDDA Technology) as second reader. Readers received individual feedback after each subset. Sensitivity, specificity and area under the receiver-operating characteristics curve (AUC) were calculated for readings with and without CAD with respect to change over time and impact of CAD. RESULTS: CAD stand-alone sensitivity was 59 % with 1.9 false-positives per image. Mean AUC slightly increased over time with and without CAD (0.78 vs. 0.84 with and 0.76 vs. 0.82 without CAD) but differences did not reach significance. The sensitivity increased (65 % vs. 70 % and 66 % vs. 70 %) and specificity decreased over time (79 % vs. 74 % and 80 % vs. 77 %) but no significant impact of CAD was found. CONCLUSION: Short-term feedback does not increase the ability of readers to differentiate true- from false-positive candidate lesions and to use CAD more effectively. KEY POINTS: • Computer-aided detection (CAD) is increasingly used as an adjunct for many radiological techniques. • Short-term feedback does not improve reader performance with CAD in chest radiography. • Differentiation between true- and false-positive CAD for low conspicious possible lesions proves difficult. • CAD can potentially increase reader performance for nodule detection in chest radiography.

De Boo DW; van Hoorn F; van Schuppen J; Schijf L; Scheerder MJ; Freling NJ; Mets O; Weber M; Schaefer-Prokop CM

2012-08-01

103

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

UK PubMed Central (United Kingdom)

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.

O'Keeffe DS; McLeod RW

2004-08-01

104

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

105

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

106

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

Science.gov (United States)

A two-year-old Thoroughbred colt was presented to the Equine Clinic, Onderstepoort Veterinary Academic Hospital for head trauma after rearing and falling backwards, hitting his head on the ground. Following medical therapy for acute onset neurological impairment secondary to a suspected basilar skull fracture, the horse was anaesthetised and computed tomography of the skull was performed. A diagnosis of a comminuted basilar skull fracture was made and skull radiographs were taken for comparison. The horse was subsequently euthanased owing to the poor prognosis; necropsy findings were compatible with imaging findings. The value and limitation of computed tomography versus radiography for the diagnosis of basilar skull fracture are discussed in this report. PMID:23718726

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

2013-04-19

107

Digital vs conventional radiography: cost and revenue analysis  

Energy Technology Data Exchange (ETDEWEB)

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

Dalla Palma, L.; Cuttin, R.; Rimondini, A. [Istituto di Radiologia dell`Universita di Trieste (Italy); Grisi, G. [Dipartimento di Economia e Tecnica Aziendale dell`Universita di Trieste (Italy)

1999-10-01

108

Direct magnification mammography in combination with computed radiography. First clinical results  

International Nuclear Information System (INIS)

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.)

1997-01-01

109

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 re...

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

110

Evaluation of peripheral vascular disease by intravenous digital subtraction angiography with the Fuji computed radiography (FCR) system  

Energy Technology Data Exchange (ETDEWEB)

Intravenous digital subtraction angiography using Fuji computed radiography system (FCR-DSA) was used to evaluate 57 preoperative patients with clinical manifestations of peripheral vascular disease of lower extremity. With its high contrast resolution and good special resolution, image of FCR-DSA could offer optimal information of vascular abnormality in lower extremity distal to midfoot for the diagnosis and the choice of management.

Maeda, Manabu; Mine, Hiroko; Wakabayashi, Kunio; Yoshida, Tetsuo; Suzuki, Soji

1987-03-01

111

Chest radiography and high resolution computed tomography in the evaluation of workers exposed to silica dust: relation with functional findings.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

OBJECTIVES--To compare the usefulness of high resolution computed tomography (HRCT) with chest radiography (CR) in the diagnosis and assessment of severity of silicosis. METHODS--27 workers exposed to silica underwent CR, HRCT, and pulmonary function tests. Two experienced readers independently eval...

Talini, D; Paggiaro, P L; Falaschi, F; Battolla, L; Carrara, M; Petrozzino, M; Begliomini, E; Bartolozzi, C; Giuntini, C

112

Initial quantitative evaluation of computed radiography in an intensive care unit  

International Nuclear Information System (INIS)

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

1996-01-01

113

The effect of scatter reduction on the signal-to-noise ratio in computed radiography.  

UK PubMed Central (United Kingdom)

Signal-to-noise ratio (SNR) in computed radiography (CR) was assessed by using the computerized image data from storage phosphor radiographs in a modification of the Rose model. A multiple pencil-beam (MPB) imaging device, a conventional 1:12 grid, and an air gap of 90 cm were compared in terms of improvement of the signal-to-noise ratio caused by the reduction of scatter. The MPB device showed better SNRs by a factor of 1.25 compared to the grid and air gap which were approximately equal to each other. This is related to its superiority in scatter control, which has also been shown previously. Air gap screening has not been very popular because of geometrical problems, but in scatter reduction it is still comparable to today's grid technology. The optimization of image information content in CR is briefly discussed.

Miettunen RH; Korhola OA

1991-05-01

114

The effect of scatter reduction on the signal-to-noise ratio in computed radiography  

International Nuclear Information System (INIS)

Signal-to-noise ratio (SNR) in computed radiography (CR) was assessed by using the computerized image data from storage phosphor radiographs in a modification of the Rose model. A multiple pencil-beam (MPB) imaging device, a conventional 1:12 grid, and an air gap of 90 cm were compared in terms of improvement of the SNR caused by the reduction of scatter. The MPB device showed better SNRs by a factor of 1.25 compared to the grid and air gap which were approximately equal to each other. This related to its superiority in scatter control, which has also been showed previously. Air gap screening has not been very popular because of geometrical problems, but in scatter reduction it is still comparable to today's grid technology. The optimization of image information content in CR is briefly discussed. (author). 13 refs.; 3 figs

1991-01-01

115

Evaluation of an image receptor for computed radiography system in mammography  

International Nuclear Information System (INIS)

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

2009-10-02

116

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

Energy Technology Data Exchange (ETDEWEB)

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

Tim Roney; Robert Seifert; Bob Pink; Mike Smith

2011-09-01

117

Optimisation of performance for computed radiography in the West of Scotland.  

UK PubMed Central (United Kingdom)

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

Singh G; Martin CJ; McCurrach A; Phanco G

2013-01-01

118

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

119

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

Energy Technology Data Exchange (ETDEWEB)

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)

Doi, Miwako [Osaka Medical Coll., Takatsuki (Japan)

1998-10-01

120

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

 
 
 
 
121

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

Energy Technology Data Exchange (ETDEWEB)

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

Lee, Kwang Hwi; Kwon, Jong Won; Yoon, Young Cheol; Choi, Sang Hee; Jung, Jee Young; Kim, Ji Hye; Lee, Sang Jun [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

2009-02-15

122

3D analysis of congenital scoliosis due to hemivertebra using biplanar radiography.  

UK PubMed Central (United Kingdom)

INTRODUCTION: This study aims to investigate the use of biplanar radiography for assessing congenital scoliosis due to hemivertebra in 3D. MATERIALS AND METHODS: A reconstruction method was developed to model 3D spines with congenital scoliosis from biplanar radiography. 3D measurements quantifying the global posture, scoliotic deformities and imbalance and describing the shape and pose of the hemivertebra were automatically computed. Five cases of congenital scoliosis were analyzed and the accuracy of the method was evaluated by comparing 3D reconstructions from biplanar radiography with 3D segmentations generated from CT. RESULTS: The mean shape accuracy was 1.8 mm (1.5 mm for the vertebral bodies and pedicles and 2.2 mm for the posterior arches). CONCLUSION: Biplanar radiography can be considered an interesting tool for clinical follow-up of congenital scoliosis as it overcomes some limitations of the analyses based on CT or anteroposterior X-ray: head to feet acquisition, low radiation dose and provides a set of automatically computed postural and morphological parameters in 3D.

Humbert L; Steffen JS; Vialle R; Dubousset J; Vital JM; Skalli W

2013-02-01

123

Validation of an image simulation technique for two computed radiography systems: An application to neonatal imaging  

Energy Technology Data Exchange (ETDEWEB)

Purpose: The purpose of this study is to develop a computer model to simulate the image acquisition for two computed radiography (CR) imaging systems used for neonatal chest imaging: (1) The Agfa ADC Compact, 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). The model was then applied to compare the image quality of the two CR imaging systems. Methods: Monte Carlo techniques were used to simulate the transport of primary and scattered x rays in digital x-ray systems. The output of the Monte Carlo program was an image representing the energy absorbed in the detector material. This image was then modified using physical characteristics of the CR imaging systems to account for the signal intensity variations due to the heel effect along the anode-cathode axis, the spatial resolution characteristics of the imaging system, and the various sources of image noise. The simulation was performed for typical acquisition parameters of neonatal chest x-ray examinations. To evaluate the computer model, the authors compared the threshold-contrast detectability in simulated and experimentally acquired images of a contrast-detail phantom. Threshold-contrast curves were computed using a commercially available scoring program. Results: The threshold-contrast curves of the simulated and experimentally acquired images show good agreement; for the two CR systems, 93% of the threshold diameters calculated from the simulated images fell within the confidence intervals of the threshold diameter calculated from the experimentally assessed images. Moreover, the superiority of needle based CR plates for neonatal imaging was confirmed. Conclusions: The good agreement between simulated and experimental acquired results indicates that the computer model is accurate.

Smans, Kristien; Vandenbroucke, Dirk; Pauwels, Herman; Struelens, Lara; Vanhavere, Filip; Bosmans, Hilde [University Hospitals of Leuven, Leuven 3000, Belgium and SCKCEN, Mol 2400 (Belgium); Agfa-Healthcare N.V., Mortsel 2640 (Belgium); University Hospitals of Leuven, Leuven 3000 (Belgium); SCKCEN, Mol 2400 (Belgium); University Hospitals of Leuven, Leuven 3000 (Belgium)

2010-05-15

124

A method for measuring the dose distribution of the radiotherapy domain using the computed radiography system  

Energy Technology Data Exchange (ETDEWEB)

Knowing the dose distribution in a tissue is as important as being able to measure exposure or absorbed dose in radiotherapy. Therefore, we have developed a measurement method for the dose distribution (CR dosimetry) in the phantom based on the imaging plate (IP) of the computed radiography (CR). The IP was applied for the dose measurement as a dosimeter instead of the film used for film dosimetry. The data from the irradiated IP were processed by a personal computer with 10 bits and were depicted as absorbed dose distributions in the phantom. The image of the dose distribution was obtained from the CR system using the Digital Imaging and Communications in Medicine (DICOM) form. The CR dosimetry is an application of CR system currently employed in medical examinations to dosimetry in radiotherapy. A dose distribution can be easily shown by the Dose Distribution Depiction System we developed this time. Moreover, the measurement method is simpler and a result is obtained more quickly compared with film dosimetry. (author)

Homma, Mitsuhiko; Tabushi, Katsuyoshi; Obata, Yasunori; Tamiya, Tadashi; Koyama, Shuji [Nagoya Univ. (Japan). School of Health Sciences; Ishigaki, Takeo [Nagoya Univ. (Japan). School of Medicine

2002-06-01

125

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

International Nuclear Information System (INIS)

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

1992-01-01

126

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

127

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

128

Influence of readout process on presampled modulation transfer function in computed radiography system  

Science.gov (United States)

In a computed radiography (CR) system, there are a number of different mechanisms that cause blurring. The aim of this study was to analyze intrinsic system factors of CR systems that could affect the modulation transfer function (MTF), such as afterglow during readout and the anti-alias filter before analog to digital converter. Methods and Materials: Mathematical slit and edge images were generated from analytical functions. These images were arranged perpendicularly to the laser scan and the plate scan directions, respectively. The influence of afterglow and the anti-alias filter was simulated by using Microsoft Excel. The MTF values calculated from those simulation images were compared with the theoretical MTF values obtained analytically. Results: MTF values in the laser scan direction measured with the slit and edge methods were significantly lower than MTF values in the plate scan direction. The degree of influence on MTF with respect to afterglow and the anti-alias filters was different depending on the measurement method and the scan directions of CR systems. The influence of the anti-alias filters mainly contributed to the differences between MTF values with the slit and edge methods in the laser scan direction.

Kawaji, Yasuyuki; Toyofuku, Fukai; Ideguchi, Tadamitsu; Higashida, Yoshiharu

2012-11-01

129

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

Energy Technology Data Exchange (ETDEWEB)

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 {micro}m 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 {micro}m. 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 {micro}m 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 {micro}m 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.

Smith, C.R.; Erker, J.W. [Bio-Imaging Research, Inc., Lincolnshire, IL (United States)

1993-12-31

130

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.

1993-01-01

131

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

132

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

International Nuclear Information System (INIS)

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

1990-01-01

133

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

134

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)

2010-01-01

135

Comparison of computed radiography and film/screen combination using a contrast-detail phantom.  

UK PubMed Central (United Kingdom)

The purpose of this work is to compare computed radiography (Kodak CR 400) and film/screen combination (Speed 400) systems in regards of patient dose, technique settings, and contrast-detail detectability. A special contrast-detail phantom with drilled holes of varying diameter (detail) and varying depth (contrast) was utilized. Various thicknesses of the Lucite sheets were utilized to simulate scattering tissues. Images of the phantom were acquired using a range of 60-120 kVp for film/screen and CR with a conventional x-ray tube and then for CR with additional 2 mm aluminum added filtration to the x-ray beam. The patient entrance skin dose was measured while maintaining 1.6 o.d. for film/screen images and 1900 Exposure Index for CR images. CR phantom images were displayed on the diagnostic workstation for soft copy reading as well as printed on films for hard copy reading on viewbox. Four physicists evaluated the images by scoring the threshold target depth along the row of the same target diameter. Detection ratio was calculated by counting the number of detectable targets divided by the total number of targets in the phantom. The overall score was related to the patient entrance skin dose, kVp, and the thickness of the scattering material. The patient entrance skin dose was reduced as the additional aluminum filter was added to the x-ray beam. Our findings suggested using a higher kVp setting and additional added filtration would reduce the patient entrance skin dose without compromising the contrast-detail detectability, which was compensated by the contrast manipulation on soft-copy display workstations.

Lu ZF; Nickoloff EL; So JC; Dutta AK

2003-01-01

136

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

International Nuclear Information System (INIS)

[en] 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.

2010-01-01

137

Computed tomographic analysis of urinary calculi  

International Nuclear Information System (INIS)

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

1984-01-01

138

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

139

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2003-12-01

140

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

2003-01-01

 
 
 
 
141

Analysis of cylindrical boron carbide-alumina pellets by neutron radiography technique  

International Nuclear Information System (INIS)

In the present work the boron carbide-alumina sintered pellets chemical composition and physical changes was investigated by the neutron radiography techniques. The green pellets obtained by composition in the 300MPa pressure was then sintered in temperatures and times varying between 1500 to 1700 deg C and 1 to 3 hours, respectively. The mass loss of the pellets determination was carried out, and the results was related to that obtained by micrographs and X-ray analysis patterns examination. A relevant contribution to this search was brought by the neutron radiography. Boron neutron absorbance was utilized to verifying the hypothesis of your depletion of the system, in very severe conditions of sintering. (author)

1996-11-01

142

Improved computed radiography image quality from a BaFl:Eu photostimulable phosphor plate.  

Science.gov (United States)

Recent advances in the design of photostimulable phosphor (PSP) plates for computed radiography (CR) systems have made it possible to manufacture plates made of BaFI:Eu phosphor material in the cassette form. The image quality of this plate, six BaF(Br,I):Eu plates, and one BaFBr:Eu plate were evaluated in terms of presampling modulation transfer function (MTF), normalized Wiener spectra (WSN), and detective quantum efficiency (DQE). Compared with the best-performing BaF(Br,I):Eu plate, the BaFI:Eu plate provided DQE that was higher, at spatial frequencies of 0.5, 1.0, and 2.0 cycles/mm, by 12% (21.8 versus 19.4), 13% (18.8 versus 16.7), and 11% (12.0 versus 10.8), respectively. Since presampling MTF values of the two plates were comparable, the BaFI:Eu plate's higher DQE is attributable to total WSN conversely being lower by 17% [8.65 x 10(-5) (mm2) versus 10.38 x 10(-5) (mm2)], 17% [5.85 x 10(-5) (mm2) versus 7.03 x 10(-5) (mm2)], and 12% [2.82 x 10(-5) (mm2) versus 3.19 x 10(-5) (mm2)] at the specified frequencies, respectively, primarily due to the contribution of x-ray quantum WSN. This jibes with the high x-ray absorption provided by the 27%-higher x-ray attenuation coefficients (7.54 versus 6.07, at 60 KeV) that BaFI offers over BaF(Br(0.85),I(0.15)), a result of the high atomic number of BaFI's exclusively iodine halide content. The results were consistent with earlier studies of several of these same plates and indicate that BaFI:Eu is a promising avenue to lower image noise and higher overall CR system image quality. PMID:11991131

Nakano, Yasushi; Gido, Tomonori; Honda, Satoshi; Maezawa, Akihiro; Wakamatsu, Hideaki; Yanagita, Takafumi

2002-04-01

143

Improved computed radiography image quality from a BaFl:Eu photostimulable phosphor plate.  

UK PubMed Central (United Kingdom)

Recent advances in the design of photostimulable phosphor (PSP) plates for computed radiography (CR) systems have made it possible to manufacture plates made of BaFI:Eu phosphor material in the cassette form. The image quality of this plate, six BaF(Br,I):Eu plates, and one BaFBr:Eu plate were evaluated in terms of presampling modulation transfer function (MTF), normalized Wiener spectra (WSN), and detective quantum efficiency (DQE). Compared with the best-performing BaF(Br,I):Eu plate, the BaFI:Eu plate provided DQE that was higher, at spatial frequencies of 0.5, 1.0, and 2.0 cycles/mm, by 12% (21.8 versus 19.4), 13% (18.8 versus 16.7), and 11% (12.0 versus 10.8), respectively. Since presampling MTF values of the two plates were comparable, the BaFI:Eu plate's higher DQE is attributable to total WSN conversely being lower by 17% [8.65 x 10(-5) (mm2) versus 10.38 x 10(-5) (mm2)], 17% [5.85 x 10(-5) (mm2) versus 7.03 x 10(-5) (mm2)], and 12% [2.82 x 10(-5) (mm2) versus 3.19 x 10(-5) (mm2)] at the specified frequencies, respectively, primarily due to the contribution of x-ray quantum WSN. This jibes with the high x-ray absorption provided by the 27%-higher x-ray attenuation coefficients (7.54 versus 6.07, at 60 KeV) that BaFI offers over BaF(Br(0.85),I(0.15)), a result of the high atomic number of BaFI's exclusively iodine halide content. The results were consistent with earlier studies of several of these same plates and indicate that BaFI:Eu is a promising avenue to lower image noise and higher overall CR system image quality.

Nakano Y; Gido T; Honda S; Maezawa A; Wakamatsu H; Yanagita T

2002-04-01

144

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

145

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

International Nuclear Information System (INIS)

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

2006-01-01

146

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.).

1990-01-01

147

Malignant bone tumors of the pelvis and of the extremities. Conventional radiography, arteriography and computed tomography  

Energy Technology Data Exchange (ETDEWEB)

Bone tumors of the extremities are usually diagnosed by conventional radiography. A good angiogram may render information not only about intra- and extraosseous extension of the tumor, but often also about the biological dignity. CT is usually not necessary, especially since it is sometimes difficult to define the extraosseous borders of these extremity tumors with this method. In bone tumors of the pelvis, however, neither conventional radiography nor angiography render reliable information about the extent of the tumor, which CT is very well able to do. Therefore CT is primarily indicated for evaluation of bone tumors in this region. Angiography is done only for preoperative evaluation of the vascular architecture or for potential therapeutic embolisation.

Gullotta, U.; Reiser, M.; Feuerbach, S.; Biehl, T.

1981-01-01

148

A quality control program for the computed radiography images transmitted to the emergency departments image review-workstation  

International Nuclear Information System (INIS)

[en] Computed Radiography images are currently being processed by the use of the Agfa Diagnostic Centre (ADC) at the Royal Prince Alfred Hospital. The ADC makes use of a filmless cassette, which has a re-usable intensifying screen with photostimulable storage phosphors that retain a latent image. The 8-bit image is then transmitted via an ADC-IMPAX system to the Image Review Monitors in the Emergency Department. A Quality Control program has been established to monitor and detect the performance levels of the computed radiographic image information transmitted to the Emergency Departments remote review workstation. The goals of this exercise were to first identify problems and their frequency that would affect the quality of the information transmitted. Common errors that affected the quality of transmitted information were: entire and complete examinations not being transmitted, incorrect image orientation and the lack of side markers, duplicate images and the incorrect use of image processing algorithms. Once the problems are identified and addressed, the Quality Control program should identify any changes to the performance level in the quality of image information that is being transmitted to the Emergency Department. Copyright (1997) Australian Institute of Radiography

1997-01-01

149

Building and using a data base to identify parameters to further improve diagnostic performance on the Toshiba computed radiography system Model 201  

International Nuclear Information System (INIS)

[en] The digital imaging group at the University of Arizona Health Sciences Center Radiology Department is vigorously pursuing the development of a total digital radiology department (TDRD). One avenue of research being conducted is to define the needed resolutions and capabilities of TDRD systems. Parts of that effort are described in these proceedings and elsewhere. One of these investigations is to assess the general application of computed radiography (CR) in clinical imaging. Specifically the authors are comparing images produced by the Toshiba computed radiography system (Model 201) to those produced by conventional imaging techniques. This paper describes one aspect of that work

1987-01-01

150

Neutron radiography  

Energy Technology Data Exchange (ETDEWEB)

Neutron radiography is a well-known inspection technique for nondestructive testing of a variety of materials. The basis principles of neutron radiography are presented along with a discussion of neutron radiographic techniques and beam energy and collimation. The neutron radiography unit at Tun Ismail Atomic Research Center (PUSPATI) is described, and applications of neutron radiography in nondestructive testing in nuclear and non-nuclear areas are noted.

Abas, M.A.B.

1981-01-01

151

PyRAT (python radiography analysis tool): overview  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-01-14

152

A method to produce and validate a digitally reconstructed radiograph-based computer simulation for optimisation of chest radiographs acquired with a computed radiography imaging system.  

UK PubMed Central (United Kingdom)

OBJECTIVES: The purpose of this study was to develop and validate a computer model to produce realistic simulated computed radiography (CR) chest images using CT data sets of real patients. METHODS: Anatomical noise, which is the limiting factor in determining pathology in chest radiography, is realistically simulated by the CT data, and frequency-dependent noise has been added post-digitally reconstructed radiograph (DRR) generation to simulate exposure reduction. Realistic scatter and scatter fractions were measured in images of a chest phantom acquired on the CR system simulated by the computer model and added post-DRR calculation. RESULTS: The model has been validated with a phantom and patients and shown to provide predictions of signal-to-noise ratios (SNRs), tissue-to-rib ratios (TRRs: a measure of soft tissue pixel value to that of rib) and pixel value histograms that lie within the range of values measured with patients and the phantom. The maximum difference in measured SNR to that calculated was 10%. TRR values differed by a maximum of 1.3%. CONCLUSION: Experienced image evaluators have responded positively to the DRR images, are satisfied they contain adequate anatomical features and have deemed them clinically acceptable. Therefore, the computer model can be used by image evaluators to grade chest images presented at different tube potentials and doses in order to optimise image quality and patient dose for clinical CR chest radiographs without the need for repeat patient exposures.

Moore CS; Liney GP; Beavis AW; Saunderson JR

2011-10-01

153

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

International Nuclear Information System (INIS)

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

2005-01-01

154

Comparison of patient dose from imaging protocols for dental implant planning using conventional radiography and computed tomography.  

UK PubMed Central (United Kingdom)

OBJECTIVES: To compare the radiation doses from imaging protocols for dental implant planning either using conventional radiography only (dental panoramic radiography (DPR), cephalometry and linear cross-sectional tomography) or involving computed tomography (CT). METHODS: Organ absorbed doses were measured using a female Rando anthropomorphic phantom loaded with lithium fluoride thermoluminescent dosemeters (TLD). Standard mandibular protocols for dental implant planning were followed using either a conventional dental radiographic unit (PM 2002 CC Planmeca, Helsinki, Finland) or CT scanner (Excel Twin Elscint, Haifa, Israel). Organ absorbed and effective doses were calculated. Effective dose was calculated using two approaches, one based on the ICRP method which excludes the salivary tissue from the remainder organs (designated E(exc)), and the other with its inclusion (E(inc)). RESULTS: The greatest individual organ doses for any examination were measured in the salivary tissue. E(exc) for panoramic, cephalometric and cross-sectional tomography using DPR was 0.004 mSv, 0.002 mSv and 0.002 mSv, respectively, whereas with CT it was 0.314 mSv. The value of E(inc) calculated using these data was between two and five times E(exc). CONCLUSIONS: E(inc) greatly increases the apparent radiation burden, especially with high dose procedures. CT techniques can provide excellent images, but at the cost of increased radiation detriment. DPR with a cross-sectional tomography facility may give adequate clinical information at a greatly reduced dose.

Lecomber AR; Yoneyama Y; Lovelock DJ; Hosoi T; Adams AM

2001-09-01

155

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).

1993-01-01

156

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

Science.gov (United States)

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 approximately 20 mAs compared with approximately 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% (sigma=2.5%), far less than the -16.6% to +9.3% (sigma=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. PMID:12906194

Rong, Xiujiang J; Krugh, Kerry T; Shepard, S Jeff; Geiser, William R

2003-07-01

157

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

158

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

1995-01-01

159

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

UK PubMed Central (United Kingdom)

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.

Muhogora W; Padovani R; Bonutti F; Msaki P; Kazema R

2011-07-01

160

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

 
 
 
 
161

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

162

Study of cassette system for linacography using computed radiography. Application of a heavy metallic sheet to the metallic plate  

International Nuclear Information System (INIS)

The selection of a suitable intensifying metallic plate is an important problem in improving the quality of images of linacography (LG) using computed radiography (CR). We examined a heavy metallic sheet (HMS: Sumitomo Electronic Engineering CO. Inc.) and copper (Cu) plate as devices for the intensification and elimination of scattered x-rays by comparing the quality of CR images. Results showed that the HMS had better selectivity, a higher contrast improvement factor and greater removal of scattered x-rays than the copper plate because of its high linear attenuation coefficient. It was also shown that, because of the flexibility and elasticity of the HMS, it could be in closer contact with the imaging plate (IP) without causing damage. To increase the sharpness of CR images, the HMS should be used instead of a copper plate, and it should be used with the cassette developed by Sato et al. (1997). (author)

1999-01-01

163

Study of cassette system for linacography using computed radiography. Application of a heavy metallic sheet to the metallic plate  

Energy Technology Data Exchange (ETDEWEB)

The selection of a suitable intensifying metallic plate is an important problem in improving the quality of images of linacography (LG) using computed radiography (CR). We examined a heavy metallic sheet (HMS: Sumitomo Electronic Engineering CO. Inc.) and copper (Cu) plate as devices for the intensification and elimination of scattered x-rays by comparing the quality of CR images. Results showed that the HMS had better selectivity, a higher contrast improvement factor and greater removal of scattered x-rays than the copper plate because of its high linear attenuation coefficient. It was also shown that, because of the flexibility and elasticity of the HMS, it could be in closer contact with the imaging plate (IP) without causing damage. To increase the sharpness of CR images, the HMS should be used instead of a copper plate, and it should be used with the cassette developed by Sato et al. (1997). (author)

Sato, Hiroshi [Kohsei Chuo General Hospital, Tokyo (Japan); Yokozawa, Masayuki; Tanaka, Keiichi; Sakai, Hideaki

1999-02-01

164

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

International Nuclear Information System (INIS)

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

2012-01-01

165

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

166

New projects of supermagnifying radiography, 2-K-edge subtraction coronary angiography, and in viro fluorescent analysis with synchrotron radiation  

International Nuclear Information System (INIS)

This paper reports on the design of fluorescent radiography (supermagnifying radiography, K-edge substration radiography with K-edge absorption of two metals and monochromatic x-ray CT) new powerful K-edge subtraction coronary angiography and in vivo fluorescent analysis with synchrotron radiation of Spring 8 (8 GeV). In the first system, a short beam transport of about 30 m and a large rotary target were used. In the second, a long beam transport of about 200 m, a vertical wiggler, a large crystal reflector for expansion of beam size, an x-ray shutter system, and high-definition ITV systems were used; and in the third, non-coplanar radiation systems with a cylindrical detector array similar to that used at radiosurgery were used.

1990-01-01

167

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

168

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

International Nuclear Information System (INIS)

[en] 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

169

Nondestructive inspection of chemical weapons combining neutron activation analysis and neutron radiography techniques  

Energy Technology Data Exchange (ETDEWEB)

A preliminary design for a transportable neutron system has been made for nondestructive detection of weapon materials such as chemical agents or explosives. The system combines imaging and identifying techniques and uses a SODERN 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 performance of neutron radiography and neutron activation analysis. 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 radiations to the operators. The system includes only industrial sub-assemblies, transportable by truck to be used in open areas.

Bach, P.

1994-12-31

170

Flash radiography  

International Nuclear Information System (INIS)

[en] Flash radiography is a technique of radiography that has been used to a limited degree in South Africa, its users being restricted to ballistics and Research and Development in this field. In flash radiography the object being radiographed is by no means static. In flash radiography the object or event being radiographed, is not only obscured, but it is also in motion at very high speeds or very short duration. An image can only be obtained by a very short duration single pulse of x-rays. The main problem encountered with flash radiography was the production of exposures of very short duration and extremely high output. Specialised x-ray equipment was needed for this

1983-01-01

171

Computer Based Power analysis  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this Computer based Power Analysis has focused at building a compact scheme for monitoring the parameters and to protect the generator by replacing the relays into various transducers and are interfaced with the Personal Computer (PC) and the generator protection is implemented by means of a single computer using the time sharing scheme. In Thermal power plants various inter locks and protections are used for safeguarding generator, boiler, turbine, coal feeders etc., Hard-wired logic gates are used in the most of the existing power plants.

Dr.J.RajanCSE,

2012-01-01

172

The scatter-to-primary ratio as a function of varying X-ray absorption measured by computed radiography  

International Nuclear Information System (INIS)

Some scatter studies have previously been conducted using film as a detector. The serious limitations caused by the narrow latitude, the non-linear density response, and the required optical densitometric measurements of film can be avoided by computed radiography which provides linear numeric data over a wide dynamic range. The imaging plate is used as a large-area detector and the data is analyzed from the computer memory. Variation in the scatter-to-primary ratio within an image caused by absorption differences was simulated in a water-aluminium phantom. The measurement technique showed repeatable results, being comparable to the values expected on the basis of previous studies. A multi pencil-beam (MPB) imaging device was also compared to a standard 1:2 grid by this technique. The maximal scatter-to-primary ratio in our model was up to 7.9 with no scatter reduction, 1.5 with grid, and 0.4 with the MPB device. The variation caused by the absorption of primary radiation was much less in the MPB modality, and the MPB system was also less sensitive to an increase in the used tube voltage from 60 to 120 kVp. The benefits of multiple pencil-beam imaging in scatter reduction are briefly discussed. (author). 12 refs.; 2 figs

1991-01-01

173

Computerized detection of pulmonary nodules by single-exposure dual-energy computed radiography of the chest (part 1)  

International Nuclear Information System (INIS)

[en] Objective: To clarify the usefulness of computerized detection of pulmonary nodules (PNs) in single-exposure dual-energy subtraction computed radiography (CR) images of the chest. Methods and material: Our scheme uses bone-subtracted CR (BS-CR) images, and consists of a contrast-adaptive filter for detection of the candidates for PNs and a vessel-enhancing filter for elimination of vessel opacities in the candidates for PNs. For the evaluation, 12 clinical cases with multiple PNs were used, and four radiologists participated in this study. Results: The detectability of our computer-aided diagnosis (CAD) was compared with detectabilities of radiologists. The mean true-positive (TP) number of four radiologists was 1.60±1.03, and that of the CAD was 1.83±1.34. There was no significant difference in the nodule detectabilities between the radiologists and CAD (P=0.18). However, the false-positive (FP) rate of the CAD was 9.42±2.54 per image, whereas the mean FP rate of the radiologists was 1.40±0.64 per image. Conclusion: Computerized detection of PNs is considered to be useful in the determination of radiological diagnoses. However, reducing the number of FP findings remains an important problem to be solved

2002-01-01

174

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

Energy Technology Data Exchange (ETDEWEB)

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

Fickel, T.E.

1988-02-01

175

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

Science.gov (United States)

Radiation doses absorbed by the uterus, ovary, testicle and active bone marrow are computed for cervical, thoracic, lumbar, full spine and chest series performed under typical office conditions. Assuming a nonthreshold, linear relationship between dose and radiogenic effect, the computed tissue-specific doses are used to estimate the probability that each X-ray series might enhance the statistical probability of occurrence of an adult leukemia fatality of the irradiated patient; a childhood leukemia, mental retardation or cancer fatality as a result of fetal irradiation; or a variety of sex cell chromosomal aberrations in irradiated patients. It is concluded that the greatest hazard to active bone marrow, the uterus and the gonads is posed by lumbar and full spine radiography and that the need to adequately justify such exposure is mandatory; furthermore, in these series, irradiation of the ovary is 10 times as great as that of the testicle. Lumbar radiographic examinations can be made significantly safer by the elimination of the lumbosacral spot view. PMID:3351398

Fickel, T E

1988-02-01

176

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

UK PubMed Central (United Kingdom)

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

Fickel TE

1988-02-01

177

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

International Nuclear Information System (INIS)

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

1988-01-01

178

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

179

New double-tracer digital radiography for analysis of spatial and temporal myocardial flow heterogeneity.  

UK PubMed Central (United Kingdom)

A new high-resolution digital radiographic technique based on the deposition of (125)I- and (3)H-labeled desmethylimipramine (IDMI and HDMI, respectively) was developed for the assessment of spatial and temporal myocardial flow heterogeneity at a microvascular level. The density distributions of two tracers, or relative flow distributions, were determined by subtraction digital radiography using two imaging plates of different sensitivity. The regions resolved are comparable in size to vascular regulatory units (400 x 400 microm(2)). This method was applied to the measurement of within-layer myocardial flow distributions in Langendorff-perfused rabbit hearts. The validity of this method was confirmed by the strong correlation between regional densities of two tracers injected simultaneously (r = 0.89 +/- 0.03, n = 8). The temporal flow stability was evaluated by a 90-s continuous IDMI injection and subsequent bolus HDMI injection (n = 8). Regional densities of the two tracers were fairly correlated (r = 0.86 +/- 0.03), indicating that the spatial pattern of flow distribution was stable even at a microvascular level over a 90-s period. The effect of microsphere embolization on the flow distribution was also investigated by the sequential injections of IDMI, 15-microm microspheres, and HDMI at 20-s intervals (n = 8). Microembolization increased the coefficient of variation of tracer density from 19 to 25% (P < 0.05), whereas the regional densities of two tracers were still correlated substantially, as in the case of no embolization (r = 0.84 +/- 0.06). Thus the microsphere embolization enhanced flow heterogeneity with increasing flow differences between control high-flow and control low-flow regions but rather maintained the pattern of flow distribution. In conclusion, double-tracer digital radiography will be a promising method for the spatial and temporal myocardial flow analysis at microvascular levels.

Matsumoto T; Tachibana H; Ogasawara Y; Kajiya F

2001-01-01

180

New double-tracer digital radiography for analysis of spatial and temporal myocardial flow heterogeneity.  

Science.gov (United States)

A new high-resolution digital radiographic technique based on the deposition of (125)I- and (3)H-labeled desmethylimipramine (IDMI and HDMI, respectively) was developed for the assessment of spatial and temporal myocardial flow heterogeneity at a microvascular level. The density distributions of two tracers, or relative flow distributions, were determined by subtraction digital radiography using two imaging plates of different sensitivity. The regions resolved are comparable in size to vascular regulatory units (400 x 400 microm(2)). This method was applied to the measurement of within-layer myocardial flow distributions in Langendorff-perfused rabbit hearts. The validity of this method was confirmed by the strong correlation between regional densities of two tracers injected simultaneously (r = 0.89 +/- 0.03, n = 8). The temporal flow stability was evaluated by a 90-s continuous IDMI injection and subsequent bolus HDMI injection (n = 8). Regional densities of the two tracers were fairly correlated (r = 0.86 +/- 0.03), indicating that the spatial pattern of flow distribution was stable even at a microvascular level over a 90-s period. The effect of microsphere embolization on the flow distribution was also investigated by the sequential injections of IDMI, 15-microm microspheres, and HDMI at 20-s intervals (n = 8). Microembolization increased the coefficient of variation of tracer density from 19 to 25% (P < 0.05), whereas the regional densities of two tracers were still correlated substantially, as in the case of no embolization (r = 0.84 +/- 0.06). Thus the microsphere embolization enhanced flow heterogeneity with increasing flow differences between control high-flow and control low-flow regions but rather maintained the pattern of flow distribution. In conclusion, double-tracer digital radiography will be a promising method for the spatial and temporal myocardial flow analysis at microvascular levels. PMID:11123264

Matsumoto, T; Tachibana, H; Ogasawara, Y; Kajiya, F

2001-01-01

 
 
 
 
181

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

Energy Technology Data Exchange (ETDEWEB)

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

Boyd D. Christensen

2009-05-01

182

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

UK PubMed Central (United Kingdom)

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

Yano Y; Yabuuchi H; Tanaka N; Morishita J; Akasaka T; Matsuo Y; Sunami S; Kamitani T; Jinnouchi M; Yamasaki Y; Nagao M; Sasaki M

2013-07-01

183

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

Science.gov (United States)

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

Yang, Chang-Ying Joseph; Huang, Weidong

2009-02-01

184

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1995-11-01

185

Computational analysis of RNAs.  

UK PubMed Central (United Kingdom)

Genome sequence analysis of RNAs presents special challenges to computational biology, because conserved RNA secondary structure plays a large part in RNA analysis. Algorithms well suited for RNA secondary structure and sequence analysis have been borrowed from computational linguistics. These "stochastic context-free grammar" (SCFG) algorithms have enabled the development of new RNA gene-finding and RNA homology search software. The aim of this paper is to provide an accessible introduction to the strengths and weaknesses of SCFG methods and to describe the state of the art in one particular kind of application: SCFG-based RNA similarity searching. The INFERNAL and RSEARCH programs are capable of identifying distant RNA homologs in a database search by looking for both sequence and secondary structure conservation.

Eddy SR

2006-01-01

186

Computational analysis of RNAs.  

Science.gov (United States)

Genome sequence analysis of RNAs presents special challenges to computational biology, because conserved RNA secondary structure plays a large part in RNA analysis. Algorithms well suited for RNA secondary structure and sequence analysis have been borrowed from computational linguistics. These "stochastic context-free grammar" (SCFG) algorithms have enabled the development of new RNA gene-finding and RNA homology search software. The aim of this paper is to provide an accessible introduction to the strengths and weaknesses of SCFG methods and to describe the state of the art in one particular kind of application: SCFG-based RNA similarity searching. The INFERNAL and RSEARCH programs are capable of identifying distant RNA homologs in a database search by looking for both sequence and secondary structure conservation. PMID:17381287

Eddy, S R

2006-01-01

187

Electron radiography  

Energy Technology Data Exchange (ETDEWEB)

The technique of charged particle radiography has been developed and proved with 800 MeV protons at LANSCE and 24 GeV protons at the AGS. Recent work at Los Alamos National Laboratory in collaboration with the Idaho Accelerator Center has extended this diagnostic technique to electron radiography through the development of an inexpensive and portable electron radiography system. This system has been designed to use 30 MeV electrons to radiograph thin static and dynamic objects. The system consists of a 30 MeV electron linear accelerator coupled to a quadrupole lens magnifier constructed from permanent magnet quadrupoles. The design features and commissioning results of this radiography system are presented.

Merrill, Frank [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87544 (United States)]. E-mail: fmerrill@lanl.gov; Harmon, Frank [Idaho Accelerator Center, Idaho State University, Pocatello, ID 83201 (United States); Hunt, Alan [Idaho Accelerator Center, Idaho State University, Pocatello, ID 83201 (United States); Mariam, Fesseha [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87544 (United States); Morley, Kevin [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87544 (United States); Morris, Christopher [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87544 (United States); Saunders, Alexander [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87544 (United States); Schwartz, Cynthia [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87544 (United States)

2007-08-15

188

Electron radiography  

International Nuclear Information System (INIS)

The technique of charged particle radiography has been developed and proved with 800 MeV protons at LANSCE and 24 GeV protons at the AGS. Recent work at Los Alamos National Laboratory in collaboration with the Idaho Accelerator Center has extended this diagnostic technique to electron radiography through the development of an inexpensive and portable electron radiography system. This system has been designed to use 30 MeV electrons to radiograph thin static and dynamic objects. The system consists of a 30 MeV electron linear accelerator coupled to a quadrupole lens magnifier constructed from permanent magnet quadrupoles. The design features and commissioning results of this radiography system are presented.

2007-01-01

189

Industrial radiography  

International Nuclear Information System (INIS)

This Health and Safety Executive Information Sheet on industrial radiography aims to inform directors and managers of industrial radiography companies on the safety precautions necessary to ensure that their personnel do not exceed dose guidelines for exposure to ionizing radiation. The Ionising Radiations Regulations 1985 (IRR85) require that exposure doses for radiographers are kept as low reasonably practicable. Equipment maintenance, and the employment of proper emergency procedures will help to ensure personnel safety. (UK).

1994-01-01

190

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1993-05-15

191

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.

1993-01-01

192

Broadening the radiography spectrum  

International Nuclear Information System (INIS)

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

2006-05-01

193

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

194

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

Science.gov (United States)

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

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

2013-02-18

195

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

UK PubMed Central (United Kingdom)

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

Poulikakos LD; Sedighi Gilani M; Derome D; Jerjen I; Vontobel P

2013-07-01

196

Computer aided safety analysis  

International Nuclear Information System (INIS)

[en] 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

1988-01-01

197

X-Ray Digital Radiography and Computed Tomography Characterization of Targets  

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-04-16

198

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

Energy Technology Data Exchange (ETDEWEB)

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

Friedman, P.J.; Feigin, D.S.; Liston, S.E.; Alazraki, N.P.; Haghighi, P.; Young, J.A.; Peters, R.M.

1984-10-01

199

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

International Nuclear Information System (INIS)

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

1984-10-01

200

Industrial radiography  

International Nuclear Information System (INIS)

[en] 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

1992-01-01

 
 
 
 
201

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

202

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

International Nuclear Information System (INIS)

[en] 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

2009-01-01

203

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

Energy Technology Data Exchange (ETDEWEB)

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

Kido, Shoji E-mail: kido@ai.csse.yamaguchi-u.ac.jp; Kuriyama, Keiko; Kuroda, Chikazumi; Nakamura, Hironobu; Ito, Wataru; Shimura, Kazuo; Kato, Hisatoyo

2002-12-01

204

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

205

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

Directory of Open Access Journals (Sweden)

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

Alain Pierret; Chris J Moran; Colin B Mclachlan; John M Kirby

2000-01-01

206

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

International Nuclear Information System (INIS)

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

2011-01-01

207

The development of a high-precision microfocus X-ray computed tomography and digital radiography system for industrial applications  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the design and development of a high-precision microfocus X-ray inspection system for ultra-high resolution 3-D computed tomography (CT) and 2-D realtime radiography for a wide range of industries. 3-D CT involves not only acquiring a set of high-resolution 2-D X-ray images, but also demands a comparably high accuracy in the positional alignment of these images when reconstructing the 3-D volume. Although many systems allow the capture of very high resolution 2-D images, the accuracy of any 3-D CT data falls short due to inaccuracies in the relative known positions of source and manipulator. The use of high-brightness, high-resolution X-ray sources (up to 385kV, some using LaB6 cathodes) is covered in detail, together with a description of a range of highresolution detectors optimised for various X-ray energy ranges. Particular attention is paid to the dimensional stability of the system and the accuracy of the sample manipulator, so that the high resolution information present in the radiographic images is not compromised in the reconstruction of the CT volume. For small samples, volumes with resolution down to 5 microns can be obtained with this system, whereas the volume resolution for larger samples is down to 0.1% or 0.03% of the object size, depending on the detector option chosen. The paper will also outline the trade-offs between resolution, sample size, penetration and the speed of both acquisition and reconstruction. A number of real examples will be discussed to illustrate the wide range of applications.

Ramsey, A.T.; Dermody, G.S.; Hadland, R.; Haig, I.G. [X-Tek Systems Ltd., Tring, Herts (United Kingdom)

2003-07-01

208

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.

2007-01-01

209

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)

2004-01-01

210

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-04-01

211

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

2003-01-01

212

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

213

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

214

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-05-01

215

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-05-15

216

Scatter-to-primary ratio and absorption efficiency in screen-film and computed radiography systems.  

UK PubMed Central (United Kingdom)

PURPOSE: To determine whether the scatter-to-primary (s/p) ratio, measured on a screen-film or computed radiographic (CR) system, varies with chemical composition or primary attenuation properties. MATERIALS AND METHODS: The s/p ratios of four Gd2O2S screens, three CaWO4 screens and a CR screen, were determined under uniform irradiation conditions. One simulated low scatter conditions, such as in lung imaging, and the other simulated high scatter conditions as in abdominal imaging. The absorption efficiency of each screen was measured and calculated. RESULTS: The measured s/p ratio varied within each set of screens. The s/P ratio was related to the absorption efficiency of primary radiation for the screen-film and CR system. No difference in the s/p ratio was seen between screen-film and CR systems when normalised for the primary absorption efficiency. CONCLUSIONS: Absorption efficiency of the imaging system is a major indicator of s/p ratio, for both screen-film and CR systems.

McLean D; Gray JE

1996-02-01

217

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.  

UK PubMed Central (United Kingdom)

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.

Tanaka N; Yano Y; Yabuuchi H; Akasaka T; Sasaki M; Ohki M; Morishita J

2013-01-01

218

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

Energy Technology Data Exchange (ETDEWEB)

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

Hong, Sung Hwan; Kim, Jong Hyo; Goo, Jin Mo and others [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

1999-09-01

219

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

International Nuclear Information System (INIS)

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

1999-01-01

220

Coupling High-Energy Radiography And Photon Activation Analysis (PAA) To Optimize The Characterization Of Nuclear Waste Packages  

International Nuclear Information System (INIS)

[en] Radiological characterization of nuclear waste packages is an industrial issue in order to select the best mode of storage. The alpha-activity, mainly due to the presence of actinides (235U, 238U, 239Pu,...) inside the package, is one of the most important parameter to assess during the characterization. Photon Activation Analysis (PAA) is a non-destructive active method (NDA method) based on the photofission process and on the detection of delayed particles (neutrons and gammas). This technique is well-adapted to the characterization of large concrete waste packages. However, PAA methods often require a simulation step which is necessary to analyze experimental results and to quantify the global mass of actinides. The weak point of this approach is that characteristics of the package are often not well-known, these latter having a huge impact on the final simulation result. High-energy radiography, based on the use of a linear electron accelerator (LINAC), allows to visualize the content of the package and is also a performing way to tune simulation models and to optimize the characterization process by PAA. In this article, we present high-energy radiography results obtained for two different large concrete waste packages in the SAPHIR facility (Active Photon and Irradiation System). This facility is dedicated to PAA study and development and setup for a decade in CEA Saclay. We also discuss possibilities offered by the coupling between high-energy radiography and PAA techniques.

2009-12-02

 
 
 
 
221

Computed tomography in analysis of total hip endoprosthesis  

International Nuclear Information System (INIS)

[en] 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

222

Industrial radiography  

International Nuclear Information System (INIS)

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

1992-01-01

223

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

224

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.).

1996-01-01

225

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)

[en] 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)

2007-01-01

226

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

Energy Technology Data Exchange (ETDEWEB)

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

Day, R. A.; Sankar, A. P.; Nailon, W. H.; MacLeod, A. S. [Department of Oncology Physics, Edinburgh Cancer Centre, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU (United Kingdom)

2011-02-15

227

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

228

Ambulating radiography  

International Nuclear Information System (INIS)

Strong gamme or X-ray sources are utilized for non-destructive testing of i.e. bridges. The activities involve certain risks of accident that might lead to serious injuries caused by radiation. The National Institute of Radiation Protection has during the laste decade greatly yhe inspection rate in this area. It has today made controls of most enterprieses running ambulating radiography. (O.S.).

1989-01-01

229

A voltage dependency analysis of the fixed kVp approach in variable part thickness radiography  

International Nuclear Information System (INIS)

[en] The dependency upon tube voltage of any accurate 'fixed kVp' approach to variable part thickness radiography is investigated by employing a theoretical model involving variation of the effective linear attenuation coefficient with tube voltage, for both ideal narrow and broad beam attenuation. Predicted increase rate ranges for tube charge (mAs) per unit thickness (centimetre) increment are presented as a function of tube voltage (kV) for several filtration cases. The increase rates range from 80 per cent per centimetre to approximately zero across the considered ranges of filtration, tube voltage, and beam area. The increase rates are seen to be heavily dependent upon the beam area/attenuation conditions at the image receptor and generally disagree significantly from the commonly used 25 per cent value of the standard approach. Copyright (2002) Australian Institute of Radiography

2002-01-01

230

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

International Nuclear Information System (INIS)

[en] 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)

2001-01-01

231

Post-irradiation analysis of SINQ target rods by thermal neutron radiography  

International Nuclear Information System (INIS)

Cylindrical lead rods from the SINQ spallation neutron source target have been investigated by thermal neutron-radiography/-tomography using a setup for highly activated samples and dysprosium loaded imaging plates. 2D radiography and 3D tomography results have been obtained from lead target rods from SINQ Target-5 irradiated for 2 years, corresponding a total proton charge accumulation of 10.85 Ah. This was the only non-destructive evaluation method capable to visualize macroscopic material changes induced by proton and/or neutron irradiation. The size and location of defects were identified and areas of interest could be selected for further destructive testing. The high sensitivity of neutrons for hydrogen makes this technique particularly useful when looking for metal hydrides. The formation of lens-shaped zirconium hydride blisters has been identified at the steel/Zircaloy interface of a lead rod with a combined steel/zircaloy cladding. Qualitative and quantitative information has been derived from this neutron radiography inspection

2006-09-15

232

Post-irradiation analysis of SINQ target rods by thermal neutron radiography  

Energy Technology Data Exchange (ETDEWEB)

Cylindrical lead rods from the SINQ spallation neutron source target have been investigated by thermal neutron-radiography/-tomography using a setup for highly activated samples and dysprosium loaded imaging plates. 2D radiography and 3D tomography results have been obtained from lead target rods from SINQ Target-5 irradiated for 2 years, corresponding a total proton charge accumulation of 10.85 Ah. This was the only non-destructive evaluation method capable to visualize macroscopic material changes induced by proton and/or neutron irradiation. The size and location of defects were identified and areas of interest could be selected for further destructive testing. The high sensitivity of neutrons for hydrogen makes this technique particularly useful when looking for metal hydrides. The formation of lens-shaped zirconium hydride blisters has been identified at the steel/Zircaloy interface of a lead rod with a combined steel/zircaloy cladding. Qualitative and quantitative information has been derived from this neutron radiography inspection.

Vontobel, Peter [Spallation Neutron Source Division, Paul Scherrer Institut, CH-5232 Villigen-PSI (Switzerland)]. E-mail: peter.vontobel@psi.ch; Tamaki, Masayoshi [Nagoya University, Department for Nuclear Engineering, Chikusa Ku, Nagoya, Aichi 4648603 (Japan); Mori, Noriaki [Nagoya University, Department for Nuclear Engineering, Chikusa Ku, Nagoya, Aichi 4648603 (Japan); Ashida, Takaki [Nagoya University, Department for Nuclear Engineering, Chikusa Ku, Nagoya, Aichi 4648603 (Japan); Zanini, Luca [Spallation Neutron Source Division, Paul Scherrer Institut, CH-5232 Villigen-PSI (Switzerland); Lehmann, Eberhard H. [Spallation Neutron Source Division, Paul Scherrer Institut, CH-5232 Villigen-PSI (Switzerland); Jaggi, Matthias [Spallation Neutron Source Division, Paul Scherrer Institut, CH-5232 Villigen-PSI (Switzerland)

2006-09-15

233

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

Energy Technology Data Exchange (ETDEWEB)

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)

Handa, Madoka; Watanabe, Yosihiko [Tokyo Metropolitan Isotope Research Center (Japan)

1996-03-01

234

On-Board Patient Positioning for Head-and-Neck IMRT: Comparing Digital Tomosynthesis to Kilovoltage Radiography and Cone-Beam Computed Tomography  

International Nuclear Information System (INIS)

Purpose: High-precision intensity-modulated radiotherapy demands high patient positioning accuracy. On-board digital tomosynthesis (DTS) provides three-dimensional (3D) image guidance for daily positioning with a lower imaging dose, faster acquisition, and more geometric flexibility than 3D cone-beam computed tomography (CBCT). This clinical study evaluated DTS as a daily imaging technique for patient positioning and compared the results with 3D CBCT and two-dimensional (2D) radiography. Methods and Materials: Head and neck cancer patients undergoing intensity-modulated radiotherapy were studied. For each session, the patient was positioned using laser marks. On-board imaging data sets, including 2D kilovoltage radiographs, DTS, and CBCT, were obtained to measure the daily patient positioning variations. The mean and standard deviations of the positioning variations in the translational and rotational directions were calculated. The positioning differences among 2D radiography, DTS, and CBCT were analyzed. Results: Image data sets were collected from 65 treatment fractions for 10 patients. The systematic patient positioning variation was o-1.99o in the rotational direction. The mean vector isocenter variation was 0.48 cm. DTS with 40 deg. and 20 deg. scan angles in the coronal or sagittal directions yielded the same results for patient positioning. DTS performance was comparable to that of CBCT, with positioning differences of o. The positioning difference between 2D radiography and DTS was ?0.1 cm and 0.2 cm in the vertical/longitudinal and lateral directions. Conclusion: Our results have demonstrated that DTS is a comparable 3D imaging technique to CBCT for daily patient positioning of head-and-neck patients as determined by manual registration of bony anatomy.

2007-10-01

235

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

UK PubMed Central (United Kingdom)

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

Rosário PW; Tavares WC; Barroso AL; Rezende LL; Padrão EL; Purisch S

2008-02-01

236

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

International Nuclear Information System (INIS)

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

2008-01-01

237

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

238

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.

1995-01-01

239

Digital radiography  

International Nuclear Information System (INIS)

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

1992-01-01

240

RADIOGRAPHY SYSTEM  

UK PubMed Central (United Kingdom)

A radiography system comprising: an X-ray sensor (12) that converts X-ray to an image signal a drive control unit (13) that communicates with an external device (1) via wireless radio waves to drive and control the sensor a power source unit (15) that supplies an electric power to the X-ray sensor (12) and the drive control unit (13) and a display means (16) that shifts the display mode in accordance with either one of the sending/reception state of the wireless radio communication and the residual amount in the power source unit (15) and the drive state of the sensor.

KOBAYASHI KENSUKE

 
 
 
 
241

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  

International Nuclear Information System (INIS)

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 UO2 pellet and two-natural UO2 pellet that are loaded into a Zircaloy tube. There are somewhat difference in the size and shape among those UO2 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 UO2 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)

2002-01-01

242

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

243

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

244

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-07-01

245

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

International Nuclear Information System (INIS)

[en] 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

2005-01-01

246

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 of cross sectional images of various mandibular mass lesions. Of these, imaging features of ameloblastoma and central giant cell granuloma (CGCG) were studied and compared, which is reported in this paper.

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

2001-01-01

247

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

248

Accuracy of digital panoramic radiography in the diagnosis of temporal bone pneumatization: A study in vivo using cone-beam-computed tomography.  

UK PubMed Central (United Kingdom)

PURPOSE: The objective of the study was to determine the diagnostic accuracy of panoramic radiographs in the evaluation of pneumatization of the temporal bone, with confirmation of the diagnosis by cone-beam-computed tomography (CBCT) images. METHODS: Images of 200 patients' digital panoramic radiographies and CBCT were examined by three evaluators regarding the presence or absence of pneumatization on temporomandibular joint (TMJ) fossa and/or articular eminence. When present, the defect was classified as uni- or multilocular, and as unilateral or bilateral. Areas under the ROC curve were compared to assess the accuracy of panoramic radiograph. RESULTS: The values obtained in the comparisons ranged from Az = 0.67 to 0.55 (Az = area under the ROC curve). CONCLUSIONS: The panoramic radiograph, is not the exam of choice for detecting the presence of these air cells based on its medium to low accuracy for diagnosis of pneumatized articular eminence and TMJ fossa when compared to CBCT.

de Rezende Barbosa GL; Nascimento MD; Ladeira DB; Bomtorim VV; da Cruz AD; Almeida SM

2013-07-01

249

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

250

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

2013-01-01

251

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)

2011-01-01

252

Portable digital electronic radiography system  

International Nuclear Information System (INIS)

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

1995-01-01

253

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

2001-01-01

254

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

Science.gov (United States)

The purpose of this study was to develop of kinetic analysis method for PACS management and computer-aided diagnosis. We obtained dynamic chest radiographs (512x512, 8bit, 4fps, and 1344x1344, 12bit, 3fps) of five healthy volunteers during respiration using an I.I. system twice, and one healthy volunteer using dynamic FPD system. Optical flows of images were obtained using customized block matching technique, and were divided into a direction, and transformed into the RGB color. Density was determined by the sum pixel length of movement during respiration phase. The made new static image was defined as the "kinetic map". The evaluation of patient's collation was performed with a template matching to the three colors. The same person's each correlation value and similar-coefficient which is defined in this study were statistically significant high (P<0.01). We used the artificial neural network (ANN) for the judgment of the same person. Five volunteers were divided into two groups, three volunteers and two volunteers became a training signal and unknown signal. Correlation value and similar-coefficient was used for the input signal, and ANN was designed so that the same person's probability might be outputted. The average of the specificity of the unknown signal obtained 98.2%. The kinetic map including the imitation tumor was used for the simulation. The tumor was detected by temporal subtraction of kinetic map, and then the superior sensitivity was obtained. Our analysis method was useful in risk management and computer-aided diagnosis.

Tsuchiya, Yuichiro; Kodera, Yoshie

2005-04-01

255

Affective Computing and Sentiment Analysis  

CERN Multimedia

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

256

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

1990-01-01

257

Application of neutron radiography in civil engineering  

International Nuclear Information System (INIS)

The application is described of neutron transmission analysis and radiography in analyzing the distribution and kinetics of water in porous building materials. The kinetics and distribution are studied of liquid hydrophobic or hydroinsulating preservation agents in penetrating building material, and a standard technique is presented. Examples are described in detail of neutron radiography applications in civil engineering. (E.J.). 8 refs.

1989-01-01

258

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

259

Performance analysis of parallel computations  

Energy Technology Data Exchange (ETDEWEB)

This study investigates the modeling and analysis of performance of parallel computations. Time cost is used in the study as the performance metrics. It is assumed parallel computations under investigation reside in a computer system in which there is a limited number of processors, all the processors have the same speed, and they communicate with each other through a shared memory. It was found that the performance of parallel computations depends on the input, the algorithm, the data structure, the processor speed, the number of processors, the processing power allocation, the communication, the execution overhead, and the execution environment. The performance is defined as a function of the first seven factors listed above. The computation structure model is modified to describe the impact of the number of processors, the processing power allocation, and the communication on performance. Activation signals used in the computation structure model are allowed to carry processors and processing power allocation policy. Once a node in a parallel computation receives all the required signals, it uses the processors and allocation policy carried by the signals to perform the specified operations.

Qin, B.

1988-01-01

260

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

UK PubMed Central (United Kingdom)

OBJECTIVE: To assess the impact of digital tomosynthesis (DTS) on the radiological investigation of patients with suspected pulmonary lesions on chest radiography (CXR). METHODS: 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. RESULTS: 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?

Quaia E; Baratella E; Cernic S; Lorusso A; Casagrande F; Cioffi V; Cova MA

2012-09-01

 
 
 
 
261

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

262

Object position and image magnification in dental panoramic radiography: a theoretical analysis.  

UK PubMed Central (United Kingdom)

OBJECTIVES: The purpose of our study was to investigate how image magnification and distortion in dental panoramic radiography are influenced by object size and position for a small round object such as a ball bearing used for calibration. METHODS: Two ball bearings (2.5 mm and 6 mm in diameter) were placed at approximately the same position between the teeth of a plastic skull and radiographed 21 times. The skull was replaced each time. Their images were measured by software using edge detection and ellipse-fitting algorithms. Using a standard definition of magnification, equations were derived to enable an object's magnification to be determined from its position and vice versa knowing the diameter and machine parameters. RESULTS: The average magnification of the 2.5 mm ball bearing was 1.292 (0.0445) horizontally and 1.257 (0.0067) vertically with a mean ratio of 1.028 (0.0322); standard deviations are in parentheses. The figures for the 6 mm ball bearing were 1.286 (0.0068), 1.255 (0.0018) and 1.025 (0.0061), respectively. Derived positions of each ball bearing from magnification were more consistent horizontally than vertically. There was less variation in either direction for the 6 mm ball bearing than the 2.5 mm one. CONCLUSIONS: Automatic measurement of image size resulted in less variation in vertical magnification values than horizontal. There are only certain positions in the focal trough that achieve zero distortion. Object location can be determined from its diameter, measured magnification and machine parameters. The 6 mm diameter ball bearing is preferable to the 2.5 mm one for more reliable magnification measurement and position determination.

Devlin H; Yuan J

2013-01-01

263

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

International Nuclear Information System (INIS)

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

2007-01-01

264

National Survey of Radiation Doses of Pediatric Chest Radiography in Korea: Analysis of the Factors Affecting Radiation Doses  

International Nuclear Information System (INIS)

To investigate radiation doses in pediatric chest radiography in a national survey and to analyze the factors that affect radiation doses. The study was based on the results of 149 chest radiography machines in 135 hospitals nationwide. For each machine, a chest radiograph was obtained by using a phantom representing a 5-year-old child (ATOM dosimetry phantom, model 705-D, CIRS, Norfolk, VA, USA) with each hospital's own protocol. Five glass dosimeters (M-GD352M, Asahi Techno Glass Corporation, Shizuoka, Japan) were horizontally installed at the center of the phantom to measure the dose. Other factors including machine's radiography system, presence of dedicated pediatric radiography machine, presence of an attending pediatric radiologist, and the use of automatic exposure control (AEC) were also evaluated. The average protocol for pediatric chest radiography examination in Korea was 94.9 peak kilovoltage and 4.30 milliampere second. The mean entrance surface dose (ESD) during a single examination was 140.4 microgray (?Gy). The third quartile, median, minimum and maximum value of ESD were 160.8 ?Gy, 93.4 ?Gy, 18.8 ?Gy, and 2334.6 ?Gy, respectively. There was no significant dose difference between digital and non-digital radiography systems. The use of AEC significantly reduced radiation doses of pediatric chest radiographs (p

2012-01-01

265

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 r 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

266

Accuracy of plain film radiography in the diagnosis of opacities of the pneumatic system of the skull - comparison with computed tomography  

International Nuclear Information System (INIS)

[en] The accuracy of plain film radiography in the diagnosis of opacities of the pneumatic system of the skull was evaluated in 302 patients in comparison with computed tomography. Plain films were performed using standard projections (Schueller, Stenvers, NNH o.n., paranaseal sinus). Specificity was high (90% and over) with the exception of the maxillary sinus (82%). More sensitive, non-invasive diagnostic imaging techniques are indicated in the following conditions: therapy-refractory opacification of one sinus, indeterminate otological symptoms in the presence of a low pneumatised mastoid, and definitive exclusion of infectious foci in the pneumatic system of the skull. (orig./GDG)[de] Die Wertigkeit der konventionellen Nativdiagnostik im Nachweis von Verschattungen der pneumatisierten Raeume des Schaedels wurde computertomographisch bei 302 Patienten ueberprueft. Die konventionelle Nativdiagnostik erfolgt in den Standardprojektionen (Schueller, Stenvers, NNH o.n., NNH o.m). Mit Ausnahme der Oberkieferhoehlen (82%) lag die Spezifitaet in den uebrigen pneumatisierten Raeumen bei ueber 90%. Indikationen fuer den gezielten Einsatz von sensitiveren, nicht-invasiven diagnostischen Verfahren ergeben sich aus den vorliegenden Resultaten bei therapierefraktaerer NNH-Verschattung in nur einer Hoehle, unklarer klinischer, otologischer Symptomatik bei geringer mastoidaler Pneumatisation und bei hochrangiger Bedeutung eines Fokusausschlusses. (orig./GDG)

1991-01-01

267

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

UK PubMed Central (United Kingdom)

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 CF; Caroprese B; Desai P

2012-01-01

268

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; Caroprese Blas; Desai Pushkar

2012-01-01

269

Computer aided safety analysis 1989  

International Nuclear Information System (INIS)

[en] 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

1990-01-01

270

Evaluation of mean glandular dose and modulation transfer function for different tube potentials and target-filter combinations in computed radiography mammography.  

UK PubMed Central (United Kingdom)

BACKGROUND: Different target-filter combinations in computed radiography have different impacts on the dose and image quality in digital radiography. This study aims to evaluate the mean glandular dose (MGD) and modulation transfer function (MTF) of various target-filter combinations by investigating the signal intensities of X-ray beams. METHODS: General Electric (GE) Senographe DMR Plus mammography unit was used for MGD and MTF evaluation. The measured MGD was compared with the dose reference level (DRL), whereas the MTF was evaluated using ImageJ 1.46o software. A modified Mammography Accreditation Phantom RMI 156 was exposed using different target-filter combinations of molybdenum-molybdenum (Mo-Mo), molybdenum-rhodium (Mo-Rh) and rhodium-rhodium (Rh-Rh) at two different tube voltages, 26 kV and 32 kV with 50 mAs. RESULTS: In the MGD evaluations, all target-filters gave an MGD value of < 1.5 mGy. The one-way ANOVA test showed a highly significant interaction between the MGD and the kilovoltage and target-filter material used (26 kV: F (2,12) = 49,234, P = 0.001;32 kV: F (2,12) = 89,972, P = 0.001). A Tukey post-hoc test revealed that the MGD for 26 kV and 32 kV was highly affected by the target-filter combinations. The test of homogeneity of variances indicates that the MGD varies significantly for 26 kV and 32 kV images (0.045 and 0.030 (P < 0.05), respectively). However, the one-way ANOVA for the MTF shows that no significant difference exists between the target-filter combinations used with 26 kV and 32 kV images either in parallel or perpendicular to the chest wall side F (2,189) = 0.26, P > 0.05). CONCLUSION: Higher tube voltage and atomic number target-filter yield higher MGD values. However, the MTF is independent of the X-ray energy and the type of target-filter combinations used.

Abdul Aziz SA; Mohd Saparudin AK; Harun AZ

2013-05-01

271

Radiography with polarised neutrons  

International Nuclear Information System (INIS)

[en] 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

272

Flow characterization of glauconitic sandstones by integrated Dynamic Neutron Radiography and image analysis of backscattered electron micrographs  

Energy Technology Data Exchange (ETDEWEB)

The effects of porosity and pore geometry on the fluid saturation and immiscible displacement of greensand reservoir rocks were investigated on eight samples from the North Sea basin. Dynamic Neutron Radiography (DNR) was used to image the front stability during displacement experiments where oil was infiltrating water-saturated samples. The flow characteristics were related to petrography and pore geometry, which may be determined by image analysis of backscattered electron (BSE) micrographs. The fluid saturation observed in each DNR image was modelled in a corresponding BSE image as a means of evaluating the effect of pore geometry on front stability. Piston-like displacement and channelling were observed and these flow patterns were found to reflect variations in pore geometry. The samples with piston-like displacement have homogeneous pore space, whereas the samples with channelling have heterogeneous pore space, with spatial variations in porosity and pore size. The modelled saturation distribution was interpreted using results from petrographic and petrophysical analyses. The results suggest that the micropores of the glauconite grains and clay minerals contain water, whereas the oil is moving through the intergranular pore space during the displacement experiment. (Author)

Solymar, M. [Chalmers Univ. of Technology, Dept. of Geology, Gothenburg (Sweden); Fabricius, I. [Technical Univ. of Denmark, Dept. of Environment and Resources, Lyngby (Denmark); Middleton, M. [Curtin Univ. of Technology, School of Applied Geology, Perth, WA (Australia)

2003-01-01

273

Compton radiography, 3  

International Nuclear Information System (INIS)

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

1977-01-01

274

Computational analysis of cerebral cortex  

International Nuclear Information System (INIS)

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

2010-01-01

275

Digital radiography versus conventional radiography during excretory urography: our experience  

International Nuclear Information System (INIS)

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

1990-01-01

276

Digital radiography versus conventional radiography during excretory urography: our experience  

Energy Technology Data Exchange (ETDEWEB)

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

Cervi, P.M.; Bighi, S.; Merlo, L.; Lupi, L.; Vita, G. (S. Anna Hospital, FERRARA (IT))

1990-01-01

277

Proton nuclear scattering radiography  

International Nuclear Information System (INIS)

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

1982-04-03

278

Specific radiography technique  

International Nuclear Information System (INIS)

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

2008-01-01

279

Bone X-Ray (Radiography)  

Science.gov (United States)

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

280

Multiple-image radiography  

International Nuclear Information System (INIS)

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

2003-12-07

 
 
 
 
281

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

Energy Technology Data Exchange (ETDEWEB)

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.)

Chen, Tian-wu [West China Hospital of Sichuan University, Department of Radiology, Chengdu, Sichuan (China); Nanchong Central Hospital and Second Medical School 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); Wang, Qi-ling; Dong, Zhi-hui; Yu, Jian-qun; Zhuang, Zhang-pu; Hou, Chang-ling; Li, Zhen-lin [West China Hospital of Sichuan University, Department of Radiology, Chengdu, Sichuan (China)

2009-11-15

282

Image Quality, lesion detection, and diagnostic efficacy in digital mammography: Full-field digital mammography versus computed radiography-based mammography using digital storage phosphor plates  

Energy Technology Data Exchange (ETDEWEB)

Objective: To compare image quality, the lesion detection, and the diagnostic efficacy of full-field digital mammography (FFDM) and computed radiography-based mammography using digital storage phosphor plates (DSPM) in the evaluation of breast lesions. Materials and methods: In this prospective study, 150 patients with suspicious breast lesions underwent FFDM and DSPM. Nine aspects of image quality (brightness, contrast, sharpness, noise, artifacts, and the detection of anatomic structures, i.e., skin, retromamillary space, glandular tissue, and calcifications) were evaluated by five radiologists. In addition, the detection of breast lesions and the diagnostic efficacy, based on the BI-RADS classification, were evaluated with histologic and follow-up correlation. Results: For contrast, sharpness, and the detection of all anatomic structures, FFDM was rated significantly better (p < 0.05). Mass lesions were equally detected, whereas FFDM detected more lesions consisting of calcifications (85 versus 75). DSPM yielded two false-negative results. Both lesions were rated BI-RADS 4 with FFDM, but BI-RADS 2 with DSPM. Both were invasive carcinoma at histology. The sensitivity, specificity, PPV, NPV, and accuracy of FFDM were 1.0, 0.397, 0.636, 1.0, and 0.707, compared to 0.974, 0.397, 0.630, 0.935, and 0.693 of DSPM. Conclusion: Based on image quality parameters, FFDM is, in part, significantly better than DSPM. Furthermore, the detection of breast lesions with calcifications is favorable with FFDM. However, the diagnostic efficacy of FFDM and DSPM was equal. The interpretation of the false-negative results suggests that the perception and characterization of breast lesions is not defined solely by the digital mammography system but is strongly influenced by the radiologist, who is one of the determinants in the interpretation of breast imaging.

Schueller, Gerd [Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria)], E-mail: gerd.schueller@meduniwien.ac.at; Riedl, Christopher C.; Mallek, Reinhold; Eibenberger, Klemens; Langenberger, Herbert; Kaindl, Elisabeth; Kulinna-Cosentini, Christiane [Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Rudas, Margaretha [Department of Pathology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Helbich, Thomas H. [Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria)

2008-09-15

283

Simulation of the radiography formation process from CT patient volume  

International Nuclear Information System (INIS)

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

1998-01-01

284

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

UK PubMed Central (United Kingdom)

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

Balasundaram A; Shah P; Hoen MM; Wheater MA; Bringas JS; Gartner A; Geist JR

2012-01-01

285

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

Science.gov (United States)

Objectives. To compare the ability of endodontists to determine the size of apical pathological lesions and select the most appropriate choice of treatment based on lesions' projected image characteristics using 2 D and 3 D images. Study Design. Twenty-four subjects were selected. Radiographic examination of symptomatic study teeth with an intraoral periapical radiograph revealed periapical lesions equal to or greater than 3 mm in the greatest diameter. Cone-beam Computed tomography (CBCT) images were made of the involved teeth after the intraoral periapical radiograph confirmed the size of lesion to be equal to greater than 3 mm. Six observers (endodontists) viewed both the periapical and CBCT images. Upon viewing each of the images from the two imaging modalities, observers (1) measured lesion size and (2) made decisions on treatment based on each radiograph. Chi-square test was used to look for differences in the choice of treatment among observers. Results. No significant difference was noted in the treatment plan selected by observers using the two modalities (?(2)(3) = .036, P > 0.05). Conclusion. Lesion size and choice of treatment of periapical lesions based on CBCT radiographs do not change significantly from those made on the basis of 2 D radiographs. PMID:23056050

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

2012-09-30

286

Radiologic anatomy of the inferior lung margins as demonstrated on computed radiography with enhancement of low frequencies.  

Science.gov (United States)

The aim of this work was to describe the radiologic anatomy of the inferior lung margins (ILMs). The method was to enhance the low frequencies of 50 normal chest computed radiographs. On each side, the anterior and posterior ILMs were divided into two halves. The frequency of visibility of each half of each ILM was calculated as their shape, lateral and medial continuities, depth, and vertebral level. The differences were compared by a paired Student t-test. The right posterior ILM was always visible and usually concave upward (94%). Its height was 8.7 +/- 1.6 cm. Its most inferior part faced L1 or L2 in 92% of cases. It was continuous medially inside with the azygo-esophageal recess in 96% of cases. The left posterior ILM was not visible laterally in 34% of cases and medially in 60% of cases. It was most often concave upward (82% of cases). Its height was 6.9 +/- 1.5 cm. Its most inferior part was at the level of L1 or L2. It was continuous medially with either the left paraspinal line or the paraaortic line. The right anterior ILM was visible in 76% of cases. It was most often oblique upward and medially (46%) or concave upward (33%) and often notched (38%). The left anterior ILM was visible in 64% of cases and more often oblique inward and upward (58%). It was continuous medially with the left inferior precardiac recess. The anterior ILMs were more variable than the posterior. The posterior ILMs were very similar in shape and inferior level and differed in depth only by the difference of height of the diaphragmatic cupolas. PMID:9381333

Frija, J; de Kerviler, E; Zagdanski, A M

1997-01-01

287

Radiologic anatomy of the inferior lung margins as demonstrated on computed radiography with enhancement of low frequencies.  

UK PubMed Central (United Kingdom)

The aim of this work was to describe the radiologic anatomy of the inferior lung margins (ILMs). The method was to enhance the low frequencies of 50 normal chest computed radiographs. On each side, the anterior and posterior ILMs were divided into two halves. The frequency of visibility of each half of each ILM was calculated as their shape, lateral and medial continuities, depth, and vertebral level. The differences were compared by a paired Student t-test. The right posterior ILM was always visible and usually concave upward (94%). Its height was 8.7 +/- 1.6 cm. Its most inferior part faced L1 or L2 in 92% of cases. It was continuous medially inside with the azygo-esophageal recess in 96% of cases. The left posterior ILM was not visible laterally in 34% of cases and medially in 60% of cases. It was most often concave upward (82% of cases). Its height was 6.9 +/- 1.5 cm. Its most inferior part was at the level of L1 or L2. It was continuous medially with either the left paraspinal line or the paraaortic line. The right anterior ILM was visible in 76% of cases. It was most often oblique upward and medially (46%) or concave upward (33%) and often notched (38%). The left anterior ILM was visible in 64% of cases and more often oblique inward and upward (58%). It was continuous medially with the left inferior precardiac recess. The anterior ILMs were more variable than the posterior. The posterior ILMs were very similar in shape and inferior level and differed in depth only by the difference of height of the diaphragmatic cupolas.

Frija J; de Kerviler E; Zagdanski AM

1997-01-01

288

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

International Nuclear Information System (INIS)

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

2008-01-01

289

Clinical feline dental radiography.  

UK PubMed Central (United Kingdom)

Dental radiography is a necessary diagnostic modality in small animal practice. It is not possible to accurately assess and diagnose tooth resorption, periodontal disease, endodontic disease, neoplasia and injury without it. Dental radiography is also necessary for treatment and assessment of the patient postoperatively.

Lemmons M

2013-05-01

290

METHOD AND SYSTEM FOR INTELLIGENT QUALITATIVE AND QUANTITATIVE ANALYSIS OF DIGITAL RADIOGRAPHY SOFTCOPY READING  

UK PubMed Central (United Kingdom)

The present invention describes a method and system for intelligent diagnost ic relevant information processing and analysis. Information associated with a patient is processed via an image reading platform. Based on such processed information, a matrix of diagnosis decisions containing diagnostic related information is generated via a matrix of diagnosis decision platform. A diagnostic decision is made based on the diagnostic relevant information. Th e image reading platform and/or the matrix of diagnosis decision platform encapsulate information and toolkits to be used to manipulate the informatio n.

WEI GUO-QING; LIANG CHENG-CHUNG; QUIAN JIANZHONG; FAN LI

291

Proximal caries detection accuracy using intraoral bitewing radiography, extraoral bitewing radiography and panoramic radiography.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To compare proximal caries detection using intraoral bitewing, extraoral bitewing and panoramic radiography. METHODS: 80 extracted human premolar and molar teeth with and without proximal caries were used. Intraoral radiographs were taken with Kodak Insight film (Eastman Kodak Co., Rochester, NY) using the bitewing technique. Extraoral bitewing and panoramic images were obtained using a Planmeca Promax Digital Panoramic X-ray unit (Planmeca Inc., Helsinki, Finland). Images were evaluated by three observers twice. In total, 160 proximal surfaces were assessed. Intra- and interobserver kappa coefficients were calculated. Scores obtained from the three techniques were compared with the histological gold standard using receiver operating characteristic analysis. Az values for each image type, observer and reading were compared using z-tests, with a significance level of ? = 0.05. RESULTS: Kappa coefficients ranged from 0.883 to 0.963 for the intraoral bitewing, from 0.715 to 0.893 for the extraoral bitewing, and from 0.659 to 0.884 for the panoramic radiography. Interobserver agreements for the first and second readings for the intraoral bitewing images were between 0.717 and 0.780, the extraoral bitewing readings were between 0.569 and 0.707, and the panoramic images were between 0.477 and 0.740. The Az values for both readings of all three observers were highest for the intraoral bitewing. Az values for the extraoral bitewing images were higher than those of the panoramic images without statistical significance (p > 0.05). CONCLUSION: Intraoral bitewing radiography was superior to extraoral bitewing and panoramic radiography in diagnosing proximal caries of premolar and molar teeth ex vivo. Similar intra- and interobserver coefficients were calculated for extraoral bitewing and panoramic radiography.

Kamburoglu K; Kolsuz E; Murat S; Yüksel S; Ozen T

2012-09-01

292

[X-ray radiography as a method of detailing the analysis of sedimentary facies, based on example of the Cergowa sandstones (Flysch Carpathians)].  

UK PubMed Central (United Kingdom)

The paper presents the X-ray radiography as a method useful for the visualization of sedimentary structures in macroscopically homogeneous rocks. The radiographic analysis presented here bases on the example the Cergowa turbidite sandstones. The applied technique reveals that some of the apparently homogeneus Cergowa sandstones possess internal sedimentary structure of cross-lamination, which reflects on the sedimentological interpretation of the depositional mechanisms of this rock unit. This is the first application of this method in research on the Carpathian Flysch sedimentation.

Pszonka J; Wendorff M; Jucha K; Bartynowska K; Urbanik A

2013-01-01

293

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

International Nuclear Information System (INIS)

[en] 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

2006-01-01

294

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-02-15

295

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; N. Sathees Kumar; N. Karthick?

2013-01-01

296

International neutron radiography newsletter  

International Nuclear Information System (INIS)

At the First World Conference on Neutron Radiography it was decided to continue the 'Neutron Radiography Newsletter', published previously by J.P. Barton, as the 'International Neutron Radiography Newsletter' (INRNL), with J.C. Domanus as editor. The British Journal of Non-Desctructive Testing (BJNDT) has agreed to publish the INRNL in its column 'NDT Bookcase'. The Revue Practique de Control Industriel has also agreed to publish the French version of the INRNL. Up till now 12 issues of the INRNL were published in the BJNDT. They are reviewed below. (author).

1986-01-01

297

Grid computing in image analysis.  

UK PubMed Central (United Kingdom)

Diagnostic surgical pathology or tissue–based diagnosis still remains the most reliable and specific diagnostic medical procedure. The development of whole slide scanners permits the creation of virtual slides and to work on so-called virtual microscopes. In addition to interactive work on virtual slides approaches have been reported that introduce automated virtual microscopy, which is composed of several tools focusing on quite different tasks. These include evaluation of image quality and image standardization, analysis of potential useful thresholds for object detection and identification (segmentation), dynamic segmentation procedures, adjustable magnification to optimize feature extraction, and texture analysis including image transformation and evaluation of elementary primitives. Grid technology seems to possess all features to efficiently target and control the specific tasks of image information and detection in order to obtain a detailed and accurate diagnosis. Grid technology is based upon so-called nodes that are linked together and share certain communication rules in using open standards. Their number and functionality can vary according to the needs of a specific user at a given point in time. When implementing automated virtual microscopy with Grid technology, all of the five different Grid functions have to be taken into account, namely 1) computation services, 2) data services, 3) application services, 4) information services, and 5) knowledge services. Although all mandatory tools of automated virtual microscopy can be implemented in a closed or standardized open system, Grid technology offers a new dimension to acquire, detect, classify, and distribute medical image information, and to assure quality in tissue–based diagnosis.

Kayser K; Görtler J; Borkenfeld S; Kayser G

2011-01-01

298

Grid computing in image analysis.  

Science.gov (United States)

Diagnostic surgical pathology or tissue–based diagnosis still remains the most reliable and specific diagnostic medical procedure. The development of whole slide scanners permits the creation of virtual slides and to work on so-called virtual microscopes. In addition to interactive work on virtual slides approaches have been reported that introduce automated virtual microscopy, which is composed of several tools focusing on quite different tasks. These include evaluation of image quality and image standardization, analysis of potential useful thresholds for object detection and identification (segmentation), dynamic segmentation procedures, adjustable magnification to optimize feature extraction, and texture analysis including image transformation and evaluation of elementary primitives. Grid technology seems to possess all features to efficiently target and control the specific tasks of image information and detection in order to obtain a detailed and accurate diagnosis. Grid technology is based upon so-called nodes that are linked together and share certain communication rules in using open standards. Their number and functionality can vary according to the needs of a specific user at a given point in time. When implementing automated virtual microscopy with Grid technology, all of the five different Grid functions have to be taken into account, namely 1) computation services, 2) data services, 3) application services, 4) information services, and 5) knowledge services. Although all mandatory tools of automated virtual microscopy can be implemented in a closed or standardized open system, Grid technology offers a new dimension to acquire, detect, classify, and distribute medical image information, and to assure quality in tissue–based diagnosis. PMID:21516880

Kayser, Klaus; Görtler, Jürgen; Borkenfeld, Stephan; Kayser, Gian

2011-01-01

299

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

300

High energy neutron radiography  

International Nuclear Information System (INIS)

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.

1996-01-01

 
 
 
 
301

Applied Time Series Analysis and Innovative Computing  

CERN Multimedia

Contains the applied time series analysis and innovative computing paradigms, with frontier application studies for the time series problems. This monograph provides a systematic introduction to the use of innovative computing paradigms as an investigative tool for applications in time series analysis

Ao, Sio-Iong

2010-01-01

302

High quality neutron radiography  

International Nuclear Information System (INIS)

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

1995-01-01

303

Core description and analysis using X-radiography and cat-scanning: examples from Sacramento and San Joaquin basins, California  

Energy Technology Data Exchange (ETDEWEB)

X-radiographs of cores from Forbes deep basin sands, the tar-saturated paralic sands of the Temblor and the Tulare fluvial sands and silts, as well as fractured siliceous units (the Monterey Formation and equivalents) reveal geologic features that are either not visible or barely discernible to the naked eye. These features include changes in grain size, grading, ripple lamination to cross-bedding, cyclic couplets in tidal sequences, bioturbation and burrowing, and fracture patterns and filling. Forbes core x-radiography from the northern Sacramento basin clearly shows a sequence of thinly bedded sand and mudstones that are microripple cross-laminated. Partial Bouma sequences (Ta-b or Tb with Ta-c) are characteristic of the thickly bedded sands below the ripple-laminated units. Cyclic sequences of mud-turbidites and finely laminated, very fine-grained sands to coarse silts characterize a sand-poor sequence that overlies a massive to indistinctly thin-bedded sand. Most of these features described above are barely discernible without x-radiography, yet all provide major input to the interpretation of the depositional environment of the Forbes Formation, as well as information regarding reservoir continuity. Tar or heavy-oil saturation of cores can be a severe problem when cores are examined. In a Tulare Formation core sequence that was x-radiographed, essentially no bedding was visible, even using UV photography. However, extensive fluvial cross-bedding throughout the core was revealed by the x-radiography. A similar, heavy oil masking problem in a Temblor Formation core near East Coalinga was also resolved by the x-ray technique. The reservoir is divided into multiple, thin, tidal couplets (4-6 in.) of oil-saturated sand separated by 1 to 3 in. thick mudstones.

Fischer, P.J.; Setiawan, J.; Cherven, V.B.

1986-04-01

304

Computer assistance in food analysis.  

UK PubMed Central (United Kingdom)

Laboratory computer links are a key part of acquisition, movement, and interpretation of certain types of data. Remote information retrieval from databases such as the Chemical Information System provides the analyst with structural and toxicological information via a laboratory terminal. Remote processing of laboratory data by large computers permits the application of pattern recognition techniques to the solution of complex multivariate problems such as the detection of food adulteration.

Dusold LR; Roach JA

1986-09-01

305

Computer assistance in food analysis.  

Science.gov (United States)

Laboratory computer links are a key part of acquisition, movement, and interpretation of certain types of data. Remote information retrieval from databases such as the Chemical Information System provides the analyst with structural and toxicological information via a laboratory terminal. Remote processing of laboratory data by large computers permits the application of pattern recognition techniques to the solution of complex multivariate problems such as the detection of food adulteration. PMID:3771445

Dusold, L R; Roach, J A

306

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 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 ca (more) da 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 patients and with osteoporosis.The elements analyzed consist in five dry human mandibles. The four studied zones of each mandible were selected in the mandible body under the alve (more) olar 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

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

2006-09-01

307

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

Directory of Open Access Journals (Sweden)

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

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

2006-01-01

308

Computer Analysis of Doppler Signals  

Directory of Open Access Journals (Sweden)

Full Text Available 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.

DR?GHICIU Nicolae; POPA Sorin

2011-01-01

309

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

310

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.)

1986-01-01

311

Functioning of industrial radiography services  

International Nuclear Information System (INIS)

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

1988-01-01

312

Radiography of the Lower Extremity  

Science.gov (United States)

Lower Extremity Radiography What you need to know about… Lower extremity radiography is another way of saying x-ray ... procedure when you have an injury to a lower extremity or you experience unexplained pain in the area. ...

313

Quantum Computer Circuit Analysis and Design.  

Science.gov (United States)

Recent developments in the Riemannian geometry of quantum computation offer a new approach to the analysis of quantum computation. A geodesic equation defined on the SU(2n) group manifold, representing quantum gate operations on n qubits, may be used to d...

H. E. Brandt

2009-01-01

314

[Computer use in voice analysis: clinical applications  

UK PubMed Central (United Kingdom)

Computers play an important role in voice analysis both in research and in the clinic. We have revised some basic concepts in signal digitization and some of the options present in the different voice analysis systems as: intensity and fundamental frequency measurement, perturbation calculation (jitter and shimmer) and spectrographic analysis. Clinical applications are outlined in conclusion.

Nieto A; del Palacio AJ; Lorenzo FJ; Vegas A; Cobeta I

1995-07-01

315

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

316

Spatially coded backscatter radiography  

International Nuclear Information System (INIS)

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

2007-01-01

317

SIMPLE for industrial radiography  

International Nuclear Information System (INIS)

[en] 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)

2004-01-01

318

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

319

Computer Complex for Analysis of Radiographic Images  

International Science & Technology Center (ISTC)

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

320

Bone X-Ray (Radiography)  

Medline Plus

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

 
 
 
 
321

Bone X-Ray (Radiography)  

Medline Plus

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

322

Computer discriminant analysis of atypical urothelial cells.  

UK PubMed Central (United Kingdom)

Prior computer studies of digitized cell images by the TICAS system have shown that the category of urothelial cells classified visually as atypical may be composed of 2 subgroups, one clustering mainly with benign cells and the other with malignant cells. As a consequence, a visual review of the group of atypical cells was conducted and tested by computer discriminant analysis. The computer classification confirmed the visual reclassification and subdivision of atypical urothelial cells into 2 subgroups, ATY I and ATY II. This is yet another example of feedback from computer diagnosis to visual assessment of cells. The significance of these observations in terms of diagnosis will be the subject of subsequent communications.

Koss LG; Bartels PH; Sychra JJ; Wied GL

1978-09-01

323

An Analysis of Distributed Computer Network Administration  

Directory of Open Access Journals (Sweden)

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

Amit Kumar Sahu; Naveen Hemrajani

2012-01-01

324

Management Waste Of Of Radiography Of Personal Certification Process  

International Nuclear Information System (INIS)

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

2000-01-00

325

Compton radiography, 2  

International Nuclear Information System (INIS)

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

1977-01-01

326

High definition radiography  

International Nuclear Information System (INIS)

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

1976-09-06

327

Nuclear scattering radiography  

International Nuclear Information System (INIS)

Three preliminary publications have described the principle and first results of Nuclear Scattering Radiography (NSR) as a method providing three dimensional information on the density distribution of matter in some structures: phantoms and spinal cord. We will report on a further step achieved by applying the method to a human head conserved in formol

1979-07-06

328

Reference doses for dental radiography.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To establish reference doses for use within dental radiography. DESIGN: Retrospective analysis, single centre. SETTING: UK General Dental Practice, 1995-1998. METHOD: A statistical analysis was performed on the results from NRPB evaluations of dental x-ray equipment within general practice. The third quartile patient entrance dose was determined from 6,344 assessments of intra-oral x-ray equipment. The third quartile dose-width product was determined from 387 assessments of panoramic x-ray equipment. RESULTS: The third quartile patient entrance dose for an adult mandibular molar intra-oral radiograph is 3.9 mGy. The third quartile dose-width product for a standard adult panoramic radiograph is 66.7 mGy mm. CONCLUSION: NRPB recommends the adoption of reference doses of 4 mGy for an adult mandibular molar intra-oral radiograph and 65 mGy mm for a standard adult panoramic radiograph. These reference values can be used as a guide to accepted clinical practice. Where radiography is carried out using doses above these reference values, a thorough review of radiographic practice should be made to either improve techniques, or justify keeping the current techniques. However, attainment of doses at or below the reference values cannot be construed as achievement of optimum performance; further dose reductions below the reference value are still practicable.

Napier ID

1999-04-01

329

Computer aided stress analysis of long bones utilizing computed tomography.  

UK PubMed Central (United Kingdom)

A computer aided analysis method has been developed which utilizes computed tomography (CT) and a finite element (FE) computer program to determine the stress-displacement pattern in a long bone section. The CT data file provides the geometry, the apparent density and the elastic properties for the three-dimensional FE model. A developed pre-processor generates the FE model of a human diaphyseal tibia section which is then analyzed by the SAP IV finite element program. The results obtained are sorted and displayed by a developed post-processor and compared with stresses and deformations from the literature. The model generation method was verified by applying it to a model of simple geometry and boundary conditions, then comparing the results with the analytical solution of the same problem. The convergence behavior of nodal displacements was tested as a function of mesh refinement. This method provides an automatic, versatile, non-invasive and accurate tool of long bone modeling for finite element stress analysis.

Marom SA; Linden MJ

1990-01-01

330

Computer aided stress analysis of long bones utilizing computed tomography.  

Science.gov (United States)

A computer aided analysis method has been developed which utilizes computed tomography (CT) and a finite element (FE) computer program to determine the stress-displacement pattern in a long bone section. The CT data file provides the geometry, the apparent density and the elastic properties for the three-dimensional FE model. A developed pre-processor generates the FE model of a human diaphyseal tibia section which is then analyzed by the SAP IV finite element program. The results obtained are sorted and displayed by a developed post-processor and compared with stresses and deformations from the literature. The model generation method was verified by applying it to a model of simple geometry and boundary conditions, then comparing the results with the analytical solution of the same problem. The convergence behavior of nodal displacements was tested as a function of mesh refinement. This method provides an automatic, versatile, non-invasive and accurate tool of long bone modeling for finite element stress analysis. PMID:2373712

Marom, S A; Linden, M J

1990-01-01

331

MTX data acquisition and analysis computer network  

Energy Technology Data Exchange (ETDEWEB)

For the MTX experiment, we use a network of computers for plasma diagnostic data acquisition and analysis. This multivendor network employs VMS, UNIX, and BASIC based computers connected in a local area Ethernet network. Some of the data is acquired directly into a VAX/VMS computer cluster over a fiber-optic serial CAMAC highway. Several HP-Unix workstations and HP-BASIC instrument control computers acquire and analyze data for the more data intensive or specialized diagnostics. The VAX/VMS system is used for global analysis of the data and serves as the central data archiving and retrieval manager. Shot synchronization and control of data flow are implemented by task-to-task message passing using our interprocess communication system. The system has been in operation during our initial MTX tokamak and FEL experiments; it has operated reliably with data rates typically in the range of 5 Mbytes/shot without limiting the experimental shot rate.

Butner, D.N.; Casper, T.A.; Brown, M.D.; Drlik, M.; Meyer, W.H.; Moller, J.M. (Lawrence Livermore National Laboratory, University of California, Livermore, CA (USA))

1990-10-01

332

MTX data acquisition and analysis computer network  

International Nuclear Information System (INIS)

For the MTX experiment, we use a network of computers for plasma diagnostic data acquisition and analysis. This multivendor network employs VMS, UNIX, and BASIC based computers connected in a local area Ethernet network. Some of the data is acquired directly into a VAX/VMS computer cluster over a fiber-optic serial CAMAC highway. Several HP-Unix workstations and HP-BASIC instrument control computers acquire and analyze data for the more data intensive or specialized diagnostics. The VAX/VMS system is used for global analysis of the data and serves as the central data archiving and retrieval manager. Shot synchronization and control of data flow are implemented by task-to-task message passing using our interprocess communication system. The system has been in operation during our initial MTX tokamak and FEL experiments; it has operated reliably with data rates typically in the range of 5 Mbytes/shot without limiting the experimental shot rate.

1990-01-01

333

Computer graphics in reactor safety analysis  

Energy Technology Data Exchange (ETDEWEB)

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

Fiala, C.; Kulak, R.F.

1989-01-01

334

Industrial radiography on radiographic paper  

International Nuclear Information System (INIS)

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

1977-01-01

335

Computer aided stress analysis of long bones utilizing computer tomography  

International Nuclear Information System (INIS)

A computer aided analysis method, utilizing computed tomography (CT) has been developed, which together with a finite element program determines the stress-displacement pattern in a long bone section. The CT data file provides the geometry, the density and the material properties for the generated finite element model. A three-dimensional finite element model of a tibial shaft is automatically generated from the CT file by a pre-processing procedure for a finite element program. The developed pre-processor includes an edge detection algorithm which determines the boundaries of the reconstructed cross-sectional images of the scanned bone. A mesh generation procedure than automatically generates a three-dimensional mesh of a user-selected refinement. The elastic properties needed for the stress analysis are individually determined for each model element using the radiographic density (CT number) of each pixel with the elemental borders. The elastic modulus is determined from the CT radiographic density by using an empirical relationship from the literature. The generated finite element model, together with applied loads, determined from existing gait analysis and initial displacements, comprise a formatted input for the SAP IV finite element program. The output of this program, stresses and displacements at the model elements and nodes, are sorted and displayed by a developed post-processor to provide maximum and minimum values at selected locations in the model.

1986-01-01

336

Computer analysis of ESR spectra  

International Nuclear Information System (INIS)

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

1993-01-01

337

Quantitative radiography for transient multidimensional, multiphase flows  

International Nuclear Information System (INIS)

As computations of transient, multidimensional, multiphase flows are becoming increasingly more realistic, so increases the demand for their detailed experimental validation. The key in this task is the evolution of flow patterns, and the usual approaches of local measurements are inherently limited in meeting this demand. In this paper, we demonstrate the particular suitability of flash X-ray radiography, and the feasibility of reliably quantifying the radiographs of flow regions of various sizes, from microscopic to rather large scale. (orig.)

1998-01-01

338

Coalescence analysis for evolving foams via optical flow computation on projection image sequences.  

Science.gov (United States)

A novel image-processing procedure is proposed for the analysis of sequences of two-dimensional projection images. Sudden events like the merging of bubbles in an evolving foam can be detected and spatio-temporally located in a given projection image sequence. The procedure is based on optical flow computations extended by a forward-backward check for each time step. Compared with prior methods, efficient suppression of noise or false events is achieved owing to uniform foam motion, and the reliability of detection is thus increased. The applicability of the proposed procedure in combination with synchrotron radiography is illustrated by a series of characteristic studies of foams of different kind. First, the detection of single-bubble collapses in aqueous foams is considered. Second, a spatial distribution of coalescence events in metals foamed in casting molds is estimated. Finally, the structural stability of polymer foams containing admixed solid nanoparticles is examined. PMID:22713878

Myagotin, Anton; Ershov, Alexey; Helfen, Lukas; Verdejo, Raquel; Belyaev, Alexander; Baumbach, Tilo

2012-05-05

339

Coalescence analysis for evolving foams via optical flow computation on projection image sequences.  

UK PubMed Central (United Kingdom)

A novel image-processing procedure is proposed for the analysis of sequences of two-dimensional projection images. Sudden events like the merging of bubbles in an evolving foam can be detected and spatio-temporally located in a given projection image sequence. The procedure is based on optical flow computations extended by a forward-backward check for each time step. Compared with prior methods, efficient suppression of noise or false events is achieved owing to uniform foam motion, and the reliability of detection is thus increased. The applicability of the proposed procedure in combination with synchrotron radiography is illustrated by a series of characteristic studies of foams of different kind. First, the detection of single-bubble collapses in aqueous foams is considered. Second, a spatial distribution of coalescence events in metals foamed in casting molds is estimated. Finally, the structural stability of polymer foams containing admixed solid nanoparticles is examined.

Myagotin A; Ershov A; Helfen L; Verdejo R; Belyaev A; Baumbach T

2012-07-01

340

Discrete computer analysis in petroleum geology  

Energy Technology Data Exchange (ETDEWEB)

Computer analysis must not be resembling on geologist`s work, having its own way because of uncertainty and shortness of geological information even on mature stage of exploration, when our original system of formal discrete computer analysis, realised on {open_quotes}FoxPro for Windows{close_quotes} with not substantial but probabilistic (without ever driving the usual maps) representation of geological situation was used for picking out the sets of best points for exploration drilling in south part of Dheprovsko-Donetzky oil-gas basin.

Zakharian, A.Z.

1995-08-01

 
 
 
 
341

Computer simulation, nuclear techniques and surface analysis  

International Nuclear Information System (INIS)

[en] This article is about computer simulation and surface analysis by nuclear techniques, which are non-destructive. The energy method of analysis for nuclear reactions is used. Energy spectra are computer simulated and compared with experimental data, giving target composition and concentration profile information. Details of prediction stages are given for thick flat target yields. Predictions are made for non-flat targets having asymmetric triangular surface contours. The method is successfully applied to depth profiling of 12C and 18O nuclei in thick targets, by deuteron (d,p) and proton (p,?) induced reactions, respectively. (Author)

2010-01-01

342

Computer simulation, nuclear techniques and surface analysis  

Energy Technology Data Exchange (ETDEWEB)

This article is about computer simulation and surface analysis by nuclear techniques, which are non-destructive. The energy method of analysis for nuclear reactions is used. Energy spectra are computer simulated and compared with experimental data, giving target composition and concentration profile information. Details of prediction stages are given for thick flat target yields. Predictions are made for non-flat targets having asymmetric triangular surface contours. The method is successfully applied to depth profiling of {sup 1}2C and {sup 1}8O nuclei in thick targets, by deuteron (d,p) and proton (p,{alpha}) induced reactions, respectively. (Author)

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

2010-07-01

343

Industrial Radiography Safety in Australia  

International Nuclear Information System (INIS)

The first applications of the imaging capability of X-rays were non-medical. Roentgen produced images of his shotgun, a compass and a set of weights in a closed box to show his colleagues. Prior to 1912, X-rays were used little outside the realms of medicine and dentistry because the X-ray tubes failed under the higher voltages required for industrial purposes. However, that changed in 1913 when high vacuum X-ray tubes designed by Coolidge became available. In 1922, industrial radiography took another step forward with the advent of the 200,000-volt X-ray tube that allowed radiographs of thick steel parts to be produced in a reasonable amount of time. In 1931 the American Society of Mechanical Engineers (ASME) permitted approval of fusion welded pressure vessels by x-ray, which promoted an acceptance and use of the method. That application continues. Radium became the initial gamma ray source for industrial radiography. The material allowed radiography of castings up to 30cm thick. During World War II, industrial radiography grew significantly as part of the US Navy's shipbuilding-program, and in 1946 gamma ray sources such as cobalt 60 and iridium 192 became available. These new sources gained rapid popularity because they emitted more intense radiation than radium and were less expensive. Present state: the majority of industrial radiography techniques have changed little since their inception. An image is captured, processed and analysed for evidence of fault or defect. Today however, the images are of higher quality and greater sensitivity, through the use of better quality films, smaller radiation sources and automated processing. Developments in electronics and computers now allow technicians to create a digital image, enhance it, transmit it or store it indefinitely. The most noticeable change in industrial radiography equipment from the technician's view would be the reduction in weight of the equipment for a given kV output. Never the less it remains cumbersome and often exceeds the prescribed OH and S single person lifting limits. The role of industrial radiography has expanded to inspect not only welds and castings, so that it now includes inspection of assembled and processed goods ranging from automotive air-bags to canned food. It is also used in security systems at airports and other facilities. Almost all these applications use cabinet systems which are rarely the subject of serious radiation incidents or accidents. Gamma ray inspection no longer uses radium. The most common radio-isotopes in use now are Cobalt 60 and Iridium 192. Their freedom from the need for an electrical power supply; their high radiation energy and the ability to place a source in positions of limited physical access, ensures the ongoing attraction of the method. The useful activity ranges of typical sources vary according to their application and the effect on total inspection costs. Common source activities in Australia range between 185 and 370 GBq for Cobalt 60; and between 1500 and 3700 GBq for Iridium 192. Outside Australia however there are recent reports of routine industrial radiography using more than 5500 GBq of Iridium 192. Thus it can be appreciated that any radiation accidents involving these high activity sources have the potential for significant radiation doses. Personal Dose Data: ARPANSA and its predecessor, the Australian Radiation Laboratory, has been providing a personal radiation monitoring service for some time, and releases a summary report every few years (ARPANSA/TR 139, ARL/TR 121, ARL/TR 107). The selected data shown in Table 2 indicate a downward trend in occupational doses received by industrial radiographers working in open site situations, which are potentially the most hazardous. This trend is encouraging, especially when the number of industrial radiographers is increasing. A comparison of the ARPANSA data indicate that whilst the average Australian industrial radiographer's annual dose is higher than the 400 ?Sv average for industrial radiographers in a developed country such as the United Kingdo

2006-01-01

344

Quantitative film radiography  

International Nuclear Information System (INIS)

We have developed a system of quantitative radiography in order to produce quantitative images displaying homogeneity of parts. The materials that we characterize are synthetic composites and may contain important subtle density variations not discernible by examining a raw film x-radiograph. In order to quantitatively interpret film radiographs, it is necessary to digitize, interpret, and display the images. Our integrated system of quantitative radiography displays accurate, high-resolution pseudo-color images in units of density. We characterize approximately 10,000 parts per year in hundreds of different configurations and compositions with this system. This report discusses: the method; film processor monitoring and control; verifying film and processor performance; and correction of scatter effects

1991-01-01

345

Projection radiography and tomography  

International Nuclear Information System (INIS)

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

1980-01-01

346

Patient care in radiography  

Energy Technology Data Exchange (ETDEWEB)

This book focuses on patient care procedures for radiographers. The authors focus on the role of the radiographer as a member of the health care team. The authors report on such topics as communication in patient care: safety, medico-legal considerations, transfer and positioning; physical needs; infection control; medication; CPR standards, acute situations; examination of the GI tract; contrast media; special imaging techniques and bedside radiography.

Ehrlich, R.A.; McCloskey, E.D.

1989-01-01

347

Panoramic dental radiography  

International Nuclear Information System (INIS)

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

1980-01-01

348

Compton radiography, 1  

International Nuclear Information System (INIS)

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

1977-01-01

349

Manual on industrial radiography  

International Nuclear Information System (INIS)

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

1981-01-01

350

Patient care in radiography  

International Nuclear Information System (INIS)

This book focuses on patient care procedures for radiographers. The authors focus on the role of the radiographer as a member of the health care team. The authors report on such topics as communication in patient care: safety, medico-legal considerations, transfer and positioning; physical needs; infection control; medication; CPR standards, acute situations; examination of the GI tract; contrast media; special imaging techniques and bedside radiography

1989-01-01

351

Apparatus for gamma radiography  

International Nuclear Information System (INIS)

[en] 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

352

Introduction to industrial radiography  

International Nuclear Information System (INIS)

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

2008-01-01

353

Computer site threat identification and analysis  

Energy Technology Data Exchange (ETDEWEB)

A major early milestone in achieving a sound comprehensive computer security posture for a given site is the identification of both potential and actual threats, a necessary step in a framework for the overall site risk assessment process. This report addresses some considerations in identifying and differentiating among threats, agents which accomplish threats, and threat impacts. It includes some general rank/order modeling approaches to support a threat analysis and to provide input to a following risk analysis. 22 refs., 10 figs.

Clever, J.J.

1989-01-01

354

COMPUTER ANALYSIS OF PLANAR GAMMA CAMERA IMAGES  

Science.gov (United States)

COMPUTER ANALYSIS OF PLANAR GAMMA CAMERA IMAGES T Martonen1 and J Schroeter2 1Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, U.S. EPA, Research Triangle Park, NC 27711 USA and 2Curriculum in Toxicology, Unive...

355

[Quantitative analysis of circulatory radiograms using computers  

UK PubMed Central (United Kingdom)

A technique of quantitative RCG analysis is proposed and tested. It enables the unbiased evaluation of regional hemodynamics phases and of the relation between blood flow rate in arterial and venous beds. The technique is based on calculating the first derivative of the radiocirculogram. The specially developed program may be executed by the computer (ZBM EC).

Pilipenko NI; Shmets LK; Voloshin PV; Mishchenko TS; Abramovich-Poliakov DK

1984-01-01

356

Neutron radiography of Apollo ordnance  

International Nuclear Information System (INIS)

[en] Neutron radiography played an important role in the successful Apollo missions. Neutron radiography was used, for the first time, on a production basis to examine the internal details of ordnance devices employed in the Apollo Program. Ordnance devices ranged from charges which separated the massive booster stages to those which triggered the release of re-entry parachutes. Discussed are the early developments in neutron radiography and the conversion of this infant nondestructive technology into production capabilities. (Auth.)

1983-01-01

357

JRR-3 neutron radiography facility  

International Nuclear Information System (INIS)

This year, a new neutron radiography facility was completed in the upgraded JRR-3. This facility consists of the thermal neutron radiography facility and the cold neutron radiography facility. It came into operation this March, and its characteristics have subsequently been measured. And its high performance was confirmed. In this paper, outline and characteristics of the facility, examples of utilization and techniques are described. (author).

1992-01-01

358

Study of positioning techniques for radiography  

International Nuclear Information System (INIS)

A good positioning technique is of great importance in radiology in order to obtain accurate diagnostic information and reduce the patient's X-ray exposure. In positioning training, students place the phantom on the table under an X-ray tube, adjust the position of the phantom, and repeat the positioning practices until they can obtain fine diagnostic images. As X-ray films are usually used in radiography, the development of such films is necessary. In this kind of training practice, it takes a great deal of time to obtain the X-ray image at the phantom position. It is desirable for students to perform positioning accurately and to confirm the results of positioning within a short time. In this article, we propose a new positioning training method using digital image processing. First, we scan the skull phantom by CT (computed tomography) and obtain CT images. Next, we measure the positioning information of the phantom under the X-ray equipment by using scene analysis. Then, we develop a method that produces the plane image corresponding to the detected phantom position under the X-ray tube. It is expected that our method will be useful as a teaching device to help in the practice of the positioning techniques for various organs without X-ray exposure and, furthermore, in the development of X-ray films. (author)

2008-01-01

359

Flash x-ray radiography  

International Nuclear Information System (INIS)

[en] In scientific technological field, the flash X-ray radiography has long been known as an useful radiation source for the investigation of high speed phenomena and has been widely applied. This paper introduces the work on flash X- ray radiography in China. That includes: flash X-ray radiography system, portable pulsed X-ray system and powerful pulsed X-ray sources. These equipments have been widely used in the fields of ballistics, detonation and biomedical studies. This paper describes the developments in flash X- ray radiography which includes: flash radiographic biomedical studies, X-ray pulse generators of high repetition rate, tomography and other applications

1988-09-02

360

GafChromic XR-QA film in testing panoramic dental radiography.  

UK PubMed Central (United Kingdom)

The location and field size of the incident X-ray beam in panoramic dental radiography cannot be ascertained visually most of the time. However, these parameters are needed for quality control and dosimetry determination. To alleviate this problem, we tested GafChromic XR-QA film on two panoramic systems. For each system, we used the length of a cross-sectional image of the incident beam and the exposure measurement with a pencil ion chamber to compute the dose-area product. The result was confirmed by direct analysis of a dose distribution on a film. Placement of the ion chamber was determined by the latter images. The GafChromic XR-QA version of radiochromic film has thus been demonstrated to usefully complement a pencil ion chamber in the testing of a panoramic radiography system.

Chu RY; Lam T; Liang Y

2007-01-01

 
 
 
 
361

Risk analysis enhancement via computer applications  

International Nuclear Information System (INIS)

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

1992-01-01

362

[Radiography of the thorax with phospholuminescent screens  

UK PubMed Central (United Kingdom)

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

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

1994-01-01

363

Analysis of cylindrical boron carbide-alumina pellets by neutron radiography technique; Analise de pecas cilindricas de alumina-carbeto de boro pela tecnica de auto-radiografia com neutrons  

Energy Technology Data Exchange (ETDEWEB)

In the present work the boron carbide-alumina sintered pellets chemical composition and physical changes was investigated by the neutron radiography techniques. The green pellets obtained by composition in the 300MPa pressure was then sintered in temperatures and times varying between 1500 to 1700 deg C and 1 to 3 hours, respectively. The mass loss of the pellets determination was carried out, and the results was related to that obtained by micrographs and X-ray analysis patterns examination. A relevant contribution to this search was brought by the neutron radiography. Boron neutron absorbance was utilized to verifying the hypothesis of your depletion of the system, in very severe conditions of sintering. (author)

Oliveira, Fabio Branco Vaz de; Pugliesi, Reynaldo; Andrade, Marcos L.G. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Riella, Humberto Gracher [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Quimica. Lab. de Materiais

1996-07-01

364

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

International Nuclear Information System (INIS)

[en] Purpose: To compare radiography, MR imaging, and chemical analysis in posttraumatic knees. Material and Methods: Ten matched pairs with either isolated partial rupture of the medial collateral ligament or combined medial collateral ligament/anterior cruciate ligament rupture were compared with matched controls 10 years after trauma. Weight-bearing radiographys and MR examinations were compared with proteoglycan fragment concentrations in the joint fluid. Results: The chemical analyses were similar in both trauma groups. The radiographs showed mild signs of arthrosis in half the patients with combined injury. MR images showed almost all injuried knees to have degenerative changes of various degrees in the cartilage and menisci. More frequent and more advanced changes were found after combined injury than after isolated injury (p

1997-01-01

365

Computer analysis of Sprouts with nimbers  

CERN Multimedia

Sprouts is a two-player topological game, invented in 1967 in the University of Cambridge by John Conway and Michael Paterson. The game starts with p spots, and ends in at most 3p-1 moves. The first player who cannot play loses. The complexity of the p-spot game is very high, so that the best hand-checked proof only shows who the winner is for the 7-spot game, and the best previous computer analysis reached p=11. We have written a computer program, using mainly two new ideas. The nimber (also known as Sprague-Grundy number) allows us to compute separately independent subgames; and when the exploration of a part of the game tree seems to be too difficult, we can manually force the program to search elsewhere. Thanks to these improvements, we reached up to p=32. The outcome of the 33-spot game is still unknown, but the biggest computed value is the 47-spot game ! All the computed values support the Sprouts conjecture: the first player has a winning strategy if and only if p is 3, 4 or 5 modulo 6. We have also u...

Lemoine, Julien

2010-01-01

366

Computer imaging software for profile photograph analysis.  

UK PubMed Central (United Kingdom)

OBJECTIVES: To describe a novel calibration technique for photographs of different sizes and to test a new method of chin evaluation in relation to established analysis measurements. DESIGN: A photograph analysis and medical record review of 14 patients who underwent combined rhinoplasty and chin correction at an academic center. Patients undergoing concurrent orthognathic surgery, rhytidectomy, or submental liposuction were excluded. Preoperative and postoperative digital photographs were analyzed using computer imaging software with a new method, the soft tissue porion to pogonion distance, and with established measurements, including the cervicomental angle, the mentocervical angle, and the facial convexity angle. RESULTS: The porion to pogonion distance consistently increased after the chin correction procedure (more in the osseous group). All photograph angle measurements changed toward the established normal range postoperatively. CONCLUSIONS: Surgery for facial disharmony requires artistic judgment and objective evaluation. Although 3-dimensional video analysis of the face seems promising, its clinical use is limited by cost. For surgeons who use computer imaging software, analysis of profile photographs is the most valuable tool. Even when preoperative and postoperative photographs are of different sizes, relative distance comparisons are possible with a new calibration technique using the constant facial landmarks, the porion and the pupil. The porion-pogonion distance is a simple reproducible measurement that can be used along with established soft tissue measurements as a guide for profile facial analysis.

Tollefson TT; Sykes JM

2007-03-01

367

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

Directory of Open Access Journals (Sweden)

Full Text Available OBJETIVO: Avaliar a acurácia da tomografia de alta resolução (TCAR) do tórax em relação à radiografia simples (RX) do tórax no diagnóstico de doença intersticial pulmonar relacionada à esclerose sistêmica (ES). MATERIAIS E MÉTODOS: Foram realizados TCAR e RX de tórax em póstero-anterior e perfil em 34 pacientes com diagnóstico de ES, segundo critérios do Colégio Americano de Reumatologia, e feita comparação entre as prevalências dos achados radiológicos sugestivos de doença intersticial pulmonar encontradas com estes dois métodos de imagem. RESULTADOS: Foram observadas alterações em 31 (91%) das TCAR, enquanto 16 (47%) dos RX de tórax se apresentavam alterados. Os achados mais freqüentes à TCAR foram: linhas septais (74%), faveolamento (56%) e bandas parenquimatosas (26%), localizados predominantemente nas bases pulmonares. Os RX de tórax demonstraram áreas de infiltrado reticular em 32% dos casos e distorção parenquimatosa em 12% dos pacientes. Em 18 (53%) pacientes com RX de tórax normal a TCAR revelou espessamento septal em 55%, vidro fosco em 44%, faveolamento em 38,5% e cistos em 33%. CONCLUSÃO: A TCAR é mais sensível que o RX de tórax para a investigação de envolvimento intersticial pulmonar inicial em pacientes com ES, justificando, em casos incipientes, tratamento com terapia imunossupressora.OBJECTIVE: To compare the accuracy of high-resolution computed tomography (HRCT) with chest radiography in the diagnosis of interstitial lung disease in systemic sclerosis (SSc). MATERIALS AND METHODS: HRCT scans and chest radiographs in postero-anterior and lateral views were performed in 34 patients with systemic sclerosis, according to the American College of Rheumatology preliminary criteria for the diagnosis of SSc. The prevalence of radiological findings suggestive of interstitial lung disease in SSc seen on both imaging methods was compared. RESULTS: Interstitial disease was observed on HRCT images of 31 patients (91%) and in the chest radiographs of 16 patients (47%). The most frequent findings observed on HRCT were septal lines (74%), honeycombing (56%) and parenchymal bands (26%). Chest radiographs showed reticular areas of attenuation in 11 patients (32%) and parenchymal distortion in 12% of the patients. In 18 patients (53%) with normal chest radiographs HRCT showed septal lines in 55%, ground glass in 44%, honeycombing in 38.5% and cysts in 33%. CONCLUSION: HRCT is more sensitive than chest radiography in the evaluation of incipient interstitial lung involvement in patients with SSc and can provide a justification for immunosuppressive therapy in patients with early disease.

Ana Beatriz Cordeiro de Azevedo; Silvana Mangeon Meirelles Guimarães; Wilson Campos Tavares Júnior; Débora Calderaro; Hilton Muniz Leão Filho; Cid Sergio Ferreira; José Nelson Mendes Vieira; Diego Correa de Andrade; Caio Moreira

2005-01-01

368

Computation system for nuclear reactor core analysis  

International Nuclear Information System (INIS)

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

1977-01-01

369

Meaningful statistical analysis of large computational clusters.  

Energy Technology Data Exchange (ETDEWEB)

Effective monitoring of large computational clusters demands the analysis of a vast amount of raw data from a large number of machines. The fundamental interactions of the system are not, however, well-defined, making it difficult to draw meaningful conclusions from this data, even if one were able to efficiently handle and process it. In this paper we show that computational clusters, because they are comprised of a large number of identical machines, behave in a statistically meaningful fashion. We therefore can employ normal statistical methods to derive information about individual systems and their environment and to detect problems sooner than with traditional mechanisms. We discuss design details necessary to use these methods on a large system in a timely and low-impact fashion.

Gentile, Ann C.; Marzouk, Youssef M.; Brandt, James M.; Pebay, Philippe Pierre

2005-07-01

370

New trends in computer ECG analysis.  

UK PubMed Central (United Kingdom)

Electrocardiographic (ECG) processing systems are operational in hospitals, outpatient clinics, primary care, and occupational medicine, and are used for population screening and epidemiologic studies. It appears that computer ECG analysis has been accepted, in spite of not yet performing quite as well as expert readers. The question is whether computerized ECG classification can be further improved. Possible new directions for research are: using information from all available beats, combining knowledge contained in different programs, incorporating knowledge gained in body surface mapping and modeling using information from non-ECG data, and collecting large ECG databases for the assessment of ECG programs. This article reviews these developments.

van Bemmel JH

1996-01-01

371

ASTM activities in neutron radiography  

International Nuclear Information System (INIS)

[en] Neutron radiography emerged from the laboratory into an NDT environment that demanded standards for quality and performance. Many NDT areas were established before the advent of these standards. Neutron radiography, on the other hand, faced immediate pressure to produce standards in the shortest possible period of time. To further complicate matters, neutron radiography began its commercial life in high reliability aerospace applications which demanded rigid controls. In response to this obvious need the American Society for Testing and Materials has provided the formal mechanism for producing these standards since 1971 when Committee E-7 on Nondestructive Testing established section E07.01.02

1975-02-10

372

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background A cautious outlook towards neck injuries has been the norm to avoid missing cervical spine injuries. Consequently there has been an increased use of cervical spine radiography. The Canadian Cervical Spine rule was proposed to reduce unnecessary use of cervical sp...

Rethnam Ulfin; Yesupalan Rajam; Gandham Giri

373

Radiography using radioisotope  

International Nuclear Information System (INIS)

[en] Since work started on the first W 1400 large walking dragline in 1949, quite a number of radiographic techniques have been used employing both x-rays and radioactive isotopes. Initially all internal inspection was done using an x-ray set. Due to the enormous size of the equipment, job was tedious. At first, an iridium-192 4mm x 4mm source was used in conjunction with x-ray equipment for the above job. Very soon confidence in gamma ray techniques was established and radiographic sensitivity achieved was enough to meet job requirements. Ultimately gamma ray sources completely replaced x-ray equipment. This paper highlights the tremendous scope for the application of isotope radiography in vast sophisticated industrial field. (auth.)

1977-02-05

374

Radiography geometry principle  

International Nuclear Information System (INIS)

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

2008-01-01

375

Computational methods for nuclear criticality safety analysis  

International Nuclear Information System (INIS)

Nuclear criticality safety analyses require the utilization of methods which have been tested and verified against benchmarks results. In this work, criticality calculations based on the KENO-IV and MCNP codes are studied aiming the qualification of these methods at the IPEN-CNEN/SP and COPESP. The utilization of variance reduction techniques is important to reduce the computer execution time, and several of them are analysed. As practical example of the above methods, a criticality safety analysis for the storage tubes for irradiated fuel elements from the IEA-R1 research has been carried out. This analysis showed that the MCNP code is more adequate for problems with complex geometries, and the KENO-IV code shows conservative results when it is not used the generalized geometry option. (author)

1992-01-01

376

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

International Nuclear Information System (INIS)

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

2005-01-01

377

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

Energy Technology Data Exchange (ETDEWEB)

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

Michael J. Longo

2005-03-11

378

Axial tomography from digitized real time radiography  

Energy Technology Data Exchange (ETDEWEB)

Axial tomography from digitized real time radiographs provides a useful tool for industrial radiography and tomography. The components of this system are: x-ray source, image intensifier, video camera, video line extractor and digitizer, data storage and reconstruction computers. With this system it is possible to view a two dimensional x-ray image in real time at each angle of rotation and select the tomography plane of interest by choosing which video line to digitize. The digitization of a video line requires less than a second making data acquisition relatively short. Further improvements on this system are planned and initial results are reported.

Zolnay, A.S.; McDonald, W.M.; Doupont, P.A.; McKinney, R.L.; Lee, M.M.

1985-01-18

379

Computational advances in transition phase analysis  

International Nuclear Information System (INIS)

In this paper, historical perspective and recent advances are reviewed on computational technologies to evaluate a transition phase of core disruptive accidents in liquid-metal fast reactors. An analysis of the transition phase requires treatment of multi-phase multi-component thermohydraulics coupled with space- and energy-dependent neutron kinetics. Such a comprehensive modeling effort was initiated when the program of SIMMER-series computer code development was initiated in the late 1970s in the USA. Successful application of the latest SIMMER-II in USA, western Europe and Japan have proved its effectiveness, but, at the same time, several areas that require further research have been identified. Based on the experience and lessons learned during the SIMMER-II application through 1980s, a new project of SIMMER-III development is underway at the Power Reactor and Nuclear Fuel Development Corporation (PNC), Japan. The models and methods of SIMMER-III are briefly described with emphasis on recent advances in multi-phase multi-component fluid dynamics technologies and their expected implication on a future reliable transition phase analysis. (author)

1994-01-01

380

Computer simulation, nuclear techniques and surface analysis  

Directory of Open Access Journals (Sweden)

Full Text Available This article is about computer simulation and surface analysis by nuclear techniques, which are non-destructive. The “energy method of analysis” for nuclear reactions is used. Energy spectra are computer simulated and compared with experimental data, giving target composition and concentration profile information. Details of prediction stages are given for thick flat target yields. Predictions are made for non-flat targets having asymmetric triangular surface contours. The method is successfully applied to depth profiling of 12C and 18O nuclei in thick targets, by deuteron (d,p) and proton (p,?) induced reactions, respectively.Este artículo trata de simulación por ordenador y del análisis de superficies mediante técnicas nucleares, que son no destructivas. Se usa el “método de análisis en energía” para reacciones nucleares. Se simulan en ordenador espectros en energía que se comparan con datos experimentales, de lo que resulta la obtención de información sobre la composición y los perfiles de concentración de la muestra. Se dan detalles de las etapas de las predicciones de espectros para muestras espesas y planas. Se hacen predicciones para muestras no planas que tienen contornos superficiales triangulares asimétricos. Este método se aplica con éxito en el cálculo de perfiles en profundidad de núcleos de 12C y de 18O en muestras espesas a través de reacciones (d,p) y (p,?) inducidas por deuterones y protones, respectivamente.

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

2010-01-01

 
 
 
 
381

Application of SDS gradient polyacrylamide slab gel electrofluoresis to analysis of apolipoprotein mass and radiography of rat lipoproteins  

International Nuclear Information System (INIS)

An application of SDS gradient polyacrylamide slab gel electrophoresis to the analysis of lipoprotein polypeptides is described. The 10-15% polyacrylamide gradient provides a high degree of resolution and sensitivity resulting in a single separation of the major apoproteins which can be easily visualized. When combined with autofluorography, individual protein mass and radioactivity can be determined densitometrically while still retaining excellent resolution. Examples of rat lymph and plasma apolipoproteins are shown, and apparent heterogeneity of certain apoprotein subgroups is described. (author).

1984-01-01

382

Filters used in scoliosis radiography  

Energy Technology Data Exchange (ETDEWEB)

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

Lyons, J.M. (Royal Perth Hospital (Australia))

1984-03-01

383

A Portable Electron Radiography System  

CERN Multimedia

The technique of charged particle radiography has been developed and proven with 800 MeV protons at LANSCE and 24 GeV protons at the AGS. Recent work at Los Alamos National Laboratory in collaboration with the Idaho Accelerator Center has extended this diagnostic technique to electron radiography through the development of an inexpensive and portable electron radiography system. This system has been designed to use 30 MeV electrons to radiograph thin static and dynamic systems. The system consists of a compact 30 MeV pulsed electron linear accelerator coupled to a quadrupole lens magnifier constructed from permanent magnet quadrupoles. The design features and operational characteristics of this radiography system are presented as well as the radiographic performance parameters.

Merrill, Frank E; Harmon, Frank; Hunt, Alan W; King, B J; Morris, Christopher

2005-01-01

384

Euratom neutron radiography working group  

International Nuclear Information System (INIS)

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

1986-01-01

385

A transportable neutron radiography system  

International Nuclear Information System (INIS)

A transportable neutron radiography system, incorporating a 50 mg 252Cf source, has been simulated using the MCNPX code. The materials considered were compatible with the European Union Directive on 'Restriction of Hazardous Substances' (RoHS) 2002/95/EC, hence excluding the use of cadmium and lead. The design was optimized with respect to neutron moderation, shielding and collimation. High density polyethylene was chosen as the material for moderator and also shielding, which was further enhanced with layers of bismuth and borated polyethylene. Variable values for the collimator ratio were calculated. With suitable aperture and collimator design it was possible to optimize the neutron radiography parameters. Beam filters also were treated in order to improve the results. The proposed system has been considered with a wide range of radiography parameters, which are comparable with neutron radiography facilities from low power reactors. (author)

2010-01-01

386

Electronic imaging system for neutron radiography at a low power research reactor  

International Nuclear Information System (INIS)

[en] This paper describes an electronic imaging system for producing real time neutron radiography from a low power research reactor, which will allow inspections of samples with high efficiency, in terms of measuring time and result analysis. This system has been implanted because of its potential use in various scientific and industrial areas where neutron radiography with photographic film could not be applied. This real time system is installed in neutron radiography facility of Argonauta nuclear research reactor, at the Instituto de Engenharia Nuclear of the Comissao Nacional de Energia Nuclear, in Brazil. It is adequate to perform real time neutron radiography of static and dynamic events of samples.

2010-01-01

387

Computational analysis of PKA-balanol interactions.  

UK PubMed Central (United Kingdom)

Protein kinases are important targets for designing therapeutic drugs. This paper illustrates a computational approach to extend the usefulness of a single protein-inhibitor structure in aiding the design of protein kinase inhibitors. Using the complex structure of the catalytic subunit of PKA (cPKA) and balanol as a guide, we have analyzed and compared the distribution of amino acid types near the protein-ligand interface for nearly 400 kinases. This analysis has identified a number of sites that are more variable in amino acid types among the kinases analyzed, and these are useful sites to consider in designing specific protein kinase inhibitors. On the other hand, we have found kinases whose protein-ligand interfaces are similar to that of the cPKA-balanol complex and balanol can be a useful lead compound for developing effective inhibitors for these kinases. Generally, this approach can help us discover new drug targets for an existing class of compounds that have already been well characterized pharmacologically. The relative significance of the charge/polarity of residues at the protein-ligand interface has been quantified by carrying out computational sensitivity analysis in which the charge/polarity of an atom or functional group was turned off/on, and the resulting effects on binding affinity have been examined. The binding affinity was estimated by using an implicit-solvent model in which the electrostatic contributions were obtained by solving the Poisson equation and the hydrophobic effects were accounted for by using surface-area dependent terms. The same sensitivity analysis approach was applied to the ligand balanol to develop a pharmacophoric model for searching new drug leads from small-molecule libraries. To help evaluate the binding affinity of designed inhibitors before they are made, we have developed a semiempirical approach to improve the predictive reliability of the implicit-solvent binding model.

Wong CF; Hünenberger PH; Akamine P; Narayana N; Diller T; McCammon JA; Taylor S; Xuong NH

2001-05-01

388

Computational analysis of PKA-balanol interactions.  

Science.gov (United States)

Protein kinases are important targets for designing therapeutic drugs. This paper illustrates a computational approach to extend the usefulness of a single protein-inhibitor structure in aiding the design of protein kinase inhibitors. Using the complex structure of the catalytic subunit of PKA (cPKA) and balanol as a guide, we have analyzed and compared the distribution of amino acid types near the protein-ligand interface for nearly 400 kinases. This analysis has identified a number of sites that are more variable in amino acid types among the kinases analyzed, and these are useful sites to consider in designing specific protein kinase inhibitors. On the other hand, we have found kinases whose protein-ligand interfaces are similar to that of the cPKA-balanol complex and balanol can be a useful lead compound for developing effective inhibitors for these kinase