Robert F. Bury

ECRI Institute, Плимут, Pennsylvania, United States

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Publications (13)27.23 Total impact

  • J H Launders · AR Cowen · R F Bury · P Hawkridge
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    ABSTRACT: This paper outlines how objective measurements of both image quality, in terms of signal-to-noise ratio, and effective dose may be used as tools to find the optimum kVp range for a digital chest radiography system. Measurements were made with Thoravision, an amorphous selenium-based digital chest X-ray system. The entrance surface dose and the effective dose to an anthropomorphic chest phantom were determined demonstrating how effective dose is related to beam quality. The image quality was measured using detective quantum efficiency, threshold contrast and a radiologist preference trial involving 100 patients. The results show that, despite the fact that the entrance surface dose decreases as the kVp increases, the effective dose, a better measure of the risk, reaches a minimum value between 90 and 110 kVp; however, the image quality decreases as the kVp increases. In this study the optimum kVp for chest radiography, using a selenium-based radiography system, is in the range 90-110 kVp. This is contrary to the 120- to 150-kVp range that is commonly used. Also, this study shows how objective measurements can be used to optimise radiographic technique without prolonged patient trials.
    European Radiology 02/2001; 11(5):870-5. DOI:10.1007/s003300000525 · 4.34 Impact Factor
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    ABSTRACT: Solid-state digital x-ray imaging detectors of flat-panel construction will play an increasingly important role in future medical imaging facilities. Solid-state detectors that will support both dynamic (including fluoroscopic) and radiographic image recording are under active development. The image quality of an experimental solid-state digital x-ray image detector operating in a continuous fluoroscopy mode has been investigated. The threshold contrast detail detectability (TCDD) technique was used to compare the fluoroscopic imaging performance of an experimental dynamic solid-state digital x-ray image detector with that of a reference image intensifier television (IITV) fluoroscopy system. The reference system incorporated Plumbicon TV. Results were presented as a threshold detection index, or H(T)(A), curves. Measurements were made over a range of mean entrance air kerma (EAK) rates typically used in conventional IITV fluoroscopy. At the upper and mid EAK rate range (440 and 220 nGy/s) the solid-state detector outperformed the reference IITV fluoroscopy system as measured by TCDD performance. At the lowest measured EAK rate (104 nGy/s), the solid-state detector produces slightly inferior TCDD performance compared with the reference system. Although not statistically significant at this EAK rate, the difference will increase as EAK is lowered further. Overall the TCDD results and early clinical experiences support the proposition that a current design of dynamic solid-state detector produces image quality competitive with that of modern IITV fluoroscopy systems. These findings encourage the development of compact and versatile universal x-ray imaging systems based upon solid-state detector technology to support R & F and vascular/interventional applications.
    Medical Physics 02/2001; 28(1):11-5. DOI:10.1118/1.1312814 · 3.01 Impact Factor
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    ABSTRACT: The aim of this study was to evaluate the physical performance of an experimental flat-panel digital X-ray detector plate (FDXD), and to assess its clinical potential in radiographic and fluoroscopic mode. The efficiency of the detector was assessed by calculating the low-frequency detective quantum efficiency (DQE(0)), and a measure of image quality was obtained using a threshold contrast detail detectability (TCDD) test object. A range of clinical examinations were also carried out, and the results reviewed by members of the radiology staff. The DQE(0) of the system was calculated to be almost 75%, compared with a value of approximately 20 % for modern computed radiography equipment, offering the potential for increased image quality or significant dose reduction. Measurements using the TCDD test object demonstrated a corresponding advantage for the FDXD in image quality and dose efficiency. Clinical studies are producing radiographic results which are at least the equal of the best currently available digital technology, and a limited number of examinations using fluoroscopic mode at 25 frames per second have been equally encouraging. Equipment using FDXD technology could potentially fulfill all the radiographic and fluoroscopic requirements of the digital department, with improved image quality and dose efficiency.
    European Radiology 02/2000; 10(12):1983-7. DOI:10.1007/s003300000531 · 4.34 Impact Factor
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    ABSTRACT: Advanced technical investigations, including DQE measurements and threshold contrast detail-detectability experiments, have been performed in order to demonstrate the superior image quality of an experimental flat dynamic X-ray image detector (FDXD) system. The dose efficiencies throughout a range of dose levels used in fluoroscopic and radiographic applications have been measured and are presented. Together with the results of a range of clinical patient examinations, the results of the technical investigations fully confirm earlier expectations in terms of increased image quality and improved dose efficiency with respect to current imaging modalities. Several mixed applications performed with the FDXD system are presented including those where subtraction techniques were used. The dynamic aspects of the FDXD system are discussed in detail. In the fluoroscopic mode, images have been acquired with a dose-rate as low as 5 nGy per image using a frame rate of approx. 25 fps. Low dose fluoroscopic images will be presented and it will be confirmed that low readout noise of the detection system facilitates the clinical acceptability of the images, even without applying any noise reduction algorithms. Post-processing algorithms for exposures will also be discussed. It can be concluded that the results of the technical measurements, together with the clinical examinations, prove that in areas regarding dose efficiency and image quality, this new detector technology is superior to the current X-ray modalities in many aspects.
    Proceedings of SPIE - The International Society for Optical Engineering 05/1999; DOI:10.1117/12.349507 · 0.20 Impact Factor
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    ABSTRACT: This paper presents a brief technical evaluation and first review of clinical experiences with an experimental direct digital X-ray image detector designed to support both dynamic and snap-shot imaging. Derivatives of this type of image detector can potentially fulfil the majority of the fluoroscopic and radiographic imaging requirements of clinical radiology departments, and initial results suggest that imaging systems using the new technology will provide a high quality dose-efficient solution to the search for a universal digital X-ray image detector.
    Clinical Radiology 01/1999; 53(12):923-8. · 1.66 Impact Factor
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    ABSTRACT: This paper presents a brief technical evaluation and first review of clinical experiences with an experimental direct digital X-ray image detector designed to support both dynamic and snap-shot imaging. Derivatives of this type of image detector can potentially fulfil the majority of the fluoroscopic and radiographic imaging requirements of clinical radiology departments, and initial results suggest that imaging systems using the new technology will provide a high quality dose-efficient solution to the search for a universal digital X-ray image detector.
    Clinical Radiology 12/1998; 53(12):923-928. DOI:10.1016/S0009-9260(98)80225-0 · 1.66 Impact Factor
  • Radiation Protection Dosimetry 11/1998; 80(1):279-282. DOI:10.1093/oxfordjournals.rpd.a032523 · 0.86 Impact Factor
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    ABSTRACT: A clinical imaging system based upon an amorphous-Silicon (a- Si) flat dynamic (digital) X-ray image detector (FDXD) has been developed. The objectives of this experimental set-up were to determine the physical image quality and to establish the clinical feasibility of a flat-panel x-ray detector for radiography and fluoroscopy (R&F) applications. The FDXD acquires dynamic X-ray images at high frame rates in both continuous and pulsed fluoroscopic modes, lower frame rate exposures and single shots. The system has been installed in a clinical research room at The General Infirmary, Leeds (UK) and is being evaluated in a variety of universal R&F contrast medium aided examinations, including barium swallows, meals and enema examinations. In addition, general radiographic examinations have been performed. Both the established benefits and possible drawbacks of this type of system, together with the potential solutions, are discussed in this paper. Approach, design and set-up of the system are presented, and the dose efficiency and image quality achieved in clinical operation are explained. The technical and medical phantom images have been evaluated and analyzed. The results of the clinical examinations in mixed applications are discussed. The results of the measurements and examinations performed to date on this experimental FDXD system confirm the potential of this new type of digital X-ray image detector.
    Proceedings of SPIE - The International Society for Optical Engineering 07/1998; DOI:10.1117/12.317038 · 0.20 Impact Factor
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    ABSTRACT: To assess diagnostic performance and reader preference when reporting results from digital hard-copy and two soft-copy formats of skeletal digital radiography. The data comprised hand radiographs of patients undergoing renal dialysis. Normal hand radiographs obtained in trauma patients were assessed as control images. One hundred fifteen images acquired with a photostimulable-phosphor computed radiography system were analyzed. Image selection and initial assessment were by consensus of two experienced radiologists, who graded the radiographic changes of hyperparathyroidism with the Ritz scoring system. The images were then presented to four readers in three formats: hard-copy output and soft-copy presentations at 2K2 and 1K2 resolutions. These readers scored pathologic change and image preference. The results were analyzed with the receiver operating characteristic technique. There was a significant improvement in diagnostic performance for both soft-copy formats relative to the hard-copy format (P < .001). No significant difference in diagnostic performance was found between the two soft-copy formats. There was a significant preference for both soft-copy formats relative to the hard-copy format (P < .01), with the 2K2 soft-copy images preferred to the 1K2 images (P < .01). Soft-copy reporting can provide superior diagnostic performance even for images viewed at a modest (1K2) resolution. The lack of difference between the two soft-copy formats has important economic implications with respect to departmental hardware requirements.
    Radiology 04/1998; 207(1):249-54. DOI:10.1148/radiology.207.1.9530323 · 6.21 Impact Factor
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    ABSTRACT: This paper describes the current status of our program of work in the area of digital image enhancement using wavelet-based multi-scale processing. We are developing an all-wavelet image processing algorithm to enhance the quality of direct digital thorax images, by the manipulation of the data within scale-specific sub-bands. This method avoids the presentation compromises which may result from the global application of unsharp mask based image enhancement methods which are commonly used in medical imaging. This is achieved by applying specific processing to image components according to their scale. In particular contrast enhancement, de-noising and sharpening stages are all tailored to the noise and feature characteristics of Thoravision digital chest X-ray images. Whilst our experiments to date convince us that processing digital X-ray images within the wavelet domain is a useful tool for improving diagnostic image quality, our concerns now focus on the subtlety of this processing, since it can be prone to artefact generation if applied incorrectly. We are also interested in optimising the way in which wavelet based image enhancement must be presented to our clinical colleagues to meet their diagnostic needs
    Image Processing and Its Applications, 1997., Sixth International Conference on; 08/1997
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    European Radiology 10/1996; 6(5):S89. · 4.34 Impact Factor
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    ABSTRACT: The issue of the spatial resolution required in order to present diagnostic quality digital images, especially for softcopy reporting, has received much attention over recent years. The aim of this study was to compare the diagnostic performance reporting from hardcopy and optimized softcopy image presentations. One-hundred-fifteen radiographs of the hand acquired on a photostimulable phosphor computed radiography (CR) system were chosen as the image material. The study group was taken from patients who demonstrated subtle erosions of the bone in the digits. The control group consisted of radiologically normal bands. The images were presented in three modes, the CR system's hardcopy output, and softcopy presentations at full and half spatial resolutions. Four consultant radiologists participated as observers. Results were analyzed using the receiver operating characteristic (ROC) technique, and showed a statistically significant improvement in observer performance for both softcopy formats, when compared to the hardcopy presentation. However, no significant difference in observer performance was found between the two softcopy presentations. We therefore conclude that, with appropriate attention to the processing and presentation of digital image data, softcopy reporting can, for most examinations, provide superior diagnostic performance, even for images viewed at modest (1 k2) resolutions.
    Proceedings of SPIE - The International Society for Optical Engineering 04/1996; DOI:10.1117/12.238461 · 0.20 Impact Factor
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    ABSTRACT: Photostimulable phosphor computed radiography (CR) is becoming an increasingly popular image acquisition system. The acceptability of this technique, both diagnostically, ergonomically and economically is highly influenced by the method by which the image data is presented to the user. Traditional CR systems utilize an 11' by 14' film hardcopy format, and can place two images per exposure onto this film, which does not correspond to sizes and presentations provided by conventional techniques. It is also the authors' experience that the image enhancement algorithms provided by traditional CR systems do not provide optimal image presentation. An alternative image enhancement algorithm was developed, along with a number of hardcopy formats, designed to match the requirements of the image reporting process. The new image enhancement algorithm, called dynamic range reduction (DRR), is designed to provide a single presentation per exposure, maintaining the appearance of a conventional radiograph, while optimizing the rendition of diagnostically relevant features within the image. The algorithm was developed on a Sun SPARCstation, but later ported to a Philips' EasyVisionRAD workstation. Print formats were developed on the EasyVision to improve the acceptability of the CR hardcopy. For example, for mammographic examinations, four mammograms (a cranio-caudal and medio-lateral view of each breast) are taken for each patient, with all images placed onto a single sheet of 14' by 17' film. The new composite format provides a more suitable image presentation for reporting, and is more economical to produce. It is the use of enhanced image processing and presentation which has enabled all mammography undertaken within the general infirmary to be performed using the CR/EasyVisionRAD DRR/3M 969 combination, without recourse to conventional film/screen mammography.
    Proceedings of SPIE - The International Society for Optical Engineering 03/1996; DOI:10.1117/12.236857 · 0.20 Impact Factor