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Biomedical subjects

R F Bury

Publications and source records attributed to R F Bury.

15 recordsLinked to original sources
PubMed2001

Towards image quality, beam energy and effective dose optimisation in digital thoracic radiography.

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.

Radiation Dosage↗
PubMed2001

Threshold contrast detail detectability measurement of the fluoroscopic image quality of a dynamic solid-state digital x-ray image detector.

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.

Biophysical Phenomena↗
PubMed2000

Initial technical and clinical evaluation of a new universal image receptor system.

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.

Equipment Design↗
PubMed1998

Technical report: Initial experiences with an experimental solid-state universal digital X-ray image detector.

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.

Cecum↗
PubMed1998

Imaging the thyroid.

Thyroid imaging has historically relied heavily on scintigraphy, although, not surprisingly in view of the superficial position of the gland, ultrasound has assumed an increasingly prominent role in recent years. The other cross-sectional imaging modalities can also be useful, and the emergence of new radiopharmaceuticals and the increasingly central role of fine needle aspiration cytology have further added to the range of diagnostic techniques available. This review attempts to summarize the current state of knowledge, and makes some suggestions for the most efficient use of imaging resources in the investigation of thyroid disease.

Goiter↗
PubMed1998

Reporting requirements for skeletal digital radiography: comparison of soft-copy and hard-copy presentation.

PURPOSE: To assess diagnostic performance and reader preference when reporting results from digital hard-copy and two soft-copy formats of skeletal digital radiography. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Bone and Bones↗
PubMed1993

Out-of-hours scintigraphy: a survey of current practice.

A questionnaire was sent to 221 nuclear medicine departments in the UK asking about their staffing and work patterns. In particular, we wanted to know how many of them offered an on-call service. In those cases where departments wished to offer this service but did not do so, they were asked what was stopping them. Replies were received from 150 departments, a response rate of 68%. Of these, 43 (29%) offered an on-call service, although only 21 (14%) performed ten or more out-of-hours scans in an average year. The examinations most commonly offered were lung scans, localization of gastrointestinal bleeding and renography. In those centres wishing to offer an on-call service but which were unable to do so, limitation of resources was the reason most frequently advanced. Lack of clinical demand was the factor most often quoted by those not wishing to extend their service. The issue of emergency scintigraphy is discussed in the light of these results.

Attitude of Health Personnel↗
PubMed1989

Bone scintigraphy in the evaluation of ejection injuries.

The Royal Air Force (RAF) experience on local back injury with all ejection seats is that 50% have vertebral fractures on radiographic examination, with or without symptoms. These aviators are placed under the care of an orthopedic specialist and restricted from flying duties for 3 months or more. About half of the remainder demonstrate positive bone scans. Until recently, RAF policy was to treat these individuals the same as those with radiographically defined fractures. The author recommends this group of pilots be examined by orthopedic surgeons, and reviewed annually to assess long-term sequelae. Meanwhile, if asymptomatic, they are allowed to return to flying duties. The RAF recently incorporated most of these recommendations into a policy change.

Aerospace Medicine↗
PubMed1987

Emphysematous gastritis after acute pancreatitis.

A case of emphysematous gastritis associated with extensive gastric infarction after acute pancreatitis and acute renal failure is described. This complication was diagnosed on a plain abdominal radiograph and confirmed endoscopically. Extensive gastric and hepatic infarction was seen at necropsy.

Acute Disease↗