Results 271 to 280 of about 1,079,802 (320)
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Physica medica (Testo stampato), 2020
PURPOSE This study aimed to compare two methods of assessing the half-value layer (HVL) for computed tomography scanners in a single-rotation technique with and without lead apertures (SRTLA / SRT).
A. Fukuda +5 more
semanticscholar +1 more source
PURPOSE This study aimed to compare two methods of assessing the half-value layer (HVL) for computed tomography scanners in a single-rotation technique with and without lead apertures (SRTLA / SRT).
A. Fukuda +5 more
semanticscholar +1 more source
Uncertainties in half value layer determination in mammography
AIP Conference Proceedings, 2016A critical analysis of the methodologies for evaluating the x-ray half value layer was conducted. Experimental data were fitted by using MATLAB curve fitting toolbox, to an exponential function. Half value layer and its uncertainties were determined directly from the parameter of the fitted function.
S. Mijović +3 more
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Rapid Determination of the Half-Value Layer of Radiographic X-Ray Machines
Radiology, 1973Many governmental agencies require verification of the collimator alignment and the half-value layer (HVL). The authors propose a method by which the widely used film technique may be extended to measurement of the HVL. The method is validated and its accuracy verified by measurements of 25 radiographic units.
L, Stanton +3 more
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A Nomogram for the Determination of Half-value Layers
The British Journal of Radiology, 1936Although a statement of the half-value layer alone does not specify the X-ray quality of the radiation in the sense of the accepted definition, it is often sufficient to characterise the radiation. An analysis of the results of several workers shows that a statement of exciting voltage, filtration and type of generator (constant—or pulsating—potential)
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On the Adequacy of Half-value Layer as a Criterion of X-ray Quality in the Calibration of Dosemeters
The British Journal of Radiology, 1960Five thimble ionization chambers were compared with a free-air chamber using X rays produced at 20 to 55 kV with half-value layers between 0·05 and 0·20 mm Al. One chamber showed a difference of nearly 4 per cent in its correction factor for beams of the same H.V.L. produced at 20 and 55 kV. With this single exception H.V.L.
N M, PROCTER, J R, GREENING
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Oral Surgery, Oral Medicine, Oral Pathology, 1966
Abstract It appears that further attempts to achieve reduction in radiation dose through the use of higher HVL, increased filtration, and higher voltage will not be productive. It is suggested that optimum levels for present equipment and films lie within the ranges now in use.
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Abstract It appears that further attempts to achieve reduction in radiation dose through the use of higher HVL, increased filtration, and higher voltage will not be productive. It is suggested that optimum levels for present equipment and films lie within the ranges now in use.
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Characterization of X-ray Beam for Half and Quarter Value Layers
Annals of Computational Physics and Material ScienceIntroduction: The aim of this work is to assess the penetrating ability of an X-ray beam through a specific material, in conditions of narrow-beam geometry. Materials and Methods: During the experiment, samples were switched with the X-ray tube turned off, and the primary intensity of the unshielded X-ray beam (fixed 2.5mm shielding) was measured ...
Khazratov Diyor +3 more
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A Technic for Cross-Calibration of X-Ray Units Utilizing Half-Value-Layer Determinations
Radiology, 1961In radiographic installations of more than one x-ray unit the need to reproduce a film technic with different units makes it necessary that they be cross-calibrated. In standard practice the establishment of a film technic requires that visual examination be made of representative films for various anatomical structures.
L, PAPE, S, BAKER, H L, GILDENHORN
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Half-value layer measurement using a radiochromic film for QA and QC
2008Purpose Methods and Materials Results ...
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