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Data for Modelling the Penumbra in Computed Tomography
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Kueh, Audrey, Warnett, J. W., Gibbons, Gregory John, Brettschneider, Julia, Nichols, Thomas E., Williams, M. A. (Mark A.) and Kendall, W. S. (2016) Data for Modelling the Penumbra in Computed Tomography. [Dataset]
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Archive (ZIP) (Zip file containing dataset files and description)
CeramicRod.zip - Published Version Download (129Mb) |
Official URL: http://wrap.warwick.ac.uk/78867
Abstract
Background:
In computed tomography (CT), the spot geometry is one of the main sources of error in CT images. Since X-rays do not arise from a point source, artefacts are produced. In particular there is a penumbra effect, leading to poorly defined edges within a reconstructed volume. Penumbra models can be simulated given a fixed spot geometry and the known experimental setup.
Objective:
This paper proposes to use a penumbra model, derived from Beer’s law, both to confirm spot geometry from penumbra data, and to quantify blurring in the image. Methods: Two models for the spot geometry are considered; one consists of a single Gaussian spot, the other is a mixture model consisting of a Gaussian spot together with a larger uniform spot. Results: The model consisting of a single Gaussian spot has a poor fit at the boundary. The mixture model (which adds a larger uniform spot) exhibits a much improved fit. The parameters corresponding to the uniform spot are similar across all powers, and further experiments suggest that the uniform spot produces only soft X-rays of relatively low-energy.
Conclusions:
Thus, the precision of radiographs can be estimated from the penumbra effect in the image. The use of a thin copper filter reduces the size of the effective penumbra.
Item Type: | Dataset | ||||||
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Subjects: | R Medicine > RC Internal medicine | ||||||
Divisions: | Faculty of Science, Engineering and Medicine > Science > Statistics Faculty of Science, Engineering and Medicine > Engineering > WMG (Formerly the Warwick Manufacturing Group) |
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Type of Data: | Zipfile containing TIFF images, and textfiles giving description and R code for reading TIFF files into R | ||||||
Library of Congress Subject Headings (LCSH): | Tomography -- Data processing | ||||||
Publisher: | University of Warwick, Department of Physics | ||||||
Official Date: | 26 April 2016 | ||||||
Dates: |
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Collection date: |
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Status: | Not Peer Reviewed | ||||||
Publication Status: | Published | ||||||
Media of Output (format): | .txt | ||||||
Access rights to Published version: | Open Access (Creative Commons) | ||||||
Description: | Penumbra data These data files correspond to the data discussed in Kueh et al (2016). A 3mm ceramic rod was placed centrally on the manipulator in an approximately File structure 0.177s_44W: 0.25s_30.6W: 0.354s_21W: 0.5s_14.6W: 0.708s_9.6W: 1.415s_4W: 1s_6.4W: |
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Date of first compliant deposit: | 3 May 2016 | ||||||
Date of first compliant Open Access: | 3 May 2016 | ||||||
RIOXX Funder/Project Grant: |
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