Assessment of the effects of CT dose in averaged x-ray CT images of a dose-sensitive polymer gel

Kairn, T., Kakakhel, M.B., Johnston, H., Jirasek, A., & Trapp, J.V. (2015) Assessment of the effects of CT dose in averaged x-ray CT images of a dose-sensitive polymer gel. Journal of Physics : Conference Series, 573, 012075.

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The signal-to-noise ratio achievable in x-ray computed tomography (CT) images of polymer gels can be increased by averaging over multiple scans of each sample. However, repeated scanning delivers a small additional dose to the gel which may compromise the accuracy of the dose measurement. In this study, a NIPAM-based polymer gel was irradiated and then CT scanned 25 times, with the resulting data used to derive an averaged image and a "zero-scan" image of the gel. Comparison between these two results and the first scan of the gel showed that the averaged and zero-scan images provided better contrast, higher contrast-to- noise and higher signal-to-noise than the initial scan. The pixel values (Hounsfield units, HU) in the averaged image were not noticeably elevated, compared to the zero-scan result and the gradients used in the linear extrapolation of the zero-scan images were small and symmetrically distributed around zero. These results indicate that the averaged image was not artificially lightened by the small, additional dose delivered during CT scanning. This work demonstrates the broader usefulness of the zero-scan method as a means to verify the dosimetric accuracy of gel images derived from averaged x-ray CT data.

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ID Code: 80033
Item Type: Journal Article
Refereed: Yes
Keywords: gel dosimetry, CT, signal to noise, ct gel dosimetry
DOI: 10.1088/1742-6596/573/1/012075
ISSN: 1742-6596
Subjects: Australian and New Zealand Standard Research Classification > PHYSICAL SCIENCES (020000) > OTHER PHYSICAL SCIENCES (029900) > Medical Physics (029903)
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2015 Institute of Physics Publishing
Copyright Statement: Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution
of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Published under licence by IOP Publishing Ltd 1
Deposited On: 14 Jan 2015 05:59
Last Modified: 06 Sep 2016 03:16

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