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Comparison of methods to estimate water‐equivalent diameter for calculation of patient dose

Modern CT systems seek to evaluate patient‐specific dose by converting the CT dose index generated during a procedure to a size‐specific dose estimate using conversion factors that are related to patient attenuation properties. The most accurate way to measure patient attenuation is to evaluate a fu...

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Autores principales: Daudelin, Andrew, Medich, David, Andrabi, Syed Yasir, Martel, Chris
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6123133/
https://www.ncbi.nlm.nih.gov/pubmed/29981187
http://dx.doi.org/10.1002/acm2.12383
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author Daudelin, Andrew
Medich, David
Andrabi, Syed Yasir
Martel, Chris
author_facet Daudelin, Andrew
Medich, David
Andrabi, Syed Yasir
Martel, Chris
author_sort Daudelin, Andrew
collection PubMed
description Modern CT systems seek to evaluate patient‐specific dose by converting the CT dose index generated during a procedure to a size‐specific dose estimate using conversion factors that are related to patient attenuation properties. The most accurate way to measure patient attenuation is to evaluate a full‐field‐of‐view reconstruction of the whole scan length and calculating the true water‐equivalent diameter (D (w)) using CT numbers; however, due to time constraints, less accurate methods to estimate D (w) using patient geometry measurements are used more widely. In this study we compared the accuracy of D (w) values calculated from three different methods across 35 sample scans and compared them to the true D (w). These three estimation methods were: measurement of patient lateral dimension from a pre‐scan localizer radiograph; measurement of the sum of anteroposterior and lateral dimensions from a reconstructed central slice; and using CT numbers from a central slice only. Using the localizer geometry method, 22 out of 35 (62%) samples estimated D (w) within 20% of the true value. The middle slice attenuation and geometry methods gave estimations within the 20% margin for all 35 samples.
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spelling pubmed-61231332018-09-10 Comparison of methods to estimate water‐equivalent diameter for calculation of patient dose Daudelin, Andrew Medich, David Andrabi, Syed Yasir Martel, Chris J Appl Clin Med Phys Radiation Measurements Modern CT systems seek to evaluate patient‐specific dose by converting the CT dose index generated during a procedure to a size‐specific dose estimate using conversion factors that are related to patient attenuation properties. The most accurate way to measure patient attenuation is to evaluate a full‐field‐of‐view reconstruction of the whole scan length and calculating the true water‐equivalent diameter (D (w)) using CT numbers; however, due to time constraints, less accurate methods to estimate D (w) using patient geometry measurements are used more widely. In this study we compared the accuracy of D (w) values calculated from three different methods across 35 sample scans and compared them to the true D (w). These three estimation methods were: measurement of patient lateral dimension from a pre‐scan localizer radiograph; measurement of the sum of anteroposterior and lateral dimensions from a reconstructed central slice; and using CT numbers from a central slice only. Using the localizer geometry method, 22 out of 35 (62%) samples estimated D (w) within 20% of the true value. The middle slice attenuation and geometry methods gave estimations within the 20% margin for all 35 samples. John Wiley and Sons Inc. 2018-07-07 /pmc/articles/PMC6123133/ /pubmed/29981187 http://dx.doi.org/10.1002/acm2.12383 Text en © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Radiation Measurements
Daudelin, Andrew
Medich, David
Andrabi, Syed Yasir
Martel, Chris
Comparison of methods to estimate water‐equivalent diameter for calculation of patient dose
title Comparison of methods to estimate water‐equivalent diameter for calculation of patient dose
title_full Comparison of methods to estimate water‐equivalent diameter for calculation of patient dose
title_fullStr Comparison of methods to estimate water‐equivalent diameter for calculation of patient dose
title_full_unstemmed Comparison of methods to estimate water‐equivalent diameter for calculation of patient dose
title_short Comparison of methods to estimate water‐equivalent diameter for calculation of patient dose
title_sort comparison of methods to estimate water‐equivalent diameter for calculation of patient dose
topic Radiation Measurements
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6123133/
https://www.ncbi.nlm.nih.gov/pubmed/29981187
http://dx.doi.org/10.1002/acm2.12383
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