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4D CT image acquisition errors in SBRT of liver identified using correlation

In the AAPM Report 80,(() (1) ()) the imaging modality of 4D CT and respiration‐correlated CT was declared a “promising solution for obtaining high‐quality CT data in the presence of respiratory motion”. To gather anatomically correct data over time, the existence of correlation between the internal...

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Autores principales: Szegedi, Martin, Sarkar, Vikren, Rassiah‐Szegedi, Prema, Wang, Brian, Huang, Y.Jessica, Zhao, Hui, Salter, Bill
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5716128/
https://www.ncbi.nlm.nih.gov/pubmed/22231209
http://dx.doi.org/10.1120/jacmp.v13i1.3564
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author Szegedi, Martin
Sarkar, Vikren
Rassiah‐Szegedi, Prema
Wang, Brian
Huang, Y.Jessica
Zhao, Hui
Salter, Bill
author_facet Szegedi, Martin
Sarkar, Vikren
Rassiah‐Szegedi, Prema
Wang, Brian
Huang, Y.Jessica
Zhao, Hui
Salter, Bill
author_sort Szegedi, Martin
collection PubMed
description In the AAPM Report 80,(() (1) ()) the imaging modality of 4D CT and respiration‐correlated CT was declared a “promising solution for obtaining high‐quality CT data in the presence of respiratory motion”. To gather anatomically correct data over time, the existence of correlation between the internal organ movement and an external surrogate has to be assumed. For the in‐house evaluation of such correlation, we retrospectively analyzed 21 four‐dimensional computer tomography (4D CT) scans of five patients, out of which the artifacts experienced in three patients are shown here. To provide context and a baseline for the analysis of patient motion, a real‐tissue liver phantom was used with a solid water block and liver tissue. The superior–inferior motion of fiducials in phantom and patients was correlated to the recorded anterior–posterior motion of an external surrogate marker on the chest. The use of a solid water block yielded a measurable correlation coefficient of 0.98 or better using a sinusoidal animation pattern. With sinusoidally‐animated liver tissue, the minimum correlation observed was 0.96. Comparing this to retrospective patient data, we found three cases of a change in the correlation coefficient, or simply a low correlation. The source of this low correlation was investigated by careful examination of the breathing traces and the CT‐phase assignments used to reconstruct the datasets. Consequences of nonregular breathing are elaborated on. We demonstrate the impact of wrong phase assignments and missing image information in the 4D CT phase sampling processes. We also show how daily patient‐based correlation analysis can indicate changes in breathing traces, which can be significant enough to decrease, or completely eliminate, previously existing correlation. PACS numbers: 87.57.‐s, 87.57.Q‐, 87.57.cp, 87.57.N‐, 87.55.Qr
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spelling pubmed-57161282018-04-02 4D CT image acquisition errors in SBRT of liver identified using correlation Szegedi, Martin Sarkar, Vikren Rassiah‐Szegedi, Prema Wang, Brian Huang, Y.Jessica Zhao, Hui Salter, Bill J Appl Clin Med Phys Radiation Oncology Physics In the AAPM Report 80,(() (1) ()) the imaging modality of 4D CT and respiration‐correlated CT was declared a “promising solution for obtaining high‐quality CT data in the presence of respiratory motion”. To gather anatomically correct data over time, the existence of correlation between the internal organ movement and an external surrogate has to be assumed. For the in‐house evaluation of such correlation, we retrospectively analyzed 21 four‐dimensional computer tomography (4D CT) scans of five patients, out of which the artifacts experienced in three patients are shown here. To provide context and a baseline for the analysis of patient motion, a real‐tissue liver phantom was used with a solid water block and liver tissue. The superior–inferior motion of fiducials in phantom and patients was correlated to the recorded anterior–posterior motion of an external surrogate marker on the chest. The use of a solid water block yielded a measurable correlation coefficient of 0.98 or better using a sinusoidal animation pattern. With sinusoidally‐animated liver tissue, the minimum correlation observed was 0.96. Comparing this to retrospective patient data, we found three cases of a change in the correlation coefficient, or simply a low correlation. The source of this low correlation was investigated by careful examination of the breathing traces and the CT‐phase assignments used to reconstruct the datasets. Consequences of nonregular breathing are elaborated on. We demonstrate the impact of wrong phase assignments and missing image information in the 4D CT phase sampling processes. We also show how daily patient‐based correlation analysis can indicate changes in breathing traces, which can be significant enough to decrease, or completely eliminate, previously existing correlation. PACS numbers: 87.57.‐s, 87.57.Q‐, 87.57.cp, 87.57.N‐, 87.55.Qr John Wiley and Sons Inc. 2012-01-05 /pmc/articles/PMC5716128/ /pubmed/22231209 http://dx.doi.org/10.1120/jacmp.v13i1.3564 Text en © 2012 The Authors. This is an open access article under the terms of the Creative Commons Attribution (http://creativecommons.org/licenses/by/3.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Radiation Oncology Physics
Szegedi, Martin
Sarkar, Vikren
Rassiah‐Szegedi, Prema
Wang, Brian
Huang, Y.Jessica
Zhao, Hui
Salter, Bill
4D CT image acquisition errors in SBRT of liver identified using correlation
title 4D CT image acquisition errors in SBRT of liver identified using correlation
title_full 4D CT image acquisition errors in SBRT of liver identified using correlation
title_fullStr 4D CT image acquisition errors in SBRT of liver identified using correlation
title_full_unstemmed 4D CT image acquisition errors in SBRT of liver identified using correlation
title_short 4D CT image acquisition errors in SBRT of liver identified using correlation
title_sort 4d ct image acquisition errors in sbrt of liver identified using correlation
topic Radiation Oncology Physics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5716128/
https://www.ncbi.nlm.nih.gov/pubmed/22231209
http://dx.doi.org/10.1120/jacmp.v13i1.3564
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