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Technical evaluation of TomoTherapy automatic roll correction
The TomoTherapy Hi·Art System allows the application of rotational corrections as a part of the pretreatment image guidance process. This study outlines a custom method to perform an end‐to‐end evaluation of the TomoTherapy Hi·Art roll correction feature. A roll‐sensitive plan was designed and deliv...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5690141/ https://www.ncbi.nlm.nih.gov/pubmed/26103471 http://dx.doi.org/10.1120/jacmp.v16i3.4836 |
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author | Laub, Steve Snyder, Michael Burmeister, Jay |
author_facet | Laub, Steve Snyder, Michael Burmeister, Jay |
author_sort | Laub, Steve |
collection | PubMed |
description | The TomoTherapy Hi·Art System allows the application of rotational corrections as a part of the pretreatment image guidance process. This study outlines a custom method to perform an end‐to‐end evaluation of the TomoTherapy Hi·Art roll correction feature. A roll‐sensitive plan was designed and delivered to a cylindrical solid water phantom to test the accuracy of roll corrections, as well as the ability of the automatic registration feature to detect induced roll. Cylindrical target structures containing coaxial inner avoidance structures were placed adjacent to the plane bisecting the phantom and 7 cm laterally off central axis. The phantom was positioned at isocenter with the target‐plane parallel to the couch surface. Varying degrees of phantom roll were induced and dose to the targets and inner avoidance structures was measured using Kodak EDR2 films placed in the target‐plane. Normalized point doses were compared with baseline (no roll) data to determine the sensitivity of the test and the effectiveness of the roll correction feature. Gamma analysis comparing baseline, roll‐corrected, and uncorrected films was performed using film analysis software. MVCT images were acquired prior to plan delivery. Measured roll was compared with induced roll to evaluate the automatic registration feature's ability to detect rotational misalignment. Rotations beyond 0.3° result in statistically significant deviation from baseline point measurements. Gamma pass rates begin to drop below 90% at approximately 0.5° induced rotation at [Formula: see text] and between 0.2° and 0.3° for 2%/2 mm. With roll correction applied, point dose measurements for all rotations are indistinguishable from baseline, and gamma pass rates exceed 96% when using 3% and 3 mm as evaluation criteria. Measured roll via the automatic registration algorithm agrees with induced rotation to within the test sensitivity for nearly all imaging settings. The TomoTherapy automatic registration system accurately detects induced rotations, and the method presented here for evaluation of the roll correction feature is easily implemented by any clinic with a TomoTherapy Hi·Art unit. This method is sensitive to well within half a degree and demonstrates that the TomoTherapy Hi·Art roll correction feature accurately corrects for induced rotational misalignments to within this level of uncertainty. PACS numbers: 87.53.Jw, 87.53.Kn, 87.55.Qr, 87.57.nj |
format | Online Article Text |
id | pubmed-5690141 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-56901412018-04-02 Technical evaluation of TomoTherapy automatic roll correction Laub, Steve Snyder, Michael Burmeister, Jay J Appl Clin Med Phys Radiation Oncology Physics The TomoTherapy Hi·Art System allows the application of rotational corrections as a part of the pretreatment image guidance process. This study outlines a custom method to perform an end‐to‐end evaluation of the TomoTherapy Hi·Art roll correction feature. A roll‐sensitive plan was designed and delivered to a cylindrical solid water phantom to test the accuracy of roll corrections, as well as the ability of the automatic registration feature to detect induced roll. Cylindrical target structures containing coaxial inner avoidance structures were placed adjacent to the plane bisecting the phantom and 7 cm laterally off central axis. The phantom was positioned at isocenter with the target‐plane parallel to the couch surface. Varying degrees of phantom roll were induced and dose to the targets and inner avoidance structures was measured using Kodak EDR2 films placed in the target‐plane. Normalized point doses were compared with baseline (no roll) data to determine the sensitivity of the test and the effectiveness of the roll correction feature. Gamma analysis comparing baseline, roll‐corrected, and uncorrected films was performed using film analysis software. MVCT images were acquired prior to plan delivery. Measured roll was compared with induced roll to evaluate the automatic registration feature's ability to detect rotational misalignment. Rotations beyond 0.3° result in statistically significant deviation from baseline point measurements. Gamma pass rates begin to drop below 90% at approximately 0.5° induced rotation at [Formula: see text] and between 0.2° and 0.3° for 2%/2 mm. With roll correction applied, point dose measurements for all rotations are indistinguishable from baseline, and gamma pass rates exceed 96% when using 3% and 3 mm as evaluation criteria. Measured roll via the automatic registration algorithm agrees with induced rotation to within the test sensitivity for nearly all imaging settings. The TomoTherapy automatic registration system accurately detects induced rotations, and the method presented here for evaluation of the roll correction feature is easily implemented by any clinic with a TomoTherapy Hi·Art unit. This method is sensitive to well within half a degree and demonstrates that the TomoTherapy Hi·Art roll correction feature accurately corrects for induced rotational misalignments to within this level of uncertainty. PACS numbers: 87.53.Jw, 87.53.Kn, 87.55.Qr, 87.57.nj John Wiley and Sons Inc. 2015-05-08 /pmc/articles/PMC5690141/ /pubmed/26103471 http://dx.doi.org/10.1120/jacmp.v16i3.4836 Text en © 2015 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 Laub, Steve Snyder, Michael Burmeister, Jay Technical evaluation of TomoTherapy automatic roll correction |
title | Technical evaluation of TomoTherapy automatic roll correction |
title_full | Technical evaluation of TomoTherapy automatic roll correction |
title_fullStr | Technical evaluation of TomoTherapy automatic roll correction |
title_full_unstemmed | Technical evaluation of TomoTherapy automatic roll correction |
title_short | Technical evaluation of TomoTherapy automatic roll correction |
title_sort | technical evaluation of tomotherapy automatic roll correction |
topic | Radiation Oncology Physics |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5690141/ https://www.ncbi.nlm.nih.gov/pubmed/26103471 http://dx.doi.org/10.1120/jacmp.v16i3.4836 |
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