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Dosimetric impacts of applicator displacements and applicator reconstruction-uncertainties on 3D image-guided brachytherapy for cervical cancer
PURPOSE: To quantify the dosimetric impact of applicator displacements and applicator reconstruction-uncertainties through simulated planning studies of virtual applicator shifts. MATERIAL AND METHODS: Twenty randomly selected high-dose-rate (HDR) titanium tandem-and-ovoid (T&O) plans were retro...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Termedia Publishing House
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3899640/ https://www.ncbi.nlm.nih.gov/pubmed/24474977 http://dx.doi.org/10.5114/jcb.2013.39453 |
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author | Schindel, Joshua Zhang, Winson Bhatia, Sudershan K. Sun, Wenqing Kim, Yusung |
author_facet | Schindel, Joshua Zhang, Winson Bhatia, Sudershan K. Sun, Wenqing Kim, Yusung |
author_sort | Schindel, Joshua |
collection | PubMed |
description | PURPOSE: To quantify the dosimetric impact of applicator displacements and applicator reconstruction-uncertainties through simulated planning studies of virtual applicator shifts. MATERIAL AND METHODS: Twenty randomly selected high-dose-rate (HDR) titanium tandem-and-ovoid (T&O) plans were retrospectively studied. MRI-guided, conformal brachytherapy (MRIG-CBT) plans were retrospectively generated. To simulate T&O displacement, the whole T&O set was virtually shifted on treatment planning system in the cranial (+) and the caudal (–) direction after each dose calculation. Each shifted plan was compared to an unshifted plan. To simulate T&O reconstruction-uncertainties, each tandem and ovoid was separately shifted along its axis before performing the dose calculation. After the dose calculation, the calculated isodose lines and T&O were moved back to unshifted T&O position. Shifted and shifted-back plan were compared. RESULTS: Regarding the dosimetric impact of the simulated T&O displacements, rectal D(2cc) values were observed as being the most sensitive to change due to T&O displacement among all dosimetric metrics regardless of point A (p < 0.013) or MRIG-CBT plans (p < 0.0277). To avoid more than 10% change, ± 1.5 mm T&O displacements were accommodated for both point A and MRIG-CBT plans. The dosimetric impact of T&O displacements on sigmoid (p < 0.0005), bladder (p < 0.0001), HR-CTV (p < 0.0036), and point A (p < 0.0015) were significantly larger in the MRIG-CBT plans than point A plans. Regarding the dosimetric impact of T&O reconstruction-uncertainties, less than ± 3.0 mm reconstruction-uncertainties were also required in order to avoid more than 10% dosimetric change in either the point A or MRIG-CBT plans. CONCLUSIONS: The dosimetric impact of simulated T&O displacements was significantly larger in the MRIG-CBT plans than in the point A plans. Either ± 3 mm T&O displacement or a ± 4.5 mm T&O reconstruction-uncertainty could cause greater than 10% dosimetric change for both point A plans and MRIG-CBT plans. |
format | Online Article Text |
id | pubmed-3899640 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | Termedia Publishing House |
record_format | MEDLINE/PubMed |
spelling | pubmed-38996402014-01-28 Dosimetric impacts of applicator displacements and applicator reconstruction-uncertainties on 3D image-guided brachytherapy for cervical cancer Schindel, Joshua Zhang, Winson Bhatia, Sudershan K. Sun, Wenqing Kim, Yusung J Contemp Brachytherapy Original Paper PURPOSE: To quantify the dosimetric impact of applicator displacements and applicator reconstruction-uncertainties through simulated planning studies of virtual applicator shifts. MATERIAL AND METHODS: Twenty randomly selected high-dose-rate (HDR) titanium tandem-and-ovoid (T&O) plans were retrospectively studied. MRI-guided, conformal brachytherapy (MRIG-CBT) plans were retrospectively generated. To simulate T&O displacement, the whole T&O set was virtually shifted on treatment planning system in the cranial (+) and the caudal (–) direction after each dose calculation. Each shifted plan was compared to an unshifted plan. To simulate T&O reconstruction-uncertainties, each tandem and ovoid was separately shifted along its axis before performing the dose calculation. After the dose calculation, the calculated isodose lines and T&O were moved back to unshifted T&O position. Shifted and shifted-back plan were compared. RESULTS: Regarding the dosimetric impact of the simulated T&O displacements, rectal D(2cc) values were observed as being the most sensitive to change due to T&O displacement among all dosimetric metrics regardless of point A (p < 0.013) or MRIG-CBT plans (p < 0.0277). To avoid more than 10% change, ± 1.5 mm T&O displacements were accommodated for both point A and MRIG-CBT plans. The dosimetric impact of T&O displacements on sigmoid (p < 0.0005), bladder (p < 0.0001), HR-CTV (p < 0.0036), and point A (p < 0.0015) were significantly larger in the MRIG-CBT plans than point A plans. Regarding the dosimetric impact of T&O reconstruction-uncertainties, less than ± 3.0 mm reconstruction-uncertainties were also required in order to avoid more than 10% dosimetric change in either the point A or MRIG-CBT plans. CONCLUSIONS: The dosimetric impact of simulated T&O displacements was significantly larger in the MRIG-CBT plans than in the point A plans. Either ± 3 mm T&O displacement or a ± 4.5 mm T&O reconstruction-uncertainty could cause greater than 10% dosimetric change for both point A plans and MRIG-CBT plans. Termedia Publishing House 2013-12-18 2013-12 /pmc/articles/PMC3899640/ /pubmed/24474977 http://dx.doi.org/10.5114/jcb.2013.39453 Text en Copyright © 2013 Termedia http://creativecommons.org/licenses/by-nc-nd/3.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution-Noncommercial 3.0 Unported License, permitting all non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Original Paper Schindel, Joshua Zhang, Winson Bhatia, Sudershan K. Sun, Wenqing Kim, Yusung Dosimetric impacts of applicator displacements and applicator reconstruction-uncertainties on 3D image-guided brachytherapy for cervical cancer |
title | Dosimetric impacts of applicator displacements and applicator reconstruction-uncertainties on 3D image-guided brachytherapy for cervical cancer |
title_full | Dosimetric impacts of applicator displacements and applicator reconstruction-uncertainties on 3D image-guided brachytherapy for cervical cancer |
title_fullStr | Dosimetric impacts of applicator displacements and applicator reconstruction-uncertainties on 3D image-guided brachytherapy for cervical cancer |
title_full_unstemmed | Dosimetric impacts of applicator displacements and applicator reconstruction-uncertainties on 3D image-guided brachytherapy for cervical cancer |
title_short | Dosimetric impacts of applicator displacements and applicator reconstruction-uncertainties on 3D image-guided brachytherapy for cervical cancer |
title_sort | dosimetric impacts of applicator displacements and applicator reconstruction-uncertainties on 3d image-guided brachytherapy for cervical cancer |
topic | Original Paper |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3899640/ https://www.ncbi.nlm.nih.gov/pubmed/24474977 http://dx.doi.org/10.5114/jcb.2013.39453 |
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