Cargando…

Comparison of Safety Margin Generation Concepts in Image Guided Radiotherapy to Account for Daily Head and Neck Pose Variations

PURPOSE: Intensity modulated radiation therapy (IMRT) of head and neck tumors allows a precise conformation of the high-dose region to clinical target volumes (CTVs) while respecting dose limits to organs a risk (OARs). Accurate patient setup reduces translational and rotational deviations between t...

Descripción completa

Detalles Bibliográficos
Autores principales: Stoll, Markus, Stoiber, Eva Maria, Grimm, Sarah, Debus, Jürgen, Bendl, Rolf, Giske, Kristina
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5199113/
https://www.ncbi.nlm.nih.gov/pubmed/28033416
http://dx.doi.org/10.1371/journal.pone.0168916
_version_ 1782488950207676416
author Stoll, Markus
Stoiber, Eva Maria
Grimm, Sarah
Debus, Jürgen
Bendl, Rolf
Giske, Kristina
author_facet Stoll, Markus
Stoiber, Eva Maria
Grimm, Sarah
Debus, Jürgen
Bendl, Rolf
Giske, Kristina
author_sort Stoll, Markus
collection PubMed
description PURPOSE: Intensity modulated radiation therapy (IMRT) of head and neck tumors allows a precise conformation of the high-dose region to clinical target volumes (CTVs) while respecting dose limits to organs a risk (OARs). Accurate patient setup reduces translational and rotational deviations between therapy planning and therapy delivery days. However, uncertainties in the shape of the CTV and OARs due to e.g. small pose variations in the highly deformable anatomy of the head and neck region can still compromise the dose conformation. Routinely applied safety margins around the CTV cause higher dose deposition in adjacent healthy tissue and should be kept as small as possible. MATERIALS AND METHODS: In this work we evaluate and compare three approaches for margin generation 1) a clinically used approach with a constant isotropic 3 mm margin, 2) a previously proposed approach adopting a spatial model of the patient and 3) a newly developed approach adopting a biomechanical model of the patient. All approaches are retrospectively evaluated using a large patient cohort of over 500 fraction control CT images with heterogeneous pose changes. Automatic methods for finding landmark positions in the control CT images are combined with a patient specific biomechanical finite element model to evaluate the CTV deformation. RESULTS: The applied methods for deformation modeling show that the pose changes cause deformations in the target region with a mean motion magnitude of 1.80 mm. We found that the CTV size can be reduced by both variable margin approaches by 15.6% and 13.3% respectively, while maintaining the CTV coverage. With approach 3 an increase of target coverage was obtained. CONCLUSION: Variable margins increase target coverage, reduce risk to OARs and improve healthy tissue sparing at the same time.
format Online
Article
Text
id pubmed-5199113
institution National Center for Biotechnology Information
language English
publishDate 2016
publisher Public Library of Science
record_format MEDLINE/PubMed
spelling pubmed-51991132017-01-19 Comparison of Safety Margin Generation Concepts in Image Guided Radiotherapy to Account for Daily Head and Neck Pose Variations Stoll, Markus Stoiber, Eva Maria Grimm, Sarah Debus, Jürgen Bendl, Rolf Giske, Kristina PLoS One Research Article PURPOSE: Intensity modulated radiation therapy (IMRT) of head and neck tumors allows a precise conformation of the high-dose region to clinical target volumes (CTVs) while respecting dose limits to organs a risk (OARs). Accurate patient setup reduces translational and rotational deviations between therapy planning and therapy delivery days. However, uncertainties in the shape of the CTV and OARs due to e.g. small pose variations in the highly deformable anatomy of the head and neck region can still compromise the dose conformation. Routinely applied safety margins around the CTV cause higher dose deposition in adjacent healthy tissue and should be kept as small as possible. MATERIALS AND METHODS: In this work we evaluate and compare three approaches for margin generation 1) a clinically used approach with a constant isotropic 3 mm margin, 2) a previously proposed approach adopting a spatial model of the patient and 3) a newly developed approach adopting a biomechanical model of the patient. All approaches are retrospectively evaluated using a large patient cohort of over 500 fraction control CT images with heterogeneous pose changes. Automatic methods for finding landmark positions in the control CT images are combined with a patient specific biomechanical finite element model to evaluate the CTV deformation. RESULTS: The applied methods for deformation modeling show that the pose changes cause deformations in the target region with a mean motion magnitude of 1.80 mm. We found that the CTV size can be reduced by both variable margin approaches by 15.6% and 13.3% respectively, while maintaining the CTV coverage. With approach 3 an increase of target coverage was obtained. CONCLUSION: Variable margins increase target coverage, reduce risk to OARs and improve healthy tissue sparing at the same time. Public Library of Science 2016-12-29 /pmc/articles/PMC5199113/ /pubmed/28033416 http://dx.doi.org/10.1371/journal.pone.0168916 Text en © 2016 Stoll et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Stoll, Markus
Stoiber, Eva Maria
Grimm, Sarah
Debus, Jürgen
Bendl, Rolf
Giske, Kristina
Comparison of Safety Margin Generation Concepts in Image Guided Radiotherapy to Account for Daily Head and Neck Pose Variations
title Comparison of Safety Margin Generation Concepts in Image Guided Radiotherapy to Account for Daily Head and Neck Pose Variations
title_full Comparison of Safety Margin Generation Concepts in Image Guided Radiotherapy to Account for Daily Head and Neck Pose Variations
title_fullStr Comparison of Safety Margin Generation Concepts in Image Guided Radiotherapy to Account for Daily Head and Neck Pose Variations
title_full_unstemmed Comparison of Safety Margin Generation Concepts in Image Guided Radiotherapy to Account for Daily Head and Neck Pose Variations
title_short Comparison of Safety Margin Generation Concepts in Image Guided Radiotherapy to Account for Daily Head and Neck Pose Variations
title_sort comparison of safety margin generation concepts in image guided radiotherapy to account for daily head and neck pose variations
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5199113/
https://www.ncbi.nlm.nih.gov/pubmed/28033416
http://dx.doi.org/10.1371/journal.pone.0168916
work_keys_str_mv AT stollmarkus comparisonofsafetymargingenerationconceptsinimageguidedradiotherapytoaccountfordailyheadandneckposevariations
AT stoiberevamaria comparisonofsafetymargingenerationconceptsinimageguidedradiotherapytoaccountfordailyheadandneckposevariations
AT grimmsarah comparisonofsafetymargingenerationconceptsinimageguidedradiotherapytoaccountfordailyheadandneckposevariations
AT debusjurgen comparisonofsafetymargingenerationconceptsinimageguidedradiotherapytoaccountfordailyheadandneckposevariations
AT bendlrolf comparisonofsafetymargingenerationconceptsinimageguidedradiotherapytoaccountfordailyheadandneckposevariations
AT giskekristina comparisonofsafetymargingenerationconceptsinimageguidedradiotherapytoaccountfordailyheadandneckposevariations