Comparison of Safety Margin Generation Concepts in Image Guided Radiotherapy to Account for Daily Head and Neck Pose Variations
| Autor: | Markus Stoll, Jürgen Debus, Kristina Giske, Sarah Grimm, Rolf Bendl, Eva M. Stoiber |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Organs at Risk
medicine.medical_treatment Planning target volume Cancer Treatment lcsh:Medicine Safety margin Image guided radiotherapy Nervous System 030218 nuclear medicine & medical imaging Diagnostic Radiology Cohort Studies 0302 clinical medicine Margin (machine learning) Medicine and Health Sciences Head and neck lcsh:Science Tomography Multidisciplinary Radiology and Imaging Physics Applied Mathematics Uncertainty Classical Mechanics Deformation Biomechanical Phenomena Spinal Cord Oncology Head and Neck Neoplasms 030220 oncology & carcinogenesis Physical Sciences Radiology Anatomy Safety Research Article Clinical Oncology medicine.medical_specialty Imaging Techniques Finite Element Analysis Radiation Therapy Neuroimaging Research and Analysis Methods Models Biological Patient Positioning 03 medical and health sciences Diagnostic Medicine medicine Humans Medical physics Retrospective Studies Damage Mechanics business.industry lcsh:R Biology and Life Sciences Intensity-modulated radiation therapy Computed Axial Tomography Radiation therapy Neuroanatomy lcsh:Q Radiotherapy Intensity-Modulated Clinical Medicine business Tomography X-Ray Computed Head Neck Mathematics Neuroscience Radiotherapy Image-Guided |
| Zdroj: | PLoS ONE, Vol 11, Iss 12, p e0168916 (2016) PLoS ONE |
| ISSN: | 1932-6203 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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