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The price of robustness; impact of worst-case optimization on organ-at-risk dose and complication probability in intensity-modulated proton therapy for oropharyngeal cancer patients.
- Source :
-
Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology [Radiother Oncol] 2016 Jul; Vol. 120 (1), pp. 56-62. Date of Electronic Publication: 2016 May 10. - Publication Year :
- 2016
-
Abstract
- Purpose: To quantify the impact of the degree of robustness against setup errors and range errors on organ-at-risk (OAR) dose and normal tissue complication probabilities (NTCPs) in intensity-modulated proton therapy for oropharyngeal cancer patients.<br />Material and Methods: For 20 oropharyngeal cases (10 unilateral and 10 bilateral), robust treatment plans were generated using 'minimax' worst-case optimization. We varied the robustness against setup errors ('setup robustness') from 1 to 7mm and the robustness against range errors ('range robustness') from 1% to 7% (+1mm). We evaluated OAR doses and NTCP-values for xerostomia, dysphagia and larynx edema.<br />Results: Varying the degree of setup robustness was found to have a considerably larger impact than varying the range robustness. Increasing setup robustness from 1mm to 3, 5, and 7mm resulted in average NTCP-values to increase by 1.9, 4.4 and 7.5 percentage point, whereas they increased by only 0.4, 0.8 and 1.2 percentage point when increasing range robustness from 1% to 3%, 5% and 7%. The degree of setup robustness was observed to have a clinically significant impact in bilateral cases in particular.<br />Conclusions: For oropharyngeal cancer patients, minimizing setup errors should be given a higher priority than minimizing range errors.<br /> (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)
Details
- Language :
- English
- ISSN :
- 1879-0887
- Volume :
- 120
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology
- Publication Type :
- Academic Journal
- Accession number :
- 27178142
- Full Text :
- https://doi.org/10.1016/j.radonc.2016.04.038