1. An online adaptive plan library approach for intensity modulated proton therapy for head and neck cancer
- Author
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Michelle Oud, Sebastiaan Breedveld, Marta Giżyńska, Michiel Kroesen, Stefan Hutschemaekers, Steven Habraken, Steven Petit, Zoltán Perkó, Ben Heijmen, Mischa Hoogeman, and Radiotherapy
- Subjects
Organs at Risk ,Radiotherapy Planning, Computer-Assisted ,Radiotherapy Dosage ,Hematology ,Xerostomia ,Proton therapy ,Daily adaptive radiotherapy ,Inter-fraction motion ,Oncology ,SDG 3 - Good Health and Well-being ,Head and Neck Neoplasms ,Plan library ,Humans ,Intensity modulated proton therapy ,Radiology, Nuclear Medicine and imaging ,Radiotherapy, Intensity-Modulated ,Deglutition Disorders ,Head and neck cancer - Abstract
Background and purpose: In intensity modulated proton therapy (IMPT), the impact of setup errors and anatomical changes is commonly mitigated by robust optimization with population-based setup robustness (SR) settings and offline replanning. In this study we propose and evaluate an alternative approach based on daily plan selection from patient-specific pre-treatment established plan libraries (PLs). Clinical implementation of the PL strategy would be rather straightforward compared to daily online re-planning. Materials and methods: For 15 head-and-neck cancer patients, the planning CT was used to generate a PL with 5 plans, robustly optimized for increasing SR: 0, 1, 2, 3, 5 mm, and 3% range robustness. Repeat CTs (rCTs) and realistic setup and range uncertainty distributions were used for simulation of treatment courses for the PL approach, treatments with fixed SR (fSR3) and a trigger-based offline adaptive schedule for 3 mm SR (fSR3OfA). Daily plan selection in the PL approach was based only on recomputed dose to the CTV on the rCT. Results: Compared to using fSR3 and fSR3OfA, the risk of xerostomia grade ≥ II & III and dysphagia ≥ grade III were significantly reduced with the PL. For 6/15 patients the risk of xerostomia and/or dysphagia ≥ grade II could be reduced by > 2% by using PL. For the other patients, adherence to target coverage constraints was often improved. fSR3OfA resulted in significantly improved coverage compared to PL for selected patients. Conclusion: The proposed PL approach resulted in overall reduced NTCPs compared to fSR3 and fSR3OfA at limited cost in target coverage.
- Published
- 2022