LETd Optimization Verification With an SOI Microdosimeter
Publication Name
International Journal of Radiation Oncology Biology Physics
Abstract
Purpose: A first of its kind experimental verification of dose-averaged linear energy transfer (LETd) optimized treatment plans for proton therapy has been carried out using a silicon-on-insulator microdosimeter at the Massachusetts General Hospital (MGH), Boston, USA. Methods and Materials: Three clinical treatment plans of a typical ependymoma structure set were designed using the standard clinical approach, the proposed protocol approach, and a one-field approach. The plans were then reoptimized to reduce the LETd-weighted dose in the brain stem. All six plans were delivered in a solid water phantom and the experimental yD‾ measured. Results: After LETd optimization, a reduction in yD‾ was found within the brain stem by an average of 12%, 19%, and 4% for the clinical, protocol, and one-field plans, respectively, while maintaining adequate coverage of the tumor structure. The experimental LETd-weighted doses were in agreement with the treatment planning system calculations and Monte Carlo simulations and reinforced the improvement of the optimization. Conclusions: This work demonstrates the first experimental verification of the clinical implementation of LETd optimization for patient treatment with proton therapy.
Open Access Status
This publication is not available as open access
Funding Number
2021/CDF1112
Funding Sponsor
National Health and Medical Research Council