Research on robust optimization method of intensity-modulated proton therapy
10.3760/cma.j.cn113030-20200228-00078
- VernacularTitle:质子调强放疗计划的鲁棒性优化方法研究
- Author:
Rongcheng HAN
1
;
Yuehu PU
;
Haiyun KONG
;
Xiufang LI
;
Chao WU
Author Information
1. 中国科学院上海应用物理研究所 201800；中国科学院大学，北京 100049
- From:
Chinese Journal of Radiation Oncology
2020;29(10):888-893
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To propose a new robust optimization method, known as modified worst case method, was proposed, which can enable users to control the trade-off between nominal plan quality and plan robustness.Methods:In each iteration of the plan optimization process, the dose value of each voxel in nine scenarios, which corresponded to a nominal scenario and eight perturbed scenarios with range or set-up uncertainties, were calculated and the maximum of deviations of each scenario voxel dose from that of the nominal scenario was included as an additive robust optimization term in the objective function. A weighting factor p robust was used to this robust optimization term to balance the nominal plan quality and plan robustness. Results:The robust optimization methods were implemented and compared in an in-house developed robust optimization module. When p robust=0.8, compared with conventional optimization, the ΔD 95% of CTV was reduced from 9.8 Gy to 7.6 Gy. When p robust was reduced from 1 to 0, ΔD 95% was increased from 7.0 Gy to 9.8 Gy, whereas the D 95% and D max of CTV, and the D 5% and D max of organs at risk (OAR) in the nominal scenario were reduced. Conclusions:The proposed modified worst case method can effectively improve the robustness of the plan to the range and set-up uncertainties. Besides, the weighting factor p robust in this method can be adopted to control the trade-off between nominal plan quality and plan robustness.
