Shinde Nimita, Zhu Yanan, Wang Wei, Li Wangyao, Lin Yuting, Gan Gregory N, Lominska Christopher, Rotondo Ronny, Chen Ronald C, Gao Hao
Department of Radiation Oncology, University of Kansas Medical Center, USA.
ArXiv. 2024 Nov 26:arXiv:2411.17578v1.
Proton spot-scanning arc therapy (ARC) is an emerging modality that can improve the high-dose conformity to targets compared with standard intensity-modulated proton therapy (IMPT). However, the efficient treatment delivery of ARC is challenging due to the required frequent energy changes during the continuous gantry rotation. This work proposes a novel method that delivers a multiple IMPT (multi-IMPT) plan that is equivalent to ARC in terms of biologically effective dose (BED).
The proposed multi-IMPT method utilizes a different subset of limited number of beam angles in each fraction for dose delivery. Due to the different dose delivered to organs at risk (OAR) in each fraction, we optimize biologically effective dose (BED) for OAR and the physical dose delivered for target in each fraction. The BED-based multi-IMPT inverse optimization problem is solved via the iterative convex relaxation method and the alternating direction method of multipliers. The effectiveness of the proposed multi-IMPT method is evaluated in terms of dose objectives in comparison with ARC.
Multi-IMPT provided similar plan quality with ARC. For example, multi-IMPT provided better OAR sparing and slightly better target dose coverage for the prostate case; similar dose distribution for the lung case; slightly worse dose coverage for the brain case; better dose coverage but slightly higher BED in OAR for the head-and-neck case.
We have proposed a multi-IMPT approach to deliver ARC-equivalent plan quality.
质子点扫描弧形治疗（ARC）是一种新兴的治疗方式，与标准调强质子治疗（IMPT）相比，它能提高对靶区的高剂量适形度。然而，由于在连续机架旋转过程中需要频繁改变能量，ARC的高效治疗实施具有挑战性。本研究提出一种新方法，即提供一种在生物等效剂量（BED）方面与ARC等效的多重IMPT（multi-IMPT）计划。
所提出的multi-IMPT方法在每个分次中利用有限数量射束角度的不同子集进行剂量输送。由于每个分次中输送到危及器官（OAR）的剂量不同，我们针对每个分次中的OAR优化生物等效剂量（BED）以及为靶区输送的物理剂量。基于BED的multi-IMPT逆向优化问题通过迭代凸松弛法和乘子交替方向法求解。与ARC相比，根据剂量目标评估所提出的multi-IMPT方法的有效性。
multi-IMPT与ARC具有相似的计划质量。例如，对于前列腺病例，multi-IMPT对OAR的保护更好且靶区剂量覆盖略优；对于肺部病例，剂量分布相似；对于脑部病例，剂量覆盖略差；对于头颈病例，剂量覆盖更好但OAR中的BED略高。
我们提出了一种multi-IMPT方法来提供与ARC等效的计划质量。
