Lattice position optimization for LATTICE therapy.
Lattice position optimization for LATTICE therapy.
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DOI：
10.1002/mp.16572
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发表时间：
2023-06
期刊：
影响因子：
3.8
通讯作者：
Weijie Zhang;Yuting Lin;Feng Wang;R. Badkul;Ronald C. Chen;Hao Gao
中科院分区：
文献类型：
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作者：
Weijie Zhang;Yuting Lin;Feng Wang;R. Badkul;Ronald C. Chen;Hao Gao
背景晶格放射治疗将高峰谷剂量比（PVDR）的3D异质剂量递送到肿瘤靶，其中峰值剂量在靶内的晶格顶点处，谷剂量用于靶的其余部分。尽管网格顶点位置可以影响靶内的PVDR和危及器官（OAR）的保留，但是它们被固定为常数，并且在当前临床实践中在治疗规划期间未被优化。目的提出一种新的LATTICE计划优化方法，可以在LATTICE治疗计划过程中优化点阵顶点位置，这是我们所知的第一个点阵位置优化研究。新的LATTICE治疗计划方法优化了晶格顶点位置以及其他计划变量（例如，光子注量或质子点权重），具有针对目标PVDR和OAR节省的优化目标。为了满足数学上的可微性，格点用S形函数近似。对于几何可行性，适当的几何约束施加到晶格顶点位置上。采用迭代凸松弛法（ICR）和交替方向乘子法（ADMM）求解晶格位置优化问题，采用拟牛顿法联合更新晶格顶点位置和光子/质子平面变量.结果在标准IMRT/IMPT的基础上，通过穷举搜索，在给定的离散位置上求解所有可能的组合，得到了基于计划目标的最佳网格顶点位置，并以此作为验证新方法的基础事实。结果表明，新方法确实提供了最小优化目标、最大目标PVDR和最佳OAR保留的最优格点位置。结论提出并验证了一种新的LATTICE治疗计划方法，该方法可以优化晶格顶点位置以及其他光子或质子计划变量，以改善目标PVDR和OAR保留。
BACKGROUND LATTICE radiation therapy delivers 3D heterogenous dose of high peak-to-valley dose ratio (PVDR) to the tumor target, with peak dose at lattice vertices inside the target and valley dose for the rest of the target. Although the lattice vertex positions can impact PVDR inside the target and sparing of organs-at-risk (OAR), they are fixed as constants and not optimized during treatment planning in current clinical practice. PURPOSE This work proposes a new LATTICE plan optimization method that can optimize lattice vertex positions during LATTICE treatment planning, which is the first lattice position optimization study to the best of our knowledge. METHODS The new LATTICE treatment planning method optimizes lattice vertex positions as well as other plan variables (e.g., photon fluences or proton spot weights), with optimization objectives for target PVDR and OAR sparing. To satisfy mathematical differentiability, the lattice vertices are approximated in sigmoid functions. For geometric feasibility, proper geometry constraints are enforced onto lattice vertex positions. The lattice position optimization problem is solved by iterative convex relaxation (ICR) method and alternating direction method of multipliers (ADMM), and lattice vertex positions and photon/proton plan variables are jointly updated via the Quasi-Newton method. RESULTS Both photon and proton LATTICE RT were considered, and the optimal lattice vertex positions in terms of plan objectives were found by solving all possible combinations on given discrete positions via exhaustive searching based on standard IMRT/IMPT, which served as the ground truth for validating the new LATTICE method. The results show that the new method indeed provided the optimal lattice vertex positions with the smallest optimization objective, the largest target PVDR, and the best OAR sparing. CONCLUSIONS A new LATTICE treatment planning method is proposed and validated that can optimize lattice vertex positions as well as other photon or proton plan variables for improving target PVDR and OAR sparing.