Automated treatment planning for a dedicated multi-source intracranial radiosurgery treatment unit using projected gradient and grassfire algorithms
Automated treatment planning for a dedicated multi-source intracranial radiosurgery treatment unit using projected gradient and grassfire algorithms
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DOI：
10.1118/1.4709603
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发表时间：
2012-06-01
期刊：
影响因子：
3.8
通讯作者：
Ruschin, Mark
中科院分区：
文献类型：
--
作者：
Ghobadi, Kimia;Ghaffari, Hamid R.;Ruschin, Mark
目的：这项工作的目的是开发一个框架的放射外科治疗计划的逆问题的伽玛刀（R）Perfectum（TM）（PFX）颅内targets.Methods：在本研究中采取的方法包括两个部分。首先，一个混合的草火和球包装算法是用来获得拍摄位置（等中心）的基础上的几何形状的目标进行治疗。对于选定的等中心点，扇区持续时间优化（SDO）模型用于优化来自每个单独源库的每个准直器尺寸的辐射输送持续时间。SDO模型使用投影梯度算法求解。这种方法已被回顾性测试7手动计划的临床病例（包括11个病变），包括听神经瘤和脑metabolis.Results：在符合性和器官的风险（OAR）sparing方面，与逆规划方法实现的计划的质量，平均而言，改善相比，手动生成的计划。对于经典和Paddick定义，反向和正向计划之间的符合性指数的平均差异分别为-0.12（范围：-0.27至+0.03）和+0.08（范围：0.00-0.17），有利于反向计划。正向和反向计划之间接受处方剂量（V-100）的体积平均差异为0.2%（范围：-2.4%至+2.0%）。在针对等效覆盖率的计划重正化之后（即，V-100），正向和反向计划之间脑干1 mm（3）的剂量平均差异为-0.24戈伊（范围：-2.40至+2.02戈伊），有利于反向计划。射束开启时间随等中心点的数量而变化，但对于最佳计划，平均比手动计划长33分钟（范围：-17至+91 min）。在算法性能方面，所有显示计划的等中心点选择均在3 s内完成，而SDO平均在215 min内完成。结论：使用几何等中心选择和数学建模和优化技术可以执行PFX反向计划。获得的治疗计划均达到或超过临床指南，同时显示出高度的一致性。(C)2012年美国医学物理学家协会。[http：//dx.doi.org/10.1118/1.4709603]
Purpose: The purpose of this work is to develop a framework to the inverse problem for radiosurgery treatment planning on the Gamma Knife (R) Perfexion (TM) (PFX) for intracranial targets.Methods: The approach taken in the present study consists of two parts. First, a hybrid grassfire and sphere-packing algorithm is used to obtain shot positions (isocenters) based on the geometry of the target to be treated. For the selected isocenters, a sector duration optimization (SDO) model is used to optimize the duration of radiation delivery from each collimator size from each individual source bank. The SDO model is solved using a projected gradient algorithm. This approach has been retrospectively tested on seven manually planned clinical cases (comprising 11 lesions) including acoustic neuromas and brain metastases.Results: In terms of conformity and organ-at-risk (OAR) sparing, the quality of plans achieved with the inverse planning approach were, on average, improved compared to the manually generated plans. The mean difference in conformity index between inverse and forward plans was -0.12 (range: -0.27 to +0.03) and +0.08 (range: 0.00-0.17) for classic and Paddick definitions, respectively, favoring the inverse plans. The mean difference in volume receiving the prescribed dose (V-100) between forward and inverse plans was 0.2% (range: -2.4% to +2.0%). After plan renormalization for equivalent coverage (i.e., V-100), the mean difference in dose to 1 mm(3) of brainstem between forward and inverse plans was -0.24 Gy (range: -2.40 to +2.02 Gy) favoring the inverse plans. Beam-on time varied with the number of isocenters but for the most optimal plans was on average 33 min longer than manual plans (range: -17 to +91 min) when normalized to a calibration dose rate of 3.5 Gy/min. In terms of algorithm performance, the isocenter selection for all the presented plans was performed in less than 3 s, while the SDO was performed in an average of 215 min.Conclusions: PFX inverse planning can be performed using geometric isocenter selection and mathematical modeling and optimization techniques. The obtained treatment plans all meet or exceed clinical guidelines while displaying high conformity. (C) 2012 American Association of Physicists in Medicine.[http://dx.doi.org/10.1118/1.4709603]