Beam's-eye-view dosimetrics (BEVD) guided rotational station parameter optimized radiation therapy (SPORT) planning based on reweighted total-variation minimization
Beam's-eye-view dosimetrics (BEVD) guided rotational station parameter optimized radiation therapy (SPORT) planning based on reweighted total-variation minimization
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DOI：
10.1088/0031-9155/60/5/n71
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发表时间：
2015-03-07
影响因子：
3.5
通讯作者：
Xing, Lei
中科院分区：
文献类型：
--
作者：
Kim, Hojin;Li, Ruijiang;Xing, Lei
传统的VMAT优化孔径形状和权重在均匀采样站，这是一个控制点的概念的概括。最近，旋转站参数优化放射治疗（SPORT）已被提出来提高计划质量，通过插入光束的区域，需要额外的强度调制，从而制定非均匀的光束采样。本文提出了一种新的旋转运动规划策略，该策略基于重新加权的总变差（TV）最小化（min.），使用射束视野剂量学（BEVD）引导的射束选择。基于凸规划的重新加权TV最小值确保了简化的注量图，这便于在每个站选择单孔径进行单弧输送。对于旋转弧治疗计划和非均匀射束角度设置，需要通过描述注量图相似性的附加惩罚项和通过确定适当的角度加权因子来修改数学模型。所提出的算法与额外的惩罚项是能够实现更有效的和可交付的计划适应于传统的VMAT和SPORT计划方案，通过减少剂量输送时间约5至10秒，在三个临床病例（前列腺和两个头颈部（HN）的情况下，一个单一的和多个目标）。BEVD引导波束选择提供了有效且简单的计算方法，以在SPORT规划中选择用于更密集、非均匀角度采样的角度。我们的BEVD引导的SPORT治疗方案改善了两例HN病例中前列腺和脑干、腮腺和口腔中股骨头的剂量节省，这些器官的平均剂量减少范围为0.5至2.5戈伊。此外，相对于传统的单弧VMAT计划，在前列腺和两个HN病例中，它将评估与目标的剂量符合性的符合性数从0.84、0.75和0.74增加到0.86、0.79和0.80，同时保持输送效率。
Conventional VMAT optimizes aperture shapes and weights at uniformly sampled stations, which is a generalization of the concept of a control point. Recently, rotational station parameter optimized radiation therapy (SPORT) has been proposed to improve the plan quality by inserting beams to the regions that demand additional intensity modulations, thus formulating non-uniform beam sampling. This work presents a new rotational SPORT planning strategy based on reweighted total-variation (TV) minimization (min.), using beam's-eye-view dosimetrics (BEVD) guided beam selection. The convex programming based reweighted TV min. assures the simplified fluence-map, which facilitates single-aperture selection at each station for single-arc delivery. For the rotational arc treatment planning and non-uniform beam angle setting, the mathematical model needs to be modified by additional penalty term describing the fluence-map similarity and by determination of appropriate angular weighting factors. The proposed algorithm with additional penalty term is capable of achieving more efficient and deliverable plans adaptive to the conventional VMAT and SPORT planning schemes by reducing the dose delivery time about 5 to 10 s in three clinical cases (one prostate and two head-and-neck (HN) cases with a single and multiple targets). The BEVD guided beam selection provides effective and yet easy calculating methodology to select angles for denser, non-uniform angular sampling in SPORT planning. Our BEVD guided SPORT treatment schemes improve the dose sparing to femoral heads in the prostate and brainstem, parotid glands and oral cavity in the two HN cases, where the mean dose reduction of those organs ranges from 0.5 to 2.5 Gy. Also, it increases the conformation number assessing the dose conformity to the target from 0.84, 0.75 and 0.74 to 0.86, 0.79 and 0.80 in the prostate and two HN cases, while preserving the delivery efficiency, relative to conventional single-arc VMAT plans.