Inverse planning for IMRT with nonuniform beam profiles using total-variation regularization (TVR)
Inverse planning for IMRT with nonuniform beam profiles using total-variation regularization (TVR)
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DOI：
10.1118/1.3521465
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发表时间：
2011-01-01
期刊：
影响因子：
3.8
通讯作者：
Xing, Lei
中科院分区：
文献类型：
--
作者：
Kim, Taeho;Zhu, Lei;Xing, Lei
目的：高剂量率、平坦化无滤光片(FFF)放射治疗具有显著缩短治疗时间和野外剂量的潜在优势。然而，当前的逆计划算法并不是针对具有非均匀入射轮廓的光束定制的，由此产生的调强放射治疗计划在交付方面往往效率低下。通过考虑入射光束轮廓的固有形状，提出了一种基于全变差正则化(TVR)的逆规划算法。作者在目标函数中引入了TVR项，鼓励在非均匀FFF流量域中分段恒定的通量。将所提出的算法应用于肺、前列腺和头颈部病例，并通过将所得到的计划与传统的基于束流的优化(BBO)得到的计划进行比较来评估其性能。结果：对于前列腺病例，作者的算法仅产生可接受的21个节段的剂量分布，而传统的BBO需要114个节段。对于肺部和头颈部病例，与BBO相比，该方法产生的靶区体积和危险器官的保留范围相似，但节段数明显减少。结论：基于TVR的非平坦束流域优化提供了一种最大限度地利用FFF场放射治疗的技术能力的有效途径。该技术可以产生有效的调强放射治疗计划，并在不显著恶化剂量分布的情况下提高剂量传递效率。(C)2011年美国医学物理学家协会。[DOI：10.1118/1.3521465]
Purpose: Radiation therapy with high dose rate and flattening filter-free (FFF) beams has the potential advantage of greatly reduced treatment time and out-of-field dose. Current inverse planning algorithms are, however, not customized for beams with nonuniform incident profiles and the resultant IMRT plans are often inefficient in delivery. The authors propose a total-variation regularization (TVR)-based formalism by taking the inherent shapes of incident beam profiles into account.Methods: A novel TVR-based inverse planning formalism is established for IMRT with nonuniform beam profiles. The authors introduce a TVR term into the objective function, which encourages piecewise constant fluence in the nonuniform FFF fluence domain. The proposed algorithm is applied to lung and prostate and head and neck cases and its performance is evaluated by comparing the resulting plans to those obtained using a conventional beamlet-based optimization (BBO).Results: For the prostate case, the authors' algorithm produces acceptable dose distributions with only 21 segments, while the conventional BBO requires 114 segments. For the lung case and the head and neck case, the proposed method generates similar coverage of target volume and sparing of the organs-at-risk as compared to BBO, but with a markedly reduced segment number.Conclusions: TVR-based optimization in nonflat beam domain provides an effective way to maximally leverage the technical capacity of radiation therapy with FFF fields. The technique can generate effective IMRT plans with improved dose delivery efficiency without significant deterioration of the dose distribution. (C) 2011 American Association of Physicists in Medicine. [DOI: 10.1118/1.3521465]