Visualization of a variety of possible dosimetric outcomes in radiation therapy using dose-volume histogram bands
Visualization of a variety of possible dosimetric outcomes in radiation therapy using dose-volume histogram bands
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DOI：
10.1016/j.prro.2011.08.001
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发表时间：
2012-07-01
影响因子：
3.3
通讯作者：
Bortfeld, Thomas
中科院分区：
文献类型：
--
作者：
Trofimov, Alexei;Unkelbach, Jan;Bortfeld, Thomas
目的：剂量体积直方图（DVH）是评价临床治疗计划质量的最常用工具。然而，当存在输送不确定性时，DVH可能并不总是准确地描述实际输送给患者的剂量分布。我们提出了一种方法，DVH形式主义的基础上，可视化的变化，在预期的剂量测定结果的治疗plannes.Methods：对于颈椎脉络膜的情况下，我们比较了2强度调制质子治疗计划。仅根据剂量测定目标（即，所需靶区覆盖率、正常组织耐受性）优化治疗计划A。计划B采用已发表的概率优化方法创建，该方法考虑了患者设置和组织中质子范围的不确定性。针对标称输送场景以及代表标称设置偏差的场景和组织范围估计的系统误差，计算了两个计划的剂量分布和DVH。直方图fromvarious bodies被结合到cardiac DVH波段，以说明可能的偏差，从标称计划的预期幅度的设置和范围errors.Results：在标称的情况下，DVH从计划A显示优越的上级剂量覆盖范围内的目标，更高的剂量均匀性，并改善备用相邻的关键结构。然而，当针对不同的错误场景（例如，质子射程低估3 mm）重新计算计划A和B的剂量分布和DVH时，计划A的计划质量（由DVH反映）显著恶化，而计划B仅受到最小影响。在DVH-波段表示，计划A产生更宽的波段，反映其更高的脆弱性，交付错误，和剂量测定output.Conclusions的不确定性：结果表明，DVH的比较仅为标称方案不提供任何信息的剂量测定结果交付不确定性的相对敏感性。因此，这种比较可能是误导性的，并且可能导致选择较差的计划来递送给患者。如果提供了关于可能的剂量变异性的额外信息，例如，以DVH带的形式，则可以做出更明智的决定。(C)2012年美国放射肿瘤学会。爱思唯尔公司出版All rights reserved.
Purpose: Dose-volume histograms (DVH) are the most common tool used in the appraisal of the quality of a clinical treatment plan. However, when delivery uncertainties are present, the DVH may not always accurately describe the dose distribution actually delivered to the patient. We present a method, based on DVH formalism, to visualize the variability in the expected dosimetric outcome of a treatment plan.Methods: For a case of chordoma of the cervical spine, we compared 2 intensity modulated proton therapy plans. Treatment plan A was optimized based on dosimetric objectives alone (ie, desired target coverage, normal tissue tolerance). Plan B was created employing a published probabilistic optimization method that considered the uncertainties in patient setup and proton range in tissue. Dose distributions andDVHfor both planswere calculated for the nominal delivery scenario, aswell as for scenarios representing deviations from the nominal setup, and a systematic error in the estimate of range in tissue. The histograms fromvarious scenarioswere combined to createDVHbands to illustrate possible deviations from the nominal plan for the expected magnitude of setup and range errors.Results: In the nominal scenario, the DVH from plan A showed superior dose coverage, higher dose homogeneity within the target, and improved sparing of the adjacent critical structure. However, when the dose distributions and DVH from plans A and B were recalculated for different error scenarios (eg, proton range underestimation by 3 mm), the plan quality, reflected by DVH, deteriorated significantly for plan A, while plan B was only minimally affected. In the DVH-band representation, plan A produced wider bands, reflecting its higher vulnerability to delivery errors, and uncertainty in the dosimetric outcome.Conclusions: The results illustrate that comparison of DVH for the nominal scenario alone does not provide any information about the relative sensitivity of dosimetric outcome to delivery uncertainties. Thus, such comparison may be misleading and may result in the selection of an inferior plan for delivery to a patient. A better-informed decision can be made if additional information about possible dosimetric variability is presented; for example, in the form of DVH bands. (C) 2012 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.