Dose planning variations related to delineation variations in MRI-guided brachytherapy for locally advanced cervical cancer
Dose planning variations related to delineation variations in MRI-guided brachytherapy for locally advanced cervical cancer
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DOI：
10.1016/j.brachy.2020.01.002
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发表时间：
2020-03-01
期刊：
影响因子：
1.9
通讯作者：
Hellebust, Taran Paulsen
中科院分区：
文献类型：
--
作者：
Bell, Lauren;Holloway, Lois;Hellebust, Taran Paulsen
目的：研究宫颈癌腔内图像引导适应性近距离放射治疗中轮廓变化引起的处方剂量变化。确定剂量学结果与圈定不确定度指标之间的相关性。方法和材料：采用了一项关于轮廓不确定性的EMBRACE子研究的数据集，包括由10名经验丰富的观察者（靶体积和危险器官）描绘的6例宫颈癌患者的磁共振图像。生成了两个金标准轮廓，一个专家共识和同时的真值和性能水平估计。平面图被单独优化到所有的轮廓集（总共12个）。对金标准轮廓集应用方案，确定剂量体积直方图参数D-90、D-98和D-2cm(3)。评估了计划之间的可变性。剂量体积直方图参数和圈定不确定性指标使用Spearman的非参数秩相关进行关联。结果：在观察者、患者和用于分析的金标准轮廓线之间存在剂量学变异性。在CTVHR中观察到大约3 Gy D-90 EQD2（10）变异（SD），在危险器官中观察到1.2-3.6 Gy D-2cm(3) EQD2(3)。圈定的最大几何尺寸通常与剂量学变化有关。尽管黄金标准之间的相关性相似，但这些相关性的方向不同，这表明剂量学结果依赖于计划优化到的轮廓。结论：本研究强调了在宫颈癌近距离放疗中，观察者之间轮廓不确定性的剂量学差异。他重申了谨慎选择作为基准的黄金标准的重要性。(C) 2020美国近距离放射治疗学会。Elsevier Inc.出版。版权所有。
PURPOSE: To examine the variability in prescribed dose due to contouring variations in intracavitary image-guided adaptive brachytherapy for cervical cancer. To identify correlations between dosimetric outcomes and delineation uncertainty metrics.METHODS AND MATERIALS: A data set from an EMBRACE sub-study on contouring uncertainties was used, consisting of magnetic resonance images of six patients with cervical cancer delineated by 10 experienced observers (target volumes and organs at risk). Two gold standard contours were generated, an expert consensus and the simultaneous truth and performance level estimation. Plans were individually optimised to all of the contour sets (12 in total). Plans were applied to the gold standard contour sets, and dose volume histogram parameters including D-90, D-98 and D-2cm(3) were determined. The variability between plans was assessed. Dose volume histogram parameters and delineation uncertainty metrics were correlated using the Spearman's non-parametric rank correlation.RESULTS: There is a dosimetric variability between observers, patients and the gold standard contour used for analysis. Approximately 3 Gy D-90 EQD2(10) variability (SD) was observed for the CTVHR and 1.2-3.6 Gy D-2cm(3) EQD2(3) for the organs at risk. The maximum geometric dimensions of the delineations are most commonly correlated with dosimetry changes. Although the correlations are similar across gold standards, the direction of these correlations differs, indicating that the dosimetric outcomes are dependent on the contour that the plan is optimised to.CONCLUSION: This study highlights the dosimetric differences interobserver uncertainty in contouring can have for cervical cancer brachytherapy. The importance of carefully choosing a gold standard from which to benchmark is reiterated. (C) 2020 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.