Reduced lung dose during radiotherapy for thoracic esophageal carcinoma: VMAT combined with active breathing control for moderate DIBH.
Reduced lung dose during radiotherapy for thoracic esophageal carcinoma: VMAT combined with active breathing control for moderate DIBH.
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DOI：
10.1186/1748-717x-8-291
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发表时间：
2013-12-20
期刊：
影响因子：
--
通讯作者：
Yin Y
中科院分区：
文献类型：
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作者：
Gong G;Wang R;Guo Y;Zhai D;Liu T;Lu J;Chen J;Liu C;Yin Y
放射性肺损伤是胸段食管癌放射治疗的重要并发症。因此，本研究的目标是通过应用容积调制弧形放射治疗（VMAT）结合主动呼吸控制（ABC）进行中度深吸气屏气（mDIBH）来研究胸部EC RT期间降低肺组织照射剂量的可行性和剂量学效应。随机选择15名胸部EC患者进行两个系列的计算机断层扫描（CT）模拟扫描，ABC用于实现mDIBH（代表峰值DIBH值的80%）与自由呼吸（FB）。在不同的CT图像上勾画大体肿瘤体积，并使用不同的边缘获得计划靶体积（PTV）。PTV-FB的调强放射治疗（IMRT）设计为7个野，VMAT包括两个整弧。对于PTV-DIBH，应用具有三个135°弧的VMAT，并且相应的计划分别命名为：IMRT-FB、VMAT-FB和VMAT-DIBH。比较了不同计划之间的剂量学差异。与FB相比，mDIBH的心脏体积减少19.85%，而肺总体积增加52.54%（p < 0.05）。VMAT-DIBH的平均适形性指数值和均匀性指数值（0.86，1.07）略差于IMRT-FB（0.90，1.05）和VMAT-FB（0.90，1.06）（p > 0.05）。此外，与IMRT-FB和VMAT-FB相比，VMAT-DIBH分别使平均总肺剂量降低了18.64%和17.84（p < 0.05）; IMRT-FB和VMAT-FB的V5、V10、V20和V30值分别降低了10.84%和10.65%（p > 0.05）、12.5%和20%（p < 0.05）、30.77%和33.33%（p < 0.05）、50.33%和49.15%（p < 0.05）。但VMAT-DIBH和VMAT-FB的心脏剂量-体积指数相似，均低于IMRT-FB，但无统计学意义（p > 0.05）。VMAT-DIBH的监测单位和治疗时间也最低（p < 0.05）。VMAT结合ABC实现mDIBH是胸部EC RT的可行方法。此外，该方法有可能在更短的治疗时间内有效降低肺部剂量，并具有更好的靶向准确性。
Lung radiation injury is a critical complication of radiotherapy (RT) for thoracic esophageal carcinoma (EC). Therefore, the goal of this study was to investigate the feasibility and dosimetric effects of reducing the lung tissue irradiation dose during RT for thoracic EC by applying volumetric modulated arc radiotherapy (VMAT) combined with active breathing control (ABC) for moderate deep inspiration breath-hold (mDIBH). Fifteen patients with thoracic EC were randomly selected to undergo two series of computed tomography (CT) simulation scans with ABC used to achieve mDIBH (representing 80% of peak DIBH value) versus free breathing (FB). Gross tumor volumes were contoured on different CT images, and planning target volumes (PTVs) were obtained using different margins. For PTV-FB, intensity-modulated radiotherapy (IMRT) was designed with seven fields, and VMAT included two whole arcs. For PTV-DIBH, VMAT with three 135° arcs was applied, and the corresponding plans were named: IMRT-FB, VMAT-FB, and VMAT-DIBH, respectively. Dosimetric differences between the different plans were compared. The heart volumes decreased by 19.85%, while total lung volume increased by 52.54% in mDIBH, compared to FB (p < 0.05). The mean conformality index values and homogeneity index values for VMAT-DIBH (0.86, 1.07) were slightly worse than those for IMRT-FB (0.90, 1.05) and VMAT-FB (0.90, 1.06) (p > 0.05). Furthermore, compared to IMRT-FB and VMAT-FB, VMAT-DIBH reduced the mean total lung dose by 18.64% and 17.84%, respectively (p < 0.05); moreover, the V5, V10, V20, and V30 values for IMRT-FB and VMAT-FB were reduced by 10.84% and 10.65% (p > 0.05), 12.5% and 20% (p < 0.05), 30.77% and 33.33% (p < 0.05), and 50.33% and 49.15% (p < 0.05), respectively. However, the heart dose-volume indices were similar between VMAT-DIBH and VMAT-FB which were lower than IMRT-FB without being statistically significant (p > 0.05). The monitor units and treatment time of VMAT-DIBH were also the lowest (p < 0.05). VMAT combined with ABC to achieve mDIBH is a feasible approach for RT of thoracic EC. Furthermore, this method has the potential to effectively reduce lung dose in a shorter treatment time and with better targeting accuracy.