Comparative analysis of thermoplastic masks versus vacuum cushions in stereotactic body radiotherapy.
Comparative analysis of thermoplastic masks versus vacuum cushions in stereotactic body radiotherapy.
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DOI：
10.1186/s13014-015-0484-7
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发表时间：
2015-08-20
期刊：
影响因子：
--
通讯作者：
Guedea F
中科院分区：
文献类型：
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作者：
Navarro-Martin A;Cacicedo J;Leaman O;Sancho I;García E;Navarro V;Guedea F
比较热塑面罩（TMP）和真空垫系统（VCA），以评估在接受立体定向放射治疗（SBRT）治疗的少转移性肺癌患者中分次间设置准确性的差异。其次，调查放射治疗技术人员对两种系统的满意度。对2008年至2012年在我们机构接受肺SBRT治疗的患者进行的回顾性研究。进行了73次固定治疗（n = 40; TMP = 33）。共分析了246个锥束。纳入了预期寿命≥6个月且体能状态> 1的不适合手术的患者。在每次治疗前通过锥形束计算机断层扫描（CBCT）验证靶病变位置，在每次治疗前通过CBCT模拟评估位移。在垂直、纵向和侧-横向方向上前瞻性记录治疗床移位，以获得内核坐标（3D表示）。技术人员进行了调查，以评估他们的满意度与索引，定位和学习曲线的两个系统。在每个治疗计划和每个疗程中，获得所有患者的设置位移。为了评估固定系统之间的差异，进行了t检验（Welch）。TMP和VC系统的平均位移分别如下：第一阶段，0.64 cm vs 1.05 cm（p = 0.0002）;第二阶段，0.49 cm vs 1.02 cm（p < 0.0001）;第三阶段，0.56 cm vs 0.97 cm（p = 0.0011）。在所有三个治疗阶段中，TMP导致的变化显著小于TBI。技术专家对TMP的学习曲线、设置和定位的评价高于TMP。由于肺SBRT中的高剂量和陡梯度，准确和可重复的分次间设置至关重要。我们发现，热塑性口罩提供了更好的再现性与显着更少的interfractional设置位移比真空垫。此外，放射治疗技术人员对TMP系统的评价更高。综上所述，这两个发现表明TMP可能优于顺铂。然而，需要更多的研究来确定分次间和分次内误差，以确定用于肺SBRT的最佳固定系统。
To compare thermoplastic masks (TMP) and vacuum cushion system (VCS) to assess differences in interfraction set up accuracy in patients treated with stereotactic radiotherapy (SBRT) for oligometastatic lung cancer. Secondarily, to survey radiotherapy technologists to assess their satisfaction with the two systems. Retrospective study of patients treated with lung SBRT between 2008 to 2012 at our institution. Immobilization was performed for 73 treatment sessions (VCS = 40; TMP = 33). A total of 246 cone-beams were analysed. Patients considered ineligible for surgery with a life expectancy ≥6 months and performance status > 1 were included. Target lesion location was verified by cone beam computed tomography (CBCT) prior to each session, with displacements assessed by CBCT simulation prior to each treatment session. Couch shifts were registered prospectively in vertical, longitudinal, and latero-lateral directions to obtain Kernel coordinates (3D representation). Technologists were surveyed to assess their satisfaction with indexing, positioning, and learning curve of the two systems. Setup displacements were obtained in all patients for each treatment plan and for each session. To assess differences between the immobilization systems, a t-test (Welch) was performed. Mean displacements for the TMP and VC systems, respectively, were as follows: session one, 0.64 cm vs 1.05 cm (p = 0.0002); session two, 0.49 cm vs 1.02 cm (p < 0.0001), and session three, 0.56 vs 0.97 cm (p = 0.0011). TMP resulted in significantly smaller shifts vs. VCS in all three treatment sessions. Technologists rated the learning curve, set up, and positioning more highly for TMP versus VCS. Due to the high doses and steep gradients in lung SBRT, accurate and reproducible inter-fraction set up is essential. We found that thermoplastic masks offers better reproducibility with significantly less interfractional set up displacement than vacuum cushions. Moreover, radiotherapy technologists rated the TMP system higher. Taken together, these two findings suggest that TMP may be preferable to VCS. However, more research is needed to determine both inter- and intrafraction error to identify the optimal immobilisation system for use in lung SBRT.