Dosimetric impact of Acuros XB deterministic radiation transport algorithm for heterogeneous dose calculation in lung cancer
Dosimetric impact of Acuros XB deterministic radiation transport algorithm for heterogeneous dose calculation in lung cancer
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DOI：
10.1118/1.4802216
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发表时间：
2013-05-01
期刊：
影响因子：
3.8
通讯作者：
Mourtada, Firas
中科院分区：
文献类型：
--
作者：
Han, Tao;Followill, David;Mourtada, Firas
目的：新的确定性辐射输运算法，Acuros XB（AXB），已显示出巨大的潜力，准确的非均匀剂量计算。然而，AXB和其他目前使用的算法之间的临床影响仍然需要阐明这些算法之间的转换。本研究旨在探讨AXB对肺癌调强放射治疗（IMRT）和调容弧治疗（VMAT）的非均匀剂量计算的影响。在Eclipse 11.0治疗计划系统中为体模创建IMRT和VMAT计划。使用Varian Clinac iX直线加速器将每个计划输送至体模三次，以确保再现性。将热释光剂量计（TLD）和Gafchromic EBT 2薄膜放置在体模内，以测量输送剂量。将测量值与AXB 11.0.21和各向异性分析算法（AAA）11.0.21的剂量计算值进行比较。研究了AXB的两种剂量报告模式，即介质中的介质剂量（D-m，D-m）和介质中的水剂量（D-w，D-m）。使用点剂量、剂量曲线和伽马分析来量化AXB和AAA的测量和计算之间的一致性。AAA和AXB的计算时间也evaluated.Results：对于RPC肺体模，AAA和AXB剂量预测被发现在良好的协议，IMRT和VMAT计划的X射线和电影测量。对AXB剂量（D-m、D-m和D-w、D-m）的预测值在0.4%-4.4%范围内;对AAA剂量的预测值在2.5%-6.4%范围内。对于胶片比较，AAA、AXB_D-m、D-m和AXB_D-w、D-m的伽马指数（+/- 3%/3 mm标准）分别为94%、97%和98%。AXB和AAA之间的剂量-体积直方图平均剂量差异在计划靶体积、肺、心脏中在2%以内，在脊髓中在5%以内。然而，AXB和AAA之间的差异高达8%，发现在肺/软组织界面区域的个人IMRT领域。在IMRT计划中，AAA比AXB快5-6倍，而在VMAT计划中，AXB比AAA快4-5倍。AXB和AAA之间的差异一般很小，除了在异质界面区域。AXB D-w、D-m和D-m、D-m计算在软组织和肺区域内相似。AXB可以通过提高准确性和减少计算时间来有益于肺VMAT计划。(c)2013年美国医学物理学家协会。
Purpose: The novel deterministic radiation transport algorithm, Acuros XB (AXB), has shown great potential for accurate heterogeneous dose calculation. However, the clinical impact between AXB and other currently used algorithms still needs to be elucidated for translation between these algorithms. The purpose of this study was to investigate the impact of AXB for heterogeneous dose calculation in lung cancer for intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT).Methods: The thorax phantom from the Radiological Physics Center (RPC) was used for this study. IMRT and VMAT plans were created for the phantom in the Eclipse 11.0 treatment planning system. Each plan was delivered to the phantom three times using a Varian Clinac iX linear accelerator to ensure reproducibility. Thermoluminescent dosimeters (TLDs) and Gafchromic EBT2 film were placed inside the phantom to measure delivered doses. The measurements were compared with dose calculations from AXB 11.0.21 and the anisotropic analytical algorithm (AAA) 11.0.21. Two dose reporting modes of AXB, dose-to-medium in medium (D-m,D-m) and dose-to-water in medium (D-w,D-m), were studied. Point doses, dose profiles, and gamma analysis were used to quantify the agreement between measurements and calculations from both AXB and AAA. The computation times for AAA and AXB were also evaluated.Results: For the RPC lung phantom, AAA and AXB dose predictions were found in good agreement to TLD and film measurements for both IMRT and VMAT plans. TLD dose predictions were within 0.4%-4.4% to AXB doses (both D-m,D-m and D-w,D-m); and within 2.5%-6.4% to AAA doses, respectively. For the film comparisons, the gamma indexes (+/- 3%/3 mm criteria) were 94%, 97%, and 98% for AAA, AXB_D-m,D-m, and AXB_D-w,D-m, respectively. The differences between AXB and AAA in dose-volume histogram mean doses were within 2% in the planning target volume, lung, heart, and within 5% in the spinal cord. However, differences up to 8% between AXB and AAA were found at lung/soft tissue interface regions for individual IMRT fields. AAA was found to be 5-6 times faster than AXB for IMRT, while AXB was 4-5 times faster than AAA for VMAT plan.Conclusions: AXB is satisfactorily accurate for the dose calculation in lung cancer for both IMRT and VMAT plans. The differences between AXB and AAA are generally small except in heterogeneous interface regions. AXB D-w,D-m and D-m,D-m calculations are similar inside the soft tissue and lung regions. AXB can benefit lung VMAT plans by both improving accuracy and reducing computation time. (c) 2013 American Association of Physicists in Medicine.