Experimental validation of deterministic Acuros XB algorithm for IMRT and VMAT dose calculations with the Radiological Physics Center's head and neck phantom
Experimental validation of deterministic Acuros XB algorithm for IMRT and VMAT dose calculations with the Radiological Physics Center's head and neck phantom
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DOI：
10.1118/1.3692180
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发表时间：
2012-04-01
期刊：
影响因子：
3.8
通讯作者：
Howell, Rebecca
中科院分区：
文献类型：
--
作者：
Han, Tao;Mourtada, Firas;Howell, Rebecca
目的：本研究的目的是验证基于网格的玻尔兹曼解算器acros XB （AXB）在调强放射治疗（IMRT）和体积调制电弧治疗（VMAT）中的剂量学性能。方法：本研究采用放射物理中心（RPC）头颈部（H&N）假体进行所有计算和测量。在Eclipse治疗计划系统（10.0版）中，使用RPC剂量处方规范在RPC H&N幻影上创建临床等效的IMRT和VMAT计划。采用AXB 11.0.03和各向异性分析算法（AAA） 10.0.24计算剂量分布。记录AXB的两种剂量报告模式：培养基（D-m,D-m）中剂量对介质和培养基（D-w,D-m）中剂量对水。每个治疗方案通过瓦里安Clinac iX直线加速器向RPC幻影传送三次，以确保重复性。用热释光剂量计（TLDs）和GafChromic (R) EBT2薄膜分别测量绝对点剂量和平面剂量。采用剖面比较和二维伽玛分析来量化薄膜测量值与AXB和AAA计算剂量分布之间的一致性，并评估AAA和AXB的计算时间。结果：测定的剂量与AAA或AXB计算的剂量吻合良好。在IMRT和VMAT计划中，AAA和AXB计算的剂量都在TLD测量值的5%以内。结果AXB_D-m，D-m（0.1% ~ 3.6%）略好于AAA（0.2% ~ 4.6%）或AXB_D-w，D-m（0.3% ~ 5.1%）。AAA和AXB的伽玛分析均符合RPC 7%/4毫米标准（超过90%通过），而AXB_D-m，D-m在大多数情况下符合5%/3毫米标准。IMRT时，AAA比AXB快2 ~ 3倍，VMAT时，AXB比AAA快4 ~ 6倍。结论：与RPC H&N模型的测量结果相比，AXB具有令人满意的准确性。与AAA相比，AXB结果等于或优于IMRT和VMAT计划的膜测量结果。发现AXB_D-m，D-m报告模式比AXB_D-w，D-m报告模式更接近TLD和薄膜测量。VMAT的AXB计算时间明显短于AAA （x 4）。(C) 2012年美国医学物理学家协会。[http://dx.doi.org/10.1118/1.3692180]
Purpose: The purpose of this study was to verify the dosimetric performance of Acuros XB (AXB), a grid-based Boltzmann solver, in intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT).Methods: The Radiological Physics Center (RPC) head and neck (H&N) phantom was used for all calculations and measurements in this study. Clinically equivalent IMRT and VMAT plans were created on the RPC H&N phantom in the Eclipse treatment planning system (version 10.0) by using RPC dose prescription specifications. The dose distributions were calculated with two different algorithms, AXB 11.0.03 and anisotropic analytical algorithm (AAA) 10.0.24. Two dose report modes of AXB were recorded: dose-to-medium in medium (D-m,D-m) and dose-to-water in medium (D-w,D-m). Each treatment plan was delivered to the RPC phantom three times for reproducibility by using a Varian Clinac iX linear accelerator. Absolute point dose and planar dose were measured with thermoluminescent dosimeters (TLDs) and GafChromic (R) EBT2 film, respectively. Profile comparison and 2D gamma analysis were used to quantify the agreement between the film measurements and the calculated dose distributions from both AXB and AAA. The computation times for AAA and AXB were also evaluated.Results: Good agreement was observed between measured doses and those calculated with AAA or AXB. Both AAA and AXB calculated doses within 5% of TLD measurements in both the IMRT and VMAT plans. Results of AXB_D-m,D-m (0.1% to 3.6%) were slightly better than AAA (0.2% to 4.6%) or AXB_D-w,D-m (0.3% to 5.1%). The gamma analysis for both AAA and AXB met the RPC 7%/4 mm criteria (over 90% passed), whereas AXB_D-m,D-m met 5%/3 mm criteria in most cases. AAA was 2 to 3 times faster than AXB for IMRT, whereas AXB was 4-6 times faster than AAA for VMAT.Conclusions: AXB was found to be satisfactorily accurate when compared to measurements in the RPC H&N phantom. Compared with AAA, AXB results were equal to or better than those obtained with film measurements for IMRT and VMAT plans. The AXB_D-m,D-m reporting mode was found to be closer to TLD and film measurements than was the AXB_D-w,D-m mode. AXB calculation time was found to be significantly shorter (x 4) than AAA for VMAT. (C) 2012 American Association of Physicists in Medicine. [http://dx.doi.org/10.1118/1.3692180]