Validation of GPU-accelerated superposition-convolution dose computations for the Small Animal Radiation Research Platform
Validation of GPU-accelerated superposition-convolution dose computations for the Small Animal Radiation Research Platform
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DOI：
10.1002/mp.12862
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发表时间：
2018-05-01
期刊：
影响因子：
3.8
通讯作者：
Wong, John
中科院分区：
文献类型：
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作者：
Cho, Nathan;Tsiamas, Panagiotis;Wong, John
目的研制小动物辐射研究平台（SARRP），用于星载锥形束CT （CBCT）引导下的适形微辐射研究。将图形处理单元（GPU）加速叠加卷积（SC）剂量计算方法集成到SARRP治疗计划系统（TPS）中。本文通过与EBT2薄膜测量和蒙特卡罗（MC）模拟的比较，验证了SC方法对千伏能量的计算。方法用EGSnrc代码对smc数据进行3 × 10(8) ~ 1.5 × 10(9)历史的模拟，用21个光子能量箱对220 kVp的x射线进行SC方法的模拟。包括塑料水、软木、石墨和铝在内的各种类型的模型被用来包含老鼠器官的密度范围。为了比较，我们分析了SC、MC和膜测量的百分比深度剂量（PDD）。还介绍了SC的横梁（x,y）剂量学曲线和薄膜测量。在铝和石墨的均匀模态中，通过模拟SC和MC，得到了将SC转换为MC剂量-介质的校正因子（CFz），以改进估算。结果SC方法产生的剂量值在膜测量值的5%以内，MC模拟在剖面的平坦区域。由于膜位置的几何不确定性和剂量计算网格的差异等因素，边缘处的剂量精度较低。结论gpu加速叠加-卷积剂量计算方法通过EBT2薄膜测量和MC计算得到了验证。SC方法的计算速度比MC方法快得多，并提供了介质中剂量对水和介质中剂量对介质的计算。
PurposeThe Small Animal Radiation Research Platform (SARRP) has been developed for conformal microirradiation with on-board cone beam CT (CBCT) guidance. The graphics processing unit (GPU)-accelerated Superposition-Convolution (SC) method for dose computation has been integrated into the treatment planning system (TPS) for SARRP. This paper describes the validation of the SC method for the kilovoltage energy by comparing with EBT2 film measurements and Monte Carlo (MC) simulations.MethodsMC data were simulated by EGSnrc code with 3 x 10(8)-1.5 x 10(9) histories, while 21 photon energy bins were used to model the 220 kVp x-rays in the SC method. Various types of phantoms including plastic water, cork, graphite, and aluminum were used to encompass the range of densities of mouse organs. For the comparison, percentage depth dose (PDD) of SC, MC, and film measurements were analyzed. Cross beam (x,y) dosimetric profiles of SC and film measurements are also presented. Correction factors (CFz) to convert SC to MC dose-to-medium are derived from the SC and MC simulations in homogeneous phantoms of aluminum and graphite to improve the estimation.ResultsThe SC method produces dose values that are within 5% of film measurements and MC simulations in the flat regions of the profile. The dose is less accurate at the edges, due to factors such as geometric uncertainties of film placement and difference in dose calculation grids.ConclusionThe GPU-accelerated Superposition-Convolution dose computation method was successfully validated with EBT2 film measurements and MC calculations. The SC method offers much faster computation speed than MC and provides calculations of both dose-to-water in medium and dose-to-medium in medium.