Real-time dose computation: GPU-accelerated source modeling and superposition/convolution
Real-time dose computation: GPU-accelerated source modeling and superposition/convolution
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DOI：
10.1118/1.3483785
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发表时间：
2011-01-01
期刊：
影响因子：
3.8
通讯作者：
McNutt, Todd
中科院分区：
文献类型：
--
作者：
Jacques, Robert;Wong, John;McNutt, Todd
目的：利用高度并行的图形处理单元(GPU)将剂量计算加速到交互速率。方法：作者用现代双源模型扩展了他们在GPU加速的叠加/卷积方面的工作，并提高了性能。主源算法支持聚焦叶端和非对称圆形叶端。Extra-Focus算法使用离散化的、各向同性的面源，并模拟多叶准直器的叶高效果。静态光束修改器的光谱效应和衰减效应被整合到每个源的光谱函数中。引入了弧形叠加和三角洲叠加的概念。圆弧叠加利用单位质量释放的总能量(Terma)的单独角度采样和叠加计算来提高精度和性能。增量叠加允许高效地计算单个光束的变化。作者扩展了他们的多分辨率叠加的概念，以包括核倾斜。多分辨率叠加近似于立体角度光线跟踪，以较小的精度损失改善了性能和可伸缩性。叠加/卷积是利用逆累积-累积核和精确的射线路径跟踪实现的。使用多个核射线采样进行精度分析，包括有无核倾斜和多分辨率叠加。结果：源模型性能
Purpose: To accelerate dose calculation to interactive rates using highly parallel graphics processing units (GPUs).Methods: The authors have extended their prior work in GPU-accelerated superposition/convolution with a modern dual-source model and have enhanced performance. The primary source algorithm supports both focused leaf ends and asymmetric rounded leaf ends. The extra-focal algorithm uses a discretized, isotropic area source and models multileaf collimator leaf height effects. The spectral and attenuation effects of static beam modifiers were integrated into each source's spectral function. The authors introduce the concepts of arc superposition and delta superposition. Arc superposition utilizes separate angular sampling for the total energy released per unit mass (TERMA) and superposition computations to increase accuracy and performance. Delta superposition allows single beamlet changes to be computed efficiently. The authors extended their concept of multi-resolution superposition to include kernel tilting. Multi-resolution superposition approximates solid angle ray-tracing, improving performance and scalability with a minor loss in accuracy. Superposition/convolution was implemented using the inverse cumulative-cumulative kernel and exact radiological path ray-tracing. The accuracy analyses were performed using multiple kernel ray samplings, both with and without kernel tilting and multi-resolution superposition.Results: Source model performance was