Validation of a track repeating algorithm for intensity modulated proton therapy: clinical cases study
Validation of a track repeating algorithm for intensity modulated proton therapy: clinical cases study
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DOI：
10.1088/0031-9155/61/7/2633
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发表时间：
2016-04-07
影响因子：
3.5
通讯作者：
Mohan, Radhe
中科院分区：
文献类型：
--
作者：
Yepes, Pablo P.;Eley, John G.;Mohan, Radhe
蒙特卡罗（MC）方法被认为是计算剂量分布最精确的技术。然而，由于计算时间长，它们难以用于临床或大型回顾性研究。基于MC生成的水中粒子轨迹数据的轨迹重复算法大大加快了剂量计算速度，同时基本上保持了MC的准确性。在本研究中，我们提出了一种用于强度调制质子治疗的有效剂量计算算法的验证，即基于轨迹重复技术的快速剂量计算器（FDC）。我们对23例患者进行FDC算法验证，其中脑7例，头颈6例，肺5例，脊柱1例，骨盆1例，前列腺3例。为了验证，我们将fdc产生的剂量分布与基于GEANT4 （G4）的成熟蒙特卡罗产生的剂量分布进行了比较。我们比较了剂量-体积-直方图和三维伽马图，并分析了一系列剂量学指标。在描述患者的体素化幻影中，超过99%的体素在2%/ 2mm标准下的伽马指数小于1。此外，用FDC计算的剂量学指标与G4计算的剂量学指标相对于规定剂量的差异小于1%。FDC将计算时间从每个质子5毫秒减少到5 μ s左右。
Monte Carlo (MC) methods are acknowledged as the most accurate technique to calculate dose distributions. However, due its lengthy calculation times, they are difficult to utilize in the clinic or for large retrospective studies. Track-repeating algorithms, based on MC-generated particle track data in water, accelerate dose calculations substantially, while essentially preserving the accuracy of MC. In this study, we present the validation of an efficient dose calculation algorithm for intensity modulated proton therapy, the fast dose calculator (FDC), based on a track-repeating technique. We validated the FDC algorithm for 23 patients, which included 7 brain, 6 head-and-neck, 5 lung, 1 spine, 1 pelvis and 3 prostate cases. For validation, we compared FDC-generated dose distributions with those from a full-fledged Monte Carlo based on GEANT4 (G4). We compared dose-volume-histograms, 3D-gammaindices and analyzed a series of dosimetric indices. More than 99% of the voxels in the voxelized phantoms describing the patients have a gamma-index smaller than unity for the 2%/2 mm criteria. In addition the difference relative to the prescribed dose between the dosimetric indices calculated with FDC and G4 is less than 1%. FDC reduces the calculation times from 5 ms per proton to around 5 mu s.