论文标题
使用Geant4开发用于Halcyon的完整蒙特卡洛治疗剂量计算工具包
Development of a Full Monte Carlo Therapeutic Dose Calculation Toolkit for Halcyon Using Geant4
论文作者
论文摘要
目的：开发蒙特卡洛（MC）治疗剂量计算工具包，该工具包最近在Geant4（版本10.7）（版本10.7）中用于放射治疗计划的二级剂量验证。方法：对于Halcyon（Varian Medical Systems），对DSMLC进行了建模，并使用Geant4模拟了DSMLC和患者幻影中的辐射运输。从DSMLC上方的Linac头的相位空间文件中对辐射源进行采样。使用基于云的蒙特卡洛（MC）模拟器VirtualInac（VL）提供的相位空间文件。不同平方场宽度（2x2、4x4、6x6、8x8、10x10、20x20和28x28 cm2）的剂量谱图，即对实验轮廓进行模拟并进行比较。还使用开发的工具包计算了两个解剖部位（前列腺和大脑）中的IMRT（强度调制辐射疗法）计划，并与TPS计算的剂量进行了比较（Acuros，Eclipse 15.6）。 3D剂量差和3D伽马分析用于评估与TPS计算剂量相比的模拟精度。结果：水幻象中的模拟侧剂量曲线和PDD曲线与所有模拟场大小的测量值非常匹配，相对差 +-2％。对于前列腺和大脑IMRT计划，模拟剂量与TPS计算的剂量显示出良好的一致性。两个前列腺和大脑计划的3D Gamma通过率（3％/3mm）分别为98.08％和95.4％。结论：Halcyon开发的全MC剂量计算工具包在水幻影和患者CT幻影中的剂量计算方面表现良好。开发的工具包显示了IMRT未来次级剂量计算的有希望的可能性，并用作Halcyon的临床质量保证（QA）工具。
Purpose: To develop a Monte Carlo (MC) therapeutic dose calculation toolkit of a recently released ring gantry linac in Geant4 (Version 10.7) for secondary dose validation of radiotherapy plan. Methods: For the Halcyon (Varian Medical Systems), the DSMLC was modeled and radiation transport in DSMLC and patient phantom was simulated using Geant4. Radiation source was sampled from a phase space file for linac head above the DSMLC. The phase space file was obtained using a cloud-based Monte Carlo (MC) simulator, VirtuaLinac (VL) provide by Varian. Dosimetric profiles for different square field widths (2x2, 4x4, 6x6, 8x8, 10x10, 20x20, and 28x28 cm2), i.e., percent depth dose (PDD) curves and lateral profiles are simulated and compared against the experimental profiles. IMRT (intensity modulated radiation therapy) plans in two anatomical sites (prostate and brain) were also calculated using the developed toolkit and compared against the TPS calculated dose (Acuros, Eclipse 15.6). 3D dose difference and 3D gamma analysis were used to evaluate the simulation accuracy compared against the TPS calculated dose. Results: The simulated lateral dose profiles and PDD curves in water phantom match well with the measured ones for all the simulated field sizes with relative difference +-2%. For the prostate and brain IMRT plans, the simulated dose showed a good agreement with the TPS calculated dose. The 3D gamma pass rate (3%/3mm) are 98.08% and 95.4% for the two prostate and brain plans, respectively. Conclusion: The developed full MC dose calculation toolkit for Halcyon performs well in dose calculations in water phantom and patient CT phantom. The developed toolkit shows promising possibility for future secondary dose calculation for IMRT and serve as clinical quality assurance (QA) tool for Halcyon.
