Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Department of Radiation Oncology, Emory University, Winship Cancer Institute, Atlanta, Georgia, 30322, USA.
Sci Rep. 2019 Mar 5;9(1):3583. doi: 10.1038/s41598-019-40166-9.
The absence of proper nanoscale experimental techniques to investigate the dose-enhancing properties of gold nanoparticles (GNPs) interacting with radiation has prompted the development of various Monte Carlo (MC)-based nanodosimetry techniques that generally require considerable computational knowledge, time and specific tools/platforms. Thus, this study investigated a hybrid computational framework, based on the electron dose point kernel (DPK) method, by combining Geant4 MC simulations with an analytical approach. This hybrid framework was applied to estimate the dose distributions around GNPs due to the secondary electrons emitted from GNPs irradiated by various photon sources. Specifically, the equivalent path length approximation was used to rescale the homogeneous DPKs for heterogeneous GNPs embedded in water/tissue. Compared with Geant4 simulations, the hybrid framework halved calculation time while utilizing fewer computer resources, and also resulted in mean discrepancies less than 20 and 5% for Yb-169 and 6 MV photon irradiation, respectively. Its appropriateness and computational efficiency in handling more complex cases were also demonstrated using an example derived from a transmission electron microscopy image of a cancer cell containing internalized GNPs. Overall, the currently proposed hybrid computational framework can be a practical alternative to full-fledged MC simulations, benefiting a wide range of GNP- and radiation-related applications.
由于缺乏适当的纳米级实验技术来研究金纳米粒子（GNPs）与辐射相互作用的增敏特性，因此开发了各种基于蒙特卡罗（MC）的纳米剂量学技术，这些技术通常需要相当多的计算知识、时间和特定的工具/平台。因此，本研究基于电子剂量点核（DPK）方法，结合 Geant4 MC 模拟和分析方法，研究了一种混合计算框架。该混合框架用于估计由于各种光子源照射的 GNPs 发射的次级电子而在 GNPs 周围的剂量分布。具体来说，使用等效路径长度近似法对水/组织中嵌入的非均匀 GNPs 的均匀 DPK 进行缩放。与 Geant4 模拟相比，混合框架将计算时间缩短了一半，同时使用的计算机资源也减少了，对于 Yb-169 和 6 MV 光子照射，平均差异分别小于 20%和 5%。通过使用源自含有内化 GNPs 的癌细胞的透射电子显微镜图像的示例，还证明了该混合框架在处理更复杂情况时的适当性和计算效率。总体而言，目前提出的混合计算框架可以作为全面 MC 模拟的实用替代方案，有利于广泛的与 GNPs 和辐射相关的应用。
