Due to their unique properties, gold nanoparticles (GNPs) have been proposed to be used for a wide range of applications, especially for photon radiation therapy. In addition to experimental works, there are worthwhile simulation-based studies focused on the investigation of the effect of parameters governing the dose enhancement due to the presence of GNPs in tissue. In a recently published study, we found that the distribution of GNPs in a single cell plays an important role in nucleus dose enhancement. The present work investigates the sensitivity of dose enhancement of a macroscopic phantom to the modeling of GNPs at the cellular level by using the MCNPX Monte Carlo code. A human eye phantom containing the realistic structures and materials was simulated, with a typical tumor located in its corner filled with three different patterns of distribution of GNPs around the nuclei of the cells. The primary photons emit from a COMS eye plaque brachytherapy containing thirteen 131Cs seeds in the vicinity of the tumor. The study was extended to estimate dose enhancement for various concentration, size, and density of the GNPs accumulated around the nuclei of the tumor. Moreover, the dose delivered to the healthy eye structures for different models has been investigated and discussed. The results show obvious differences between the dose enhancements in the tumor depending on the modeling of GNPs. The results emphasized that an appropriate small-scale model for the distribution of GNPs in the cell would be of high importance to estimate the degree of dose enhancement in a macroscopic phantom to provide a trustworthy prediction to move towards clinical application.

中文翻译：

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用于人眼肿瘤近距离放射治疗的纳米颗粒分布模型。

由于其独特的性能，金纳米颗粒（GNP）已被建议用于广泛的应用，尤其是光子放射疗法。除了实验工作外，还有一些值得进行的基于模拟的研究，这些研究集中于研究由于组织中存在GNP而导致剂量增加的参数的影响。在最近发表的一项研究中，我们发现GNP在单个细胞中的分布在细胞核剂量增加中起着重要作用。本工作研究了使用MCNPX蒙特卡洛代码在细胞水平上宏观模型的剂量增强对GNPs建模的敏感性。模拟了包含现实结构和材料的人眼幻影，其典型的肿瘤位于其角落，充满了细胞核周围GNP的三种不同分布模式。初级光子从COMS眼斑近距离放射疗法中发出，该放射疗法在肿瘤附近包含13个131Cs种子。这项研究被扩展以估计在肿瘤细胞核周围积累的各种浓度，大小和密度的GNP的剂量增加。此外，已经研究和讨论了针对不同模型递送至健康眼结构的剂量。结果显示，取决于GNP的建模，肿瘤剂量增加之间存在明显差异。