Nanodosimetric effects of gold nanoparticles in megavoltage radiation therapy
Nanodosimetric effects of gold nanoparticles in megavoltage radiation therapy
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DOI：
10.1016/j.radonc.2011.08.026
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发表时间：
2011-09-01
影响因子：
5.7
通讯作者：
Currell, Fred J.
中科院分区：
文献类型：
--
作者：
McMahon, Stephen J.;Hyland, Wendy B.;Currell, Fred J.
背景和目的：金纳米颗粒(GNPs)由于其高密度和高能量吸收系数而增加了肿瘤的剂量，使其成为一种潜在的放射增敏剂。然而，实验已经观察到辐射敏感性明显大于单独剂量的增加，包括在金的相对能量吸收最低的兆伏能量下。这项工作调查了GNPs是否在亚细胞尺度上产生剂量不均匀，结合细胞存活的非线性剂量依赖关系，成为兆伏能量下放射增敏的来源。材料和方法：采用蒙特卡罗模拟计算纳米尺度上单个GNP附近的剂量。然后对2 nm GNPs照射的MDA-MB-231细胞进行了纳米剂量分布的模拟，并与实验结果进行了比较。结果：GNPs暴露在兆伏特电压照射下，周围发生了显著的剂量不均匀。当使用局部效应模型分析时，这些不均匀导致了显著的辐射增敏，这与实验结果一致。结论：这项工作表明，GNP的辐射增敏是由纳米尺度上的剂量不均匀驱动的，而不是整个细胞上的剂量变化，这可能有助于在兆伏和千伏实验中观察到类似的辐射增敏。这些不均匀性的短范围和不同细胞中增强的差异表明，亚细胞定位在确定GNP的放射敏感性方面很重要。(C)2011爱思唯尔爱尔兰有限公司。保留所有权利。放射治疗和肿瘤学100(2011)412-416
Background and purpose: The addition of gold nanoparticles (GNPs) to tumours leads to an increase in dose due to their high density and energy absorption coefficient, making it a potential radiosensitiser. However, experiments have observed radiosensitisations significantly larger than the increase in dose alone, including at megavoltage energies where gold's relative energy absorption is lowest. This work investigates whether GNPs create dose inhomogeneities on a sub-cellular scale which combine with non-linear dose dependence of cell survival to be the source of radiosensitisation at megavoltage energies.Materials and methods: Monte Carlo simulations were carried out to calculate dose in the vicinity of a single GNP on the nanoscale. The effect of this nanoscale dose distribution was then modelled for MDA-MB-231 cells exposed to 2 nm GNPs, and compared to experimental results.Results: Dramatic dose inhomogeneities occur around GNPs exposed to megavoltage radiation. When analysed using the Local Effect Model, these inhomogeneities lead to significant radiosensitisation, in agreement with experimental results.Conclusions: This work suggests that GNP radiosensitisation is driven by inhomogeneities in dose on the nanoscale, rather than changes in dose over the entire cell, which may contribute to the similar radiosensitisation observed in megavoltage and kilovoltage experiments. The short range of these inhomogeneities and the variation in enhancement in different cells suggests sub-cellular localisation is important in determining GNP radiosensitisation. (C) 2011 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 100 (2011) 412-416