Physikalisch-Technische Bundesanstalt, Braunschweig and Berlin, Germany; European Radiation Dosimetry Group (EURADOS) e.V, Neuherberg, Germany.
Institute of Radiation Medicine, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany; European Radiation Dosimetry Group (EURADOS) e.V, Neuherberg, Germany.
Phys Med. 2021 Apr;84:241-253. doi: 10.1016/j.ejmp.2021.03.005. Epub 2021 Mar 23.
Results of a Monte Carlo code intercomparison exercise for simulations of the dose enhancement from a gold nanoparticle (GNP) irradiated by X-rays have been recently reported. To highlight potential differences between codes, the dose enhancement ratios (DERs) were shown for the narrow-beam geometry used in the simulations, which leads to values significantly higher than unity over distances in the order of several tens of micrometers from the GNP surface. As it has come to our attention that the figures in our paper have given rise to misinterpretation as showing 'the' DERs of GNPs under diagnostic X-ray irradiation, this article presents estimates of the DERs that would have been obtained with realistic radiation field extensions and presence of secondary particle equilibrium (SPE). These DER values are much smaller than those for a narrow-beam irradiation shown in our paper, and significant dose enhancement is only found within a few hundred nanometers around the GNP. The approach used to obtain these estimates required the development of a methodology to identify and, where possible, correct results from simulations whose implementation deviated from the initial exercise definition. Based on this methodology, literature on Monte Carlo simulated DERs has been critically assessed.
最近报道了一项用于模拟 X 射线辐照金纳米颗粒（GNP）引起的剂量增强的蒙特卡罗代码比对研究的结果。为了突出代码之间的潜在差异，显示了模拟中使用的窄束几何形状的剂量增强比（DER），这些结果在距 GNP 表面数十微米的距离内显著高于 1。由于我们注意到我们论文中的图引起了误解，以为它们显示了诊断 X 射线辐照下 GNP 的“DER”，因此本文提出了考虑到实际辐射场扩展和二次粒子平衡（SPE）存在时的 DER 估计值。这些 DER 值比我们论文中显示的窄束辐照的 DER 值小得多，并且仅在 GNP 周围几百纳米范围内才发现显著的剂量增强。获得这些估计值的方法需要开发一种方法来识别并在可能的情况下纠正偏离初始研究定义的模拟结果。基于这种方法，对蒙特卡罗模拟 DER 的文献进行了严格评估。
