Radiation Dosimetry of Inhaled Radioactive Aerosols: CFPD and MCNP Transport Simulations of Radionuclides in the Lung
Radiation Dosimetry of Inhaled Radioactive Aerosols: CFPD and MCNP Transport Simulations of Radionuclides in the Lung
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DOI：
10.1038/s41598-019-54040-1
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发表时间：
2019-11-25
影响因子：
4.6
通讯作者：
Hecht, Adam
中科院分区：
文献类型：
--
作者：
Talaat, Khaled;Xi, Jinxiang;Hecht, Adam
尽管在研究放射性气溶胶方面做出了广泛的努力，包括研究放射性核素在不同化学基质中在整个身体中的传输，但由于吸入放射性气溶胶而引起的内部器官特定辐射剂量在很大程度上依赖于实验沉积数据和简化的人体模型。计算流体-粒子动力学（CFPD）已被证明是表征上呼吸道气溶胶传输的可靠工具，而基于蒙特卡罗的辐射代码可以准确模拟辐射传输。本研究的目的是通过将CFPD与Monte Carlo N-Particle code（第6版）（MCNP 6）耦合，数值评估环境放射性暴露引起的呼吸道中颗粒衰变的辐射剂量学。一个生理上真实的口肺模型延伸到分叉代G9被用来模拟呼吸道内的气流和颗粒传输。考虑了不同分布的多分散气溶胶，定量了吸入气溶胶在气道内壁的沉积分布。然后将放射性气溶胶的沉积映射登记到基于图像的全身成年男性模型（VIP-Man）的呼吸道，以模拟辐射传输和能量沉积。在MCNP 6中开发了用于几何可视化、空间归一化和源卡定义的计算机代码。比较了不同放射性核素（I-131、Cs-134、Cs-137、Sr-90-Y-90、Ru-103和Pu-239、Pu-240）在辐射注量、能量沉积密度和每次衰变剂量方面的内辐射剂量学空间分布。
Despite extensive efforts in studying radioactive aerosols, including the transmission of radionuclides in different chemical matrices throughout the body, the internal organ-specific radiation dose due to inhaled radioactive aerosols has largely relied on experimental deposition data and simplified human phantoms. Computational fluid-particle dynamics (CFPD) has proven to be a reliable tool in characterizing aerosol transport in the upper airways, while Monte Carlo based radiation codes allow accurate simulation of radiation transport. The objective of this study is to numerically assess the radiation dosimetry due to particles decaying in the respiratory tract from environmental radioactive exposures by coupling CFPD with Monte Carlo N-Particle code, version 6 (MCNP6). A physiologically realistic mouth-lung model extending to the bifurcation generation G9 was used to simulate airflow and particle transport within the respiratory tract. Polydisperse aerosols with different distributions were considered, and deposition distribution of the inhaled aerosols on the internal airway walls was quantified. The deposition mapping of radioactive aerosols was then registered to the respiratory tract of an image-based whole-body adult male model (VIP-Man) to simulate radiation transport and energy deposition. Computer codes were developed for geometry visualization, spatial normalization, and source card definition in MCNP6. Spatial distributions of internal radiation dosimetry were compared for different radionuclides (I-131, Cs-134,Cs-137, Sr-90-Y-90, Ru-103 and Pu-239,Pu-240) in terms of the radiation fluence, energy deposition density, and dose per decay.