Elemental quantification through gamma-stimulated spectroscopy: An NRF simulation in GEANT4
Elemental quantification through gamma-stimulated spectroscopy: An NRF simulation in GEANT4
复制标题
通过伽马刺激光谱进行元素定量：GEANT4 中的 NRF 模拟
DOI：
10.1109/nssmic.2011.6153823
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
G. Agasthya
中科院分区：
文献类型：
--
作者：
A. Kapadia;Q. Ye;G. Agasthya
自2008年以来，我们一直在开发一种新的方法来量化人体中天然存在的元素。这项技术被称为伽马受激光谱学（GSS），它使用高能调谐伽马射线束通过核共振荧光（NRF）刺激体内特定稳定同位素的选定能级。这种选择性激发可用于检测在患病组织和健康组织之间表现出元素浓度差异的各种人类病症。在以前的工作中，我们已经开发了一个原型GSS设备使用的自由电子激光（FEL）源在杜克大学，并证明了在水中的铁的选择性激发。在这里，我们描述了一个GEANT4模拟的GSS系统，包括NRF过程的建模的发展。在GEANT4中模拟单色准直伽马源、虚拟伽马射线探测器和含水铁铜体模。通过创建一个新的NRF过程类来模拟NRF过程，该过程类计算相互作用截面和核去激发数据。模拟进行了测试，在两个源能量（846.7千电子伏和3448.41千电子伏）对应于自然铁的可激发能级。由此产生的光谱显示出准确的伽马能量响应和发射模式，并表现出良好的相关性之间的模拟和测量的铁浓度。在对实验数据进行基准测试之后，模拟将为GEANT4中的NRF过程建模提供准确的工具，并将用于指导临床GSS系统的开发。
Since 2008, we have been developing a new method for the quantification of naturally occurring elements in the human body. The technique, called gamma-stimulated spectroscopy (GSS), uses high-energy, tuned gamma-ray beams to stimulate selected energy levels in specific stable isotopes in the body through nuclear resonance fluorescence (NRF). Such selective excitation can be used to detect a variety of human disorders that exhibit differences in element concentration between diseased and healthy tissue. In previous work, we have developed a prototype GSS device using the free-electron-laser (FEL) source at Duke University and demonstrated the selective excitation of iron in water. Here we describe the development of a GEANT4 simulation of the GSS system including the modeling of the NRF process. A monochromatic, collimated gamma source, virtual gamma-ray detectors, and an aqueous iron-copper phantom were simulated in GEANT4. The NRF process was modeled by creating a new NRF process class that calculated the interaction cross-section and the nuclear deexcitation data. The simulation was tested at two source energies (846.7 keV and 3448.41 keV) corresponding to excitable energy levels in natural iron. The resulting spectra showed accurate gamma energy response and emission patterns and exhibited excellent correlation between the simulated and the measured iron concentration. Following benchmarking against experimental data, the simulation will provide an accurate tool for modeling NRF processes in GEANT4 and will be used to guide the development of the clinical GSS system.