Characteristics of Annihilation Photons Emitted From New Types of Point-Like $^{22}{\rm Na}$ Radioactive Sources With Symmetric Absorber Designs
Characteristics of Annihilation Photons Emitted From New Types of Point-Like $^{22}{\rm Na}$ Radioactive Sources With Symmetric Absorber Designs
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具有对称吸收体设计的新型点状$^{22}{ m Na}$放射源发射的湮灭光子的特性
DOI：
10.1109/tns.2010.2090898
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发表时间：
2011
影响因子：
1.8
通讯作者：
Hideyuki Takei
中科院分区：
文献类型：
--
作者：
T. Hasegawa;Yasushi Sato;Takahiro Yamada;K. Oda;Y. Wada;Eiji Yoshida;Hideo Murayama;Hideyuki Takei
目的：点状22Na放射源已广泛用于检查测量湮灭光子的辐射探测器和评估PET扫描仪。我们开发了新型的22Na点状放射源，预计在发射光子的角分布上比传统的放射源类型更加对称。本研究的目的是利用蒙特卡罗模拟研究新型22Na点状放射源发射光子的基本特性。方法：采用圆柱形和球形两种新型22Na点源与传统的圆盘型和立方体型两种点源进行比较。利用基于Geant4的蒙特卡罗程序计算了发射的0.511 MeV湮灭光子和1.275 MeV伽马射线的角分布和能谱。结果：新型点状光源发射光子的角分布比传统点状光源更加对称。符合计数的未散射的0.511 MeV湮灭光子对角分布的不对称性在球面和圆柱型中分别为0.1±0.1%和1.6±0.1%，而在立方体和圆盘型中分别为4.1±0.1%和22.6±0.1%。新光源类型在0.511 MeV光峰附近的散射分量分别小于圆盘型和立方体型的2/3和1/2。结论：新型点状22Na源发射光子的角分布更加对称，散射分量更少。它们对于发射光子的对称性至关重要的应用是有用的。
Purpose: Point-like 22Na radioactive sources have been widely used for checking radiation detectors that measure annihilation photons and for evaluating PET scanners. We developed new types of 22Na point-like radioactive sources that are expected to be more symmetric than conventional source types in the angular distribution of the emitted photons. The purpose of this study is to use Monte Carlo simulation to investigate the basic characteristics of the photons emitted from the new type 22Na point-like radioactive sources. Methods: Two new types of 22Na point-like sources, a cylinder type and a sphere type, were considered in comparison with two conventional source types, a disk type and a cube type. The angular distribution and energy spectra of the emitted 0.511 MeV annihilation photons and 1.275 MeV gamma rays were calculated using a Monte Carlo code based on Geant4. Results: The angular distribution of the emitted photons was more symmetric in the new type point-like sources than in the conventional types. The asymmetry of the angular distribution of the unscattered 0.511 MeV annihilation photon pairs counted in coincidence was 0.1 ±0.1% and 1.6±0.1% in the sphere and cylinder types, compared with 4.1±0.1% and 22.6±0.1% for the cube and disk types. The scatter components around the 0.511 MeV photopeaks in the new source types were typically less than 2/3 and 1/2 of those in the disk and cube types, respectively. Conclusion: The new point-like 22Na sources offer a more symmetric angular distribution of the emitted photons with fewer scatter components. They are useful for applications where the symmetry of the emitted photons is crucial.
用于评估 PET 扫描仪的具有多个吸收胶囊的点状放射源
影响因子：
2.6
作者：
T. Hasegawa;E. Yoshida;Y. Sato;K. Oda;T. Yamada;H. Murayama;T. Yamaya;Y. Wada;K. Saito
通讯作者：
K. Saito