NSECT的锗酸铋阵列相邻信号叠加算法模拟研究

Summing adjacent signals from BGO array in neutron stimulated emission computed tomography

由于受激元素所辐射的γ光子能量范围主要集中在100keV^6 MeV之间,因此通过基于此能量范围的γ射线源模拟实验研究了采用锗酸铋(BGO)阵列相邻信号叠加实现能量高分辨率的新方法并分析比较了其性能。结果显示:对于较高能的γ光子,若仅使用单根BGO晶体产生的信号时不可能得到较好的能量分辨率;而当使用BGO阵列将该单晶体产生的信号与相邻晶体产生信号相加,则能谱质量会变得更佳。对于能量分辨率为90keV的能量窗,通过模拟得到平均固有空间分辨率为3.938mm(FWHM)。

Neutron stimulated emission computed tomography （NSECT） is a new approach for biological spectroscopy and imaging. Since the gamma-ray photons emitted from stimulated element have energies from 100 keV to about 6 MeV, previous reports have proposed that the projection path can be defined by the neutron beam. In this paper, a good energy resolution method has been applied, whose performance is analysed through simulations. Using signals from a single BGO crystal, it is impossible to achieve good energy resolution for such high-energy photons. But when summing additional signals from adjacent crystals, the energy spectrum becomes much better. Using an energy window with energy resolution of 90 keV, an average intrinsic spatial resolution of 3. 938 mm FWHM is obtained.