Optimizing Compton camera geometries.
Optimizing Compton camera geometries.
复制标题
优化康普顿相机的几何形状。
DOI：
10.1088/0031-9155/49/8/002
复制
发表时间：
2004
影响因子：
3.5
通讯作者：
Zubal,George
中科院分区：
文献类型：
--
作者：
Chelikani,Sudhakar;Gore,John;Zubal,George
康普顿相机承诺改善核医学成像的特性，其中机械准直被电子准直取代。这导致了敏感度的巨大提高，从而减少了患者需要接受的辐射剂量。提高灵敏度的设计修改总是会影响分辨率。当前项目的范围是确定在这两个特性之间取得平衡的康普顿相机的最佳设计和配置。以摄像机几何形状为优化参数，模拟了光子通量从光源到探测器的传输过程。采用两种不同的玻耳兹曼光子输运方程，分别考虑和不考虑光子偏振，对通量进行模拟。还包括了能谱的多普勒展宽。模拟是在使用GEANT4的蒙特卡罗框架中完成的。模拟了~(99m)Tc和~(18)F的两个临床相关能量140keV和511keV。康普顿相机的感光度比传统相机提高了100倍。多普勒展宽和偏振对相机的灵敏度都没有显著影响。然而，相机的空间分辨率受到这些过程的影响。多普勒展宽对空间分辨率有不利影响，但在重建算法中考虑了偏振的影响，提高了分辨率。
Compton cameras promise to improve the characteristics of nuclear medicine imaging, wherein mechanical collimation is replaced with electronic collimation. This leads to huge gains in sensitivity and, consequently, a reduction in the radiation dosage that needs to be administered to the patient. Design modifications that improve the sensitivity invariably compromise resolution. The scope of the current project was to determine an optimal design and configuration of a Compton camera that strikes a balance between these two properties. Transport of the photon flux from the source to the detectors was simulated with the camera geometry serving as the parameter to be optimized. Two variations of the Boltzmann photon transport equation, with and without photon polarization, were employed to model the flux. Doppler broadening of the energy spectra was also included. The simulation was done in a Monte Carlo framework using GEANT4. Two clinically relevant energies, 140 keV and 511 keV, corresponding to 99m Tc and 18 F were simulated. The gain in the sensitivity for the Compton camera over the conventional camera was 100 fold. Neither Doppler broadening nor polarization had any significant effect on the sensitivity of the camera. However, the spatial resolution of the camera was affected by these processes. Doppler broadening had a deleterious effect on the spatial resolution, but polarization improved the resolution when accounted for in the reconstruction algorithm.