Effect of CZT system characteristics on Compton scatter event recovery.
Effect of CZT system characteristics on Compton scatter event recovery.
复制标题
CZT 系统特性对康普顿散射事件恢复的影响。
DOI：
10.1109/trpms.2019.2915054
复制
发表时间：
2020
影响因子：
4.4
通讯作者：
Abbaszadeh,Shiva
中科院分区：
文献类型：
--
作者：
Yang,Sheng;Li,Mohan;Reed,Michael;Hugg,James;Chen,Henry;Abbaszadeh,Shiva
提高511kev光子探测灵敏度是正电子发射断层扫描（PET）系统设计者的共同目标。提高灵敏度的一个有吸引力的方法是恢复通常被拒绝的事件。康普顿散射的运动学可以通过方向差角（DDA）来恢复响应线。DDA的不确定度由系统的能量和空间分辨率决定。本文在前人研究的基础上，对能量分辨率分别为1%、4%和6%以及不同空间分辨率的小动物碲化镉锌PET系统的性能进行了评价，以指导新的设计工作。考虑了受计数统计和电子噪声限制的能量分辨率设计。研究了修正常规能量窗和DDA不确定度对DDA的影响。对于能量分辨率为4%且受电子噪声限制的系统，当能量下限从471 keV增加到493 keV时，噪声等效计数的优点值增加了65%。如果全系统能量分辨率在511 keV时低于全宽度一半最大值的4%，那么小于1mm的像素尺寸在减少总角度不确定性方面的效果非常有限。对于能量分辨率为1%的系统，随着空间分辨率从1mm提高到0.5 mm，噪比增加了9%。
Improving 511 keV photon detection sensitivity is a common goal for positron emission tomography (PET) system designers. One attractive approach to increase sensitivity is recovering events that are normally rejected. The kinematics of Compton scattering can be used to recover the line of response through direction difference angle (DDA). The uncertainty of DDA is determined by the energy and spatial resolution of a system. In this paper, we evaluated the performance of small animal cadmium zinc telluride-based PET systems with energy resolution of 1%, 4%, and 6% and different spatial resolution based on prior work for guiding new design efforts. Designs with energy resolution limited by counting statistics and by electronic noise were considered. The influence of modifying the conventional energy window and uncertainty of DDA was investigated. For a system with 4% energy resolution and limited by electronic noise, the figure of merit of noise equivalent count increases by 65% as the lower energy bound increases from 471 to 493 keV. If the system-wide energy resolution becomes worse than 4% of the full width half maximum at 511 keV, going to a pixel size finer than 1 mm has very limited effect in reducing total angular uncertainty. For a system with 1% energy resolution, as the spatial resolution improves from 1 mm to 0.5 mm, the contrast-to-noise ratio increases by 9%.