Sensitivity booster for DOI-PET scanner by utilizing Compton scattering events between detector blocks
Sensitivity booster for DOI-PET scanner by utilizing Compton scattering events between detector blocks
复制标题
利用探测器块之间的康普顿散射事件提高 DOI-PET 扫描仪的灵敏度
DOI：
10.1016/j.nima.2014.07.002
复制
发表时间：
2014
影响因子：
1.4
通讯作者：
T. Yamaya
中科院分区：
文献类型：
--
作者：
E. Yoshida;H. Tashima;T. Yamaya
在传统的PET扫描器中，利用有限的能量窗口测量符合事件以检测光电事件，以便拒绝发生在患者中的康普顿散射事件，但是也拒绝在检测器晶体中引起的康普顿散射事件。患者内的散射事件导致散射符合，但是晶体间散射（ICS）事件具有用于确定活性分布的有用信息。一些研究人员已经报道了基于康普顿相机的PET扫描仪用于将ICS追踪到探测器中的可行性。然而，这些扫描仪需要昂贵的半导体探测器来实现高能量分辨率。在Anger型块探测器中，可以在每个相互作用位置上获得与多个探测器相互作用的单光子，并且可以获得与单个探测器中的光电事件相同的完整信息。单探测器中的ICS事件已经被用来获得符合，但是单光子与多个探测器相互作用还没有被用来获得符合。在这项工作中，我们评估了在几种类型的DOI-PET扫描仪中使用康普顿动力学提高灵敏度的效果。所提出的方法有望提高灵敏度，使用符合事件的单光子与多个探测器相互作用，这被确定为第一次相互作用（FI）。可以提高FI估计精度，以根据在符合响应线上计算的康普顿散射角之间的相关性来确定FI有效性。我们模拟了由42个探测器组成的动物PET扫描仪。每个探测器块由三种类型的闪烁体晶体（LSO、GSO和GAGG）组成。在模拟之后，将符合事件添加为用于若干相互作用深度（DOI）分辨率的信息。从模拟结果中，我们得出结论，该方法有望提高灵敏度显着时，闪烁体的有效原子序数低。此外，我们表明，FI估计精度提高，DOI分辨率高。
In a conventional PET scanner, coincidence events are measured with a limited energy window for detection of photoelectric events in order to reject Compton scatter events that occur in a patient, but Compton scatter events caused in detector crystals are also rejected. Scatter events within the patient causes scatter coincidences, but inter crystal scattering (ICS) events have useful information for determining an activity distribution. Some researchers have reported the feasibility of PET scanners based on a Compton camera for tracing ICS into the detector. However, these scanners require expensive semiconductor detectors for high-energy resolution. In the Anger-type block detector, single photons interacting with multiple detectors can be obtained for each interacting position and complete information can be gotten just as for photoelectric events in the single detector. ICS events in the single detector have been used to get coincidence, but single photons interacting with multiple detectors have not been used to get coincidence. In this work, we evaluated effect of sensitivity improvement using Compton kinetics in several types of DOI-PET scanners. The proposed method promises to improve the sensitivity using coincidence events of single photons interacting with multiple detectors, which are identified as the first interaction (FI). FI estimation accuracy can be improved to determine FI validity from the correlation between Compton scatter angles calculated on the coincidence line-of-response. We simulated an animal PET scanner consisting of 42 detectors. Each detector block consists of three types of scintillator crystals (LSO, GSO and GAGG). After the simulation, coincidence events are added as information for several depth-of-interaction (DOI) resolutions. From the simulation results, we concluded the proposed method promises to improve the sensitivity considerably when effective atomic number of a scintillator is low. Also, we showed that FI estimate accuracy is improved, as DOI resolution is high.