Two-crossed-polarizers based optical property modulation method for ionizing radiation detection for positron emission tomography.
Two-crossed-polarizers based optical property modulation method for ionizing radiation detection for positron emission tomography.
复制标题
基于两正交偏振器的光学特性调制方法，用于正电子发射断层扫描的电离辐射检测。
DOI：
10.1088/1361-6560/ab23cb
复制
发表时间：
2019
影响因子：
3.5
通讯作者：
Xu,Jianfeng
中科院分区：
文献类型：
--
作者：
Wang,Yuli;Li,Yingjie;Yi,Fei;Li,Junyu;Xie,Siwei;Peng,Qiyu;Xu,Jianfeng
最近的研究表明，波克尔斯效应和光学泵浦探针测量可以作为一种新的方法，用于511 keV电离辐射光子检测正电子发射断层扫描（PET），这可能会克服大约100 ps的符合时间分辨率的固有物理限制（Tao et al . 2016 Phys）。医学。生物学。61 7600-22)。在本文中，我们接受了这一观察结果，并引入了一种基于双交叉偏振器的装置来实现类似的检测概念，这是一种更简单、更紧凑的装置，具有与先前提出的工作中使用的装置相当的电离辐射检测能力。我们用铌酸锂（linbo3）和碲化镉（CdTe）探测器晶体评估了我们的实验装置的性能，并讨论了理想探测器晶体的期望性能。利用基于双交叉偏振器的方法，可以在LiNbO 3和CdTe中检测到511 keV光子诱导的调制信号，信号幅度可重复，而在相同偏置电压下，CdTe对511 keV光子的检测灵敏度比LiNbO 3高8倍，表明CdTe具有高有效Z数和高密度特性，而LiNbO 3具有更短的载流子寿命和更低的载流子迁移率。在饱和前，调制信号强度随偏置电压呈线性增加。由于LiNbO 3的高电阻率可以降低探测器中的暗电流，在2000 V之后，其调制信号强度继续增加，而低电阻率CdTe的调制信号在高于1200 V的偏置电压下趋于饱和。因此，进一步提高探测器晶体（特别是linbo3）的偏置电压可以增强调制强度，提高对湮灭光子的探测灵敏度。
Recent work shows that Pockels effect and optics pump-probe measurement could be utilized as a novel method for 511 keV ionizing radiation photon detection for positron emission tomography (PET) which could potentially overcome the inherent physical limitation for coincidence time resolution of around 100 ps (Tao et al 2016 Phys. Med. Biol. 61 7600–22). In this paper, we embrace this observation and introduce a two-crossed-polarizers based setup to achieve similar detection concept, which is a simpler and more compact setup with comparable ionizing radiation detection capability as the setup used in the previously proposed work. We evaluated the performance of our experimental setup with Lithium Niobate (LiNbO 3) and Cadmium Telluride (CdTe) detector crystals, and the desired properties of an ideal detector crystal were discussed. The modulation signal induced by 511 keV photons in both LiNbO 3 and CdTe can be detected with repeatable signal amplitude using two-crossed-polarizers based method, while CdTe could provide eight times higher detection sensitivity to 511 keV photons than LiNbO 3 under the same bias voltage, suggesting high effective Z number and high density properties of CdTe, as well as a shorter carrier lifetime and lower carrier mobility of LiNbO 3. In addition, the strength of modulation signal increased linearly with bias voltage before saturation. The modulation signal strength in LiNbO 3 continued to increase after 2000 V due to its high resistivity which could reduce the dark current in the detector, while the modulation signal of CdTe with low resistivity tended to be saturated at a bias voltage higher than 1200 V. Therefore, further increasing the bias voltage for detector crystals (especially for LiNbO 3) may enhance the modulation strength and improve the detection sensitivity for annihilation photons.