基于蛇形光路的PET探测器作用深度提取方法

为实现正电子发射断层成像(Positron Emission Tomography,PET)探测器的作用深度(Depth Of Interaction,DOI)信息获取,本文提出一种基于分光技术的探测器设计方案.探测器采用晶体单元与硅光电倍增管(Silicon Photomultiplier,SiPM)一对一耦合、蛇形光路的设计和单端Anger加权读出方法进行DOI解码.基于GATE软件进行蒙特卡罗模拟,建立8×1的LSO晶体阵列(单根晶体尺寸3.1×3.1×20mm3);模拟泛场照射获取位置查找表;并进行不同深度的模拟,获得各晶体在各深度的空间分辨率.结果显示所模拟的探测器模块DOI分辨率在1.0~6.7mm之间,平均值为3.2mm.本文提出的基于蛇形光路的PET探测器方案能在维持系统成本和复杂度的前提下实现DOI解码,提升PET系统的成像性能.

Extraction of the Depth-of-interaction for PET Detectors Based on a Serpentine-light-path Design

To obtain the Depth Of Interaction (DOI) information for Positron Emission Tomography (PET),we proposed a novel detector design based on the light sharing technique.The detector used scintillators and silicon photomultipliers (SiPMs) with one to one coupling,employed the serpentinelight-path reflector scheme and the single-end Anger logic readout technique.Monte Carlo simulations were carried out to verify the design via GATE toolkit.An 8 × 1 LSO array with a crystal size of 3.1 × 3.1× 20 mm3 was built.A flood source for generating position look-up table and five beam sources irradiating at different depths of the crystals were simulated and then calculated.The result shows that the average DOI resolution is 3.2 mm (ranging from 1 to 7 mm).In conclusion,we propose a novel detector design based on a serpentine-light-path scheme to realize DOI decoding which is a low-cost and practical direction for clinical PET systems.