三维正电子发射断层扫描探测器刻度和深度分辨率测量实验装置

An experimental setup for calibration and depth of interaction resolution measurement of three-dimensional positron emission tomography detector

正电子发射断层扫描(PET)是一种常用的功能分子影像技术,用于多种重大疾病的早期诊断,同时改善PET成像系统的空间分辨率和效率需要使用三维深度测量探测器。本文研制了一台用于该类型探测器刻度和深度分辨率测量的实验装置,以便通过电子符合实现对探测器单一深度的照射。该装置包含一个由可编程逻辑控制器、步进电机以及高精度线性模组构成的移动平台,并采用触摸显示屏实现良好的人机交互。使用一个点放射源,通过一个薄片探测器和将要测量的三维PET探测器之间的符合,实现有选择地对探测器单一深度的照射。对实验装置的定位精度和重复精度进行了测量,结果表明该装置达到0.02 mm的定位和重复精度。最后使用该装置对一个基于LYSO晶体阵列和SiPM光探测器的双端读出PET探测器的深度分辨率进行测量,结果表明该装置完全满足三维PET探测器刻度和深度分辨率测试需要。

Positron emission tomography（PET） is a commonly used functional and molecular imaging technique for the early diagnosis of many major diseases. Three-dimensional depth-encoding detector is required to simultaneously improve the spatial resolution and sensitivity of a PET imaging system. Herein, an experimental setup used for detector calibration and depth of interaction（DOI） resolution measurement is developed so that a specific depth of the detector can be selectively irradiated. The setup consists of a programmable logic controller and a moving platform made of a stepping motor and a high precision linear module. A touch screen is used to realize a good human-computer interaction. A point source and the electric coincidence between a slab detector and the PET detector are used to realize the selectively irradiation of one specific depth of the detector. The positioning and repetition accuracies of the experimental setup are measured and both reach 0.02 mm. Finally, the experimental setup is used to measure the DOI resolution of a three-dimensional PET detector based on dual-ended readout of LYSO crystal array with SiPM photodetectors. The results show that the experimental setup completely fulfills the requirement of detector calibration and DOI resolution measurement for a three-dimensional PET detector.