Nuclear Techniques ›› 2018, Vol. 41 ›› Issue (4): 40403-040403.doi: 10.11889/j.0253-3219.2018.hjs.41.040403


Effects of light guide thickness on the performance of PET detectors consisting of high-resolution LYSO and SiPM array

ZHENG Yunfei1,2, LI Lanjun1, KUANG Zhonghua2, WANG Xiaohui2, YANG Qian2, SANG Ziru2, REN Ning2, WU San2, FU Xin2, YANG Yongfeng2   

  1. 1. College of Electrical Engineering, University of South China, Hengyang 421001, China;
    2. Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
  • Received:2017-08-24 Revised:2017-09-28 Online:2018-04-10 Published:2018-04-11
  • Supported by:
    Supported by National Natural Science Foundation of China (No.81527804, No.11575285), Natural Science Foundation of Guangdong Province (No.2014A030312006), Basic Research Program of Shenzhen (No.JCYJ20160608153434110)

Abstract: [Background] Positron emission tomography (PET) is a highly sensitive and quantitative molecular imaging modality. PET detector usually consists of a high efficient scintillator array and a position sensitive photodetector or a photodetector array. The spatial resolution of a PET detector is mainly determined by the crystal size of the scintillator array and the quality of the flood histogram of the detector. [Purpose] This paper aims to study the effects of the thickness of the light guide used between the scintillator array and photodetector in the flood histogram and energy spectra of the detector by the lutetium-yttrium oxyorthosilicate (LYSO) scintillator array and silicon photomultiplier (SiPM) array most commonly used in current small animal PET scanners. [Methods] The scintillator array is 12×12 with a crystal size of 0.89 mm×0.89 mm×10 mm. A Hamamatsu 4×4 SiPM array with a 3mm×3 mm pixel size and 0.2 mm gap between pixels is used. The light guide is made of plexiglass with thickness of 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm and 2.5 mm. [Results] The results show that the uniformity of the flood histogram and the capability of resolving the edge crystals improves as the thickness of the light guide increases. The spot size of each individual crystal in the flood histogram increases and the dynamic range of the flood histogram decreases as the thickness of the light guide increases. The light guide has almost no effect on the average photopeak amplitude and energy resolution of the crystal energy spectra. Overall light guide of 1.5 mm provides the best detector performance. [Conclusion] The results of this work provide guidance for developing small animal PET detector using LYSO array with a crystal cross section of about 1 mm×1 mm and SiPM array with a pixel size of 3 mm×3 mm.

Key words: PET detector, Spatial resolution, Light guide, Flood histogram, Energy spectrum

CLC Number: 

  • TL99