A study on a nonlinear least-squares fitting method for 3D positioning of gamma rays based onmonolithic crystal and SiPM array  

作　　者：Hongfan Zhang Rong Zhou Rutao Yao Chaowen Yang Su Xu Yijia Shu Bing Jiang Lang Liu 

机构地区：[1]Sichuan Management and Monitoring Center Station of Radioactive Environment,Chengdu 611139,Sichuan province,China [2]Key Laboratory of Radiation Physics and Technology,College of Physics,Ministry of Education,Sichuan University,Chengdu 610064,Sichuan province,China [3]Department of Nuclear Medicine,Department of Biophysics,Department of Pharmacy Practice,School of Medicine and Biomedical Sciences,University at Buffalo,SUNY,Buffalo,NY 14214,USA [4]Key Laboratory of Radiation Physics and Technology,Department of Nuclear Engineering and Technology,College of Physical Science and Technology,Ministry of Education,Sichuan University,Chengdu 610064,Sichuan province,China

出　　处：《Radiation Detection Technology and Methods》2022年第3期375-390,共16页辐射探测技术与方法（英文）

基　　金：supported in part by National Natural Science Foundation of China(No.11205108,No.11475121);Excellent Youth Found of Sichuan University(No.2016SCU04A13)and China Scholarship Council.

摘　　要：Purpose In order to improve imaging quality of position sensitive gamma detectors,many research groups especially those interested in positron emission tomography(PET)imaging have done many efforts to develop detecting method with depth of interaction(DOI)capability.A detector with a monolithic lutetium yttrium silicate(LYSO)crystal and an silicon photomultiplier(SiPM)array is constructed by our group for DOI detecting research.Methods 3D interaction coordinates of gamma rays are estimated by a nonlinear least-squares fitting method based on an analytical model in which photon number collected by an SiPM pixel is related to solid angle seen from gamma interaction point and boundary reflection.We have assessed the gamma positioning performance of our detector by projecting a line-like 137Cs gamma beam on top and side surface of the crystal.Virtual source and solid angle factors in the analytical model have also been tested for the best performance both in simulations and experiments.Results Good gamma positioning images are demonstrated with both X–Y and DOI positioning resolutions close to 2 mm full width at half maximum(FWHM).Conclusion Comparing to former DOI methods,the performance of our DOI detector can be called competitive in positioning resolution,construction cost and difficulty of assembling.

关 键 词：PET DOI Monolithic crystal SIPM 

分 类 号：O57[理学—粒子物理与原子核物理]