共聚焦激光显微内窥成像中PMT与APD探测器性能对比分析  

Comparative Analysis of the Performance of PMT and APD Detectors in Confocal Laser Endomicroscopy

作　　者：侯冠廷 徐宝腾 周伟 刘家林 郭立泉[2] 杨西斌 Hou Guanting;Xu Baoteng;Zhou Wei;Liu Jialin;Guo Liquan;Yang Xibin(Division of Life Sciences and Medicine,School of Biomedical Engineering(Suzhou),University of Science and Technology of China,Suzhou 215163,Jiangsu,China;Center of Light and Health,Suzhou Institute of Biomedical Engineering and Technology,Chinese Academy of Sciences,Suzhou 215163,Jiangsu,China)

机构地区：[1]中国科学技术大学生物医学工程学院(苏州)生命科学与医学部,江苏苏州215163 [2]中国科学院苏州生物医学工程技术研究所光与健康研究中心,江苏苏州215163

出　　处：《光学学报》2023年第11期164-172,共9页Acta Optica Sinica

基　　金：国家重点研发计划(2021YFC2400100);苏州市基础研究计划(szs2020308,SJC2022009)。

摘　　要：共聚焦激光显微内窥镜(CLE)可以进行在体组织显微成像,实现实时病理学诊断,而光电探测器作为CLE系统的核心部件,影响共聚焦图像质量。对比分析光电倍增管(PMT)和雪崩光电二极管(APD)在CLE中的性能表现,建立基于PMT和APD探测电路的CLE成像信号信噪比分析模型,理论分析光电探测器及其放大电路噪声、放大增益、输入光信号等参数对成像信号信噪比的影响。搭建基于PMT和APD双光路探测系统,对均匀荧光溶液和组织样品进行成像。研究结果表明,当样品荧光功率大于10 nW时,所选取PMTSS与APD120A2的输出图像质量接近,信噪比相差小于0.67 dB,APD以更高的性价比实现与PMT相当的成像性能。Objective Confocal laser endomicroscopy(CLE)is an emerging imaging method with a cellular resolution for obtaining histopathological images of structure information on the mucosa in real time.CLE can significantly improve the detection rate of early tumors.Usually,the fluorescence from the tissue prestained with exogenous fluorescent dyes can be detected by the photodetector,which further generates corresponding electrical signals by the photoelectric effect and internal multiplication.Then,the electrical signal can be amplified to form CLE images after analogtodigital conversion.Meanwhile,the output signal of the photodetector is influenced by the noise,which will further affect the quality of the final image.The noise in CLE mostly includes the shot noise introduced by the inherent fluctuation of obtained photons and the dark noise of detectors.So far,many researchers have mainly proposed CLE using mainly two types of photodetectors,such as avalanche photodiode(APD)and photomultiplier tube(PMT).Usually,APD has the advantage of high quantum efficiency and low cost.PMT has the advantage of high gain and low noise.Therefore,the advantages of the selected photodetectors are very different.At present,no researcher has thoroughly investigated the performance differences between APD and PMT.This paper presents a detailed comparative study of APD and PMT performance in CLE.Methods Based on the different working principles of APD and PMT,the quantitative model for output signaltonoise ratio(SNR)in CLE is obtained.The parameters include optical power,quantum efficiency and internal gain of the detector,system bandwidth,photocurrent,dark current,and amplifier noise.All parameters can be obtained from the user manual.Then,we implement a detector performance comparison test,and the light emitted from the LED of 525 nm is used to simulate the fluorescence of samples after passing through a neutral density filter and pinhole.This test not only provides a preliminary understanding of the differences between APD120A2 and PMTSS

关 键 词：医用光学 共聚焦激光显微内窥镜 荧光成像 在体内窥 雪崩光电二极管 光电倍增管 

分 类 号：TH773[机械工程—仪器科学与技术] TN152[机械工程—精密仪器及机械] TN364.2[电子电信—物理电子学]