生物医学光子学与激光散斑成像科学探究.pptx

Lab of biomedical photonicshttp:/Laser Speckle Contrast ImagingTheory,Instrumentation and ApplicationsDepartment of Biomedical EngineeringLab of Biomedical PhotonicsBiomedical Optics TopicLab of biomedical photonicshttp:/02 May 2024Page 2Introduction to Biomedical Optics Diffuse Optical Tomography(DOT)Photoacoustic Imaging(PAI)Multi-spectral Optical Intrinsic Signal Imaging Molecular Imaging Ultrafast Photography High Resolution Altas of Mouse Brain Laser Speckle Contrast Imaging Theory Instrumentation ApplicationsOulineLab of biomedical photonicshttp:/02 May 2024Page 3General optics theoryTherapeutic applications of lightDiagnostic optical methods Medical optical imaging is the use of light as an investigational imaging technique for medical applications.Biomedical OpticsLab of biomedical photonicshttp:/02 May 2024Page 4Diffuse Optical Tomography(DOT)Nat Photonics.2014 June;8(6):Lab of biomedical photonicshttp:/02 May 2024Page 5Diffuse Optical Tomography(DOT)Lab of biomedical photonicshttp:/02 May 2024Page 6Photoacoustic Imaging(PAI)Lab of biomedical photonicshttp:/02 May 2024Page 7Photoacoustic Imaging(PAI)Lab of biomedical photonicshttp:/02 May 2024Page 8Photoacoustic Imaging(PAI)Lab of biomedical photonicshttp:/02 May 2024Page 9Multi-spectral Optical Intrinsic Signal ImagingLab of biomedical photonicshttp:/02 May 2024Page 10Multi-spectral Optical Intrinsic Signal ImagingSimultaneous detection of hemodynamics,mitochondrial metabolism and light scattering changes during cortical spreading depression in rats based on multi-sNeuroImageVolume 76,1 August 2013,Pages 7080Lab of biomedical photonicshttp:/02 May 2024Page 11Molecular imagingMarina V Backer,NATURE MEDICINE 2007,13Lab of biomedical photonicshttp:/02 May 2024Page 12Molecular imagingW.T.Li,BIOMEDICAL OPTICS EXPRESS,2014,2679L.M.Nie,ACS Nano,2014Lab of biomedical photonicshttp:/02 May 2024Page 13Molecular imagingIn vivo photoacoustic imaging of brain injury and rehabilitation by NIR dye labeled mesenchymal stem cells with enhanced brain barrier permeabilityWeitaoLi,#,HongkeWang,#,JingLv,#,RongheChen,YuLiu,YaPeng,andLimingNie,*Lab of biomedical photonicshttp:/02 May 2024Page 14Ultrafast Photography L Gao et al.Nature 516,74-77(2014)Lab of biomedical photonicshttp:/02 May 2024Page 15Ultrafast Photography high speed digital image sequenceLab of biomedical photonicshttp:/02 May 2024Page 16High Resolution Altas of Mouse BrainLab of biomedical photonicshttp:/02 May 2024Page 17High Resolution Altas of Mouse Brain Li A,2010,Science,330(6009)Lab of biomedical photonicshttp:/02 May 2024Page 18Laser Speckle Contrast Imaging Theory Instrumentation ApplicationsOulineLab of biomedical photonicshttp:/02 May 2024Page 19What is laser speckle contrast imaging?J.Senarathna,IEEE Reviews in Biomedical Engineering,6,2013Lab of biomedical photonicshttp:/02 May 2024Page 20When coherent light scatters from a random medium,the scattered light produces a random interference pattern called speckle.Speckle Definition*DA.Boas,Journal of Biomedical Optics,2010,15(1)#D.Briers,Journal of Biomedical Optics,2013,18(6)Lab of biomedical photonicshttp:/02 May 2024Page 21SpeckleJ.Senarathna,IEEE REVIEWS IN BIOMEDICAL ENGINEERING,6,2013Lab of biomedical photonicshttp:/02 May 2024Page 22The theoretical basis for analyzing speckle intensity fluctuations dates back to the late 1960s with the development of dynamic light scattering.History-1960R.Pecora,Annual Review of Biophysics and Bioengineering,1972Lab of biomedical photonicshttp:/02 May 2024Page 23There was extensive activity in the 1970s rigorously relating speckle temporal dynamics to various forms of particle dynamics in dilute single-scattering suspensions.History-1970In vivo evaluation of microcirculation by coherent light scatteringNature 254,56-58(06 March 1975)Lab of biomedical photonicshttp:/02 May 2024Page 24A solution was presented in the 1980s using a camera to obtain a quick snapshot image of a time-integrated speckle pattern,History-1980A.Fercher,Optics Communications 37(5),1981Lab of biomedical photonicshttp:/02 May 2024Page 25This method,laser speckle contrast imaging(LSCI),was advanced in the 1990s for imaging blood flow in the retina and skin with the availability of faster digital acquisition and processing technologies.History-1990Lab of biomedical photonicshttp:/02 May 2024Page 26The speckle image of 2-D maps of blood flow can be obtained with very high spatial and temporal resolution by using a CCD camera and quantifying the spatial blurring of the speckle pattern.To quantify the blurring of the speckles,the speckle contrast,defined as the ratio of the standard deviation to the mean intensity,is computed as,Theoretical BackgroundNote that we use s to refer to the spatial standard deviation of the speckle intensity,K is the spatial speckle contrast,and is the average intensity of speckle image.Lab of biomedical photonicshttp:/02 May 2024Page 27激光散斑衬比成像基本原理Lab of biomedical photonicshttp:/02 May 2024Page 28This gives a speckle contrastTheoretical BackgroundLab of biomedical photonicshttp:/02 May 2024Page 29Modulate of LSCI(a)Spatial Speckle Contrast(b)Temporal Speckle Contrast(c)Spatial versus Temporal Speckle ContrastLab of biomedical photonicshttp:/02 May 2024Page 30激光散斑空间衬比分析如图所示，图中的每个方格代表一个 CCD图像上的像素点，第一个 NsNs 的方框中的像素点的衬比值赋给中央点，方框右移一个像素点。如此循环，以此对所有区域进行同样的运算，最后获得各个区域的衬比值。计算空间衬比的流程示意图Lab of biomedical photonicshttp:/02 May 2024Page 31激光散斑时间衬比分析计算时间衬比的流程示意图如图所示，对这一系列图片空间上每一个像素都对应有一个光强变化的时间序列，对这一个时间序列进行时间衬比统计，则获得该点的时间衬比，类似于对空间上每一个像素点做类似处理。Lab of biomedical photonicshttp:/02 May 2024Page 32激光散斑空间衬比分析计算时空衬比的流程示意图基于时间和空间的衬比分析方法，衍生出多种将空间与时间统计相结合的衬比分析方法。总体思路如图所示，对NsNsNt个像素统计Lab of biomedical photonicshttp:/02 May 2024Page 33激光散斑衬比分析方法空间衬比K值图时间衬比K值图时空衬比K值图Lab of biomedical photonicshttp:/02 May 2024Page 34Instrumentationllaser light in the wavelength range of 600 nm to 900 nmla 10 bit or higher resolution CCD camera:exposure times may range from 1 ms to 20 ms;frame rates in the order of 10 to 30 frames per second.Lab of biomedical photonicshttp:/02 May 2024Page 35Laser SourceContinuous waveLower powerLinear polorized light632.8 He-Ne laser3 mW,SPL-HN250R,Hangzhou SPL Photonics,ChinaLab of biomedical photonicshttp:/02 May 2024Page 36Then the laser passes an expander and irradiates the imaging region with a diameter of 12 mm and the incident angle of 30-45。Light pathLab of biomedical photonicshttp:/02 May 2024Page 37la zoom stereo microscope(50486A,Navitar,USA)la monochrome 12 bit CCD camera(GS3-U3-51S5M-C,Point Grey,Canada)with 24482048 pixels,yielding an image of 1.57 mm 18.97 mm depending on the magnification with 0.58-7.0.The exposure time of the CCD was 15 ms.Images were acquired through the programming software at 20 Hz.Magnitude and CCDLab of biomedical photonicshttp:/02 May 2024Page 38LSCI system in our labLab of biomedical photonicshttp:/02 May 2024Page 39图左.7激光散斑测得的大脑血流变化图A、B、C、DE分别代表急性酒精注射前、注射后20分钟、40分钟、60分钟、80分钟时刻的大脑局部血流伪彩图，F为白光照射下拍摄的原始图片；图中使用红色矩形框标示出感兴趣区域。激光散斑成像血流图急性饮酒实验图右.激光散斑测得的ROI区域大脑血流变化CBF图Lab of biomedical photonicshttp:/02 May 2024Page 40激光散斑衬比成像的研究趋势成像参数的研究成像方式的研究成像方法的应用Lab of biomedical photonicshttp:/02 May 2024Page 41激光散斑衬比成像参数的研究 散斑大小的研究Dunn proposed Here,is the diameter of the speckle Airy disc,is the wavelength,is the magnification and the f-number is the ratio of focal length to aperture diameter.Kirkpatrick et al.showed that speckle sizes below twice the pixel size cause the speckle contrast to severely.Therefore,a speckle size of twice the pixel size is considered optimal.#Lab of biomedical photonicshttp:/02 May 2024Page 42曝光时间的研究Effect of camera exposure time(1)Speckle contrast images at six separate exposures exhibiting increased speckle visibility(e.g.,contrast)at lower exposures and highlighting varying flow range sensitivity with exposure selection.(2)The overall effect of exposure time on a set of normalized laser speckle contrast images.Smaller vessels become more visible as the exposure time increases,but simultaneously,the effect of increasing image noise becomes evident.Lab of biomedical photonicshttp:/02 May 2024Page 43激光散斑衬比成像的研究趋势成像参数的研究成像方式的研究成像方法的应用Lab of biomedical photonicshttp:/02 May 2024Page 44便携式激光散斑成像系统Lab of biomedical photonicshttp:/02 May 2024Page 45光纤内窥视激光散斑成像系统a:The fiber-based LSI probe is composed of a leached fiber bundle with a lens at one end.The fiber bundle directs light through a 4 objective to the camera sensor.b:A custom-built adjustable lens holder contains a 2 mm drum lens.The imaging fiber fits through a hole down the center of the metal and plastic pieces.The plastic end rotates to allow for fine focusing by adjusting the distance between the end of the fiber bundle and the drum lensc:The imaging fiber bundle(black)is placed 50 mm from the subject.The laser fiber(blue)transmits laser light into the mouth,to the lingual side of the tooth.d:The laser fiber(blue)is coupled with an SMA adapter to the retroreflector(black).This component contains two right-angle prisms(white)to redirect the light towards the lingual side of the tooth hence towards the imaging fiber bundle.Lab of biomedical photonicshttp:/02 May 2024Page 46多模式光学联合电生理记录系统Schematic representation of experimental setup and strategy for multimodal optical imaging.(a):Diagram of instruments used for detections of fluorescence signal,dual-wavelength OISs and blood velocity.Coupling of fluorescence imaging and dual-wavelength OISI was achieved with time-sharing CCD1 by alternating the center wavelength of LCTF.LSCI was accomplished by LD illumination and raw speckle images were continuously acquired by CCD2.Synchronization of the two CCD was achieved by a signal delivered from PC1.(b):Timing charts of fluorescence imaging and dual-wavelength OISI by CCD1.Lab of biomedical photonicshttp:/02 May 2024Page 47激光散斑衬比成像的研究趋势成像参数的研究成像方式的研究成像方法的应用与发展Lab of biomedical photonicshttp:/02 May 2024Page 48(A)Laser speckle contrast imaging(LSCI)estimated perfusion(left;from low perfusion in black to high perfusion in red),intensity(middle)and picture(right)on the forearm.Regions of interests(ROIs)were adjacent to the LDF probes(numbered 13)and within the SHP3 heating probe(4).(B)Flux pattern recorded with LSCI for the 4 ROIs during the five periods analyzed:baseline before post-occlusive hyperemia(PORH BL),PORH peak(PORH PK),baseline before LTH(LTH BL),LTH peak(LTH PK)and LTH plateau.PU:perfusion units.LDF 和LSCI 结合皮肤灌注研究 Lab of biomedical photonicshttp:/02 May 2024Page 49Sample images generated from a typical burn scar showing a hypertrophic scar surrounded by normal skin:(a)LSPI CCD camera photograph;(b)LSPI perfusion image;(c)Moor LDI total reflected light intensity map;(d)Moor LDI perfusion map.LSCI用于皮肤伤疤的研究Lab of biomedical photonicshttp:/02 May 2024Page 50LSI blood-flow index and percent-change maps of a rat retina.LSI was performed while the animal was breathing air or oxygen.Percent change maps are the differences between oxygen and air breathing.Lab of biomedical photonicshttp:/02 May 2024Page 51Cortical blood flow dynamics chronically captured before and after regional photo-thrombosis(outlined region)with periodic multiexposure speckle imaging in a cranial window implanted mouse.Photo-thrombotic parameters:20 mW of 532 nm wavelength laser,spot diameter of 600 m,15 minutes of irradiation with Rose Bengal administration(100 mg/kg,intraperitoneal).Image scale bar=500 m.ICT,inverse correlation time.光诱发血栓模型Lab of biomedical photonicshttp:/02 May 2024Page 52Photograph of human cortex captured by a surgical microscope and the corresponding speckle contrast image.The outlined region has reduced cortical blood flow from vascular cauterization.临床手术研究的脑血流激光散斑图 A primary concern has been assessing cortical vascular patency during the surgical procedures Lab of biomedical photonicshttp:/02 May 2024Page 53PTMR动静脉分割Lab of biomedical photonicshttp:/02 May 2024Page 54现有产品：Lab of biomedical photonicshttp:/http:/www.gene-and- of biomedical photonicshttp:/02 May 2024Page 56亚低温状态皮层扩散抑制模型Lab of biomedical photonicshttp:/02 May 2024Page 57总结总结总结总结激光散斑技术可以用于组织表皮层的毛细血管及其血流研究。最近几年，它被广泛应用于脑皮层血流的活体成像中，尤其是各种生理病理动物模型中，相较于激光多普勒技术，它具有更高的空间分辨率。但其流速的校准，深度的研究仍然是技术问题的难题，目前发展趋势是往小型化，便携式，内窥式，用于临床的研究中。