生物医学光子学与激光散斑成像科学探究

LaserSpeckleContrastImagingTheory,InstrumentationandApplicationsDepartmentofBiomedicalEngineeringLabofBiomedicalPhotonicsBiomedicalOpticsTopic10May2024Page2IntroductiontoBiomedicalOpticsDiffuseOpticalTomography(DOT)

PhotoacousticImaging(PAI)Multi-spectralOpticalIntrinsicSignalImaging

MolecularImagingUltrafastPhotography

HighResolutionAltasofMouseBrainLaserSpeckleContrastImaging

Theory

Instrumentation

ApplicationsOuline10May2024Page3GeneralopticstheoryTherapeuticapplicationsoflightDiagnosticopticalmethodsMedicalopticalimagingistheuseoflightasaninvestigationalimagingtechniqueformedicalapplications.BiomedicalOptics10May2024Page4DiffuseOpticalTomography(DOT)NatPhotonics.2014June;8(6):10May2024Page5DiffuseOpticalTomography(DOT)10May2024Page6PhotoacousticImaging(PAI)10May2024Page7PhotoacousticImaging(PAI)10May2024Page8PhotoacousticImaging(PAI)10May2024Page9Multi-spectralOpticalIntrinsicSignalImaging10May2024Page10Multi-spectralOpticalIntrinsicSignalImagingSimultaneousdetectionofhemodynamics,mitochondrialmetabolismandlightscatteringchangesduringcorticalspreadingdepressioninratsbasedonmulti-sNeuroImageVolume76,1August2013,Pages70–8010May2024Page11MolecularimagingMarinaVBacker,

NATUREMEDICINE2007,1310May2024Page12MolecularimagingW.T.Li,BIOMEDICALOPTICSEXPRESS,2014,2679L.M.Nie,ACSNano,201410May2024Page13MolecularimagingInvivophotoacousticimagingofbraininjuryandrehabilitationbyNIRdyelabeledmesenchymalstemcellswithenhancedbrainbarrierpermeability

WeitaoLi†,#,HongkeWang†,‡,#,JingLv‡,#,RongheChen‡,YuLiu‡,YaPeng‡,andLimingNie‡,*10May2024Page14UltrafastPhotographyLGaoetal.Nature516,74-77(2014)10May2024Page15UltrafastPhotographyhighspeeddigitalimagesequence10May2024Page16HighResolutionAltasofMouseBrain10May2024Page17HighResolutionAltasofMouseBrainLiA,2010,Science,330(6009)10May2024Page18LaserSpeckleContrastImaging

Theory

Instrumentation

ApplicationsOuline10May2024Page19Whatislaserspecklecontrastimaging?J.Senarathna,IEEEReviewsinBiomedicalEngineering,6,201310May2024Page20Whencoherentlightscattersfromarandommedium,thescatteredlightproducesarandominterferencepatterncalledspeckle.SpeckleDefinition*D.A.Boas,JournalofBiomedicalOptics,2010,15(1)#D.Briers,JournalofBiomedicalOptics,2013,18(6)10May2024Page21SpeckleJ.Senarathna,IEEEREVIEWSINBIOMEDICALENGINEERING,6,201310May2024Page22Thetheoreticalbasisforanalyzingspeckleintensityfluctuationsdatesbacktothelate1960swiththedevelopmentofdynamiclightscattering.History-1960R.Pecora,AnnualReviewofBiophysicsandBioengineering,197210May2024Page23Therewasextensiveactivityinthe1970srigorouslyrelatingspeckletemporaldynamicstovariousformsofparticledynamicsindilutesingle-scatteringsuspensions.History-1970InvivoevaluationofmicrocirculationbycoherentlightscatteringNature254,56-58(06March1975)10May2024Page24Asolutionwaspresentedinthe1980susingacameratoobtainaquicksnapshotimageofatime-integratedspecklepattern,History-1980A.Fercher,OpticsCommunications37(5),198110May2024Page25Thismethod,laserspecklecontrastimaging(LSCI),wasadvancedinthe1990sforimagingbloodflowintheretinaandskinwiththeavailabilityoffasterdigitalacquisitionandprocessingtechnologies.History-199010May2024Page26Thespeckleimageof2-DmapsofbloodflowcanbeobtainedwithveryhighspatialandtemporalresolutionbyusingaCCDcameraandquantifyingthespatialblurringofthespecklepattern.Toquantifytheblurringofthespeckles,thespecklecontrast,definedastheratioofthestandarddeviationtothemeanintensity,iscomputedas,TheoreticalBackgroundNotethatweuseδs

torefertothespatialstandarddeviationofthespeckleintensity,Kisthespatialspecklecontrast,and<I>istheaverageintensityofspeckleimage.10May2024Page27激光散斑衬比成像基本原理

10May2024Page28ThisgivesaspecklecontrastTheoreticalBackground

10May2024Page29ModulateofLSCI(a)SpatialSpeckleContrast(b)TemporalSpeckleContrast(c)SpatialversusTemporalSpeckleContrast10May2024Page30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Ns×Ns

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10May2024Page31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。10May2024Page32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Ns×Ns×Nt个像素统计10May2024Page33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10May2024Page34Instrumentationlaserlightinthewavelengthrangeof600nmto900nma10bitorhigherresolutionCCDcamera:exposuretimesmayrangefrom~1msto~20ms;frameratesintheorderof10to30framespersecond.10May2024Page35LaserSourceContinuouswaveLowerpowerLinearpolorizedlight632.8He-Nelaser3mW,SPL-HN250R,HangzhouSPLPhotonics,China10May2024Page36Thenthelaserpassesanexpanderandirradiatestheimagingregionwithadiameterof~12mmandtheincidentangleof30°-45°。Lightpath10May2024Page37azoomstereomicroscope(50486A,Navitar,USA)amonochrome12bitCCDcamera(GS3-U3-51S5M-C,PointGrey,Canada)with2448×2048pixels,yieldinganimageof1.57mm×18.97mmdependingonthemagnificationwith0.58×-7.0×.TheexposuretimeoftheCCDwas15ms.Imageswereacquiredthroughtheprogrammingsoftwareat20Hz.MagnitudeandCCD10May2024Page38LSCIsysteminourlab10May2024Page39图左.7激光散斑测得的大脑血流变化图A、B、C、D、E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10May2024Page40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10May2024Page41激光散斑衬比成像参数的研究散斑大小的研究Dunnproposed

Here,isthediameterofthespeckleAirydisc,isthewavelength,isthemagnificationandthef-numberistheratiooffocallengthtoaperturediameter.Kirkpatricketal.showedthatspecklesizesbelowtwicethepixelsizecausethespecklecontrasttoseverely.Therefore,aspecklesizeoftwicethepixelsizeisconsideredoptimal.

10May2024Page42曝光时间的研究EffectofcameraexposuretimeSpecklecontrastimagesatsixseparateexposuresexhibitingincreasedspecklevisibility(e.g.,contrast)atlowerexposuresandhighlightingvaryingflowrangesensitivitywithexposureselection.Theoveralleffectofexposuretimeonasetofnormalizedlaserspecklecontrastimages.Smallervesselsbecomemorevisibleastheexposuretimeincreases,butsimultaneously,theeffectofincreasingimagenoisebecomesevident.10May2024Page43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10May2024Page44便携式激光散斑成像系统10May2024Page45光纤内窥视激光散斑成像系统a:Thefiber-basedLSIprobeiscomposedofaleachedfiberbundlewithalensatoneend.Thefiberbundledirectslightthrougha4×objectivetothecamerasensor.b:Acustom-builtadjustablelensholdercontainsa2mmdrumlens.Theimagingfiberfitsthroughaholedownthecenterofthemetalandplasticpieces.Theplasticendrotatestoallowforfinefocusingbyadjustingthedistancebetweentheendofthefiberbundleandthedrumlens.c:Theimagingfiberbundle(black)isplaced~50mmfromthesubject.Thelaserfiber(blue)transmitslaserlightintothemouth,tothelingualsideofthetooth.d:Thelaserfiber(blue)iscoupledwithanSMAadaptertotheretroreflector(black).Thiscomponentcontainstworight-angleprisms(white)toredirectthelighttowardsthelingualsideofthetoothhencetowardstheimagingfiberbundle.10May2024Page46多模式光学联合电生理记录系统Schematicrepresentationofexperimentalsetupandstrategyformultimodalopticalimaging.(a):Diagramofinstrumentsusedfordetectionsoffluorescencesignal,dual-wavelengthOISsandbloodvelocity.Couplingoffluorescenceimaginganddual-wavelengthOISIwasachievedwithtime-sharingCCD1byalternatingthecenterwavelengthofLCTF.LSCIwasaccomplishedbyLDilluminationandrawspeckleimageswerecontinuouslyacquiredbyCCD2.SynchronizationofthetwoCCDwasachievedbyasignaldeliveredfromPC1.(b):Timingchartsoffluorescenceimaginganddual-wavelengthOISIbyCCD1.10May2024Page47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10May2024Page48(A)Laserspecklecontrastimaging(LSCI)estimatedperfusion(left;fromlowperfusioninblacktohighperfusioninred),intensity(middle)andpicture(right)ontheforearm.Regionsofinterests(ROIs)wereadjacenttotheLDFprobes(numbered1–3)andwithintheSHP3heatingprobe(4).(B)FluxpatternrecordedwithLSCIforthe4ROIsduringthefiveperiodsanalyzed:baselinebeforepost-occlusivehyperemia(PORHBL),PORHpeak(PORHPK),baselinebeforeLTH(LTHBL),LTHpeak(LTHPK)andLTHplateau.PU:perfusionunits.LDF和LSCI结合皮肤灌注研究

10May2024Page49Sampleimagesgeneratedfromatypicalburnscarshowingahypertrophicscarsurroundedbynormalskin:(a)LSPICCDcameraphotograph;(b)LSPIperfusionimage;(c)MoorLDItotalreflectedlightintensitymap;(d)MoorLDIperfusionmap.LSCI用于皮肤伤疤的研究10May2024Page50LSIblood-flowindexandpercent-changemapsofaratretina.LSIwasperformedwhiletheanimalwasbreathingairoroxygen.Percentchangemapsarethedifferencesbe