学术交流英语PPT讲稿-图文

30sGoodafternoon,everyone.ThetitleofthepaperisVisibleMicrospectroscopyforDiagnosisofGastricPrecancer.ItsauthorisLiuYongfromDepartmentofPhysics,ZhaoqingUniversity.It’spresentedbyLiMengfanfromCAS,HefeiInstitutesofPhysicalScience.Youcanknowmoreaboutcancerandthenewmethodtodiagnosegastricprecancerafterreadingthispaper.58sCancerisverycommonamonghumanbeings.Itismostlyrelatedtothehabitofthepatients,thejob,theenvironment,thedrinkingwaterandthesoilmatters,too.Ifapersonisaffectedbycertainbacteria,hemayalsogetgastriccancer.Badhabitslikesmoking,drinking,mentaltension,eatingimproperlyandlivingirregularlyincreasethepossibilityofhavingcancer.Beforespecifictreatment,thedoctorshouldmakesurewhetherthepatienthascancerandwherethefocusis.Themethodusedtodiagnosecancerandlocatethecancerousareaisveryimportant.42sBeforewedesignamethodtodiagnosecancer,weshouldknowmoreaboutcancerlikewhereitstartsandwhatitcauses.Firstly,about90%ofthehuman’scancerstartfromtheepitheliallayerofskin,internalorgansandtubularorgansinthebody.Secondly,cancerusuallyaccompaniedbythechangesoforganizationstructureinthecelllevel.So,thechangeswhichappearinthestructureoforganizationandchemicalcompositionprovidesimportantevidencefordiagnosisofprecancer.42sNormalmethodtodiagnosegastricprecancerisReflectancespectroscopy.It’sveryprospectiveinearlydiagnosisofcancerandiscommonlyusedtheseyears.Oneofthemostcommontechnologyisdiffusereflectancevisiblespectroscopy,itcanacquiretheapproximateinformationofthetargettissue.Thismethodislowcost,fastandnon-invasive,itprovidesimportantmeansfordiagnosisofmalignantdamageoforganizationofhumanorgans.However,therearealsosomedisadvantagesofthismethodwhichneedtobeimproved.55sThisisthesystemofdiffusereflectancespectroscopy,thelightbeamemittedfromthetungstenhalogenlampisguidedintotheintegralballbythesourcefiber.Thelightcomeoutoftheintegralballirradiatethestandardboard,thereflectedlightofthestandardboardistreatedasthebackground.Thentaketargettissuesubstituteforthestandardboard,andscanthereflectedlightofit.Thereflectedlightspectraofthegastrictissuemucosallayerandthesubmucosalayerisguidedintothespectrometerbythecollectorfiber.ThespectrometerandthecomputerisconnectedbyUSB,spectrumcanbeprocessedusingcomputer.36sFirstofall,onlyaveragevisiblespectrumofthetargettissuecanbeacquired,itmeansthatthedocterscannotmakeoutthelocationofthecanceroustissueprecisely.What’smore,thedeviceiseasytobeaffectedbychangesofopticalpathlengthinducedbydifferentset-upofproberandthevariationofhemoglobinconcentrationduetothepressurebetweenproberandtissue.50sToavoidtheproblemsofthecommonlyusedtechniques,diffusereflectancevisiblespectroscopy,scientistsdoalotofresearchestofindoutanewwaytodiagnoseprecancer.ThenewmethodisVisibleMicrospectroscopy.Thevisiblemicrospectroscopicmeasurementdeviceisaccomplishedonthebasisoffiberconfocalmicroscope,its3-dimagingprincipledevotetotheopticaltomographyabilityofthesystem.Thevisiblemicrospectrumofcancerousandnormaltissuecanbeanalysedandcontrasted,soit’smoreusefulthanthenormalmethod.45sThisisthestructureofthevisiblemicrospectroscopydevice.Thefibercouplercanseparatethelightingbeamsfromthesignalbeam.Thetwolenscanfocusthelightonthetissue,The3-Delectroniccontrolledplatformmovealongthedirectionofopticaxis,sothatthedevicecanacquirethevisiblemicrospectroscopysignalofthesampleindifferentdepth,preciselylocatetheboundaryofthecanceroustissue.Thesignalmeasuredfromdifferentpositioncanbestoredinthecomputerafteranalysedbythespectrometer.31sThisisthespectrumchartofthenormaltissueandcanceroustissue,theyareanalyzedbythespectrometerbeforebeingtransmittedtothecomputer.Theupperchartisthevisiblespectrumofnormaltissue,itisregular.Contrastingtothis,inthenetherchart,thespectrumofthecancerousareashowsthatthestrengthofreflectedlightgrowsasthewavelengthgrows.49sIncomparisonwiththenormalmethod,therearealotofadvantagesofthenewmethod.Firstly,thestructureofvisiblemicrospectroscopydeviceisverysimple.Themainpartsconsistofsource,fibercoupler,3-Delectroniccontrolledplatform,spectrometerandthecomputer.Secondly,the3-Dspacemicrospectrumcanbeacquired,whichcanhelpthedoctorsefficientlymakeoutwhetherthegastrictissueiscancerous.What’smore,theopticaltomographyabilityenabledthedevicetopreciselylocatetheedgeofthecancerousarea.32si.Inconclusion,themaingoalofthisresearchistofindanewwaytodiagnosethegastricprecancer.ii.Thespectrumofthenormalandcancerousgastrictissueswhichcanbemeasuredbyvisiblemicrospectroscopyincelllevelisthecentralidea.iii.Thisnewmethodcanobtainthecelllevelinformation,andisnotaffectedbychangesofopticalpathlengthandhemoglobinconcentration.50si.Thedeviceisverysimple,soitcanhaveasmallsize,whichcanreducethesufferingsofpatients.Itcanefficientlymakeoutwhetherthetissueiscanceration.ii.Besides,the3-Dspacemicrospectrumandopticaltomographyabilitycanmakethedeviceaccuratelydistinguishthecanceroustumorareafromthenormaltissueincelllevel,thustheboundaryofthecanceroustissuecanbeascertainedaccurately.iii.Theresultoftheresearchshowsthatthisdevicemaybeusedtonon-invasivelydiagnosisofearlygastriccancer.2