NIHPublicAccessAuthorManuscriptFPGA.Authormanuscript;availableinPMC2011September27.Publishedinfinaleditedformas:FPGA.2009February22;2009(7):93–102.doi:10.1145/1508128.1508143.FPGA-BasedFront-EndElectronicsforPositronEmissionTomographyMichaelHaselman1,DonDeWitt1,WendyMcDougald2,ThomasK.Lewellen2,RobertMiyaoka2,andScottHauck1MichaelHaselman:haselman@ee.washington.edu;DonDeWitt:dewitdq@ee.washington.edu;WendyMcDougald:wam2@u.washington.edu;ThomasK.Lewellen:tkldog@u.washington.edu;RobertMiyaoka:rmiyaoka@u.washington.edu;ScottHauck:hauck@ee.washington.eduNIH-PAAuthorManuscript1DepartmentofElectricalEngineering,UniversityofWashington,Seattle,WA2DepartmentofRadiology,UniversityofWashington,Seattle,WAAbstractModernFieldProgrammableGateArrays(FPGAs)arecapableofperformingcomplexdiscretesignalprocessingalgorithmswithclockratesabove100MHz.ThiscombinedwithFPGA’slowexpense,easeofuse,andselecteddedicatedhardwaremakethemanidealtechnologyforadataacquisitionsystemforpositronemissiontomography(PET)scanners.Ourlaboratoryisproducingahigh-resolution,small-animalPETscannerthatutilizesFPGAsasthecoreofthefront-endelectronics.Forthisnextgenerationscanner,functionsthataretypicallyperformedindedicatedcircuits,oroffline,arebeingmigratedtotheFPGA.Thiswillnotonlysimplifytheelectronics,butthefeaturesofmodernFPGAscanbeutilizestoaddsignificantsignalprocessingpowertoproducehigherresolutionimages.Inthispapertwosuchprocesses,sub-clockratepulsetimingandeventlocalization,willbediscussedindetail.WeshowthattimingperformedintheFPGAcanachievearesolutionthatissuitableforsmall-animalscanners,andwilloutperformtheanalogversiongivenalowenoughsamplingperiodfortheADC.WewillalsoshowthatthepositionofNIH-PAAuthorManuscripteventsinthescannercanbedeterminedinrealtimeusingastatisticalpositioningbasedalgorithm.KeywordsPET;FPGA;DigitalSignalProcessing;PulseTiming;EventLocalization1.IntroductionTheabilitytoproduceimagesoftheinsideofalivingorganismwithoutinvasivesurgeryhasbeenamajoradvancementinmedicineoverthelast100years.ImagingtechniquessuchasX-raycomputertomography(CT)andmagneticresonanceimaging(MRI)havegivendoctorsandscientiststheabilitytoviewhigh-resolutionimagesoftheanatomicalstructuresinsidethebody.Whilethishasledtoadvancementsindiseasediagnosisandtreatment,thereisalargesetofdiseasesthatonlymanifestaschangesinanatomicalstructureinthelatestagesofthedisease,orneveratall.Thishasgivenrisetoanotherbranchofmedicalimaging,calledNIH-PAAuthorManuscriptfunctionalimaging,whichisabletocapturecertainmetabolicactivitiesinsidealivingbody.Positronemissiontomography(PET)isthemostadvancedformofthisimagingmodality.Traditionally,thefront-endelectronicsofPETscannershaveconsistedofmanydiscretepartsthatperformthenecessarydataacquisitionandpulseprocessingfunctions.TherearecurrenteffortstoutilizeFPGAsforallormostofthedataacquisition[3,4]becausetheyHaselmanetal.Page2providethenecessaryspeedtoprocesstheincomingdatawithoutthecomplexityofanapplication-specificcircuit.TechnologyadvanceshavealsoyieldedFPGAswiththelogiccapacitytofitallofthenecessarytaskaswellasaddingtasksthatwherenotpossiblebefore.MostcurrentscannersusetheFPGAstocollectdataanddosomesimplefiltering.ThispaperdiscussesouruseofFPGAsinaPETscannerandhowweutilizethecapabilitiesofmodernFPGAstohelpproducehigherresolutionimages.2.PositronEmissionTomographyPETisamedicalimagingmodalitythatusesrad...