基于神经网络定位算法的高分辨率PET探测器研究-物理电子学专业论文.docx

摘要精度的影响。第六章详细介绍PET探测器实验平台的设计，包括电子学系统硬件和软件的设计，电子学系统的性能测试，探测器平台的组成和性能的初步测试。第七章详细描述由多通道光电倍增管H7546B和大块连续晶体LYSO组成的探测器性能，包括探测器的时间分辨率，能量分辨率和位置分辨率。第八章介绍了一个在FPGA中实现的，资源和速度有效折中的位置在线实时计算方案。第九章对本文的工作做了一个简要总结，并对目前和将来可进行的工作做了一个简要讨论。关键词：正电子断层扫描；多层感知器网络；连续晶体；LYSO；FPGAIIAbstractABSTRACTPositronemissiontomographyisanuclearimagingtechniquethatbasedonthedetectionofgammarays．Itisanoninvasivetechnologiesallowingtracinginvivometabolicfunctionoftheorganismatmolecularlevel．Inrecentyears，theinterestinsmallanimalpositronemissiontomography(PET)anddedicatedPET(1ikePEMandBrainPET)hasincreaseddramatically,stimulatingthedevelopmentofdetectorswithhighspatialresolution．Thesmalldimensionsoftheseanimalsandtheorgansofhumanimposestringentrequirementsonthehi．曲spatialresolutionandsensitivityofthosePETsystems．Currentdesignsbasedonmatricesofindividualcrystalpixelshaveachievedanintrinsicspatialresolutionbetterthan2mm．Butthedetectionefficiencyinthesepixelateddetectordesignsisreducedduetothedeadspaceintroducedbythereflectivematerialbetweenthecrystals．Additionally,thespatialresolutionmaybedeterioratedbyinter-crystalscatterandparallaxerrorsbecauseofdepthofinteraction(DOI)effects．Alternatively,detectorbasedonlargecontinuousscintillatorblocksresultsinahighersensitivitysincethereisnodeadspaceduetomaterialneededtoopticallyseparateindividualpixels．Thosedetectorshavetheadvantageofsimpledesign，lowercost，betterenergyandtimeresolution，compared谢ththepixilatedones．ThesizeofmonolithiccrystalsCallevenbechosensuchthattheycompletelycoverthephotodetectorsusedtoreadoutthescintillationlight，includingthepackaging．Theentrypointofadetected511keVphotononthesurfaceofthecrystal，insteadoftheinteractionpositionisdeterminedfromthedistributionofthescintillationlightusinganon-angerpositionalgorithm，suchasneuralnetwork，nearestneighborandstatisticsbasedpositioningalgorithm，etc．WearecurrentlydevelopingapracticalimplementationofprototypemonolithicscintillatorPETdetectormoduleswithneuralnetworkpositionalgorithm．Thisthesisgivesadetaileddescriptio