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1、JSouthMedUniv,2016,36(7):969-973doi10.3969/j.issn.1673-4254.2016.07.17·969·基础研究ࠎႿᄎҀӊ෪ۋᆩ4D-CBCTႪᇉᇗࡹ12222212杨轩,张华,何基,曾栋,张忻宇,边兆英,张敬,马建华12天津医科大学总医院医学影像科,天津300070;南方医科大学广东省医学图像处理重点实验室,广东广州510515摘要:受硬件限制,4D-CBCT成像中单个呼吸相位对应投影数目过少,而相应的常规解析算法重建图像中充斥着大量噪声和伪影。为解决此问题,鉴于当前呼吸相位图像可以通过其它呼吸相位图像运动补偿获取,本文中我们提出一种利
2、用多相位投影数据重建4D-CBCT的策略。本文中我们构建了包含基于多相位投影数据的保真项和基于压缩感知理论的全变分正则化的代价函数。对于投影数据保真项的设计,不再局限于当前相位投影数据,而是利用多个相位投影数据通过变形的成像模型联合构建。对于复杂代价函数的优化,我们利用GPBL(Gradient-Projection-Barzilai-Linesearch,GPBL)算法来实现。物理体模及临床数据实验结果表明,相对于解析算法及代数迭代全变分约束算法,新方法在噪声和伪影的抑制方面有上佳表现,引入不同相位图像间的关联信息并未引入新的伪影和运动模糊。关键词:四维锥形束CT;运动补偿;压缩感知M
3、otion-compensatedcompressedsensingfour-dimensionalcone-beamCTreconstructionYANGXuan1,ZHANGHua2,HEJi2,ZENGDong2,ZHANGXinyu2,BIANZhaoying2,ZHANGJing1,MAJianhua21DepartmentofMedicalImaging,GeneralHospitalAffiliatedtoTianjinMedicalUniversity,Tianjin300070,China;GuangdongProvincialKeyLaboratoryofMedic
4、alImageProcessing2,SouthernMedicalUniversity,Guangzhou510515,ChinaAbstract:Restrictionbyhardwarecausedtheverylowprojectionnumberatasinglephasefor4-dimensionalconebeam(4D-CBCT)CTimaging,andreconstructionusingconventionalreconstructionalgorithmsisthusconstrainedbyseriousstreakartifactsandnoises.Toa
5、ddressthisproblem,weproposeanapproachtoreconstructing4D-CBCTimageswithmulti-phaseprojectionsbasedontheassumptionthattheimageatonephasecanbeviewedasthemotion-compensatedimageatanotherphase.Specifically,weformulatedacostfunctionusingmulti-phaseprojectionstoconstructthefidelitytermandtheTVregulariza
6、tionmethod.Forfidelitytermconstruction,theprojectiondataofthecurrentphaseandthoseatotherphaseswerejointlyusedbyreformulatingtheimagingmodel.TheGradient-Projection-Barzilai-Linesearch(GPBL)methodwasusedtooptimizethecomplexcostfunction.Physicalphantomandpatientdataresultsshowedthattheproposedapproa
7、chcouldeffectivelyreducethenoiseandartifacts,andtheintroductionofadditionaltemporalcorrelationdidnotintroducenewartifactsormotionblur.Keywords:4-dimensionalconebeamcomputedtomography;motioncompensation;compressedsensin