第九讲 CT技术和康普顿散射成象检测技术

CT(,100039)COMPUTEDTOMOGRAPHYANDCOMPTONSCATTERIMAGINGTECHNIQUEZhengShicai(XinliMachineryPlant,Beijing)1CT1.1CT,,,,,,,,,CT,,(Radon)19171950,1971EMICT,(CAT)70,,7080CT,80CT1993CCT,CT921CT:(1),,CTX,25MeV,3m(2)921ö%80keV420keV2MeVLpömm102520.5521020822.55208bitCT9995800.24.510416bit,0.1mm(3),CT,,,;,,;(4)CT2CADCT,1.2CT1.2.1(Radon)CT,,,,921,,,xy,32422920009NDTVol.22No.9Sep.2000©1995-2004TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.921,,ts,s(),txH,()tH,H,(x,y)(t,s),t=xcosH+ysinHs=-xsinH+ycosHg(x,y),PH(t),PH(t)=g(x,y)dxdyPH(t)=g(t,s)dsPH(t),0HPPH(t)Ht,t,H(x,y)()(t,H),(t,H),CT,L,(x,y)(t,s)L(x,y)=L(t,s)t(),sIH(t)=I0exp[-L(t,s)ds],lnI0IH(t)=LH(t,s)ds,PH(t),PH(t)=lnI0IH(t)=LH(t,s)dst,0HP,CT1.2.2(),,TX(T),X(T)=a0+(ancosnX0t+bnsinX0nt)X0=2PTan=2TX(T)cosnX0tõdtbn=2TX(T)sinnX0tõdt,,,CT(),,,,,,1.2.3CT,,,,CT,922,X1,X2,X3X4,,Y1,Y2,Y3Y4,X1+X2=Y1424:CT©1995-2004TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.922CTX1+X3=Y2X2+X3=Y3X2+X4=Y4,X1=12[Y1+Y2-Y3]X2=12[Y1-Y2+Y3]X3=12[Y2-Y1+Y3]X4=Y4-12[Y1-Y2+Y3]X1,X2,X3X4,CT,,CTCT,,,2CT21.3CT1.3.1CT,,,CT()CT,CT,CT,,=ûLf-LbûLb100%LbLfLbLf,Lf,H,h,höH,,ASTME1695-95CT,CT,,(ERF)(PSF)(MTF),(CDF)CTCDD(22)(923)CDD,,923CTCDD,A923CTCDD524:CT©1995-2004TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.,B,,(),1.3.2CT,CTCT,();CT,,,1.3.3CTCTCT,CT=LT-LWLW1000LTLWCT0,0,CT-10001.4CTCT,924CT,XCX,X,X924CT,,,C,,,C,,,C,CTXX,,X,CT,,(925)(a)(b)925CTCT,CdWO4,CaWO4,BGO,CsI(Tl),NaI(Tl)CT,,,,(),,(1),,,,CT:624:CT©1995-2004TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.(1)(2),(3),()(4),CT(),CT,CT1%1(5),CTCT45Lpömm;0.1%0.05%;30s30min;525Lm;20100Lm;10241024;;360cm,CT:(1)CT,,2563,0.3mm3(2)CTCT150kV,420kV,215MeV60Co,(3)CTCT,22.1,,,100%,:(1),,3mm,25mm,50mm(2),,,0.15mm;,6.7göcm3,1%,1.7göcm3;0.5mm2.2,hMX,,,E,Z,,,,,E=E1+A(1-cosH)EEA=EmC2mC$K$K=K-K=hmC(1-cosH)hh,mC,$K=2.426(1-cosH),,,,926927a,,,,(927b),,927,,724:CT©1995-2004TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.926A0.051MeVB0.2MeVC0.51MeVD2.04MeVE5.1MeV927Is=KI0wLFPFSIs=KI0wLFPFSFPTFSLLwKC=IS-ISIS=L-LL,L=0,C=1,100%,,,,,,,,,,2.3,,,,BGO(),,,:160kVö19mA;:22;:0.4mm0.4mm,0.4mm;:50mm100mm;:1.256.25min;:250500;:5mm,20mm,50mm:1999208210(405)10..,1992,11(4):1-611CastaingsM,HostenB.Theuseofelectrostatic,ultrasonic,air2coupledtransducerstogenerateandreceiveLambwavesinanisotropic,viscoelasticplates.Ultrasonics,1998,36(5):361-36512,..,1998,17(2):1-513LiuZhenqing,WeiMoan.Fuzzydetectionforultrasonicflawinspectionofhighlyscatteringmaterials.ChineseJournalofAcoustics,1997,16(4):332-33814LiuZQ,LuMD,WeiMA.Structuresnoisereductionofultrasonicsignalsusingartificialneuralnetworkadaptivefiltering.Ultrasonics,1997,35(4):325-328:1999212213824:CT©1995-2004TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.