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292Vol.29No.220093NuclearElectronics&DetectionTechnologyMar.2009MonteCarlo陈少文1,2,王学涛1,3,陈立新4,曹午飞1,唐强1,刘小伟1(1.,510275;2.,523808;3.,510120;4.,510060):EGSnrc/BEAMnrcVarian600C,,,:;MonteCarlo;BEAMnrc:R730.5:A:025820934(2009)0220328204:2008209211:(1067517510505033):(1967-),,,,,,,,20%~30%[1],,[2],,,IMRTIGRT,,MonteCarlo,MonteCarlo,[327]Varian600C,,Varian600CMonteCarlo,111,EGSnrc/BEAMnrc[8,9]BEAMn23282rc,,,Be,VarianAE=ECUT=0.70MeV,AP=PCUT=0.01MeV,ESAVE=2.0MeV,DBS(DirectionalBremsstrahlungSplitting),NBRSPL=1000,FS=30cm50@50@50cm3,79@79@151,SSD=100cm2,,:,,DOSXYZnrc;,,,,1%1mm[326],(108),1%()Varian600C,Scanditronix/Wellhofer,(iba:cc132s27715)(DEB01022710)2211310@10cm2(PDD)37.0MeVPDD5.4MeV5.8MeVPDD,PDD,5.4MeV5.8MeVPDD,PDD5.8MeVPDD,1%,310@10cm2440@40cm2212(OAR)432940@40cm2,5.8MeV,FWHM=0.1cm,5cm10cm20cm30cm(,10cm20cm30cmOAR0.80.60.4)10cmOAR,1%,1mm,xy,2135,55.8MeVFWHM=0.1cm10cm,,,,5,(1%),,(20@20cm2),,3MonteCarlo,,,[10,11],MonteCarloMonteCarlo,,[3],,[4],MonteCarlo,[327],,(PDD)(OAR),,,,:[1],.[J].,1997,17(5):3522354.[2],.[M].:,1999.[3]Sheikh2BagheriD,RogersDWO.SensitivityofmegavoltagephotonbeamMonteCarlosimulationstoelectronbeamandotherparameters[J].Med.Phys.2002,29(3):3792390.[4]KeallPJ,etal.DeterminingtheincidentelectronfluenceforMonteCarlo2basedphotontreatmentplanningusingastandardmeasureddataset[J].Med.Phys.2003,30:5742582.[5]TzedakisA,etal.InfluenceofinitialelectronbeamparametersonMonteCarlocalculatedab2sorbeddosedistributionsforradiotherapyphotonbeams[J].Med.Phys.2004,31:9072913.[6]AljarrahK,etal.DeterminationoftheInitialBeamParametersinMonteCarloLinacSimulation[J].Med.Phys.2006,33:8502858.[7],.[C]...2008:5522554.[8]KawrakowI,RogersDWO.TheEGSnrcCode330System[M].PIRS2701,2000.[9]RogersDWO,etal.BEAM:aMonteCarlocodetosimulateradiotherapytreatmentunits[J].Med.Phys.1995,22:5032525.[10]WaltersBRB,etal.HistorybyhistorystatisticalestimatorsintheBEAMcodesystem[J].Med.Phys.2002,29(12):274522752.[11]KawrakowI,WaltersBRB.EfficientphotonbeamdosecalculationsusingDOSXYZnrcwithBEAMnrc[J].Med.Phys.2006,33(8):304623056.MonteCarloSimulationforMedicalLinacCHENShao2wen1,2,WANGXue2tao1,3,CHENLi2xin4,CAOWu2fei1,TANGQiang1,LIUXiao2wei1(1.SchoolofPhysicsScienceandEngineering,SunYat2SenUniversity,Guangzhou510275;2.ElectronEngineeringDepartment,DongguanUniversityoftechnology,Dongguan523808;3.GuangdongProvinceHospitalofTCM,Guangzhou510120;4.CancerCenterofSunYat2SenUniversity,Guangzhou,510060)Abstract:TheMonteCarlocodeEGSnrc/BEAMnrcwasusedtosimulatetheVarian600CmedicalLinac.TheparametersoftheincidenceelectronsbeamforthisLinachadbeenderivedbycomparingthedosedis2tributionbetweentheresultsfromMonteCarlosimulationandthedatafrommeasurement.Theinfluenceoftheincidenceelectronstothepercentdepthdosage(PDD)andtheabsorbeddoseoffaxisratio(OAR),andtheinfluenceofthefieldsizetothepercentdepthdose,werediscussed.Thesimulationresultsareconsistentwiththemeasurementresults,andcanbeusedforthefurtherresearch.Keywords:Linac,MonteCarlosimulation,BEAMnrc(257,Continuedfrompage257)HighVoltageMOSFETnsGradeEdgePulseGeneratorStudyWANGXin(InstituteofElectronEngineering,ChinaAcademyofEngineeringphysics,Mianyang621900,China)Abstract:Inthispaper,apulsegeneratorwithnsgradefastriseandfalltimebaseonhighvoltageMOS2FETispresented.Wemainlyanalyzeandexperimentthemethodofformingfastpulseedge,theoverdrivingtechnologyofMOSFETandthetechnologyofseriesMOSFETs,toimprovetheoutputcharacter2isticsofpulsegenerator.Inexperiment,toswitchofhighvoltageMOSFETusehighvoltageavalanchetransistorandpulsetransformeroverspikedrivingtechniques,thepulseamplitudeisover4kV,pulseedgeisabout5ns.Keywords:HighvoltageMOSFET,nsgradepulseedge,Overspikedriving,Doublefastedge331