Radiationdoseenhancementinskintherapywithnanoparticleaddition:AMonteCarlostudyonkilovoltagephotonandmegavoltageelectronbeams
WorldJournalofRadiology
頁(yè)數(shù): 9 2017-02-28
摘要: AIMToinvestigatedthedoseenhancementduetotheincorporationofnanoparticlesinskintherapyusingthekilovoltage(kV)photonandmegavoltage(MV)electronbeams.MonteCarlosimulationswereusedtopredictthedoseenhancementwhendifferenttypesandconcentrationsofnanoparticleswereaddedtoskintargetlayersofvaryingthickness.METHODSClinicalkVphotonbeams(105and220kVp)andMVelectronbeams(4and6MeV),producedbyaGulmayD3225orthovoltageunitandaVarian21EXlinearaccelerator,weresimulatedusingtheEGSnrcMonteCarlocode.Dosesatskintargetlayerswiththicknessesrangingfrom0.5to5mmforthephotonbeamsand0.5to10mmfortheelectronbeamsweredetermined.TheskintargetlayerwasaddedwiththeAu,Pt,I,AgandFe2O3nanoparticleswithconcentrationsrangingfrom3to40mg/mL.Thedoseenhancementratio(DER),definedasthedoseatthetargetlayerwithnanoparticleadditiondividedbythedoseatthelayerwithoutnanoparticleaddition,wascalculatedforeachnanoparticletype,nanoparticleconcentrationandtargetlayerthickness.RESULTSItwasfoundthatamongallnanoparticles,AuhadthehighestDER(5.2-6.3)whenirradiatedwithkVphotonbeams.DependenceoftheDERonthetargetlayerthicknesswasnotsignificantforthe220kVpphotonbeambutitwasfor105kVpbeamforAunanoparticleconcentrationshigherthan18mg/mL.Forothernanoparticles,theDERwasdependentontheatomicnumberofthenanoparticleandenergyspectrumofthephotonbeams.AllnanoparticlesshowedanincreaseofDERwithnanoparticleconcentrationduringthephotonbeamirradiationsregardlessofthickness.Forelectronbeams,theAunanoparticleswerefoundtohavethehighestDER(1.01-1.08)whenthebeamenergywasequalto4MeV,butthiswasdrasticallylowerthantheDERvaluesfoundusingphotonbeams.TheDERwasalsofoundaffectedbythedepthofmaximumdoseoftheelectronbeamandtargetthickness.Forothernanoparticleswithloweratomicnumber,DERsintherangeof0.99-1.02werefoundusingthe4and6MeVelectronbeams.CONCLUSIONInnanoparticle-enhancedskintherapy,Aunanoparticleadditioncanachievethehighestdoseenhancementwith105kVpphotonbeams.Electronbeams,whilepopularforskintherapy,didnotproduceashighdoseenhancementsaskVphotonbeams.Additionally,theDERisdependentonnanoparticletype,nanoparticleconcentration,skintargetthicknessandenergiesofthephotonandelectronbeams. (共9頁(yè))