放射治疗剂量学1课件

TheDosimetryofRadiationTherapyWangPengcheng2013BrifeIntroductionofRadiationTherapyandradiationdosimetryWangPengcheng2013ChemotherapySurgeryRadiationtherapyOthersRadiationTherapy：theMythsFormanylay-people,thewordradiationconjuresahostofmythsandmisconceptions.RadiationTherapy：theMythsRadiationTherapy：theMythsRadiationTherapy:MythsThetherapyisbelievedtoburnrecipients.Thetherapyisbelievedtomakethemradioactive(onlytruewithtemporaryinternalimplants).Oftenviewedaspainful.Oftenviewedasalastresort.RadiationTherapyIphylacticallytopreventleukemicinfiltrationtothebrainorspinalcord.Palliativeirradiationisfrequentlyusedtorelievesymptomsofmetastaticdisease,especiallywhenithasspreadtobrain,bone,orsofttissue.一、DefinitionofRadiationTherapy

Definition：Thephysicaltreatmenttechniquetokillthecancercellsortocontrolthegrowthoftumorbyirratiatingthetumorortissueinvasivedwithdefiniteddoseslocally

Beamavailableallbeam:xγπβαp…RadiationTherapyItisestimatedthatmorethan70%patientswithcancerwillreceiveradiation,eitherasaprimary,adjunctive,orpalliativeinterventionRadiationTherapyCancertreatmentmodalityusedtocure,control,orpalliatemalignantdisease.Bothinternalandexternalmeansofradiationtherapyareavailableforlocaldelivery.Radiationcanbeusedasatreatmentforsolidtumorsorcombinedwithothertreatmentmodalities(chemotherapyorsurgery).GoalsofRadiationTherapyCureToeradicatethediseaseControlControlthegrowthandthespreadofthecancerProphylaxisTocontrolmicroscopicdiseasePalliationToreducecomplicationsorsymptomsofthecancer.Maybeusedtocontrolpain.二、DevelopmentofRadiationTherapy1.developmentofradiationandequipmentsinRTIn1895x-raywasdiscovered.In1896,HenriBecquereldiscoveredthaturaniumsaltsemittedrayssimilartox-raysintheirpenetratingpower.

安东尼·亨利·贝克勒尔（AntoineHenriBecquerel，1852—1908年），法国物理学家。1896年3月，贝克勒尔发现，与双氧铀硫酸钾盐放在一起但包在黑纸中的感光底板被感光了。他推测这可能是因为铀盐发出了某种未知的辐射。从而确认了天然放射性的发现。

二、DevelopmentofRadiationTherapy后来，居里夫妇将其称为“放射性”。现在，我们称其为天然放射性。尽管贝克勒尔当时错误地认为它是某种特殊形式的荧光，但天然放射性的发现仍不愧是划时代的事件，它打开了微观世界的大门，为原子核物理学和粒子物理学的诞生和发展奠定了实验基础。ThisphenomenonwasstudiedbyPierreandMarieCurieandwaslaternamedradioactivitybythem.In1903,theCuriessharedwithHenriBecquereltheNobelprizeinphysicsfortheirinvestigationofuraniumandradioactivematerial.DevelopmentofRadiationTherapy关于curie介绍DevelopmentofRadiationTherapy1902，thetreatmentofskincancerusingradiationwasreported1920,orthovoltagetherapymachineinvented.ThefirstCobalt60machinewasproducedinCanada.1958,thefirstelectronacceleratorwasbuiltinBritain1968,themodernlinearacceleratorwasbuiltinUSAbyVarianbrothers1990’s,moderntime,3DRTduetothecomputertechnique.DevelopmentofRadiationTherapy2.developmentofradiobiologyTheprimaryunderstandofradiobiologywerefromtheinjureandthediseaseslike

leukaemia.

1950,celltechniquedeveloped.Cellcyclerevealed.1960,radiobiologyinmolecularlevel:targetthesis.DevelopmentofRadiationTherapyRadiationCellularEffectsApproximately20%isadirecteffect.IonizingradiationcausesbreakageamongthestrandsoftheDNAhelix,causingcelllysis,whichleadstocelldeath.WorksontheDNAofcancer&normalcells.Approximately80%isanindirecteffect.Ionizingcanalsoionizebodyfluids,especiallywaterinthecell,leadingtotheformationoffreeradicals,whichcauseirreversibledamagetotheDNAbybreakingthestrands.Thiscausescelllysisandcelldeath.RadiationcellularEffectsCellulardeathmayoccurimmediatelyifDNArepairdoesnotoccur,oratthetimeofcellulardivisionwhenthedamagedcellattemptsmitosis（有丝分裂）anddies.Finally,atumorcellmaybecomesterilebytheeffectsofradiationanddieanaturaldeathwithouttheabilitytoproduceprogeny(offspring).CellularFactorsInfluencingResponsetoRadiationOxygenationTumorsthatarewelloxygenatedaremoresensitivetoradiation.Radiationtherapymightbeenhancedifoxygenconcentrations,hyperoxygenation,totumorscouldbeincreased.CellularFactorsInfluencingResponsetoRadiationThereforethemostsensitivecellstoradiationarerapidlydividing,welloxygenated,morevascularcells.RadiosensitivityAradiosensitivetumorisonethatcanbedestroyedbyadoseofradiationthatstillallowsfornormalcellregenerationinthenormaltissue.Thosetissuesthatareslowergrowingoratrestarerelativelyradioresistant.Radiosensitivity3.RTdevelopmentinChina97-98,450hospitalshaveRT,about10000,radiationoncologists,technician,physicists

1998,about500unitsacceleratorsand500cobalt60and400afterloadsystemservedinhospitals.1999,about30rknifesand60x-knifeNow:wecan’timaginehowmanyRTequipmentsservedindifferentclinicunit.DevelopmentofRadiationTherapyDevelopmentofRadiationTherapyDevelopmentofRadiationTherapyDevelopmentofRadiationTherapyDevelopmentofRadiationTherapyDevelopmentofRadiationTherapyQuestion：HowmanypeopleofyouapplyforMedicalPhysicsasyourfirstchoice？DevelopmentofRadiationTherapyDevelopmentofRadiationTherapy表1肿瘤治疗五年生存率的变化年代20世纪初30年代60年代90年代五年生存率5%15%30%45%表2三大治疗手段对肿瘤治愈率的相对贡献治疗手段手术治疗放射治疗化学治疗相对贡献22%（48.9%）18%（40%）5%（11.1%）

三、ThemethologyandequipmentsforRadiationTherapy1.externalradiationtherapyIftheexternalradiationtherapyisused,oneofseveralmethodsofdeliverymaybechosen,dependingonthedepthofthetumortoberadiated.Thehighertheenergythedeeperthepenetratingintothebody.MachinesUsed:KilovoltageTherapyDevices(SuperficialradiationandOrthovoltage)deliverthemaximumradiationdosetosuperficiallesionssuchaslesionsoftheskinandbreast.Gammaraysources(Cobalt-60units)delivertheradiationdosetodeeperbodystructuresandsparetheskinfrompossibleadverseeffects.

三、ThemethologyandequipmentsforRadiationTherapyMegavoltageTherapy(LinearacceleratorsandBetatronMachines)delivertheirdosagetodeeperstructureswithoutharmingtheskinandalsocreatelessscatteringofradiationwithinthebodytissues.Thisishighenergyx-rays.Particlebeamtherapy(Cyclotrons)Thisisusedfortreatinghypoxic,radioresistanttumorswithneutronbeamtherapy.

三、ThemethologyandequipmentsforRadiationTherapy

三、ThemethologyandequipmentsforRadiationTherapy2.BrackytherapyContinuouslowdoseradiationfromimplants.Thebenefitsoflocalirradiationare:Ahighdosecanbegiveninarelativelyfewnumberofdays.Allowsahighdosetobegiveninthetumortissuewhilestayingwithinnormaltissuetolerancefortherestofthebody.

三、ThemethologyandequipmentsforRadiationTherapy

三、ThemethologyandequipmentsforRadiationTherapy3.StereotacticradiotherapyWhatisStereotacticRadiosurgery?StereotacticLocalizationRadiosurgeryApplicationsDifferenttechnologiesGammaKnifeLINAC-basedsystemsCyberKnife

三、ThemethologyandequipmentsforRadiationTherapyWhatisStereotacticRadiosurgery?Methodtonon-invasively&specificallytreatbenign/malignanttumorsandtissueabnormalitiesUsesmethodsofstereotactic3-DlocalizationofsurgicalsiteUsesradiosurgicaltechniquestoperformthe“surgery”3-DStereotacticLocalizationGoal:TotargetthetissueofinterestwithasmuchaccuracyaspossibleUseimagingand3-Dmappingtechniquestotargettissueofinterest4generalmedicalimagingmodalitiesused:X-RayPETMRIDigitalSubtractedAngiographyUsethepatientasareferenceforthelocalization2generalmethods:Framestereotacticlocalization(old)Framelessstereotacticlocalization(new)TheImagingModalitiesTomographicTechniques:PET(CT)andMRIGoodfortumorpathologiesUsemultiplelayerstoget3-DimageX-ray-basedTechniques:X-rayandDigitalSubtractedAngiographyGoodforvascularimaging(fortreatmentofvascularmalformations)Usepinsanddepthperceptionmethodstoget3-DlocalizationTypesofRadiationDifferswithdifferentmachines:High-energyX-rayFromlinearacceleratorsystemsGammaradationFromCobalt-60sourceProtonFromparticlebeamorcyclotronLimiteduseintheUSUsesBraggPeakprinciple:Asprotonslowsdown,itgivesoffdisproportionatelymoreenergyRightbeforeitstops,itgivesoffmostofitsenergy,resultinginapeakatthatdepthoftissueDifferentMachinesinUseGammaKnifeGammaradiationfromCobalt-60SourceUsemultiplebeamstotreattissuevolumeLINAC-basedsystems(X-Knife)High-energyX-rayfromLinearAcceleratordeviceUsefractionationCyberKnifeAlsoaLINACsystem,butLINACisonaroboticarmUsefractionationCanbeusedforpartsofbodyotherthantheheadLinearacceleratorDisplayoftreatmentplanning:GammaKnifeOver30yearsofclinicaluseandagreatdealofpublicationsTargetingPrecisionofwithin2mmMultipletargetscanbeeasilytreatedinonesessionLINAC-BasedSystems-Lessaccurate-Inuseinmorehospitals-Lessefficient(longertreatment times)CyberKnife-Cantreatmostregionsofbody-w/Stereotacticframe,canapproachaccuracyofLINACorGammaKnife-Real-timeframelessstereotaxycanbeused四、theknowledgesystemofRT

generalclinic肿瘤放射治疗的各种适应症治疗并发症的临床处理技术Oncology肿瘤病因及其流行病学关系肿瘤的分期分形肿瘤的生长规律及其引流方式肿瘤的临床诊断方法radiobiologyPhysicsofradiationtherapyandclinicDosimetry五、IntroductionofradiationPhysics

1.radiationphysicsisbranchofmedicalphysicsPhysicsofMedicalImaging医学影像物理学PhysicsofRadiationTherapy放射治疗物理学NuclearMedicalPhysics核医学物理学Themaincontentsof

MedicalPhysicsDefinitionofmedicalimagingphysics定义：医学影像物理学是用成像的物理原理和方法设计的各种成像装置，采集人体内部的解剖学、生理学和病理学的各种信息并实现可视化的科学。主要工作内容：该学科提供新的成像仪器和设备的设计原理和方法，改进这些仪器和设备的性能，对临床使用的仪器设备进行质量控制，对各种成像装置形成的图像进行综合分析和集成、为管理和通讯这些医学图像提供新方法和新技术，研制和开发及以这些新方法和新技术为基础的医学软件包。TheintroductionofMedicalPhysicshomeandabroad

国内外医学物理学教育概况American：TheAAPM（AmericanAssociationofPhysicistsinMedicine）wasestablishedin1958.In1999,therewereover5000membersinAAPM.About2/3ofthemworkinthefieldofradiationtherapy,othersinimagingdiagnosisandnuclearmedicine.China：Generally,theeducationofmedicalphysicsiscoveredinbiomedicalengineering.Thesubjectandcoursesmostlylayparticularstressonmedicalengineeringormedicalimagingdevices.

Table1:in1997PhysicistinradiationtherapyPhysicianinradiationtherapy423persons3440personsTheintroductionofMedicalPhysicshomeandabroad

国内外医学物理学教育概况1993年，AAPM在“医学物理学硕士学位的教学计划”中，列出10门课程位最低要求：AnatomyandPhysiology解剖学和生理学ImagingDiagnosis影像诊断学Electronics电子学HealthPhysics—radiationprotection保健物理----辐射防护Nuclearmedicine核医学MedicalandBiologyPhysics医学及生物