放射治療劑量學1課件

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.

安東尼·亨利·貝克勒爾（AntoineHenriBecquerel，1852—1908年），法國物理學家。1896年3月，貝克勒爾發(fā)現(xiàn)，與雙氧鈾硫酸鉀鹽放在一起但包在黑紙中的感光底板被感光了。他推測這可能是因為鈾鹽發(fā)出了某種未知的輻射。從而確認了天然放射性的發(fā)現(xiàn)。

二、DevelopmentofRadiationTherapy后來，居里夫婦將其稱為“放射性”?，F(xiàn)在，我們稱其為天然放射性。盡管貝克勒爾當時錯誤地認為它是某種特殊形式的熒光，但天然放射性的發(fā)現(xiàn)仍不愧是劃時代的事件，它打開了微觀世界的大門，為原子核物理學和粒子物理學的誕生和發(fā)展奠定了實驗基礎。ThisphenomenonwasstudiedbyPierreandMarieCurieandwaslaternamedradioactivitybythem.In1903,theCuriessharedwithHenriBecquereltheNobelprizeinphysicsfortheirinvestigationofuraniumandradioactivematerial.DevelopmentofRadiationTherapy關(guān)于curie介紹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（有絲分裂）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腫瘤治療五年生存率的變化年代20世紀初30年代60年代90年代五年生存率5%15%30%45%表2三大治療手段對腫瘤治愈率的相對貢獻治療手段手術(shù)治療放射治療化學治療相對貢獻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腫瘤放射治療的各種適應癥治療并發(fā)癥的臨床處理技術(shù)Oncology腫瘤病因及其流行病學關(guān)系腫瘤的分期分形腫瘤的生長規(guī)律及其引流方式腫瘤的臨床診斷方法radiobiologyPhysicsofradiationtherapyandclinicDosimetry五、IntroductionofradiationPhysics

1.radiationphysicsisbranchofmedicalphysicsPhysicsofMedicalImaging醫(yī)學影像物理學PhysicsofRadiationTherapy放射治療物理學NuclearMedicalPhysics核醫(yī)學物理學Themaincontentsof

MedicalPhysicsDefinitionofmedicalimagingphysics定義：醫(yī)學影像物理學是用成像的物理原理和方法設計的各種成像裝置，采集人體內(nèi)部的解剖學、生理學和病理學的各種信息并實現(xiàn)可視化的科學。主要工作內(nèi)容：該學科提供新的成像儀器和設備的設計原理和方法，改進這些儀器和設備的性能，對臨床使用的儀器設備進行質(zhì)量控制，對各種成像裝置形成的圖像進行綜合分析和集成、為管理和通訊這些醫(yī)學圖像提供新方法和新技術(shù)，研制和開發(fā)及以這些新方法和新技術(shù)為基礎的醫(yī)學軟件包。TheintroductionofMedicalPhysicshomeandabroad

國內(nèi)外醫(yī)學物理學教育概況American：TheAAPM（AmericanAssociationofPhysicistsinMedicine）wasestablishedin1958.In1999,therewereover5000membersinAAPM.About2/3ofthemworkinthefieldofradiationtherapy,othersinimagingdiagnosisandnuclearmedicine.China：Generally,theeducationofmedicalphysicsiscoveredinbiomedicalengineering.Thesubjectandcoursesmostlylayparticularstressonmedicalengineeringormedicalimagingdevices.

Table1:in1997PhysicistinradiationtherapyPhysicianinradiationtherapy423persons3440personsTheintroductionofMedicalPhysicshomeandabroad

國內(nèi)外醫(yī)學物理學教育概況1993年，AAPM在“醫(yī)學物理學碩士學位的教學計劃”中，列出10門課程位最低要求：AnatomyandPhysiology解剖學和生理學ImagingDiagnosis影像診斷學Electronics電子學HealthPhysics—radiationprotection保健物理----輻射防護Nuclearmedicine核醫(yī)學MedicalandBiologyPhysics醫(yī)學及生物