放射物理学英文版

放射物理学英文版第1页/共285页Whywestudythissubject?Diagnosticradiology放射诊断学Radiotherapy放射疗法Radiobiology放射生物学Nuclearmedicine核医疗学第2页/共285页Diagnosticradiology放射诊断学CTscanner;CT扫描 X-raymachine;爱克斯光机 DR; C-arms; PET;PerformanceEvaluationTest性能鉴定试验 radiologicalimaging放射影像学第3页/共285页CTSCANNERPET第4页/共285页Radiotherapy放射疗法

traditionalmethodstokilltumors治疗肿瘤的传统方法 clinicalphysicist;临床物理学家，医学物理师 TPS;TechnicalProblemSummary技术问题摘要

第5页/共285页Radiobiology放射生物学

theinteractionbetweentheradioactiveparticlesandthecells在放射性的粒子和细胞之间的交互作用 researchworktomaketheradiologymoreadvantageousforhuman研究工作让X光线学变得更有利于人类第6页/共285页Nuclearmedicine核医疗学

ECT,电休克治疗SPECT;单光子发射计算机化断层显像 verypopularabroad; brightfuture;第7页/共285页BasicConceptsQuantitiesandunits量和单位(physicalquantity)=(numericalvalue)*(someunit)Internationalsystemofunits(SI)单位的国际系统FundamentalUnits基本的单位Q:reviewthefundamentalunits? mass length time current第8页/共285页1.massmKilogram(kg)2.lengthl

meter(m)3.time4.currenttI

second(s)ampere(A)

BasicConcepts第9页/共285页BasicConceptsDerivedunits导出单位

velocity速度 ratio比率oftheincrement增长ofdistancetotime acceleration加速度ratioofthechangeofvelocitytotime force(newton)力（牛顿） relatedtoacceleration defined界定byNewton’slawofmotion 运动定律运动定律第10页/共285页BasicConceptsDerivedunits导出单位 workorenergy(joule焦耳) W=F*l power(watt),功率 rateofdoingwork frequency频率(hertz赫兹)numberofoscillationperunittime单位时间振动次数第11页/共285页Example1-1.

Ayoungscientistofmass75kgattheOntarioCancerInstitute,inafoolishtrialofendurance,ranfromthebasementtotheseventhfloor(height25.8m)in23.6s（在23.6秒中从地下室跑到七楼（高度25.8m）.Calculatetheworkdoneandthepowerdeveloped.InTorontotheaccelerationduetogravityis9.8ms-2.课本P4第12页/共285页BasicConceptsElectricalunits电单位 charge(coulomb)电荷(库仑)

1coulomb=1C=1amperesecond=1As

potentialdifference(volt)位差,电势差(伏特)Potentialdifference=

Electricalcircuits电路

Workdone=QV=ItV第13页/共285页BasicConceptsElectricalunits

capacity（电容）:abilitytostorecharge

resistance（电阻）第14页/共285页Example1-2.

Apotentialof12voltsplacedacrossaheatingcoil暖管producesacurrentof1.5amperes.Findtheresistance（电阻）ofthecoil,thechargewhichpassesthroughthecoilin1.0min,theenergydissipated（消耗的能量）,andpower功率developed.第15页/共285页Example1-3.

Acurrentof2.5×10-6Aflowsintoa20.0×10-6Fcondenser电容器for20seconds.Findthepotential（电势差）towhichthecondenserischarged.第16页/共285页BasicConceptsRadiationunits辐射单位

absorbeddose吸收剂量 energydeposited吸收byionizing（电离）radiationperunitmassofmaterial

1Gy=100rads=1J/kg

exposure曝光thecharge（电荷）liberated（释放）byionizingradiation(outputofanXraygenerator发生器)perunitmassofair1roentgen（伦琴）=2.58*10-4

Ckg-1

第17页/共285页BasicConceptsRadiationunits

activity活性thenumberofdisintegration（裂变）perunittimeofaradioactiveisotope（放射性同位素）unit:becquerel贝可勒尔(放射性强度单位,每秒有一个原子衰变)1Bq=1s-1

1Ci=3.70*1010Bq

第18页/共285页

第19页/共285页SummaryThephysicsofradiology（X光线学的物理学Fundamentalunits基本的单位Derivedunits导出单位Unitsusedinradioactivefield（放射领域）第20页/共285页ＴＨＥＰＨＹＳＩＣＳＯＦＲＡＤＩＯＬＯＧＹＢＡＳＩＣＣＯＮＣＥＰＴＳＰＡＲＴTWOBMECollegeShermansheen第21页/共285页Atoms原子Matteriscomposedbyatoms物质由原子组成StructureofAtoms nucleus(原子)核----radius半径10-14m

electronsclouds----radii半径10-10mAtomicnumber原子序数:Znumberofelectrons chemicalproperties化学特性第22页/共285页Constitution结构，构造protons(质子)neutrons(中子)Q:Howtoknowthestructureofthenucleus?Q:Propertiesofprotonsandneutrons:chargeandmassmassnumber(原子)质量数:A

protons+neutrons

neutrons=A-ZNucleus原子核nucleon核子第23页/共285页Isotope同位素definition(定义):Atomscomposedofnuclei[原子核(nucleus的复数形)]withthesamenumberofprotons(质子)butdifferentnumberofneutrons(中子)arecalledisotopes.

stable稳定的orunstable;disintegration（裂变）andradioactive; （放射性的）Nucleus原子核第24页/共285页AtomicMass原子质量Carbon碳massnumber原子序数12 representedbyA【massnumber(原子)质量数】Notationforatomicspecies原子种类的标记法

subscripts（下标）-Zandsuperscripts（上标）-AIsotopeofHydrogen氢,Helium氦,Cobalt钴(符号为Co),

第25页/共285页Hydrogen（氢）氢氢Z=1111012123StableStableRadioactiveProton(质子)Deuteron（氘核HydrogenDeuterium（氘Tritium（三重氢第26页/共285页Helium氦Z=232He42He52He62He82He222221234634568StableStableRadioactiveRadioactiveRadioactiveAlpha（α）第27页/共285页Elementalparticles基本粒子

p—proton1.007277,+1

Theprotonisthenucleusofthehydrogenatom.Thehydrogenatomconsistsof1protoninthenucleusand1external（外部的）electron.Themassoftheneutralatom（中性原子）is1.007277+0.000548=1.007825massunits.Theprotonisoneofthefundamentalbuildingblocksofallnuclei.Beams（束,柱）ofprotonsarebeingusedinradiotherapy.（放射疗法）

第28页/共285页Elementalparticles基本粒子n—neutron1.008665,0

Theneutron(中子)istheotherfundamentalbuildingblockofallnuclei.Neutronshavenearlythesamemassasprotons.Sincetheneutronsisanunchargedparticle（不带电粒子）itishardtostopanddifficulttodetect（查明，发现，发觉.）Beamsofneutronsarebeingusedinradiotherapy.

第29页/共285页Elementalparticles基本粒子

e-β-0.000548,-1Theelectronhasaverysmallmasscomparedwiththeproton.Electronsaboundinnature.Everyatomcontainselectronsoutsidethenucleus.Theelectroniseasilydetected.Itissometimescalledanegatron（阴电子）orbetaparticle（β粒子）andrepresentedbye,e-orβ-.Beamsofhighenergyelectronsareextensively（广泛地）usedinradiotherapy.第30页/共285页Elementalparticles基本粒子

e+β+0.000548,+1Thepositron（正电子）hasthesamemassasanelectronbutcarriesapositivecharge.Positronsexistinnatureonlywhiletheyareinmotion（在运转中;处于兴奋状态）.Aslowlymovingorstationary(静止的)positronquicklycombineswithanelectrontoformaburst(爆炸,爆裂)ofradiationintheformof（用…的形式）twogammarays（γ射线）(seebelow).Positronsarerepresentedbye+,orβ+andreferredtoasbetaplusparticlesTheyareusedinnuclearmedicine（核医疗学）.第31页/共285页Elementalparticles基本粒子

Hvγ,0,0Strictlyspeaking,thephoton（光子）isnotaparticle,butabundle一捆ofenergywhichtravelsatthespeedoflight(3×108ms-1).Inmanyinteractions（相互作用）itactsmuchlikeaparticle.Photonsarereferredtoalmostinterchangeably（可替换地）asquanta量子(quantum的复数形式)orgammaraysandarerepresentedsymbolically（象征性地）byhνorγ.Beamsofphotonsaccountforthemajorpartofexternalbeam（外粒子束;外束）radiotherapy（放射疗法）.

第32页/共285页Elementalparticles基本粒子neutrino中微子νe~,0Theneutrino（中微子）isaverysmallparticlewithpractically（几乎）nomassandnocharge.Forthisreason,ithasbeenverydifficulttodetectexperimentally（根据实验地）.Itsinteraction（相互作用）withprotonstoformneutronsandpositronsaccordingtothereaction（反应）νe+p→n+β+hasbeenobserved.Theneutrinowasintroducedoriginallyfromtheoretical（假设的，理论的）considerationstohelpexplainbetadecay（衰变）.第33页/共285页Elementalparticles基本粒子

Mumesons（介子）,μ+

,μ-,207m0,+1or-1

Mumesonsmaybeeitherpositivelyornegativelycharged（带负电荷的）andhaveamass207timesthemassoftheelectron.Theyareproducedindirectly（间接地）bytheinteractionofveryhighenergyparticleswithmatter（物质,物体）.Theparticlesareunstableanddecayspontaneously（自发地衰变）intoelectronsandneutrinos（中微子accordingtothereactionsμ+→e++2νμ-→e-+2νThemeanlife（平均寿命）oftheparticlesis2.15×10-6sec.第34页/共285页Elementalparticles基本粒子Pimesons（介子）,π+273m0+1π-273m0-1π0265m00Pimesonsmayhaveapositiveanegativechargeormaybeneutral（中性的）.Theyareproducedbythebombardment（炮击；轰炸）‘ofmatterwithhighenergyprotonsorphotons.Thechargedπmesonsdecayintomumesonsandneutrinos（中微子）accordingtoπ+→μ++νπ-→μ-+νwithameanlifeof2.5×10-8s.Theneutralπ0mesondecays（衰变）into2photonsπ0→hν1+hν2withameanlifeof10-15seconds.Beamsofnegativeπmesonsarebeingusedinradiotherapy（放射疗法）.

第35页/共285页Elementalparticles（放射疗法）

p—proton1.007277,+1n—neutron1.008665,0

e-β-0.000548,-1

e+β+0.000548,+1

Hνγ0,0

νe~,0

Mumesons207m0,+1or-1Pimesons273m0,+1or-1265m00

第36页/共285页Extranuclearstructure核外的结构Arrangementofplanetaryelectrons行星式电子outsidethenucleus第37页/共285页Theoutermostorbit最外层轨道Chemicalpropertiesandvalence(化合)价repeatinertgas惰性气体:He,Ne,…alkalineelements碱性元素:lithium锂,sodium钠,…Extranuclearstructure行星式电子—

chemicalproperties化学特性第38页/共285页AtomicEnergylevels原子能级Opticalradiation光辐射andXradiation第39页/共285页NuclearEnergylevels核能级Gammaray（伽马射线,γ射线）伽马射线,γ射线第40页/共285页Quantumnature（量子种类，性质）ofradiation

Quantum(量子)orPhoton（光子）bundleofenergy能量束EnergyofaPhotonForadiagnostic（诊断的）X-rayGenerator（发生器）,wavelength（波长）10pm,1photon:第41页/共285页QuantumnatureofradiationImportantequation方程式,等式

Wavelength（波长）andenergy

Quantumnatureandcontinuousradiation连续辐射第42页/共285页ElectromagneticSpectrum

电磁波频谱Frequency(Hz)频率Wavelength波长PhotonEnergyProperties特性1.0×1053.0×10103km0.01m413peV124μeVRadiowaves（无线电波）ranging（排列）fromlongwavesthroughthebroadcastband（广播波段;广播频带,toshortwavesandtoultra（极端的）shortwavesinradar（雷达）.Thesewavesareproducedbyelectricaloscillations（振荡）anddetected（发现;发觉,查明）byelectronicequipment.Theywillpassthroughnonconductinglayers（不传导层）ofmaterialsbutarereflected（反射）byelectricalconductors.（导电体;电导线）第43页/共285页ElectromagneticSpectrum电磁波频谱Frequency(Hz)WavelengthPhotonEnergyProperties特性3.0×10123.0×1014100μm1μm12.4meV1.24eVInfraredradiations（红外辐射）.Theseareproducedbymolecularvibration（分子振动）andtheexcitation激发(过程)oftheouterelectronsoftheatom.Theyaregenerated（产生）byheatinstores（堆积物）,radiators（散热器）,etcetera（及其他,等等）,andcanbedetectedbyheatdevices（装置,设备）andfilms（薄层，胶卷）.Mostsolidmaterialsareopaque（不透明的）toinfraredradiations.第44页/共285页ElectromagneticSpectrum电磁波频谱Frequency(Hz)WavelengthPhotonEnergyProperties4.3×10147.5×1014700nm400nm1.77eV3.1eV

Visiblelight（可见光）rangingfromredthroughyellow,greenandbluetoviolet紫.Producedbytheexcitationoftheouterelectronsofanatom.Generated（产生）inlampsandingastubes（导气管）byelectricaldischarge（释放，排放出的物体）.Detectedbyfilms,byphotoelectriccells（光电管）,andbytheeye.Transmitted（传播）bymaterialssuchasglass.第45页/共285页ElectromagneticSpectrum电磁波频谱Frequency(Hz)WavelengthPhotonEnergyProperties7.5×10143.0×1016400nm10nm3.1eV124eVUltravioletlight（紫外辐射;紫外光）.Producedbytheexcitationofouterelectronsintheatom.Detectedbyfilms,Geigercounters盖格计数器（用于测量放射性）,andionizationchambers（电离室）.Produceserythematic（红斑）oftheskin;killsbacteria（细菌）andisanagent（原动力,动因;作用剂）intheproductionofvitaminD.第46页/共285页ElectromagneticSpectrumFrequency(Hz)WavelengthPhotonEnergyProperties3.0×10163.0×101810nm100pm124eV12.4keVSoftxrays.Producedbytheexcitationoftheinnerelectrons（内层电子）ofanatom.Detectedbyfilms,Geigercounters,andionizationchambers.Havetheabilitytopenetrate（穿过）verythinlayersofmaterial.Oflittlevalueinradiology（放射学,辐射学）becauseoftheirlimitedpowerofpenetration.穿透能力3.0×10183.0×1019100pm10pm12.4keV124keVDiagnosticxraysandsuperficial（表面(上)的）therapy（治疗，疗法）.第47页/共285页ElectromagneticSpectrumFrequency(Hz)WavelengthPhotonEnergyProperties3.0×10193.0×102010pm1pm124keV1.24MeVDeeptherapy（深部疗法）xraysandgammaraysfromradiumdecayproducts（镭衰变产物）.3.0×1021100fm12.4MeVRadiationfromasmallbetatron（电子感应加速器）orlinearaccelerator（直线加速器）.3.0×102210fm124MeVRadiationfromalargelinearaccelerator.3.0×10231fm1.24GeVProducedintheoperationoflargeprotonsynchrotrons（同步加速器）orlinearaccelerators（直线加速器）.第48页/共285页ElectromagneticSpectrumFrequency(Hz)WavelengthPhotonEnergyProperties1.0×1053.0×10103km0.01m413peV124μeVRadiowavesrangingfromlongwavesthroughthebroadcastband,toshortwavesandtoultrashortwavesinradar.Thesewavesareproducedbyelectricaloscillationsanddetectedbyelectronicequipment.Theywillpassthroughnonconductinglayersofmaterialsbutarereflectedbyelectricalconductors.3.0×10123.0×1014100μm1μm12.4meV1.24eVInfraredradiations.Theseareproducedbymolecularvibrationandtheexcitationoftheouterelectronsoftheatom.Theyaregeneratedbyheatinstores,radiators,etcetera,andcanbedetectedbyheatdevicesandfilms.Mostsolidmaterialsareopaquetoinfraredradiations.4.3×10147.5×1014700nm400nm1.77eV3.1eVVisiblelightrangingfromredthroughyellow,greenandbluetoviolet.Producedbytheexcitationoftheouterelectronsofanatom.Generatedinlampsandingastubesbyelectricaldischarge.Detectedbyfilms,byphotoelectriccells,andbytheeye.Transmittedbymaterialssuchasglass.7.5×10143.0×1016400nm10nm3.1eV124eVUltravioletlight.Producedbytheexcitationofouterelectronsintheatom.Detectedbyfilms,Geigercounters,andionizationchambers.Produceserythematicoftheskin;killsbacteriaandisanagentintheproductionofvitaminD.3.0×10163.0×101810nm100pm124eV12.4keVSoftxrays.Producedbytheexcitationoftheinnerelectronsofanatom.Detectedbyfilms,Geigercounters,andionizationchambers.Havetheabilitytopenetrateverythinlayersofmaterial.Oflittlevalueinradiologybecauseoftheirlimitedpowerofpenetration.3.0×10183.0×1019100pm10pm12.4keV124keVDiagnosticxraysandsuperficialtherapy.3.0×10193.0×102010pm1pm124keV1.24MeVDeeptherapyxraysandgammaraysfromradiumdecayproducts.3.0×1021100fm12.4MeVRadiationfromasmallbetatronorlinearaccelerator.3.0×102210fm124MeVRadiationfromalargelinearaccelerator.3.0×10231fm1.24GeVProducedintheoperationoflargeprotonsynchrotronsorlinearaccelerators.第49页/共285页ElectromagneticSpectrum第50页/共285页Bindingenergy结合能

Kradiation,BE:70000ev Lradiation,BE:11000evMradiation,BE:2500evRadiationofenergy（能量辐射）

fromanatom第51页/共285页Radiationofenergy

fromanatom第52页/共285页summaryAtoms原子TheNucleus原子核ElementalParticles基本粒子ExtranuclearStructures核外结构AtomicEnergyLevels原子能级NuclearEnergyLevels核能级ElectromagneticRadiation电磁辐射QuantumNatureofRadiationTheElectromagneticSpectrum电磁波频谱RadiationofEnergyfromanAtom原子的能量辐射第53页/共285页ＴＨＥＰＨＹＳＩＣＳＯＦＲＡＤＩＯＬＯＧＹＢＡＳＩＣＣＯＮＣＥＰＴＳＰＡＲＴThreeBMECollegeShermansheen第54页/共285页Massandenergy质量和能量，质能Einstein’stheory

E=mc2

C代表光速Energycorrespondingtooneelectron能量相当于1kgm2S-2=1joule

Because:第55页/共285页Massandenergy质能massofonecarbonatom=Example1-7.Calculatetheenergyequivalent(能当量)of1atomicmassunit(amu).

Avogadro'snumber(阿伏伽德罗数)=6.022045×1023

carbonhasamassnumber【(原子)质量数】

of12,itcontains12amuHence,theconversion（转化）of1amutoenergy

第56页/共285页twoimportantmass-to-energyconversionfactors转换因数:第57页/共285页Massandvelocitym0,therestmass静止质量1/10thevelocityoflight,increaseinmassof0.5%98%oflight(v/c＝0.98),5timesoftherestmass第58页/共285页MassandvelocityKineticEnergy（动能）ElectronsProtonsTotalEnergy(MeV兆电子伏)VelocityRelativetoVel.ofLightMassRelativetoRestMass（静止质量）VelocityRelativetoVel.ofLightMassRelativetoRestMass10keV100keV200keV500keV1MeV2MeV5MeV10MeV20MeV50MeV100MeV0.5210.19501.0200.6110.54831.1960.7110.69541.3921.0110.86291.9791.5110.94112.9572.5110.97914.9165.5110.995710.7910.5110.99881720.5820.5110.99968940.1650.5110.99994999.01100.5110.999987192.310.00461.00000.01471.00010.02081.00020.03261.00050.04651.00110.06571.0020.10261.00530.14511.01070.20331.02130.31411.05330.42831.1066第59页/共285页Exponentialbehavior指数式变化

therateofchangeofafunction（函数）isproportional（比例的,成比例的）tothefunction.Ifaquantitychangesbyacertainfactor（一个特定的因素）inagivenintervaloftime（时间间隔）,thentherewillbeexponentialbehaviorifinanyotherequalintervaloftime（相等时间间隔）itchangesbythesamefactor相同的因素第60页/共285页Exponentialbehavior指数式变化thegrowthofmoneyinabankaccount银行存款,thegrowthofpopulations,thegrowthofcells,thedecay（衰变）ofradioactiveisotopes（放射性同位素）

thekillingofcellsbyradiation,theattenuation（变细；变薄;减弱）ofxraybeamsOccurred（发生）while:第61页/共285页EXPONENTIALDECAY（指数式衰减）OFARADIOACTIVEISOTOPE－HALF-LIFE（半衰期）ontheaverage,afterthehalf-life,halftheradioactiveatoms（放射性原子）willdisintegrate（破裂〔分裂）.Inthenexthalf-life,one-halfoftheremaining（剩下的）atomswilldecay.

Forexample,asourceofradioactivegold(198Au)withahalf-lifeof2.69days,,startedwith100×106atoms,after2.69daystherewouldbe50×106remaining,after5.38days25×106,after8.07days12.5×106.第62页/共285页EXPONENTIALDECAYOFARADIOACTIVEISOTOPE－HALF-LIFE第63页/共285页EXPONENTIALDECAYOFARADIOACTIVEISOTOPE－HALF-LIFEMathematicalrelation数学关系:substitutingt=th,2th,3th.（取代）Thenumber,N,afterthesetimesisN0/2,N0/4,N0/8

第64页/共285页EXPONENTIALDECAYOFARADIOACTIVEISOTOPE－HALF-LIFEExample1-8.Calculatethenumberofatomsof198Au(th=2.69days)after7daysifinitially（开始,最初）therewere108atomspresent.

Wenowdetermine（测定）withacalculator（计算器）that22.60＝6.06

atoms

e0.693=2.00

N=N0(2)-t/th=N0(e0.693)-t/th=N0e-0.693t/th

Decaytime(inunitsofhalf-lives)=

第65页/共285页Transformationconstant

变换[衰变,转变]常数△N=-λN△t,provided（只有…才）

λ△t<<1

dN=-λNdt

N=N0e-λt

第66页/共285页Exponentialgrowthofcells

细胞的指数生长△N=+λN△t

itssolutionleadsto

N=N0eλtandλ=Exponentialkillingofcells△N=-λN△D

N=N0e-λD=

N0e-D/D0第67页/共285页Graphsshowingexponentialgrowthofcellsandexponentialkilling（指数式消灭）ofcells.

第68页/共285页Exponentialattenuation

指数减弱△N=-μN△xN=N0e-μx

μ,thelinearattenuationcoefficient线性衰减系数

thesolutionis

:iscalledthehalf-valuethickness（半吸收厚度;半值层;强度减半厚度）,orhalf-valuelayer

第69页/共285页SummaryofExponentialBehaviorProcess(过程,进程)Variable(变数)ConstantofProportionality(常数比例)UsefulRelationsUsualEquation(方程式,等式)Radioactivedecayofatoms,Ntime,ttransformationconstant,λ（变形常数）meanlife,th=1/λhalf-lifeth=0.693/λGrowthofinvestment（投资），Vtime,tinterestrate,r（利率）doublingtime（倍增时间）,td=0.693/rGrowthofpop.ofcells,Ntime,tgrowthconstant（常数）,λdoublingtime,td=0.693/λKillingofcells,N,byradiationdose,D（剂量）killingconstant,λmeanlethaldose,D0=1/λdosetokill50%,Dh=0.693D0Attenuation（变细；变薄;减弱）ofabeamofphotons,Nthickness,x（厚度）attenuationcoefficient,μ（变薄系数）meanfreepath,1/μhalf-valuelayerxh=0.693/μ第70页/共285页summaryMassandenergyMassandvelocityExponentialbehavior第71页/共285页ＴＨＥＰＨＹＳＩＣＳＯＦＲＡＤＩＯＬＯＧＹTheProductionandPropertiesofXRaysPartOneBMECollegeShermansheen第72页/共285页X-RayTubes（X射线管）andSimplifiedCircuit单一化的线路Q:HowtoproduceXradiation?Substance(物质，物)bombarded(轰击)byhighspeedelectronsX-raytubeQ:StructureofanXraytube?

cathode（阴极）,anode（阳极）,filament(灯丝),focusingcup(聚焦杯)第73页/共285页X-RayTubesandSimplifiedCircuitAbigproblem?

----efficiency（效率,效能）----NobelprizeUnderstandX-raytubeinacircuit

spacecharge（空间电荷）effectsaturation饱和（状态）tubevoltage（管电压）increased filamentemission（灯丝发射）第74页/共285页X-RayTubesandSimplifiedCircuit第75页/共285页X-RayTubesandSimplifiedCircuitThreeimportantparameters（参量）Tubecurrent管电流Filamentcurrent灯丝电流KVanode-cathode伏特阳极－阴极Akindofspecialtubesgrid-controlledtubes控制栅电子管rapidswitchingandshortexposuretime迅速的转变和短暴露时间第76页/共285页Self-rectified（自整流）

Xraycircuit第77页/共285页Self-rectifiedXraycircuit

自我整流的X光线路Somebasicconcepts transformer变压器 ironcore铁芯 primarywinding初级线圈 secondarywinding复卷绕组linecompensate线补偿 milliammeter毫安表 filamentcontrol灯丝调节第78页/共285页AlternatingCurrents&Voltages交流电＆电压第79页/共285页Rectification（整流）thetargetofanxraytubehotenoughtoemit（发出，射出）electronselectronswillflowfromanode（阳极）tocathode（阴极）theinversecycle逆循环thedelicatefilament（细灯丝）willbedestroyed第80页/共285页Siliconrectifier硅整流器第81页/共285页Halfwave&fullwave（全波）第82页/共285页Threephaseunits三相单位第83页/共285页AnodeandCathodeStructureDiagnosticxraytubesproduceasharpshadowpicture

"pointsource"and"veryshortexposure"

thelinefocustube

行聚焦管

rotatinganodetube旋转阳极管

第84页/共285页

Diagramsillustratinganodeconstructionandfocalspots（焦斑(点)）.(a)Linefocusfixedanode（行聚焦固定的阳极）.(b)Linefocusrotatinganode（旋转阳极）,viewedfromtheend.(c)Linefocusrotatinganodeviewedfromtheside.(d)Alternativearrangement（间隔布置）ofrotatinganodeusingtwoseparate"tracks"atdifferentanglesasintheSiemens"Biangulix"series.（替换以不同的角度使用两个分开"轨道"的阳极为在姆欧的新项目中"Biangulix"系列的间隔布置）。第85页/共285页Rotatinganodetube（旋转阳极管

）,adaptedfromdiagram图解、示意图byPhilips.第86页/共285页AnodeandCathodeStructureRadiotherapyxraytubesLargeaverageenergy&focalspot

焦斑(点)Problem:secondaryemission次级发射Hoodedanode被罩上的阳极

第87页/共285页Hoodedanodetherapytube被罩上的阳极治疗管adaptedfromdiagrambyPhilips

从飞利浦公司的图表适应第88页/共285页summaryX-raytubeandsimplifiedcircuitX射线管和单一化线路Rectification整流Threephaseunit三相单位Anodeandcathodestructure阳极和阴极结构第89页/共285页ＴＨＥＰＨＹＳＩＣＳＯＦＲＡＤＩＯＬＯＧＹTheProductionandPropertiesofXRaysPartTwoBMECollegeShermansheen第90页/共285页RatingsofDiagnosticTubes诊断管的等级，类别First,thefocalspot焦斑(点)mustnotbeloadedbeyondacertainpowerinput.（负载超过特定输入功率）Second,theanodemustnotbeloadedbysuccessiveexposuresbeyondacertainlimit.（负载超过一个特定界限的连续曝光）Finallythehousing（外壳,外罩）mustnotbeexpectedtodissipateitsenergyatratesbeyondacertainvalue.（预期在特定的价值之外的比率驱散它的能量)第91页/共285页Example2-1.Calculatetheriseintemperature(升温)ofarotatinganodeafteranexposureof100mAfor2satconstantpotentialof100kV.Assume(假设)thetargettohaveamassof500gandthesurfaceareaofthebombardedregion(被轰击的区域)tobe30cm2;takethedensityoftungsten（钨的密度）tobe19.3g/cm3andspecificheat（比热）0.03calg-1oC-1.Performthecalculationsfortwolimitingconditions（限制条件）:(a)assumetheheatinstantlydistributesitselfoverthewholeoftheanodeandnoneislostbyheattransfer（假设热量立即扩散到整个阳极且没有传热的损失）;(b)assumenoheatescapesfromtheimmediateareaofthebombardedregionbutisconcentratedtoadepthof1mmunderthebombardedarea.（假设没有热量从当前被轰击的区域逃出但是集中到在被轰击的区域下面的1毫米的深度）第92页/共285页Energyinput（能量输入）=100×103V×0.1A×2s=2×104J

Heatinputtoanode=2×104J=2×104/4.18cal

≈5×103calForwholeanode,thermalcapacity（热容量）=500g×0.03calg-1

OC-1=15cal

OC-1(a)Riseintemperature=

(b)Massofbombardedvolume=30×0.1cm3×19.3gcm-3=58g

Riseintemperature=

4.18J=1calorie卡路里,卡(热量单位)第93页/共285页theaveragetubecurrentinmA,thepeakvoltage(峰值电压)inkV,theexposuretime（曝光时间）insecondsHU:aheatunit(热量单位)HU=voltage(kV)×current(mA)×time(s)

Energydeposited（能源储存）≈0.75HUjoules

Inpracticalengineering（在实际的工程学中）:第94页/共285页XraySpectra（X光谱）第95页/共285页Interactions(相互作用)ofElectronswiththeTargettoGiveXRays(X光)ionizationalcollisions(离子化碰撞)_ ionization（电离）produced,deltarays（三角线）,heatenergy（热能）,

radiativecollisions（辐射碰撞）highspeedelectronhitting(碰撞)massChancesdependontheenergyoftheelectron第96页/共285页Typicalelectroninteractionswithatarget典型的一个目标的电子相互作用第97页/共285页CharacteristicRadiation

标识辐射CriticalXrayAbsorptionEnergies(keV)X光吸收能量Shell外壳OxygenZ=8Calcium钙Z=20Copper铜Z=29Molybdenum钼Z=42Tin锡Z=50Tungsten钨Z=74Lead铅Z=82K0.5334.0378.98120.00029.20069.52588.004LILIILIII0.0240.0090.0091.4380.3500.3461.0960.9