Physics X-Ray Tube PDF

November 81895WilhelmRoentgendiscoveredxrayswhileaccidentallyenergizingatube ayearlater1st evermedicalxraywastaken thefluoroscope ThomasEdisondiscovered 1901Roentgen got1stn...

November 81895WilhelmRoentgendiscoveredxrayswhileaccidentallyenergizingatube ayearlater1st evermedicalxraywastaken thefluoroscope ThomasEdisondiscovered 1901Roentgen got1stnobelprizeinphysicsforhisdiscovery 1904CharlesDally Edison'sassistantdied 1ˢᵗradiationrelatedteath SkinErythemaDose 1ˢᵗandonlyexistingunitofmeasurementcausesreddeningoftheskinfollowingexposure NationalCouncil RadiationProtectionidentified1st radiationdoselimits ALARAaslowasreasonably achievable on General Conference ofweightsandmeasurements establishedinternalsystemofunits Roentgenmeasuresradiationinair Radabsorbeddoseofthept Consumerradiation In Ire actoflast foraccrediationandlicesingstandardsfortechs standards ElectromagneticSpectrum everything is organizedby 1Theirenergylevel 2Frequency 3Wavelength Everything on the electromagnetic spectrumtravels atthespeed oflight speed velocity electrons are12 speed of light photons are speed oflight Allwaves are represented bytheirwaveform Frequency arethepeaks Mw Crest pulse peak wavelerffffh.gg fff g nr ftp.fnefgenff Trough low point Frequency and wavelengthinverserelationship Frequency and energydirectrelationship Unit of measurement WavelengthAngstrom xrayrangesfrom 1 5 EÉnergietert Waveparticleduality electromagnetic radiationcanbehavelikewavesorparticles iiininiaiiniiiiiiiiiiiaiiiiiiii.in Potentialenergy energy atrest PEmgh massgravitationalforceheight Kineticenergyenergy motionKE in mv massvelocity formofheat Thermalenergy energyinthe Unit Calorie Calorietheenergy neededtoraisethetemperatureof gramofwater 1 c Physical properties ofXrays 1highlypenetrating 2travel in straightlines 3neutralcharge 4heterogenous 5causematterto flouresce 6effectphotographicfilm 7scatterradiation iiiiiiii.mn Electromagnetism interaction bw electricalandmagneticfields Physics studyofthe interaction bw matter andenergy Radiationphysics dealsw electromagnetism andmechanics mechanics motion factorsintoradiation physics Termsthatdescribemotion Vector anddirection ex 30milessouth magnitude Scalar onlymagnitude ex30miles Newton'sFundamentallaws motion of anobjectin motionstaysinmotionobjectatrestremainsatrest force on anobjectisequaltoitsmasstimesitsacceleration force pushorpull F m a inertia an object atrestwillremainatrest Toeveryiconthey is inmecial andoppositereaction Terms Acceleration rate atwhichvelocitychanges w time to remaininmotion momentumcausesanobjectinmotion Workenergyusedagainst aforce pierateFilingwork SIunit Watt Lawof conservation ofenergy energyis neithercreaterordestroyedonlychangedfromoneformtoanother speed does not change ever processesofheattransfer Conductiondirect from transfer nottocold convectionheat transfer by amovinggasorfluid heatinthe Radiationradiate formofinfraredraysemitreddishglow Xraytube generates xraysfromaccierationthensuddendecleration thetubegoingfromkineticenergytoneat electronsmoveacross Components Protective housing leadlined contains oilinsulatesandpreventsshockhelpsdissipate neat preventsexcessiveradiationexposureandshocktotechand pt provides mechsupport x raysemittedin isotropicmannergetabsorbedby theleadonly xraysemittedthroughthewindowareuseful Reduces leakagerad maxamountofleakage 100 MRhr 1meterfromthetube Glassenvelope encasestheanodeandthecathode madeofpyrexglass maintains a vacuuminsidethetube tokeep outgasDegassingremovesairfromthexraytube Agingcausestungstentovaporize andcreatescoatingwhichcausesthetubecurrentto changeandtubeto fail metalenvelope is usedin moderntubes longertubelifeandefficientxrays ifgasgetsin electronflowisreducedandmoreheatis generatedtubefails Cathode negativesideinsidetheglassenvelope containscoilsofwiretungstenfilaments it 21thoriumaddedtoincreasetube life andenchancethermionic emission focusingcup made of molybdenumornickel directs electronstreamtowardanodeHasanegative chargelimiting spreadof electronsfromfilament smallfilament improves spatialresolution largefilament betterfor largerbodypartsandwhenusinghighertechniquesandproducing heat ual focustubehas2filaments Ers iii iii iii iii the rotor ofthe induction motor is locatedoutsidetheenvelope xrayphotonsthatexitthroughthetubes window are usefulbeam Anode insideoftheglassenvelope side Wherethe production ofxrays happens andradiatesheatandx raysfromthetarget conductselectricity Serves as a primary thermal conductor fromcathodetobackintoXraycircuit Types ofanodes Stationary hasrhenium alloyedtungstenattheendof a copperrod not asefficientusedin lowpowerandcurrentsuchasportablesanddental Rotating produces highintensity x ray in ashorttimeIn mostdiagnostictubes Normalrotation 3400RevolutionsPerMinute Allowsthebeamto interactw a largertargetareaallowsforhighertubecurrent Longerexposuretime Greatheatloadingcapacityincreasingtherotationimprovesheatcapacity Madeup ofTungsten74 w addedRheniumsurfacewhichaddsstrengthtohandlerotationspeedandheat Highmeltingpointandatomic conductsheatverywell molybdenumbase thermalinsulationto increaseheatloadcapacity Copper Rotor attachestoanode to dissipateheat Line FocusEntitle IE swPYfotducinghes image while managing neatLargeactualfocalspotsmalleffectivefocalspot Goal is to produce asmalleffectivefocalspotwhileutilizingthelargestareaonthetargetaspossible Results inbetterdetailandbetterheatdissipation 2focalspots EE thepatient focalspotproducesthebestdetail smalleffective Actualfocalspot bywhetheryou'reusingsmallorlargefilamentssincethat'swhereyourelectronsarecomingfrom determined determined bythesizeofthefilamentSmallfilamentsusesmallactualfocalspots Largeactualfocalspotlosesdetailsmallactualhasmoredetails Effective focalspot notdeterminedbyfilamentdeterminedbytheanodeangle usually 12 biggeranglethenlarger effectivefocalspot rangesfrom7 17 smaller anodeanglesmallertheeffectivefocalspotwhichincreasesrecordeddetail Betterto use largeractualspots sothatheatismoreevenly dispersed lessdamagingbut atthesametimeusesmalleffect focalspots to betterdetail get smallfocalpointgenerates moredetail Anode heeleffect when electrons travel across thetube andhit anode the intensitydiverge intensity is less atthe heel anode anode absorbs the photons ex if CRintensity is100 Cathode mightbe 120 whileanode is at 75 the anodeblocksandabsorbs the photonsandstopsthemfrom goingintothe patient sothe intensity is lower the intensity at cathode is muchhighersince it doesnotabsorb X ray production during an exposure mostofthe kinetic energy is convertedinto heat filament is heatedbycurrentflowingcausingelectrons to boil off which is called thermionic emission Xrays are producedwhenelectronsthatare producedthrough thethermionic emissionare accelerated from the cathode to anode distance b w them is 1cm X rays produced atthe focalspot are thegoodhigh energy photons electrons that don't hittheanode at thefocalspot are called off focus radiation Low energy X ray photons hit the pt andgettransferred tothe pt body high energy goesthrough and not get absorbed by the pt S heCelfctionsfettieachothercausing anelectroncloud aroundfilamentwhich is called space charge quickly you accelerate more electrons fall off When selectingtechnical factors selectkVpandmAsthatcanboil offelectrons Lowkvp andhigh mA high space charge a lot of electrons sitting atthefilament HighKVP and low mA low space charge moreelectrons are emittedfromfilamenttoanod at high kvp more electrons areemittedfromfilamentaredriven to anode MAandKVP MA electronstotal of electrons to boil off KVP voltagethat accelerates electrons across the tube Higherkvp increases the kineticenergy better accelerates the electrons Once electrons areboiled off voltage is what pushes themacross thetube electrons moving are called tubecurrent Heatproduction at theanode electrons interact w the orbitalelectrons oftarget atom convertingKEto thermalenergy 99 and electromagnetic 1 1 x rays increasing tube current increasesheatin the anode heatcomesfrom KE fromelectrons increasingkVpincreases heat produced attargetand photon production efficiency X raytube interactions interactionsthat happen inthetubefromelectrons andtungsten atoms in the anode Characteristics X ray make up verysmallno ofprimarybeam Bindingenergieswhatholdstheatom intheshell formed be of attraction bw positiveelectrons inthe nucleusandnegative intheshell K Shell 69.5 LShell 12 Mshell 3 Nshell 1 electrons from the tube currentinteract w one of the binding can happen at anylevel Once it gets knockedoff one fromnextshellmoves and fills the hole andthat'swhen electron photon isproduced only usefulphoton is onethathappens whentheshift happens at the shellelectronmoved to ionization photons are produced as a result of an electronshiftingshells Bremsstrahlung X breaking reaction make up majority ofthe primarybeam ray electrons fromtube currenttraveling acrossthe tube gets slowed downfromtheenergy from the nucleus 2 things that determineenergy level I when an electron interacts w the atom how close does it move towards the nucleus further away from nucleus lowerxray photons 2 When an electron interacts w the atom how much does it change direction more direction change higher Xray photons Kinetic to electromagnetic Filtration impactsemission spectrum absorbsfilters allthe lowenergy photons sothattheydon't hitthe pt inherent andadded filtration is bothmadeup of aluminium AI putting themtogether is calledtotal filtration absorbs longwavelength photons improves quality ofthebeam hardens thebeam effect onoutput higher qualitybeamlowerdoseto pt increased tech factors required Inherent filtration 3 locations glass envelope insulated oil in tubehousing glass window everytube is required to have5mm ofaluminuminherentfiltration Total filtrationrequired is based on tube capacity below 50kVp 5mm Al Oadded filtration 5070kVp 1.5mmAl 1.0ml added filtration above70kVp 2.5mmAl 2.0mi added filtration Added filtration additionalfiltrationsheets ofaluminumthatareplaced outsidetheglass window ofthetubehousin nominumum Compensating filter Wedge shaped filterusedonpartsthatdonothaveetualthicknessthroughoutexfeet t spine would putthe thicker part ofthewedge onthethinnestbody sothatthefilterabsor part photons to not be covered by darkness Entity 8 unt of current electrons travelinginthetube of x rayphotons MA s time MAS MAS of Xray photons Quality is kVp kilovoltagepeak aspeak voltage of thebeam accelerateselectrons acrossthetube highervoltage higher energy photonsandmore x ray photons Quality istheenergy of xrayphotonsQuantity isthe of X ray photons it TestQuestions 1 Atomic oftungsten 74 2As wavelength increases energy decreases frequency decreases 3 Characteristics xray photons are produced as aresult of electron shiftingshells 4Waveparticle dualitypertains to someforms of radiation onthe electromagnetic spectrum 5Inertia an object at restremains at rest 6Hertz frequency 7 Convection heattransferred through gas 8Electrons are accelerated as a result of KVP it emgn 11Applying anode heel effect for Tspine the cathodeshouldbe aligned to lower part 12Wavelength is indirectly proportional to energy andfrequency 13Effectivefocalspot pointed at the pt 14Smallanode angle improvesdetail 15Base ofrotating anode is made up of molybdenum 16Rotor is located inside the envelope 17Quantity verticalaxis on the spectrum 18Rotation of the anode prevents overheating 19 0.6mm bestrecorded detail 20 1.5mmfocalspotis large 21 Max amount of leakage 100MR hr 01meter 22now closetheelectrons aretothe nucleus impact energy levelfor Bremsstrahlung 23Anodeheeleffect is caused by anode's absorption of Xray photons 24 Primary beamexits through window 25Anode is the source of radiation 26 Wavelength Angstrom 27 Factors of Espectrum filtrationmas atomic kup 28Thermionic emission production of electrons 30Bremss electron slowsdown andchanges direction 32 effective focal spot size depends on anode angle tungsten electron 34igerfiaimeiiEEastierd.IE EE.ie iiiiiiiii i iiiiiiiiii.in l É ftpffYg en fffff ÉfnunffÉt nsfÉ Y 48Exitthroughthewindowusefulbeam 50Offfocusproduced anywhere butthefocalsp ftp.tp.mfeituftiiiniiiieentry protons and increased of protons 49 tffation mchargeeffect Xray emission spectrum graph toshowquantity andqualityenergylevel also shows characteristicandbremsstrah X axis is xray quality kev horizontal Y axis is Xray quantity MAS vertical 4factorskVpMAfiltration and atomic highermAhigherheightand of photons higherkvp higherheightcurveshiftstotherightandmorephotons Kevmaxenergy ofphotons 4 factors MA miliamperage showswhat's beingemittedfrom thetube changes the height but no shift to the curve KVp effects both heightandposition of the curve as kvp goes up of electrons go up and curve shifts to the right higherkvp gives higher energy betterquality photons Filtration Addedfiltrationhardensthebeampullsoutlowenergywhich decreasesthe amountofphotons butincreasingthequalit whenyouincrease filtrationcurveshiftslowerbuttotheright Targetmaterial atomic of thetargetmaterialaffects boththe quantityandquality highatomic produces higherenergy andmore electrons Tungsten74 attracts moreelectrons due to high atomic Factor change Quantity Quality CurrentMAS increase increase no change Voltagekvp increase increase increase increase increase TargetAtomic increase increase Filtration increase decrease  Primary Factors MASKVP anddistance MAs iii processing prime controllerofdensity andexposure is controls the of X rays produced mAs goes up thentubecurrentandquantity goesup increases density which darkens theimage Insufficientmas toolight underexposed image morex rays darker Excessive MAS overexposed image toodark less xrays lighter KVp kilomeans thousands prime controller of contrast highkvp low contrast contrast image w blackandwhiteonly lowKVP high contrast andno grey ishigh contrast of electrons intubecurrent ofXrays produced increasesenergy energy of Xrays andpenetrability increases boththedensity infilmandIRexposure indigital 15010rule appliesto Kup Ifyouleave mas thesame increase Kvpby 154 double density doubledarkening decrease Kvp by 15 half density lighter Example chest increase in effectonquantity effectonquality 8mas074kup 15 half dens MAs increase none 8mA 085Kupt yup increase increase 8mA 695Kupkta Distance decrease none density MaintainDensity 16MAS 675KVP 8mA 685KVP to maintain ifyouincreaseyourkupby1501 then 4MAS698kup cutthe MAS in half ifyoudecrease by151 then theMAs is doubled adjustment to technique reduces ptdose by704 andadjusts contrast Distance inverse square law more distance meansless intensityfurther awayyou are less photonsthe ptwillget 2 d 44intensity 5 d 49 intensity 4 d 116intensity Effie iftheyhavetoofewoftoomany electrons objects areelectrified deals w electrical charges that arestaticstationary notmoving Addition ofelectrons negativeelectrification Removal ofelectronspositive electrification Electrification by Friction 2 objects rubbedtogether oneloses electrons andonegains Efb.it tIargeYbfIfIiontouines an uncharged objectthenthe2ndobject gainsthe charge offirst if 1ˢᵗobject ispositivethen2ndobjectwillbe positive Electrification by induction shiftthatoccurs bw 2objectswithoutdirectcontact when an objectwith a charge is broughtnear aneutralobjectthentheelectronsinthe neutral objectmore if its negative charged theelectrons move tothefarside ifits positive electronsmovetothesideclosest tothecharged object whichwouldcreate apositive charge onthat infection mitientintiedneutia object depends on material and temperature Nonconducters Doesnot let them move when temperature increases conductivity decreases Conducters electrons move freely Semiconductorsallows someelectronstomove when temperature increases conductivity increases Superconductors allows electronstomovethe most best at low temperature Electric charges Charged objects all have electrical fields Positively chargedlines offorceextend out in all directions Negatively charged lines offorce travel toward the object Due to lines offorce electrons attract each other extends out goestowards Repulsion Attraction Laws of electrostatics 1Attraction andrepulsion opposites attractlikechargesrepeldueto electric fields 2 Coulomb's Law whenthecharge is doubletheforcewillbe strongerand whenthechargesare closer they are stron.GG nit for electrical charge Coulomb IC electrical charge of6.25.10s electrons 3 Electrical charges reside mainly on the externalsurfaces of conductorsMutualrepulsion sotheymove furthestaway fromeach other aspossible 4 concentration of charges greatestamount of charges are foundwhere thesevere curve is on an object