Basics of X-ray Physics - X-ray production - Radiology ...

The X-ray tube ... X-rays are generated via interactions of the accelerated electrons with electrons of tungsten nuclei within the tube anode. There are two types ... Home»Tutorials»X-rayPhysics»X-rayproduction TutorialMenu Tutorialintroduction X-rayproduction TheX-raybeam Tissuedensities X-raysafety Tutorialconclusion«PreviousTutorialsNext»BasicsofX-rayPhysics X-rayproductionKeypointsX-raysareproducedbyinteractionofacceleratedelectronswithtungstennucleiwithinthetubeanodeTwotypesofradiationaregenerated:characteristicradiationandbremsstrahlung(braking)radiationChangingtheX-raymachinecurrentorvoltagesettingsaltersthepropertiesoftheX-raybeamX-raysareproducedwithintheX-raymachine,alsoknownasanX-raytube.Noexternalradioactivematerialisinvolved.RadiographerscanchangethecurrentandvoltagesettingsontheX-raymachineinordertomanipulatethepropertiesoftheX-raybeamproduced.DifferentX-raybeamspectraareappliedtodifferentbodyparts.TheX-raytubeHoveron/offimagetoshow/hidefindingsTapon/offimagetoshow/hidefindings ClickimagetoalignwithtopofpageTheX-raytubeAsmallincreaseinthefilamentvoltage(1)resultsinalargeincreaseintubecurrent(2),whichaccelerateshighspeedelectronsfromtheveryhightemperaturefilamentnegativecathode(3)withinavacuum,towardsapositivetungstentargetanode(4).Thisanoderotatestodissipateheatgenerated.X-raysaregeneratedwithinthetungstenanodeandanX-raybeam(5)isdirectedtowardsthepatient.X-raysaregeneratedviainteractionsoftheacceleratedelectronswithelectronsoftungstennucleiwithinthetubeanode.TherearetwotypesofX-raygenerated:characteristicradiationandbremsstrahlungradiation.CharacteristicX-raygenerationHoveron/offimagetoshow/hidefindingsTapon/offimagetoshow/hidefindings ClickimagetoalignwithtopofpageCharacteristicX-raygenerationWhenahighenergyelectron(1)collideswithaninnershellelectron(2)bothareejectedfromthetungstenatomleavinga'hole'intheinnerlayer.Thisisfilledbyanoutershellelectron(3)withalossofenergyemittedasanX-rayphoton(4).Bremsstrahlung/BrakingX-raygenerationHoveron/offimagetoshow/hidefindingsTapon/offimagetoshow/hidefindings ClickimagetoalignwithtopofpageBremsstrahlung/BrakingX-raygenerationWhenanelectronpassesnearthenucleusitisslowedanditspathisdeflected.EnergylostisemittedasabremsstrahlungX-rayphoton.Bremsstrahlung=BrakingradiationApproximately80%ofthepopulationofX-rayswithintheX-raybeamconsistsofX-raysgeneratedinthisway.TheX-rayspectrumHoveron/offimagetoshow/hidefindingsTapon/offimagetoshow/hidefindings ClickimagetoalignwithtopofpageTheX-rayspectrumAsaresultofcharacteristicandbremsstrahlungradiationgenerationaspectrumofX-rayenergyisproducedwithintheX-raybeam.ThisspectrumcanbemanipulatedbychangingtheX-raytubecurrentorvoltagesettings,orbyaddingfilterstoselectoutlowenergyX-rays.InthesewaysradiographersareabletoapplydifferentspectraofX-raybeamstodifferentbodyparts.«PreviousTopNext» Pageauthor: DrGrahamLloyd-JonesBAMBBSMRCPFRCR-ConsultantRadiologist- SalisburyNHSFoundationTrustUK (Readbio) Lastreviewed: February2016