kVp Accuracy - Welcome - cluster 1

Even small variations in kVp changes the penetration power and the quantity of the beam causing loss of optical density and contrast. Test. In this lab a kVp ... Welcome kVpAccuracy Introduction KilovoltPeak(kVp)isthecomponentthatcontrolsthequalityofthex-raybeamproduced. Itisalsowhatcontrolsthecontrastorgrayscaleintheproducedx-rayfilm.ThehigherthekVP,thelowerthecontrast. WhenthekVissetonthecontrolconsole,themaximumpotentialacrossthetubethatwillbeachievedisthenumberthathasbeenselected(Clark,2015).kVpcontrolsquantityofthebeamaswell.Anincreaseof15%kVphasthesameeffectasdoublingthemAsintermsoftheexposure.CorrectkVpselectionandoutputiscriticalforgettingtherightqualityofdiagnosticimages,thatiswhycorrectkVpcalibrationisacriticalmaintenanceofthex-raysystems.EvensmallvariationsinkVpchangesthepenetrationpowerandthequantityofthebeamcausinglossofopticaldensityandcontrast. Test InthislabakVpmeter,leadsheet,andanx-raysuitewereused. ThekVpmeterwasplacedontheleadapronandthex-raytubewascenteredtothekVpmetersensorat70cmSID.Theentiresensorsurfacewascoveredwiththechosencollimation.ThekVpmeterwasexposedanreadingsforrecordedthreetimeswiththreedifferentkVp (60,81,and102)andtwodifferentmAs (5,15)settingsinthetwodifferentrooms(3,and5). kVpmeter Results   Room3 NominalkVp mAs MeasuredkVp1 MeasuredkVp2 MeasuredkVp3 AvaragekVp %Deviation 60 5 60.6 60.4 60.5 60.50 0.83 60 15 60.6 60.6 60.6 60.60 1.00 81 5 83.9 83.9 83.9 83.90 3.58 81 15 83.6 83.6 83.6 83.60 3.21 102 5 105.3 105.3 105.3 105.30 3.24 102 15 105.0 105.0 105.0 105.00 2.94     Room5 NominalkVp mAs MeasuredkVp1 MeasuredkVp2 MeasuredkVp3 AvaragekVp %Deviation 60 5 58.8 58.5 58.6 58.63 2.28 60 15 59.3 59.4 59.4 59.37 1.67 81 5 82.1 82.1 82.1 82.10 1.36 81 15 81.9 81.9 81.9 81.90 1.12 102 5 102.8 102.8 102.7 102.77 0.78 102 15 102.3 102.3 102.3 102.30 0.29   Standards AccordingtoHARP,thedeviationrangeofthemwasuredkVpfromtheselectedmustbewithin ±8%.SC35requirestherangetobewithin ±10%.TherangereferredtoinPapp(2015)is±5%.Whenwelookatthedeviationvaluesforbothrooms,notevenonevalueiscloseto5.00%whichisthemostminimumrequirementstandard(Papp,2015).Bothx-rayunitsinroomthreeandfivemeetalltherequirementsforkVpaccuracy. Conclusion Indiagnosticradiology,thetubevoltagepeakkilovoltage(kVp)isoneofthemostimportantparametersaffectingbothradiationexposureandimagecontrast.So,anaccuratekVpmeterisnecessarytocontrolkVpinthemedicalradiographypracticewiththeoveralluncertaintylessthan±5%(DepartmentofNuclearEngineeringandManagement,SchoolofEngineering,TheUniversityofTokyo,2011). Iffluctuationsmorethan±10%occurringwithawellcalibratedkVpmeteronaunit,thismightindicateamajorproblemwithintheunit.Fluctuationsinincomingpoweroutlettotheprimarysideofthehighvoltagetransformermightalsobethecauseaswellaslinevoltagecompensator.Kvpisthemainfactorthateffectscontrast,askVpincreasesscatteralsoincreases.Fluctuationsbeyondacceptablelimitswillaltertheimagequality.Eachx-rayunitshouldgothroughqualitycontrolonregularbasestoprovidebestpossiblequalityimageswithleastdosestopatients. References Clark,K.(2015).KvPandmAsDefinitions.Elcamino.edu.Retrieved22February2015,from      http://www.elcamino.edu/faculty/kclark/RTA%20Handouts/kvp_mas_define.docDepartmentofNuclearEngineeringandManagement,SchoolofEngineering,TheUniversityofTokyo.(2011,March29).      CalibrationofKVpmeterusedinqualitycontroltestsofdiagnosti...-PubMed-NCBI.Retrievedfrom       http://www.ncbi.nlm.nih.gov/pubmed/21447505Papp,J.(2015).Qualitymanagementintheimagingsciences(5thed.).St.Louis,MO:ElsevierMosby. Poweredby Createyourownuniquewebsitewithcustomizabletemplates. GetStarted