kVP Accuracy - Quality control in radiography

There are guidelines set by H.A.R.P. and S.C. 35 to ensure an appropriate range of kVp accuracy. H.A.R.P. sets the accuracy at ±8% while S.C. 35 ...   Qualitycontrolinradiography About ClusterOne HalfValueLayer EICalibration VisualInspection Film/ScreenContact GridAlignment CRErasure ClusterTwo LightFieldCongruencyTest TimerAccuracy kVpAccuracy LimitingSpatialResolution CRUniformity DR(QAP) ClusterThree Reproducibility ThresholdContrastDetailDetectabilityCR&DR CRDarkNoise Linearity Mammography Contact QUALITYCONTROLINRADIOGRAPHY kVPAccuracy 2/28/2015 0Comments   MICHELLEFERDERBAR1217500Kilovoltpeak(kVp)isatechnicalfactorsetbythetechnologistwhenperformingx-rays.Itspurposeistosetthepenetratingpowerofthex-raysorthequalityofthebeam.Thenumbersetisthehighestamountofenergythatanx-rayphotoncouldhaveleavingthetube.ItisimportantthatthekVpsettingreflectswhatisactuallycomingoutofthetubetoensurereproducibility.Thislabwasconductedinx-rayroom4andx-rayroom3,B114oftheInstituteofAppliedHealthSciencesontheMcMasterUniversityCampus.Figure1.ThesetupforthekVpaccuracytest.Theprocedurewasfairlysimple.WesettheSIDto70cmandcollimatedtotheentiretyofthesensor.Wetookthreeexposureseachat60kVp,81kVp,and102kVpat5mAs.WetookanotherthreeexposureseachattheaforementionedkVpsbutat16mAs.WeusedtheCobiaSmartx-raymetertodeterminethekVpvaluesinRoom4andadifferentmeterinroom3.Whenwetooktheseexposures,wewaitedroughly30secondsbetweeneachexposuretopreventtubeoverload.Table1.kVpreadingsandaveragesobtainedfromRoom3.kVpmAsValue1Value2Value3AveragekVpPercentageDifference60551.8351.5051.3551.56-14.07601651.3251.3551.2551.31-14.4881578.9379.1779.3579.15-2.28811679.1379.1979.1279.15-2.28102598.5498.0198.0698.20-3.731021699.5698.7998.6198.99-2.95Table2.kVpreadingsandaveragesobtainedfromRoom4.kVpmAskVp1kVp2kVp3AveragekVpPercentageDifference60560.0760.1760.2360.16+1.93601660.1560.1660.2260.18+1.9781580.9581.0180.9780.98+1.23811681.1481.1081.1181.12+1.401025101.6101.6101.7101.6-0.3610216101.9101.9101.8101.9-0.13ThereareguidelinessetbyH.A.R.P.andS.C.35toensureanappropriaterangeofkVpaccuracy.H.A.R.P.setstheaccuracyat±8%whileS.C.35setsitat±10%.Papp(2011)isthemoststrictwith±5%.Inroom4,allkVpsettingspass.Inroom3,60kVpat5mAsand60kVpat16mAsfailbyallstandards.SomepossiblereasonsforthisarethatthereaderwaslesssensitivetothislowerkVpsetting,theunithasfaultycircuitry,thehighvoltagetransformermaybemalfunctioning,theautotransformermayhaveanissue,orthesupplytothegeneratorisnotthegreatest(Stelmark,2010).ItisveryimportantthatkVpaccuracyismaintainedtoensurethatthedesiredtechniqueiscomingoutofthetube.SincekVpcontrolsbothx-raybeamqualityandquantity,havingtheincorrectkVpexitingthetubemayresultinfailingtofollowtheALARAprincipleandoverdosingourpatient.Thistestshouldbeperformedannually(Papp,2011). ReferencesHealthCanada.(2008). Safetycode35:Safetyproceduresfortheinstallation,useand      controlofx-rayequipmentinlargemedicalradiologicalfacilities.      Retrieved fromhttp://www.hc-sc.gc.ca.Papp,J.(2011).Qualitymanagementintheimagingsciences(4thed.).St.Louis,         Mo.:MosbyElsevier.ServiceOntario.(2011). HealingArtsRadiationProtectionAct.Retrieved from          http://www.e-laws.gov.on.ca/html/regs/english/elaws_regs_900543_e.htm.Stelmark,J.(2010).AppliedQualityManagement:kVpAccuracyandReproducibility.        Retrievedfromhttp://profstelmark.com/QA_new/report%20sample.pdf. 0Comments LeaveaReply. Michelleferderbar Asastudentradiographercurrentlyinher3rdyearatMohawk-McMasterMedicalRadiationSciencesprogram,MichellespentherfirstclinicalplacementatJuravinskiHospitalinHamilton,Ontario.There,shehadtheopportunitytoexperiencequalitycontrolroutinesdonebytheprofessionals.Sheisthrilledattheopportunitytolearnthereasonsandtheoriesbehindthem. Archives February2015 Categories All RSSFeed Poweredby Createyourownuniquewebsitewithcustomizabletemplates. GetStarted