Designation:E1441−11StandardGuideforComputedTomography(CT)Imaging1ThisstandardisissuedunderthefixeddesignationE1441;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope*1.1Computedtomography(CT)isaradiographicmethodthatprovidesanidealexaminationtechniquewhenevertheprimarygoalistolocateandsizeplanarandvolumetricdetailinthreedimensions.Becauseoftherelativelygoodpenetra-bilityofX-rays,aswellasthesensitivityofabsorptioncrosssectionstoatomicchemistry,CTpermitsthenondestructivephysicaland,toalimitedextent,chemicalcharacterizationoftheinternalstructureofmaterials.Also,sincethemethodisX-raybased,itappliesequallywelltometallicandnon-metallicspecimens,solidandfibrousmaterials,andsmoothandirregularlysurfacedobjects.Whenusedinconjunctionwithothernondestructiveevaluation(NDE)methods,suchasultrasound,CTdatacanprovideevaluationsofmaterialinteg-ritythatcannotcurrentlybeprovidednondestructivelybyanyothermeans.1.2ThisguideisintendedtosatisfytwogeneralneedsforusersofindustrialCTequipment:(1)theneedforatutorialguideaddressingthegeneralprinciplesofX-rayCTastheyapplytoindustrialimaging;and(2)theneedforaconsistentsetofCTperformanceparameterdefinitions,includinghowtheseperformanceparametersrelatetoCTsystemspecifications.Potentialusersandbuyers,aswellasexperiencedCTinspectors,willfindthisguideausefulsourceofinformationfordeterminingthesuitabilityofCTforparticularexaminationproblems,forpredictingCTsystemperformanceinnewsituations,andfordevelopingandprescribingnewscanpro-cedures.1.3Thisguidedoesnotspecifytestobjectsandtestproce-duresforcomparingtherelativeperformanceofdifferentCTsystems;nordoesittreatCTinspectiontechniques,suchasthebestselectionofscanparameters,thepreferredimplementationofscanprocedures,theana...
