Helical or Spiral CT - SPIE Digital Library

9.1 Introduction Helical CT (also called spiral CT) was introduced commercially in the late 1980s and early 1990s. Helical CT has expanded the traditional ... SignIn ViewCart Help EmailorUsername Forgotyourusername? Password Forgotyourpassword? Show Keepmesignedin Pleasewait... NoSPIEaccount?Createanaccount InstitutionalAccess:Signinwithyourinstitutionalcredentials TranslatorDisclaimer Youhaverequestedamachinetranslationofselectedcontentfromourdatabases.Thisfunctionalityisprovidedsolelyforyourconvenienceandisinnowayintendedtoreplacehumantranslation.NeitherSPIEnortheownersandpublishersofthecontentmake,andtheyexplicitlydisclaim,anyexpressorimpliedrepresentationsorwarrantiesofanykind,including,withoutlimitation,representationsandwarrantiesastothefunctionalityofthetranslationfeatureortheaccuracyorcompletenessofthetranslations. Translationsarenotretainedinoursystem.YouruseofthisfeatureandthetranslationsissubjecttoalluserestrictionscontainedintheTermsandConditionsofUseoftheSPIEwebsite. HelicalorSpiralCT Book:ComputedTomography:Principles,Design,Artifacts,andRecentAdvances,SecondEdition Author(s):JiangHsieh Published:2009 https://doi.org/10.1117/3.817303.ch9 ARTICLE DOWNLOADPDF SAVETOMYLIBRARY AccesstotherequestedcontentislimitedtoinstitutionsthathavepurchasedorsubscribetoSPIEeBooks. YouarereceivingthisnoticebecauseyourorganizationmaynothaveSPIEeBooksaccess.* *Shibboleth/OpenAthensusers─please signin toaccessyourinstitution'ssubscriptions. Toobtainthisitem,youmaypurchasethecompletebookinprintorelectronicformaton SPIE.org. MyLibrary Youcurrentlydonothaveanyfolderstosaveyourpaperto!Createanewfolderbelow. CreateNewFolder SAVE> Abstract 9.1Introduction HelicalCT(alsocalledspiralCT)wasintroducedcommerciallyinthelate1980sandearly1990s.HelicalCThasexpandedthetraditionalCTcapabilitybyenablingthescanofanentireorganinasinglebreath-hold.ItissafetostatethathelicalCTisoneofthekeystepsthatmovedCTfromaslice-orientedimagingmodalitytoanorgan-orientedmodality. ThedifferenceinthenamingconventionbetweenhelicalandspiralCTisduemainlytodifferentCTmanufacturers.Forallpracticalandtechnicalpurposes,thereisnodifferencebetweenthetwo.Toavoidconfusion,wewillusetheterm“helical”throughoutthischapter. 9.1.1Clinicalneeds Allpreviouschaptershavefocusedonasinglescanningprotocol:thestep-and-shootmode.Thisscanningprotocolcontainsbothadataacquisitionperiodandnon-data-acquisitionperiod.Duringthedataacquisitionperiod,thepatientremainsstationarywhilethex-raytubeanddetectorrotatesaboutthepatientataconstantspeed.Onceacompleteprojectiondatasetisacquiredfortheslice,thenon-data-acquisitionperiodstarts.Thex-raytubeisturnedoffandthepatientisindexedtothenextscanninglocation.FortypicalCTscanners,theminimumnon-data-acquisitionperiodisontheorderofsecondsasaresultofbothmechanicalandpatientconstraints.Themechanicalconstraintisduetothefactthatatypicalpatientweighsover45kg,andthepatienttablerequiresacertainamountoftimetomovealargemassfromonelocationtoanother.Thecauseofthepatientconstraintmaynotbeasobvious.Fromthelawofphysicsweknowthattomovearestingobjectoverashortdistance,firstwemustacceleratetheobjectuptoacertainspeedanddeceleratetheobjectwhenitisnearthetargetlocation.Sincethedistancebetweenadjacentscanninglocationsistypicallyafewmillimeters,theamountofaccelerationanddecelerationisfairlylarge.Ahumanbodyisnotrigid(theinternalorganscanmoveanddeform),sotheaccelerationanddecelerationwilllikelyinducemotioninthepatient.Asaresult,acertainamountoftimemustelapsetominimizemotionartifacts. Inthelate1980s,theCTscanspeedapproachedonesecondperrevolution. OnlineaccesstoSPIEeBooksislimitedtosubscribinginstitutions. CHAPTER9 DOWNLOADPDF SAVETOMYLIBRARY SHARE FolderName FolderDescription SAVE CITATIONS ExplorecitationsonLens.org Advertisement Advertisement KEYWORDS X-raycomputedtomography Dataacquisition X-rays Computedtomography Manufacturing Nomenclature Physics Scanners Sensors X-raydetectors ShowAllKeywords SubscribetoDigitalLibrary ReceiveEmailAlertsonNewlyReleasedTitles ErratumEmailAlertsnotifyyouwhenanarticlehasbeenupdatedorthepaperiswithdrawn. VisitMyAccounttomanageyouremailalerts. EmailorUsername Forgotyourusername? Password Forgotyourpassword? Show Keepmesignedin NoSPIEaccount?Createanaccount InstitutionalAccess:Signinwithyourinstitutionalcredentials Thealertsuccessfullysaved. VisitMyAccounttomanageyouremailalerts. CLOSE Thealertdidnotsuccessfullysave.Pleasetryagainlater. CLOSE PublicationEmailAlertsnotifyyouwhenanewvolumehasbeenpublished. ViewMyAccounttomanageyouremailalerts. SAVEALERT CONFERENCEPROCEEDINGS Papers Presentations Journals AdvancedPhotonics JournalofAppliedRemoteSensing JournalofAstronomicalTelescopes,Instruments,andSystems JournalofBiomedicalOptics JournalofElectronicImaging JournalofMedicalImaging JournalofMicro/Nanopatterning,Materials,andMetrology JournalofNanophotonics JournalofOpticalMicrosystems JournalofPhotonicsforEnergy Neurophotonics OpticalEngineering Ebooks Help| AdvancedSearch> Keywords/Phrases Keywords in AllFields Abstract AuthorName Affiliation DOI/ISSN/ISBN Figure&TableCaptions Keywords Title VolumeTitle Remove AND OR NOT in AllFields Abstract AuthorName Affiliation DOI/ISSN/ISBN Figure&TableCaptions Keywords Title VolumeTitle Remove AND OR NOT in AllFields Abstract AuthorName Affiliation DOI/ISSN/ISBN Figure&TableCaptions Keywords Title VolumeTitle Remove +Addanotherfield SearchIn: Proceedings Volume Journals+ Volume Issue Page AdvancedPhotonics JournalofAppliedRemoteSensing JournalofAstronomicalTelescopesInstrumentsandSystems JournalofBiomedicalOptics JournalofElectronicImaging JournalofMedicalImaging JournalofMicro/Nanolithography,MEMS,andMOEMS JournalofNanophotonics JournalofPhotonicsforEnergy Neurophotonics OpticalEngineering SPIEReviews eBooks+ FieldGuideSeries PressMonograph Spotlight TutorialText OtherPress PublicationYears Range SingleYear ClearForm