SirGodfreyHounsfield,whodiedonAugust12aged84,ledtheteamwhichdevelopedBritain''''sfirstbigsolid-statecomputerbeforeinventingthecomputerisedaxialtomography(CAT)scannerforuseinclinicaldiagnosis;inrecognitionofthislatterachievementhewasawardedthe1979NobelPrizeforPhysiologyorMedicine.

HounsfieldconceivedtheideaforaCATscannerin1967duringaweekendrambleinthecountry.Initiallyithadnothingtodowithmedicine,butwassimply"arealisationthatyoucoulddeterminewhatwasinaboxbytakingreadingsatallanglesthroughit".

OnhisreturntoEMI''''sresearchlaboratoriesatHayes,inMiddlesex,hebeganworkingonadevicethatcouldprocesshundredsofX-raybeamstoobtainathree-dimensionaldisplayoftheinsideofalivingorganism.

CombiningcomputerandX-raytechnology,andpractising"onabrainofacowmycolleaguegotfromakosherhouseontheothersideofLondon"(hesubmittedhisownheadforthefirsthumantrials),by1972Hounsfieldhadevolvedamachinethatcouldproducedetailedimagesofcross-sectionsofthebraininfourandahalfminutes.

Introducedin1973,earlyCATscannerswereusedtoovercomeobstaclesinthediagnosisofdiseasesofthebrain,andHounsfieldsubsequentlymodifiedhismachinetoenableittoscanthewholebody.

UnknowntoHounsfield,aSouthAfricannuclearphysicist,AllanCormack,hadworkedonessentiallythesameproblemsofCAT,andinapaperpublishedin1957hadsuggestedareconstructiontechniquecalledtheRadontransform.AlthoughCormack''''sworkwasnotwidelycirculated,andheandHounsfielddidnotcollaborateorevenmeet,in1979bothmensharedtheNobelPrizeinPhysiologyorMedicineforthedevelopmentofcomputerisedtomography.

TheinventionoftheCATscannerwasaremarkableachievement,notleastbecauseofthecomplexalgebraiccalculationsinvolvedinthecomputerprogramming.OtherresearchteamswithlargerresourcesthanEMIhadalreadydismissedsuchadeviceasimpossibletodevelop,andoneprominentBritishscientistremarkedthatHounsfield''''smachineused"mathematicsIwouldn''''tpretendtounderstandnoworatanystageofmycareer".

YetHounsfieldhadneverbeentouniversityandwaslargelyself-taught.

GodfreyNewboldHounsfield,theyoungestoffivechildrenofafarmernearNewarkinNottinghamshire,wasbornonAugust281919.Atanearlyagehebecameintriguedbythefarm''''smechanicalandelectricalmachinery,andbytheageof11hehadbeguntoexperiment,constructingelectricalrecordingmachinesandlaunchinghimselfoffthetopofhaystackswithahome-madeglider.

AtMagnusGrammarSchoolinNewark,heconfessedtoresponding"onlytophysicsandmathematicswithanyeaseandmoderateenthusiasm".ButaswithsomanyofBritain''''sgreatpost-warscientists,hisopportunitycamewiththeoutbreakoftheSecondWorldWar.

HounsfieldjoinedtheRAFasavolunteerreservist,hopingtobecomeinvolvedinradio.HavingperusedsomeRAFbooksonradiomechanics,hesatatestandwasamazedwhenhewasthentakenonasaradar-mechanicinstructorandmovedtothethenRAF-occupiedRoyalCollegeofScienceinSouthKensington,andlatertoCranwellRadarSchool.

There,inhissparetime,hepassedtheCityandGuildsexaminationinRadioCommunications.In1945hewasawardedtheRAF''''sCertificateofMerit.HisworkimpressedAirVice-MarshalJRCassidy,whowasresponsibleforobtainingagrantforHounsfieldafterthewarwhichenabledhimtoattendFaradayHouseElectricalEngineeringCollegeinLondon,wherehereceivedadiploma.

In1951HounsfieldjoinedtheresearchstaffofEMIatHayes.Forawhileheworkedonradarandguidedweapons,thenranasmalldesignlaboratory,wherehesoonbecamefascinatedbytheemergingfieldofcomputers.Startinginabout1958,heledadesignteamwhichbuiltthefirstall-transistorcomputertobeconstructedinBritain,theEMIDEC1100.

Inthosedaysthetransistorwasarelativelyslowdevice-muchslowerthanvalves,whichwerethenusedinmostcomputers.However,Hounsfieldwasabletoovercomethisproblembydrivingthetransistorwithamagneticcore.Thisincreasedthespeedofthemachinesothatitcomparedwiththatofvalvecomputersandbroughtabouttheuseoftransistorsincomputingearlierthanhadbeenanticipated.

Whenthisworkfinished,HounsfieldtransferredtoEMICentralResearchLaboratories,alsoatHayes,wherehebeganhisworkonCATscanners.Thiswork,andthedevelopmentofprogressivelymoresophisticatedprototypesofbrainandwholebodyscanners,kepthimoccupieduntil1976.

Heremainedresponsibleforlong-termthinkingaboutmedicalsystemsatEMI''''sresearchlaboratorieswhileothersmanagedtheResearchandDevelopmenteffortsupportinghisscanners.InhislateryearswithEMI,hebroadenedhisinterestsintorelatedfieldsofdiagnosticimaging,suchasnuclearmagneticresonance.

Afterhisofficialretirementin1986,HounsfieldcontinuedtoworkasaconsultantforEMI,andalsotovarioushospitals,includingtheNationalHeartandChestHospitals,Chelsea,theNationalHeartHospitalandtheBromptonHospital.

Truetothearchetypeoftheshy,retiringbachelorboffin,Hounsfieldfoundthepublicinterestinhisinvention"mostembarrassing".Hewonnumerousawardsandhonours(35inthe1970salone),amongthemelectiontotheRoyalSociety,arareaccoladeforsomeonewhodidnotpossessauniversitydegree.

Afrugalman,HounsfieldspentverylittleonhimselfandalwaysrefusedEMI''''soffertolethimtakeasabbatical.Whenpresentedwiththe1972MacRobertawardfromtheCouncilofEngineeringInstitutions,hesaidhewouldkeephis￡25,000prizeinreserve"incasesomenewresearchideaturnsup,inwhichcaseIcanploughitback".Hedid,however,spendalittleofhisNobelprizemoneyonfittingouttheliving-roomofhissmallsemi-detachedhouseinMiddlesexwithscientificequipment.

Apartfromhiswork,Hounsfield''''sgreatestpleasureswerewalkinginthemountainsandleadingcountryrambles.Heenjoyedmusicandplayedthepiano"inaself-taughtway".Incompany,heconfessedtoenjoying"lively,way-outdiscussions".

OnthedayhewontheNobelprizein1979,Hounsfieldhadsomehome-spunwordsofadviceforallwould-beNobelprizewinners:"Don''''tworrytoomuchifyoudon''''tpassexams,solongasyoufeelyouhaveunderstoodthesubject.It''''samazingwhatyoucangetbytheabilitytoreasonthingsoutbyconventionalmethods,gettingdowntothebasicsofwhatishappening."

GodfreyHounsfieldwasappointedCBEin1976andknightedin1981.HewaselectedtoafellowshipoftheRoyalSocietyin1975.

Hewasunmarried.