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Contents Introduction 1 1.AbouttheRadiationEfectsResearchFoundation 2 2.Yield(energy)ofA-bombsdroppedonHiroshima andnagasaki 4 3.Whatisradiation? 6 4.RadiationdosesinHiroshimaandNagasaki 8 5.Efectsofradiationonhumans 10 5.1.Acute(early)efects 10 5.2.Lateefects 11 Summary 11 Distinguishingradiation-relateddiseases 11 Deathsduetocancer 12 Cancerdevelopment 13 Variationdependingonageatthetimeofexposure 15 Noncancerdiseases 15 Efectsofprenatal(inutero)exposure 15 EfectsonthechildrenofA-bombsurvivors 16 6.Publicationofresearchfindings 17 7.Internationalcolaborationsandourhopes 17 Appendix1.CharacterizationoftheRERFstudypopulations 19 Appendix2.InformationrelatedtoA-bombsandradiation 20 Appendix3.Glosary 21 Appendix4.IntroductiontotheRERFdepartments 24
Introduction TheRadiationEfectsResearchFoundation(RERF)waspreceded bytheatomicbombcasualtycommission(abcc),whichwas establishedin1947andreorganizedintothepresent-dayjointu.s.-japan researchorganizationin1975,andthusthestudyofa-bombsurvivors hascontinuedformorethan60years.continuingthestudythisfar wouldnothavebeenpossiblewithoutthesteadfastfinancialsupportof thegovernmentsofjapanandtheunitedstates,cooperationofthe survivors,andsupportfrom thelocalcommunities,towhom weextend ourdeepestgratitude. Therearenootherepidemiologicstudiesofhealthandlongevityon apopulationofmorethan120,000individualsthathavecontinuedfor morethan60years.nevertheless,theentiretyoftheefectsofa-bomb radiationonhumanhealthhasnotbeenfulyelucidated.approximately 40% ofala-bombsurvivorsremainalive.amonga-bombsurvivors whowere20yearsoldoryoungeratthetimeofthebombings, however,morethan70% arestilliving,andthusfutureresearchis crucial.withrerf smissionetchedfirmlyinmind,weresolveto makefurtherefortstocontributetothehealthandwelfareoftheabombsurvivors,andtomeettheneedsoftheglobalcommunityinterms ofradiation-relatedmedicaltreatmentandsafetymeasures. Wehavepreparedthisbookletinhopesthatitwilaidthereaderin understandingourfoundation sactivities.wewelcomeyourcomments andsuggestions. May 2015 RadiationEfectsResearchFoundation 1
1.AbouttheRadiationEfectsResearchFoundation Purposeofendowment TheRadiationEfectsResearchFoundation(hereafterabbreviatedas RERF )wasinauguratedin1975asanonprofitorganizationaccordingto anagreementbetweenthegovernmentsofjapanandtheunitedstates.the missionofrerfisclearlydefined: toconductresearchandstudiesfor peacefulpurposesonmedicalefectsofradiationandasociateddiseasesin humans,withaview tocontributingtomaintenanceofthehealthand welfareoftheatomicbombsurvivorsandtoenhancementofthehealthof alhumankind. RERFisalsouniqueinthatJapanandtheU.S.jointly manageitsbudget,personnel,andothermaters.article40ofjapan slaw ConcerningSupportfortheAtomicBomb Exposed(AtomicBomb SurvivorsSupportLaw * )prescribestheobligationofthejapanese governmenttopromotesuchresearchandstudiesandprovidefunding. ImportantresearchtasksatRERFincludeestimatingthedosesof radiationexposureamonga-bombsurvivorsandanalyzingtheefectsof exposureonhumanhealth.anextensiveinterviewsurveywasconductedin the1950s,basedonwhichrecordswerecompiledforeacha-bomb survivor.theserecordsconcernedlocationandstructureofthebuildingthe survivormayhavebeeninatthetimeofthebombing.basedonthese records,radiationdoseswerecalculatedformostofthea-bombsurvivors. Ourmissionistousethisinformationtodocumentindetail,forposterity, how thea-bombingsandtheirradiationafecteda-bombsurvivors. Furthermore,theresultsofalstudiesaremadepublic,andinadditionto contributiontothewelfareofa-bombsurvivors,theseresultshave significantlycontributedtotheestablishmentinternationalyofdoselimits forradiationprotectionpurposes. Alongwithourhopethatneveragainshouldsuchdevastationfrom nuclearweaponsoccur,wemustnotforgetthatthenoblesacrificeofabombsurvivorscontributestoprotectingthesafety,intermsofradiation exposure,ofmanypersonsthroughouttheworld. 2
History ThepredecesororganizationtoRERFwastheAtomicBombCasualty Commision(ABCC).ABCCwasestablishedaftertheendofWorldWarI (inhiroshimain1947, 1 andinnagasakiin1948)bytheu.s.national AcademyofSciences(aprivatescientificorganization),withfundingfrom theu.s.government(atomicenergycommission).itwasjoinedin1948 bythejapanesenationalinstituteofhealth,partoftheministryofhealth andwelfare,andstudieswereconductedona-bombsurvivorswithina frameworkofbinationalcolaboration.inpractice,however,abcchadthe initiative,andtheu.s.sideboremostoftheexpenses. ABCCwasestablishedtodeterminehow,overthelongterm,exposure toradiationafectedthehealthofa-bombsurvivors.atthattime,japanwas occupiedbythea liedforces.manypeoplewerecriticaloftheunited States,whichhaddroppedthebombs,forstudyingtheA-bombsurvivors, whowerethevictimsofthebombings,andobjectedtothesestudies. 2 We whocontinuetheprogramsbegunbyabccregretanymisfortuneor unhappinesstheearly studiescaused thesurvivors.despitethese circumstances,manya-bombsurvivorscooperatedintheabccstudies. Becauseoftheircooperation,thelong-term studiesgotoftoagoodstart andcontinuesuccesfulytothisday. TheresultsofearlyABCCstudieswerereportedtotheJapanese MinistryofHealthandWelfare,andtheyservedasthebasisforenactment ofthea-bombsurvivorsmedicaltreatmentlaw * in1957. (*DescribedintheGlosarysectionattheendofthebooklet) Notes:1.SomepeopleasertthatABCCdemolishedamilitarycemeterytoconstruct theresearchlaboratoryonhijiyamainthecityofhiroshimain1950. However,asmentionedinthe ShortHistoryoftheMilitaryCemeteryon Hijiyama, thetruthisthat, demolitionwasbasedona1944agreement (oneyearbeforetheendofthewar)betweenthemilitaryandmunicipal authoritiesthatalgravemarkersweretoberemovedfortheconstruction ofajointgravemarker,underwhichalthewardeadinvolvedwouldbe enshrined. Reportedly,themilitaryandmunicipalauthoritiesintendedto usethesitetoconstructanantiaircraftgunbase. 2.Manyoftheresearchersinvolvedinconductingtheearlystudies understoodthecriticism andfeltcompassion,andhopedtoelucidate radiation sefectsforthesakeofthesurvivors. 3
2.Yield(energy)ofA-bombsdroppedonHiroshimaandNagasaki Theyieldsofenergygeneratedbytheatomicbombsdroppedon HiroshimaandNagasakiarethoughttohavebeenequivalentto16,000tons and21,000tons,respectively,oftnt(trinitrotoluene,explosiveusedin dynamite).a yieldofsuchmagnitudeisunimaginablefrom asingle conventionalbomb.however,somehydrogenbombs(i.e.,bombsinwhich theenergyofthea-bombisusedtoignitenuclearfusion * ofhydrogen atoms,asoccursinthesun)withayieldofmorethanonemiliontons(1 megaton)oftnt havesincebeenproducedbytheu.s.andformer U.S.S.R.ThebombtestedbytheU.S.intheBikiniatolin1954,whenthe fishingboatluckydragonfivewasexposedtotheso-caled ashesof death, wasreportedtohavehadayieldashighas15megatons. TheenergyoftheA-bombswasgeneratedbynuclearfission. * About 50% oftheenergywasreleasedasblast,35% asheat,and15% asradiation. Theblastandheatraysafectedareaswithinaradiusof4 5km from the hypocenter,butlitleradiationseemstohavereachedbeyond2.5km in Hiroshimaand3km innagasaki(figures1and2).radiationdose increasedwithproximitytothehypocenterbutvariedbecauseofshielding * providedbybuildings,terain,andthelike.sincethebombsdetonatedin theairatheightsof503and600metersinnagasakiandhiroshima, respectively,radioactivecontaminationonthegroundwasminimal(ifthe bombshaddetonatedontheground,contaminationcouldhaverenderedthe areasuninhabitable). ExposuretoA-bombradiationcanbeclassifiedintoprimaryexposure (mainlytogammaraysandneutrons)andexposuretoresidualradiation. * Residualradiationconsistsofradiationinducedbyneutronsandradioactive faloutcontainedinblackrain.thelevelsofinducedradiationwerehighest nearthehypocenters,butdecreasedrapidlywithdistancefrom the hypocentersandtimeafterthea-bombings.thelevelsofradioactivefalout werehighestinthekoiandtakasudistrictsinhiroshimaandinthe NishiyamadistrictinNagasaki. 4
Figure1.Distributionofenergyreleasedfrom theatomicbombs(%)and distanceatained Figure2.Areasincineratedbytheatomicbombsandareaswithhouses destroyedbythebombs 5
3.Whatisradiation? Radiationcanbethoughtofas transmissionofenergythroughspace (accordingtodr.soheikondo,professoremeritusofosakauniversity). Specificaly,radiationcompriseselectromagneticwaves * orparticle radiationwithkineticenergy,whichtypicalyrefertoxrays,gammarays, betaparticles(figure3),alphaparticles,andneutrons. TheXraywasdiscoveredin1895byDr.Wilhelm ConradRoentgen, whoobservedthatastrangelightwasemitedwhenhigh-speedelectrons colidedagainstmetal.anxrayhasthesamepropertiesasordinarylight (i.e.,electromagneticwaves).however,thex rayhasahigherenergy (shorterwavelength)andiscapableofpasingthroughsubstances.whenit pasesthroughthehumanbody,itcausesvariousinjuriestocels. Thegammarayisalsoanelectromagneticwavewiththesame properties.thediferenceistheprocessofitsgeneration;itisreleasedas extraenergywhenatomicnucleidecay.a-bombradiationiscomposed mostlyofgammarays. Together,alphaparticles,betaparticles,andneutronsarecaledparticle radiation.notelectromagneticwaves,theyareparticleswithhighenergy (i.e.,velocity).amongthecosmicrays * thatoriginateinthecosmosare particlerayswithsomuchenergythattheypasrightthroughtheearth. Theabilitytoreleaseradiationiscaled radioactivity, andmaterials havingsuchabilityarecaled radioactivesubstances. 6
Figure3.Xrayshavethesamepropertiesasgammarays(theybothbehave aselectromagneticwaves),althoughtheyareproduceddiferently. Radiationdose Theamountofradiationabsorbedbythebody(absorbeddose)is expressedinunitsofgray * (Gy).Miligray(mGy)isalsoused.One mgyequals0.001gy. Diferenttypesofradiationanddiferentsitesofexposureinthe bodyproducediferenthealthefects,evenwhentheradiationdoseis thesame.unitsofradiationbasedonthisideaareexpressedin sievert * (Sv).Onemilisievert(mSv)equals0.001Sv. BecauseA-bombradiationconsistedofmainlygammaraysbut alsoasmalfractionofneutrons,weuse weighteddose, asum of gamma-raydoseand10timestheneutrondoseingy. Radiationindailylife Aslongasonelivessomewhereonearth,exposureto natural radiation isagiven.theannualdoseofexposuretothisradiation averages2.4msv(0.2msvfrom one sbody,0.5msvfrom theground, 0.4mSvfrom space,and1.3msvfrom mid-airradon.forthose workingoninternationalairflights,whospendincreasedhoursathigh altitudes,annualexposuretocosmicradiationincreasestoabout 2mSv). 7
4.RadiationdosesinHiroshimaandNagasaki Figure4showstheassociationbetweendistancefrom thehypocenter andairdoseinhiroshimaandnagasaki.airdosemeanstheradiationdose intheairirespectiveofshieldingbyterainorstructures.inthecaseofabombexposureinsideanaveragejapanesehouse,abouthalfoftheradiation dosewasabsorbedbythehouse.thatis,theradiationdoseinsidesucha housewasabout1/2oftheairdose(dosereceivedoutdoorswithout shielding). Radiationdosefrom theatomicbombingsdecreasedbyaboutone-half every200m from thehypocenter.thecloserasurvivorwastothe hypocenter,thegreatertheefectswerefrom theblastandthermalraysas welasfrom radiation.itisnow understoodthatburnsexacerbatedthe detrimentalefectsofradiationonthebody. Figure4.Distancefrom thehypocenterandairdose(withoutshielding) accordingtods02(dosimetrysystem 2002 * ) 100 10 Gamma rays Hiroshima Nagasaki Air dose (Gy) 1 01 0.1 0.01 Neutrons 0.001 0.0001 05 0.5 10 1.0 15 1.5 20 2.0 25 2.5 Distance from the hypocenter (km) 8
Methodsofestimatingradiationdose Inadditiontotheradiationdosimetrysystem (curently,ds02),one method,inusesincethe1960s,studieschromosomes.oneccof bloodcontainsafewmilionlymphocytes(akindofwhitebloodcel). When cels startdividing afterbeing cultured fortwo days, chromosomes can be observed. Microscopic examination of abnormalitiesthatoccurinthechromosomesrevealstheapproximate amountofradiationtowhichindividualswereexposed(figure5). Itisalsopossibletoestimateradiationdosebyusingtheelectron spinresonance(esr)methodonextracted-toothenamel. Figure5.Totheleftisadividingcelwithtwoabnormalities,asindicatedby thearows.totherightisanalignmentofthesamechromosomes intheorderoftheirsize.abnormalchromosomeswereproducedby anexchangebetweensegmentsoftheno.2chromosomeandthe No.14chromosome(arows). 9
5.Efectsofradiationonhumans 5.1.Acute(early)efects Theefectsofradiationonhumanhealthvarydependingontheamount ofradiationreceived.whole-bodyexposureto10gyormoreoverashort periodoftimewouldundoubtedlycauselossoflifeevenwithcurent medicaltechnology.thisdosecorespondstoexposuretotheatomicbomb withoutshieldingat0.8km from thehypocenterinhiroshima(seefigure 4).Theradiationdoseatwhichabouthalfofalexposeddiedwithin60 daysisconsideredtobeabout3gyinhiroshima.thiscorespondstodoses receivedbythoseexposedtothebombinsidestandardjapanesehouses about1km from thehypocenters.acutesymptomssuchasnauseaand vomitingwereobservedamongabout10% ofthoseexposedto1gy. Amongthoseexposedto0.5Gy,decreasedlymphocytecountsinblood wereobserved. At2km ormorefrom thehypocenter,radiationdoseintheair decreasedto0.1gyorles,andacuteefectswerenolongerobserved.at3 km ormorefrom thehypocenter,theairdosedecreasedto0.002gy(2 mgy)orless.thisradiationdoseinstantaneouslyreceivedisequivalentto thecumulativenaturalradiationdosetowhichpeoplearetypicalyexposed overthecourseofayear(about0.002sv). Themaximum radiationdosesreceivedfrom inducedradiation * by thosewhoenteredtheexposedcitiesafterthebombingsareestimatedto havebeenabout0.8gyforhiroshimaand0.3 0.4GyforNagasaki, assumingthatthoseexposedtoinducedradiationwerepresentatthe hypocenterforanextendedperiod(indefinitely)sinceimmediatelyafterthe bombing.themaximum dosesfrom radioactivefaloutareestimatedto havebeen0.01 0.03GyintheKoiandTakasuareasofHiroshima,and 0.2 0.4GyintheNishiyamaareaofNagasaki. 10
5.2.Lateefects 5.2.1.Summary Severalyearsafterthewar,radiationcataract * wasfoundtohave increasedamonga-bombsurvivors(unlikesenilecataract,radiationcataract isgeneralynotprogressiveandfewpeoplelosetheireyesight).later,the numberofleukemiaandothercancerdeathsduetoradiationexposure increased.theleukemiaratereacheditspeak5 10yearsafterA-bomb radiationexposure,anddecreasedthereafter,butsomemarginalefectseems toremainevennow.ittookabout20years,ontheotherhand,forthe increaseofcancerssuchasthoseofthestomachandlungtobecome apparent.(thereasonsforsuchadiferencearenotclearlyunderstood.see Figure6.) Figure6.Excessdeathsfrom leukemiaandcancerduetoradiationexposure comparedwithnon-exposedcases(bynumberofyearsaftera-bomb radiationexposure)(nottoscale) f deaths ear Num mber o per y Leukemia Other cancers 0 10 20 30 40 50 Years since atomic bombing 5.2.2.Distinguishingradiation-relateddiseases Noknowndiseasesareuniquetoradiation-exposedpersons.IfanAbombsurvivorbecomessick,itcannotbededucedthatthediseasewas directlycausedbya-bombexposure.thus,itbecomesnecessaryto 11
comparediseaseratesamongpersonsexposedtosignificantradiationdoses withratesamongpersonsexposedtonegligiblelevelsofradiation.thisis anexampleofanepidemiologicalcohortstudy.suchinvestigationhasshed lightontherelationshipbetweenradiationexposureanddisease. 5.2.3.Deathsduetocancer Inadditiontoleukemia,evidencehasbeenobtainedthatthereisan increaseindeathsfrom cancersofthestomach,lung,colon,breast,andso on.however,noincreasehasyetbeenobservedforuterine,pancreatic,and prostatecancers. Cancerrateshavebeenfoundtoincreaseinproportiontoradiation dose(seefigure8onpage14).thetablebelowshowsaveragerelative risk * forleukemiamortalityandothercancerincidenceormortalitydueto exposuretoaweighteddoseof1gy. Table.Relativeriskofleukemiaandcancerduetoradiationexposureto aweighteddoseof1gy Relativerisk Leukemia Othercancers About5 About1.5 Note:Sex-averagedrelativeriskforsurvivorsexposedatage30 Foralpersonsdirectlyexposedwithin2.5km (meanweighteddoseof around0.2gy)amongthererf slifespanstudysubjects(seepage19), theoveralrelativeriskforleukemiaisabout2.0,whilethatforother cancersisabout1.1(seethefigureonpage20). 12
5.2.4.Cancerdevelopment Althoughcancerwasvirtualyanincurablediseaseinthepast,itcan now,inmanycases,becuredifitisdetectedearly.therefore,itis necessarynotonlytostudycancerdeaths,butalsotostudythegeneral situationsuroundingcancerdevelopment,inordertounderstandtheefects ofa-bombradiationonhumanhealth.althoughthisisnotaneasytask, cancerregistrysystemshavebeeninplaceinthecitiesofhiroshimaand Nagasakisincethe1950s,thankstotheefortsofthelocalmedical associations.thesystemsarecontinuedtodayasthehiroshimaprefectural andcitycancerregistriesandthenagasakiprefecturalcancerregistry. Figure7showscancerincidenceasobtainedfrom theseregistries.the numbersofcancerdeathsarealsoshownforcomparison.nomajor Figure7.Comparisonbetweenthenumberofcancercasesandcancerdeaths. Thenumberofdeathsforskincancer,breastcancer,andthyroid cancerismuchsmalerthantheirincidence(1958 2002). 13
diferenceexistsbetweenincidenceanddeathsforcancersoftherespiratory organsandthehematopoieticsystem.thesameisnottrue,however,for othercancers.forexample,asimpleoperationattheearlystagescancure skincancer,whichisoftenvisible.earlydetectionofbreastcancerisalso possiblebydirectpalpationoftheafectedsite.acharacteristicofthyroid cancer,whichcannotbedetectedbytouch,isitslowerlevelofmalignancy comparedwithothercancers.amongsuchcancers,itisobviousthatthe numberofdeathsissignificantlylesthanthenumberofcases. Figure8showstherelationshipbetweenradiationdoseandthe developmentofalcancersexcludingleukemia.therelationshipisgeneraly linearinnature.thefigureshowsthatcancerincidenceincreasesbyafactor of1.5withanexposuretoradiationofabout1gy. Figure8.Relationshipbetweenradiationdoseandtherelativeriskof incidenceofalcancers,excludingleukemia 2.5 2 Actual data points Linear Relative risk 1.5 1 0.5 0 0 1 2 3 Weighted absorbed colon dose (Gy) 14
5.2.5.Variationdependingonageatthetimeofexposure Increasedcancerincidenceisrelatednotonlytoradiationdose,butalso toageatthetimeofradiationexposure.itisknownthatlifetimecancerrisk ishighestamongthoseexposedtoa-bombradiationwhenyoung.since thosewhowereexposedtoradiationwhen10yearsoldoryoungerarenow intheirsixtiesandseventiesandreachingtheircancer-proneyears,early detectionandtreatmentareimportant. 5.2.6.Noncancerdiseases Efectsofradiationexposurearenotconfinedtocancer(malignant tumor).presently,diseasesthatshowaclearassociationwithradiationare benignthyroidtumors,benignparathyroidtumors,uterinemyoma,and gastricpolyp.inaddition,ithasbeensuggestedthatradiationexposuremay haveanefectondeathscausedbyheartandliverdiseases.studiestoverify thishypothesisareongoing. 5.2.7.Efectsofprenatal(inutero)exposure Braindevelopmentwasafectedforsomepeoplewhowereexposed whilestilinthewomb(a-bombmicrocephaly, * intelectualimpairment, anddecreasediq).thisefectwasnotobservedinthosewhowereexposed toa-bombradiationwhentheywerechildrenoradults.personsexposed duringweeks8 15ofgestationhaveshownthehighestrisk(Figure9).This isprobablybecausefetalbraincelsareparticularlysusceptibletoradiation damageduringthisperiod,duetotheiractiveceldivisionandproliferation. Theefectofaslightdeclineinthepost-birthgrowthofprenatalyexposed childrenhasalsobeenobserved. Mortalityandcancerincidenceforthispopulationhavealsobeen studied.todate,thecancerincidenceofthoseexposedprenatalytendsto increasewithradiationdoseatacomparableratewiththeincidenceamong thoseexposedwhentheywerechildren. 15
Figure9.Frequencyofintelectualimpairmentamongprenatalyexposed survivorsinrelationtoradiationdose 5.2.8.EfectsonthechildrenofA-bombsurvivors Intheaftermathoftheatomicbombings,oneofourconcernshasbeen todeterminewhetherabnormalitiesincreasedamongthechildrenborntoabombsurvivors.atthetimeresearchwasinitiatedin1948,japanstil employedarationingsystem,whichdatedtothemiddleofthewar,for certainfood.outofconsiderationfortheirhealthinparticular,therewasa specialrationforpregnantwomen.throughuseofanapplicationforthis specialration,morethan90% ofwomenpregnantatleastfivemonthswere confirmed,andthereafterafolow-upstudywasconductedtoobtain informationonmiscariageandmalformationatthetimeofbirth(physicians examinedapproximately77,000newbornindividualsfrom 1948 1954). Alsoconductedwereastudyonchromosomes(ofapproximately16,000 subjectsfrom 1967 1985)andastudyonhemoprotein(ofapproximately 24,000subjectsfrom 1975 1985).A mortalitystudy(ofapproximately 16
77,000subjectsfordeathsduetoleukemia,cancer,andothercausesfrom 1946tothepresent)andacancerincidencestudy(ofthesamesubjectsfrom 1958tothepresent)havealsobeenconducted.Todate,noincreaseofsuch abnormalitiesamongthea-bombsurvivors childrenduetoparentalabombradiationexposurehasbeenobserved.recently,genomicstudieshave alsobeeninitiated.healthexaminationswereconductedtodetectdiseases includingcancer,heartdisease,hypertension,anddiabetesconsideredtobe undetectableatbirth(forapproximately12,000subjectsfrom 2002to2006), aswelasprecursorstatesofthediseases.thehealthexaminationstudyis ongoing. 6.Publicationofresearchfindings TheresearchfindingsofRERFhavebeenpublishedasscientificpapers innationalandinternationaljournals,andalsoaspartoftechnicalbooks. RERF stechnicalreports,whichhadbeenprintedandpublishedin-house since1959,werediscontinuedafterpublicationofthe1992issuesand succeededbythererfreportseriessince1993.thererfreports consistofpublicationscariedinscientificjournals,withajapanese summary.whennecessary,paperswithtoomuchdataforpublicationina journalarepublishedasspecialreports. On thererfwebsite(htp:/www.rerf.jp/),variousstudiesare explainedindetail from theirbackgroundtotheirresults.datausedforthe riskestimationofa-bomb-relatedcancerscanalsobefreelydownloaded from thehomepage. Whendataaremadeavailable,studyparticipantshavebeengroupedby severalfactors,suchasdose,sex,andthelike,sothatindividualscannotbe identified.alpersonalinformationiscloselymanagedbyrerftoassure protectionofthehumanrightsofa-bombsurvivors. 7.Internationalcolaborationsandourhopes RERFactivelyparticipatesininternationalcolaborations.Thismakes theexperienceandknowledgegainedthroughourstudiesofa-bomb 17
survivorswidelyavailableforthebenefitoftheworld.suchactivity involvescooperationwithinternationalorganizationsincludingtheunited NationsScientificCommiteeon theefectsofatomicradiation (UNSCEAR),theWorldHealthOrganization(WHO),andtheInternational AtomicEnergy Agency(IAEA).TheInternationalCommission on RadiologicalProtection(ICRP)hasissuedrecommendationsonradiation exposuredoselimitsbasedonrerfstudyresults,andtherecommendations havebeenpromulgatedthroughouttheworld.rerfhasthuscontributedto theestablishmentofglobalradiationprotectionstandards. Additionaly,severalprojectswereinitiatedasaconsequenceofthe accidentatthechernobylnuclearpowerplantonapril26,1986.onewas thehiroshimainternationalcouncilforhealthcareoftheradiationexposed(hicare),organizedonthebasisofcolaborationamong HiroshimaPrefectureandCity,localmedicalassociations,universities, hospitals,andresearchinstitutes.thenagasakiassociationofhibakushas MedicalCare(NASHIM),operatedbyNagasakiCityandPrefecture,local medicalassociations,andotherrelatedorganizations,wasanothersuch project.thepurposeoftheseprojectsistotrainphysiciansandresearchers from countrieswherepeoplehavebeenexposedtoradiation.rerfannualy acceptsmorethan100short-term traineesandseverallong-term trainees throughtheseprojects. In1996,theA-bombDomeinHiroshimawasdesignatedaworld heritagesite.thisdesignationwasveryimportanttothecityonwhichtheabombwasdropped.atthesametime,wemustremainmindfulofthose peoplealovertheworldwhohavebeenexposedtoradiationandconsider HiroshimaandNagasakitobetheplaceswheretheycanacquirethemost reliableknowledgeaboutradiationexposure.rerf smision,tocontribute tothewelfareandmedicalcareofa-bombsurvivors,alsoincludes contributiontomedicaltreatmentandhealthstudiesforpeoplethroughout theworldexposedtoradiation.wehopethatourknowledgeandexperience canmakethisresearchinstitutionworthyoftherecognitionhiroshimaand Nagasakiclaim aroundtheworld.tothisend,rerfconsidersclose colaborationandcooperationwiththelocalcommunitiesofhiroshimaand Nagasakitobeofutmostimportance. 18
Appendix1 CharacterizationoftheRERFstudypopulations LifeSpanStudy(LSS)population Consisted ofabout120,000 personsatthelaunch ofthestudy. Epidemiologicalstudiesofthecausesofdeathandofthedevelopmentof cancerarecariedoutonthispopulation. AdultHealthStudy(AHS)population Consistedofabout20,000personsatthelaunchofthestudy.Through biennialhealthexaminationsandmailquestionnaires,diseasesare detectedattheirearlystages,andotherspecifickindsofhealthproblems arestudied. Inuteropopulation Consistsofabout3,600persons.Studiesofmicrocephalyandintelectual impairmentwerecariedoutinthepast.atpresent,analysesofthecauses ofdeath,includingthoseduetocancer,arebeingcariedout. F 1population Consistsofabout77,000persons.Studiesofdeformitiesandhereditary disorderswerecariedoutinthepast.atpresent,epidemiologicalstudies ofthecausesofdeath,includingthoseduetocancer,arebeing conducted.insubsetsofthispopulation,abnormalitiesinbloodprotein (about24,000persons)andchromosomes(about16,000persons)were studied.clinicalexaminationsonasubsetofabout12,000personsare alsounderway.preparationsforthednastudyofabout1,000families areunderway,withapilotstudyalreadybegun. 19
Appendix2 InformationrelatedtoA-bombsandradiation NumberofdeathscausedbyA-bombs Theprecisenumberisunknown.Thenumbersofdeathsbytheendof 1945areestimatedtobe140,000(±10,000)and70,000(±10,000)in HiroshimaandNagasaki,respectively. TotalnumberofA-bombsurvivors In1950,whenthefirstNationalCensusafterWorldWarIwascariedout, asmanyas284,000personsindicatedthattheyhadbeenexposedtothe atomicbombingsofhiroshimaandnagasaki.thisfiguredoesnotinclude earlyentrants (thosewhohadenteredthecitiesafterthebombings).the LSSandAHSpopulationsmentionedinAppendix1wereestablishedby selectinga-bombsurvivorsidentifiedfrom thiscensus. PercentageofA-bombsurvivorsRERFhasfolowedofthetotal numberofa-bombsurvivors Thenumberofsurvivorsthathavebeen folowed in thererf epidemiologicalstudiesisestimatedtobeslightlylessthanhalfofthose exposedwithin2.5km from thehypocenter,andaboutaquarterofthose exposedbeyond2.5km,althoughtheexactnumberofexposedis unknown. NumberofleukemiadeathsandcancercasesamongtheLifeSpan Studysubjects ThenumbersofleukemiadeathsandcancercasesamongA-bomb survivorsexposedtoatleast0.005gyinthelifespanstudycohortare showninthefigurebelow.theblackareas(93outof204leukemia deathsand850outof7,851cancercases)indicateexcesleukemiadeaths andcancercasesatributabletoradiationexposure. Leukemia (Deaths) (1950 2000) 93/204 (46%) Cancers (Incidence) ((1958 1998) ) 0 2000 4000 6000 850/7,851 (11%) 8000 (cases) 20
Appendix3 Glosary AtomicBombSurvivorsSupportLaw(page2) Enactedin1994,thislaw integratedtheprevioustwolaws:thelaw ConcerningSpecialMeasuresfortheAtomicBombExposedandtheAbombSurvivorsMedicalTreatmentLaw.ItstipulatesthattheJapanese governmentshould assume the responsibility of implementing comprehensivereliefmeasuresforthehealth,medicalcare,andwelfare oftheatomicbombsurvivors. A-bombSurvivorsMedicalTreatmentLaw(page3) Establishedin1957,thislawdecreedthatA-bombsurvivorswereentitled toa-bombsurvivors healthhandbooks,biannualhealthexaminationsfor beterhealthmanagement,detailedhealthexaminationsintheeventthat anyabnormalitywasfound,andmedicalcompensationiftheywere certifiedaseligiblebytheministerofhealthandwelfare.these measureswereincorporatedintotheatomicbombsurvivorssupport Lawin1995. Nuclearfusion(page4) Thefusingoftwonucleiathightemperatures,whichistheoppositeof nuclearfision.nuclearfusionalsoemitsenormousamountsofheat. Nuclearfision(page4) Uranium andplutonium havelargeandunstableatomicnuclei,which spontaneouslysplit(fission)andemitheat.whenaneutronemitedasa consequenceofnuclearfisionisabsorbedbyanothernucleus,thiscauses anotherfissionreaction,whichcausesfurtherfission,andsoon, producingachainreaction(principlebehindatomicbombs). Shielding(page4) Radiationlosesitsenergyinvaryingdegreeswhenitpenetrates substances.leadisusedasashieldagainstgammaandx rays.the shieldingefectofconcretebuildingsisfargreaterthanthatofwooden houses. Residualradiation(page4) Therearetwosourcesofresidualradiation.Oneisfalout,andtheother isneutronactivation(inducedradiation).faloutoccuredasblackrain, 21
whichcontainedtheradioactivefissionproductsofuranium (Hiroshima) orplutonium (Nagasaki),aswelasnuclearsubstancesthathadnot undergonenuclearfision.thedoseswerehighestinareaswheretherain fel thenorthwesternpartofhiroshimaandtheeasternpartofnagasaki. Neutronactivationoccuredwhenneutronsreleasedfrom thebombhit materialsinthesoilorbuildings,resultinginthegenerationofradioactive atoms.inthiscase,thedoseswerehighestatthehypocenters. Electromagneticwave(page6) Electromagneticwaveshavecharacteristicsofbothwavesthattravelat thespeedoflightandparticles.thisgeneralterm isusedforelectric, infrared,visible,ultraviolet,x,andgammarays,amongothers. Cosmicrays(page6) Varioustypesofradiationoriginateinthecosmos.Theradiationis thoughttobeproducedwhenstarsform orburnout.althoughmost cosmicradiationisabsorbedintheatmosphere,somedoesreachthe ground. Cobalt-60(page7) Cobaltisastableelementthatusualyhas27protonsand32neutronsin thenucleus,withanatomicmassnumberof59.(cobaltisusedfor makingbluepigment.)however,cobaltwith33neutrons(cobalt-60), whichisproducedbythenuclearfissionofplutonium,isunstableand emitsradiation. Nucleardecay(page7) Nucleardecayistheprocesbywhichanatomicnucleusbreaksdownto form adiferentelement(disintegration).extraenergyisemitedas radiationduringtheproces. Gray(Gy)(page7) Onegray(Gy)representsthedose,regardlessofradiationtype,when 1joule(J)ofenergyisabsorbedby1kilogram ofagivensubstance. Sievert(Sv)(page7) Sievert(Sv)hastwodiferentuses.Oneis equivalentdose, whichis obtainedbymultiplyingthetissue-absorbeddose(ingy)byafactor weightedinaccordancewithtypeofradiation.theotheris efective dose, whichisobtainedbymultiplyingthetisue-equivalentdose(insv) byafactorthattakesintoaccountdiferencesinhealthefectdepending 22
onafectedtisue.bothunitsareusedforradioprotectivepurposes.rerf usesequivalentdoseweightedinaccordancewithtypeofradiation,but sincetissue-specificfactorsarenotincorporatedintothiscalculation,gy isusedinsteadofsvtoavoidconfusionwithefectivedose. DS02(DosimetrySystem 2002)(page8) Thisisthelatestsystem usedtoestimateradiationdosesfrom theatomic bombs.becauseofthequestionsconcerningevaluationofneutronsinthe DS86,whichwasdevelopedin1986,severalyearswerespenton reassessment.usingup-to-dateknowledgeofnuclearphysicsand computertechnology,amoreaccurateandimprovedsystem wasfinalized in2002,caledds02.italowscalculationnotonlyofindividualdoses, butalsoofthedosestowhichdiferentorganswereexposed(organ doses),onthebasisofthedataobtainedfrom individuala-bomb survivors. Inducedradiation(page10) Pleaserefertothedescriptionofresidualradiation(page21). Radiationcataract(page11) Radiationcataractoccurswhentheposteriorofthelensofaneyeclouds atthecenter,eitherinaroundoradonutshape,asaresultofdamageto someofthecelsmakinguptheeyelens. Relativerisk(page12) Theterm relativerisk isusedheretorefertohowmuchhighertherisk ofcancerisinthoseexposedtoa-bombradiationcomparedwiththe cancerriskinnon-exposedpeople.( Risk indicatesthepossibilityof danger.) A-bombmicrocephaly(page15) Microcephalyiscausedwhentheactivelyproliferatingcelsofthefetal brainbecomedamagedbyradiationandareunabletoproduceasuficient numberofbraincels. 95% confidenceinterval(page16) Thisconfidenceintervalisameasureofthereliabilityofanestimated valueandindicatesthatthevaluefalsintheintervalrangewitha95 percentlikelihood.thewidertheconfidenceinterval,thelesreliablethe givenvalueis. 23
Appendix4 IntroductiontotheRERFdepartments DepartmentofEpidemiology:Thisdepartmentstudiesover200,000Abombsurvivorsandtheirchildren,primarilyforincidenceofcancerand causeofdeath.inepidemiologicalstudiesitisimportanttofolowafixed populationforalongtime.intermsofthescale,meanradiationdose,and duration,thererfstudypopulationisthelargestintheworld. DepartmentofStatistics:Thisdepartmentisresponsibleforanalysesof thestatisticalproblemsthatarisefrom thestudyofa-bombradiationefects andsupportofotherresearchdepartments,aswelasoveraldosimetry work,includingradiationdosecalculationfora-bombsurvivors. DepartmentofClinicalStudies:Thisdepartmentconductsbiennialhealth examinationsofthehiroshimaandnagasakia-bombsurvivors,aninitial populationofsome20,000.theseexamsareconductedforthedualpurpose ofdetermininghealthstatus includingpsychologicalhealth anddetecting diseasesatanearlystage.theresultsofthesehealthexaminationsarethen sharedwiththeparticipants,whoarereferedtospecializedhospitalswhen necesary. DepartmentofGenetics:Thisdepartmentstudiesthehealthstatusand DNAofchildrenofA-bombsurvivors.Thedepartmentalsomeasuresthe bloodcelsofsurvivorsforchromosomeaberationsandanalyzesteethfor tracesubstancesproducedbyradiationtoestimateradiationdoses. DepartmentofRadiobiology/MolecularEpidemiology:Thisdepartment studiestheefectsofradiationontheimmunesystem,seekstodetermineif thereareanyabnormalitiesinthegenesofbloodcels,andalsoconducts geneanalysisofcancercels. DepartmentofInformationTechnology:ThisdepartmentmanagesinformationinvestigatedandanalyzedineachofthedepartmentsatRERFand disseminatesinformationthroughouttheworld.itisalsoinchargeofthe managementofrerfscientificpapers,publicationsandvariousmaterials, aswelaslibraryoperations. Secretariat:TheSecretariatconductsgeneraladministrativeworktosupport theresearchdepartments,includingactivitiesregardingcommunicationof researchfindingsaswelaseditingofrerf spublicationsandwebsite. 24
Memo 25
ToursoftheRadiationEfectsResearchFoundation Ourfacilitiesareopenforindividualorgrouptoursthroughoutthe year.pleasecontactusinadvanceforaguidedtour.reservationsforguided toursalsocanbemadeonourhomepage. Toursavailable:9:00 16:00,MondaythroughFriday (excludingholidays) Firstedition:August5,1995 Seventhrevision:May1,2015 Publishedbythe RadiationEfectsResearchFoundation 5-2HijiyamaPark,Minami-ku,Hiroshima,732-0815 Phone:082-261-3131(switchboard) 1-8-6Nakagawa,Nagasaki,850-0013 Phone:095-823-1121(switchboard) Homepage:htp:/www.rerf.jp/ 26