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Radiopharmaceu-calsininfec-onimaging
AlbertoSignore,MD,PhDProfessorofNuclearMedicine,FacultyofMedicineand
Psychology,“Sapienza”UniversityofRome,Italy
HonoraryFullProfessoratDept.ofNuclearMedicineandMolecularImaging,UniversityMedicalCenterGroningen,The
Netherlands
ChairoftheInflammaHon/InfecHonCommiJeeoftheEuropeanAssociaHonofNuclearMedicine(EANM)
AMRin205010,000,000
1deathevery3seconds
ReviewonAn*microbialResistance2014
Tetanus60,000
Cholera110,000
Measles130,000
AMR700,000
Roadaccidents1,200,000
Diarrhoealdisease1,400,000
Diabetes1,500,000
Cancer8,200,000
MonselAetal.Anesthesiology2014;121:1099-121
Inflamma-onvsInfec-on
AcuteorchromicsepHcinflammaHon(infecHon)(mainlygranulocyte-mediated)
AcuteorchronicsterileinflammaHon(mainlymononuclearcell-mediated)
InflammaHonisaprotec-veresponseinvolvinghostcells,bloodvessels,andproteinsandothermediatorsthatisintendedtoeliminatetheiniHalcauseofcellinjury,aswellasthenecroHccellsandHssuesresulHngfromtheoriginalinsult,andtoiniHatetheprocessofrepair.
AlthoughinflammaHonhelpsclearinfecHonsandothernoxioussHmuliandiniHatesrepair,theinflammatoryreacHonandthesubsequentrepairprocesscanthemselvescauseconsiderableharm.
Acuteinflamma-onisrapidinonsetandofshortduraHon,lasHngfromafewminutestoaslongasafewdays,andischaracterizedbyfluidandplasmaproteinexuda-onandapredominantlyneutrophilicleukocyteaccumulaHon.
Chronicinflamma-onmaybemoreinsidious,isoflongerduraHon(daystoyears),andistypifiedbyinfluxoflymphocytesandmacrophageswithassociatedvascularprolifera-onandfibrosis(scarring).
AcuteinflammaHoncanbetriggeredbyInfec*ons(bacterial,viral,fungal,parasiHc),Traumaandvariousphysicalandchemical,Tissuenecrosisincludingischemiaandphysicalandchemicalinjury,Foreignbodies,andImmunereac*ons(alsocalledhypersensiHvityreacHons).
Pathophysiologyofinflamma-on
SignoreA.EJNMMIResearch2013;3:8SignoreA.EJNMMIResearch2013;3:8
Radiopharmaceu-calsforinfec-onimaging
SignoreA.etal.AnnNuclMed2011
RadiolabelledCiprofloxacin
AuleLaS.etal.ClinTransImaging2016;4:229-252
Othertestedan-bio-cs
AuleLaS.etal.ClinTransImaging2016;4:229-252
Imaginginfec-onsbytarge-ngbacteria
Radiolabelledprobe
Invitrospecificity
Animalmodel
Clinicalspecificity
Whatkindofanimal?
Howmanybacteria?
Whatkindofmodel?
Appropriatecontrol?
Comparisonofdifferentan--microbialagentsfortarge-ngbacterialinfec-ons
AuleLaS.etal.QJNMMI2017;[Epubaheadofprint]
DistribuHonprofileofradiopharmaceuHcalsatdifferentHmepointsintocagefluids(dispersedbacteria)
Datarepresent%ID/mlofHssuefluid,expressedasmeans±SEMofthreetofivemicepertesHnggroup.Significantdifferencesbetweeninfectedandcontrolfluidsareindicatedasfollow:*P<0.05,**P<0.005,***P<0.0005.
*
*
30 min 4 h 24 h0.0
0.5
1.01.5
2.0
2.5
3.0
3.5
4.0
%ID
/ml
99mTc-UBI
30 min 4 h 24 h0.0
0.1
0.2
0.3
0.4%
ID/m
l
99mTcN-CiproCS2
30 min 4 h 24 h0
1
2
3
4
5
%ID
/ml
99mTc-Ciprofloxacin
30 min 4 h 24 h0.0
0.2
0.4
0.6
1.0
1.5
2.0
2.5
%ID
/ml
111In-biotin111In-DTPA-bio-n
à Sterilefluid
30 min 4 h 24 h0.0
0.5
1.01.5
2.0
2.5
3.0
3.5
4.0
%ID
/ml
99mTc-UBI
30 min 4 h 24 h0.0
0.1
0.2
0.3
0.4
%ID
/ml
99mTcN-CiproCS2
30 min 4 h 24 h0
1
2
3
4
5
%ID
/ml
99mTc-Ciprofloxacin
30 min 4 h 24 h0.0
0.2
0.4
0.6
1.0
1.5
2.0
2.5
%ID
/ml
111In-biotin
**
99mTc-UBI
*
**
*
99mTc-ciprofloxacin
30 min 4 h 24 h0.0
0.5
1.01.5
2.0
2.5
3.0
3.5
4.0
%ID
/ml
99mTc-UBI
30 min 4 h 24 h0.0
0.1
0.2
0.3
0.4
%ID
/ml
99mTcN-CiproCS2
30 min 4 h 24 h0
1
2
3
4
5
%ID
/ml
99mTc-Ciprofloxacin
30 min 4 h 24 h0.0
0.2
0.4
0.6
1.0
1.5
2.0
2.5
%ID
/ml
111In-biotinà E.colifluidàS.aureusfluid
Datarepresent%ID/gofHssue,expressedasmeans±SEMofthreetofivemicepertesHnggroup.Significantdifferencesbetweeninfectedandcontrolcagesareindicatedasfollow:*P<0.05,**P<0.005,***P<0.0005.
Comparisonofdifferentan--microbialagentsfortarge-ngbacterialinfec-ons
DistribuHonprofileofradiopharmaceuHcalsatdifferentHmepointsintoexplantedcages(biofilm)
à Sterilefluid à E.colifluidàS.aureusfluid
99mTc-UBI 99mTc-ciprofloxacin 111In-DTPA-bio-n
AuleLaS.etal.QJNMMI2017;[Epubaheadofprint]
Conclusionsonbacteriaimaging• Imagingbacteriaisadifficultandchallengingtask
• Animalmodelsshouldbecarefullyselectedandstandardizedawellasbacteriastrains
• Experimentaldesignshouldincludeinvitroandinvivostudieswithappropriatecontrols
• CauHonshouldbetakenwhenusing[18F]FDGforimaginginfecHons
• SinceWBCscinHgraphyshowedexcellentdiagnosHcaccuracyforimaginginfecHonsinhumans(>98%),bacterialimaginghasapotenHalassecondlineimagingtoolforidenHfyingthegermresponsibleforinfecHonandfollow-uptheefficacyoftailoredtherapies
Pros Cos Target Dosimetry Costperpa-ent
67Ga-citrate
150€
111In-WBC
300€
99mTc-WBC
300€
ScinHmun®
350€
Leukoscan®
350€
18F-FDG
1000€
Commerciallyavailableradiopharmaceu-calsforimaginginfec-on
Gallium-67
• CyclotronproducedbyprotonbombardmentofZn-68ina(p,n)reacHon• Pricedependsonhowmuchyouuse• LongT1/2poordosimetryxxhr• AcHvitylimited150MBqintheUKwithanEDof18mSv• Imagingon90,190,300keV• But5%yieldon394keVmeansneedmed/highcollimator
Gallium-67citrate
• ActsasanalogueofFe,carriedonTransferrin/lactoferrin,willfollowIron• Theseareacutephaseproteins• CytochromeP450needsFe• Sodomanybacteria(havereceptorsforhumanTF/LF)• SlowlocalisaHonatsiteofinfecHon/inflammaHonandsometumours• Inbloodmainlyproteinboundaserabout6hoursbeforethismaycirculateasfreeion• First24hoursexcreHonofnon-boundfracHonviakidneys,thenexcretedasproteinboundfracHonintoileum/caecum
Characteris-csof67Ga-citrate
• ColonicandbonemarrowacHvityvariable• BreastacHvitycanoccurinpreg/lact/leutphase/HRT• WillbeverysensiHveformostinfecHonincludingpneumocysHsandTB• Problemwithimagingascountscanbelowinperiphery.SPECTdifficultbutpossible• Imagingoutto7dayspossiblebutcountsreduced• SomeuptakeinmetabolicallyacHvebonesforexamplerecentfractures• MaybebestforvertebralinfecHons
67Ga-citrateindica-ons
• MostcommonindicaHonsfor67Ga-citratesupersededbynewertests
• However,inspecialcases67Gamayhavearole• Intheneutropenicwhen[18F]FDGnotpossible• InvertebralosteomyeliHswhenwhitecelllabellingtechniquesareatadisadvantage
• InsomechronicinfecHonssuchastuberculosis• Inassessingsarcoid.
Slide16
Advantagesof67Ga-citrate• Doesnotneedcelllabelling• UsefulifpaHentisneutropenic• UsefulifinfecHondoesnotlocaliselabelledleucocytessuchaschronicTBandpneumocys2scariniiinfecHons,spondylodisciHs
• Usefulifbloodinfected(HIV,HCV,HBV)• AvailableasstockitemandrelaHvelycheap• Canbeorderedinadvanceifsufficientuseaslonghalflifeaidsstorageoverafewdays
Slide17
Disadvantagesof67Ga-citrate• PoorlyspecificforinfecHon,canimageinflammaHonandtumors• NotunivocalinterpretaHoncriteriaforimages• Longhalflifeandpoordosimetry(nouseinchildren)• CannotbeusedinpaHentstakingironbinders
67Ga-citratedosimetry
Organ ReferencedosemGy/MBq
Largebowel 0.2432
RedMarrow 0.1568
Spleen 0.1432
Liver 0.1243
Bone 0.1189
Smallbowel 0.0973
Ovaries/testes 0.0703
Wholebody 0.0703
SourceJNM1973;14:755-6ED0.012mSv/MBqformaximum150MBq=18mSv
Pros Cos Target Dosimetry Costperpa-ent
67Ga-citrateNolabelling,cheap,imagebacteriaandvertebralOM
Longhalf-life,poorimages,poorlyspecific,highradiaHon
Transferrin,bacteria,
acHvatedcells(Kreb’scycle)
18mSv(largebowel) 150€
111In-WBC
99mTc-WBC
ScinHmun®
Leukoscan®
18F-FDG
Commerciallyavailableradiopharmaceu-calsforimaginginfec-on
LabelledWBCs• RadiopharmaceuHcalsusedforWBClabelling• In-111oxine• In-111tropolone• Tc-99mexemetazime(HMPAOhydroxymethylpropyleneamineoxime)
• AllcomplexesarelipophilicaminesthatenterleucocytebydiffusionandaretrappedinsidecellaserreducHon(glutathione)• Leucocytesneedtoremainalive,notacHvatedandsterile• LabellingoriginallydescribedinplasmabutcanalsobedoneinsalineorPBS(compulsoryforoxine)
Whichradiopharmaceu-calforWBClabelling
• In-111WBCs• Max90MBq• Uptakeinliver,spleenandBM• NobileexcreHon• Poorcountsinperiphery• Mediumenergycollimator• SPECT-CTnotideal
• Tc-99mHMPAOWBCs• Max555MBq• Highliverandspleenuptake• BileexcreHonandbowelacHvityaser3-4hours• Lowenergycollimator• GoodforSPECT/CTbutlowcountrateat20h
Slide21
Slide22
• AccumulaHonininfecHonsisadynamicprocess• DualHme-pointimaging(3-4and20-24hoursaserinjecHon)isnecessary;whenpossibleacquirealsoearlyphase(30min)images
RadiolabelledWBCforinfec-onimaging
HowtoacquireWBCandan--Gimages?
Signare A, Quintero AM. Diagnostic imaging of infections &inflammatory diseases: a multidisciplinary approach J. Wiley Pbl. 2013
Acquisi-on-me-tablecorrectedforisotopedecay
Criteriaforposi-vity:-AnyuptakewithincreaseofacHvitywithHme-AnyuptakewithincreaseofsizewithHme
Sequen-alWBCimagingfordiagnosisofinfec-on
Definespecifickine-cpaXernsofradiopharmaceu-cals
99mTc-HMPAO-leukocyte scintigraphy in a patient with bilateral knee prostheses and suspected left knee prosthesis infection. Quantitative analysis: SRearly = 64.7; RRearly = 61.9; SRlate = 28.1; RRlate = 13.7; T/Bearly = 1.05 T/Blate = 2.05
Qualita-veorsemi-quan-ta-veanalysis?
Pelosi E. et al. J Nuc Med 2004;45:438-444
Infec-on
Noninfec-on
111In-WBC 99mTc-nanocolloid
CombinedbonemarrowandWBCimagingfordiagnosisinfecHon
Combinedbone-marrowscantoiden-fyac-vedisplacedbonemarrow
IsitanybeXertouseSPECT/CT?
L.Filippi et al. J Nuc Med 2006
111In-oxine-WBCdosimetry
Organ ReferencedosemGy/MBq
Spleen 0.703
Liver 0.103
RedMarrow 0.0703
Bone 0.00197
Testes 0.0005
Ovary 0.0102
Wholebody 0.0168
SourceMedi-physicsED0.45mSv/MBqformaximum90MBq=9mSv
Organ ReferencedosemGy/MBq
Spleen 0.0755
Kidneys 0.0184
Bladderwall 0.0177
GallBladder 0.0148
Lungs 0.0141
Colon 0.0105
Pancreas 0.0098
Wholebody 0.0038
SourceJNM2008;49:1380-1385ED0.0137mSv/MBqformaximum400MBq=5.56mSv
99mTc-HMPAO-WBCdosimetry
Pros Cos Target Dosimetry Costperpa-ent
67Ga-citrateNolabelling,cheap,imagebacteriaandvertebralOM
Longhalf-life,poorimages,poorlyspecific,highradiaHon
Transferrin,bacteria,
acHvatedcells(Kreb’scycle)
18mSv(largebowel) 150€
111In-WBCGoodfor
inflammatoryboweldiseases
SterilebloodmanipulaHon,poorimaging
Mainlyneutrophils
9mSv(spleen) 300€
99mTc-WBCGoodforboneandjointinfecHons,goodSPECTimages
SterilebloodmanipulaHon,
bowelexcreHon,notforspondylo
Mainlyeosinophils
5.6mSv(spleen) 300€
ScinHmun®
Leukoscan®
18F-FDG
Commerciallyavailableradiopharmaceu-calsforimaginginfec-on
InvitroWBClabelingwithdisposablesterilecloseddevice
InvitroWBClabelingwithLeukokit®
1 2
3
InvitroWBClabelingwithLeukokit®
Pros Cos Target Dosimetry Costperpa-ent
67Ga-citrateNolabelling,cheap,imagebacteriaandvertebralOM
Longhalf-life,poorimages,poorlyspecific,highradiaHon
Transferrin,bacteria,
acHvatedcells(Kreb’scycle)
18mSv(largebowel) 150€
111In-WBCGoodfor
inflammatoryboweldiseases
SterilebloodmanipulaHon,poorimaging
Mainlyneutrophils
9mSv(spleen) 300€
99mTc-WBCGoodforboneandjointinfecHons,goodSPECTimages
SterilebloodmanipulaHon,
bowelexcreHon,notforspondylo
Mainlyeosinophils
5.6mSv(spleen) 130€
ScinHmun®
Leukoscan®
18F-FDG
Commerciallyavailableradiopharmaceu-calsforimaginginfec-on
An-bodies• AnHbodiesarecomplexproteinsmadeupoftwolongchainscalledtheheavychainsandtwoshorterchainsthelightchains,bothconnectedbysulphidebridges• SimplestformIgGwithamolecularweightof150kDa• TheCterminalsofthetwoheavychainshaveasinglecharacterisHcineachspecies(Fc=constantfactor)• TheNterminalsoftwolightandtwoheavychainsvarydependingontheanHgentheyrecognisethe(Fab=anHgen-bindingfactor)• IneachindividualtheFcwillbeconstant(foreachIgtype)buttherewillbeavarietyofFabporHons
Slide35
Monoclonalan-bodiesandHAMAs
• IfamonoclonalanHbodyisraisedagainstahumancelllineinamousethatanHbodycanbeinjectedbackintohuman• FabidenHfiestheanHgenandbinds• HowevermouseFccanitselfbecomeananHgensohumananHbodiescanberaisedagainstit• ThereforebyinjecHngamousederivedanHbodyitispossibletoinduceahumananHmouseanHbody(HAMA)• HAMAscanbindtooriginalanHbodiesandformimmuno-complexesthatmayprecipitateinkidneys
Slide36
Fromcompletean-bodiestoFab‘fragments
Papain
Fab Fc
CH2CH3
VL
CLVH
CH1
VL
CLVH
CH1
SchemaHcrepresentaHonofenzymaHccleavageofa
completeIgGintoFab’fragments(accordingGemsa,Kaldenand
Resch;Immunologie,P.17,ThiemeVerlag1997,4th
ediHon)
IgG 150 kD
Fab‘ 50 kD 99mTc / 111In
light chain
heavy chain
99mTc-an--granulocytemAb
• LicenceforosteomyeliHs• CouldbeusedinanysituaHonwherelabelledwhitecellsused• Howevernotgoodfor:
• Inflammatoryboweldisease(crossreacHvitywithCEA)• VertebralosteomyeliHs• NeutropenicpaHents
• Only2typesavailable,bothlabelledwithTc-99m
Slide38
99mTc-besilesomab(Scin-mun®)• DevelopedmainlyinGermany• BW250/183wholemouseIgGdevelopedbyLocheretal.atPaulShirerinsHtutenearZurich• WholemouseIgGdirectedagainstCD66(NCA-95)whichisaglycoproteinonsurfaceofhumangranulocyte• UsedprimarilyinboneandjointinfecHons• Rapiduptakeintobonemarrow,somerenalandbladderacHvity,laterbowelmaybeseen• RapiduptakeininfecHons.LateimagesnecessarytoshowincreasedaccumulaHonatinfecHonsites• TheoreHcalissuewithHAMAespeciallyifpaHenthasbeenexposedtomouseproteinsbefore
Slide39
• DevelopedbyGoldenburginUSA• Fab’fragmentofamouseanHbodytargetedtoNCA90• NorealriskofHAMA.Canbegivenmorethanonce• HighbackgroundandhighlevelsofacHvityintheblood,urinarysystemandgut• LicencedbyEMEAforperipheralinfecHonsonly• Becauseofhighbloodpooldifficulttoimagechest,abdomenandpelvis• SPECTmayhelp• SomedoubtthereisspecifictargeHng
Slide40
99mTc-sulesomab(Leukoscan®)
HAMAkit(MileniaQuickLine®)• Beforeopeningthevialsbringthetestunitandchasebuffertoroom
temperature(18-28°C).• Usethetestunitimmediatelyaseropening.• Donotstoreatroomtemperature.
Slide42
99mTc-IgG
99mTc-Fab`
99mTc-an--granulocytemAbSerumclearenceofIgGandFab`
99mTc-F(ab`)2
Note:TheFab’clearsmuchfasterthanIgGthusimagingbeyond4-6hourscanbeavoided 99mTc-F(ab`)2
Behr:CancerRes.1995
Gratz:EurJNuclMed.1998
99mTc-an--granulocytemAbSerumclearenceofIgGandFab`
Behr:CancerRes.1995Gratz:EurJNucMed.1998Gratz:QJNuclMed.2015
IgG Fab’
99mTc-an--granulocytemAbOsteomieliHstargeHng
Gratz:EurJNucMed.1998Gratz:QJNuclMed.2015
CorrelaHonbetweenT/BraHosof99mTc-sulesomaband99mTc-HSA(6h)andbetweenT/BraHosof111In-leukocytes(22h)and
99mTc-sulesomaband99mTc-HSA(6h).
Themechanismofac-onof99mTc-sulesomabremainsunclear,althoughitisnotrelatedto
intravascularbindingtocircula-nggranulocytes
SJ.Skehanetal.JNM44:11-18;2003
0
1
2
3
4
0 4 8 12 16 20
T/Bk
g(Sulesom
ab)
T/Bkg(111In-leukocytes)
o=HSA
Themechanismofac-onof99mTc-sulesomabremainsunclear,althoughithasbeensuggestedtoacquireimagesatboth4hand24hpostinjec-on
D.Rubelloetal.NucMedCommun25:39-47;2004
Itwouldperhapsbehelpful,here,todrawadisHncHonbetweentwodifferentdefiniHonsofspecificity:
- Radiopharmaceu-calspecificityistodowithwhetheranagentlocalizesinalesionthroughawell-definedphysiologicprocessforwhichitwasdesigned.
- Clinicalspecificityisameasureofthenumberoffalse-posiHveresults;
Thereappearstobeawidelyheldview,thatifaccumulaHon(i.e.,target-to-backgroundraHo)ofaradiopharmaceuHcalforinfecHonimagingconHnuestoincreaseover24h,theagentmustbespecificbythesecondofthesecriteria.
Labeledleukocytesarespecificonboth,butaradiolabeledprotein,suchaspolyclonalIgG,onlyonthefirst.ThatdoesnotmeantosaythatIgGwouldnotshowincreasinglocalizaHonoverHme.Itclearlydoes,andmoreover,99mTcdetachedfromtheproteinmayberetainedinHssue.Therefore,thefactthatanagent,including99mTc-sulesomab(LeukoScan;Immunomedics,Inc.),givesbeJerimagesat24hthrowsnolightonitsmechanismofaccumulaHon,whichcouldsHllbe“nonspecific.”
Themechanismofac-onof99mTc-sulesomabremainsunclear,despiteitsaccumula-oninaffected-ssuesmayincreasefrom4hto24hpostinjec-on
AM.Petersetal.JNM46:382-383;2005
InvivoWBClabellingwithan--granulocyteIgG(Besilesomab,Scin-mun®):lateimages
Bonescan Scin-munscan
Poolphase Earlyscan(4h)
Bonephase Latescan(20h)
27/11/17 Sousa R. et al. Nucl Med Commun 32:834;2011
Infected
Combined6himageswithcolloidscanfordisplacedbonemarrowidenHficaHon
InvivoWBClabellingwithan--granulocyteFab’an--NCA90(Leukoscan®)
Non-infected
Organ ReferencedosemGy/MBq
Spleen 0.0271
Bonemarrow 0.0242
Kidney 0.0210
Bone 0.0177
Lungs 0.0125
Liver 0.0100
Adrenals 0.00759
Wholebody 0.00446
SourceIBAED0.00863mGy/MBqformaximum740MBq=6.83mSv
99mTc-besilesomab(Scin-mun®)dosimetry
Organ ReferencedosemGy/MBq
Kidneys 0.0444
Bladderwall 0.0215
Spleen 0.0157
Heartwall 0.0118
Lungs 0.0100
Liver 0.0090
Bone 0.0080
Wholebody 0.00103
SourceImmunomedicsED0.00800mSv/MBqformaximum740MBq=5.92mSv
99mTc-sulesomab(Leukoscan®)dosimetry
Pros Cos Target Dosimetry Costperpa-ent
67Ga-citrateNolabelling,cheap,imagebacteriaandvertebralOM
Longhalf-life,poorimages,poorlyspecific,highradiaHon
Transferrin,bacteria,
acHvatedcells(Kreb’scycle)
18mSv(largebowel) 150€
111In-WBCGoodfor
inflammatoryboweldiseases
SterilebloodmanipulaHon,poorimaging
Mainlyneutrophils
9mSv(spleen) 300€
99mTc-WBCGoodforboneandjointinfecHons,goodSPECTimages
SterilebloodmanipulaHon,
bowelexcreHon,notforspondylo
Mainlyeosinophils
5.6mSv(spleen) 130€
ScinHmun®BehaveslikeWBC,easytouse,bindstogranulocytes
HighBMuptake,HAMAs
CirculaHngandinfiltraHnggranulocytes
6.8mSv(spleen) 350€
Leukoscan®NoHAMAs,imagesat1and6h,low
BMuptake
Notsurespecificity,
expertreading
Granulocytes,edema
5.9mSv(kidney) 350€
18F-FDG
1000€
Commerciallyavailableradiopharmaceu-calsforimaginginfec-on
Slide53
[18F]FDG:aglucoseanalog
Fluoro-deoxyglucoseGlucose
• CyclotronproducHonbyprotonbombardmentofenriched[15O]waterandisboundtomannosetriflateunderstereospecificSN2reacHoncondiHons- electrophilicfluorinaHonwith18F2- "nucleophilicsynthesis"
• T1/2=110min(at70%)
• F-18decaysbyβ+emission:249.8keV,96.73%perdisintegraHon
Slide54
K3
K4
Hexokinase
Glucose-6-phosphatase
[18F]FDG-1-P
Glycogen
18F-FRU-6-P
Glycolysis
[18F]FDG-6-phospho-glucono-lactone
HMP
shunt
Blood
K1
K2[18F]FDG-6P[18F]FDG
OverexpressionofglucosetransportersGLUT-1andGLUT-3
[18F]FDG
[18F]FDG:uptakeandreten-on
[18F]FDGparallelsglucosemetabolism
• Tri-exponenHaldecaycurveinarterialblood• EarlyeliminaHonphase=0.2-0.3minutes
• <33mins,about3.9%oftheinjecteddosecanbemeasuredintheurine
• <2hrspost-administraHonabout20%oftheinjecteddosefoundinthebladder
• [18F]FDGuptakeisrelatedtotheglycolyHcacHvityofcellsresponsiblefortheinflammatoryresponse
• CellsinvolvedininfecHon/inflammaHon:- acHvatedlymphocytes,neutrophils,macrophages,fibroblasts,osteoblasts,
acHvatedendothelialcells,bonemarrowcells
• EnhancedglucoseconsumpHoncanalsobetheresultofastressreacHoninresponsetocellulardamage
FDGimagingofinfec-on:Pros&Cons
Advantages• F-18:goodphysicalproperHes• FDG:goodtracerkineHcs• PET:highspaHal&contrast
resoluHongoodimagequality• CT:anatomicinformaHon• StudyduraHon:1.5–2h• ShortphysicalT1/2:lower
radiaHon• Nobloodhandling
Limita-ons• Nonspecificuptake:
• Physiologic• Malignancies• ForeignbodyreacHon
• AvailabilityandwaiHnglist• Costand[lackof]
reimbursement
[18F]FDG:biodistribu-onanddosimetry
Pros Cos Target Dosimetry Costperpa-ent
67Ga-citrateNolabelling,cheap,imagebacteriaandvertebralOM
Longhalf-life,poorimages,poorlyspecific,highradiaHon
Transferrin,bacteria,
acHvatedcells(Kreb’scycle)
18mSv(largebowel) 150€
111In-WBCGoodfor
inflammatoryboweldiseases
SterilebloodmanipulaHon,poorimaging
Mainlyneutrophils
9mSv(spleen) 300€
99mTc-WBCGoodforboneandjointinfecHons,goodSPECTimages
SterilebloodmanipulaHon,
bowelexcreHon,notforspondylo
Mainlyeosinophils
5.6mSv(spleen) 130€
ScinHmun®BehaveslikeWBC,easytouse,bindstogranulocytes
HighBMuptake,HAMAs
CirculaHngandinfiltraHnggranulocytes
6.8mSv(spleen) 350€
Leukoscan®NoHAMAs,imagesat1and6h,low
BMuptake
Notsurespecificity,
expertreading
Granulocytes,oedema
5.9mSv(kidney) 350€
18F-FDGNobloodhandling,
highqualityimages
Highcost,notreimbursed,non
specific
SeveralmetabolicallyacHvecells
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