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Physique médicale
Profs. Iacobucci, Jolivet and Nessi
Projets
Thin Time-Of-Flight PET
Thin Time-Of-Flight PET
18F-fluorodeoxyglucose (mesure l’utilisation deglucose)
Recherche préclinique
PET-SPECT-CT
Institut d’Imagerie Moléculaire Translationelle
Projets
Thin Time-Of-Flight PET Tc99m
5
a)
b)
Figure1.SimplifiedsketchoftheTCAdesign
(a)ThedesignconsistsoftheneutronproductiontargetT,themoderatorandthereflector.Molybdenumsamplesareschematicallyshownplacedonthesidesanddownstreamofthetarget.
(b)DesignoftheactivatorforthetestbeamexperimentatthePSI.Thetargetposition,dimensionsanditscladdinghavebeenadaptedtotheexistingtargetholder(equippedwithadedicatedwatercoolingcircuit).Berylliumisisolatedfromthemoderator/coolingmediumbyathinaluminiumlayertopreventberylliumgettingintothecoolingsystem.
In the 99mTc Cyclo-Activator (TCA; Figure 1a), neutrons are produced by
interactionofthecyclotronprotonbeamontheberylliumtarget.Neutronsemerging
fromthetargetaremoderatedtotheenergyrangeofinterestbyheavywater,which
simultaneously serves as cooling medium. The optimal molybdenum sample,
cylindrically shaped, is placed around the target covering a large solid angle and
enablingalargeneutronfractiontobecaptured.Additionally,thegraphitereflector
surroundingthemolybdenumsampleincreasestheprobabilityofcaptureon98Moby
Tc99m
Van Noorden, Nature 2013
5
a)
b)
Figure1.SimplifiedsketchoftheTCAdesign
(a)ThedesignconsistsoftheneutronproductiontargetT,themoderatorandthereflector.Molybdenumsamplesareschematicallyshownplacedonthesidesanddownstreamofthetarget.
(b)DesignoftheactivatorforthetestbeamexperimentatthePSI.Thetargetposition,dimensionsanditscladdinghavebeenadaptedtotheexistingtargetholder(equippedwithadedicatedwatercoolingcircuit).Berylliumisisolatedfromthemoderator/coolingmediumbyathinaluminiumlayertopreventberylliumgettingintothecoolingsystem.
In the 99mTc Cyclo-Activator (TCA; Figure 1a), neutrons are produced by
interactionofthecyclotronprotonbeamontheberylliumtarget.Neutronsemerging
fromthetargetaremoderatedtotheenergyrangeofinterestbyheavywater,which
simultaneously serves as cooling medium. The optimal molybdenum sample,
cylindrically shaped, is placed around the target covering a large solid angle and
enablingalargeneutronfractiontobecaptured.Additionally,thegraphitereflector
surroundingthemolybdenumsampleincreasestheprobabilityofcaptureon98Moby
Tc99m
• Design d’un activateur• “Irradiation studies”
• Radiochimie
Collaboration:
DPNC (UNIGE) – Université de Zürich – PSI
Roger Alberto (Université de Zürich), Maurice Bourquin, Giuseppe
Iacobucci, Renaud Jolivet, Marzio Nessi, Christiaan Etienne Vermeulen
(PSI)
Tc99m
Dr Bradley Childs
2
g
g
Scheme1.PrincipleofSzilard-Chalmersreaction.
a)Neutronirradiationof[98MoO4]2-yieldsmainly[99MoO4]2-whichcannotbeseparatedfromthetarget
material.
b)Neutronirradiationofanorganometalliccompoundyields99Mo-inachemicalformdifferentfromthe
targetmaterial,whichcannowbeseparatedbychemicalmethodsfromthetargetcompound.
generatorsdependentofafewproducers,e.g.thePettenreactorinTheNetherlands,
ChalkRiverinCanada,NECSAinSouthAfricaandafewothers.Thesereactorswillbe
shutdown in thenextyears formaintenance,orpermanently.This jeopardizesthe
productionofurgentlyneeded 99Mo/99mTcgeneratorsinclinics.6, 7Consideringthat
themarketbehindthesegeneratorsisintherangeofseveralhundredmilliondollars
peryear,findingalternativeproductionmethodsisnotonlyjustifiedfromascientific
perspectivebutalsoforcommercialreasons.Thishasbeenrecognizedespeciallyby
theUnitedStates,which investsubstantial fundsinrelatedresearchprojectsat the
Argonne National Laboratory (http://www.anl.gov/articles/scientists-develop-
affordable-way-generate-medical-isotopes).Besidethecommercialincentivebehind
novelwaysofproducing99Mofornuclearmedicine,developingcountrieshavegreat
interestinalternativemodesofpreparationsincethepresentreactorservicesarean
unsustainable economic model. For instance, India at its BARC nuclear research
centreinMumbaiusesneutronsforactivatingmolybdenumaimingatareactionto
produce99Mo/99mTcgeneratorsdirectly.
This proposal aims at developing a cheap and scientifically innovative
methodforthepreparationofthisradionuclidewithhighspecificactivity.The
Szilard-Chalmers approach as proposed herein is a long known method for
producing carrier-free radionuclides but it has not yet been applied to nuclides
relevantfornuclearmedicinepurposes.8Theobjectiveofobtaininghighlyenriched99Mobythismethodalsobypassesapproachesinwhichcyclotron-producedprotons
or deuterons are used. The latter would completely hamper the big advantage of
Projets
Thin Time-Of-Flight PET Tc99m
5
a)
b)
Figure1.SimplifiedsketchoftheTCAdesign
(a)ThedesignconsistsoftheneutronproductiontargetT,themoderatorandthereflector.Molybdenumsamplesareschematicallyshownplacedonthesidesanddownstreamofthetarget.
(b)DesignoftheactivatorforthetestbeamexperimentatthePSI.Thetargetposition,dimensionsanditscladdinghavebeenadaptedtotheexistingtargetholder(equippedwithadedicatedwatercoolingcircuit).Berylliumisisolatedfromthemoderator/coolingmediumbyathinaluminiumlayertopreventberylliumgettingintothecoolingsystem.
In the 99mTc Cyclo-Activator (TCA; Figure 1a), neutrons are produced by
interactionofthecyclotronprotonbeamontheberylliumtarget.Neutronsemerging
fromthetargetaremoderatedtotheenergyrangeofinterestbyheavywater,which
simultaneously serves as cooling medium. The optimal molybdenum sample,
cylindrically shaped, is placed around the target covering a large solid angle and
enablingalargeneutronfractiontobecaptured.Additionally,thegraphitereflector
surroundingthemolybdenumsampleincreasestheprobabilityofcaptureon98Moby
Neurophysics
Votre cerveau~20 W
iMac65 – 240 W
Age (years)
0 5 10 150
20
40
60
(%)
Kuzawa et al., PNAS 2014
‣ Le cerveau représente ~2% de la masse du corps mais ~20% de sa consommation d’énergie
Neurophysique
18F-fluorodeoxyglucose (mesure l’utilisation deglucose)
Figure 4
b
0 20 40 60 80 1000
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0 2 4 6 8 10 12
gsyn / (normal gsyn)
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gsyn / (normal gsyn)
e f
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gsyn / (normal gsyn)
d
Neurophysique
Neurophysique
• Mireille Conrad• Postdoc to be recruited• Ioanna Prionisti
Réseau de neurones artificiels
Neuromorphic chips
Bonnes Fêtes!