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

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(%)

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

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Neurophysique

Neurophysique

• Mireille Conrad• Postdoc to be recruited• Ioanna Prionisti

Réseau de neurones artificiels

Neuromorphic chips

Bonnes Fêtes!