<div dir="ltr"><div><div><div><div>When I originally encountered the problem while simulating just the LSO contribution to a PET system, I noticed that there was only a single peak around 300 keV, and none near 200 keV. I wrote a test simulation, attached, with not detector, but that simulates a single decay of Lu176. If you look at the verbose output produced with v7.0 vs. v7.1, the difference in the decay is apparent. I've excerpted the relevant portions of the output below.<br><br></div>GATE 7.0<br>========================================================================<br><br>*********************************************************************************************************<br>* G4Track Information: Particle = Hf176[597.0], Track ID = 2, Parent ID = 1<br>*********************************************************************************************************<br><br>Step# X(mm) Y(mm) Z(mm) KinE(MeV) dE(MeV) StepLeng TrackLeng NextVolume ProcName<br> 0 0 0 0 1.96e-06 0 0 0 world_phys initStep<br> 1 -0.000751 -0.000973 0.000396 0 1.96e-06 0.00129 0.00129 world_phys ionIoni<br> 2 -0.000751 -0.000973 0.000396 0 0 0 0.00129 world_phys RadioactiveDecay<br> :----- List of 2ndaries - #SpawnInStep= 2(Rest= 2,Along= 0,Post= 0), #SpawnTotal= 2 ---------------<br> : -0.000751 -0.000973 0.000396 0 Hf176[290.2]<br> : -0.000751 -0.000973 0.000396 0.307 gamma<br> :----------------------------------------------------------------- EndOf2ndaries Info ---------------<br><br>*********************************************************************************************************<br>* G4Track Information: Particle = Hf176[290.2], Track ID = 12, Parent ID = 2<br>*********************************************************************************************************<br><br>Step# X(mm) Y(mm) Z(mm) KinE(MeV) dE(MeV) StepLeng TrackLeng NextVolume ProcName<br> 0 -0.000751 -0.000973 0.000396 0 0 0 0 world_phys initStep<br> 1 -0.000751 -0.000973 0.000396 0 0 0 0 world_phys RadioactiveDecay<br> :----- List of 2ndaries - #SpawnInStep= 2(Rest= 2,Along= 0,Post= 0), #SpawnTotal= 2 ---------------<br> : -0.000751 -0.000973 0.000396 0 Hf176[88.4]<br> : -0.000751 -0.000973 0.000396 0.202 gamma<br> :----------------------------------------------------------------- EndOf2ndaries Info ---------------<br>*********************************************************************************************************<br>* G4Track Information: Particle = Hf176[88.4], Track ID = 14, Parent ID = 12<br>*********************************************************************************************************<br><br>Step# X(mm) Y(mm) Z(mm) KinE(MeV) dE(MeV) StepLeng TrackLeng NextVolume ProcName<br> 0 -0.000751 -0.000973 0.000396 0 0 0 0 world_phys initStep<br> 1 -0.000751 -0.000973 0.000396 0 0 0 0 world_phys RadioactiveDecay<br> :----- List of 2ndaries - #SpawnInStep= 5(Rest= 5,Along= 0,Post= 0), #SpawnTotal= 5 ---------------<br> : -0.000751 -0.000973 0.000396 0 Hf176[0.0]<br> : -0.000751 -0.000973 0.000396 0.00162 e-<br> : -0.000751 -0.000973 0.000396 0.00789 gamma<br> : -0.000751 -0.000973 0.000396 0.0559 gamma<br> : -0.000751 -0.000973 0.000396 0.0231 e-<br> :----------------------------------------------------------------- EndOf2ndaries Info ---------------<br><br><br><br></div>GATE 7.1<br>===========================================================================<br><br>*********************************************************************************************************<br>* G4Track Information: Particle = Hf176[596.820], Track ID = 2, Parent ID = 1<br>*********************************************************************************************************<br><br>Step# X(mm) Y(mm) Z(mm) KinE(MeV) dE(MeV) StepLeng TrackLeng NextVolume ProcName<br> 0 0 0 0 2.88e-07 0 0 0 world_phys initStep<br> 1 -9.46e-309 -3.16e-309 -9.73e-309 0 2.88e-07 1.39e-308 1.39e-308 world_phys RadioactiveDecay<br> :----- List of 2ndaries - #SpawnInStep= 3(Rest= 0,Along= 0,Post= 3), #SpawnTotal= 3 ---------------<br> : -9.46e-309 -3.16e-309 -9.73e-309 0 Hf176<br> : -9.46e-309 -3.16e-309 -9.73e-309 0.29 gamma<br> : -9.46e-309 -3.16e-309 -9.73e-309 0.307 gamma<br> :----------------------------------------------------------------- EndOf2ndaries Info ---------------<br><br><br></div>Jared<br><br></div>============================Lu176_test.mac===================================<br><div># VISUALIZATION<br>/vis/open OGLSX<br>/vis/viewer/reset<br>/vis/viewer/set/viewpointThetaPhi 20 30<br>/vis/viewer/set/style surface<br>/vis/drawVolume<br><br>/tracking/storeTrajectory 1<br>/vis/scene/endOfEventAction accumulate<br>/vis/viewer/update<br><br>/vis/scene/add/trajectories<br><br>/gate/geometry/setMaterialDatabase GateMaterials.db<br><br># WORLD<br>/gate/world/geometry/setXLength 4. cm<br>/gate/world/geometry/setYLength 4. cm<br>/gate/world/geometry/setZLength 4. cm<br>/gate/world/setMaterial Air<br>/gate/world/vis/forceWireframe<br><br>/gate/geometry/rebuild<br><br># PHYSICS<br>/gate/physics/addPhysicsList emstandard_opt3<br>/gate/physics/addProcess RadioactiveDecay GenericIon<br>#/gate/physics/addProcess IonIonisation GenericIon<br><br># INITIALIZATION<br>/gate/run/initialize<br><br>/gate/source/addSource Lu176<br>/gate/source/Lu176/setActivity 1 Bq<br>/gate/source/Lu176/gps/particle ion<br>/gate/source/Lu176/gps/ion 71 176 0 0<br>/gate/source/Lu176/gps/energytype Mono<br>/gate/source/Lu176/gps/energy 0 MeV<br>/gate/source/Lu176/gps/type Point<br>/gate/source/Lu176/gps/centre 0. 0. 0. cm<br>/gate/source/Lu176/gps/angtype iso<br><br># OUTPUT<br>/gate/output/allowNoOutput<br><br>/tracking/verbose 2<br><br>/gate/random/setEngineName MersenneTwister<br>/gate/random/setEngineSeed auto<br><br>/gate/application/SetNumberOfPrimariesPerRun 1<br>/gate/application/start<br><br>===========================================================================<br></div></div><div class="gmail_extra"><br><div class="gmail_quote">2015-09-15 11:16 GMT+02:00 Pietrzyk, Uwe <span dir="ltr"><<a href="mailto:u.pietrzyk@fz-juelich.de" target="_blank">u.pietrzyk@fz-juelich.de</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div style="word-wrap:break-word">
<div><br>
</div>
Hi Jared,
<div><br>
</div>
<div>let me briefly ask what the detector looked like?</div>
<div>Since there are emission lines of 202 and 88 keV, the 290 keV</div>
<div>is likely to be a "summation peak”.</div>
<div><br>
</div>
<div>I have checked the RadioactiveDecay in 7.1 for our EduGATE</div>
<div>examples and did not find anything wrong. So I am a little bit</div>
<div>puzzled by the statements in your eMail.</div>
<div><br>
</div>
<div>Kind regards,</div>
<div><br>
</div>
<div>Uwe Pietrzyk</div>
<div><br>
<div>
<div><span>/----------------------------------------------------------------------</span></div>
<div>Prof. Dr. Uwe Pietrzyk<br>
Diplom-Physiker<br>
Institut für Neurowissenschaften und Medizin / INM-4<br>
Forschungszentrum Jülich GmbH<br>
52425 Jülich<br>
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&<br>
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<br>
<div><div><div class="h5">
<div>On 15 Sep 2015, at 11:05, Jared Strydhorst <<a href="mailto:jared.strydhorst@gmail.com" target="_blank">jared.strydhorst@gmail.com</a>> wrote:</div>
<br>
</div></div><blockquote type="cite"><div><div class="h5">
<div dir="ltr">
<div>
<div>If you're using RadioactiveDecay with GATE 7.1, there is a bug in Geant4 v10.1.1 that causes the emissions from the nuclear de-excitation to be simulated incorrectly. For example, I've found that after Lu-176 decays to Hf-176, it emits a 307 keV gamma,
correctly, but then goes to the ground state by emitting an unphysical 290 keV gamma, instead of a 202 keV followed by a 88 keV gamma, or the competing conversion electrons. I don't know how other isotopes are affected, though it seems from the relevant Geant4
forum that the problem isn't specific to Hf de-excitation.<br>
<br>
</div>
The bug has been fixed in G4 v10.2 (still in beta), and doesn't seem to be present in earlier versions, so if you use GATE 7.0 or earlier it shouldn't affect you.<br>
<br>
</div>
<span style="font-size:10pt" dir="ltr"><font size="1"><span style="font-size:13px"><font size="2"><span style="font-size:10pt">Jared STRYDHORST<br>
<br>
<div style="margin:0px"><span lang="fr"><font face="Cambria,serif">Laboratoire Imagerie Moléculaire In Vivo (IMIV)</font><font face="Cambria,serif"><br>
UMR 1023 Inserm/CEA/Université Paris Sud - ERL 9218 CNRS</font></span></div>
<div style="margin:0px"><span lang="fr"><font face="Cambria,serif">CEA/I2BM/Service Hospitalier Frédéric Joliot</font></span></div>
<div style="margin:0px"><span lang="fr"><font face="Cambria,serif">4, place du Général Leclerc</font><font face="Cambria,serif"><br>
91401 ORSAY Cedex</font><font face="Cambria,serif"><br>
</font></span></div>
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