[Gate-users] Why Y90 has different energy distributions when using ion source and fastY90 source?

Jinxia Guo jinxia.guo2009 at gmail.com
Tue Feb 7 14:18:54 CET 2017 

Thomas,

Thank you and Jared for the remarks! I added a positron source to the ion
source as you said and got the consistent singles energy distributions
between two kinds of source setting (ion+positron and fastY90) when I came
back from my vacation.

Best,
Jinxia

2017-01-24 21:24 GMT+08:00 Carlier Thomas <thomas.carlier at chu-nantes.fr>:

> Dear all,
>
>
> We look with Jared (the developer of fast90Y) your simulation set-up.
>
> Two remarks:
>
> 1 - The ion source related to 90Y do not include the internal pair
> creation. Be aware of that because you are looking something close to the
> conventional PET energy window. So, when you want to make a comparison,
> please add a corresponding positron source to the ion source
>
> 2 - The use of the fast90Y needs to add about 5 mm of padding past the
> edges of the Y90 source so that brem could be created. Otherwise, a lot of
> electrons will be emitted in air next to the phantom. This is a small
> difference but take care of that..
>
>
> Lastly, the energy distribution of the brem used in the fast Y90 model is
> derived from the ion source simulation. Hence, it is not expected to have
> big difference between the two...
>
>
> Hope this help
>
>
> Thomas Carlier
>
> University hospital of Nantes
>
> Nuclear Medicine Dept
>
> France
>
> Le 24/01/2017 à 09:48, Jinxia Guo a écrit :
>
> Paulo,
>
> The phantom and source size didn't have effects on the energy
> distributions. I checked the physic interactions in the hits data.
> PhotonElectric, RayleighScatter and ComptonScatter were found in fastY90
> simulation. Besides these three, plenty of ElectricIonization and
> Bremsstrahlung were also found in ion source simultions. These two kinds of
> interaction in crystals may be the reason of the difference in the energy
> distributions. Maybe they were forbidden in fastY90 source.
>
>
> Anyway, thanks!
>
> Jinxia
>
> 2017-01-24 0:35 GMT+08:00 Paulo Caribé <Paulo.Caribe at ugent.be>:
>
>> Jinxia,
>>
>> make sure that your phantom and source are in the same size. Have you
>> tried it in this away?
>>
>> 1）Setting1: simulation with fastY90
>>
>> #-----------------Phantom--------------------------------
>>
>> /gate/cylinder_phantom/geometry/setHeight 30.5  cm (You should put
>>  setHeight = 30.065  cm)
>>
>> #-----------------Source--------------------------------
>>
>> /gate/source/ionsrc/gps/halfz  15.0325 cm
>>
>> ##########################################
>>
>>
>> 2）Setting2: simulation with the ion source
>>
>> #-----------------Phantom--------------------------------
>>
>> /gate/cylinder_phantom/geometry/setHeight 30.065  cm
>>
>> #-----------------Source--------------------------------
>>
>> /gate/source/ionsrc/gps/halfz  15.0325 cm
>>
>> ##########################################################
>>
>> Regards,
>>
>> Doctoral researcher
>> Ghent University - iMinds Medical IT
>> Medical Imaging and Signal Processing (MEDISIP)
>> IBiTech - Campus UZ - Entrance 36 (Block B)
>> De Pintelaan 185
>> B-9000 Gent
>> Belgium
>>
>>
>>
>> On 23 Jan 2017, at 15:30, Jinxia Guo < <jinxia.guo2009 at gmail.com>
>> jinxia.guo2009 at gmail.com> wrote:
>>
>> Hi guys,
>>
>>
>> Recently I’ve done some simulation with Y90 source in Gate7.2 develop
>> version. Two settings are with the same camera, digitizer and output but
>> respectively with normal ion source and fastY90 source.  The energy
>> distributions of singles in coincidences for each setting are shown below. It
>> seems that the energy distribution with the normal ion source is very
>> different with the fastY90 source. I thought they should be the same, but
>> why the results actually are not? Anything wrong in the simulations
>> setting? Thanks!
>>
>>
>> *The energy distributions of each setting.*
>>
>> (1)   fastY90 source (energy window: [420, inf])                (2)
>> ion source (energy window:[420, inf])
>>
>>
>>
>>
>>        (3) fastY90 source (energy window: [0, inf])
>>     (4)   ion source (energy window:[0, inf])
>>
>>
>>
>>
>> （1）Setting1: simulation with fastY90
>>
>> #-----------------Phantom--------------------------------
>>
>> /gate/world/daughters/name cylinder_phantom
>>
>> /gate/world/daughters/insert cylinder
>>
>> /gate/cylinder_phantom/setMaterial Water
>>
>> /gate/cylinder_phantom/geometry/setRmax   10  cm
>>
>> /gate/cylinder_phantom/geometry/setRmin   0  cm
>>
>> /gate/cylinder_phantom/geometry/setHeight 30.5  cm
>>
>> /gate/cylinder_phantom/placement/setTranslation 0. 0. 0. mm
>>
>> /gate/cylinder_phantom/attachPhantomSD
>>
>>
>> #-----------------Source--------------------------------
>>
>> /gate/source/addSource ionsrc fastY90
>>
>> /gate/source/ionsrc/setActivity 0.1 Ci
>>
>> /gate/source/ionsrc/useDefaultHalfLife
>>
>> /gate/source/ionsrc/gps/angtype iso
>>
>> /gate/source/ionsrc/gps/number 1
>>
>>
>> /gate/source/ionsrc/setMinBremEnergy 50 keV
>>
>> /gate/source/ionsrc/setPositronProbability 0.00003186
>>
>>
>> /gate/source/ionsrc/gps/type Volume
>>
>> /gate/source/ionsrc/gps/shape Cylinder
>>
>> /gate/source/ionsrc/gps/radius  10 cm
>>
>> /gate/source/ionsrc/gps/halfz  15.0325 cm
>>
>> /gate/source/ionsrc/gps/centre 0. 0. 0. Mm
>>
>> /gate/source/ionsrc/gps/confine cylinder_phantom
>>
>>
>> #-----------------Physics--------------------------------
>>
>> /gate/physics/addProcess Decay
>>
>> /gate/physics/addProcess RadioactiveDecay
>>
>>
>> /gate/physics/addProcess PhotoElectric
>>
>> /gate/physics/processes/PhotoElectric/setModel StandardModel
>>
>>
>> /gate/physics/addProcess Compton
>>
>> /gate/physics/processes/Compton/setModel StandardModel
>>
>>
>> /gate/physics/addProcess RayleighScattering
>>
>> /gate/physics/processes/RayleighScattering/setModel PenelopeModel
>>
>>
>> /gate/physics/addProcess ElectronIonisation
>>
>> /gate/physics/processes/ElectronIonisation/setModel StandardModel e-
>>
>> /gate/physics/processes/ElectronIonisation/setModel StandardModel e+
>>
>>
>> /gate/physics/addProcess Bremsstrahlung
>>
>> /gate/physics/processes/Bremsstrahlung/setModel StandardModel e-
>>
>> /gate/physics/processes/Bremsstrahlung/setModel StandardModel e+
>>
>>
>> /gate/physics/addProcess PositronAnnihilation
>>
>> /gate/physics/addProcess MultipleScattering e+
>>
>> /gate/physics/addProcess MultipleScattering e-
>>
>>
>> /gate/physics/setEMin 0.1 keV
>>
>> /gate/physics/setEMax 2.0 GeV
>>
>> /gate/physics/setDEDXBinning 220
>>
>> /gate/physics/setLambdaBinning 220
>>
>>
>> /gate/physics/processList Enabled
>>
>> /gate/physics/processList Initialized
>>
>>
>> （2）Setting2: simulation with the ion source
>>
>> #-----------------Phantom--------------------------------
>>
>> /gate/world/daughters/name cylinder_phantom
>>
>> /gate/world/daughters/insert cylinder
>>
>> /gate/cylinder_phantom/setMaterial Water
>>
>> /gate/cylinder_phantom/geometry/setRmax   10  cm
>>
>> /gate/cylinder_phantom/geometry/setRmin   0  cm
>>
>> /gate/cylinder_phantom/geometry/setHeight 30.065  cm
>>
>> /gate/cylinder_phantom/placement/setTranslation 0. 0. 0. mm
>>
>> /gate/cylinder_phantom/attachPhantomSD
>>
>>
>> #-----------------Source--------------------------------
>>
>> /gate/source/addSource ionsrc
>>
>> /gate/source/ionsrc/setActivity 0.10 Ci
>>
>> /gate/source/ionsrc/gps/particle ion
>>
>> /gate/source/ionsrc/gps/ion 39 90 0 0
>>
>> /gate/source/ionsrc/setForcedUnstableFlag true
>>
>> #/gate/source/ionsrc/setForcedHalfLife 230544 s
>>
>> /gate/source/ionsrc/useDefaultHalfLife
>>
>> /gate/source/ionsrc/gps/angtype iso
>>
>> /gate/source/ionsrc/gps/number 1
>>
>>
>> /gate/source/ionsrc/gps/type Volume
>>
>> /gate/source/ionsrc/gps/shape Cylinder
>>
>> /gate/source/ionsrc/gps/radius  10 cm
>>
>> /gate/source/ionsrc/gps/halfz  15.0325 cm
>>
>> /gate/source/ionsrc/gps/centre 0. 0. 0. mm
>>
>>
>> /gate/source/ionsrc/gps/confine cylinder_phantom
>>
>>
>> #-----------------Physics--------------------------------
>>
>> /gate/physics/addProcess Decay
>>
>> /gate/physics/addProcess RadioactiveDecay
>>
>>
>> /gate/physics/addProcess PhotoElectric
>>
>> /gate/physics/processes/PhotoElectric/setModel StandardModel
>>
>>
>> /gate/physics/addProcess Compton
>>
>> /gate/physics/processes/Compton/setModel StandardModel
>>
>>
>> /gate/physics/addProcess RayleighScattering
>>
>> /gate/physics/processes/RayleighScattering/setModel PenelopeModel
>>
>>
>> /gate/physics/addProcess GammaConversion
>>
>> /gate/physics/processes/GammaConversion/setModel StandardModel
>>
>>
>> /gate/physics/addProcess ElectronIonisation
>>
>> /gate/physics/processes/ElectronIonisation/setModel StandardModel e-
>>
>> /gate/physics/processes/ElectronIonisation/setModel StandardModel e+
>>
>>
>> /gate/physics/addProcess Bremsstrahlung
>>
>> /gate/physics/processes/Bremsstrahlung/setModel StandardModel e-
>>
>> /gate/physics/processes/Bremsstrahlung/setModel StandardModel e+
>>
>>
>> /gate/physics/addProcess PositronAnnihilation
>>
>> /gate/physics/addProcess MultipleScattering e+
>>
>> /gate/physics/addProcess MultipleScattering e-
>>
>>
>> /gate/physics/setEMin 0.1 keV
>>
>> /gate/physics/setEMax 2.0 GeV
>>
>> /gate/physics/setDEDXBinning 220
>>
>> /gate/physics/setLambdaBinning 220
>>
>>
>> /gate/physics/processList Enabled
>>
>> /gate/physics/processList Initialized
>>
>>
>>
>>
>>
>> Regards,
>>
>> Jinxia
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>>
>>
>>
>
>
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