[Gate-users] Multiple Fields
Elia Alessio
alessio.elia at medaustron.at
Mon Sep 19 11:39:14 CEST 2016
Dear Awad,
I added some comments/answers to your questions. Please, do not forget to keep the main gate users list always in the loop. In this way everybody would be able to read and help. Hope my contribution will help.
Best,
Alessio
From: Awad Almarhaby [mailto:mph-awad at hotmail.com]
Sent: Mittwoch, 14. September 2016 16:43
To: Elia Alessio <alessio.elia at medaustron.at>
Subject: Re: Multiple Fields
Dear Elia,
Many thanks for your helpful replies and I apologize for the extra questions. In fact, I am struggling at dose calculations.
-Should I use boxes instead of cylindrical/spherical phantoms to overcome the voxelization issue?
It is not mandatory. Basically it depends on what you need to do. If for you is good enough having a box instead of a cylinder or a sphere than you can easily score dose values directly as well. On the other hand, if you really need to simulate a cylindrical/spherical object, I would recommend to score the energy deposited and from these values calculate the dose in the volume of interest.
- Should the dose be calculated using the dose output or the energy deposited file?
Again, it depends on what you want to do.
-How can I estimate the dose theoretically before running simulations? Is it based on the number of particles? If yes, then how much protons or electrons required to produce 1 Gy in medium?
Good question. Yes, dose is related to number of particles that you delivered and yes, theoretically you can estimated the number of particles that you need in order to get a wanted value in the target, but here I think it is not easy to provide a generic answer and I guess is important referring to a more specific (and easier) situation (like considering water and only protons for example). In this case, you can analytically estimate the number of particles as long as you know the water mass stopping power value and the dose area product (both at reference depth) but I do not think you can actually simulate by a MC approach the number of particles that you will get (I mean, you could.. if you wait enough..). Indeed, a typical approach is to simulate a certain number of particles (lower compare the number that you actually need but high enough to fulfill your uncertainties requirements) and then re-scale the obtained dose.
I am really sorry about inconvenience.
Best regards,
Awad
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________________________________
From: Elia Alessio <alessio.elia at medaustron.at<mailto:alessio.elia at medaustron.at>>
Sent: Wednesday, September 14, 2016 3:09 PM
To: Awad Almarhaby
Cc: gate-users at lists.opengatecollaboration.org<mailto:gate-users at lists.opengatecollaboration.org>
Subject: RE: Multiple Fields
Dear Awad,
Yes, the number of particles are divided into the number of sources you are simulating, therefore you will end up with the same dose values.
I just have a further small comment that can maybe be useful for you. I have noticed that you are directly scoring dose values into cylindrical/spherical objects. In this case, I would recommend you to enable the energy deposited flag:
/gate/actor/dose/enableEdep true
and therefore post process the dose in the volume of interest from these values. At the current status, the dose actor is taking into account your voxelized geometry for dose computation and not the real geometry of your object. This means that you could have some deviations in dose from the expected dose into cylindrical/spherical objects.
Hope this can help.
Best
Alessio
From: Gate-users [mailto:gate-users-bounces at lists.opengatecollaboration.org] On Behalf Of Awad Almarhaby
Sent: Mittwoch, 14. September 2016 11:41
To: gate-users at lists.opengatecollaboration.org<mailto:gate-users at lists.opengatecollaboration.org>
Subject: [Gate-users] Multiple Fields
Dears Gate users,
I am running an example as exercise for basic dose calculations. It consists of a cylindrical phantom (patient) contains a target treated by ONE proton PBS. Then I summed all the resulted dose in phantom and target separately (phantom 18.81 cGy, target 48.3 cGy). I run the example again with TWO beams and I got the same numbers for both dose actors. The number of primaries was the same in both simulations.
Is the primaries are split on the two beams by default? Am I on the correct way of dose calc.?
Here a copy of the main macro.
Thanks in advance,
Awad
#=====================================================
# VERBOSE and VISUALISATION
#=====================================================
/control/execute mac/verbose.mac
#/control/execute mac/visu.mac
#=====================================================
# GEOMETRY
#=====================================================
/gate/geometry/setMaterialDatabase data/GateMaterials.db
/gate/geometry/setMaterialDatabase data/patient-HUmaterials.db
# WORLD
/gate/world/setMaterial Air
/gate/world/geometry/setXLength 5.0 m
/gate/world/geometry/setYLength 5.0 m
/gate/world/geometry/setZLength 5.0 m
#/gate/world/placement/setTranslation 0 0 0 mm
# WATERCYLINDER
/gate/world/daughters/name water_cylinder
/gate/world/daughters/insert cylinder
/gate/water_cylinder/setMaterial Water
/gate/water_cylinder/geometry/setRmin 0 cm
/gate/water_cylinder/geometry/setRmax 15 cm
/gate/water_cylinder/geometry/setHeight 40 cm
/gate/water_cylinder/placement/setRotationAxis 1 0 0
/gate/water_cylinder/placement/setRotationAngle 90 deg
/gate/water_cylinder/placement/setTranslation 0.0 0.0 0.0 cm
/gate/water_cylinder/vis/setColor blue
/gate/water_cylinder/vis/forceWireframe
#Tumor
/gate/water_cylinder/daughters/name target
/gate/water_cylinder/daughters/insert sphere
/gate/target/setMaterial Water
/gate/target/geometry/setRmin 0 cm
/gate/target/geometry/setRmax 3 cm
/gate/target/placement/setTranslation 0.0 0.0 0.0 cm
/gate/target/vis/setColor red
#=====================================================
# PHYSICS
#=====================================================
/gate/physics/addPhysicsList emstandard_opt3
/gate/physics/Gamma/SetCutInRegion world 1 mm
/gate/physics/Electron/SetCutInRegion world 1 mm
/gate/physics/Positron/SetCutInRegion world 1 mm
/gate/physics/Gamma/SetCutInRegion water_cylinder 0.1 mm
/gate/physics/Electron/SetCutInRegion water_cylinder 0.1 mm
/gate/physics/Positron/SetCutInRegion water_cylinder 0.1 mm
/gate/physics/Gamma/SetCutInRegion target 0.1 mm
/gate/physics/Electron/SetCutInRegion target 0.1 mm
/gate/physics/Positron/SetCutInRegion target 0.1 mm
/gate/physics/SetMaxStepSizeInRegion world 1 mm
/gate/physics/ActivateStepLimiter proton
/gate/physics/ActivateStepLimiter deuteron
/gate/physics/ActivateStepLimiter triton
/gate/physics/ActivateStepLimiter alpha
/gate/physics/ActivateStepLimiter GenericIon
/gate/physics/ActivateStepLimiter proton
/gate/physics/ActivateStepLimiter e-
#=====================================================
# Statistics actor
#=====================================================
/gate/actor/addActor SimulationStatisticActor stat
/gate/actor/stat/saveEveryNSeconds 60
/gate/actor/stat/save output/statistics.txt
#=====================================================
# Dose Actor
#=====================================================
/gate/actor/addActor DoseActor dose
/gate/actor/dose/save output/phantom2Fields.txt
/gate/actor/dose/attachTo
water_cylinder
/gate/actor/dose/stepHitType random
/gate/actor/dose/setPosition 0 0 0 cm
/gate/actor/dose/setResolution 100 100 300
/gate/actor/dose/setSize 8 8 30 cm
/gate/actor/dose/saveEveryNSeconds 60
/gate/actor/dose/enableEdep false
/gate/actor/dose/enableUncertaintyEdep false
/gate/actor/dose/enableDose true
/gate/actor/dose/enableUncertaintyDose true
/gate/actor/dose/enableNumberOfHits false
/gate/actor/addActor DoseActor dose1
/gate/actor/dose1/save output/target2Fields.txt
/gate/actor/dose1/attachTo
target
/gate/actor/dose1/stepHitType random
/gate/actor/dose1/setPosition 0 0 0 cm
/gate/actor/dose1/setResolution 100 100 100
/gate/actor/dose1/setSize 6 6 6 cm
/gate/actor/dose1/saveEveryNSeconds 60
/gate/actor/dose1/enableEdep false
/gate/actor/dose1/enableUncertaintyEdep false
/gate/actor/dose1/enableDose true
/gate/actor/dose1/enableUncertaintyDose true
/gate/actor/dose1/enableNumberOfHits false
#=====================================
# SOURCE
#=====================================
/gate/source/addSource PBS PencilBeam
/gate/source/PBS/setPosition 0 0 -50 cm
/gate/source/PBS/setEnergy 150 MeV
/gate/source/PBS/setSigmaEnergy 0.1 MeV
/gate/source/PBS/setSigmaX 3 mm
/gate/source/PBS/setSigmaY 3 mm
/gate/source/PBS/setSigmaTheta 1 mrad
/gate/source/PBS/setSigmaPhi 1 mrad
/gate/source/PBS/setEllipseXThetaEmittance 5 mm*mrad
/gate/source/PBS/setEllipseXThetaRotationNorm positive
/gate/source/PBS/setEllipseYPhiEmittance 5 mm*mrad
/gate/source/PBS/setEllipseYPhiRotationNorm positive
/gate/source/PBS/setParticleType proton
/gate/source/PBS/setRotationAxis 1 0 0
/gate/source/PBS/setRotationAngle 0 deg
/gate/source/addSource PBS2 PencilBeam
/gate/source/PBS2/setPosition 0 0 50 cm
/gate/source/PBS2/setEnergy 150 MeV
/gate/source/PBS2/setSigmaEnergy 0.1 MeV
/gate/source/PBS2/setSigmaX 3 mm
/gate/source/PBS2/setSigmaY 3 mm
/gate/source/PBS2/setSigmaTheta 1 mrad
/gate/source/PBS2/setSigmaPhi 1 mrad
/gate/source/PBS2/setEllipseXThetaEmittance 5 mm*mrad
/gate/source/PBS2/setEllipseXThetaRotationNorm positive
/gate/source/PBS2/setEllipseYPhiEmittance 5 mm*mrad
/gate/source/PBS2/setEllipseYPhiRotationNorm positive
/gate/source/PBS2/setParticleType proton
/gate/source/PBS2/setRotationAxis 1 0 0
/gate/source/PBS2/setRotationAngle 180 deg
#=====================================================
# INITIALISATION
#=====================================================
/gate/run/initialize
#=====================================================
# START BEAMS
#=====================================================
/gate/random/setEngineName MersenneTwister
/gate/random/setEngineSeed auto
# When only using the EmCalculator actor for various configurations
# (without caring of the dose deposition)
#/gate/application/setTotalNumberOfPrimaries 1
# Otherwise
/gate/application/setTotalNumberOfPrimaries 1000000
/gate/application/start
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