[Gate-users] Dose actor voxel precision issue
Eng. M Pharaon
pharaon_m at hotmail.com
Sat May 30 21:29:31 CEST 2020
Dear Matthew
What type of dose actor you are using ? Because I'm facing a problem with dose by region actor and my whole project is depending on solving this problem so I could have accurate results .
When I use this actor on low energies, such as 0.01 Mev , the deposited energy results are good and I could confirm from mhd output file that all the energy has been located in the source origin.
But when I use energies for example from 0.3 to 2 Mev, I get results lower than they should be compared to the same voxel phantom results that has been simulated using mcnp code,
Could that be the same problem you faced?or you suggest different things to check?
Below you can check the macrofiles I am using
#/control/execute verbose.mac
#/control/execute ../mac/visu.mac
#==============================
# GEOMETRY
#==============================
/gate/geometry/setMaterialDatabase ../data/GateMaterials.db
#----------------------
# World
#----------------------
/gate/world/geometry/setXLength 300 cm
/gate/world/geometry/setYLength 300 cm
/gate/world/geometry/setZLength 300 cm
/gate/world/setMaterial Air
/gate/world/vis/setVisible 0
# Body
/gate/world/daughters/name phantom
/gate/world/daughters/insert ImageNestedParametrisedVolume
/gate/phantom/geometry/setImage ../data/Segm.mhd
/gate/phantom/geometry/setRangeToMaterialFile ../data/range_geo.dat
#==============================
# PHYSICS
#==============================
#----------------------
# Physics List
#----------------------
/gate/physics/addPhysicsList emlivermore
#----------------------
# Cuts and Step limiters
#----------------------
/gate/physics/Electron/SetCutInRegion world 0.01 mm
/gate/physics/Gamma/SetCutInRegion world 0.01 mm
/gate/physics/Electron/SetCutInRegion phantom 0.001 mm
/gate/physics/Gamma/SetCutInRegion phantom 0.001 mm
/gate/physics/SetMaxStepSizeInRegion phantom 0.001 mm
/gate/physics/ActivateStepLimiter e-
/gate/physics/displayCuts
#########/gate/physics/addPhysicsList emlivermore
#########/gate/physics/Gamma/SetCutInRegion world 10.0 mm
##########/gate/physics/Electron/SetCutInRegion world 10.0 mm
##########/gate/physics/Positron/SetCutInRegion world 10.0 mm
##########/gate/physics/Gamma/SetCutInRegion phantom 0.1 mm
##########/gate/physics/Electron/SetCutInRegion phantom 0.1 mm
##########/gate/physics/Positron/SetCutInRegion phantom 0.1 mm
#==============================
# DETECTORS
#==============================
# It is possible to save a DoseActor as a 3D matrix.
/gate/actor/addActor DoseActor dose3D
/gate/actor/dose3D/attachTo phantom
/gate/actor/dose3D/stepHitType random
/gate/actor/dose3D/setResolution 1346 693 147
/gate/actor/dose3D/enableDose true
/gate/actor/dose3D/save ../output/output.mhd
/gate/actor/dose3D/inputDoseByRegions ../data/Segm.mhd
/gate/actor/dose3D/outputDoseByRegions ../output/DoseByRegions.txt
#==============================
# INITIALISATION
#==============================
/gate/run/initialize
#==============================
# BEAM
#==============================
# Source
/gate/source/addSource phantom voxel
# DECLARATION THAT THE VOXELIZED SOURCE WILL BE ENTERED USING IMAGE DATA
/gate/source/phantom/reader/insert image
/gate/source/phantom/imageReader/translator/insert range
/gate/source/phantom/imageReader/rangeTranslator/readTable ../data/ActivityRange.dat
/gate/source/phantom/imageReader/rangeTranslator/describe 1
# THE FOLLOWING LINE ALLOWS YOU TO INSERT THE IMAGE DATA USING THE APPROPRIATE EXTENSION FILE
/gate/source/phantom/imageReader/readFile ../data/Segm.mhd
# THE DEFAULT POSITION OF THE VOXELIZED SOURCE IS IN THE 1ST QUARTER
# SO THE VOXELIZED SOURCE HAS TO BE SHIFTED OVER HALF ITS DIMENSION IN THE NEGATIVE DIRECTION ON EACH AXIS
/gate/source/phantom/setPosition -673 -346.5 -73.5 mm
# THE FOLLOWING LINES CHARACTERIZE THE SIZE (NO DIFFERENCE WITH AN ANALYTICAL SOURCE)
/gate/source/phantom/gps/particle gamma
/gate/source/phantom/gps/energytype Mono
/gate/source/phantom/gps/monoenergy 0.1 MeV
/gate/source/phantom/gps/angtype iso
#==============================
#==============================
# START SIMULATION
#==============================
/gate/random/setEngineName MersenneTwister
/gate/random/setEngineSeed auto
/gate/application/setTotalNumberOfPrimaries 1000
/gate/application/start
==============================================================
#activity range file
1
135 135 1
Best Regards
Eng. Pharaon
===================
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________________________________
From: Gate-users <gate-users-bounces at lists.opengatecollaboration.org> on behalf of Matthew Strugari <matthew.strugari at dal.ca>
Sent: Tuesday, May 26, 2020 4:38:17 PM
To: gate-users at lists.opengatecollaboration.org <gate-users at lists.opengatecollaboration.org>
Subject: [Gate-users] Dose actor voxel precision issue
Hi all,
When using the dose actor with sub-mm voxels, I notice issues with the floating point precision of the Offset and ElementSpacing stored in the output mhd files:
Offset = -25.440999999999999 -25.440999999999999 -26.25
ElementSpacing = 0.49399998784065247 0.49399998784065247 1.5
Which are based on my settings:
/gate/actor/dose1/setSize 50.882 50.882 52.5 mm
/gate/actor/dose1/setVoxelSize 0.494 0.494 1.5 mm
I have been ignoring this and manually overwriting the header files since the difference is insignificant but it would be nice to avoid having to do that. Has anyone else experienced this issue?
Cheers,
Matthew
--
Matthew Strugari
Biomedical Translational Imaging Centre - BIOTIC,
5890 University Ave,
Halifax, NS, B3K 6R8
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