[Gate-users] Why do output file positron nuclides get deposited in the air

[hao qiushi]

I simulated the process of radiotherapy in mice by using mouse CT files. In the figure, the position of 14mm is the position where the beam enters the mouse body, and before that, it was air. What I don't understand is why some positron nuclides have higher activity values before they are injected into the mouse body.Can anyone help me.
[cid:8fdc6d6c-ad29-4e5a-a524-098d1613bd66]
My macro file:

/control/execute /home/bishe3/Desktop/gate/c200mouse/mac/verbose.mac
#/control/execute mac/visu.mac

/gate/geometry/setMaterialDatabase       /home/bishe3/Desktop/gate/c200mouse/data/GateMaterials.db

# World =======================

/gate/world/geometry/setXLength 2 m
/gate/world/geometry/setYLength 2 m
/gate/world/geometry/setZLength 2 m
/gate/world/setMaterial         Air

# geomerty ===================

/gate/HounsfieldMaterialGenerator/SetMaterialTable                  /home/bishe3/Desktop/gate/c200mouse/data/Schneider2000MaterialsTable.txt
/gate/HounsfieldMaterialGenerator/SetDensityTable                   /home/bishe3/Desktop/gate/c200mouse/data/Schneider2000DensitiesTable.txt
/gate/HounsfieldMaterialGenerator/SetDensityTolerance               0.1 g/cm3
/gate/HounsfieldMaterialGenerator/SetOutputMaterialDatabaseFilename /home/bishe3/Desktop/gate/c200mouse/data/patient-HUmaterials.db
/gate/HounsfieldMaterialGenerator/SetOutputHUMaterialFilename       /home/bishe3/Desktop/gate/c200mouse/data/patient-HU2mat.dat
/gate/HounsfieldMaterialGenerator/Generate

/gate/world/daughters/name                        mouse
/gate/world/daughters/insert                      ImageNestedParametrisedVolume
/gate/mouse/geometry/setImage                      /home/bishe3/Desktop/gate/c200mouse/data/ct_data/ct_380x992x208.hdr
/gate/geometry/setMaterialDatabase                /home/bishe3/Desktop/gate/c200mouse/data/patient-HUmaterials.db
/gate/mouse/geometry/setRangeToMaterialFile        /home/bishe3/Desktop/gate/c200mouse/data/patient-HU2mat.dat
/gate/mouse/geometry/setHUToMaterialFile           /home/bishe3/Desktop/gate/c200mouse/data/patient-HU2mat.dat

# PHYSICS=========

/gate/physics/addPhysicsList            QGSP_BIC_HP_EMZ

/gate/physics/Gamma/SetCutInRegion      world 10 mm
/gate/physics/Electron/SetCutInRegion   world 10 mm
/gate/physics/Positron/SetCutInRegion   world 10 mm

/gate/physics/Gamma/SetCutInRegion      mouse 1 mm
/gate/physics/Electron/SetCutInRegion   mouse 1 mm
/gate/physics/Positron/SetCutInRegion   mouse 1 mm

# output===================

/gate/actor/addActor                               DoseActor  doseDistribution
/gate/actor/doseDistribution/save                  /home/bishe3/Desktop/gate/c200mouse/output/output-C200.txt
/gate/actor/doseDistribution/attachTo         mouse
#/gate/actor/doseDistribution/setSize              38 99.2 20.8 mm
/gate/actor/doseDistribution/stepHitType           random
/gate/actor/doseDistribution/setPosition           0 0 0 cm
/gate/actor/doseDistribution/setResolution         380 992 208
#/gate/actor/doseDistribution/enableEdep            true
/gate/actor/doseDistribution/enableDose            true
/gate/actor/doseDistribution/enableNumberOfHits    true

/gate/actor/addActor                                   DoseActor  doseDistribution_txt
/gate/actor/doseDistribution_txt/save                  /home/bishe3/Desktop/gate/c200mouse/output/output-C200_y.txt
/gate/actor/doseDistribution_txt/attachTo              mouse
#/gate/actor/doseDistribution_txt/setSize              38 99.2 20.8 mm
/gate/actor/doseDistribution_txt/stepHitType           random
/gate/actor/doseDistribution_txt/setPosition           0 0 0 cm
/gate/actor/doseDistribution_txt/setResolution         1 992 1
#/gate/actor/doseDistribution_txt/enableEdep            true
/gate/actor/doseDistribution_txt/enableDose            true
/gate/actor/doseDistribution_txt/enableNumberOfHits    true

# ProductionAndStoppingActor==================

/gate/actor/addActor                     ProductionAndStoppingActor    prdandstp_11
/gate/actor/prdandstp_11/save               /home/bishe3/Desktop/gate/c200mouse/output/product_stop11_3D.txt
/gate/actor/prdandstp_11/attachTo           mouse
/gate/actor/prdandstp_11/setResolution      380 992 208
/gate/actor/prdandstp_11/stepHitType        random

/gate/actor/addActor                     ProductionAndStoppingActor    prdandstp_10
/gate/actor/prdandstp_10/save               /home/bishe3/Desktop/gate/c200mouse/output/product_stop10_3D.txt
/gate/actor/prdandstp_10/attachTo           mouse
/gate/actor/prdandstp_10/setResolution      380 992 208
/gate/actor/prdandstp_10/stepHitType        random

/gate/actor/addActor                     ProductionAndStoppingActor    prdandstp_15
/gate/actor/prdandstp_15/save               /home/bishe3/Desktop/gate/c200mouse/output/product_stop15_3D.txt
/gate/actor/prdandstp_15/attachTo           mouse
/gate/actor/prdandstp_15/setResolution      380 992 208
/gate/actor/prdandstp_15/stepHitType        random

/gate/actor/addActor                     ProductionAndStoppingActor    prdandstp_11_txt
/gate/actor/prdandstp_11_txt/save               /home/bishe3/Desktop/gate/c200mouse/output/product_stop11.txt
/gate/actor/prdandstp_11_txt/attachTo           mouse
/gate/actor/prdandstp_11_txt/setResolution      1 992 1
/gate/actor/prdandstp_11_txt/stepHitType        random

/gate/actor/addActor                     ProductionAndStoppingActor    prdandstp_10_txt
/gate/actor/prdandstp_10_txt/save               /home/bishe3/Desktop/gate/c200mouse/output/product_stop10.txt
/gate/actor/prdandstp_10_txt/attachTo           mouse
/gate/actor/prdandstp_10_txt/setResolution      1 992 1
/gate/actor/prdandstp_10_txt/stepHitType        random

/gate/actor/addActor                     ProductionAndStoppingActor    prdandstp_15_txt
/gate/actor/prdandstp_15_txt/save               /home/bishe3/Desktop/gate/c200mouse/output/product_stop15.txt
/gate/actor/prdandstp_15_txt/attachTo           mouse
/gate/actor/prdandstp_15_txt/setResolution      1 992 1
/gate/actor/prdandstp_15_txt/stepHitType        random

/gate/actor/addActor                      SimulationStatisticActor stat
/gate/actor/stat/save                     /home/bishe3/Desktop/gate/c200mouse/output/stat-C100.txt
/gate/actor/stat/saveEveryNSeconds        10

# filtter====================

/gate/actor/prdandstp_11/addFilter                     particleFilter
/gate/actor/prdandstp_11/particleFilter/addParticleZ      6
/gate/actor/prdandstp_11/particleFilter/addParticleA      11

/gate/actor/prdandstp_10/addFilter                     particleFilter
/gate/actor/prdandstp_10/particleFilter/addParticleZ      6
/gate/actor/prdandstp_10/particleFilter/addParticleA      10

/gate/actor/prdandstp_15/addFilter                     particleFilter
/gate/actor/prdandstp_15/particleFilter/addParticleZ      8
/gate/actor/prdandstp_15/particleFilter/addParticleA      15

/gate/actor/prdandstp_11_txt/addFilter                     particleFilter
/gate/actor/prdandstp_11_txt/particleFilter/addParticleZ      6
/gate/actor/prdandstp_11_txt/particleFilter/addParticleA      11

/gate/actor/prdandstp_10_txt/addFilter                     particleFilter
/gate/actor/prdandstp_10_txt/particleFilter/addParticleZ      6
/gate/actor/prdandstp_10_txt/particleFilter/addParticleA      10

/gate/actor/prdandstp_15_txt/addFilter                     particleFilter
/gate/actor/prdandstp_15_txt/particleFilter/addParticleZ      8
/gate/actor/prdandstp_15_txt/particleFilter/addParticleA      15
# INITIALISATION============

/gate/run/initialize
#/gate/physics/processList Available
#/gate/physics/processList Enabled

# BEAMS==================

/gate/source/addSource                         mybeam  PencilBeam
#/gate/source/mybeam/setParticleType            proton
/gate/source/mybeam/setParticleType            GenericIon
/gate/source/mybeam/setIonProperties           6 12 6 0
/gate/source/mybeam/setEnergy                  1080 MeV
/gate/source/mybeam/setSigmaEnergy             2 MeV
/gate/source/mybeam/setPosition                0 -70 1.6 mm
/gate/source/mybeam/setRotationAxis            1 0 0
/gate/source/mybeam/setRotationAngle           -90 deg
/gate/source/mybeam/setSigmaX                  2 mm
/gate/source/mybeam/setSigmaY                  2 mm
/gate/source/mybeam/setSigmaTheta              0.01 mrad
/gate/source/mybeam/setSigmaPhi                0.01 mrad
/gate/source/mybeam/setEllipseXThetaEmittance  0.01 mm*mrad
/gate/source/mybeam/setEllipseYPhiEmittance    0.01 mm*mrad

# JamesRandom Ranlux64 MersenneTwister
/gate/random/setEngineName MersenneTwister
/gate/random/setEngineSeed auto

/gate/application/noGlobalOutput
#/gate/application/readTimeSlicesIn               data/timeslice.dat
#/gate/application/readNumberOfPrimariesInAFile   data/primary.dat
/gate/application/setTotalNumberOfPrimaries       1000000
/gate/application/start
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