[Gate-users] S-values simulation
Ashok Tiwari
tiwarias at yahoo.com
Tue Feb 9 16:49:43 CET 2021
Hi Maria,
You could start a simulation by setting a total number of primaries instead of time. Based on my experience with GATEv8.1, the transport of 20 million particles was found to provide sufficient statistical precision. See details in: The Impact of Tissue Type and Density on Dose Point Kernels for Patient-Specific Voxel-Wise Dosimetry: A Monte Carlo Investigation | Radiation Research | Allen Press
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The Impact of Tissue Type and Density on Dose Point Kernels for Patient-...
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Also, I recommend using ~1 keV energy cuts in dose point kernel simulations. Cuts can be set by using:
/gate/physics/Gamma/SetCutInRegion world ... mm/gate/physics/Electron/SetCutInRegion world ... mm
/gate/physics/Gamma/SetCutInRegion my_phantom ... mm /gate/physics/Electron/SetCutInRegion my_phantom .. mm
Another important thing is an steplimiter, you could set it by using:
/gate/physics/SetMaxStepSizeInRegion my_phantom ... mm/gate/physics/ActivateStepLimiter e-
All other infos are described in the paper.
Regards,Ashok
On Tuesday, 9 February 2021, 09:19:23 am GMT-6, Maria Inês Ribeiro <mid.ribeiro at campus.fct.unl.pt> wrote:
Thank you so much.
It was supposed to be 100000 s. I just killed the simulation because it was taking too long. I swapped to the normal ion source definition since fastY90 can't be used for dosimetry.
Do you recommend decreasing cut energy for photons and electrons?
Kind regards, Maria
陈戈飞 <xiaofeizaina at 126.com> escreveu no dia terça, 9/02/2021 à(s) 15:13:
Hi maria
The total time of your simulations is 10000s，right? If so, you only need to multiply by 1000(Gy->mGy) and divide 10000(time to 1s).
And I recommend setting cut energy for beta and photon. Default is 10 mm.
You'd better recheck the definition of fastY90. It can't be used for dose purposes.
Thank you
| | 陈戈飞 邮箱：xiaofeizaina at 126.com |
签名由 网易邮箱大师 定制
On 02/09/2021 22:38, Maria Inês Ribeiro wrote:
Hi everyone,
I am attempting to compute a dose point kernel in soft tissue for a point source of Y90. I am using the fastY90 with an activity of 1 MBq. I then ran 40.000 slices of 1 second and stored the dose.
My question is how do I convert my dose map (Gy) into the s values (mGy/(MBq.s)) for each voxel?
Here is my could in case it could help to support my question:
#===============================================================================
# GEOMETRY
#===============================================================================
/gate/geometry/setMaterialDatabase data/GateMaterials.db
#WORLD ======================================
/gate/world/setMaterial Air
/gate/world/geometry/setXLength 50 mm
/gate/world/geometry/setYLength 50 mm
/gate/world/geometry/setZLength 50 mm
#LIVER ======================================
/gate/world/daughters/name liverPhantom
/gate/world/daughters/insert box
/gate/liverPhantom/setMaterial Liver
/gate/liverPhantom/geometry/setXLength 24.31 mm
/gate/liverPhantom/geometry/setYLength 24.31 mm
/gate/liverPhantom/geometry/setZLength 24.31 mm
#===============================================================================
# PHYSICS
#===============================================================================
/gate/physics/addPhysicsList emstandard_opt3
#===============================================================================
# DETECTORS
#===============================================================================
#DOSE ACTOR ==============================
#builds 3D images of:
# - the energy deposited (edep in MeV)
# - dose deposited (Gy)
# - the number of hits in a volume
/gate/actor/addActor DoseActor VSV
/gate/actor/VSV/attachTo liverPhantom
/gate/actor/VSV/stepHitType random
/gate/actor/VSV/setSize 24.31 24.31 24.31 mm
/gate/actor/VSV/setPosition 0 0 0 cm
/gate/actor/VSV/setResolution 11 11 11
/gate/actor/VSV/enableEdep true
/gate/actor/VSV/enableUncertaintyEdep true
/gate/actor/VSV/enableSquaredEdep true
/gate/actor/VSV/enableDose true
/gate/actor/VSV/enableUncertaintyDose true
/gate/actor/VSV/enableSquaredDose true
/gate/actor/VSV/enableNumberOfHits true
/gate/actor/VSV/save output/VSV.mhd
#SIMULATION STATISTIC =====================
#this actos counts the number of steps, tracks, events, runs in the simulation
/gate/actor/addActor SimulationStatisticActor stat
/gate/actor/stat/save output/stat-VSV.txt
/gate/actor/stat/saveEveryNSeconds 60
#===============================================================================
# INITIALISATION
#===============================================================================
/gate/run/initialize
/gate/random/setEngineName MersenneTwister
/gate/random/setEngineSeed auto
#===========================================================
# SOURCE
#===========================================================
# fastY90
/gate/source/addSource y90 fastY90
/gate/source/y90/setActivity 1. MBq
#=====================================================
# START
#=====================================================
/gate/application/setTimeSlice 1. s
/gate/application/setTimeStart 0. s
/gate/application/setTimeStop 1000000. s
/gate/application/start
Thanks a lot for your attention,
Maria Inês
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