1. GATE Monte Carlo simulation platform
Lydia MAIGNE
Laboratoire de Physique Corpusculaire, Clermont-Fd
CNRS/IN2P3

2. Medical physics simulations
PET camera
Ocular brachytherapy treatment
Radiotherapy
OpenGATE collaboration

3. The birth of GATE
July 2001
Concept proposed by C. Morel at the « Monte Carlo in nuclear medicine workshop » organised by I.Buvat in Paris
Autumn 2001
First specification documents
Initiation of developments
December 2001
First collaboration meeting
Participants : University of Lausanne, University of Geneva, LPC Clermont-Ferrand IN2P3
May 2002
OpenGATE public meeting
May 2004: First Gate release
May 2009: Gate version 4.0.0
June 2009: GATE version for nuclear medicine and radiotherapy
June 2010: GATE version with improved RT features and CT imaging
March 2010: GATE version (new hadronic processes)

4. The OpenGATE collaboration
Current status
20 groups
Fields: SPECT, PET, µPET, radiotherapy, hadrontherapy
All members contribute
According to their interest and know-how
OpenGATE meetings: 2/3 per year
Coordination
Irène BUVAT, spokesman
Sébastien JAN, technical coordinator
Jan S et al, GATE V6: a major enhancement of the GATE simulation platform enabling modelling of CT and radiotherapy.
Phys. Med. Biol. 56 (2011)
CRUMP INSTITUTE FOR
MOLECULA IMAGING

5. How it works Based on Geant4: version 4.9.3 & 4.9.4
C++ object oriented langage
Reliable cross sections
Core layer: C++ classes close to the G4 kernel
GATE development: C++ classes derived from the core layer classes
modelisation of detectors, sources, patient
movement (detector, patient)
time-dependent processes (radioactive decay, movement management, biological kinetics)
Ease of use
Command scripts to define all the parameters of the simulation (geometry construction, specification of physical processes, sources)
User interface
Application layer
Core layer
Geant4

6. GATE architecture GATE 6.1 Geometry/ General/ Physics/ Digit_hits/
GateClock,GateHounsfield,
GateIDFilter,
GateParticleFilter,
GatePrimaryGeneratorAction,
GateRunManager....
CLHEP
Geometry/
GateBox, GateCylinder... GateGeometryVoxel, GateImageNestedParametrisation, GateImageRegionalized,
GateCPETSystem.cc, GateCylindricalPETSystem.cc, GatePETScannerSystem.cc, GateScannerSystem.cc,
ROOT 5.24
Physics/
GateBremsstrahlung, GateElectronionisation, GateHadron..., GateCompton..., GatePhotoelectric..., GateRayleigh, GatePositron....
GEANT4.9.3 &
GEANT4 9.4
Digit_hits/
GateActor, GateCrystalHit, GateCrystalSD, GateDoseActor, GateKillActor, GateToAscii, GateToRoot, GateToInterfile, GateToSinogram...
GEANT4 Data
G4EMLOW6.2
G4NDL-3.13
PhotonEvaporation-2.0
G4RadioactiveDecay-3.2
G4ABLA-3.0
ELASTIC-1.1

7. Physics processes EM processes
Standard and low energy EM processes available
Photoelectric, compton scattering, Rayleigh scattering, pair production
Ionization (for e-, e+, hadrons, ions..)
Bremsstrahlung, positron and e- anihilation, single and multiple scattering
Hadronic processes
Elastic scattering
Inelastic process for proton
Inelastic process for ion
Pions
Neutrons
Radiative capture
Inelastic scattering
Fission
Particle decay
Radioactive decay

8. GATE for medical imaging
IMNC-IN2P3 (CNRS UMR 8165)
Simulation of the MOBY phantom in a PET/CT ImXgam prototype
Simulation of a FDG PET of a whole body scan as aquired on a GEMINI GXL PET scanner
XCAT simulation
Clinical scan (PET, SPECT, CT)

9. Systems for scans Scanner SPECTHead PET-ECAT scan CylindricalPET CPET
CTscan
CTscanner
scanner
SPECThead
ecat
cylindricalPET
CPET
module
level1
crystal
block
rsector
crystal
cluster
level2
pixel
crystal
module
pixel
level3
crystal
level4
layer0
level5
layer1

10. PET-MR camera: Key Jo Hong, Yong Choi

11. Fields of research in nuclear medicine
Caracterization of detector efficiency
Caracterization of medical scans and small animal scans
Molecular imaging
Quantification
Dosimetry (low energy)
Computing time efficiency

12. GATE for radiation therapy
All linac geometry possible
Advanced features with dedicated scorer (actors)
doseDistributionActor, KillActor, PhaseSpaceActor
Variance reduction technique
Voxelized phantom/patient
Output = Images in ROOT or Analyze format of:
The dose distribution
The statitistical uncertainty
The number of hits in each voxels…

13. Variance reduction technique
The weight of secondary particles is recalculated in function of the number of secondaries generated. User can also define filters to increase the efficiency of these techniques.
Splitting
to split 100 times the electron bremsstrahlung photon
Russian roulette
Russian roulette is played on secondary particles. The survival probability is 1/N and the weight of each secondary is N.
Selective splitting and russian roulette
user can add selections criteria on the incident (primary) or secondary particles. The selection is done with filters

14. Regionalized Volume (RV)
CT images are segmented into multiple homogeneous regions (with no density gradient greater than a user specified threshold)
A first image of homogeneous regions is created : RV image
A voxelized image describing the patient is created and associated to the RV image
The particles are tracked in the RV image, the dose scored in the voxelized image
Less boundaries, less steps, gain of CPU time
D. Sarrut et al. Med Phys 35, April 2008
Representation with PV
GATE example :
1 million 6MV photons
Field 5x5 cm²
one CPU 2.33 GHz
NPV RV
40 materials
13.5 min
5.1 min
7 materials
2.5 min
Representation with RV
CT image

15. Fields of research in radiation therapy
Validation
Dosimetry (10 keV to 20 MeV)
Standard and Low energy G4 packages
Linac modelling + treatment plans
New techniques: IMRT, IGRT, cyberknife, pencil beam
Computing time efficiency (grid): GateLab
Radiobiology
Bacteria survivals (E. Coli), human cell survivals
DNA repare

16. GATE for hadron therapy
In France 2 projects:
ARCHADE: European centre for R&D
Located in Caen
Partnership with IBA company
Cyclotron for acceleration of protons and carbon ions
Research in physics and radiobiology and then patients
ETOILE: treatment of patients (2015)
Located in Lyon
Collaborations with IBA company on protontherapy applications

17. Fields of research in hadron therapy
Online beam imaging to control the dose during the treatment
Novel in beam PET, in vivo tumour response imaging
Innovative gantry designs
Detectors & electronics:
Silicium PM, MCPPMT
Dosimetry
Validation of physic processes
Validation of treatment plans
Radiobiology
Cell survival, DNA repare
GSI Darmstat
European NoVel Imaging
Systems for ION therapy

18. GEANT4/GATE and Grid tutorial – Seoul July 2010
~50 participants
NCC, Samsung Medical Center…
Strong interest by the medical physics community of Seoul for radiation therapy and medical imaging applications
Involvment in new collaborations
Protontherapy applications (treatment plans, validation): future collaboration with NCC
Radiobiology
GEANT4-DNA & GATE: multi-scales approach

19. Next step: Multi-scale simulations GATE-G4DNA
Nano scale: LPC-CENBG (G4 DNA)
Modelling the DNA, DNA strand breaks, DNA repair, validation
Trung Quang PHAM ( )
Micro scale: LPC-LIMOS
Cell survival after radiation
modelling
Benjamin Louvet ( )
Macro scale: GATE collaboration
Dose to human tissue, organs
GATE collaboration
Yann Perrot ( )
3 PhD students in our group working on the 3 levels of simulation