1. The Hadrontherapy Geant4 advanced example
P. Cirrone, G. Cuttone, F. Di Rosa, S. Guatelli, M. G. Pia, G. Russo
4th Workshop on Geant4 Bio-medical Developments,
Geant4 Physics Validation INF Genova, July 2005
Susanna Guatelli

2. Scope of the hadrontherapy Geant4 application
Model a hadrontherapy beam line,
Donated by CATANA
Based on the CATANA beam line at INFN LNS
Calculate the energy deposit in a phantom
Dosimetry study
Scattering system
Modulator & Range shifter
Monitor chambers
Ligth field
Laser
Susanna Guatelli

3. Software process
The development of the hadrontherapy Geant4 application follows an iterative-incremental approach
Software process products:
User Requirements document
Design
Documentation about the implementation is regularly updated
Susanna Guatelli

4. The Hadrontherapy advanced example
Documentation of the example:
Code review of the example in occasion of the last Geant4 public release (7.1)
Other changes: functionality added
Susanna Guatelli

5. Design Primary particle Detector Physics List Analysis
Susanna Guatelli

6. Simulation components
Primary particles
Physics List
Detector Construction
Energy deposit
Stepping action
Analysis
Susanna Guatelli

7. Primary particles
The primary particles are protons generated with initial energy, position and direction described by Gaussian distributions
Particle type
Proton
Position
Direction
Energy
The primary particle component is provided of a messenger
It is possible to change these parameters interactively
Mean position
(x = mm, y = 0., y = 0.)
Sigma position
(0., 1. mm, 1. mm)
Mean direction
(1., 0., 0.)
Sigma position
(0., , )
Mean energy
63.45 MeV
Sigma energy
400 keV
Susanna Guatelli

8. Particles: p, d, t, α, ions, e-, e+, pions, neutrons, muons
Physics component
The user can choose:
to activate EM physics only
to add on top the hadronic physics
to activate alternative models for both EM and hadronic physics
Modularised physics component
Particles: p, d, t, α, ions, e-, e+, pions, neutrons, muons
Susanna Guatelli

9. EM Physics models
The user can choose to activate for protons the following alternative models:
Low Energy - ICRU 49,
Low Energy - Ziegler77,
Low Energy - Ziegler85,
Low Energy Ziegler 2000,
Standard
The user can choose for d, t, α, ions the alternative models:
Low Energy ICRU,
In the case of Low Energy Physics, also the nuclear stopping power is active
Susanna Guatelli

10. EM Physics models The user can choose to activate for e-:
LowEnergy EEDL,
LowEnergy Penelope,
Standard
The user can choose to activate for e+:
The user can choose to activate for gamma:
LowEnergy EPDL,
Susanna Guatelli

11. Hadronic physics Elastic scattering Inelastic scattering
Alternative approaches for p, n, pions
LEP ( E < 100 MeV) and Binary Ion model ( E > 80 MeV) for d, t, α
Neutron fission and capture
Susanna Guatelli

12. Hadronic physics list
The user can select alternative hadronic physics lists for protons, pions and neutrons
Precompound model
Binary model + Precompound model ( with all the option showed above )
Bertini model
LEP
+ default evaporation
+ GEM evaporation
+ default evaporation + Fermi Break-up
+ GEM evaporation + Fermi Break-up
Susanna Guatelli

13. Detector Construction
Detailed description of the hadrontherapy beam line in terms of geometrical components and materials
The user can change geometrical parameters of the beam line through interactive commands
The modulator is modeled
The user can rotate it between different runs
Susanna Guatelli

14. Calculation of the energy deposit
The energy deposit is calculated inside a water phantom (size: 20 mm) set in front of the hadrontherapy beam line
The phantom is gridded in 80 x 80 x 80 voxels along x, y, z axis
The energy deposit of both primary and secondary particles is collected in the voxels
Susanna Guatelli

15. Parameters Threshold of production of secondary particles: 10 * mm
Cut per region fixed in the sensitive detector: mm for all the particles involved
More accurate calculation of the energy deposit
Max step fixed for all the particles in the sensitive detector = 0.02 cm
Susanna Guatelli

16. Result of the simulation
Energy deposit in the phantom
Bragg Peak along the axis parallel to the beam line (x axis)
Energy deposit of:
secondary protons
Electrons
Gamma
Neutrons
Alpha
He3
Tritium
Deuterium
along the x axis
Proton beam x
Susanna Guatelli

17. Stepping action
The user can retrieve useful information at the level of the stepping action:
The total number of hadronic interactions of primary protons in the phantom as respect to the electromagnetic ones
Which and how many secondary ions are produced in the phantom
The energy distribution of the secondary particles produced in the phantom is retrieved
Susanna Guatelli

18. Analysis Analysis tools: AIDA 3.2 and PI 1.3.3
The output of the simulation is a .hbk file with ntuples and histograms containing the results of the simulation:
Energy deposit in the phantom
Energy deposit of secondary particles in the phantom
Energy distributions of secondary particles originated in the phantom
Susanna Guatelli

19. Future developments of the Geant4 hadrontherapy advanced example
Design iteration
How to model more efficiently the geometry of the beam line
Code review
Susanna Guatelli

20. Comments
The project of the hadrontherapy Geant4 simulation is important for
Precise dosimetry for hadrontherapy
Geant4 Physics validation
Comparison of the CATANA Bragg peak experimental measurements with simulation results
Validation of alternative Geant4 e.m. and hadronic physics models
Talk on Monday
Susanna Guatelli