1. The Geant4 Hadrontherapy Advanced Example
Developed by:
G.A.P. Cirrone1, F. Di Rosa1, S. Guatelli2, M.G. Pia2, G. Russo1
1INFN Laboratori Nazionali del Sud, Italy
2INFN Genova, Italy

2. Contents User requirements Design of the physics component
Implementation
Geometry component
Primary particle component
Physics component
Calculation of the energy deposit
Analysis component
How to execute the Hadrontherapy advanced example

3. User requirements

4. Results of the simulation
User requirements
The user shall be able to:
Model a hadrontherapy beam line in terms of
Geometry components
Proton beam
Model a phantom as a water box
Model the electromagnetic and hadronic interactions
Choose alternative approaches interactively to model
Electromagnetic interactions
Hadronic interactions
Calculate the energy deposit in the phantom derived from:
Both primary (the incident proton beam) and secondary particles
Store the results of the simulation
3D energy deposit in the phantom
Bragg peak
Etc.
in histograms and n-tuples
Visualise the experimental set-up and the tracks of the particles
Experimental set-up
Physics
Results of the simulation
Visualisation

5. Design of the physics component
Particles
Messenger
Alternative approaches to model p, n, pions hadronic interactions
Modularised physics component
The user can configure the simulation with different physics options transparently
Alternative approaches to model
protons, ions, e-, photons, e+ EM interactions

6. Implementation

7. Implementation Hadrontherapy example Classes
header files in include/*.hh, source code in src/ *.cc
main in Hadrontherapy.cc
macro: defaultMacro.mac
Classes
HadrontherapyAnalysisManager
HadrontherapyDetectorConstruction
HadrontherapyDetectorMessenger
HadrontherapyMaterial
HadrontherapyPrimaryGeneratorAction
HadrontherapyPhysicsList
HadrontherapyPhysicsListMessenger ……

8. Detector Component
The proton beam line is modelled in the experimental set-up in terms of:
Geometrical components
Materials
Geant4 simulation

9. Primary particle component
Mean value
Sigma
Energy
63.5 MeV
400. keV
Position
(x0, 0, 0)
(0., 1., 1.) mm
Direction
(1., 0., 0.)
(0., , )
The primary particles are protons
Origin of the primary particles
X axis

10. Physics component Hadronic Electromagnetic
Parameterized (à la GHEISHA)
Nuclear Deexcitation
Default evaporation
GEM evaporation
Fermi break-up
Pre-equilibrium
Precompound model
Bertini model
Intra-nuclear cascade
Bertini cascade
Binary cascade
Elastic scattering
Parameterized
Bertini
For protons and ions
Standard
Low Energy – ICRU 49
Low Energy – Ziegler 1977
Low Energy – Ziegler 1985
Low Energy – Ziegler 2000
For electrons and photons
Low Energy – Livermore
Low Energy – Penelope
For positrons
Low Energy - Penelope

11. Phantom The phantom is set in front the beam line
Phantom: water box ( size: 40 mm )
Water box
X axis
The phantom is subdivided in 200 voxels along x, y, z axis
The energy deposit is calculated in the voxels
The result of the simulation is:
3D energy deposit in the phantom
Energy deposit with respect to the depth in the phantom along the x axis

12. Analysis component AIDA 3.2.1 and PI 1.3.8
The simulation produces a .hbk file at the end
hadrontherapy.hbk
The Bragg peak is saved in a 1D histogram (ID = 10)
The 3D energy deposit in the phantom is stored in a ntuple
3 109 events

13. Control, monitor the simulation

14. Messengers Interactive commands are defined to select: to change:
Physics processes
Physics models
To model electromagnetic and hadronic interactions of particles
to change:
Geometrical parameters of the proton beam line
Energy, position and direction of the primary particles

15. How to select the physics models
Example of macro:
/control/verbose 1
……..
/physics/addPhysics photon-epdl
/physics/addPhysics electron-eedl
/physics/addPhysics positron-standard
/physics/addPhysics ion-LowE
/physics/addPhysics muon-standard
/physics/addPhysics decay
/physics/addPhysics proton-precompound
/run/initialize
/run/beamOn 100

16. How to run Define necessary environment variables
source …
How to compile and link
gmake
How to run
$G4WORKDIR/bin/Linux/Hadrontherapy
(defaultmacro.mac is executed by default)
Result of the simulation: hadrontherapy.hbk

17. Comments on the Geant4 physics
Wide set of physics processes and models offered by Geant4
The Hadrontherapy advanced example provides examples of physics lists
How to best choose the most appropriate model for a particular experimental set-up?
The user has to select the physics models
Electromagnetic and hadronic components
The user has to validate his/her Geant4 physics component with respect to reference data
A comprehensive assessment of Geant4 electromagnetic physics with respect to established reference data is documented in:
K. Amako et al.,
Comparison of Geant4 electromagnetic physics models against the NIST reference data IEEE Trans. Nucl. Sci., Vol. 52, Issue 4, Aug. 2005, pp