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, 13-20 July 2005 Susanna Guatelli

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

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

The Hadrontherapy advanced example Documentation of the example: www.ge.infn.it/geant4/examples/index.html Code review of the example in occasion of the last Geant4 public release (7.1) Other changes: functionality added Susanna Guatelli

Design Primary particle Detector Physics List Analysis Susanna Guatelli

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

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 = -3428.59 mm, y = 0., y = 0.) Sigma position (0., 1. mm, 1. mm) Mean direction (1., 0., 0.) Sigma position (0., 0.0001, 0.0001) Mean energy 63.45 MeV Sigma energy 400 keV Susanna Guatelli

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

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

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

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

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

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

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

Parameters Threshold of production of secondary particles: 10 * mm Cut per region fixed in the sensitive detector: 0.001 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

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

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

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

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

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