The Hadrontherapy Geant4 advanced example

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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 ValidationINF Genova, 13-20 July
2005
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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

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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

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The Hadrontherapy advanced example

• Documentation of the example www.ge.infn.it/geant
  4/examples/index.html
• Code review of the example in occasion of the
  last Geant4 public release (7.1)
• Other changes functionality added

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Design
Primary particle
Detector
Physics List
Analysis
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Simulation components

• Primary particles
• Physics List
• Detector Construction
• Energy deposit
• Stepping action
• Analysis

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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
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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, a, ions, e-, e, pions,
neutrons, muons
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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, a, ions the
  alternative models
• Low Energy ICRU,
• Standard
• In the case of Low Energy Physics, also the
  nuclear stopping power is active

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EM Physics models

• The user can choose to activate for e-
• LowEnergy EEDL,
• LowEnergy Penelope,
• Standard
• The user can choose to activate for e
• LowEnergy Penelope,
• Standard
• The user can choose to activate for gamma
• LowEnergy EPDL,
• LowEnergy Penelope,
• Standard

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Hadronic physics

• Elastic scattering
• Inelastic scattering
• Alternative approaches for p, n, pions
• LEP ( E lt 100 MeV) and Binary Ion model ( E gt 80
  MeV) for d, t, a
• Neutron fission and capture

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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
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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

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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

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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

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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
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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

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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

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Future developments of the Geant4 hadrontherapy
advanced example

• Design iteration
• How to model more efficiently the geometry of the
  beam line
• Code review

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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