The Hadrontherapy Geant4 advanced example by X0Nn69I

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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 Validation
                     INF Genova, 13-20 July 2005


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

•   Dosimetry study




     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




Susanna Guatelli   Analysis
               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     Proton
type
                                                                   • The primary particle
Position
              Mean position    (x = -3428.59 mm, y = 0., y = 0.)   component is provided
              Sigma position   (0., 1. mm, 1. mm)                  of a messenger
Direction     Mean direction   (1., 0., 0.)
                                                                   • It is possible to
              Sigma position   (0., 0.0001, 0.0001)
                                                                   change these
Energy        Mean energy      63.45 MeV                           parameters interactively
              Sigma energy     400 keV

      Susanna Guatelli
 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,
   – Standard

• 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+:
       – LowEnergy Penelope,
       – Standard

 • The user can choose to activate for gamma:
       – LowEnergy EPDL,
       – LowEnergy Penelope,
       – Standard
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
                               + default evaporation
                               + GEM evaporation
• Precompound model            + default evaporation + Fermi Break-up
                               + GEM evaporation + Fermi Break-up



• Binary model + Precompound model ( with all the option showed
  above )

• Bertini model

• LEP
     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
                             Proton beam
     –   He3
     –   Tritium
     –   Deuterium
along the x axis                                         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

								
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