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| == Simulation of the Clatterbridge beamline ==
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| This simulation models the monoenergetic 62.5 MeV proton beam at Clatterbridge Cancer Centre, as it traverses the components of the beamline and is then deposited into a volume of water. The beamline components are contained within a geometry modelling the Clatterbridge treatment room. | | This simulation is a model of the monoenergetic 62.5 MeV proton beam at the [http://www.clatterbridgecc.nhs.uk/patients/treatment-and-support/proton-therapy Clatterbridge Cancer Centre] as it traverses the components of the beamline and finally hits a volume of water. |
| | | The simulation was built using: |
| The protons are generated using the G4ParticleGun class, and the physics list used is QGSP_BIC_HP, standard for simulating clinical proton beams. | | * [[/Geant4 | Geant4]] |
| | | ** The simulation was built on the example in <code>examples/extended/electromagnetic/TestEm7</code> supplied with the Geant4 package and detailed [http://www.hep.ucl.ac.uk/pbt/wiki/Software/Geant4/Tutorials/Basic/Monoenergetic_Proton_Pencil_Beam here]. |
| The energy of the beam after travelling through the beamline components is measured by tracking the energy deposition of individual protons within the water volume, using the G4Track class. This simulation produces a post-beamline energy of 60.08 MeV and a Bragg peak at depth [insert depth].
| | * [[/TOPAS | TOPAS]] |
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| [[File:vis.pdf]] | |
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| == Running the simulation ==
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| '''Run macro proton.mac'''
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| <pre>
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| [username@plus1 ProtonPB_build]$ ./protonPB proton.mac
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| </pre>
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| '''Open ROOT and run analysis file'''
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| <pre>
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| [username@plus1 ProtonPB_build]$ root -l
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| root [0] .x simulation_analysis.C
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| </pre>
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| == Data Analysis ==
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| The simulation code and <code> proton.mac </code> produce several output files: | |
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| === <code> kin.txt </code> ===
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| This text file contains the output information from <code> SteppingAction.cc </code>, printed on a step-by-step basis for each proton (event). The first column contains the <code> z </code> position of the particle, relative to the position of the source at the inner room boundary. The second column contains the energy (MeV) of the proton at this <code> z </code> position.
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| <pre>
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| 300 62.3248
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| 300 62.0776
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| 300 62.2042
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| 300 62.4347
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| 300 62.2698
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| 300 62.2164
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| </pre>
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| '''Open ROOT and run the simulation analysis file '''
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| <pre>
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| [username@plus1 ProtonPB_build]$ root -l
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| root [1] .x simulation_analysis.C
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| </pre>
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| == Changing parameters ==
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| === Scoring mesh ===
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| '''Longitudinal scoring mesh'''
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| A longitudinal scoring mesh extends along the length of the beamline from the source to the water volume. The mesh utilises a filter to detect the flux of protons per cm<sup>2</sup> and writes the data to the text file <code> FluxLongitudinal.txt </code>. The location of the mesh centre can be changed in <code> proton.mac </code>, in addition to the dimensions of the mesh and the number of bins.
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| '''Lateral scoring mesh'''
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| A lateral scoring mesh is positioned at the end of the nozzle to record the dose distribution of the protons.
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| === Initial beam parameters ===
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| Initial parameters of the proton beam can be modified in <code> proton.mac </code>
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| '''Beam radius'''
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| <pre>
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| /gps/pos/radius 3 mm | |
| </pre>
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| '''Beam energy'''
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| This simulation models the proton beam source with a Gaussian distribution.
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| <pre>
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| /gps/ene/type Gauss
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| /gps/ene/mono 62.5 MeV
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| /gps/ene/sigma 0.082 MeV
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| </pre>
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| '''Source position'''
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| The proton source is positioned at <code> z = -420 cm </code> relative to the centre of the inner room (the mother volume), which translates as the wall surface of the inner room.
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| <pre>
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| /gps/pos/type Plane
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| /gps/pos/shape Circle | |
| /gps/pos/centre 0.0 0.0 -420 cm | |
| </pre>
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| == Files ==
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