Gabriele Cosmo
230 lines
8.5 KiB
Plaintext
230 lines
8.5 KiB
Plaintext
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=========================================================
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Geant4 - Hadrontherapy example
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=========================================================
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README file
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----------------------
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AUTHORS
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G.A.P. CIRRONE(a *), G.CUTTONE(a), F. DI ROSA(a), G.RUSSO(a)
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a. Laboratori Nazionali del Sud - Istituto Nazionale di Fisica Nucleare
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95123 Catania, Italy
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* e-mail:cirrone@lns.infn.it
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M.G. PIA(b)
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b. Istituto Nazionale di Fisica Nucleare, Sezione di Genova Via Dodecaneso, 33
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16146, Genova, Italy
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A. LECHNER (c)
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c. CERN, Switzerland
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More informations on the Hadrontherapy example can be found in the
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Hadrontherapy Documentation available at http://www.ge.infn.it/geant4/examples/
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Alternatevely send an e-mail to cirrone@lns.infn.it.
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---->0. INTRODUCTION.
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The hadrontherapy example simulates a hadron therapy beam line.
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In particular the example models the specific proton therapy beam line
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installed at Laboratori Nazionali del Sud (INFN) in Catania, Sicily (Italy).
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For more information on the proton therapy center of Catania
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or/and proton/hadron therapy in general, please visit the
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pages:
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http://www.lns.infn.it/catanaweb/catana/
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---->1. GEOMETRY SET-UP.
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The elements simulated are:
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1. A scattering system, to spread geometrically the beam;
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2. A system of collimators, to avoid the scattering radiation;
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3. A modulation system that spreads the beam in energy and
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produces the so-called spread out bragg peak;
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It is constituted by a rotating wheel of different thichnesses.
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The wheel rotates around is axis (parallel to the proton
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beam axis) and its movement can be obtained by means of a
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messenger between runs.
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4. A set of monitor chambers (special transmission ionisation
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chambers used to control hadron flux during the irradiation);
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5. A "nozzle" and a final collimator defining the final shape
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of the beam before reaching the patient.
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6. A water phantom: it is a box of water where the energy deposit is
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calculated.
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The use of the water phantom is required by the international protocol
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on the measure of dose in the case of proton and ion beams (IAEA 398, 2000).
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---->2. EXPERIMENTAL SET-UP.
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The application simulates the proton therapy beam line
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installed at Laboratori Nazionali del Sud.
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The default beam line is a typical treatment line composed by several elements all
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devoted to create the so-called "terapeutical beam", i.e. a beam ideal
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for a radiotherapeutic treatment.
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The main elements are:
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** The COLLIMATORS: placed along the beam line to collimate the beam;
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** The RANGE SHIFTERS: to decrease the energy of the primary proton beam
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to a specific value;
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** The MODULATOR WHEEL: to modulate the energy of the primary and monoenergetic
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beam in to a wide spectrum. The energy modulation is necessary to
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homogeneusly irradiate a tumour volume that can extends in depth
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up to 20 mm;
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** The MONITOR CHAMBERS: very thin ionisation chamber that permit the
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dose monitoring during the patient irradiation;
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** The PATIENT COLLIMATOR: a brass, tumour-shaped collimator able to
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confine the proton irradiation field in order to irradiate just the tumour mass
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in the trasverse direction;
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The user has the possibility to vary, via messenger, almost all the geometrical
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characteristics of the beam line elements (i.e. their position along the beam line,
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their thickness, etc.). More details on the available user messengers can be
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found in the Hadronterapy Documentation (http://www.ge.infn.it/geant4/examples/).
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At the end of the beam line, a typical water phantom is reproduced.
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A user-defined region of the phantom is divided (via the ROGeomtry class) in
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cubic and identical voxels. The voxels size can be varied. At the end of the simulation
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the energy deposited by primary protons, and secondaries in each voxel
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is collected. This information is available as an .hbk file (if the
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G4ANALYSIS_USE variable is defined).
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The default sizes of the active voxelized region are 40x40x40 mm corresponding
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to a matric of 80x80x80 cubic voxels each with a lateral dimension of 0.5 mm.
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---->3. SET-UP
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- a standard Geant4 example GNUmakefile is provided
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setup with:
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compiler = gcc-3.2.3
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G4SYSTEM = linux-g++
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The following section reports the necessary environment variables
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necessary for the run of Hadrontherapy.
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---->3.1 ENVIROMENT VARIABLES
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- G4SYSTEM = Linux-g++
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- G4INSTALL points to the installation directory of GEANT4;
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- G4LIB point to the compiled libraries of GEANT4;
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- G4WORKDIR points to the work directory;
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- CLHEP_BASE_DIR points to the installation directory of CHLEP;
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- G4LEVELGAMMADATA points to the photoevaporation library;
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- NeutronHPCrossSections points to the neutron data files;
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- G4RADIOACTIVEDATA points to the libraries for radio-active decay
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hadronic processes;
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- G4LEDATA points to the low energy electromagnetic libraries
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- LD_LIBRARY_PATH = $CLHEP_BASE_DIR/lib
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---->3.2 VISUALISATION
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The user can visualise the experimental set-up with OpenGL, DAWN and vrml
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---->4. HOW TO RUN THE EXAMPLE
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In interactive mode:
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> $G4WORDIR/bin/Linux-g++/Hadrontherapy
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The defaultMacro.mac is executed
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The primary particle beam parameter are:
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Radiation: proton beam;
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Energy distribution: gaussian;
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Mean energy: 63.4 MeV;
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Energy spread: 300 keV;
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Beam spot size: 1 mm;
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Beam angular spread: 0.057 deg;
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The modulator wheel can be rotated via the messenger:
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Idle>/modulator/angle/xx deg
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To produce a Spread Out Bragg Peak using the modulator a macro
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(modulatorMacro.mac) is provided. With this macro the modulator is
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rotated of 360 degree at 1 deg steps. In each run 1000 protons are
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generated as primary particles. Obviously a bigger resolution can be obtained
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with smaller angles or increasing the protons number in each run.
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Modulator wheel can be omitted setting its material air.
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run $G4WORKDIR/bin/Linux-g++/Hadrontherapy visualisationMacro.mac
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to visualise the experimental set-up with OpenGL
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---->5. PHYSICS
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Both electromagnetic and hadronic physic processes are activated for
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the particles of the experimental set-up.
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Different physics models can be activated by the user interactively.
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Examples of activation are provided in the macro files starting
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with the string "physics":
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All possible physics options are summarized in the file
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physicsAllOptions.mac.
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Different options concerning electromagnetic interactions of protons
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and neutrons can be tested with the files:
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physicsElectromagneticICRU49.mac
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physicsElectromagneticZiegler77.mac
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physicsElectromagneticZiegler85.mac
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Different options concerning hadronic interactions of protons and
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neutrons can be tested with the files:
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physicsHadronicBertini.mac
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physicsHadronicBinary.mac
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physicsHadronicLEP.mac
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physicsHadronicPrecompound.mac
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NOTE: Apart from the different models for protons and neutrons, a user
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can also select among several interaction models for particles like
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electrons or photons. All possible options are listed in the file
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physicsAllOptions.mac.
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---->6. SIMULATION OUTPUT
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The output is an .hbk file (hadrontherapy.hbk) produced
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if the variable G4ANALYSIS_USE is set to 1 and the analysis tool (AIDA
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interface) correctly installed.
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The file contains an histogram and an n-tuple.
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The histogram contains the Bragg curve: energy deposited
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by the proton beam (in MeV) versus the depth in water (in mm).
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The n-tuple contains the total 3D energy deposit in the phantom; the information
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is energy deposit in each voxel with respect to the position of the voxel.
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Setup for analysis: AIDA 3.2.1
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Users can download the analysis tools from:
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http://aida.freehep.org/
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Note that the same information can be stored in any different format.
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Please contact cirrone@lns.infn.it if you want store the information in
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a different format.
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---------------------------------------------------------------------------
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for comments, advices, doubts and questions please contact:
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cirrone@lns.infn.it, giorgiorusso@lns.infn.it
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last modified: A. Lechner, 16/11/2007
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