Gabriele Cosmo
212 lines
8.3 KiB
Plaintext
Executable File
212 lines
8.3 KiB
Plaintext
Executable File
|
|
=========================================================
|
|
Geant4 - Hadrontherapy example
|
|
=========================================================
|
|
|
|
README
|
|
---------------------
|
|
|
|
This example is developed by G.A.Pablo Cirrone, Giorgio Russo and
|
|
Francesco Di Rosa of the Laboratori Nazionali del Sud - Istituto Nazionale
|
|
di Fisica Nucleare, Via S. Sofia, 44 Catania, Sicily, Italy (www.lns.infn.it)
|
|
|
|
The authors are supported by Laboratori Nazionali del Sud, Catania and by the
|
|
Dipartimento di Fisica of Catania University, Catania.
|
|
|
|
The authors wish to thank Susanna Guatelli and Maria Grazia Pia for
|
|
their support in the realization of the sensitive detector and
|
|
Harald Paganetti (from NPTC, Massachussets (US)) for the
|
|
help in the realization of the movement of the modulator wheel.
|
|
------------------------------------------------------------------------
|
|
----> INTRODUCTION.
|
|
|
|
The hadrontherapy example simulates a hadron therapy beam line.
|
|
In particular the example models the specific proton therapy beam line
|
|
installed at Laboratori Nazionali del Sud (INFN) in Catania, Sicily (Italy).
|
|
For more information on the proton therapy center of Catania
|
|
or/and proton/hadron therapy in general, please visit the
|
|
pages:
|
|
> www.lns.infn.it/~catana
|
|
|
|
----> GEOMETRY SET-UP.
|
|
|
|
The elements simulated are:
|
|
|
|
1. A scattering system, to spread geometrically the beam;
|
|
|
|
2. A system of collimators, to avoid the scattering radiation;
|
|
|
|
3. A modulation system that spreads the beam in energy and
|
|
produces the so-called spread out bragg peak;
|
|
It is constituted by a rotating wheel of different thichnesses.
|
|
The wheel rotates around is axis (parallel to the proton
|
|
beam axis) and its movement can be obtained by means of a
|
|
messenger between runs.
|
|
|
|
4. A set of monitor chambers (special transmission ionisation
|
|
chambers used to control hadron flux during the irradiation);
|
|
|
|
5. A "nozzle" and a final collimator defining the final shape
|
|
of the beam before reaching the patient.
|
|
|
|
6. A water phantom: it is a box of water inside of which the
|
|
dosimeter is placed; the dosimeter performs the measurements of
|
|
dose distributions.
|
|
The use of the water phantom is required by the international protocol
|
|
on the measure of dose in the case of proton and ion beams (IAEA 398, 2000).
|
|
|
|
7. A "Markus" ionisation chamber, to reconstruct the depth dose distribution
|
|
(Bragg curve).
|
|
|
|
8. A radiographic film, to evaluate the beam lateral dose
|
|
distribution, registering the spatial distribution of the
|
|
primary particles
|
|
|
|
------------------------------------------------------------------------
|
|
----> 1.EXPERIMENTAL SET-UP.
|
|
|
|
The application fully simulates the proton therapy beam line
|
|
installed at Laboratori Nazionali del Sud. Inside the water
|
|
phantom (placed at the end of the proton beam line) the Markus ionisation
|
|
chamber and a radiographic film are located; these elements permit the
|
|
reconstruction of the Bragg curve (registered on the file BraggPeak.out)
|
|
and of the lateral and energy distribution of the particles (registered
|
|
on the files energyDistribution.out and angularDistribution.out). Please
|
|
see later for the description of the produced files.
|
|
The Markus chamber is realized by means of a water cylinder (placed inside
|
|
the water phantom) with its main axis coincident with proton beam axis.
|
|
The cylinder is divided in slices and the energy deposit in each slide is
|
|
collected at the end of each run. The default thickness of the slices
|
|
is 2 micron.
|
|
The radiographic film is simulated by a plane. It is located, by default,
|
|
at the entrance window of the water phantom (the isocenter point) and
|
|
its thickness is 1. mm.
|
|
|
|
-------------------------------------------------------------------------
|
|
----> 2.SET-UP
|
|
|
|
- a standard Geant4 example GNUmakefile is provided
|
|
|
|
setup with:
|
|
compiler = gcc-3.2.3
|
|
G4SYSTEM = linux-g++
|
|
|
|
The following section reports the necessary environment variables
|
|
necessary for the run of Hadrontherapy.
|
|
|
|
----> 2.1 ENVIROMENT VARIABLES
|
|
|
|
- G4SYSTEM = Linux-g++
|
|
|
|
- G4INSTALL points to the installation directory of GEANT4;
|
|
|
|
- G4LIB point to the compiled libraries of GEANT4;
|
|
|
|
- G4WORKDIR points to the work directory;
|
|
|
|
- CLHEP_BASE_DIR points to the installation directory of CHLEP;
|
|
|
|
- G4LEVELGAMMADATA points to the photoevaporation library;
|
|
|
|
- NeutronHPCrossSections points to the neutron data files;
|
|
|
|
- G4RADIOACTIVEDATA points to the libraries for radio-active decay
|
|
hadronic processes;
|
|
|
|
- G4LEDATA points to the low energy electromagnetic libraries
|
|
|
|
- LD_LIBRARY_PATH = $CLHEP_BASE_DIR/lib
|
|
|
|
----> 2.2 VISUALISATION
|
|
|
|
The user can visualise the experimental set-up with OpenGL, DAWN and vrml
|
|
|
|
------------------------------------------------------------------------
|
|
----> 3. HOW TO RUN THE EXAMPLE.
|
|
|
|
In interactive mode:
|
|
> $G4WORDIR/bin/Linux-g++/Hadrontherapy
|
|
The defaultMacro.mac is executed
|
|
|
|
The primary particle beam parameter are:
|
|
Radiation: proton beam;
|
|
Energy distribution: gaussian;
|
|
Mean energy: 63.4 MeV;
|
|
Energy spread: 300 keV;
|
|
Beam spot size: 1 mm;
|
|
Beam angular spread: 0.057 deg;
|
|
|
|
|
|
Cut per region feature permits to set different cut in different regions.
|
|
In this example it is sufficient to set a small cut inside the dosemeter
|
|
(where the information of dose distribution is collected).
|
|
|
|
Default values are:
|
|
cut = 10 mm along the beam line;
|
|
cut = 0.2 mm inside the dosemeter;
|
|
|
|
The modulator wheel can be rotated via the messenger:
|
|
|
|
Idle>/modulator/angle/modAngle xx deg
|
|
|
|
It is sufficient to rotate the modulator from 0 deg (default position)
|
|
to 45 deg using 1 deg steps to obtain a Spread Out Bragg Peak (SOBP).
|
|
|
|
Modulator wheel can be omitted setting its material air.
|
|
|
|
run $G4WORKDIR/bin/Linux-g++/Hadrontherapy visualisation.mac
|
|
to visualise the experimental set-up with OpenGL
|
|
-----------------------------------------------------------------------
|
|
----> 4. PHYSICS
|
|
|
|
Electromagnetic and hadronic processes are modeled.
|
|
|
|
The LowEnergy package is used to model the electromagnetic processes
|
|
of all the particles involved in the experimental set-up.
|
|
|
|
------------------------------------------------------------------------
|
|
----> 5. SIMULATION OUTPUT
|
|
|
|
The output is in ASCII file format:
|
|
|
|
1.) BraggPeak.out: a two columns file.
|
|
The first column represent depth in water (mm), the second contains the energy
|
|
deposit (MeV).
|
|
|
|
2.) energyDistribution.out: a two columns file.
|
|
The first column contains the energy deposit (in MeV) by primary particles
|
|
in the plane (radiographic film) positioned at isocenter.
|
|
The second column indicates the number of the primary particle
|
|
responsible for the energy deposit.
|
|
|
|
3.) angularDistribution.out: a three columns file.
|
|
It contains the coordinates in millimeters (x, y, z) of a primary
|
|
particle interacting with the plane representing the radiographic film.
|
|
x direction is along the beam direction,
|
|
y and z directions are orthogonal to the beam direction.
|
|
|
|
------------------------------------------------------------------------
|
|
----> 6. FUTURE PLANS
|
|
|
|
Next planned improvements will be:
|
|
|
|
** Use of AIDA and PI analysis tools to store the results of the
|
|
simulation in .xml/.hbk files
|
|
|
|
** Addition of messengers to interactively change position, dimension
|
|
and composition of all the beam line elements and of the
|
|
simulated dosimetric systems and to change cut values;
|
|
|
|
** Addition of messenger to change energy, energy spread,
|
|
beam spot size and angular divergence of the proton beam;
|
|
|
|
** Realization of the read-out-geometry: this will permit to collect
|
|
the energy deposit inside a voxelized three dimensional volume.
|
|
--------------------------------------------------------------------------
|
|
|
|
for comments, advices, doubts and questions please contact:
|
|
cirrone@lns.infn.it, giorgiorusso@lns.infn.it
|
|
|
|
last modified: Susanna Guatelli, 28/5/2004
|
|
|