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0001
0002 =========================================================
0003 Geant4 - Brachytherapy example
0004 =========================================================
0005
0006 README
0007 ---------------------
0008
0009
0010 The brachytherapy example is currently maintained and upgraded by Susanna Guatelli (1), Albert Le (1) and Dean Cutajar (1), with the support of
0011 Luciano Pandola (2)
0012
0013 1. Centre For Medical Radiation Physics (CMRP), University of Wollongong, NSW, Australia.
0014 2. LNS, INFN, Catania, Italy.
0015
0016 ------------------------------------------------------------------------
0017
0018 Contact: susanna@uow.edu.au
0019 deanc@uow.edu.au
0020 geant4-advanced-examples@cern.ch
0021
0022 ------------------------------------------------------------------------
0023
0024 List of past co-authors:
0025 S. George, S. Agostinelli, F. Foppiano, S. Garelli, M. G. Pia, M. Tropeano
0026
0027 -----------------------------------------------------------------
0028 ----> Introduction.
0029
0030 Brachytherapy example simulates the energy deposit in a water phantom, produced by:
0031 1) Iridium sources (Flexisource and TG186).
0032 2) Iodine sources (Bebig Isoseed and Oncura 6711 I-125).
0033 3) Leipzig Applicator with an iridium source (model from the Istituto Tumori, Genova, Italy).
0034
0035 The Flexisource, an Ir-192 source manufactured by Nucletron, an Elekta company, is a source commonly used for high dose rate brachytherapy treatments.
0036 The geometry of the Flexisource was adapted from D. Granero, J. Pérez-Calatayud, E. Casal, et al,
0037 "A dosimetric study on the Ir-192 high dose rate Flexisource", Med. Phys. 33 (12), 2006, 4578-82.
0038
0039 The TG186 source is a generic Ir-192 source created to provide developers of model based dose engines with a method of validating new dose calculation techniques.
0040 Details of the TG186 source may be obtained from Facundo Ballester, Åsa Carlsson Tedgren, Domingo Granero, et al,
0041 "A generic high-dose rate 192Ir brachytherapy source for evaluation of model-based dose calculations beyond the TG-43 formalism", Med. Phys. 42, 2015, 3048-62
0042
0043 In particular in this example it is shown how to:
0044 - model a radioactive source in terms of radiation field and geometry
0045 - model the radiation field with the General Particle Source with two alternative methods:
0046 1) Define the energy spectrum of photons exiting the radioactive core
0047 2) Modelling the Radioactive decay
0048 - calculate the energy deposition in a phantom by means of the G4 scoring mesh
0049 - define the physics by means of a Geant4 Modular Physics List
0050 - save results in an analysis ROOT file
0051 - calculate the dose rate distribution along the main axis of the source
0052 - compare the calculated dose rate distribution to reference data.
0053
0054 In the case of the example, the dose rate distribution of a Flexisource is compared to D. Granero,
0055 J. Pérez-Calatayud, E. Casal, et al,"A dosimetric study on the Ir-192 high dose rate Flexisource", Med. Phys. 33 (12), 2006, 4578-82.
0056 The dose rate distribution of the Oncura 6711 I-125 source is compared to J. Dolan, Z. Lia, J. F. Williamson, "Monte Carlo and experimental
0057 dosimetry of an I-125 brachytherapy seed", Med. Phys. 33(12), 2006.
0058
0059 The example can be executed in multithreading mode.
0060
0061 ------------------------------------------------------------------------
0062 ----> 1.Experimental set-up.
0063
0064 The default source is a Ir-192 Flexisource set in the center of a water phantom with size 30 cm.
0065 The phantom is set in the World volume filled with air.
0066
0067 The primary radiation field is defined by means of the GeneralParticleSource
0068 -------------------------------------------------------------------------
0069 ----> 2.SET-UP
0070
0071 A standard Geant4 example CMakeLists.txt is provided.
0072
0073 ------------------------------------------------------------------------
0074 ----> 3.How to run the example.
0075
0076 - Batch mode:
0077 $G4WORKDIR/bin/Linux-g++/Brachy FlexiSourceMacro.mac
0078 $G4WORKDIR/bin/Linux-g++/Brachy LeipzigSourceMacro.mac
0079 $G4WORKDIR/bin/Linux-g++/Brachy IridiumSourceMacro.mac
0080 $G4WORKDIR/bin/Linux-g++/Brachy IodiumSourceMacro.mac (model of the Bebig Isoseed I-125)
0081 $G4WORKDIR/bin/Linux-g++/Brachy OncuraIodineSourceMacro.mac (model of the Oncura 6711 I-125)
0082 $G4WORKDIR/bin/Linux-g++/Brachy LeipzigSourceMacro.mac
0083
0084 - Interative mode:
0085 3) $G4WORKDIR/bin/Linux-g++/Brachy
0086 VisualisationMacro.mac is loaded automatically.
0087
0088 * How to change the absorber material of the phantom:
0089 idle>/phantom/selectMaterial materialName
0090
0091 ---------------------------------------------------------------------------------
0092 ----> 4. Primary radiation Field
0093
0094 The radiation field is defined with the General Particle Source.
0095
0096 Two alternative options are offered:
0097 1) Define gamma as primary radiation field. The gamma are originated from the radioactive core.
0098 This radiation field is defined in:
0099 iodine_source_primary.mac and iridium_source_primary.mac
0100
0101 2) Model the radioactive Decay. The primary particle is the radionuclide.
0102 This option is modelled in iodine_decay.mac and TG186_iridium_decay.mac
0103
0104 The GPS macros are executed in VisualisationMacro.mac by default, FlexiSourceMacro.mac, IodineSourceMacro.mac, LeipzigSourceMacro.mac
0105
0106 - The Flexisource is the default source of the example.
0107 - In VisualisationMacro.mac the source is the default one. iridium_source_primary.mac is executed to define the radiation field emerging from the iridium core.
0108 - In FlexiSourceMacro.mac the Flexi Ir source geometry is selected via interactive command. The radiation field is defined in the iridium_source_primary.mac.
0109 - In IodineSourceMacro.mac, the Bebig Isoseed I-125 brachytherapy source is modelled. The radiation field is modelled in terms of emitted photons in iodine_source_primary.mac.
0110 Alternatively the radioactive decay of I can be modelled using teh macro iodine_decay.mac.
0111 - In LeipzigSourceMacro.mac, A Leipzig applicator (design provided by Istituto Tumori, Genova) is modelled. The iridium_source_leipzig_primary.mac defines the radiation field of the Ir core.
0112 - The TG186SourceMacro.mac models the reference bIr brachytherapy source. The radiation field can be either defined with the iridium_source_primary.mac (spectrum of the emitted photons) or with TG186_iridium_decay.mac (model of the Ir decay).
0113 - OncuraIodineSourceMacro.mac models both the geometry and the radioactive decay of the Oncura 6711 I-125 source.
0114 --------------------------------------------------------------------------------
0115 ----> 5. Physics List
0116
0117 The electromagnetic Livermore Low Energy physics is active as well as the radioactive decay.
0118 The cut is 0.05 mm.
0119 Fluorescence and Auger electron emission are included.
0120
0121 ------------------------------------------------------------------------
0122 ----> 6. Scoring mesh
0123
0124 The scoring mesh is used to calculate the energy deposition in the plane containing the source (z=0 plane)
0125 integrated over the whole run. The scoring mesh is defined in the input macro files.
0126 The default output format of the scoring is changed in the class BrachyUserScoreWriter.
0127 The scoring mesh is fixed with a size of 20.025 cm along x and y. The bin size is 0.25 mm along x, y and z.
0128
0129 When running in interactive mode there is no scoring mesh.The user has to add it with appropriate UI
0130
0131 ------------------------------------------------------------------------
0132 ----> 6. Analysis
0133
0134 G4Analysis is used to create and fill histograms in ROOT output files.
0135
0136 The installation of ROOT is required to plot the results of the simulation contained
0137 in primary.root and brachytherapy.root(http://root.cern.ch/drupal/).
0138
0139 ------------------------------------------------------------------------
0140 ----> 7. Simulation output
0141
0142 The output is:
0143
0144 - ASCII file EnergyDeposition.out, with xx (mm), yy(mm), zz(mm), and energy deposition (keV), in the phantom.
0145 To limit the use of memory, the energy deposition is scored only in the plane containing the source, however this can be changed by the user.
0146
0147 By default:
0148 EnergyDeposition_Flexi.out contains the Edep when the Flexi source is selected.
0149 EnergyDeposition_iodine.out contains the Edep when Iodine Bebig Isoseed source is selected.
0150 EnergyDeposition_TG186.out contains the Edep when the TG186 source is selected.
0151 EnergyDeposition_Leipzig.out contains the Edep when the Iridium source with Leipzig applicator is selected.
0152 EnergyDeposition_Oncura.out contains the Edep when the Iodine Oncura 6711 source is selected.
0153
0154 - brachytherapy.root, containing a 2D histogram with the energy deposition in the phantom. The macro macro.C is provided as example
0155 to open brachytherapy.root in ROOT interactive session and to plot the results of the simulation.
0156
0157 - primary.root, with 1D histogram of the energy spectrum of photons emitted by the radionuclide (see section 4).
0158 plot_primary.C is provided as example to open primary.root and to plot the energy spectra
0159
0160 -------------------------------------------------------------------------------
0161 ----> 8.Visualisation
0162
0163 A macro is provided ad example of visualisation: VisualisationMacro.mac.
0164
0165 -------------------------------------------------------------------------------
0166 -----> 9. Comparison to reference data
0167
0168 The ROOT macros macro.C and plot_primary.C are provided to plot the results of the simulation, contained
0169 in the brachytherapy.root file.
0170
0171 The ROOT macro TG43_relative_dose.C has brachytherapy.root as input file. It calculates the dose rate distribution along the main axis of
0172 the brachytherapy source. The dose rate is normalised to 1 at 1 cm distance from the centre.
0173 The output file is geant4_dose.txt with two columns:
0174 distance from the centre (cm) dose rate distribution
0175
0176 The user can then compare the dose rate distribution calculated with the example to reference data.
0177
0178 Directory "comparison":
0179 As an example, the dose rate distribution calculated with the Flexisource is compared to reference data from D. Granero, J. Pérez-Calatayud, E. Casal, et al, "A dosimetric study on the Ir-192 high dose rate Flexisource", Med. Phys. 33 (12), 2006, 4578-82.
0180
0181 The compare.C is a ROOT macro which reads the dose rate distribution calculated with the Flexisource (geant4.txt generated with the advanced example and 280 M histories ) against the reference.
0182
0183 The directory "comparison" contains:
0184 - the reference data, granero.txt
0185 - the data obtained in Geant4.10.3: geant4.txt, 280 M events. geant4.txt is obtained when executing the macro TG43_relative_dose.C
0186 - comparison.C - macro to read geant4.txt and granero.txt and compare them in the same plot
0187
0188 -----> 10. Regression testing of Geant4
0189 - the macros to run are in test_macro
0190 - the results should be processed with analysis.C
0191
0192
