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1 2 ========================================================= 3 Geant4 - Brachytherapy example 4 ========================================================= 5 6 README 7 --------------------- 8 9 10 The brachytherapy example is currently maintained and upgraded by Susanna Guatelli (1), Albert Le (1) and Dean Cutajar (1), with the support of 11 Luciano Pandola (2) 12 13 1. Centre For Medical Radiation Physics (CMRP), University of Wollongong, NSW, Australia. 14 2. LNS, INFN, Catania, Italy. 15 16 ------------------------------------------------------------------------ 17 18 Contact: susanna@uow.edu.au 19 deanc@uow.edu.au 20 geant4-advanced-examples@cern.ch 21 22 ------------------------------------------------------------------------ 23 24 List of past co-authors: 25 S. George, S. Agostinelli, F. Foppiano, S. Garelli, M. G. Pia, M. Tropeano 26 27 ----------------------------------------------------------------- 28 ----> Introduction. 29 30 Brachytherapy example simulates the energy deposit in a water phantom, produced by: 31 1) Iridium sources (Flexisource and TG186). 32 2) Iodine sources (Bebig Isoseed and Oncura 6711 I-125). 33 3) Leipzig Applicator with an iridium source (model from the Istituto Tumori, Genova, Italy). 34 35 The Flexisource, an Ir-192 source manufactured by Nucletron, an Elekta company, is a source commonly used for high dose rate brachytherapy treatments. 36 The geometry of the Flexisource was adapted from D. Granero, J. Pérez-Calatayud, E. Casal, et al, 37 "A dosimetric study on the Ir-192 high dose rate Flexisource", Med. Phys. 33 (12), 2006, 4578-82. 38 39 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. 40 Details of the TG186 source may be obtained from Facundo Ballester, Åsa Carlsson Tedgren, Domingo Granero, et al, 41 "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 42 43 In particular in this example it is shown how to: 44 - model a radioactive source in terms of radiation field and geometry 45 - model the radiation field with the General Particle Source with two alternative methods: 46 1) Define the energy spectrum of photons exiting the radioactive core 47 2) Modelling the Radioactive decay 48 - calculate the energy deposition in a phantom by means of the G4 scoring mesh 49 - define the physics by means of a Geant4 Modular Physics List 50 - save results in an analysis ROOT file 51 - calculate the dose rate distribution along the main axis of the source 52 - compare the calculated dose rate distribution to reference data. 53 54 In the case of the example, the dose rate distribution of a Flexisource is compared to D. Granero, 55 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. 56 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 57 dosimetry of an I-125 brachytherapy seed", Med. Phys. 33(12), 2006. 58 59 The example can be executed in multithreading mode. 60 61 ------------------------------------------------------------------------ 62 ----> 1.Experimental set-up. 63 64 The default source is a Ir-192 Flexisource set in the center of a water phantom with size 30 cm. 65 The phantom is set in the World volume filled with air. 66 67 The primary radiation field is defined by means of the GeneralParticleSource 68 ------------------------------------------------------------------------- 69 ----> 2.SET-UP 70 71 A standard Geant4 example CMakeLists.txt is provided. 72 73 ------------------------------------------------------------------------ 74 ----> 3.How to run the example. 75 76 - Batch mode: 77 $G4WORKDIR/bin/Linux-g++/Brachy FlexiSourceMacro.mac 78 $G4WORKDIR/bin/Linux-g++/Brachy LeipzigSourceMacro.mac 79 $G4WORKDIR/bin/Linux-g++/Brachy IridiumSourceMacro.mac 80 $G4WORKDIR/bin/Linux-g++/Brachy IodiumSourceMacro.mac (model of the Bebig Isoseed I-125) 81 $G4WORKDIR/bin/Linux-g++/Brachy OncuraIodineSourceMacro.mac (model of the Oncura 6711 I-125) 82 $G4WORKDIR/bin/Linux-g++/Brachy LeipzigSourceMacro.mac 83 84 - Interative mode: 85 3) $G4WORKDIR/bin/Linux-g++/Brachy 86 VisualisationMacro.mac is loaded automatically. 87 88 * How to change the absorber material of the phantom: 89 idle>/phantom/selectMaterial materialName 90 91 --------------------------------------------------------------------------------- 92 ----> 4. Primary radiation Field 93 94 The radiation field is defined with the General Particle Source. 95 96 Two alternative options are offered: 97 1) Define gamma as primary radiation field. The gamma are originated from the radioactive core. 98 This radiation field is defined in: 99 iodine_source_primary.mac and iridium_source_primary.mac 100 101 2) Model the radioactive Decay. The primary particle is the radionuclide. 102 This option is modelled in iodine_decay.mac and TG186_iridium_decay.mac 103 104 The GPS macros are executed in VisualisationMacro.mac by default, FlexiSourceMacro.mac, IodineSourceMacro.mac, LeipzigSourceMacro.mac 105 106 - The Flexisource is the default source of the example. 107 - 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. 108 - In FlexiSourceMacro.mac the Flexi Ir source geometry is selected via interactive command. The radiation field is defined in the iridium_source_primary.mac. 109 - 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. 110 Alternatively the radioactive decay of I can be modelled using teh macro iodine_decay.mac. 111 - 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. 112 - 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). 113 - OncuraIodineSourceMacro.mac models both the geometry and the radioactive decay of the Oncura 6711 I-125 source. 114 -------------------------------------------------------------------------------- 115 ----> 5. Physics List 116 117 The electromagnetic Livermore Low Energy physics is active as well as the radioactive decay. 118 The cut is 0.05 mm. 119 Fluorescence and Auger electron emission are included. 120 121 ------------------------------------------------------------------------ 122 ----> 6. Scoring mesh 123 124 The scoring mesh is used to calculate the energy deposition in the plane containing the source (z=0 plane) 125 integrated over the whole run. The scoring mesh is defined in the input macro files. 126 The default output format of the scoring is changed in the class BrachyUserScoreWriter. 127 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. 128 129 When running in interactive mode there is no scoring mesh.The user has to add it with appropriate UI 130 131 ------------------------------------------------------------------------ 132 ----> 6. Analysis 133 134 G4Analysis is used to create and fill histograms in ROOT output files. 135 136 The installation of ROOT is required to plot the results of the simulation contained 137 in primary.root and brachytherapy.root(http://root.cern.ch/drupal/). 138 139 ------------------------------------------------------------------------ 140 ----> 7. Simulation output 141 142 The output is: 143 144 - ASCII file EnergyDeposition.out, with xx (mm), yy(mm), zz(mm), and energy deposition (keV), in the phantom. 145 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. 146 147 By default: 148 EnergyDeposition_Flexi.out contains the Edep when the Flexi source is selected. 149 EnergyDeposition_iodine.out contains the Edep when Iodine Bebig Isoseed source is selected. 150 EnergyDeposition_TG186.out contains the Edep when the TG186 source is selected. 151 EnergyDeposition_Leipzig.out contains the Edep when the Iridium source with Leipzig applicator is selected. 152 EnergyDeposition_Oncura.out contains the Edep when the Iodine Oncura 6711 source is selected. 153 154 - brachytherapy.root, containing a 2D histogram with the energy deposition in the phantom. The macro macro.C is provided as example 155 to open brachytherapy.root in ROOT interactive session and to plot the results of the simulation. 156 157 - primary.root, with 1D histogram of the energy spectrum of photons emitted by the radionuclide (see section 4). 158 plot_primary.C is provided as example to open primary.root and to plot the energy spectra 159 160 ------------------------------------------------------------------------------- 161 ----> 8.Visualisation 162 163 A macro is provided ad example of visualisation: VisualisationMacro.mac. 164 165 ------------------------------------------------------------------------------- 166 -----> 9. Comparison to reference data 167 168 The ROOT macros macro.C and plot_primary.C are provided to plot the results of the simulation, contained 169 in the brachytherapy.root file. 170 171 The ROOT macro TG43_relative_dose.C has brachytherapy.root as input file. It calculates the dose rate distribution along the main axis of 172 the brachytherapy source. The dose rate is normalised to 1 at 1 cm distance from the centre. 173 The output file is geant4_dose.txt with two columns: 174 distance from the centre (cm) dose rate distribution 175 176 The user can then compare the dose rate distribution calculated with the example to reference data. 177 178 Directory "comparison": 179 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. 180 181 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. 182 183 The directory "comparison" contains: 184 - the reference data, granero.txt 185 - the data obtained in Geant4.10.3: geant4.txt, 280 M events. geant4.txt is obtained when executing the macro TG43_relative_dose.C 186 - comparison.C - macro to read geant4.txt and granero.txt and compare them in the same plot 187 188 -----> 10. Regression testing of Geant4 189 - the macros to run are in test_macro 190 - the results should be processed with analysis.C 191 192