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GAMOS tutorial RadioTherapy Exercises

GAMOS tutorial RadioTherapy Exercises. Pedro Arce Dubois CIEMAT http://fismed.ciemat.es/GAMOS. Ex. 0: Installation Ex. 1: Basic example Ex. 2: Write and read back a phase space file Ex. 3: Score dose in phantom Ex. 4: optimize simulation The exercises are sequential

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GAMOS tutorial RadioTherapy Exercises

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  1. GAMOS tutorialRadioTherapyExercises Pedro Arce Dubois CIEMAT http://fismed.ciemat.es/GAMOS Introducción a GEANT4

  2. Ex. 0: Installation Ex. 1: Basic example Ex. 2: Write and read back a phase space file Ex. 3: Score dose in phantom Ex. 4: optimize simulation The exercises are sequential Use the commands of the previous exercise (only change what indicated RT simulation Exercises Introducción a GEANT4

  3. Download installation scripts from http://wwwae.ciemat.es/~arce/GAMOS/download/GAMOS.2.0.0/scripts.tgz Uncompress it tar xvzf scripts.tgz Install it (under csh) cd scripts csh source installGamos.csh $HOME/gamos Exercise 0: installation Introducción a GEANT4

  4. Geometry: Tube radius 100cm length 200cm of Water, axis along X inside Box 30cm X 30cm X 40cm of Aluminun Standard electromagnetic physics Primary particle: gamma 10 MeV at (0,0,0) in random direction Exercise 1: simple geometry Introducción a GEANT4

  5. Visualize geometry and tracks Use OGLIX Use VRML2FILE Exercise 1b: visualisation Introducción a GEANT4

  6. Use low energy electromagnetic Use Penelope (Make statistics on processes/particles) Exercise 1c: use different e.m. physics Introducción a GEANT4

  7. TARGET: Box of 4X4X0.5 cm made of copper Placed starting at Z = 0 PRIMARY COLLIMATOR: Tube of radius 10 cm, length 6 cm made of tungsten, with a conical hole of radius 4 to 20 mm Placed starting at Z = 1.6 cm FLATTENING FILTER: Polycone: (Z, R)= (0, 1.25) (10., 9.) (17., 13.8) (17., 27.8) (18., 27.8) made of a mixture of silicon, iron and manganese in equal proportions Placed starting at Z = 8. cm MONITOR: Tube of radius 10 cm, length 3. cm made of a mixture Argon 40% and CO2 60%, density 2.10-3 g/cm3 Placed starting at Z = 13.5 cm JAWS XY: Trapezoids of 10 cm in Z so that they configure a field 40X40 cm made of tungsten Jaws X placed starting at Z = 200 Jaws Y placed starting at Z = 320 RT Exercise 2a: define linac geometry Introducción a GEANT4

  8. Write a phase space file after each of the components of the linac Make plots to see what is stored in the phase space files (particle types, energy, position, direction) Use 10,000 initial histories RT Exercise 2b: Write phase space files Introducción a GEANT4

  9. Use the phase space file generated after the jaws with 10,000 as primary generator Run 100 events, and observe how the particles are reused Force that particles are not reused Recycle full phase space file 10 times Reuse each particle 5 times and use mirroring in X and Y to obtain four different configurations RT Exercise 2c: Read phase space files Introducción a GEANT4

  10. Create a simple phantom of 1X1X1 m Divide in 10X10X100 voxels First ten Z planes of Water, density 1 g/cm3 Second ten Z planes of G4_LUNG_ICRP, density 0.3 g/cm3 Rest of planes of G4_BONE_COMPACT_ICRU, density 1.85 g/cm3 Place it starting at Z = 900 mm RT Exercise 3a: Create simple phantom Introducción a GEANT4

  11. Use a phase space after the jaws, generated with 1,000,000 initial particles Use 10000 events Score dose in each of the phantom voxels Print a report of the dose in each voxel, with errors Make histograms of dose in voxels (PDD, Profile) Write dose in a file, with errors RT Exercise 3b: score dose in phantom Introducción a GEANT4

  12. Repeat exercise 3b using a real phantom: Phantom in EGS format: exercise3_8x8x39.egsphant RT Exercise 3c: use a real phantom Introducción a GEANT4

  13. Define regions for each of the linac parts (target, collimator, flattening filter, monitor and jaws) Get which is the highest cut we can use in each region for electrons and gammas so that we still produce all the particles that would reach the simple phantom Set the cuts and compare time and number of particles in phase space For all these exercises count the time spent per region and per particle/energy interval RT Exercise 4a: optimise production cuts for linac Introducción a GEANT4

  14. Use uniform bremsstrahlung splitting Try splitting 100 times and see bias in phase space Use zplane bremsstrahlung splitting, using as plane the upper plane of the phantom Compare the time and number of particles in phase space Compare the distribution of particles (phase space histos) RT Exercise 4b: use bremsstrahlung splitting Introducción a GEANT4

  15. Define a minimum range user limit equal to one tenth of the minimum of the three voxel dimensions Define a minimum range user limit equal to the minimum of the three voxel dimensions Compare the time and dose histograms Count how many particles are killed RT Exercise 4c: optimise minimum range user limits for phantom Introducción a GEANT4

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