Monoenergetic proton pencil beam

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</pre>
</pre>
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== How to analyze data ==
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== <span style="color:#000080"> How to analyze data </span> ==
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The macro produces a root file '''Proton.root''' with a 1D histogram showing the energy deposition in
 +
water box along the beam line and another histogram showing zoomed Bragg Peak. It also produces a text file '''DoseFile.txt''' with energy and dose deposited at each slice of the water box. This is an example output
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with the default settings: physics process '''QGSP_BIC_EMY''' and incident proton energy of 62 MeV.
 +
 
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<pre style="color: #800000; background-color: #dcdcdc">
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Cumulated Doses : X[mm]    Edep Edep/Ebeam  Dose
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layer 1: 3.33333 23.1611 GeV 6.22611 % 2.78311e-06 Gy
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layer 2: 6.66667 24.3512 GeV 6.54602 % 2.92612e-06 Gy
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layer 3: 10 25.9655 GeV 6.97998 % 3.1201e-06 Gy
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layer 4: 13.3333 27.6521 GeV 7.43336 % 3.32277e-06 Gy
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layer 5: 16.6667 30.1527 GeV 8.10556 % 3.62325e-06 Gy
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layer 6: 20 33.6152 GeV 9.03635 % 4.03931e-06 Gy
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layer 7: 23.3333 39.396 GeV 10.5903 % 4.73395e-06 Gy
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layer 8: 26.6667 50.3177 GeV 13.5263 % 6.04634e-06 Gy
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layer 9: 30 88.6343 GeV 23.8264 % 1.06506e-05 Gy
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layer 10: 33.3333 2.09587 GeV 0.563405 % 2.51846e-07 Gy
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layer 11: 36.6667 4.59086 MeV 0.0012341 % 5.51653e-10 Gy
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layer 12: 40 0 eV 0 % 0 Gy
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</pre>
 +
 
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You can open Proton.root file in the following way:
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<pre style="color: #800000; background-color: #dcdcdc">
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root -l Gamma.root
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new TBrowser
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</pre>
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Inside is 1D histogram showing the energy deposition in water box:
 +
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[[File:/pbt/RadiotherapyWorkbook/skins/common/images/PhotonPB/Edep.png|Energy deposit per event along the beam]]
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You can change the physics process, incident proton energy and number of slices etc. by
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modifying the macro proton.mac. Use your favorite editor '''pico''', '''vi''', '''emacs''' etc. For example open the macro with editor '''pico''':
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<pre style="color: #800000; background-color: #dcdcdc">
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pico proton.mac
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</pre> 
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This is what you will see:
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<pre style="color: #800000; background-color: #dcdcdc">
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# proton.mac
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#
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/control/verbose 2
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/run/verbose 2
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/tracking/verbose 0
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/run/particle/verbose 1
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/run/particle/dumpList
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#
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# set geometry
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/protonPB/det/setSizeX  4 cm
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/protonPB/det/setSizeYZ 4 cm
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/protonPB/det/setSliceSizeYZ 2 cm
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/protonPB/det/sliceNumber 12
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#
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# set physics process
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/protonPB/phys/addPhysics QGSP_BIC_EMY
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#/protonPB/phys/addPhysics emlivermore
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#/protonPB/phys/addPhysics empenelope
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#
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# production tresholds (recommended range
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#cut off not bigger than 10% of slice thickness)
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/protonPB/phys/setCuts 0.5 mm
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#/protonPB/phys/setGCut 1 um
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#/protonPB/phys/setECut 1 um
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#/protonPB/phys/setPCut 1 um
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#
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# initialize
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/run/initialize
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#
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/gun/particle proton
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# particle energy used in Clatterbridge Centre 
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/gun/energy 62 MeV
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#
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# step limit (recommended not bigger than 5% of
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# slice thickness)
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/protonPB/stepMax 0.2 mm
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#
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/protonPB/event/printModulo 50
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#
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# output file
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/analysis/setFileName Proton
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#
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#
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/analysis/h1/set 2 50 25 35 mm
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# number of events
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/run/beamOn 6000
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#
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</pre>
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=== Change the physics process ===
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The default physics process is '''QGSP_BIC_EMY'''. This is a physics list recommended for proton therapy. You can check what will be the dose deposition if you change the physics list. In proton.mac change
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<pre style="color: #800000; background-color: #dcdcdc">
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/photonPB/phys/addPhysics emstandard_opt0
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</pre>
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to
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<pre style="color: #800000; background-color: #dcdcdc">
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/photonPB/phys/addPhysics emlivermore
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</pre>
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Now run the code:
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<pre style="color: #800000; background-color: #dcdcdc">
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./protonPB proton.mac
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</pre>
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=== Change the incident particle energy ===
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The default energy is 62 MeV. This is one of the energies used in radiotherapy. In proton.mac you can change the value of 62 MeV
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<pre style="color: #800000; background-color: #dcdcdc">
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/gun/energy 20 MeV
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</pre>
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to, for example, 50 MeV
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<pre style="color: #800000; background-color: #dcdcdc">
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/gun/energy 50 MeV
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</pre>
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and run the macro
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<pre style="color: #800000; background-color: #dcdcdc">
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./protonPB proton.mac
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</pre>
 +
 
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=== Change the number of slices ===
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You can change the number of water box slices. The default number is 20. Keep in mind that
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if you want to have more slices you need to modify the file DetectorConstruction.hh in
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/ProtonPB_source/include/.
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In DetectorConstruction.hh change the MaxLayer to a value which is bigger or equal to the
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number of your slices. 
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<pre style="color: #800000; background-color: #dcdcdc">
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const G4int MaxLayer = 10;
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</pre>
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Then in gamma.mac you need to change the number of slices
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<pre style="color: #800000; background-color: #dcdcdc">
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/protonPB/det/sliceNumber 10
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</pre>
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You modified the code therefore you need to comppile it again. In directory PhotonPB_build do
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<pre style="color: #800000; background-color: #dcdcdc">
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make
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</pre>
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then run the macro
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<pre style="color: #800000; background-color: #dcdcdc">
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./protonPB proton.mac
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</pre>
== Comparison with data from The Clatterbridge Cancer Centre ==
== Comparison with data from The Clatterbridge Cancer Centre ==

Revision as of 16:06, 17 July 2014

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