<div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr">Hello Ashok, <br><br>I've attempted the corrections you suggested and am still measuring a dose orders of magnitude above what you measured. Please take a look at the attached code: <br><br><b><u><font color="#ff0000">1) My source file - </font></u></b></div><div dir="ltr"><br><div dir="ltr">#-------------------oooooOOOOO00000OOOOOooooo---------------------#</div><div dir="ltr"><br></div><div dir="ltr"># Example of a radioactive seed within water sphere</div><div dir="ltr"># Output is a 3D dose distribution map (with associated</div><div dir="ltr"># uncertainty) and map of producted C11.</div><div dir="ltr"><br></div><div dir="ltr">#-------------------oooooOOOOO00000OOOOOooooo---------------------#</div><div dir="ltr"><br></div><div dir="ltr"><br></div><div dir="ltr">#=====================================================</div><div dir="ltr"># VERBOSE and VISUALISATION</div><div dir="ltr">#=====================================================</div><div dir="ltr"><br></div><div dir="ltr"># /control/execute mac/verbose.mac</div><div dir="ltr"><br></div><div dir="ltr"># to use the visualisation :</div><div dir="ltr">#  - uncomment the following line</div><div dir="ltr">#  - use Gate --qt</div><div dir="ltr">#  - in the interface, type /control/execute mac/main.mac</div><div dir="ltr"><br></div><div dir="ltr"># /control/execute mac/visu.mac</div><div dir="ltr"><br></div><div dir="ltr"><br></div><div dir="ltr">#=====================================================</div><div dir="ltr"># GEOMETRY</div><div dir="ltr">#=====================================================</div><div dir="ltr"><br></div><div dir="ltr">/gate/geometry/setMaterialDatabase         data/GateMaterials.db</div><div dir="ltr"><br></div><div dir="ltr"># WORLD</div><div dir="ltr">/gate/world/setMaterial           Air</div><div dir="ltr">/gate/world/geometry/setXLength       150 mm</div><div dir="ltr">/gate/world/geometry/setYLength       150 mm</div><div dir="ltr">/gate/world/geometry/setZLength       150 mm</div><div dir="ltr"><br></div><div dir="ltr"># WATERSPHERE</div><div dir="ltr">/gate/world/daughters/name          target</div><div dir="ltr">/gate/world/daughters/insert         sphere</div><div dir="ltr"><br></div><div dir="ltr">#/gate/target/setMaterial           Lead</div><div dir="ltr">#/gate/target/setMaterial           Tungsten</div><div dir="ltr">#/gate/target/setMaterial           Copper</div><div dir="ltr">#/gate/target/setMaterial           Water</div><div dir="ltr">#/gate/target/setMaterial           Air</div><div dir="ltr">/gate/target/setMaterial           Vacuum</div><div dir="ltr">/gate/target/geometry/setRmin        0 mm</div><div dir="ltr">/gate/target/geometry/setRmax        125 mm</div><div dir="ltr">/gate/target/geometry/setPhiStart      0 deg</div><div dir="ltr">/gate/target/geometry/setDeltaPhi      360. deg</div><div dir="ltr">/gate/target/geometry/setThetaStart     0 deg</div><div dir="ltr">/gate/target/geometry/setDeltaTheta     360. deg</div><div dir="ltr">/gate/target/vis/forceWireframe</div><div dir="ltr">/gate/target/vis/setColor          blue</div><div dir="ltr"><br></div><div dir="ltr">#=====================================================</div><div dir="ltr"># PHYSICS</div><div dir="ltr">#=====================================================</div><div dir="ltr"><br></div><div dir="ltr">/gate/physics/addPhysicsList QGSP_BERT_HP_EMY</div><div dir="ltr">/gate/physics/addPhysicsList emstandard</div><div dir="ltr">/gate/physics/addProcess RadioactiveDecay</div><div dir="ltr"><br></div><div dir="ltr">/gate/physics/addProcess Bremsstrahlung e-</div><div dir="ltr">/gate/physics/processes/Bremsstrahlung/setModel StandardModel e-</div><div dir="ltr"><br></div><div dir="ltr">/gate/physics/addProcess MultipleScattering e-</div><div dir="ltr"><br></div><div dir="ltr">/gate/physics/addProcess Compton</div><div dir="ltr">/gate/physics/processes/Compton/setModel StandardModel</div><div dir="ltr"><br></div><div dir="ltr">/gate/physics/displayCuts</div><div dir="ltr">/gate/physics/print output/physics.txt</div><div dir="ltr"><br></div><div dir="ltr"><br></div><div dir="ltr"># ----------------------------------------------------</div><div dir="ltr"># the following actor stores 3D distributions of</div><div dir="ltr"># dose/edep/uncertainty/nbHit into files (mhd image file format)</div><div dir="ltr"><br></div><div dir="ltr">/gate/actor/addActor                DoseActor doseDistribution</div><div dir="ltr">/gate/actor/doseDistribution/save         output/P32_Vacuum.mhd</div><div dir="ltr">/gate/actor/doseDistribution/attachTo       target</div><div dir="ltr">/gate/actor/doseDistribution/stepHitType      random</div><div dir="ltr">/gate/actor/doseDistribution/setSize        250 250 250 mm</div><div dir="ltr">/gate/actor/doseDistribution/setPosition      0 0 0 mm</div><div dir="ltr">/gate/actor/doseDistribution/setVoxelSize     .5 .5 .5 mm</div><div dir="ltr">#/gate/actor/doseDistribution/setResolution     500 500 500    <u>(Note that this Resolution line is commented out, as otherwise Gate throws an error)    </u></div><div dir="ltr">/gate/actor/doseDistribution/enableEdep      false</div><div dir="ltr">/gate/actor/doseDistribution/enableUncertaintyEdep false</div><div dir="ltr">/gate/actor/doseDistribution/enableDose      true</div><div dir="ltr">/gate/actor/doseDistribution/enableSquaredDose   false</div><div dir="ltr">/gate/actor/doseDistribution/enableUncertaintyDose false</div><div dir="ltr">/gate/actor/doseDistribution/enableNumberOfHits  true</div><div dir="ltr">/gate/actor/doseDistribution/saveEveryNSeconds   60</div><div dir="ltr"><br></div><div dir="ltr"><br></div><div dir="ltr">#=====================================================</div><div dir="ltr"># INITIALISATION</div><div dir="ltr">#=====================================================</div><div dir="ltr"><br></div><div dir="ltr">/gate/run/initialize</div><div dir="ltr"><br></div><div dir="ltr">#=====================================================</div><div dir="ltr"># BEAMS</div><div dir="ltr">#=====================================================</div><div dir="ltr"><br></div><div dir="ltr"># Ph 32 source </div><div dir="ltr">/control/execute mac/betaP32.mac</div><div dir="ltr"><br></div><div dir="ltr">#=====================================================</div><div dir="ltr"># START BEAMS</div><div dir="ltr">#=====================================================</div><div dir="ltr"><br></div><div dir="ltr">/gate/random/setEngineName MersenneTwister</div><div dir="ltr">/gate/random/setEngineSeed auto</div><div dir="ltr">/gate/application/setTotalNumberOfPrimaries 10E5</div><div dir="ltr">/gate/application/start</div><div dir="ltr"><br></div><div dir="ltr"><br></div><div><b><u><font color="#ff0000">2) My mac file defining the P32 source as a simple mono energy beta source (I am still rather uncertain as to how to generate a discrete source...)</font></u></b><br><br><div>#Description of Phosphorus 32 beta source</div><div><br></div><div># Add beta source </div><div><br></div><div>/gate/source/addSource P32_beta gps</div><div>/gate/source/P32_beta/setActivity 30000. Bq</div><div>/gate/source/P32_beta/gps/particle e-</div><div>/gate/source/P32_beta/gps/energy 1.709 MeV</div><div>/gate/source/P32_beta/gps/hist/type energy</div><div>/gate/source/P32_beta/setForcedUnstableFlag true</div><div>/gate/source/P32_beta/setForcedHalfLife 1232755 s</div><div><br></div><div># /gate/source/P32_beta/gps/hist/point 0 0.0</div><div>/gate/source/P32_beta/gps/position 0 0 0 cm</div><div>/gate/source/P32_beta/gps/shape Sphere</div><div>/gate/source/P32_beta/gps/radius 0.012 mm</div><div><br></div><div># Set angular distribution of beta emission</div><div>/gate/source/P32_beta/gps/angtype iso</div></div><div><br></div><div><br>Thank you for your assistance, <br><br>Chris</div><div><br></div></div></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Jan 24, 2019 at 5:01 PM Ashok Tiwari <<a href="mailto:tiwarias@yahoo.com">tiwarias@yahoo.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi Chris, <br>
<br>
First, it would be easy for us if you copy-paste the part of your macro instead of attaching images.<br>
<br>
Size of the dose actor is different than the size of the spherical phantom (say target according to your macro), but you have to set the size of actor (setSize parameter) is equal to size of sphere, so that you can store all the dose informations up to the boundary of the sphere. Therefore, diameter of spherical volume would be equal = Resolution of matrix * voxel size. In other words, setSize of dose actor = resolution * voxel size.<br>
<br>
Yes, we need to attach dose actor to the center of spherical volume. You did it correctly. <br>
<br>
Your dose actor seems ok. Now, you can check:<br>
1. the radius of the sphere, I suggest you to put 125 mm as its radius (0.5*500=250, 250/2=125)<br>
2. Source: use discrete spectrum of P-32 beta emitter<br>
3. You may want to save your dose matrix at every 60 seconds instead 20 to lessen the simulation time<br>
4. One more important thing: if you want to have particle interaction in each voxel volume (many authors defined this volume as a dosel) then set step size as 0.5 mm and activate the step limiter parameter. <br>
<br>
Try these things, if these does not work then send me your main macro, I will take a look.<br>
<br>
Thanks, <br>
Ashok</blockquote></div>