<div dir="ltr"><div><font size="4">Dear Gate users,</font></div><div><font size="4">I am trying to calculate the dose for the CT based Phantom (512x512x361 matrix) using a proton beam. I read dicom images directly and define the HU to material conversion file. I am using the vGate.8 virtual machine.<br></font></div><div><font size="4"><b><span style="color:rgb(255,0,0)">Problem:</span></b> If I define only three materials (vacuum, Air and TissueEquivalent ) the simulation gives output for 1000 primaries very fast in a couple of seconds and I can get the output. But if I define one extra material (any material, I have tried different materials) , let say (Vacuum, Air, TissueEquvalent, Liver) the simulation runs for a very very long time even for 1 primary particle (Actually does not finish even in 10 hours). Can you give me some suggestions to fix the problem. What is the possible cause of the problem? There seems to be something wrong with my approach. I have shared my code below. I have 306 Dicom images put in a single directory. <br></font></div><div><font size="4"><span style="color:rgb(0,0,255)">Definition of the HUToMat.txt </span><br></font></div><br><div><font size="4">-2000 -800  Vacuum<br>-800  -40   Air<br>-40   200  Blood<br>200   19000 TissueEquivalent</font></div><div><font size="4"><br></font></div><div><font size="4"><span style="color:rgb(0,0,255)">#CODE</span><br></font></div><div><span style="color:rgb(255,0,0)">/<b><font size="4">control/execute mac/verbose.mac<br>/gate/geometry/setMaterialDatabase     data/GateMaterials.db<br></font></b></span></div><div><span style="color:rgb(255,0,0)"><b><font size="4"><span style="color:rgb(0,0,255)">#WorldVolume</span><br></font></b></span></div><div><span style="color:rgb(255,0,0)"><b><font size="4">/gate/world/setMaterial              Vacuum<br>/gate/world/geometry/setXLength      100 cm<br>/gate/world/geometry/setYLength      100 cm<br>/gate/world/geometry/setZLength      100 cm<br><br>/gate/world/daughters/name          Pat<br>/gate/world/daughters/insert          box<br>/gate/Pat/geometry/setXLength       32 cm<br>/gate/Pat/geometry/setYLength       32 cm<br>/gate/Pat/geometry/setZLength       32 cm</font></b></span></div><div><span style="color:rgb(255,0,0)"><b><font size="4"><span style="color:rgb(0,0,255)">#Daughter for DICOM</span><br></font></b></span></div><div><span style="color:rgb(255,0,0)"><b><font size="4">/gate/Pat/daughters/name            Volume<br>/gate/Pat/daughters/insert         ImageRegularParametrisedVolume #    ImageNestedParametrisedVolume <br></font></b></span></div><div><span style="color:rgb(255,0,0)"><b><font size="4">#CoversionFile<br></font></b></span></div><div><span style="color:rgb(255,0,0)"><b><font size="4">/gate/Volume/geometry/setHUToMaterialFile    data/HUToMat.txt </font></b></span></div><div><b><font size="4"><span style="color:rgb(255,0,0)">/gate/Volume/geometry/setImage        New_CODE/data/dcm/1.dcm #<br>/gate/Volume/placement/setRotationAxis      0 -1 0<br>/gate/Volume/placement/setRotationAngle     90 deg<br>/gate/Volume/setSkipEqualMaterials  1<br></span></font></b></div><div><b><font size="4"><span style="color:rgb(255,0,0)"><br></span></font></b></div><div><b><font size="4"><span style="color:rgb(255,0,0)"><span style="color:rgb(0,0,255)">#SIMPLEDOSEActor</span><br></span></font></b></div><div><b><font size="4"><span style="color:rgb(255,0,0)">/gate/actor/addActor                              DoseActor  doseDistribution_text<br>/gate/actor/doseDistribution_text/save          output/Dose_Map_Energy_MeV_1D_5material.root<br>/gate/actor/doseDistribution_text/attachTo        Volume #PMMA_Block<br>/gate/actor/doseDistribution_text/stepHitType      random<br>/gate/actor/doseDistribution_text/setSize        300 300 300 mm<br>/gate/actor/doseDistribution_text/setResolution     1280 1 1<br>/gate/actor/doseDistribution_text/enableEdep       true<br>/gate/actor/doseDistribution_text/enableUncertaintyEdep true<br>/gate/actor/doseDistribution_text/enableDose       true<br>/gate/actor/doseDistribution_text/enableUncertaintyDose true<br>/gate/actor/doseDistribution_text/enableNumberOfHits   true</span></font></b></div><div><b><font size="4"><span style="color:rgb(255,0,0)"><br></span></font></b></div><div><b><font size="4"><span style="color:rgb(255,0,0)"><span style="color:rgb(0,0,255)">#PhysicsList</span><br>/gate/physics/addPhysicsList QGSP_BIC_HP_EMZ<br><span style="color:rgb(0,0,255)">#Cuts</span><br>/gate/physics/Gamma/SetCutInRegion   world 10 mm<br>/gate/physics/Electron/SetCutInRegion   world 10 mm<br>/gate/physics/Positron/SetCutInRegion   world 10 mm<br>/gate/physics/Proton/SetCutInRegion     world 10 mm<br>/gate/physics/Gamma/SetCutInRegion   Pat 1 mm<br>/gate/physics/Electron/SetCutInRegion   Pat 1 mm<br>/gate/physics/Positron/SetCutInRegion   Pat 1 mm<br>/gate/physics/Proton/SetCutInRegion     Pat 1 mm<br>/gate/physics/SetMaxStepSizeInRegion   Pat 1 mm<br>/gate/physics/ActivateStepLimiter proton<br>/gate/physics/displayCuts</span></font></b></div><div><b><font size="4"><span style="color:rgb(255,0,0)"><br></span></font></b></div><div><b><font size="4"><span style="color:rgb(255,0,0)">/gate/run/initialize<br>/gate/random/setEngineName MersenneTwister<br>/gate/random/setEngineSeed auto<br><span style="color:rgb(0,0,255)">#Source</span><br>/gate/source/addSource PBS PencilBeam<br>/gate/source/PBS/setParticleType proton<br>/gate/source/PBS/setEnergy 90 MeV<br>/gate/source/PBS/setSigmaEnergy .88 MeV<br>/gate/source/PBS/setPosition 0 0 -36.5 cm <br>/gate/source/PBS/setSigmaX 3.0 mm <br>/gate/source/PBS/setSigmaY 3.0 mm <br>#/gate/source/PBS/setRotationAxis 0 1 0<br>#/gate/source/PBS/setRotationAngle 90 deg<br>/gate/source/PBS/setSigmaTheta 20 mrad<br>/gate/source/PBS/setSigmaPhi  20 mrad <br>/gate/source/PBS/setEllipseXThetaEmittance 40 mm*mrad #40 mm*mrad, 2mm*mrad<br>/gate/source/PBS/setEllipseYPhiEmittance  40 mm*mrad #40 mm*mrad, 2mm*mrad<br>#positive-> converging beam; negative diverging beam<br>/gate/source/PBS/setEllipseXThetaRotationNorm positive<br>/gate/source/PBS/setEllipseYPhiRotationNorm  positive<br>/gate/application/setTotalNumberOfPrimaries 1000 <br>/gate/application/start</span></font></b></div><div><b><font size="4"><span style="color:rgb(255,0,0)"><br></span></font></b></div><div><span style="color:rgb(0,0,0)"><b><font size="4">I have dumped this file into single density (.mhd +.raw) format and tried to read it from a single density file but it has no difference in performance. Below is the information in the header file.</font></b></span></div><div><b><font size="4"><span style="color:rgb(255,0,0)"><br></span></font></b></div><div><b><font size="4"><span style="color:rgb(255,0,0)">ObjectType = Image<br>NDims = 3<br>BinaryData = True<br>BinaryDataByteOrderMSB = False<br>CompressedData = False<br>TransformMatrix = 1 0 0 0 1 0 0 0 1<br>Offset = -151.494 -36.6564 1115<br>CenterOfRotation = 0 0 0<br>ElementSpacing = 0.589844 0.589844 0.5<br>DimSize = 512 512 361<br>AnatomicalOrientation = ???<br>ElementType = MET_FLOAT<br>ElementDataFile = density-ffs-dcm_5mat.raw<br></span></font></b></div><div><span style="color:rgb(68,68,68)"><b><font size="4">Please ask me any further details if you feel anything ambiguous. Your suggestions and solutions are needed. Thank you in advance!<br></font></b></span></div><div><span style="color:rgb(68,68,68)"><b><font size="4">Regards</font></b></span></div><div><b><font size="4"><span style="color:rgb(255,0,0)"><span style="color:rgb(68,68,68)">Atiq</span><br></span></font></b></div><div><b><font size="4"><span style="color:rgb(255,0,0)"><br> </span></font></b></div></div>