<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div>Dear GATE users,<br><div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div><br></div><div>I am having the same problem as Yannick Berker described on 2011-10-21. I use the ImageNestedParametrisedVolume phantom for a PET simulation. The sources are described using interfiles. Everything seems to be working correctly, i.e. the sources and phantom are in the right place and coincidences are detected. The effect of phantom attenuation is also clearly visible.</div><div><br></div><div>The problem that I’m having, is that in the ROOT coincidences tree there is no comptonPhantom and RayleighPhantom data. I cannot add the VoxelPhantomSD to the ImageNestedParametrisedVolume, because I get an error message saying the command is unavailable. I can add the ordinary PhantomSD, but this does not seem to add the comptonPhantom or RayleighPhantom information to the coincidence tree. The comptonCrystal and RayleighCrystal entries are correct, so I think the physics processes are registered and working correctly. </div><div><br></div><div>I need the comptonPhantom and RayleighPhantom information to get scatter information on coincidences.</div><div><br></div><div>Did anyone else come across this problem, and if so, how did you solve it? Or can anyone point me in the direction of a solution?</div><div><br></div><div>Regards,</div><div><br></div><div>Tom Buitenhuis</div><div><br></div><div>PhD student</div><div>KVI - Center for Advanced Radiation Technology</div><div>University of Groningen</div><div>The Netherlands</div><div><pre></pre></div><span></span><br><blockquote type="cite"><pre>Dear GATE users,
I have some issues using the HounsfieldMaterialGenerator to simulate a PET scan of a patient. The
simulation itself is running fine, but I am lacking two features that I am used to from other simulations,
which are scatter information and color visualization. I mainly used the example from
<a rel="nofollow" href="http://www.creatis.insa-lyon.fr/gate/Example2/" target="_top" style="color: rgb(0, 35, 144); font-weight: bold; text-decoration: none;">http://www.creatis.insa-lyon.fr/gate/Example2/</a> to generate the following phantom:
/gate/HounsfieldMaterialGenerator/SetMaterialTable CT/Schneider2000MaterialsTable.txt
/gate/HounsfieldMaterialGenerator/SetDensityTable CT/Schneider2000DensitiesTable.txt
/gate/HounsfieldMaterialGenerator/SetDensityTolerance 0.03 g/cm3
/gate/HounsfieldMaterialGenerator/SetOutputMaterialDatabaseFilename CT/p971-HUmaterials.db
/gate/HounsfieldMaterialGenerator/SetOutputHUMaterialFilename CT/p971-HU2mat.txt
/gate/HounsfieldMaterialGenerator/Generate
/gate/world/daughters/name patient
/gate/world/daughters/insert ImageRegionalizedVolume
/gate/geometry/setMaterialDatabase CT/p971-HUmaterials.db
/gate/patient/geometry/SetHUToMaterialFile CT/p971-HU2mat.txt
/gate/patient/geometry/SetImage CT/p971s3.hdr
...
The ROOT output shows me that the volume is placed correctly, and the distribution of detected
coincidences also shows the effect of photon attenuation by the phantom. However, I cannot attach a
<b style="background-color: rgb(255, 255, 102);">VoxelPhantomSD</b> to the patient - I receive an error message telling me that this command is unavailable:
[G4-cerr] <b>**</b>*<b>**</b> COMMAND NOT FOUND </gate/patient/attach<b style="background-color: rgb(255, 255, 102);">VoxelPhantomSD</b>> <b>**</b>*<b>**</b>
Attaching an ordinary PhantomSD seems to work, but only generates 0 entries in ComptonPhantom and
RayleighPhantom. I also tried using a ImageNestedParametrisedVolume, with no effect. ComptonCrystal
entries, however, seem to be correct (>= 0).
Apart from that, how can I visualize the voxelized phantom using colors? I was not able to add color
attributes (like "true 0.5 0.5 0.5 1.0") to p971-HU2mat.txt manually, since this resulted in the
following error message:
src/<a href="http://gatevimagevolume.cc/">GateVImageVolume.cc</a> (l.332): No Hounsfield material defined in the file
CT/p971s3_ToSim_OneBP_HU2mat_Colors.txt. Abort
Does anyone have knowledge in this area, or can point to some helpful documentation on this topic? The GATE
User's Guide has a few, but only incomplete examples for the case of voxelized phantoms and sources.
Best regards,
Yannick Berker
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