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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Hello,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">I would suggest you to try the latest Gate release, to start with some example and complexify them step by step to understand what happens.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">In addition, I would suggest to use steps and cuts always lower than the scoring resolution.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Loïc<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Gate-users [mailto:gate-users-bounces@lists.opengatecollaboration.org]
<b>On Behalf Of </b>Theodora Kostou<br>
<b>Sent:</b> Friday, August 11, 2017 12:04 PM<br>
<b>To:</b> gate-users@lists.opengatecollaboration.org<br>
<b>Subject:</b> [Gate-users] Dose Calculation interface problem?<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EL" style="font-size:10.5pt;font-family:"-moz-fixed",serif"><br>
Dear GATE users, <br>
<br>
I am trying to use GATE to calculate the effect of a nanoparticle on the depth-dose curve in radiation therapy. As I was getting incorrect results, I scaled up the problem in order to eliminate possible nano-effects. However, even at the mm level, the problem
still persists. <br>
<br>
It seems to me that there is a problem with geometrical interfaces. Any help would be appreciated.
<br>
<br>
Here is the setup: <br>
<br>
The phantom is a box of water, 20x20x20 mm3 in size. It is irradiated by a 2x2 mm2 square source emitting monoenergetic 140.5 keV photons, placed 2 mm outside the phantom (The small sizes of the phantom and the source are necessary in order to achieve good
statistics when a nanoparticle is inserted in the phantom). Dose is scored in a 200x200x200 matrix. Each voxel is 0.1x0.1x0.1 mm3.
<br>
<br>
Then, I add a 2mm thick layer of water, placed 5 mm below the surface of the phantom, i.e inside the phantom. The depth-dose curve now exhibits two sharp peaks at the location of the interfaces of the water layer and the water phantom (at 4 and 6 mm).
<br>
<br>
The simulations were run on the VIP platform using GATE v6.2. To narrow down the causes I turned off all physical processes, except the Compton effect.
<br>
<br>
Since physically nothing has changed - we are still dealing with a cube of water - I suspect that the cause of the problem is the mere introduction of a new geometrical volume.
<br>
<br>
Has anyone ever encountered this problem? What are the solutions? <br>
<br>
Thank you, <br>
Theodora<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EL" style="font-size:10.5pt;font-family:"-moz-fixed",serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><small><span style=""><o:p></o:p></span><b><span style="font-family: "Verdana","sans-serif"; color: rgb(17, 35, 89);" lang="EN-GB">Disclaimer:</span></b><br>
<span style="font-family: "Verdana","sans-serif"; color: rgb(17, 35, 89);" lang="EN-GB">Please notice our E-Mail Disclaimer <a href="http://www.medaustron.at/email-disclaimer/"><span style="color: rgb(17, 35, 89);">http://www.medaustron.at/email-disclaimer/</span></a></span></small><span style=""><o:p></o:p></span><o:p> </o:p></p>
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