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Hi Simon, </div>
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Thank you for your reply. </div>
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I think I've found the problem - it was due to the incorrect data format when visualizing the reconstructed image. I was using 2 iterations 20 subsets, MLEM, joseph projector, etc during the reconstruction. Please find the attached updated image, I think it
is fine now. <span style="color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; font-size: 12pt;">I'm now planning to perform other corrections, hopefully the scatter and random correction will clean up the reconstructed image and remove the dip
in the center of the attached image.</span></div>
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Could you suggest me which method for scatter correction is relatively easy to implement? I'm thinking about the Single Scatter Simulation method or Triple Energy Window method for it. I would be grateful if you or someone guide me to do it.</div>
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Regards, </div>
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Ashok</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> STUTE Simon <simon.stute@chu-nantes.fr><br>
<b>Sent:</b> Tuesday, July 28, 2020 3:24 AM<br>
<b>To:</b> Tiwari, Ashok <ashok-tiwari@uiowa.edu>; castor-users@lists.castor-project.org <castor-users@lists.castor-project.org><br>
<b>Subject:</b> [External] RE: about counts outside the phantom volume on reconstructed image</font>
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<p>Hi Ashok,</p>
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<p>This is usually normal to have leftover signal outside the object, but it seems that you have more than normal.</p>
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<p>How many iterations did you run ?</p>
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<p>From your image, it seems that you are using a geometry without cylindrical symmetry.</p>
<p>If so, it may be possible that some regions of your field-of-view are not "seen" from a number of different angles that is enough to fully resolve these regions.</p>
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<p>Hope this helps.</p>
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<p>Best</p>
<p>Simon</p>
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<div id="x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>De :</b> Castor-users <castor-users-bounces@lists.castor-project.org> de la part de Tiwari, Ashok <ashok-tiwari@uiowa.edu><br>
<b>Envoyé :</b> dimanche 26 juillet 2020 16:13<br>
<b>À :</b> castor-users@lists.castor-project.org<br>
<b>Objet :</b> [Castor-users] about counts outside the phantom volume on reconstructed image</font>
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Dear CASToR users and developers,</div>
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I've simulated a uniform phantom in GATE and exported the GATE data to CASToR for image reconstruction. During reconstruction, I've chosen only the true events and ran a reconstruction, with and without attenuation correction. Then I visualize the image using
ImageJ (see attached), but I do not understand why counts are appearing outside the phantom volume. Could anyone help me understand why this is happening here? Has anyone seen this before? Is it due to noise and/or scattering outside the phantom?</div>
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Thank you for your help in advance.</div>
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<span style="font-size:12pt; color:rgb(0,0,0)">Regards,</span></p>
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<span style="color:rgb(0,0,0); font-family:Consolas,Courier,monospace; font-size:12pt">Ashok</span></p>
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<span style="color:rgb(23,78,134); font-family:Consolas,Courier,monospace; font-size:12pt">---------------------</span><br>
<span style="color:rgb(23,78,134); font-family:Consolas,Courier,monospace; font-size:12pt">Ashok Tiwari</span><br>
<span style="color:rgb(23,78,134); font-family:Consolas,Courier,monospace; font-size:12pt">Ph.D. Candidate</span><br>
<span style="color:rgb(23,78,134); font-family:Consolas,Courier,monospace; font-size:12pt">Department of Radiology & Physics</span><br>
<span style="color:rgb(23,78,134); font-family:Consolas,Courier,monospace; font-size:12pt">University of Iowa Hospitals and Clinics</span><br>
<span style="color:rgb(23,78,134); font-family:Consolas,Courier,monospace; font-size:12pt">Office: P158, MRF</span><br>
<span style="color:rgb(23,78,134); font-family:Consolas,Courier,monospace; font-size:12pt">200 Hawkins Drive</span><br>
<span style="font-size:12pt; color:rgb(23,78,134); font-family:Consolas,Courier,monospace">Iowa City, </span><span style="font-size:12pt; color:rgb(23,78,134); font-family:Consolas,Courier,monospace">IA </span><span style="font-size:12pt; color:rgb(23,78,134); font-family:Consolas,Courier,monospace">52242</span><br>
<span style="color:rgb(23,78,134); font-family:Consolas,Courier,monospace; font-size:12pt">ashok-tiwari@uiowa.edu</span><br>
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