<!doctype html public "-//W3C//DTD W3 HTML//EN"> <html><head><style type="text/css"></style><title>Fwd: FW: Difference in energy spectrum for first and s</title></head><body> <blockquote type="cite" cite>X-Ids: 165 X-Greylist: delayed 857 seconds by postgrey-1.21 at ns2919.ovh.net; <x-tab>   </x-tab>Sat, 25 Aug 2007 00:17:05 CEST X-IronPort-AV: E=Sophos;i="4.19,305,1183352400"; <x-tab>  </x-tab >d="mac'?jpg'145?scan'145,208,217,145";a="310266" Subject: FW: Difference in energy spectrum for first and second event in <x-tab>        </x-tab>cylindrical PET system Date: Fri, 24 Aug 2007 16:54:28 -0500 Thread-Topic: Difference in energy spectrum for first and second event in <x-tab>    </x-tab>cylindrical PET system Thread-Index: Acfmlfu0s1jG3B4WQ1WCyGHMNxLkBQAAzp2w From: "Andrew Goertzen" <AGoertzen2@exchange.hsc.mb.ca> To: <gate-users-owner@lists.healthgrid.org> X-OriginalArrivalTime: 24 Aug 2007 21:54:28.0267 (UTC) <x-tab>        </x-tab>FILETIME=[57E9BFB0:01C7E699] Sender: mailman-bounces@lists.healthgrid.org X-Virus-Scanned: ClamAV 0.88.7/4054/Fri Aug 24 18:55:59 2007 on shiva.jussieu.fr X-Virus-Status: Clean X-Miltered: at shiva.jussieu.fr with ID 46CF5710.007 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! </blockquote> <blockquote type="cite" cite>The following message was rejected by the address 'gate-users@lists.healthgrid.org'.  Could you please post it on my behalf? </blockquote> <blockquote type="cite" cite>Thanks, Andrew </blockquote> <blockquote type="cite" cite> </blockquote> <blockquote type="cite" cite>Hi All, </blockquote> <blockquote type="cite" cite>I am simulating a cylindrical PET system in GATE 3.0.0 with the geometry of a microPET R4 and I am hoping someone can help explain the behaviour I am seeing.  My source is a 1.25 MBq line source at the centre of the FOV.  Data is written to an ASCII text file.  When I create an energy histogram from the coincidence data output file I notice that the events identified as 'single 1' in a coincidence event (i.e. columns 1-21 of a coincident event in ascii format as described in section 10.1 of the user manual) have a different energy spectrum than events identified as 'single 2'.  I have included an example of this in the attached jpg image.  I do not think it is time related because I get this behaviour with and without 1.5ns of time blurring.  Also, the timestamp for single 1 is not always less than for single 2.  I do not think it is energy related because the energy of single 1 is neither always greater than or always less than single 2. </blockquote> <blockquote type="cite" cite>So I am hoping that someone can answer the following questions: How does GATE determine the order of singles that make up a coincident event? Has anyone else observed this sort of difference between the first and second single? </blockquote> <blockquote type="cite" cite>I have included the .mac file I am using. </blockquote> <blockquote type="cite" cite>Regards, Andrew Goertzen Department of Radiology University of Manitoba </blockquote> <blockquote type="cite" cite><<EnergyHistogram.jpg>> <<microPETR4.mac>> </blockquote> <blockquote type="cite" cite> Content-Type: image/jpeg; <x-tab>       </x-tab>name="EnergyHistogram.jpg" Content-Description: EnergyHistogram.jpg Content-Disposition: attachment; <x-tab>      </x-tab>filename="EnergyHistogram.jpg" Content-Type: application/octet-stream; <x-tab>   </x-tab>name="microPETR4.mac" Content-Description: microPETR4.mac Content-Disposition: attachment; <x-tab>        </x-tab>filename="microPETR4.mac" This email and/or any documents in this transmission is intended for the addressee(s) only and may contain legally privileged or confidential information.  Any unauthorized use, disclosure, distribution, copying or dissemination is strictly prohibited.  If you receive this transmission in error, please notify the sender immediately and return the original. Ce courriel et tout document dans cette transmission est destiné à la personne ou aux personnes à qui il est adressé. Il peut contenir des informations privilégiées ou confidentielles. Toute utilisation, divulgation, distribution, copie, ou diffusion non autorisée est strictement défendue. Si vous n'êtes pas le destinataire de ce message, veuillez en informer l'expéditeur immédiatement et lui remettre l'original.</blockquote> <div> </div> <div> </div> <x-sigsep><pre>-- </pre></x-sigsep> <div>Irene Buvat, PhD Equipe "Imagerie de la perfusion et des échanges moléculaires" U678 INSERM CHU Pitié Salpêtrière 91 Boulevard de l'Hôpital 75634 Paris Cedex 13 France Tel : 01 53 82 84 19 Fax : 01 53 82 84 48 email : buvat@imed.jussieu.fr http://www.guillemet.org/irene</div> </body> </html>