<html><head><style type="text/css"></style></head><body><div style="font-family:times new roman,new york,times,serif;font-size:12pt">Hi, Guocheng, Thank you very much for your response. I'm not sure if I made the same mistake as you. I have changed the library of physical process from "standard" to "lowenergy" but the same thing happened. So I guess that is not the problem. I attached my macro file for all GATE users to review. If you find anything wrong (or suspicious), please let me know. Thanks a lot. <div> </div>Hongwei<div> </div><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"> <div style="font-family: arial,helvetica,sans-serif; font-size: 13px;"><hr size="1">From: WuGuocheng <wuguocheng@neusoft.com> To: howellye@yahoo.com Cc: gate-users@lists.healthgrid.org Sent: Thursday, March 5, 2009 7:24:10 PM Subject: 答复: Gate-users Digest, Vol 34, Issue 4 Hi Hongwei, I also encountered this problem before,  but I can't find the problem, so I attached my macro to help, finally find that the process of physics define error. So, if you haven't resolve the problems, maybe you can attached your macros. And all the gate users will check them for you. Good luck. ---------------------------------------------------------------------- Guocheng Wu Software Department Neusoft Positron Medical Systems Co.,Ltd. No.2 Xin Xiu Street, Hun Nan New District, Shenyang 110179, PRC Tel: (86 24) 836 61980 Fax: (86 24) 836 61796 Mobile: 13604039065 Email: <a ymailto="mailto:wuguocheng@neusoft.com" href="mailto:wuguocheng@neusoft.com">wuguocheng@neusoft.com</a> Website: <a href="http://medical.neusoft.com" target="_blank">http://medical.neusoft.com</a> ---------------------------------------------------------------------- Dear GATE group and users, I found a wield thing when I simulated a LYSO-based PET system: the line source is put out of FOV and inside a polyethylene cylinder. The purpose of this simulation is to find how many scatters come from the source outside FOV. However, some true coincidences (about 1.5%) were found!! I have checked their annihiliation positions using ASCII output and they indeed came from the line source. If I connected two detecors using a line, annihilations CANNOT locate on this line ( not even close to). One example is given below. If you just checked Z positions and you can find the problem: 2.181e+02 for annihilation, 7.711e+01 for one single, and 1.479e+02 for another single. And NO scattering happens before photons entered the detectors. 0  608372    0 9.598e-01 -4.609e+01 2.181e+02 4.68951501753163224606169e+00 6.184e-01 -3.021e+02 -3.291e+02 7.711e+01    0    30    0    0  791 0      0    1    0    0 0.000e+00 0.000e+00      0  608372    0 9.598e-01 -4.609e+01 2.181e+02 4.68951501764343259281986e+00 4.892e-01 4.002e+02 1.912e+02 1.479e+02    0    3    0    0  1026    0 0    0    0    0 0.000e+00 0.000e+00 Could anyone give explainations for this??  Thank you very much. Regards, Hongwei       > > _______________________________________________ > Gate-users mailing list > <a ymailto="mailto:Gate-users@lists.healthgrid.org" href="mailto:Gate-users@lists.healthgrid.org">Gate-users@lists.healthgrid.org</a> > <a href="http://lists.healthgrid.org/mailman/listinfo/gate-users" target="_blank">http://lists.healthgrid.org/mailman/listinfo/gate-users</a> > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <<a href="http://lists.healthgrid.org/archives/gate-users/attachments/20090304/72fa3d" target="_blank">http://lists.healthgrid.org/archives/gate-users/attachments/20090304/72fa3d</a> f8/attachment-0001.htm> ------------------------------ _______________________________________________ Gate-users mailing list <a ymailto="mailto:Gate-users@lists.healthgrid.org" href="mailto:Gate-users@lists.healthgrid.org">Gate-users@lists.healthgrid.org</a> <a href="http://lists.healthgrid.org/mailman/listinfo/gate-users" target="_blank">http://lists.healthgrid.org/mailman/listinfo/gate-users</a> End of Gate-users Digest, Vol 34, Issue 4 ***************************************** --------------------------------------------------------------------------------------------------- Confidentiality Notice: The information contained in this e-mail and any accompanying attachment(s) is intended only for the use of the intended recipient and may be confidential and/or privileged of Neusoft Corporation, its subsidiaries and/or its affiliates. If any reader of this communication is not the intended recipient, unauthorized use, forwarding, printing,  storing, disclosure or copying is strictly prohibited, and may be unlawful.If you have received this communication in error,please immediately notify the sender by return e-mail, and delete the original message and all copies from your system. Thank you. --------------------------------------------------------------------------------------------------- </div></div></div> </body></html>