<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi,<div><br></div><div>Could anyone explain the organization of sinogram output from  " <span class="Apple-style-span" style="font-family: 'Lucida Grande'; ">PET_Ecat_System.mac " example, please? </span></div><div><span class="Apple-style-span" style="font-family: 'Lucida Grande'; ">A 32 ring system generates 1024 2D sinograms, and they must be indexed by ring difference ( Ri - Rj) and axial position (Ri + Rj)/2 according to the info file and the Gate manual. However, i couldn't even figure out which ones are direct sinograms ( Ri - Rj =0) out of these 1024 sinograms. </span></div><div><font class="Apple-style-span" face="'Lucida Grande'"><br></font></div><div><font class="Apple-style-span" face="'Lucida Grande'">I tried to understand the organization by simulating the acquisition from sources at different locations and shapes; decreasing ring number but still couldn't solve this except that i can see a pattern due to ring difference indexing, when i plot the total counts of the sinograms...What other approach would you recommend to figure out the data organization?</font></div><div><font class="Apple-style-span" face="'Lucida Grande'"><br></font></div><div><font class="Apple-style-span" face="'Lucida Grande'">Thanks,</font></div><div><font class="Apple-style-span" face="'Lucida Grande'">arda konik</font></div><div><font class="Apple-style-span" face="'Lucida Grande'">University of Iowa</font></div></body></html>