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--></style></head><body lang=EN-US link=blue vlink="#954F72"><div class=WordSection1><p class=MsoNormal>My fellow Gate Users, <br><br>I’m running SPECT simulations for different collimator settings. To see the image formed on the SPECT pixel array, I use two different strategies: </p><p class=MsoNormal><o:p> </o:p></p><ol style='margin-top:0in' start=1 type=1><li class=MsoListParagraph style='margin-left:0in;mso-list:l0 level1 lfo1'>Interfile Image via <i>/gate/output/projection</i></li><li class=MsoListParagraph style='margin-left:0in;mso-list:l0 level1 lfo1'>Post-Processing ASCII SPECT Singles file</li></ol><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>What I notice is that the image built from the Interfile does not match the post-processing of the Singles data, and I’m a little confused then as to why this is. One question that would clear that up, what exactly does the interfile image projection represent? <br><br>As I understand it, Singles represent the physical observables from the simulation, in this case the number of pulses that particles trigger in each pixel. Values are similar, but different between the two methods, wherein the Singles files gives me a total of 1169 triggered pulses, and the Interfile gives me 1159…units of something. This clearly isn’t a huge difference, but I would have expected them to be the same. So for my own understanding, does anyone know what exactly the Interfile Projection values represent? Are they Singles? <br><br>Thank you! <br><br>Chris</p><p class=MsoNormal><o:p> </o:p></p></div></body></html>