<html> <head> <style></style></head> <body class='hmmessage'><div dir='ltr'>Dear Gate user and developers, I'm learning to use vGate 3.0 and simulate the SPECT system, but I cannot figure out which value is the counts detected by a real detector (crystalSD hits?) from the ASCII output. My simulation is based on the SPECT benchmark example, and both crystal sensitive detector (crystalSD) and phantom sensitive detector (phantomSD) are set as follows. # Crystal SD /gate/crystal/attachCrystalSD # Phantom SD /gate/Phantom/attachPhantomSD /gate/movsource/attachPhantomSD /gate/table/attachPhantomSD /gate/compartment/attachPhantomSD /gate/shielding/attachPhantomSD /gate/SPECThead/attachPhantomSD /gate/collimator/attachPhantomSD According to the user guide V7.0, hits output file (gateHITs.dat) includes number of Compton and Rayleigh interactions only in phantoms ( Q1: does it mean phantom SD?) before reaching the detector( Q2: does it mean phantom SD, too?), which are shown in columns N+15 and N+16. I think a Hit stands for a trajectory step within any sensitive detector, why are the hits (interactions in crystals) of crystalSD not given? (Q3) For singles output file (gatesingles.dat). As I use both crystalSD and phantomSD, and the readout module of digitization is chosen by default, does it mean that I'll get two kinds of singles corresponding to the two separate sensitive detectors after this digitization?(Q4) According to the user guide V7.0, singles output file includes "Number of Compton interactions in detectors before reaching the detector", here what's the difference between those two 'detectors'?(Q5) From this output, which value means counts detected by the crystalSD?(Q6) Also, based on the interfile output of projection set, does the .sin file show us the image contains the real detector counts only?(Q7) Sorry for so many stupid questions, but I do want to learn from you guys! Thanks, Jin </div></body> </html>