[Gate-users] Mismatch between LOR and emission points on root output

Enrico Clementel enrico.clementel at ugent.be
Fri May 20 18:33:47 CEST 2011

Dear Gate Users,
I have a problem on both Gate 5.0.0 p1 and Gate 6.0.0 p1 using root output.
I'm simulating a PET scanner using the ECAT structure. Investigating the data we noticed that LORs belonging to True coincidences are very far from the actual emission points.
As an example, I'm attaching a 2D plot of a few events. I simulated a point source in a water cylinder. Blue lines represent LORs, red lines connect the actual emission point to one LOR end. As you can see they are pretty far off.

To ensure I'm considering only Trues, I have the following condition:
if ( comptonCrystal1==0 && comptonCrystal2==0 && comptonPhantom1==0 && comptonPhantom2==0 && eventID1 == eventID2 ) {
before printing the output. LOR ends are obtained from globalPos and the emission point from sourcePos.

Any ideas why this could be happening?
Thank you
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