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<TITLE>RE: RE: [Gate-users] [ no subject ]</TITLE>
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<P><FONT SIZE=2>I see.<BR>
<BR>
I downloaded your single_layer.mac and found the problem:<BR>
<BR>
You set your module *readout* depth as 5!<BR>
while benchmarkPET is 1.<BR>
<BR>
Remember in cylindricalPET system:<BR>
<BR>
Level 1: rsector<BR>
Level 2: module<BR>
Level 3: submodule<BR>
Level 4: crystal<BR>
Level 5: layer<BR>
<BR>
What the depth 5 means that you have electronics readout for each layer crystal!<BR>
If you have a penetration or scatter in different crystals for one incident photon,<BR>
you will get multiple pulses there for multiple singles for the same photon.<BR>
That's why you get many intercrystal coincidences.<BR>
<BR>
Now problem is:<BR>
<BR>
1) are you sure you used the same macro for both GATE version (setDepth 5)?<BR>
If yes, that means for some reason that readout (setDepth) module does not work well in old<BR>
GATE.<BR>
<BR>
2) did MJ use the exact same single_layer.mac (setDepth 5)?<BR>
<BR>
No matter what, setDepth 5 is wrong unless you really want to simulate penetration effect.<BR>
<BR>
Please change it to setDepth 1 (or 2 if you have a PMT for each module) and see what you get.<BR>
<BR>
<BR>
Yu Chen, Ph.D.<BR>
University of Massachusetts Medical School<BR>
Division of Nuclear Medicine<BR>
55 Lake Avenue North<BR>
Worcester, MA 01655-0243<BR>
Phone: (508) 856-6123<BR>
Fax: (508) 856-4572<BR>
<BR>
<BR>
<BR>
-----Original Message-----<BR>
From: i.torres@lrz.tu-muenchen.de [<A HREF="mailto:i.torres@lrz.tu-muenchen.de">mailto:i.torres@lrz.tu-muenchen.de</A>]<BR>
Sent: Wed 12/19/2007 2:06 PM<BR>
To: Chen, Yu<BR>
Subject: RE: RE: [Gate-users] [ no subject ]<BR>
<BR>
Hi Yu Chen,<BR>
<BR>
> Do you have the energy plot from single_layer?<BR>
<BR>
I do not have it here. But I send you the results from another GATE user<BR>
that has the same problems. I posted the emails from this GATE user (he<BR>
could not do it), but I am waiting for the administrator approval. You<BR>
will see his emails soon. But in advanced I send you the plots of the<BR>
enery spectra.<BR>
<BR>
> I tend to agree with MJ now that problem may not from GATE.<BR>
<BR>
I do not know where is the problem, but we have the recommended versions<BR>
for CLHEP, Geant, gcc..., the benchmark is fine, but the results from the<BR>
ECAT and single_layer macros are not right... puzzling.<BR>
<BR>
Thank you for you time and help.<BR>
<BR>
Bye,<BR>
<BR>
Irene and Jasmine<BR>
<BR>
</FONT>
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