[Gate-users] question about the coincidence window

[Fernando Rannou]

I think this is them method we are interested in:

inline G4bool GateCoincidencePulse::IsInCoincidence(const GatePulse*
newPulse) const
{
   return    ( size()==0 )
           ||
	     (  (newPulse->GetTime()>=m_startTime+m_offsetWindow)
	       &&
	        (newPulse->GetTime()< (m_startTime+m_offsetWindow
+m_coincidenceWindow))
	     );
}

Fernando

On Thu, 2007-04-26 at 12:58 -0400, Chen, Yu wrote:
> Then it is an assue about GATE implementation not
> consistent with standard definition in any of paralyzable
> or nonparalyzable model?
> 
> If it is true, I am fortunate to use my own code to avoid this
> inconsistence.
> 
> Thanks,
> 
> Yu Chen, Ph.D.
> University of Massachusetts Medical School
> Division of Nuclear Medicine
> 55 Lake Avenue North
> Worcester, MA 01655-0243
> Phone:  (508) 856-6123
> Fax:    (508) 856-4572
> 
> 
> 
> -----Original Message-----
> From: Fernando Rannou [mailto:rannou at diinf.usach.cl]
> Sent: Thu 4/26/2007 12:28 PM
> To: Chen, Yu
> Cc: yuxuan.zhang at di.mdacc.tmc.edu; gate-users at lists.healthgrid.org
> Subject: RE: [Gate-users] question about the coincidence window
> 
> This issue was discussed 3 years ago. I asked a very similar
> question when I wanted to compare random rates using two approaches.
> 
> If an event arrives at time t, then a coincidence will be
> counted for en event in [t-tau] or [t+tau] but not [t+2tau] or
> [t-2tau]
> 
> 
> Fernando Rannou
> 
> On Thu, 2007-04-26 at 12:14 -0400, Chen, Yu wrote:
> > Hi, Yuxuan,
> >
> > nice question.
> > I have not any experience on coincidence package in GATE since
> > I use our standalone coincidence program from GATE singles output,
> and
> > we can have complete control such as choosing of paralyzable or
> > nonparalyzable
> > model.
> >
> > In my opinion, coincidence window is an very important parameter in
> > any
> > coincidence experiment. It must be allowed to easily changed by
> users
> > either
> > for GATE or for any specific PET scanner.
> >
> > I do not completely understand what you said here for single pulse
> > width.
> >
> > Do you talk about width of two singles or coincidence output signal?
> >
> > If about width of single photon pulse, I do not think this width
> > should be
> > directly associated with coincidence window. As I know, GATE only
> > gives a time stamp
> > to any particular singles since no electronics response is simulated
> > in GATE.
> >
> > If about width of coincidence signal, why are you bothered with it?
> > What you need is
> > a count which is only dependent on coincidence window and model in
> > GATE, and of course
> > in real scanner also dependent on the width of two single pulses. As
> > long as you set
> > your coincidence window greater than twice of single pulse width,
> > coincidence count would
> > be no longer dependent on single pulse width. 
> >
> > For GATE application, what you need to do is to use the same
> > parameters from your real scanner,
> > e.g., 10 ns coincidence window, paralyzable model to get the same
> > results.
> >
> > Hope it helps.
> >
> > Yu Chen, Ph.D.
> > University of Massachusetts Medical School
> > Division of Nuclear Medicine
> > 55 Lake Avenue North
> > Worcester, MA 01655-0243
> > Phone:  (508) 856-6123
> > Fax:    (508) 856-4572
> >
> >
> >
> > -----Original Message-----
> > From: gate-users-bounces at lists.healthgrid.org on behalf of
> > yuxuan.zhang at di.mdacc.tmc.edu
> > Sent: Wed 4/25/2007 6:35 PM
> > To: gate-users at lists.healthgrid.org
> > Subject: [Gate-users] question about the coincidence window
> >
> > hi All,
> >
> > I have a question about the definition of the coincidence time
> window,
> > which might be
> > different among the GATE society and the nuclear electronics people.
> >
> > According to the GATE user's manual, the coincidence window is the
> > width
> > of the single pulse,
> > however, according to some literature and electronics engineering
> > people,
> > the coincidence windows
> > are defined as twice of the width of the single pulse. So if they
> say
> > one
> > PET camera has a
> > coincidence window of 10 ns, this should mean that the width of the
> > single
> > pulse is 5 ns.
> > If this is the case, then we should setup the coincidence window in
> > GATE
> > simulation as 5 ns
> > rather than 10 ns.
> >
> > I've checked several published papers about the validation of the
> > GATE, no
> > one has made any comment
> > on this issue explicitly. So I brought this to you attention and
> hope
> > you
> > can give some comments.
> >
> > Best regards,
> >
> > Yuxuan
> >
> >
> >
> >
> >
> > --
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> > Gate-users at lists.healthgrid.org
> > http://lists.healthgrid.org/mailman/listinfo/gate-users
> 
> 
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> 
> 
> 
> 
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Este mensaje ha sido analizado por MailScanner
en busca de virus y otros contenidos peligrosos,
y se considera que está limpio.
MailScanner agradece a transtec Computers por su apoyo.