[Gate-users] Inconsistent energy spectra with multiple sources

[Débora Salvado]

Hi Fernando

Thanks for your answer!

In fact, I don't define any deadtime in my digitizer, it's just:

/gate/digitizer/Singles/insert adder
/gate/digitizer/Singles/insert blurring
/gate/digitizer/Singles/blurring/setResolution 0.1
/gate/digitizer/Singles/blurring/setEnergyOfReference 122. keV
/gate/digitizer/Singles/insert spblurring
/gate/digitizer/Singles/spblurring/setSpresolution 0.8 mm
/gate/digitizer/Singles/spblurring/verbose 0

Does it mean there is a "default" deadtime that I wasn't accounting for?

Regards,

Debora Salvado, MSc
PhD Student
University College London
INM, UCLH, (T-5) 235 Euston Road
London NW1 2BU
UK

2015-04-20 16:34 GMT+01:00 Fernando Rannou <fernando.rannou at usach.cl>:

> Just wondering whether deadtime effects have to do anything with it.
> If you have more activity...
>
> Fernando
>
> On Fri, Apr 17, 2015 at 3:54 PM, Débora Salvado <debbiesal at gmail.com>
> wrote:
> > Dear GATE users
> >
> > I have a SPECT setup as exemplified in the attached file setup.png
> >
> > I run different simulations:
> > 1) I123 (159 and 529keV) 185MBq in the patient volume
> > 2) Lu176 (88, 200 and 300keV) 5.6MBq in the LSO volume
> > 3) I123 185MBq and Lu176 5.6MBq in the respective volumes
> >
> > In the file energySpectra.png, I show you the energy spectra obtained
> when
> > running every simulation for 1 minute. Can someone explain me why the
> dashed
> > and the black energy spectra are different?
> > The dashed spectrum is just a sum of the red and green data series.
> >
> > In my opinion, the proportion of the peaks in the black spectrum seems
> > correct (simulation with both sources), but then why doesn't it
> correspond
> > to the sum of the counts obtained in separate simulations with only one
> of
> > the sources?
> >
> > Any suggestions?
> >
> > Regards,
> > Débora
> >
> > Debora Salvado, MSc
> > PhD Student
> > University College London
> > INM, UCLH, (T-5) 235 Euston Road
> > London NW1 2BU
> > UK
> >
> > _______________________________________________
> > Gate-users mailing list
> > Gate-users at lists.opengatecollaboration.org
> > http://lists.opengatecollaboration.org/mailman/listinfo/gate-users
>
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