[Gate-users] GATE SPECT simulation: less counts per projection then expected

[David Sarrut]

Hello,

did you perform simulations with Lu177+decay or only gammas (~3%+11% of
decays) ? What kind of source type (point, sphere, voxel ?)

Try to make smaller experiment, with low statistic and without VIP, to
check that everything else seems ok (proportionally).

Sincerely,
David

On Thu, Apr 26, 2018 at 7:48 AM, Niels van der Werf <nrvdwerf at gmail.com>
wrote:

> Dear all,
>
> For my current project I’m trying to simulate the acquisition of
> the Jaszczak phantom filled with 100 MBq Lu-177 on a Symbia SPECT system.
> For this, I use the VIP-network (http://vip.creatis.insa-lyon.fr) where
> the amount of primaries are calculated as time per projection (30s) times
> initial activity. This results in 30x100 000 000 = 3 000 000 000 primaries.
>
> For the Lu-177 activity, I use the MIRD radionuclide data and decay
> schemes, 2nd edition, KF Eckerman & A Endo Eds, The Society of Nuclear
> Medicine, Reston, VA, SNM, 2008, as proposed in several GATE examples.
>
> When this experiment is performed in real life, we get about 14000 counts
> per slice in 30 seconds for the highest photo peak . However, the
> simulation only gives about 1400 counts per slice. So, only about 10% of
> the counts are given for the experiment.
>
> Does anyone have a suggestion where this difference can come from? Thanks
> in advance for your time!
>
> Best regards,
> Niels van der Werf
> Erasmus MC - The Netherlands
>
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>



-- 
David Sarrut, Phd
Directeur de recherche CNRS
CREATIS, UMR CNRS 5220, Inserm U1206
Centre de lutte contre le cancer Léon Bérard
28 rue Laënnec, 69373 Lyon cedex 08
Tel : 04 78 78 51 51 / 06 74 72 05 42
http://www.creatis.insa-lyon.fr/~dsarrut
_________________________________
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