Fri Feb 5 15:57:27 CET 2016

- You probably want to verify the source geometry using the visualization tools of GATE (/gate/source/[name]/visualize ...) rather than attempting to use a reconstructed image to see if you've set the phantom up the way you want. Reconstruction adds a whole layer of parameters to potentially go wrong. It's possible the problem here is somewhere in the conversion from events to sinograms or in the agreement between the geometry of the scanner you've modelled and the geometry STIR is using in the reconstruction.
- If I've done the calculation correctly, your sphere-to-background activity concentration ratios are 9288:1 and 4227:1. Something less extreme might be easier to visualize.
- Your phantom material is air. Why even bother defining it?
- I think if you want isotropic emission, the min and max thetas and phis already default to 0 and 180 and 360, as necessary.


Laboratoire Imagerie Moléculaire In Vivo (IMIV)
UMR 1023 Inserm/CEA/Université Paris Sud - ERL 9218 CNRS
CEA/I2BM/Service Hospitalier Frédéric Joliot
4, place du Général Leclerc
91401 ORSAY Cedex

<mailto:karima.ait-aissa at cea.fr>
De : gate-users-bounces at lists.opengatecollaboration.org [gate-users-bounces at lists.opengatecollaboration.org] de la part de Lorena Vázquez Canelas [lowry_v_c at hotmail.com]
Envoyé : vendredi 5 février 2016 15:10
À : gate-users at lists.opengatecollaboration.org
Objet : [Gate-users] SOURCE-RECTANGULAR

Hi Gaters,
i made a case very simplified of simulation without forbid comand but the reconstruction is a little strange!


It's only rectangular source (as background) and two spheres of 10 and 13 mm of diameter, but shape according to image is circular and no rectangular.
The output that i have to reconstruct the image is through sinograms to use STIR later.
My code is only the following:

/gate/world/daughters/name                          phantom4
/gate/world/daughters/insert                          box
/gate/phantom4/geometry/setXLength          14. cm
/gate/phantom4/geometry/setYLength          8.3 cm
/gate/phantom4/geometry/setZLength          21.5 cm
/gate/phantom4/placement/setTranslation     0.0 -7.65 0.0 cm
/gate/phantom4/setMaterial                           Air

# Background
/gate/source/addSource                          twogamma
/gate/source/twogamma/setActivity         90 MBq
/gate/source/twogamma/setType             backtoback
/gate/source/twogamma/gps/particle         gamma
/gate/source/twogamma/gps/energytype        Mono
/gate/source/twogamma/gps/monoenergy        0.511 MeV
/gate/source/twogamma/gps/type             Volume
/gate/source/twogamma/gps/shape            Para
/gate/source/twogamma/gps/halfx            7 cm
/gate/source/twogamma/gps/halfy            3.85 cm
/gate/source/twogamma/gps/halfz            10.15 cm
/gate/source/twogamma/gps/centre        0. -7.35 0. cm
/gate/source/twogamma/gps/angtype        iso
/gate/source/twogamma/gps/mintheta        0. deg
/gate/source/twogamma/gps/maxtheta        180. deg
/gate/source/twogamma/gps/minphi        0. deg
/gate/source/twogamma/gps/maxphi        360. deg

# Sphere 10mm diameter:
/gate/source/addSource            10mm
/gate/source/10mm/setActivity         200 MBq
/gate/source/10mm/setType         backtoback
/gate/source/10mm/gps/particle         gamma
/gate/source/10mm/gps/energytype    Mono
/gate/source/10mm/gps/monoenergy    0.511 MeV
/gate/source/10mm/gps/type         Volume
/gate/source/10mm/gps/shape        Sphere
/gate/source/10mm/gps/radius        0.5 cm
/gate/source/10mm/gps/centre        -2.86 -4.954 0. cm
/gate/source/10mm/gps/angtype        iso
/gate/source/10mm/gps/mintheta        0. deg
/gate/source/10mm/gps/maxtheta        180. deg
/gate/source/10mm/gps/minphi        0. deg
/gate/source/10mm/gps/maxphi        360. deg

# Sphere 13 mm diameter:
/gate/source/addSource                    13mm
/gate/source/13mm/setActivity         200 MBq
/gate/source/13mm/setType            backtoback
/gate/source/13mm/gps/particle         gamma
/gate/source/13mm/gps/energytype    Mono
/gate/source/13mm/gps/monoenergy    0.511 MeV
/gate/source/13mm/gps/type         Volume
/gate/source/13mm/gps/shape        Sphere
/gate/source/13mm/gps/radius        0.65 cm
/gate/source/13mm/gps/centre        2.86 -4.954 0. cm
/gate/source/13mm/gps/angtype        iso
/gate/source/13mm/gps/mintheta        0. deg
/gate/source/13mm/gps/maxtheta        180. deg
/gate/source/13mm/gps/minphi        0. deg
/gate/source/13mm/gps/maxphi        360. deg

Do you know what can it happen?
Thanks in advance!!

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