[Gate-users] Fwd: Question on GATE source geometry

[Matthew Strugari]

Hi David,

Thank you for the information. I ended up using the GPS method with forbidden regions to define my complex source. I defined the source according to the largest dimensions then used the Forbid command to clip the regions overlapping with my phantom. Thus, I was able to confine the activity within a specific volume.

Cheers,
Matthew

________________________________
From: Gate-users <gate-users-bounces at lists.opengatecollaboration.org> on behalf of David Sarrut <David.Sarrut at creatis.insa-lyon.fr>
Sent: July 3, 2019 12:20 AM
To: gate-users
Subject: [Gate-users] Fwd: Question on GATE source geometry


(I forward this because it can be of interest for others users)

---------- Forwarded message ---------
From: David Sarrut <David.Sarrut at creatis.insa-lyon.fr<mailto:David.Sarrut at creatis.insa-lyon.fr>>
Date: Wed, Jul 3, 2019 at 8:20 AM
Subject: Re: Question on GATE source geometry
To: Matthew Strugari <matthew.strugari at dal.ca<mailto:matthew.strugari at dal.ca>>

Hi Matthew,

there are two ways to define source shapes : 1) GPS, 2) voxelized source. Both work but have some interests and some flaws.

1) GPS (https://opengate.readthedocs.io/en/latest/source_and_particle_management.html?highlight=gps)
Only few simple shapes may be defined: Sphere, Ellipsoid, Cylinder, or Para. Warning: the doc is particularly misleading here (code have changed a lot in the past while changes were not all reflected in the docs). Best is to check with https://github.com/OpenGATE/Gate/blob/develop/source/physics/src/GateSingleParticleSourceMessenger.cc

2) for more complex shapes, use voxelized source (https://opengate.readthedocs.io/en/latest/voxelized_source_and_phantom.html#voxelized-sources)
You create an image, with pixel values representing the intensity. I recommend to ensure that the sum of pixel values is equal to 1 (normalization), such as is it then easy to specify the total activity. This vox source is a "virtual" volume you can superposed it with any other real shape in the simulation. Example : TRT in https://davidsarrut.pages.in2p3.fr/gate-exercices-site/docs/exercice5/ with the macros https://gitlab.in2p3.fr/davidsarrut/gate-exercices/tree/master/internal-rt/mac (see source-gps and source-vox).

If needed, you can always use several sources in the same simulation.

We plan to rewrite all documentation in the following months ...

have fun !
David


On Tue, Jul 2, 2019 at 10:15 PM Matthew Strugari <matthew.strugari at dal.ca<mailto:matthew.strugari at dal.ca>> wrote:
Hi David,

Thank you for the information at the GATE workshop in Montreal, I found it to be very useful!

I have a question regarding complex shapes when defining the shape of the source in GATE. I have modelled an Eppendorf tube to contain 4 ul of saline as defined by a semi-sphere attached to a truncated cone. Ideally, I would like to specify this volume to contain Tc-99m as the source. Unfortunately, it appears that I do not have access to these same shapes when defining the source. Is it possible to define an object geometry as the source? Or is there someway that I could define the source to occupy the exact same volume as the geometry in which it is contained? I can't seem to figure out a trick to define a semi-sphere and truncated cone as the source.

Cheers,

Matthew


--

Matthew Strugari

Biomedical Translational Imaging Centre - BIOTIC,
5890 University Ave,
Halifax, NS, B3K 6R8


--
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
_________________________________
 "2 + 2 = 5,  for extremely large values of 2"
_________________________________


--
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
_________________________________
 "2 + 2 = 5,  for extremely large values of 2"
_________________________________
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