[gate-users] Re: gate-users Digest, Vol 16, Issue 7

[steven staelens]

>
> Message: 3
> Date: Sat, 9 Jul 2005 13:26:07 +0100
> From: "Susana Silva" <susana.silva at fc.ul.pt>
> Subject: [gate-users] Doubts about voxelised phantoms
> To: <gate-users at lphe1pet1.epfl.ch>
> Message-ID: <DB92A097E63F06499D49DF3501689662520681 at exchange01.ul.pt>
> Content-Type: text/plain;       charset="Windows-1252"
>
> Hi everybody!
>
> I have some questions about voxelised phantoms. I'm trying to use a voxelised phantom in GATE. Some of you may know it - the MOBY phantom. So, to use it in GATE I have to update the materials database, and create a macro file where the materials are defined to the respective voxels. To understand this I use the Hoffman phantom. My question is: to made the macro file with the materials and the correspondent voxels how can i reference each voxel? In another words, how can i reference that voxel (x=145, y=34, z=45) is made of material "abc"? The only example that i have (in the user guide, the brain) is the one referencing voxels 1 to 25 made of material a, voxels 26 to 50 is of material b, and so on. But this only references one dimension, and i have a three dimension phantom.
> I'm having a hard time to figue out how can i say to GATE that my voxels (well, ALL voxels do) have 3 dimensions and the position of each voxel can only be referenced with the reference to the position in the 3D space or, at least, 2D space if i work with slices of the phantom.
>

Hi Susana,

The brain example you are refering to is also 3D.  The differentiation is done using the z-value of your example (==gray value of the image).  So a segmented image (0-25,26-50,...) of which the gray values are translated to material.

hope this helps,

regards,

Steven

Steven Staelens, Ph.D.
Ghent University
ELIS Department
Proeftuinstraat 86
B-9000 Gent
tel.  +32 9 264 66 28
fax. +32 9 264 66 18
Steven.Staelens at ugent.be



>
> I hope you understand my doubts in here, and can help me.
> Thanks in advance.
>
> Cheers,
>
> Susana Silva
>
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> End of gate-users Digest, Vol 16, Issue 7
> *****************************************