[Gate-users] Voxelized source

[Simon Stute]

Hi,

Sorry, I understood the inverse from the previous mail. So you see a uniform
projection, without point source. Did you try to set 3x3 pixels with higher
activity (I mean like a larger point source) ?
GATE print out the total activity concentration read into a voxelized source
: was it the expected one, following what you set in your voxelized
description ?

And to clarify other questions : you can use an analytical phantom with a
voxelized source, there is no problem. Also you can have voxels set to 0 in
your voxelized activity map, there is no pb.

Cheers,
Simon

On Thu, Feb 17, 2011 at 1:17 AM, Ismet Isnaini <ismeth74 at yahoo.com> wrote:

>
> Hi, Thanks for the reply..
>
> yes, I have tried different kind of ratio...
> 1Kbq point source with background of 1Bq, but the result is the same.
> ( I also read in the documentation, that the background shouldNOT be zero,
> is
> that right?)
>
> What I mean is I could not see the point source, not the background.
> All the background seems to have high activity.. the image / sinogram is
> just an
> uniform square
>
>
>
> I am using an ASCII file for the input file, with a linear translator of
> 1Bq per
> voxel as the scale.
>
> Could you please explain the effect of total activity in the Voxelized
> input
> file in relation to the activity of individual voxel ???
>
> regards
>
>
>
>
>
>
> ________________________________
> From: Simon Stute <gate.stute at gmail.com>
> To: Ismet Isnaini <ismeth74 at yahoo.com>
> Cc: GATE mailist <gate-users at lists.opengatecollaboration.org>
> Sent: Thu, February 17, 2011 1:56:46 AM
> Subject: Re: [Gate-users] (no subject)
>
> Hi Ismet,
>
> You set a point/background ratio of 10000 ! it is probably the reason why
> you do
> not see the background in your projection.
> Did you try to set a background activity of 1kBq, so that you get a ratio
> of 10
> ?
>
> Cheers,
> Simon
>
>
> On Wed, Feb 16, 2011 at 3:38 PM, Ismet Isnaini <ismeth74 at yahoo.com> wrote:
>
> dear everyone...
> >
> >I have been running a simulation using a voxelized source (a simple point
> source
> >off the centre) 100x100 voxel of 1 slice.
> >
> >
> >But, instead of using a voxelized phantom, I am using a a cylindrical
> phantom
> >and placed the voxelized source inside this phantom. Is this OK ?
> >
> >The result shows as if it does not recognized the low region of the source
> (The
> >hot area was around 10KBq, and the rest is 0 or 1 Bq, and simulation time
> varies
> >from 100-500 sec). The sinogram / image produced is a square of 100x100
> voxel
> of
> >not uniform  activity..
> >
> >
> >Can anybody suggest, what was wrong with it ?
> >
> >regards
> >
> >
> >Ismet
> >
> >
> >
> >
> >_______________________________________________
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> >Gate-users at lists.opengatecollaboration.org
> >http://lists.opengatecollaboration.org/mailman/listinfo/gate-users
> >
>
>
>
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