[Gate-users] Defining phantom and activity range files in Gate

[Thibault Mauxion]

Hello, 


Le 25 janv. 2013 à 06:05, Karr Aguwa a écrit :

> Hello Gate Users, 
> 
> I am trying to define a voxelized source and phantom in Gate, and I am stuck at defining the range files. I have used NCAT to generate my phantom, then I used a small matlab script to convert to the int16 format as specified. 
> 
> 1st) Question
> How do you properly define this range file? This range file defines the ranges of the different organs that's in the phantom. So where can I get the information to define this range file? The user manual doesn't explain where those values from or where to find it. I have been messing round with th example that's in the example folder but I still don't understand where the values are coming from. Please help!
> 

Indeed, you can find an example of how to use range file in the "Voxelized_Phantom_Source" example available in the example folder of gate sources. You 'll also find another example in the preclinical example available on GATE website in the example section. Basically: 
- the first line contains only the total number of lines
- the other lines define the range "inferior bin" "superior bin" and activity value

The activity value is relative, since GATE gives a result per particle. Therefore, if you put
2
1 8 0 
9 9 1 

your source will be uniformly distributed all voxels labeled "9". 

About how you define the labeled, it's totally up to you or to your phantom. 

If your phantom is labeled as: 

1: skin
2: bladder
3:liver
...

and you want to localize the source in the bladder, the you should define the line "2 2 1" and others to 0.


> 2nd) Question
> The same from above, where does the values come from for the activity range file as well? I understand what it's doing, but where/how do I figure out the values.
Again, if i get it correctly, your values totally depend on the labeled voxels of your phantom. 

> I know you specify a range and the activity in the file. Does the activity you put in there over writes the activity you set in the source? like this /gate/source/voxel/setActivity 1 Ci Help please!!
> 
> I usually don't use this command line with the range method. 


> Thanks. 
> 
> -- 
> Karr
> _______



Hope this helps a bit

Thibault  
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