[Gate-users] Defining a radioactive source

[Maikol Salas Ramirez]

Hi Christopher

I am using GATE 8.1, and yes, this is the Ion source configuration and add*
/gate/physics/addProcess RadioactiveDecay*
*BUT:*
I used to use a spectra definition to create the source, and I used the
spectra form the ICRP 107
https://journals.sagepub.com/doi/suppl/10.1177/ANIB_38_3

In the last weeks I have been testing the Ion source definition and
compared with the spectra definition, there are three things:
1- Spectra definition is faster that Ion definition.
2- Spectra definition showed a better agreement with previous studies:
http://iopscience.iop.org/article/10.1088/0031-9155/57/2/517/meta
https://www.ncbi.nlm.nih.gov/pubmed/23927347
3- Spectra definition required to multiply for the total emission
probabilities of the radionuclide, there is an example in the GATE example
folder.

I recomend you to compare your source with other simulation for example:
http://www.medphys.it/down_svoxel.htm
And OLINDA sphere model if you have access to olinda.

An a last thing, if you use the dose actor, there is something pretty weird
that I don´t know the reason, I already dive in the GATE code but I did not
find the source, but to have the right S-value it is necessary to normalize
to 1E9 particles or simulate 1E9 particles.

If you start to work on this, it would be nice to know your results. In mi
case I am simulating a Lu-177 source in a 1mm3 voxel and in the first to
voxel the error with the Ion definition is below 3% but after that all the
values are -20% or around comparing my data with:
https://www.ncbi.nlm.nih.gov/pubmed/23927347
And using spectra definition and emOpt3 I have these values in the voxel
kernel
Position     Error%
0mm          1.048
1mm          -0.856
2mm          -10.755
3mm          2.045
4mm          2.978
5mm          4.137
6mm          2.759
...

Best regards
Maikol


El vie., 16 nov. 2018 a las 16:34, Christopher Watanabe (<
chris.r.watanabe at gmail.com>) escribió:

> Hello fellow GATE users,
>
> I am trying to simulate a Rhenium 188 source, with a half life of 17 h,
> two modes of beta decay @ 2120keV (71.1%) and 1956 (25.6%). There is also a
> corresponding gamma decay of 155keV (15%).
>
> My question is: how do I simulate this? I've found many different answers
> in the forums, including defining it as an ion as follows:
>
> [image: image.png]
>
> However, running this in a simulation yielded nothing in the dose
> distribution, so I have a feeling it's not emitting as I expect.
>
> I've also found in the forums that one must explicitly add
> RadioactiveDecay to the physics processes. This I have done, but I wonder
> if this is necessary in GATE V_8.0. Otherwise, I am also running
> geant4.10.3.1.
>
> Much appreciated! Please let me know if there are any questions I can
> answer.
>
>
> _______________________________________________
> Gate-users mailing list
> Gate-users at lists.opengatecollaboration.org
> http://lists.opengatecollaboration.org/mailman/listinfo/gate-users
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