[Gate-users] Questions on Dose Actors

[Grevillot Loic]

Dear Nada,

It is very hard to understand every user specific test and provide appropriate answer.
Could you try first some Gate radiotherapy examples and use the Gate documentation to get familiar with the dose actor?

Sincerely,
Loïc




-----Original Message-----
From: gate-users-bounces at lists.opengatecollaboration.org [mailto:gate-users-bounces at lists.opengatecollaboration.org] On Behalf Of Nada Fakhoury
Sent: Friday, April 03, 2015 6:50 PM
To: gate-users at lists.opengatecollaboration.org
Subject: [Gate-users] Questions on Dose Actors


Dear Gaters,

I have some questions on how the dose actors actually work.

In the case of a Radiotherapy Simulation, let's assume we have a water phantom of 50x50x50 cm and we attach to it the Dose actor with a resolution of 1 1 500, at the center of the volume. That would mean that the dose is calculated in voxels with a size 500 500 1 mm. So that essentially means that dose is calculated by layers of the entire phantom, am I right?

And in the case of attaching the same actor to calculate a dose profile on the x axis at various depths, if for example it is attached at z=10 cm depth and the voxel size is now 1 500 500 mm, won't the voxel dimensions exceed the volume boarders in the z direction on one side?

I am puzzled by the above, by the fact that when acquiring dose profile in various depths the seem to me perfectly fine, as they do present a dose reduction by depth. But when I think of the voxel size, I am troubled.

Now, for precision's sake I know that I can alter the voxel size and attach the dose actor exactly where I want.

But my current goal is to validate my geometry with dosimetric data.
And the question is whether I can or cannot use the dose actor as stated in the begging. And that is for two reasons. My dosimetry data was taken with an ion chamber, which means that it was taken with a specific voxel size. But if I wish to make a simulation with a much smaller voxel size than the one I've been using so far, that would mean I'd have to use way more primary particles than I already do. But since I am only running GATE on my laptop, I don't have the computational capacity to run with too many particles.

So should dosimetric data be compared with dose calculated with a 1 1
500 resolution , just for the sake of validating a geometry and a source's energy?

Cheers,
Nada
--
Nada Fakhoury
MSc "Medical Physics" Student

_______________________________________________
Gate-users mailing list
Gate-users at lists.opengatecollaboration.org
http://lists.opengatecollaboration.org/mailman/listinfo/gate-users
Disclaimer:
Please notice our E-Mail Disclaimer http://www.medaustron.at/email-disclaimer/