[Gate-users] Strange Dose Profiles

[Christopher Watanabe]

Hello all,

I've been experimenting with dose actors as a means to find a dose kernel
for brachytherapy applications. The simulations run a pure gamma and beta
emitter, separately, embedded at the center of a sphere of various
materials. The strange part is, using the same format (i.e. size volume,
size actor, resolution), I get the following central dose profiles (think
the dose line through the center of the spherical volume) for a pure gamma
(tc99m) and pure beta (P32) emmiter, respectively:

[image: tc99m_centerLines.png]
[image: P32_Centerlines.png]
Note the following:

   - I'm measuring dose for the beta emmitter embedded in a spherical
   vacuum. This should be zero, but alas.
   - The vacuum dose is actually higher than dose in other, denser
   materials...
   - In gamma doses, I would expect the total dose to be the same for each
   material, as all of the gamma radiation should be absorbed by the edge of
   the sphere, but this doesn't seem to be the case.

Having said that, has anyone else experienced this problem?

Best,

Christopher
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