Command-based scoring and detector geometry

Geometry, Fields and Transportation
1

Hi all,

I’m trying to perform a simulation of a brachytherapy eye plaque. I’m using the program that is shared here: https://github.com/hrsommer/ccb-plaque-simulation.
However, instead of having 35 small detectors, I would prefer to have 80 detector blocks of 0.5 mm in all directions, resulting in 512000 detectors.

I thought using command-based scoring would be the easiest solution to do this and I’ve adapted the code above, to get it working. So far, it seems to work, but it seems that the 1 mm layer of silver in the original geometry is not taken into account with the command-based scoring. I would expect the dose behind this layer of silver to be lower, but this is not the case.

Does this have to do with the fact that the command-based scoring happens in a parallel world? And if yes, how can I get my layer of silver into the parallel world where the scoring is done?

Thanks so much in advance!
Lisa

2

Does this have to do with the fact that the command-based scoring happens in a parallel world?

No, the simulation considers the parallel world and real world together. The problem is elsewhere.

I don’t know much about this setup. What energy is used? 1 mm of silver isn’t much for shielding–maybe it is acting as a buildup layer (increasing the surface dose) instead?

3

Thank you for your reply!

This simulation is based on the decay of 106-Ruthenium, which disintegrates to 106-Rhodium (which in turn disintegrates to 106-Palladium). The latter contributes most to the dose and produces beta particles with a mean energy of 1.43 MeV and a maximum energy of about 3.54 MeV.