1D gamma analysis issues

I have been using pymedphys.gamma to compare dose profiles. I have read the documentation, but I am confused about the effects of changing the variable interp_fraction. I would have expected the gamma results to converge for increasing interp_fraction above some threshold, but that isn’t what I’m seeing. I have attached images of 3 example cases for 0.5%, 0.5 mm criteria with interp_fraction = 50, 500 and 5000. The gamma values seem to be getting unreasonably low as interp_fraction increases. I’m not sure what is going on!

Hi @pakoliver,

That is concerning. Would you be able to provide a minimal reproducible example? See the following for what I am asking for specifically:


Well, this is embarrassing! When I was making my MRE, I realized I didn’t convert something to the correct units. So the interp_fraction was having a really big impact on my results. It’s all good now I think. Sorry about the confusion. Thanks for your time!

That’s all good!

Don’t be sorry at all :slight_smile:. A huge, huge benefit of open source, and the PyMedPhys community is iron sharpens iron. It is my hope that when we work together, we all get better :slight_smile:.

Welcome to the PyMedPhys community :slight_smile:, and, if you have some success with Gamma, please consider seeing if you can help others solve the problems you had by maybe providing an example to share?

I would be happy to try to help others, but no guarantees since I am still very new to PyMedPhys! :slight_smile:

All good, that gives you a useful perspective. The very issues you’re having are likely in the blind spot of those who are more familiar, and if you are struggling with something, and then solve it, there will likely be many others in the same boat.