I don’t know. During my consultation pre-radiotherapy I was asked about prescription drugs I was taking. I don’t recall a discussion about antioxidants. This older paper suggest there are mixed views https://www.ncbi.nlm.nih.gov/pubmed/17761641 , but the dose used for cancer treatment is a lot higher than that for DD. I would find await your radiologist feedback, and surely if you’ve just started you will seen them again tomorrow?

This may well be a bit late but may be useful for others.

Clearly Manganese is a different element from Magnesium. Manganese is present in low amounts and is an effective free radical scavenger, hence its antioxidant effect.

There is not clear evidence that taking anti-oxidants prevents or lowers the incidence of cancer
https://www.cancer.gov/about-cancer/caus...ants-fact-sheet

RT will generate free radicals, potentially contributing to the minor associated tissue damage. Free radicals may be a part of the process of stopping the progression of the disease. It is conceivable that anti-oxidants may reduce the efficacy of RT in halting/slowing DD but any impact is unclear.

I would not be taking anti-oxidants during and after RT and as suggested, use urea based moisturising hand cream to minimise impact.

Magnesium is an essential metal iron, present in relatively high amounts in most normal diets, has no antioxidant properties and is unlikely to have any impact on DD progression, RT or cancer treatments.