I can't help with the radiation part of your question but if you need the name of a Boston area dentist who did a great job for me with removable dentures (he does permanent implants too), let me know.
I was told by Dana Farber not to do implants due to the lower jaw/gum bone loss and the need to be able to inspect the gums. My regular dentist at first said he could help but was thrown completely off by my visibly altered jaw/gum, and flunked.

I located a dentist who was highly experienced with dentures and who worked closely with the dental lab to build a denture that really works well for me. He anticipated that they needed more information than a standard impression of my mouth so he also sent them pictures to help them understand. He anticipated another potential problem that would have made the denture work poorly and engineered a correction that solves it. If you need the contact information, let me know.