@big17781
I assume by high dose radiation you are talking about the high dose 5 day (usual) high dose radiation treatment instead of the low dose long term plan of 20-30 days of radiation treatments or even more.

Your medical provider should have given you dietary guidance on what to eat and not eat. I know one thing to avoid is beans and soy. They cause gas in colon which can move your colon around. I pass this on to you as was given a list of foods to avoid and one was soy. I was doing a protein drink one day and did not think anything of it.

When I got to UFHPTI and laid on table (use a low dose xray to line you up) they came in and said see gas in colon and have moved your prostate so far away from program we need to adjust the bed. They asked what I had ate or drank as causing it. I did not know. But when I got home I looked at the protein powder and saw Soy. And my techs said yep that will cause it.

So asked your medical providers what you should eat not eat, drink not drink, as they have your medical history and aware of any other medical concerns. Wish I could help more but my diet restrictions were specifically designed for me.