Good morning back. CT simulation is no big deal but important for your future radiation. As you probably know, radiation is important to get any stray cells.

I did not have radiation for my breast - I was Stage 4 & at least at the time - chemo & radiation was ruled out. I did have radiation for my brain tumor. Typically breast radiation is more often but shorter duration ( I did only 5x but 20 min each time).
My understanding is that there are some great things that can help with breast radiation - staying hydrated, certain creams, don’t irritate skin where it is being done, etc. They will tell you but check this forum. I can speak to planning & energy. I was fine. I scheduled radiation app’ts when it was good for me. I used the time before I started to rebound my health from surgery. I went in to it taking my vitamins, hydrated & being active already. Some say exhaustion comes after. Maybe but I had things planned & just kept moving. Asking questions like you are & thinking ahead is more than half the battle. Always took work, food, drinks, IPad etc in case things went late - they usually don’t but you never know. And wear comfy clothing!!