If your DCIS is low grade and you are an older patient, you may want to go to http://www.medpagetoday.com and read some of the peer-reviewed article on radiation findings.
Yesterday, after I agreed to radiation, they gave me a gown and took me to the treatment room. I saw a shiny black, low bench, definitely suitable for an upscale bus stop. They settled me on it with a fresh blanket, and positioned my arms above my shoulders; my tendinitis was not happy about this. Overhead was a lighted mural of branches and colored leaves.
As my girlfriend predicted, there was a strange, lumpy pad under my upper torso. This takes a specific mold of where my shoulders, torso, and arms will be for every treatment.
I mentioned my sinus problems, and they smilingly said, If you have to cough, cough upward. They told me if the cough moved me too much, the machine would stop.
Then the tattoos--more road signs for the radiation. Just three tiny needle jabs with some sort of permanent ink. This keeps the marks from coming off in the shower.
At some points, the bench rolled me back with my breast area under a metal arch. Apparently this is where the radiation comes from. It is perhaps less than a foot thick, like half a big, skinny donut, so I was not really enclosed. Note to self: not claustrophobic.
The whole session was comfortable and non-scary, and the staff were kind, happy, pleasant.
After I got home, I found a paper in my folder saying that the first visit Monday would be a half hour, and if I wasn't comfortable in the position, I should take a Tylenol an hour ahead.