I had IDC Stage 1A with clear margins and lymph nodes after a lumpectomy at the Mayo. Lower left quadrant of left breast. Unfortunately, oncotype testing indicated I needed 3 months of chemo, which I just completed. That was more fun than the law allows. 3 weeks of once a day M-F targeted radiation start Monday. As a swimmer, I'm used to taking big breaths that inflate the chest and pull in the gut. As I went through the set-up for radiation, I was told the beam cuts off if my chest deflates from the targeted position and gets too close to the heart. Sounds good to me.