Yesterday, I had some breathing tests and a high resolution cat scan of my chest done at the Ohio State University Lung Center. I have had about 6 cat scans done of my chest done a a local community hospital. I was asked to lay on my stomach for the most part of the scan. I asked the tech what the difference was and she just said that for females you get a clearer scan when the breasts are out of the way. Think simple I guess...