My Aunt is a radiologist and I've shadowed her a few times. She works at MD Anderson in Houston, and she actually sees patients quite a bit and assits in surgery, although that is admittedly not the norm for a radiologist. She specializes in breast mammographyand biopsies, so we spent a lot of time looking at films of breast malignancies but also of lungs and whatnot. I watched her assit with a few minor surgical procedures, like biopsies and catheterizations as well. I also listened as she told a woman she had breast cancer.
I've been with her (at work) like 3 or 4 times, and it never fails to be interesting. But again, I think that's a function of where she works too, and the heights she has reached in her career field. She herself has described it as being in a kind of radiologist's "candy shop" because she gets to treat so many different kinds of patients with different kinds of diagnoses.
If you can get in to shadow a radiologist at a hospital like this, it can be a very interesting experience. Clinic radiologists really do spend a lot of time looking at films and rarely see a patient, whereas at the specialty hospitals they do a lot more.