I've been aware of the CT/radiation issue for some time. When I asked the oncologist (who is the one ordering the scans) about the issue, she really didn't have an answer. Since I can't have MRI's, CT scans are really the only way to know whether cc is being held at bay or not. I figured this out for myself. Clearly she knew about the radiation risks, it is just that cc posed a greater risk. The good news is that there is development being done to produce quality imaging with less patient exposure to radiation.
Hospitals/Doctors Link, Our Experiences: http://www.cholangiocarcinoma.org/punbb/viewtopic.php?id=3126 See page 4 of thread for Dr. Tomoaki Kato info.
Major USA Cancer Centers: http://www.cholangiocarcinoma.org/majorcancercenters.htm