Sorry
mphysflier but it is rather more complicated than that. The ED is a simple summation of each tissue in the body. It takes no account of the relative
absorbtion of certain tissues such as bone which is 9 times higher, nor does it correct for age related risk. We use the ED merely as a measure of total exposure when using continuous X ray screening.
Risk is somewthat different. It has been estimated that CT scanning in the US alone will cause 29,000 extra cancers per year of use. Whereas the risk to the individual is low and normally offset by benefit, the risk, for example of an abdominal CT is greater than the risk of detecting bowel cancer in an unsymptomatic person up to 40.
The suggestion that diagnostic radiology is no more dangerous then flying is I regret far from the truth, so I wouldnt give up the day job just yet.