I think that stating CT scans have a dose of 150 times as much as an xray has means almost nothing to anybody who is in the target audience and can be considered a harmful statement. It is analogous to stating that with a 5 gig data cap you shoul download a plain text version of book instead of a pdf version, because that is 150 times bigger (nevermind the fact that you are losing images and readability enhancing features such as formatting)