I've been in Radiology almost 15 years at this point. Although we have all been taught proper safety procedures I've held patients for XRAY exams, walked into CT scan rooms while the scanner was on, and stood too close while making exposures. With this being said I am horribly uncomfortable with flying! I know radiation is pouring into my being for long periods of time and all I can do it sit there, drink nasty wine, and eat nuts.
I figured I was being a sissy so I sucked it up. When my pregnant wife flew with me to Florida recently I had to know what the exposure was. After some research I learned there was more to be concerned about than I thought! But not for us.
A study published recently in JAMA Dermatology (link at the bottom) suggests the aviation crew on the plane are at significantly higher risk of getting Melanoma; twice as likely in fact. If you look at the amount of radiation they receive annually you may see why. Per the study aviation workers receive about 3.07 millisievert annually. To put that in perspective the typical nuclear power plant worker gets around 1.87 and XRay Techs get around 1.2. A standard CT of the chest yields about 7 millisievert.
A flight from New York to LA is about .04 millisieverts and a chest XRay is 0.1 so I wasn't too concerned with my piddly flight to Florida anymore.
In my research I did learn that Astronauts get some serious exposure. A 9 day trip to the moon would yield over 11 millisieverts. With this in mind, I will keep my pregnant wife away from lunar missions.
Listed below is the JAMA study as well as a cool Radiology site that tells you exposure for various exams.