From:
http://cf.alpa.org/internet/alp/2000/janinflight.htm
"At the present stage of the solar cycle, the galactic dose ranges from 0.023 to 0.80 millisievert per 100 block hours. For example, based on 0.60 mSv per 100 block hours (the mean for a flight between New York City and Athens, Greece), a pilot flying 700 block hours per year would receive an annual occupational exposure of 4.2 mSv. In contrast, a pilot flying 700 block hours on a Chicago-to-San Francisco route (0.41 mSv/100 block hours) would receive an annual dose of approximately 2.8 mSv.
Typically, cosmic radiation exposure for airline pilots in North America ranges from 3 to 5 millisieverts annually. These values are considerably lower than the occupational limit of 20 millisieverts per year (5-year average) that the International Commission on Radiological Protection (ICRP) recommends for a nonpregnant adult."
So, sounds like trash to me...