Radiation doses while flying gliders

I know a few airline pilots and none of them have died of cancer yet,
but with all the news about airport scanners and the comments that the
radiation they put out is the same amount as a few minutes of
radiation while at cruise has me thinking.

Out here in Utah we often spend the day (4-5 hours) cruising between
14,000 and 18,000 ft. I'm not complaining at all but it has me
wondering what kind of radiation we are enjoying. If the aluminum of
an airliner isn't blocking the radiation then my guess is the canopy
of a glider isn't doing much either. I'm not talking about sunburns
but good old fashioned cancer causing energy. It would be interesting
to see if there have ever been studies done to see if airline pilots
or flight attendants get cancer at a higher rate than the general
public...Thanks in advance if anyone has anything to offer on this
subject.

Maybe there is a market for lead bucket hats for glider pilots...

Take care and fly safe,
Bruno - B4