Thank you Techman, for your very useful contribution: very helpful to "bully off" the subject with management on regulatory grounds
i found this site
here to do your own calculations on a date/departure-arrival airports/time of day etc...
and to me it looks far from marginal year on year, something like 3-5 mSv/yr depending on altitude/lattitude when a total of 100mSv equals to generalised cancer...
or to be more accurate, after 25-30years on jets, you're 100% more prone to cancers than the average non-flying person.
scary huh?
well, airliner pilots' life is also made of this, short lifespan...but what a life!!
happy flights