Re: x-rays, IRB, rad-safty, consents, r

[a.zapantis@qut.edu.au (Alex Zapantis)]

>Wasn't thinking of different individuals/masses. Is the total imparted energy
>to a larger individual due to a larger mass at the same rad/rem dose really a
>higher risk? Would not seem obvious.  
>

Should we not base risk estimates on effective dose? (I do!!) And if so,
doesn't effective dose take into account ALL factors, ie organs (or portions
of organs) irradiated, RBE of the radiation (I suppose I should say
radiation weighting factor). Thus is it not correct to state that the risk
accepted by individuals of differing masses who have received the same
equivalent dose to the same portions of the same organs (ie have received
the same effective dose) is identical, even though more energy would have
been imparted to the larger individual? 

When communicating risk to the lay person for small doses, is it not best to
use the simple 500 per million per 10mSv (effective dose) risk factor for
all cancers as stated in ICRP60 and then compare the risk thus calculated to
the risk of dying by more familiar means eg car accident or smoking 20
cigarettes per day?

Given the large uncertainties generally inherent in radiation protection, I
believe that we should not be too concerned with attempting to calculate
doses or risks to 4 significant figures. At risk of being labelled
superficial, I firmly believe that simple is best (wherever possible).







                        Alex Zapantis
                        Radiation Safety Officer                               
                        Queensland University of Technology          
                        Health & Safety Section                             
                        Locked Bag No.2
                        Red Hill Qld 4059
                        AUSTRALIA

                        Ph     : 61 7 864 3566
                        fax     : 61 7 864 3993
                        email  : a.zapantis@qut.edu.au