Question on low-dose rad effects

["Jerry Cohen" <jjcohen@prodigy.net>]

Dear Radsafers,
     Perhaps someone could enlighten me on something that has puzzled me for
a long time. Why is the degree of harm, detriment, etc. from low-level
radiation  expressed in terms of rad, rem, sieverts, etc. which are
functions of absorbed energy per unit mass (i.e. ergs/gm)?
 Isn't the probability of a mutation, or other adverse effect a direct
function of the total number of ionizing events occuring in the vicinity of
suseptible DNA molecules and isn't that ,in turn, a function only of total
absorbed energy?
     For example, consider two individuals of the same age, sex, and general
state of health with the only difference between the two being that one
weighs twice as much as the other.  Given that both recieve a radiation dose
of say 1.0 rem, have they both experienced an equal degree of harm? Due to
his/her larger mass, the heavier individual gets twice as many ionizing
events occuring near twice as many DNA molecules any one of which might
result in an adverse mutation.  Why doesn't the individual with twice the
mass, get twice the risk???     Jerry Cohen
jjcohen@prodigy.net



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