RE: La Hague1

[stabin@esper.com (Mike Stabin)]

>> I always thought that dose is energy per unit mass and that a rem from
>> external dose to a baby is the same as a rem external dose to an adult. 
>> Is that not so?  Maybe something got lost in translation.  I cannot
>> believe that the National Research Council would not have the correct
>> concept.  Comments?  Al Tschaeche xat@inel.gov (for four more days)
>
>Exact for external irradiation. For internal exposure the dosimetric
factors vary with age. Maybe that creates a confusion.
>
>Best regards,
>Cristian Nicolau

Well, there are two effects going on here that need to be separated out.
First, for internal dose, given a 1 Bq intake by an infant, her organs will
receive a higher dose (specifically absorbed dose, equivalent dose, etc.)
than an adult, assuming the same kinetics, because of the smaller organs.
Then, there also may be increased sensitivity to the dose (risk of effect
per unit dose) due to various age dependent effects.  These two ideas seem
to be somewhat overlapping in some of the messages on this thread.  The
second effect would be observed for both internal and external irradiation,
the first only from internal.  Kim McMahan pointed out some of the
differences that one might expect in the first effect for external irradiation.

Mike Stabin
Oak Ridge, TN