RE: Does Size Matter?

["Sorensen, Scott" <ssorensen@doeal.gov>]

Does size matter?  Radiation dose from whole-body irradiation, expressed
as Sv (J/Kg) or Rem (ergs/g), basically is an average energy-deposition
concentration (on a macro scale).  As such, the more mass a person has,
the more energy that is deposited.  The more energy deposition, the
greater the number of free radicals (i.e., reactive species) generated.
The more free radicals floating around, the greater the probability for
adverse interactions with cell nuclei,  thereby initiating
carcinogenesis.  This seems to indicate that, for stochastic processes,
size does matter.

Another way of looking at this question is considering target areas.
Larger, non-obese people tend to have physically larger and more massive
organs than smaller individuals.  Therefore, the number of radiation
interactions within sensitive organs should be higher for larger people,
given the same energy fluence.  Once again, it seems that size dose
matter when looking at stochastic radiation effects.

This is probably too simplistic...?    Any additional thoughts?

-Scott Sorensen
ssorensen@doeal.gov
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