Re: LNT theories

[Stanley Fitch <stanley_fitch@nmenv.state.nm.us>]

Best regards to Dr. Cohen and Dr. Raabe.  More food for thought
regarding the argument of LNT vs. negative slope for tissue damage
relative to low dose.  Although the following comments are relatively
obvious, I feel they are worth repeating.

For typical ambient radon concentrations, the mechanisms for cellular
repair and regeneration are more than adequate.  This in spite of the
fact that for the general population radon is the leading cause of
cancer from radiological sources.  As mentioned by Dr. Raabe there are
aggravating factors, most notably aerosols which can greatly compound
the effectiveness of radon and its progeny.  Even so, this does not
detract from the marvelous ability of tissue to repair itself via
molecular kinetics.  However these kinetics are less successful in the
scenario of chronic doses somewhat higher than those typical of ambient
radon.

A few years ago in the uranium oxide milling industry, our greatest
concern was to prevent the inhalation and ingestion of dusts to reduce
the incidence of cancer.  However, medical research of cohorts from the
industry has revealed a striking incidence of non-cancerous diseases.
Most notably pulmonary fibrosis.  Under ideal conditions, inhaled
particles of dust of relatively high activity from radon progeny
sufficiently irradiate cellular locales to initiate scarring.  A leap
past cancer directly to scarred tissue masses.  Arguments for either
hormesis or LNT matter little in this situation where proper repair by
molecular kinetics is incapable of succeeding.

Stan Fitch
stanley_fitch@nmenv.state.nm.us


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