Re: radiation and brain

["Gibbs, S Julian" <s.julian.gibbs@vanderbilt.edu>]

Known radiation effects on the central nervous system are:
1.  Interference with growth and development from exposure 
in utero.  Japanese a-bomb survivors exposed before birth 
show decreased mental function, lower IQ, microcephaly 
(small head) and short stature. Maximum sensitivity 8-15 
weeks post coitus.
2.  Brain tumors years to decades post exposure.  First 
seen in excess incidence in children whose scalps were 
irradiated for tinea capitis (ringworm of the scalp) when 
they emigrated to the new Israel in late 40s.
3.  Cataract, following large doses.  Threshold dose about 
1 Sv acute exposure, greater with protracted exposure.

A good readable reference is E.J. Hall, Radiobiology for 
the Radiologist, ed 4, Lippincott 1994.

***********************************************************
S. Julian Gibbs, DDS, PhD               Voice: 615-322-3190
Professor of Radiology                    FAX: 615-322-3764 
Dept. of Radiology & Radiological Sciences
Vanderbilt University Medical Center
Nashville TN 37232-2670        Email:j.gibbs@vanderbilt.edu
***********************************************************
Tell me and I forget; teach me and I remember; involve me
and I learn.
                       --Chinese proverb

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