Mobile Dental X-ray Units

[Gibbs, S Julian]

Some questions for Col. Vandre:

1.  The environmental dose from cosmic radiation at the
altitude of Denver is about twice that at sea level.
However, cosmic radiation at sea level contributes only
some 10% of background, or 0.3 mSv/y.  So moving to denver
would double that to 0.6 mSv/y, increasing total
naturally-occurring background from 3 to 3.3 mSv/y--that is
by 10%, not double. (Data from NCRP) What is the exposure
to the operator from the handheld unit?

2.  What is meant by "daily background radiation dose at
sea level for one exposure of a D-speed film?"

3.  Are you still using D-speed film?  If so, why?

4.  Why is it necessary to use a handheld unit?
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S. Julian Gibbs, DDS, PhD               Voice: 615-322-1477
Professor, Emeritus                       FAX: 615-322-1474
Dept. of Radiology & Radiological Sciences
Vanderbilt University Medical Center
209 Oxford House
Nashville TN 37232-4245        Email:j.gibbs at vanderbilt.edu
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                                       Democracy in America