Dear Colleagues: Below is the latest "edition" of what I originally (1989)
called BERT - Background Equivalent Radiation Dose for explaining
radiation to the public. I plan to propose that the Health Physics Society
consider the following motion for transmission to the Surgeon General:
"Resolved that all explanations of radiation to the public be given in
terms of time to acquire the same effective dose from background
radiation." Some HPS chapters may wish to consider this motion at their
next meeting. The NCRP approved this idea in NCRP Report No. 117 1993
(page 51). I plan to ask all radiation related societies to pass similar
resolutions. Your comments and suggestions are requested to
jrcamero@facstaff.wisc.edu
A RADIATION UNIT FOR THE PUBLIC (NOT COPYRIGHTED)
A radiation unit for the public has been proposed by Professor
Emeritus John
Cameron of the University of Wisconsin-Madison based on natural radiation.
The unit is easily understood by the general public and news reporters.
Radiation is measured in time - how many hours, days, weeks, months or
years of natural or background radiation will give you the same effective
dose as the medical exposure. Compare "Your mammogram gave you about 100
mrems of effective dose.: OR "Your mammogram gave you radiation equal to
about four months of natural radiation."
A dental bitewing is equal to about one week of natural radiation;
a chest x-ray to about ten days; and a barium enema x-ray study, to about
one year. Each medical center should measure their own x-ray equipment
since the dose varies from one x-ray unit to another. The average amount of
radiation to the public from diagnostic x-rays each year is equal to about
seven weeks of background.
There is no evidence that natural radiation causes cancer. There is
some evidence that natural radiation might actually reduce cancer. The 7
western states with the most natural radiation have a cancer death rate
about 15% lower than the average for the country. (1) A study of radon
levels in homes Vs. the lung cancer death rate in 1700 counties shows that
the counties with the most radon have the lowest lung cancer death rates.
Counties with more than 5 pCi/l have 40% lower lung cancer death rates than
the counties with radon levels below 0.5 pCi/l.(2) It looks like radon in
the home actually prevents some lung cancers caused by smoking! Smokers may
wish to consider how to increase their home radon level if it is below 5
pCi/l.
(1) JH Fremlin - Power Production - What are the risks? 2nd ed. Adam Hilger
1989 p. 58
(2) Health Physics 1995 68:157-174
Check out ELECTRONIC MEDICAL PHYSICS WORLD - EMPW - which links to AAPM,
IOMP etc.at http://www.medphysics.wisc.edu/~empw and the Bibliography of
books and journals in Medical Physics and related fields at
http://www.medphysics.wisc.edu/~cameron.
John R. Cameron, 2571 Porter Rd., P.O. Box 405, Lone Rock, WI 53556-0405
Phones: 608/583-2160; Fax: 608/583-2269
At the end of September we return to our home at 2678 SW 14th Dr.,
Gainesville, FL 32608 phones : 352/371-9865; Fax 352/371-9866
my e-mail all year is: jrcamero@facstaff.wisc.edu