Re: MDL and Dose Effects -Reply

[Todd Jackson <TJJ@nrc.gov>]

I'll throw in my comment that use of all measurement data, including negative values, is
not a new concept.  There was a HP Society standard on environmental monitoring
data published about 10-12 yrs ago that discussed the merits of including positive and
negative values in all statistical calculations of environmental dose rates.  For environmental
monitoring, it is my experience that the practice has become pretty standard over the years,
after the initial difficulties some had of rationalizing how one could ever get a negative
measurement.  
It sure seems reasonable to apply the same approach to a population of dose measurements
to avoid adding a bias to the high side.

Todd Jackson CHP
NRC Region I
tjj@nrc.gov
My personal opinion only, not reviewed by anybody else, etc.
>>>>>>>>>>>>>>>

Supervisor, Radiation Dosimetry & Records
User ID-RUH; Mail Stop-4147;  Ext. 6-1973
It is not fair to report all positive doses unless all negative doses are also reported. We
conducted a study here at the INEL of the raw data over two years of TLD results (over
180,000 TLD readings) to refine our minimum reporting level of 15 mrem. We discovered (?)
that the most accurate results were obtained if the net value is used, positive or negative, with
no minimum/threshold considered. In keeping with the
"theory of large numbers", this gives the best result, particularly for exposures near
background.

>
>Kim McMahan, CHP
>Office of Radiation Protection                             Sola fide ...
>Oak Ridge National Laboratory                            Sola gratia ...
>P.O. Box 2008   Oak Ridge, TN  37831-6290             Sola scriptura ...
>Ph:  (423) 576-1566                                  Soli Deo gloria .
>e-mail: mcmahankl@ornl.gov
>

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