Re: RADSAFE digest 3384 (extremity dose)

[Dave Derenzo <dave@uic.edu>]

In one of my previous positions I switched users from wrist badges to ring 
badges.  We were processing multi-curie (in the 100's) quantities of Mo-99 
and Tc-99m.  Recorded extremity doses increased sharply.  On our next NRC 
inspection we were soundly criticized for increases in extremity 
dose.  They didn't care to recognize that the real doses didn't change, 
just the location of the dosimeter.  I thought they were being bone-heads, 
they should have been giving us credit for trying to do a better job of 
measuring extremity doses.  I guess that no good deed goes unpunished.  So, 
I agree with the comments below, especially in the light of the recent 
Mallinckrodt problems.

Dave

At 03:15 PM 8/23/00 -0500, you wrote:
> >If individuals are directly handling unshielded sources without remote
>handling,
> >then fingertip badges are needed (assuming significant dose is being
>received*).
>
>Wrist dosimeters offer an operational convenience that is very attractive to
>many programs, but it comes with a significant cost in terms of work
>required. Except in very unusual exposure geometries, the wrist will not be
>the maximally exposed location of the extremity being monitored. Therefore,
>the dose measured at the wrist will have to be adjusted by a factor that has
>been determined experimentally or by calculation. In either case,
>considerable homework and good documentation of the basis for such a factor
>will be necessary if the facility wishes to have any hope of defending the
>assigned doses, should a need arise.
>
>A side note: extremity dosimeters are a constant source of complaints - they
>are uncomfortable and interfere with the wearer's activities, and wrist
>dosimeters are no exception. Do not expect to see user complaints decrease
>if you switch to wrist badges.
>============================
>Bob Flood
>Dosimetry Group Leader
>Stanford Linear Accelerator Center
>bflood@slac.stanford.edu
>
>
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Dave Derenzo, MPH  (dave@uic.edu)
Associate Director for Radiation Safety
Radiation Safety Officer
University of Illinois at Chicago
Radiation Safety Section, MC932
820 S. Wood St., Chicago, IL 60612-7314
Voice:(312)996-7429  Fax:(312)996-8776
URL:  http://www.uic.edu/depts/envh

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information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html