Ring Badges

[Steven Hand <SHAND%UMDACC.bitnet@vmd.cso.uiuc.edu>]

From: shand@umdacc.bitnet

The University of Maryland College Park holds a Broad Scope License for
Byproduct material.  Ninety-nine percent of the isotopes used on the campus
consist of I-125, S-35, P-32, C-14 and H-3.  Of this 99%, roughly 75%
involves P-32 and S-35.  A recent inpsection of the license by the
Agreement State Agency in Maryland raised a question as to the University
Policy regarding the use of ring badges whenever P-32 is utilized by
an individual.  No where is it written in the University regulations or
Radiation Safety Manual that this is mandatory or recommended other than
the fact the proper dosimetry shall be worn.  The state inspector noted
that some facilities use a threshold activity of 1.0 mCi as their control
policy for using ring badges; however, as documented by dosimetry reports
or users on the campu, exposures to the fingers and hands occur when the
amount is well below this level.

Some documentation on this subject may be found in the NCRP reports:
NCRP 32 recommends using dosimetry where an exposure may exceed 10 mrem
for educational uses of isotopes and/or devices.

NCRP 57 recommends the use of dosimetry for the extremities when:
" significant fractions of the applicable MPD might be received."

NCRP 59 states: " the use of monitoring devices on personnel who normally
receive low exposures can reveal developing trends or unusual practices.
The indication of a dose equivalent of 100 mrem for one month may be within
recommended dose equivalent limits, but could well represent unecessary
exposure. "

The kind of exposure stated in NCRP 59 above has been found through the
use of ring badges for laboratory workers at the University and in most
cases the experimental procedure has been corrected and the exposure
reduced to a level that was not measurable by the dosimeter.

The University of Vermont Radiation Safety Manual explicitly states:
" ... wear a ring monitor if your hands could be exposed to radionuclides
which emit beta particles with an energy exceeding 0.5 MeV or gamma with
any energy."

With the new 10 CFR 20 regulations, limits and definitions of ALARA
as well as a no threshold practicing theory of stochastic effects,
etc... WHAT threshold based on activity, energy, frequency, toxicity
level, etc... if any, are Licnecees using to set policy and regulations
regarding the use of ring badges or extremity monitors.

thank you, and apologies if I took to long to ask the question.

steven hand
radiation safety
university of maryland college park
(301)-405-3985
shand*umdacc.bitnet