Lost/Damaged Dose Estimates Compilation

["Michel, Rene" <rmichel@iastate.edu>]

Dear Radsafers,

For those interested in the topic "Lost/Damaged Dose Estimates", I list all
the comments and suggestions I received on this topic.

Thanks to all radsafers that sent me their comments on the subject.

René

René Michel
Iowa State University
rmichel@iastate.edu

Contribution #1

We use a 4th Dimension DB for Mac for Dose results for the monitoring we do
on campus.  When a badge is lost/marked absent during the electronic import
of dose results the program calculates the average dose for the person
taking the last 12 months of information.  If there are only a few months of
previous results we pull the documentation and do a more intense estimate of
actual exposure.  If the real Dose comes in later it writes over the
Administrative Dose Assignment we calculated.
Joe Kane
University of Pennsylvania
email:  jkane@ehrs.upenn.edu <mailto:jkane@ehrs.upenn.edu> 

Contribution #2

Factors used in deriving a dose estimate are pretty universal, i.e.,
historical data, coworkers' exposures, field data, secondary dosimeter, etc.
However, just a philosophical note here, the Navy tends to 'frown' on taking
averages.  So in our instructions we say that the dose estimate is NOT based
on the average, but on the BEST estimate.  For example, if the worker's
historical exposure data performing generally the same type of work are 2,
10, & 35 mrem, are you to take the average (16 mrem), the most conservative
(35 mrem), or the best approach?
Ray Fong (Navy)

Contribution #3

These are my recommendations and are in use at ICN. Hope this helps:
1.	No matter what methodology is used, it is incumbent on the facility
to investigate what the potential dose to the individual should have been.
There is no guarantee that what was received in the past is indicative of
what the individual is currently receiving.  The work scope of the
individual, interviews with the individual should ensue to determine any
abnormality that would have resulted in a higher dose than previously
received.  
2.	For monthly dosimetry, the estimated dose should be based on the
average of a continuous 12 month period, prior to the dose in question.
However, when there is significant variability within the doses received
previously, I think the conservative approach would be to take the average
based on the most consistent doses (at the higher level), as long as the
period in review is at minimum, 4 of the months.  
3.	For quarterly dosimetry, the previous 4 quarters should be reviewed,
and, the same caution needs to be considered, that being variability within
the previous 4 quarters.  
4.	If the facility is a new client, and there is no previous history
with the processsor, I recommend that for monthly dosimetry, we take 1/12 of
the of the previous years exposure, as reported by the previous processor.
For quarterly, ¼ of the previous years exposure, as reported by the previous
processor.  
5.	If there is no previous history, I highly recommend that there needs
to be a minimum of 4 dose reports prior to automatically assuming an
estimated dose for an individual.  
5.	The Occupational Exposure Report will designate that there has been
an estimated dose provided to the individual, either current year and/or
lifetime.  
6.	There needs to be an open communication between the processor and
the facility to address specific issues with an estimated dose.  


-----------------------
Sandy Perle
ICN Dosimetry Division
sperle@icnpharm.com <mailto:sperle@icnpharm.com>  or sandyfl@earthlink.net
<mailto:sandyfl@earthlink.net> 

Contribution #4

I another requirement for personnel lost dosimetry would be a general
interview of the workers and a survey of the work area or equipment.  The
Co-workers dose may be off by a factor of 2 to 4 etc.,  depending how close
each worker was to the source and time spent. One to two feet can make a
great deal of difference between the two workers, which you already know.  
Best Regards,

Jim Kost
jkost@mgpi.com <mailto:jkost@mgpi.com> 

Contribution #5

I just had a case you might be interested in last week.  Our administrative
limit is 500 mrem/yr.  98% of our people get <25 mrem/yr.  Last week we were
notified by our TLD processor (ICN) that one of our quarterly TLDs indicated
976 mrem.  Upon investigation, we found a WWII compass in his truck where he
laid his security badge and TLD each evening.  The compass had a radium dial
and read in excess of 5 mrem/hr on the surface.  We assigned the man the
highest dose any of his coworkers received for the same quarter.  This is
the second radium compass event I've had to deal with in 5 years.
Another man in our maintenance facility came up with several rem (>5) whole
body one quarter a few years ago.  The chip readings and the glow curves
indicated the TLD probably was exposed to radiation, but not the kind we had
onsite: high-energy particles and soft photons; all we have is UF6 and some
Tc-99 contamination.  People in this shop do not normally receive a
quantifiable dose in a quarter.  Much, much investigation went into this
one.  We were able to build a case acceptable to the DOE and the NRC that
the exposure did not come from our site, and therefore was not occupational.
Had we not been able to make the case, we would have been cited with a
violation of the annual dose limits.  We never did find out how or to what
the TLD was exposed but we did uncover a few other interesting facts: the
man was on psychiatric leave all but 14 days that quarter.  One of the few
days he was at work he accused HP of not reporting TLD results to him
honestly.  He went on to say that he "knew" how to put something on the
devices and he was going to do it just to see what we would do.  This was
just a few months after the OK City bombing.  Our security department saw to
it that he "retired" soon thereafter.  It really irks me that a nutcase was
able to do something to a TLD that I (nor the TLD processing center at Oak
Ridge) never could discover.  Always be prepared to investigate anomalies.