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RE: EPDs for personnel monitoring and surveys
Tom Goff asked if Sandy Perle and I are out there. Of course, Sandy's there!! Can you miss him?
And yes, Tom, I'm lurking out here. I thought it was a great question about EPDs and radiographers. Many people know my position on EPDs: that I do NOT support them for primary dosimetry, but that they are incredible tools for radiological safety and ALARA. Mr. Dahlskog's comments probably related to the use of these instruments to assist with the rash of radiographer overexposures. He is absolutely correct: with the new EPD dose and DOSE RATE alarms, they should virtually eliminate accidental exposures (as long as they are worn).
I would add another thought:
There have been several cases where the dosimetry results were the only documented evidence that anything may have happened . I can cite three:
Exposure to a soil moisture probe where the film badge areas read:
4400 mR 5500 mR 8900 mR 12100 mR
A radiography exposure where the two TLD elements read 3.5 R and 10.7 R, with the deep element being the highest.
A radiography exposure where the TLD dose was "between 240 R and 510 R", I have to guess that this meant that the two elements read 240 R and 510 R.
I have my opinions on these exposures. I always suggest that the badge readings be recreated first, before any other work begins.
Mike Lantz, CHP
..
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From: Goff, Tom
Sent: Thursday, January 21, 1999 5:49 AM
To: Multiple recipients of list
Subject: EPDs for personnel monitoring and surveys
Mr. Dahlskog:
This is a very interesting subject which would be a great subject for
RADSAFE discussions.
One of the key concerns about using EPDs for personnel dose was that some of
them could be used as survey instruments. Unfortunately, any measurements
obtained, such as looking for hot spots, are recorded as dose to the
individual.
The use of EPDs for personnel dose (as opposed to exposure tracking and
control) was explored at the Atlanta HPS Chapter meeting a few years ago
(1995, I believe). I would suggest that any of the attendees/presenters at
that meeting contribute to this discussion. (Lance, Pearle; are you out
there????)
Tom Goff
Rad Engineering
Rocky Flats ETS
> -----Original Message-----
> From: Dahlskog, Leif [SMTP:Leif.Dahlskog%health.wa.gov.au@inet.rfets.gov]
> Sent: Wednesday, January 20, 1999 7:43 PM
> To: Multiple recipients of list
> Subject: Monitoring in Industrial radiography
>
> To other regulators out there. I have a query concerning the trend in
> personal dosimetry and survey instruments.
>
> In most places I'm aware of, each industrial radiographer and assistant is
> required to wear TLD's (or a film badge) and a personal audible alarm
> (which
> provides an increasing rate of response with increasing dose rates). The
> team must also use an appropriate survey meter which due to design have
> always been hand held instruments.
>
> These days sophisticated and programmable compact electronic dosimeters
> are
> available with various functions such integrated dose, dose rate
> measurements, audible alarms at preset dose or dose rates, data logging.
> They are typically designed to be clipped to the users clothing.
>
> Are there any trends toward the use of these compact devices in industrial
> radiography instead of hand held survey instruments ? Please post your
> comments on any issues to my personal e-mail.
>
> Regards from upside down under :-)
>
> Leif Dahlskog
> Scientific Officer
> Radiation Health Section
> Health Department of Western Australia
>
> leif.dahlskog@health.wa.gov.au
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