Re: Use of Portable Radiati

["Mike Bohan" <mike.bohan@yale.edu>]

        Reply to:   RE>>Use of Portable Radiation Monitoring Equipment

Hi Ted and RADSAFERS,

I hope the NRC read your post.  I tried to convince them during our license
renewal that this was the way to go for High Dose Rate (HDR) remote afterloading
brachytherapy facility.  

Our facility has three separate, independent, battery backed, fixed alarms.  The
first is a visual alarm, located within the afterloader itself, connected to
indicator lights on the treatment console, above the entrance door and on the
source container (GammaMed 12i - alarm threshold ~1 mR/hr).  The second is a
visual alarm (Primalert 10 - alarm threshold ~1.5 mR/hr), located on the wall in
the room, visible as you enter the room, within 10 feet from the nominal 10
Curie Ir-192 source.  The third is located just outside the shielded door which
has both visible and audible alarms (Primalert 35 - alarm threshold ~1 mR/hr). 
Anything that leaves the room, must pass within 50 cm of this monitor, which is
always watching.  They are operationally checked and documented each day before
use.  However, the NRC, in our license review, insisted that a hand held survey
still had to be performed (Eberline E-120G).  

This was because of a single incident in Indiana, Pennsylvania where a physician
ignored an in-room monitor which indicated that the source was still out.  It
just goes to show you that the weakest link is poor training and inattention by
personnel.  

The important thing is to emphasize the operational checks and the requirement
to stop operations if any alarms are not not functional.  Daily alarm check
requirements will make the operators aware of their use and confident in their
indications.  I would also highly recommend audible alarms at doors to shielded
irradiation facilities.  When they go off, they're awfully hard to dismiss or
ignore!

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Michael J. Bohan, RSO   |  e-mail: mike.bohan@yale.edu
Yale-New Haven Hospital |    Tele: (203) 785-2950
Radiological Physics    |     FAX: (203) 737-4252
20 York St. - WWW 204   |    As usual, everything I say may be plausibly
New Haven, CT    06504  |    denied at my employer's convenience ...
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