Re: Dosimeter Location

[gu9@ornl.gov (Robert J. Gunter)]

Shifting back to the DOE world, the guidance for 10 CFR 835 states that
multiple dosimeters should be used when "radiation fields vary by more than
50%  over the area of the whole body and the anticipated dose is greater
than 100mrem (1mSv)."  I'm sure there must be some similar guidance for 10
CFR 20.  This statement is for whole body monitoring.  Use of shielding will
probably vary the field sufficiently.

Similarly, the same guidance (G-10 CFR 835/C2 - Rev. 1, November 1994) says
you only need to monitor lens of the eye if the worker is expected to
receive more than 1.5 rem LDE dose in 1 year.  This guidance specifically
mentions X-ray machines and penetrations in shields.  Check NRC (10 CFR 20
guidance) for a similar statement.

Rob Gunter

At 08:02 PM 9/26/95 -0500, you wrote:
>     The purpose of the dosimeter is to document the exposure in the area 
>     where it is worn. From it's readings, a dose is assigned. If the 
>     dosimeter is worn under the shield, the most likely scenario is that 
>     the net result will be 0 mrem, or some number <10 mrem which is what 
>     most processors consider the lower limit for reporting a dose. While 
>     the organs of importance are under the shield, the individual who is 
>     wearing the dosimeter is assured that there was in fact no exposure. 
>     On the other hand, a shielded dosimeter provides no information 
>     whatsoever regarding the LDE dose (Lens of the eye dose equivalent). 
>     One would be asked at some point to validate that the lens didn't 
>     receive a dose that could have caused cataracts, for instance. 
>     
>     Just some food for thought. Maybe 2 dosimeters are in order. One to 
>     validate the DDE is < some desired result, and another dosimeter to 
>     record LDE. I would rather see one dosimeter worn, outside of the 
>     shield, unless it can be demonstrated that the lens of the eye is also 
>     shielded to the same degree as the area under the thyroid shield.
>     
>     Sandy Perle
>     Supervisor Health Physics
>     Florida Power and Light Company
>     Nuclear Division
>     
>     (407) 694-4219  office
>     (407) 694-3706  fax
>     
>     sandy_perle@email.fpl.com
>
>
>______________________________ Reply Separator
_________________________________
>Subject: Dosimeter Location
>Author:  radsafe@romulus.ehs.uiuc.edu at Internet-Mail
>Date:    9/26/95 4:32 PM
>
>
>HELP!!  I am caught in an existential loop.  I have been going around and 
>then some regarding wearing of personal dosimeters in radiologic locales.  I 
>have no trouble with film badge (or TLD) on collar outside leaded apron.  
>     
>I need policy (in writing) for the location of said dosimeter when a thyroid 
>shield is worn.  I have always instructed to wear UNDER the thyroid shield, 
>but I cannot find anything IN WRITING one way or the other.  Does anyone out 
>here have definitive answer and documentation as to correct location.
>     
>Thanks in advance as usual.
>     
>richard
>     
>kayrs@peak.org
>http://www.peak.org/~kayrs/
>Richard Kay, MSc, RT(R)
>     
>     
>             KNOWLEDGE IS THE FIRST PREREQUISITE IN RADIATION SAFETY 8^)
>     
>
>
>
Robert J. Gunter
Lockheed Martin Energy Systems, Inc.
Oak Ridge National Laboratory
P.O. Box 2008 
Bldg: 105MIT Mail Stop 6494
Oak Ridge, TN 37871-6494
PH:  (615) 576-6317
FAX: (615) 576-8593
email: gunterrj@ornl.gov