Re[2]: Dosimeter Location

["Patricia Edgerton" <HW1.PEDGERTO@HW1.CAHWNET.GOV>]

Mea Culpa - my mind knew I was stating a dose equivalent (hence the
formula states that it is calculating a H(E), but my fingers roguishly
wrote DDE in the introductory paragraph - Sandy is right.

However, the State of California is accepting this method to calculate
dose equivalents for cardiac cath docs, interventional radiologists and
anyone else who wants to use it.  Part 20 allows people to take credit
for protective devices, ie, respirators etc.  Therefore, we allow credits
for lead aprons.  (The Q&A's for Part 20 also state that credit can be
taken for the shielding provided by eyeglasses and/or safety glasses.
See NUREG/cr-6204; question number 45.)

The usual disclaimers apply....

"Meetings:  the practical aternative to work."

*** Forwarding note from RADSAFE --HW1SMTP  09/29/95 10:40 ***
To: RADSAFE --HW1SMTP  RADSAFE

Subject: Re[2]: Dosimeter Location

Sender's Nativename=radsafe@ROMULUS.EHS.UIUC.EDU

The calculation below appears to be a calculation of an "Effective Dose
Equivalent", not a DDE. 10CFR20.1201(2)(c) states that "The assigned deep dose
equivalent and shallow dose equivalent must be for the part of the body
receiving the highest exposure. Applying any factor to a shielded badge and
adding it to an extremely small fraction of a badge worn outside of the shield
does not appear to be an accurate assessment of the highest exposure.

The optimum determination of the true DDE for regulatory purposes is to wear
the
dosimeter at that location which DOES receive the highest exposure. The neck is
part of the whole body and therefore should be the location for measuring the
DDE, not a fraction of .004 of the badge reading, plus 50% of a dose that is
most likely below reportable threshold.

Comments?


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: Re: Dosimeter Location
Author:  radsafe@romulus.ehs.uiuc.edu at Internet-Mail
Date:    9/29/95 11:41 AM



*** Reply to note of 09/28/95 20:16
The info regarding calculating a DDE based on weighting factors for one badge
worn outside of a .5mm lead apron, and one worn inside is:
H(E) = 1.5 x badge reading of dosimeter worn at waist under apron
+ .004 x badge reading of dosimeter worn outside apron at neck level.

This is formula and supporting documentation is found in the Correspondence
section of a 1994 HPS Journal.  I have just kept a photocopy of the two
pages, and those pages don't say what issue it is.  However, it does
reference:  0017-9078/94

If you want a copy faxed, write to me directly

Trisha Edgerton, Senior Health Physicist
Supervisor, Northern California Compliance
Sacramento, CA
pedgerto@hw1.cahwnet.gov
voice:  (916) 323-2753