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Re: Fwd(2): Re: badge sensitivity topic



Ray Carroll said the following:

> NVLAP is about ensuring that the TLD processing is accurate and responds
> correctly to the types and energies of radiation to be measured.

The purpose of NVLAP was to establish "minimum" requirements 
for a dosimetry processor. The CFR that establishes NVLAP 
(15CFR285) requirements in reality does not concern itself with 
assuring the accuracy and precision, except to the L value 
contained within ANSI N13.11-1993. If one is within these values, 
currently set at 0.3 for Categories I and II, and 0.5 for Categories III 
through VIII, the processor is deemed capable for accreditation. 
The other criteria is to successfully pass the on-site assessment. 
Therefore, an processor who is NVLAP accredited, can be that 
way, even if they are +/- 50% from a known dose, through the 
proficiency testing. There is currently a max of 0.35 for either the 
bias or the std. dev. value, but that has been proposed to be 
eliminated within the review of the current standard, up for revision 
at this time.

In summary, a facility needs to look more at the processor of their 
choice, and not just at the fact that they have a NVLAP certificate. 
One can be accurate within 1% and one can be accurate within 
50%, and BOTH be NVLAP accredited.

NVLAP is a good thing. It has improved the dosimetry programs 
since implementation in the late '80s. It is not the panacea though. 
There are still good processors, and there are those that are not as 
good. I have first hand knowledge of this, in that I have been 
conducting NVLAP on-site assessments since 1993. I just can't 
assess other commercial processors any more!!!!   :>

------------------
Sandy Perle
Technical Director
ICN Dosimetry Division
ICN Plaza
3300 Hyland Avenue
Costa Mesa, CA 92626
Office: (800) 548-5100 x2306 
Fax:    (714) 668-3149
  
sandyfl@earthlink.net
sperle@icnpharm.com

ICN Dosimetry Website:
http://www.dosimetry.com

Personal Website:
http://www.geocities.com/CapeCanaveral/1205

"The object of opening the mind, as of opening 
the mouth, is to close it again on something solid"
              - G. K. Chesterton -

The opinions expressed are solely, absolutely, positively, definitely those of the author, and NOT my employer
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