RE: To Luxel Users

["Ceffalo, Grant M" <GMCeffal@mail.bhi-erc.com>]

I don't see Sandy's comments so much as badmouthing the competition as
questioning a practice.  I, too question the wisdom of a 1-mrem reportable
dose.  The NVLAP LLD formula can statistically demonstrate that the dose is
resolvable, but is it meaningful?  The LLD formula is based on a small group
of dosimeters that were all treated very similarly, not spread all over a
campus or industrial plant.

In many locations where the Luxel badge is used, the monthly 'background'
variation from construction materials can easily vary by more than 1 mrem.  

Most good dosimetry algorithms can resolve dose much lower than the minimum
reported dose, but most dosimetry companies do not report to the minimum
resolution.  Some variation must be accommodated for, both at the site and
in transit.

I think that the Luxel technology is really spiffy new technology, and I
believe that it can easily see 1 mrem, but does 1-mrem have any significance
given the background and transit variations?

Grant Ceffalo, CHP
former dosimetry engineer

My comments do not reflect the opinion of any of my employers, past or
present

-----Original Message-----
From: John R Laferriere [mailto:John.R.Laferriere@dupontpharma.com]
Sent: Monday, March 27, 2000 5:02 AM
To: Multiple recipients of list
Subject: Re: To Luxel Users



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Content-type: TEXT/PLAIN

Sandy- Maybe I'm being paranoid, but I think you are crossing the line here
between voicing legitimate opinions about a new dosimetry technology and
inappropriately using Radsafe as a forum for badmouthing your main
competitor.  I suggest you proceed very cautiously lest you incur the wrath
of Melissa (if she is still out there) and the distain of your fellow HP
professionals.


Regards,

John R. Laferriere, CHP
DuPont Pharmaceuticals Co.
Medical Imaging Division
john.r.laferriere@dupontpharma.com
(978) 671-8316   fax (978) 671-8149



	sandyfl@earthlink.net
	03/25/00 10:20 AM
		 
		 To: radsafe@romulus.ehs.uiuc.edu@SMTP
		 cc: (bcc: John R Laferriere/CORP/Pharma)
		 Subject: Re: To Luxel Users

Mike Lantz stated:

>  If these reported measurements are not facility-related work but
> are simply due to area variations, what good is a minimum reportable dose
of 1
> mrem? 

One might also ask, if the regulatory limits are 1250 mrem/qtr, or, 
5000 mrem/yr (TEDE), why measure dose at 1 mrem at all, even if 
this can be attributed to occupational exposure? In my opinion, 
reporting and recording dose down to 1 mrem "gives significance to 
the insignificant."

Another question: If the net dose reported is 1 mrem, how is the 
Control Badge dose measured where a net dose of 1 mrem can be 
reported? What is the statistical significance of the Control Badge 
response and how is this response converted to dose? What is the 
Process Capability whereby the variance of the process is defined 
to the point that a dose is either determined to be real, or, false? 
To be statistically valid, in my opinion, any measuring system has 
to have enough data to be analyzed, so how does one do that if the 
minimal dose is 1 mrem? Does the system actually determine 
dose at 0.1 mrem, and therefore, there is a rounding off factor?

Anyone have insight, or asked that question when obtaining your 
dose reports? NVLAP only tests dose down to 30 mrem. Going 
from 30 to 1 mrem is a big jump. What's the basis?
----------------------------------------------------------------------------
------------
Sandy Perle     Tel:(714) 545-0100 / (800) 548-5100            
Director, Technical    Extension 2306           
ICN Worldwide Dosimetry Division  Fax:(714) 668-3149

ICN Biomedicals, Inc.    E-Mail: sandyfl@earthlink.net

ICN Plaza, 3300 Hyland Avenue    E-Mail: sperle@icnpharm.com

Costa Mesa, CA 92626



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