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Re: respiratory tract dose
You're exactly right. Some internal dosimetry cases require considerable
expertise for proper evaluation, but the case posed by Mr. Creed may be amenable
to a very simple analysis. According to Federal Guidance Report No. 11, Table
2.1, the effective inhalation dose factor for Sc-46 is 8.01E-9 Sv/Bq, or 29.6
mrem/uCi. So for 3.75 uCi of Sc-46, the dose is 111 mrem CEDE. This should be
the worst case estimate (if particle size were known a lower dose might be
calculated due to diversion of activity to the GI tract), which is usually what
is required for a license amendment. Correct me if I'm wrong; there may be
something about the problem I'm not aware of. But in any case, this is not
exactly rocket science!!
"NIXON, Grant (Kanata)" wrote:
> If quick and dirty calculations and models were not available (as has
> already been devised via the MIRD method if I am not mistaken) then I would
> think that there would be very few CHP's that could do their job at all. All
> CHP's would then need to be Monte Carlo experts (e.g., using MCNP) with a
> very good model for describing the geometry and attenuation properties of
> human-tissue. Such codes already exist in validated form and are used by
> consultants and other experts (including some CHP's). Please note that such
> extensive modeling knowledge generally falls outside the scope and
> competence of most CHP's.
>
> Perhaps the individual in question should consult the book "Radiological
> Assessment" by Shultis and Faw. I do not have a copy at this time but I
> think that the MIRD method is discussed therein in a format that is very
> accessible to the average "smart fellow".
>
> Best regards and good luck,
>
> Grant
>
> -----Original Message-----
> From: Vincent King [mailto:slavak@attbi.com]
> Sent: Wednesday, May 14, 2003 1:52 PM
> To: radsafe@list.vanderbilt.edu
> Subject: Re: respiratory tract dose
>
> Radsafers,
>
> I think the point has been that performing internal dose calculations are
> more complicated than grabbing a quick reference or formula and popping out
> the right answer, not that people don't want to help. Internal dosimetry is
> an entire specialty of health physics. People who have the required "skills
> and knowledge" understand this, and some have been tactfully (or not so
> tactfully) trying to express this.
>
> Since the original question mentioned licensing, I have to assume that NRC
> or Agreement State oversight is somehow involved. This implies that an
> acceptable approach - from the regulators point of view - is necessary (not
> to mention that if this "estimate" is done incorrectly, there could be legal
> ramifications down the road for whatever facility/company is involved).
>
> I commend Mr. Creeds efforts to attempt to address his issue, and I'm not
> knocking the exchange of available technical information via Radsafe. But
> assuming a non-HP can be taught to perform internal dosimetry calculations
> with a quick Radsafe answer crosses the line. I'm an EMT, but if I had a
> family member who required surgery, I wouldn't log in to a medical list
> server to try to get tips on how to do it myself. In fact, if I'm ethical,
> my limited medical training would compel me to seek a qualified specialist.
> Not knowing the details of Mr. Creed's situation, I won't speculate on how
> rigorous his answer needs to be - that's his call.
>
> I also agree that any rudeness toward him is completely unwarranted (and,
> for Health Physics Society members, also stands in contrast to the HPS
> ethic: "Members will gladly accept every opportunity to increase public
> understanding of radiation protection and the objectives of the Society").
> But I find myself in the position of having to agree with Bill Lipton's
> point that too many "meter swingers" think they can answer any health
> physics question, regardless of their areas and levels of competence.
>
> Vincent King,
> Grand Junction, CO
>
> ----- Original Message -----
> From: "Mercado, Don" <don.mercado@lmco.com>
> To: "'William V Lipton'" <liptonw@DTEENERGY.COM>; "Kevin Creed"
> <creed@humboldt.edu>
> Cc: <radsafe@list.vanderbilt.edu>; "Luke George" <tlg2@humboldt.edu>
> Sent: Wednesday, May 14, 2003 9:38 AM
> Subject: RE: respiratory tract dose
>
> He wasn't
> > asking you to do the work for him, just supply the formulas and references
> > to him and he'd do the work! Are you so unsure of your own skills and
> > knowledge that you can't even do that????
>
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