[ RadSafe ] New Fukushima-related paper

Tue Sep 6 18:33:29 CDT 2011

Congratulations on your publication, Bobby.  In the interest of full
disclosure, perhaps people should know that The Journal of American
Physicians and Surgeons is not unlike some of the publications Chris
Busby cites, in that the name does not convey the political leanings of
the publication, though unlike those Chris cites, this one leans right
rather than left.  

As an example, the line from your Abstract, "Projected long-term
increase in cancer risk from low-dose exposures of down-wind populations
is purely hypothetical, since it is based on the discredited linear
no-threshold (LNT) hypothesis."  Attempts to finesse a rather important
point.  I, personally, have no great confidence in LNT as an accurate
model (and I have expressed that opinion a number of times in this
forum), however "discredited" is, I believe, something that has not
nearly been achieved.  I personally would love to see a set of well
designed studies that would settle the matter one way or the other (and
I believe it would not be in LNT's favor), but that hasn't happened,
yet.

I took a quick look at your article, and I have a couple of comments.  I
agree with your conclusion that barring an exceptional exposure event,
life threatening radiation damage to workers is very low, or "unlikely".
(I suspect there are actually a number of opportunities for exceptional
exposure events, not just being present when a hydrogen explosion
ruptured containment).  I suspect that the fatal cancer rate among
workers will be well below the norm, because I expect them to be
monitored within an inch of their lives, and so any cancers will be
caught early.  I reserve judgment on the effect of I-131 on people who
could not evacuate in the early days, and I also reserve judgment on
possible lung cancers from inhaled contamination, but I suspect the
numbers will not be large.  I agree that the cancer due to direct gamma
exposure in the general population will be small, probably
non-detectable, and I don't discount the possibility that it will turn
out less than expected (supporting hormesis).  I expect fatalities to be
less than in the unaffected population, again because of enhanced
monitoring and early detection.  So, in general, I mostly agree with
your conclusions.  

There are a couple of points that struck me, that you might with to muse
on for future papers.  

"Dose thresholds are required for deterministic effects because large
numbers of cells must be destroyed simultaneously to produce such
effects."
I disagree with "simultaneously".  I think a more accurate description
would be "much faster than they can be replaced".  This actually deals
with the dose rate issue as it relates to a given tissue.  Be that as it
may, if cells are being destroyed faster than they can be replaced, and
this continues long enough, then deterministic effects will occur.  If I
my reasoning is wrong here, I would be interested in see in how.

"This is not likely after low radiation doses and is less likely when
high doses are delivered at a low rate than when delivered at a high
rate."
I don't disagree, but I think this is poorly worded.  I would say
something like, "The required large number of destroyed cells is most
likely at a high dose and high dose-rate, less likely at a high dose and
lower dose rate, and unlikely at a low radiation dose."

"For example, if the cell lethality probability per cell at risk (for a
specific cell type) is 0.1 (i.e., 1 in 10 cells) at a given gamma dose,
then the corresponding probability for simultaneously killing 1 million
of these cells with the same dose is 0.1E1,000,000, which is essentially
zero."
I don't understand this.  I think you've left so much out of this for
the sake of brevity that it has lost its meaning.  If you have
established a risk of 0.1 per cell, then the number of cells destroyed
is a function of the number of cells exposed, and I don't see that in
here.  And as I mentioned above, "simultaneous" isn't necessary, just
"faster than can be fixed".  To use an imperfect analogy, a neighborhood
doesn't need to catch fire all at the same moment; even if the houses
burn one at a time, if it is faster than new house are built, eventually
the neighborhood is destroyed.  

All in all, an OK paper.

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Scott, Bobby
Sent: Tuesday, September 06, 2011 2:05 PM
To: The International Radiation Protection (Health Physics) MailingList
Subject: [ RadSafe ] New Fukushima-related paper

Hi All:

A link to my new paper titled "A guide to radiation hazard evaluation,
applied to Fukushima recovery workers" follows: 

http://www.jpands.org/vol16no3/scott.pdf

The paper was just published in the Journal of American Physicians and
Surgeons (Vol. 16, #3, pages 71-76, 2011). I thought the paper may be of
interest to some of you.

Best wishes,
Bobby R. Scott, Ph.D.
Senior Scientist
Lovelace Respiratory Research Institute
2425 Ridgecrest Drive SE
Albuquerque, NM 87108 USA

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