[ RadSafe ] LNT Dogma? - Future of Radiation Safety Regulations

Thu Aug 20 18:42:26 CDT 2015

Radsafe,
      The things one measures are not always the parameters one is
looking to estimate.  See books on Kalman Filtering by Gelb,
Jazwinski, R. Grover Brown, JV Candy etc.   Kalman Filters are used in
rocket and plane (and submarine) guidance and navigation systems.
     Another advanced modeling technique is Monte Carlo modeling, such
as is done in MCNP (monte carlo neutral particle program).  If you
start using MCNP, you'll probably never give anyone a straight
(simple) answer again.  You'll speak in terms of probability.  For
things in radiation, Poisson statistics may be more proper to use than
Gaussian statistics.  MCNP --- see ORNL RSICC (Rad Shielding Info
Center).
     Joe Preisig


On 8/20/15, Joseph Preisig <jrpnj01 at gmail.com> wrote:
> Radsafe,
>
>      Some models are better than others.  Don't use too few fitting
> parameters.  Don't use too many fitting parameters.  Use an optimal
> number of fitting parameters.
>
>      A model is posed to start to understand some physical process.
> Once the model is posed, one can look how the measured data look with
> respect to the model.  Do data fitting and perhaps a chi-square test
> to see how well a model is doing.  Modify the model if necessary.  Can
> one really extrapolate a model in LNT down into the low-dose region,
> rigorously???  Probably not.
>
>      Joe Preisig
>
>
>
> On 8/20/15, Brennan, Mike  (DOH) <Mike.Brennan at doh.wa.gov> wrote:
>> Hi, Dr. Doss.
>>
>> With all due respect, I must disagree.  I can understand believing LNT is
>> probably wrong, but still using it.  One of the epiphanies I've had (I've
>> had four) is "All models are wrong and some are useful".  Models are not
>> reality, but simplifications of reality.  It is possible to understand
>> that
>> a model fails in some aspects but still use it productively.
>>
>> One of the clearest examples I've encounter was when I was a submariner,
>> involving the Ekelund technique for finding the range to a contact using
>> passive sonar
>> http://www.navy.mil/navydata/cno/n87/usw/issue_15/ekelund.html.  It is an
>> interesting bit of dynamic geometry, that can only be done by assuming as
>> true three things that are known (not suspected, but known) to be false.
>> If
>> you make that assumption, you can get a range good enough to shoot a
>> torpedo
>> with.  If you don't make that assumption, you can't solve the problem.
>>
>> As for LNT, my "gut feeling" is that there are a lot of variables, many
>> of
>> which are unknown and some may well be unknowable with current
>> technology.
>> I believe that for many different types of radiation exposure (and I am
>> not
>> a fan of trying to lump them all together) there are likely thresholds
>> below
>> which no increase in cancer would be observed, but I suspect those
>> thresholds differ from person to person, and possible for an individual
>> over
>> the course of their life, based on many factors.
>>
>> As for hormesis, again my gut feeling is that it is not a direct
>> phenomenon,
>> in that "X exposure causes Y reduction in cancer", but rather "X exposure
>> can cause Y change in something, which can cause Z change in response to
>> cancer and/or cancer causing stimuli".  I think that both our
>> understanding
>> of cancer (which more and more I feel is not a useful term, as it lumps
>> too
>> many different things together) and hormesis.  I, personally, would like
>> to
>> see hormesis make a serious run on LNT, but I think it will have to be
>> pretty impressive to overcome the dogma.
>>
>>
>> -----Original Message-----
>> From: radsafe-bounces at health.phys.iit.edu
>> [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Doss, Mohan
>> Sent: Thursday, August 20, 2015 12:35 PM
>> To: The International Radiation Protection (Health Physics) Mailing List
>> Subject: Re: [ RadSafe ] LNT Dogma? - Future of Radiation Safety
>> Regulations
>>
>> Dear All,
>>     It is ironic that the individual quoted below believes the LNT model
>> is
>> almost certainly wrong, and still is a strong proponent of the model. If
>> one
>> believes some concept is wrong or is almost certainly wrong, one should be
>> a
>> strong opponent, not a strong proponent of that concept. If the statement
>> by
>> this individual is the best summation of the LNT model, it is really a
>> pathetic situation (for the LNT model).
>>     Keeping in mind the accepted criterion that book-keeping should be
>> made
>> easier, in contrast to the LNT model (which is almost certainly wrong, as
>> stated by the strong proponent - I accept his judgement), the radiation
>> hormesis model (which is almost certainly correct, as stated by me, a
>> strong
>> proponent, because there is plenty of data supporting it - see
>> presentation
>> at link below), if used for regulations, would simplify book-keeping
>> tremendously, as no book-keeping need be required for low-doses, since
>> cancer risks would be lowered by low-dose radiation. The current
>> proponents
>> of the LNT model (who desire simpler book-keeping) should welcome this!
>> The
>> regulations should of course require book-keeping for potential high dose
>> situations, but these would be few and far between.  There is a wide gap
>> that separates low doses that are beneficial from high doses that are
>> harmful, and so it would be easy to separate the two situations, and
>> require
>> book-keeping only for the latter. I discussed this concept for radiation
>> protection regulations (for the future, if radiation hormesis concept is
>> accepted) at the recent HPS Annual Meeting in the Low-dose symposium. If
>> anyone is interested in viewing the presentation, it is available in
>> ResearchGate at: https://goo.gl/A7EcfB . I welcome comments and
>> criticisms,
>> either in this forum or via private email. Thanks.
>>    With best regards,
>>                                           Mohan
>>
>> Mohan Doss, Ph.D., MCCPM
>> Medical Physicist,
>> Associate Professor, Diagnostic Imaging, Fox Chase Cancer Center,
>> 333 Cottman Avenue,
>> Philadelphia, PA 19111-2497.
>> Phone: 215 214-1707
>> Website: http://www.fccc.edu/research/pid/doss/
>> Blogs: http://mohan-doss-home-page.blogspot.com/
>>
>> -----Original Message-----
>> From: radsafe-bounces at health.phys.iit.edu
>> [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of KARAM, PHILIP
>> Sent: Tuesday, August 18, 2015 3:36 PM
>> To: The International Radiation Protection (Health Physics) Mailing List
>> <radsafe at health.phys.iit.edu>
>> Subject: Re: [ RadSafe ] LNT Dogma?
>>
>> The best summation of LNT that I've heard was from a strong LNT proponent
>> (sorry - can't remember his name at the moment). In a discussion after
>> some
>> presentations he said "LNT is almost certainly wrong, but it makes the
>> book-keeping easy."
>>
>> According to the final arbiter of all knowledge (Wikipedia) "Dogma is a
>> principle or set of principles laid down by an authority as
>> incontrovertibly
>> true. It serves as part of the primary basis of an ideology or belief
>> system, and it cannot be changed or discarded without affecting the very
>> system's paradigm, or the ideology itself."
>>
>> LNT is not scientific dogma, but it has effectively become dogma for the
>> ALARA philosophy, and near-dogma for regulatory, national, and
>> international
>> advisory bodies. And I would say that it is certainly dogma for all of
>> the
>> anti-nuclear and anti-radiation groups.
>>
>> Andy
>>
>> -----Original Message-----
>> From: radsafe-bounces at health.phys.iit.edu
>> [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Franz
>> Schönhofer
>> Sent: Tuesday, August 18, 2015 3:27 PM
>> To: The International Radiation Protection (Health Physics) Mailing List
>> Subject: Re: [ RadSafe ] LNT Dogma?
>>
>> RADSAFErs,
>>
>> Anybody really knows, what a "Dogma" is? Look it up on Google. LNT does
>> not
>> fit to this definition. Especially LNT is lively debated and not taken
>> for
>> granted by many scientists. Therefore it cannot be called a Dogma.
>> However
>> having been a lawmaker I confess, that the concept of LNT has its great
>> advantage!!!!! Now load your guns, fill your flaming devices- I`ll be
>> able
>> to stand it and anyway I am used to flaming. Compared to Austrian
>> ministery
>> intrigues this is a "sweet nothing"!
>>
>> Best regards!
>>
>> Franz
>>
>>
>>
>>
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>