[ RadSafe ] LNT Seminar Given at LANL On 11/10/05

howard long hflong at pacbell.net
Sat Nov 12 19:10:16 CST 2005

Much appreciated.
Howard Long

"Scott, Bobby" <BScott at lrri.org> wrote:
Dear colleagues:

The partial abstract below relates to my most recent LNT-associated
presentation. If you would like to receive a pdf version of the seminar
slides please let me know via e-mail. The pdf file will also be
available within a couple of weeks via our website:
http://www.radiation-scott.org .


Bobby R. Scott

E-mail: bscott at LRRI.org

Seminar Presented by: Bobby R. Scott, Ph.D.

Affiliation: Lovelace Respiratory Research Institute

Title: The LNT Hypothesis May Have Outlived Its Usefulness

Seminar Location: Los Alamos National Laboratory, Health, Safety, and
Radiation Protection Division

Seminar Date: November 10, 2005

Abstract: "The linear no-threshold (LNT) radiation risk model has been
used in radiation protection standards for over 50 years. Yet there is
significant debate among scientists whether this model is appropriate
for protecting people at low doses and dose rates of radiation. Based
mainly on cancer data from the essentially instantaneous radiation
exposures from nuclear blasts in Hiroshima and Nagasaki, the National
Academy of Sciences BEIR VII Report concluded that the available data
for low linear-energy-transfer (LET) radiation were consistent with the
LNT hypothesis. Accordingly, risk is constrained to be elevated for any
amount of radiation, even for background radiation, whose dose rates are
more than 10 orders of magnitude less than for the A bombs survivors.
Thus, BEIR VII concluded that background radiation is harmful, even
though there is no evidence for such harm. The Committee Chair went so
far as to suggest that persons residing at high altitudes (e.g. such as
persons residing in Los Alamos), may want to move to a lower altitude to
reduce their level of cosmic-ray exposure.

This presentation will focus on reasons for abandoning the use of LNT
for low-dose, low dose-rate risk assessment. Results will be presented
supporting the view that low doses and dose rates of low-LET radiation
(or low- plus high-LET radiation) protect us from cancer and possibly
other diseases. Three protective processes are now recognized as being
induced by low-LET radiation: 1) induced high fidelity DNA
repair/apoptosis; 2) a novel protective apoptosis-mediated process,
which selectively removes genomically compromised cells; and (3) immune
system stimulation. These mechanisms are incorporated into a novel
hormetic relative risk model that accounts for these protective

A news media report describing BEIR VII as a "trillion dollar mistake"
is on target. Further, LNT will aid terrorists in the case of a
dirty-bomb incident. Radiation-phobia related casualties are far more
likely following a dirty-bomb incident than are casualties directly
related to radiation exposure. As a point of reference, more than
100,000 radiation-phobia-associated abortions were reported to have
occurred in Western Europe just after the Chernobyl accident, a tragic
loss of life."

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