Thursday, February 28, 2013

Unconventional Wisdom 1


A continuation of Conventional Wisdom posted August 8, 2011.

“Listen up, Julie.  I’m going to teach you that exposure to small amounts of radiation won’t hurt you.  In fact, it may even be good for you, even at the levels used for diagnostic purposes such as computed tomography (CT) scans.  Recent research has shown that living in a radiation-deficient environment stunted the growth of a protozoan.  And living in a radiation background that is several times our present level should improve our health and longevity. (Google Sir Samurai T. D. Luckey.)”

“Get off it, Curmudge!  I’ve been taught since I was a child that all radiation is dangerous.  Old men are supposed to dream dreams (Acts 2:17), but isn’t this one pushing the envelope?  And besides, blogs are too brief to teach anything.  The most they can do is inspire the reader to learn more.”

“Right as usual, Julie.  Our teaching—I mean exposure—to this topic began over a year ago (August 8, 2011) in our posting on Conventional Wisdom.  At that time we still had a sponsor and had to tread softly on controversial topics.”

“Hooray! Vive l’indépendence!  Now we can tackle controversial issues head-on.”

“Whoa, Ms. Enthusiasm.  As I said, we introduced today’s topic, the linear no-threshold (LNT) concept, in 2011. To avoid repeating everything, let’s all go back and read the Conventional Wisdom posting.”

[Blog delayed 10 minutes for Jaded Julie and readers to read old posting.]

“Now I remember, Curmudge.  According to the linear no-threshold theory a plot of cancer occurrence vs. exposure, based on high levels of exposure to radiation, could be extrapolated to the origin, i.e., there was no threshold below which there was no effect.”

“That’s it, all right.  But extensive research has shown the LNT theory to be invalid.  We cited some of it in our earlier posting, and we’ll list more books and papers today.  If our readers study the documents that we cite, most should agree that the LNT theory has become outmoded.  However, there will likely be some who will cling to the LNT dogma.”

“Also in our Conventional Wisdom posting there were references suggesting that exposure to low-level radiation imparted a protective effect against cancer.  Will we discuss that also?”

“We surely will, Julie, but it may require more than a single posting.  There’s so much information on these topics that we’ll only have room in the blog to mention authors and brief summaries.  Complete references are in Hiserodt’s book, discussed below.  And to examine these documents critically, a reader will need to become familiar with the units used to measure radiation, which we don’t have space to cover.”

“But Curmudge, we’ll need to use some numbers, and readers will require a few units to even gain a seat-of-the-pants understanding of our story.”

“Good observation, Julie.  Here are some common abbreviations and units:
Abbreviations: m = milli or 1/1000; c = centi or 1/100.
Rem is effective dose in U.S. units; sievert (Sv) [gray (Gy) is equivalent] is effective dose in international units.  1 Sv = 100 rem.  1 cSv =  1,000 mrem.”

“How about providing a frame of reference?”

“Here are some ballpark values:
Typical background radiation (cosmic, terrestrial, radon, medical) in the U.S. = 300 mrem (0.3 cSv) per year.  Background in Denver = 600 mrem (0.6 cSv).
Maximum permissible exposure for a nuclear worker = 5,000 mrem (5 cSv) per year.
Acute exposure (1-2 days) to cause radiation sickness = 100,000 mrem (100 cSv).”
A single computed tomography (CT) scan = 1,000-5,000 mrem (1-5 cSv).”

“Thanks, Old Guy.  Now we all should be on the same page.  Shall we begin our discussion by mentioning the books on this subject that are available?”

“To easily obtain the most information at a reasonable price ($5.91 from Amazon), I recommend Ed Hiserodt’s Underexposed (subtitled What if radiation is actually good for you?) (2005).  Despite its easy-reading appearance, the scientist or nonscientist will likely agree that much of the story is there, and that it is supported by a comprehensive Amazon review by Jay Lehr.  Books with more detail and a much higher price include Radiation Hormesis by T. D. Luckey (1991) and Radiation Hormesis and the Linear-No-Threshold Assumption by Charles L. Sanders (2009).  These books are well documented with peer-reviewed literature.  Luckey’s two books—an earlier one was published in 1981—contain over 2,00 citations.”

“Well Curmudge, I can guess which book a very familiar tightwad bought.  Prof. Luckey is revered in Japan, where they accorded him the honorary title of Samurai.  This can be confirmed by ‘googling’ Sir Samurai T. D. Luckey, where many of the teachings of this blog are also supported.  By the way, I noticed that the books by Luckey and Sanders have hormesis in their titles.  Perhaps you can tell us what hormesis means.”

“It’s the protective effect mentioned by Tubiana in Conventional Wisdom.  And more generally, it’s the phenomenon where something that is harmful at high doses is helpful at low doses.  Examples are many trace metals, vitamins, and even water.  So to proceed, in addition to the papers cited in our Conventional Wisdom posting (those by Vaiserman, Tubiana et al., and Scott et al.) the following tend to refute the LNT theory and support the radiation hormesis concept.  We’ll start with the early observations, made mostly by Japanese scientists, on survivors of the atomic bomb attacks on Hiroshima and Nagasaki.”

“Chapter 15 in Hiserodt shows plots of cancer deaths vs. exposure.  Because plots are hard to show in this blog, I trust, Old Guy, that you can describe them.” 

“A ‘hockey stick’ plot of effect vs. exposure (with blade to the left coinciding with data on unexposed controls) would have refuted the LNT theory.  These plots were shaped like field hockey sticks with blades drooping below controls, thus demonstrating radiation hormesis (fewer deaths than controls) below around 10 cGy.”

“Curmudge, with those exciting findings published in Health Physics and seemingly ignored since 1987, let’s take a few days to search the books further and find some more data.  Sayonara.

Kaizen Curmudgeon                                               


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