Some points have been made, that lack some background and thus may be interpreted differently (and in some people's opinion, wrongly)
The Stochastic risk model is is based on more than just the Life Span study (Japanese WW2 exposures) . I can think of at least 3 others off the top of my head with large numbers, from the days when we did crazy things with radiation. (TB screening/Past Ankylosing spondylitis and Breast mastitis treatments). I say crazy, because of what we know now. Then, with the knowledge available,it was considered a good idea. The "body" of evidence for radiation hormesis, is significantly smaller than that for the LNT model. Not even comparable. With what is currently known, finding a person, or even proving one existed, who has benefited from radiation hormesis is as unlikely as finding the "unlucky" person who develops a tumour from his 20 microSievert Chest Xray. Besides, finding that 1 in 2 million person is not the proof that the LNT model requires to prove it exists. That is similar to stating that, because non smokers can also develop lung cancer and one cannot definitively prove that the specific cancer in a specific smokers chest was caused by smoking, that smoking is not directly linked with cancer. As Jim put it, the more you bet, the "better" your chances. With radiation, you dont know you've "won" with a bet today, till some years down the line. So in the meantime your risk accumulates because you keep betting everyday on an event some years into the future. Just like smoking. (Jim rightly points out, that not all radiation associated lesions are life threatening. As an aside, the modern radiation protection figures consider morbidity as well.) Radiation protection standards are reviewed every few years based on what is known and they do change. The Life Span study is still not complete, as a large portion of the survivors are still alive. Who knows, maybe hormetic effects are proven in the Life Span study and the world will change its practice? We are not blindly following the numbers from the 1950's. Hormesis is not a new concept and is not confined to radiation. Even though there is very little known about it, I like to think it exists. But I personally am not going to bet on it without further evidence. I dont think the LNT and hormeses theories/models/hypthesies are entirely mutually exclusive. The dose vs risk graph may be linear but have a dip in it or start at a negative risk, for small doses. So to be controversial, I'm going to state: Flying a Blanik may be beneficial to your health, if you survive the flight, due to the possible hormetic effects afforded by the low dose radiation from the instruments. This may, however, be negated, if you choose not to wear your sun hat. Cheers AJ 2008/8/1 Mike Borgelt <[EMAIL PROTECTED]> > At 07:36 PM 31/07/2008, you wrote: > >> The stochastic risk is the luck (or bad luck) factor of radiation. i.e. >> even a very low dose of radiation can cause a DNA mutation and subsequent >> cancer, if it hits the right spot! This is completely random but like a bet >> at the races, the higher the dose, the better the chance of developing >> cancer. For example, for every 2,000,000 chest x-rays (0.02mSv) one will >> give the patient cancer that is life threatening. >> > > > While I know your work involves this, Jim what you are referring to is the > Linear No Threshold (LNT) hypothesis and is based on the Hiroshima and > Nagasaki exposures. However you'll never find that person out of the 2 > million or even prove that he or she ever existed due to the large and > variable natural background of cancer rates. So LNT will always remain a > hypothesis. (This reminds me of another current scientific issue)However > there is a body of evidence like the Taiwanese case which shows that small > doses of radiation may not only be harmless but may confer some health > benefits. This is not just a correlation but there are body mechanisms that > repair damage to cells and DNA so there is a plausible mechanism invovling > stimulation of these repair mechanisms by small radiation doses. > It also means that the damage is not necessarily cumulative. > > This is different from ingesting radioactive material which results in very > high doses to body tissues around the particles. > > I have seen an article (Jaworwowski - former chairman of the radiological > Protection Board in Poland) that said that international radiological > protection standards which were set in the 50's were set to very low doses > at the insistence of the Soviets to hobble western use of nuclear power and > nuclear weapons. The Soviets weren't going to be bound by them of course. > > > Mike > Borgelt Instruments - manufacturers of quality soaring instruments > phone Int'l + 61 746 355784 > fax Int'l + 61 746 358796 > cellphone Int'l + 61 428 355784 > Int'l + 61 429 355784 > email: [EMAIL PROTECTED] > website: www.borgeltinstruments.com > > _______________________________________________ > Aus-soaring mailing list > Aus-soaring@lists.internode.on.net > To check or change subscription details, visit: > http://lists.internode.on.net/mailman/listinfo/aus-soaring >
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