| Let me quote from your own source: "There have been numerous biological experiments conducted, with nonhuman organisms, that demonstrate that the rate at which radiation dose is delivered can affect the extent of biological response. Thus a sufficiently high dose delivered over a period of a few minutes may be expected to have a greater biological impact than the same dose spread over a year." The only question is what constitutes a "sufficiently high" dose, due to extrapolation. See 5). THEIR OWN POSITION PAPER on backscatter scanners recommends per-screening and per-year (time limit!) maximums FAR below the threshold that they claimed wasn't a problem in the first place -- see 8). 4) Further, the terse "no" answer looked disingenuous. The cited position paper link was broken but I tracked it down. It appears to be "Radiation Risk in Perspective", PS010-2 (which I assume is the updated version of PS010-1). It has nothing to say about doses over short time periods. http://www.hps.org/hpspublications/positionstatements.html 5) The issue seems to be that there is very little data about low-dose exposures, so regulations are based on extrapolation from high-dose exposures. See http://www.ncrponline.org/PDFs/TST_NRC%20_04-08-08.pdf (third slide) 6) What it does say is this: "the Health Physics Society recommends against quantitative estimation of health risks below an individual dose of 5 rem in one year or a lifetime dose of 10 rem above that received from natural sources." 7) The whole point of their objection was that we lack the empirical evidence to extrapolate from high doses to low doses. Then the article you cite does exactly that. They go from saying, "we lack proof that the answer is X" to saying, "the answer is ~X". 8) The recommended standard "limits the reference effective dose delivered to the subject to 0.25 microsieverts (25 microrem) per screening. Additionally, a screening facility should not expose any individual to more than 250 microsieverts (25 millirem) reference effective dose in a year." "Use of Ionizing Radiation for Security Screening Individuals" PS017-1 http://www.hps.org/hpspublications/positionstatements.html How they can go from saying in the first paper, "However, below 5–10 rem (which includes occupational and environmental exposures), risks of health effects are either too small to be observed or are nonexistent" to supporting a maximum of 0.025 rem per year is entirely unclear. Except that the Health Physics Society seems to have turned into a pro-industry spokesgroup. The current president works for Dade Moeller, who are embroiled in a number of controversies, to put it lightly. A lot of extremely damaging information is cited in the original link below. ""Hirsch then zeroed in on Dade Moeller’s radiation plan and on the controversial company itself, whose namesake testified back in the 1990s that money spent on cleaning up Cold War-era nuclear facilities was being wasted since there would be a cure for cancer." Original comment: http://news.ycombinator.com/item?id=1889673 |
>...How they can go from saying in the first paper, "However, below 5–10 rem (which includes occupational and environmental exposures), risks of health effects are either too small to be observed or are nonexistent" to supporting a maximum of 0.025 rem per year is entirely unclear.
Where they support that 0.025 rem/year recommendation, they explain that the point is to keep "individual doses as low as reasonably achievable (ALARA) while achieving the desired objective." (Same source, PS017-1).
And you mischarcterize their claims. HPS does not claim <5 rem doses are "not a problem" -- they said the effects are such are "either too small to be observed or nonexistent". (It does not follow that a health effect too small to be epidemologically noticable is "not a problem"). "Too small to be observed" is NOT a quantifier of significance; it is an explanation for the lack of empirical observations. That position statement (PS010-2) is a recommendation against quantiative estimation of the effects of <5 rem radiation doses, not an assertion of their absolute safety.
>It appears to be "Radiation Risk in Perspective", PS010-2 (which I assume is the updated version of PS010-1). It has nothing to say about doses over short time periods.
It does not appear to have been referenced for that purpose.