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Comment by ekianjo | Hacker News Reader

> If sustained for a full year, that would be 154 times the maximum possible dose of 1 millisievert per year recommended for public exposure by the International Commission on Radiological Protection.

Note that this limit has no real meaning. There is no clear data indicating that x amount of millisieverts per year is harmful. We know radioactivity clearly kills at high doses, but the effects of low doses are largely undetermined. And people fly all the time and take CT scans in hospitals without realizing that they get more radioactivity exposure this way.

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> There is no clear data indicating that x amount of millisieverts per year is harmful.

Radiation damage is a game of statistics: A single charged particle, electron (whatever) striking the right molecule in your body may be enough for you to develop cancer and die in a particularly nasty way. The chances of this singular event happening and at the same time all safeguard of your body failing are minuscule, though. But the more events you have (the higher the radiation), the higher the chances that it will happen. This is what we basically know about radiation: it damages cells and for some events the natural cleanup doesn't work. Basically you could say that every bit radiation is harmful, even the natural background radiation [1]. All guidelines and limits are based on the question whether the increased risk outweighs the possible gain. Early X-Rays had the problem of exposing the doctors to high doses, modern machines are designed with safety in mind. Still, patients and doctors wear protection when possible.

[1] to make matters worse, there's different kinds of radiation: alpha rad which doesn't even penetrate the skin, but is very harmful if dust is inhaled to high energy gamma rad that is basically impossible to shield without lead or other heavy metals around. So "1 millisievert" doesn't even tell you what it is, 1ms of alpha is probably better to handle than 1ms of gamma rad..

So how does that account for the supposed idea that people who live in Denver, who get 2x to 4x the average radiation than the normal population have far lower rates of cancer than average.

It can be explained by the concept of radiation hormesis. http://en.wikipedia.org/wiki/Radiation_hormesis

Like I already mentioned: radiation != radiation. A raw number in MS does not tell you anything at all. For a light treatment of the topic, see https://en.wikipedia.org/wiki/Banana_equivalent_dose

"The absorbed radiation dose depends on the type and energy of the emitted particles, as well as on the location of the source in the body (external, inhaled, ingested, etc.), and the biological half-life of the compounds ingested."

There are probably other controlling factors that come into play in Denver, so yes, that is still possible (if it is so, I'll add the wikipedia-style "citation needed").

> For a light treatment of the topic, see https://en.wikipedia.org/wiki/Banana_equivalent_dose

Please don't. The "banana equivalent dose" people make the wrong assumption that the excess potassium brought in the organism by eating a banana stays there for 50 years. Because of the way potassium homeostasis works, the excess is eliminated within a few hours, when urinating.

So let's reduce the average exposure time from 50 years to 12 hours and the radiation exposure from 0.078 microsievert to 0.00000213 microsievert. We're losing respect for some cool comic strip in the process[1], but the reality is worth it.

[1]: http://blog.xkcd.com/2011/03/19/radiation-chart/

> Please don't. The "banana equivalent dose" people make the wrong assumption that the excess potassium brought in the organism by eating a banana stays there for 50 years.

As you probably have noted, the BED has other problems as well, namely the source and kind of radiation is not taken into account - it's actually discussed in the wikipedia article. So reading the article is an enlightening skim on the surface if that's all you need ATM. There's no use in calculating your radiation exposure in BEDs - we both agree on that account.

Cite your source. This data suggests that you're wrong -- cancer rates are in line with national averages:

http://statecancerprofiles.cancer.gov/cgi-bin/ratetrendbycan...

Beyond that, it's like the parent said: you have to take into account the type of radiation, sources, method of exposure, etc.

Maybe because the background radiation is just one of many, many contributing causes of cancer?

For instance, airline pilots are exposed to more radiation than the average worker. But they also have a low percentage of smokers, and in order to keep their medical license they need to be in fairly good health. So, apart from skin cancer, they have lower than average rates of cancer compared to the general population:

https://www.alpa.org/portals/alpa/magazine/2001/March2001_He...

What do you propose is the lifestyle difference shared by the population of Denver that offsets their doubled exposure to low-level radiation?

Obviously cancer has many causes, but to the extent Denver shares those causes with Oregon, they should wash out and reveal Denver's radiation-linked cancer (which, after all, you're basically arguing exists).

I was just pointing out a flaw in his reasoning. I didn't argue that it exists (and from what I gather from other comments, it doesn't). But if it did, it could be offset by any number of things, some of which might not be shared to the same extent with other cities.

Or it might be that the baseline background radiation is so small that 2x that baseline is still statistically insignificant compared to other factors.

If you believe the latter statement, then you also aren't alarmed by radiation in Japan, right?

I don't believe anything in particular, that was just one of many potential explanations.

That said, I'm not alarmed by the radiation in Japan, I'm more alarmed about the situation of the Fukushima plant and the problems they face with potential leakage into the groundwater (among other things).

Exposure to mild stressors over extended periods of time enhances the robustness of the organism against that stressor (eg: vaccination, mild stressor here is the weakened disease agent). It's called Hormesis in general, and Radiation hormesis in your specific case - http://en.wikipedia.org/wiki/Radiation_hormesis

You're implying that accounting for the fact that people in Denver get "2x to 4x the average radiation" but "have far lower rates of cancer" is a problem for people who saying that small multiples of radiation exposure raise cancer risk, but ignoring that a lower incidence of cancer for Denver would have to be accounted for in any case, no matter what you believe about the relationship between radiation exposure and cancer.

Unless your actual argument here is that radiation prevents cancer - and I'd say that you have a higher burden of proof for that.

Denver is one of the most fit places in the US. Obesity is a major source of cancer. That or a million other such reasons.

Statements such as yours are exactly in vein with the the article and is exactly the type of BS pseudoscience used so commonly in the defense of nuclear power.

You're talking about the linear no-threshold model, which is used because it is conservative, but it is definitely not accepted as fact by the scientific community. Please don't present it as obvious or settled. There are good arguments that low doses are handled by the cell's mutation correction mechanisms in a way that cannot be done for high doses.

> One of the organizations for establishing recommendations on radiation protection guidelines internationally, the UNSCEAR, has recently recommended policies that do not agree with the Linear No-Threshold model at exposure levels below background levels of radiation to the UN General Assembly from the Fifty-Ninth Session of the Committee. Its recommendation states that "the Scientific Committee does not recommend multiplying very low doses by large numbers of individuals to estimate numbers of radiation-induced health effects within a population exposed to incremental doses at levels equivalent to or lower than natural background levels." This is a reversal from previous recommendations by the same organization.[2]

> Whether the model describes the reality for small-dose exposures is disputed. It opposes two competing schools of thought: the threshold model, which assumes that very small exposures are harmless, and the radiation hormesis model, which claims that radiation at very small doses can be beneficial. Because the current data are inconclusive, scientists disagree on which model should be used. Pending any definitive answer to these questions and the precautionary principle, the model is sometimes used to quantify the cancerous effect of collective doses of low-level radioactive contaminations, even though such practice has been condemned by the International Commission on Radiological Protection

https://en.wikipedia.org/wiki/Linear_no-threshold_model

>There are good arguments that low doses are handled by the cell's mutation correction mechanisms in a way that cannot be done for high doses.

Might be better to present those arguments, or links to those arguments. The argument that scientific opinion isn't settled, but there may be a magic number that has to be reached within a short period of time for exposure to be dangerous sounds like pro-nuclear FUD, whether it is or not.

I don't think the statement "There are good arguments that this is not harmful" could reasonably be described as "fear, uncertainty and doubt."

Speaking of CT scans, found this an interesting read on the topic:

"We Are Giving Ourselves Cancer"

"While it is difficult to know how many cancers will result from medical imaging, a 2009 study from the National Cancer Institute estimates that CT scans conducted in 2007 will cause a projected 29,000 excess cancer cases and 14,500 excess deaths over the lifetime of those exposed."

http://www.nytimes.com/2014/01/31/opinion/we-are-giving-ours...

This article was heavily debated on HN. Needless to say, these numbers should be considered with a big fat grain of salt.

It's overly dismissive to say it has no meaning. We know increases in radiation lead to increases in cancer 20-40 years out. We also know we can't design controlled experiments to properly measure risk (because of medical ethics), so we have to rely on epidemiological studies and animal testing, which have holes that well-funded carcinogen-producing industries can drive trucks through.

It's a difficult problem to balance risks of CT scan radiation against diagnostic value. Nobody wants to have to make that call. And CT scans are the tip of the iceberg. The easy answer for doctors is to simply ignore the risks of CT scans, since the legal system will back them up, but it won't back them up if they don't do a CT scan but the standard of care calls for a CT scan to diagnose a relatively minor or relatively unlikely problem.

related book: The Secret History of the War on Cancer by Devra Davis

We also know some levels of radiation may actually have protective effects (killing some viruses/bacteria which cause some cancers).

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