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Japan Medicine

A Handy Radiation Dose Chart From XKCD 392

Posted by timothy
from the is-there-anything-xkcd-can't-do? dept.
An anonymous reader points out Randall Munroe's latest contribution to public health awareness, a "chart of how much ionizing radiation a person can absorb from various sources, compared visually. 1 Sievert will make you sick, many more will kill you, however, even small doses cumulatively increase cancer risk." It's a good way to think about the difference between Chernobyl and Fukushima.
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A Handy Radiation Dose Chart From XKCD

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  • DELICIOUS.

  • Bananas (Score:5, Informative)

    by mr100percent (57156) on Sunday March 20, 2011 @10:38AM (#35550182) Homepage Journal

    Fascinating, the mention of bananas was smart, since there's something known as Banana Equivalent Dose [wikipedia.org]

    • Re:Bananas (Score:5, Funny)

      by MrQuacker (1938262) on Sunday March 20, 2011 @10:45AM (#35550248)
      So, eating a banana is as radioactive as a threesome?
    • Re:Bananas (Score:5, Funny)

      by CharlyFoxtrot (1607527) on Sunday March 20, 2011 @11:06AM (#35550392)

      Wait, if God made bananas easy for humans to eat [youtube.com] and bananas are radioactive does that mean God's trying to kill us ?

      • Re:Bananas (Score:4, Funny)

        by gilleain (1310105) on Sunday March 20, 2011 @11:14AM (#35550454)

        Wait, if God made bananas easy for humans to eat [youtube.com] and bananas are radioactive does that mean God's trying to kill us ?

        No, it means that radiation is God's pure love. In order to get closer to Him, all the truly religious should get as close as possible to the hottest source they can find.

        WALK INTO THE LIGHT.

        (note : I am joking - I don't really want the faithful to die of radiation damage. I'm not Dawkins, ffs.)

        • Strangely, that's one of the fundamental precepts under the rather interesting SF book "The Karma Affair" by Arsen Darnay (that has to be a pseudonym). In it there was a rather intriguing way to handle nuclear waste involving the use of a dedicated priesthood, with some rather unusual side effects.
        • Re: (Score:3, Interesting)

          by AlejoHausner (1047558)

          radiation is God's pure love

          This idea exists in Greek myth: "[Semele] then demanded that Zeus reveal himself in all his glory as proof of his godhood. Though Zeus begged her not to ask this, she persisted and he was forced by his oath to comply. Zeus tried to spare her by showing her the smallest of his bolts and the sparsest thunderstorm clouds he could find. Mortals, however, cannot look upon Zeus without incinerating, and she perished, consumed in lightning-ignited flame" You should not ask the Godhead to reveal itself in its pure

      • Re:Bananas (Score:5, Insightful)

        by macslas'hole (1173441) on Sunday March 20, 2011 @05:43PM (#35553646)

        ... does that mean God's trying to kill us?

        What to you mean "trying"? Last I checked life was still a terminal affair and has been one for a long time.

    • Re:Bananas (Score:5, Insightful)

      by rtfa-troll (1340807) on Sunday March 20, 2011 @03:55PM (#35552726)

      Definitely a really nice chart. It's good to see something so easy to read and quantitative that helps people debate with some level of knowledge. The main problems for me with it are that it doesn't really do a good job on the time axis, spacial axes and the probabalistic risk. For example:

      • 50mSv absorbed in one year is probably completely safe. 50mSv absorbed in one second is quite likely to be bad, even if that's the only radiation absorbed in that whole year.
      • 50mSv spread through all issue types is likely no problem. Even though skin is normally considered less important in calculating Sieverts, 50mSv concentrated on a small area of skin can be a real problem .

      What makes this all difficult is that it seems the mechanisms are random. E.g. most of the time a particle of radiation does nothing. It dissociates a water molecule which soon after re-associates. Even if it does cause a mutation, that likely doesn't cause cancer because the body copes with mutation all the time and genetic codes self correct. However, if two or more mutations happen in close together / related genetic material in the same cell, that is reasonably likely to cause cancer as the cell is no longer able to self-correct. Now of course, this means that the "Lowest one-year dose clearly linked to increased cancer risk" is actually incorrect; that minimum ("clearly linked to increased", not to "noticeable") is about two particles of radiation where clearly is defined as "we clearly understand that this is so and "increased" is defined as "greater than would be otherwise. However, the minimum yearly dose "linked to a worrying increase according to a reasonable probabalistic model" is what we really want to know and is completely missing from the chart.

      Since the location of radiation damage is entirely random, that can mean that millions of particles could cause no damage to one person whilst just three could damage another very unlucky person. This risk gets higher the more concentrated in space and time a dose of radiation is. When you think about it, the reason is obvious. The chance of a repeat strike in the same cell goes up quadratically as the volume shrinks and factorially as the dosage increases. These are the crucial things which mean that radioactive iodine and back scatter scanners are likely to be much more dangerous than e.g. cosmic ray exposure at altitude or through body X-rays. They are also mean that having a back scatter X-ray just before or after travelling is (I have no idea exactly how much) worse than having the X-ray on its own.

      It would be really great if xkcd could do something which did a comparison of the dangers of different kinds of radiation exposure in different circumstances. Very important would be to leave in the ares of doubt where we actually don't know.

  • additional (Score:5, Informative)

    by toQDuj (806112) on Sunday March 20, 2011 @10:38AM (#35550184) Homepage Journal

    An additional useful chart can be found here, in a slightly more readable and intelligible format:
    http://eq.wide.ad.jp/files_en/110315houshasen_mext_en.pdf [wide.ad.jp]

    Not as all-inclusive as Randall's work, but still good.

  • Research (Score:5, Insightful)

    by Anonymous Coward on Sunday March 20, 2011 @10:52AM (#35550296)

    So what you are saying is that XKCD did more research and analysis for a web-comic than the 24 hour news networks do for a story?

  • Units (Score:5, Informative)

    by Chemisor (97276) on Sunday March 20, 2011 @11:02AM (#35550370)

    There are so many radiation units out there and people keep using them without regard to what they really mean. It's nice that you've got your Sieverts covered. Now you'll have to learn about Grays, Curies, Becquerels, Rads, Rems, and Roentgens. Here's a handy conversion chart. [stevequayle.com]

  • No (Score:2, Informative)

    by Anonymous Coward

    It's a good way to think about the difference between Chernobyl and Fukushima.

    No. It is not a good way to do that. It would have been if it had included measures like "Ten minutes next to the reactor core of Fukushima after partial meltdown" or "Dose from spending an hour on the grounds at the Fukushima plant in 2036". I'm not saying Fukushima is anywhere near as bad as Chernobyl, but if you want to compare them this chart is not what you need.

    • It would have been if it had included measures like "Ten minutes next to the reactor core of Fukushima after partial meltdown" or "Dose from spending an hour on the grounds at the Fukushima plant in 2036".

      It tried; it includes "Extra dose from one day in an average town near the Fukushima plant". Not the same as 10 minutes next to the core, but I guess Randall was using what he'd got.

    • by zill (1690130)

      "Ten minutes next to the reactor core of Fukushima after partial meltdown" or "Dose from spending an hour on the grounds at the Fukushima plant in 2036"

      I really don't see how you can come up with those figures, considering that 1. no one is standing next to the reactor core and 2. you can't predict the future.

  • by Dyinobal (1427207) on Sunday March 20, 2011 @11:06AM (#35550386)
    I found one source that said firefighters had radiation levels of 27 mSV after a 13 hour operation (presumably to cool down the reactor). Which doesn't seem to me to be a severe healthrisk after looking at the chart provided. Maybe I'm wrong but I'm vastly annoyed with the media, given how they talk you'd think people were losing their hair and growing skin lesions.
    • by ShakaUVM (157947) on Sunday March 20, 2011 @12:01PM (#35550928) Homepage Journal

      >>Maybe I'm wrong but I'm vastly annoyed with the media, given how they talk you'd think people were losing their hair and growing skin lesions.

      You're absolutely right to be annoyed at the media for getting it so wrong.

      But even the Slashdot summary is disingenuous:
      "1 Sievert will make you sick, many more will kill you, however, even small doses cumulatively increase cancer risk."

      There's no evidence for the LNT (linear no threshold) model for radiation exposure, other than people doing math and plotting a line down into the low-exposure ranges. All the epidemiological studies have shown much lower cancer incidence rates than the LNT would predict, indicating that there is a thresholding effect at work at low doses.

      This actually makes a *huge* difference when it comes to cleanup of radioactive material. Something like $200 billion worth of difference.

      That's why I'm interested in people actually, you know, testing this sort of stuff in the laboratory, like these guys: http://www.orionint.com/projects/ullre.cfm [orionint.com]

  • by Dunbal (464142) * on Sunday March 20, 2011 @11:08AM (#35550400)

    The Sievert is a measure of ACCUMULATED dose. Time is a factor. Therefore being exposed to 1 Sievert for a second (the real unit behind the sievert is the J/s, which is equivalent to Watts) is the same as being exposed to 1 milisievert for 1000 seconds, or 1 microsievert for 10^6 seconds.

    This is also why many measurements are done on a "per hour" basis. 400 milisieverts per hour (near the pool between reactors 3-4) is not harmful to you if you are going to be there for 5 minutes. If you stay there for 2.5 hours, however, you could experience signs of acute radiation sickness.

    I find it laughable, however, how the press a) fails to understand this and b) has obvious trouble converting between micro and mili.

    Finally one must bear in mind that radionuclides will decay over time (Iodine-131 being the main culprit here, has a half life of 8 days). So in 5 half lives (40 days), most of it will be gone. And also that the chronic health risk of radiation is usually overestimated, especially for such small doses as currently seen in Japan. It's statistical roulette, just like smoking. It just takes one cigarette to unleash the chain of events that will eventually lead to cancer. However the odds of it being the cigarette you are currently smoking are quite small. But if you smoke all your life, you're likely to buy the winning ticket eventually. The same with radiation. There are still living survivors of Hiroshima and Nagasaki, and these people were exposed to far more (and more harmful) radiation - gamma rays vs. beta particles. And yet not that many of them have "grown a third arm". Yes, there have been cancer deaths, but considering the population exposed, it wasn't all that much.

    • by selven (1556643) on Sunday March 20, 2011 @11:17AM (#35550480)

      (the real unit behind the sievert is the J/s, which is equivalent to Watts) is the same as being exposed to 1 milisievert for 1000 seconds

      True mathematically, but not medically [wikipedia.org]

      • by Dunbal (464142) * on Sunday March 20, 2011 @11:23AM (#35550528)
        Agreed. As a physician I am well aware that the body has compensation mechanisms for virtually everything, and they work fine so long as you don't overwhelm those mechanism (it usually always boils down to the rate of reaction of some enzyme or other). But was trying not to get too technical.
    • by nospam007 (722110) * on Sunday March 20, 2011 @11:24AM (#35550536)

      "However the odds of it being the cigarette you are currently smoking are quite small."

      "(Radioactive) Po-210 is also present in cigarettes. The actual mechanism by which the polonium arises in tobacco leaves is still disputed. It can arise through the decay of radon gas in the air directly onto the tobacco leaves or directly from the uptake of radioactive decay products of uranium in the earth in the roots of the plant. As cigarette burn, the radioactive polonium on the surface volatilizes and enter the lungs through inhalation. It has been claimed that radioactive polonium-210 is responsible for more than 90% of all smoking related lung cancers "

      http://www.nucleonica.net/wiki/index.php/Polonium_210 [nucleonica.net]

      • by Dunbal (464142) * on Sunday March 20, 2011 @11:28AM (#35550572)
        Yeah, forget about the other 200 or so carcinogens present in tobacco smoke. One article will not turn me into a believer. Especially since I think the dose of polonium could be considered homeopathic. I disagree until I see double blind clinically controlled trials that prove this. We never will, however, for ethical reasons.
    • by Nemyst (1383049)

      Most of the chart measurements have times given in the description (through the year, in a day, in an hour, etc.). The accumulated dose is still an interesting metric and the comparisons are valid as they give you an idea of how small/large a Sv actually is. 0.03387 uSv/hour wouldn't have the same impact as 17 mSv in a year (pulled numbers out of my hat here, not valid calculations).

      The measurements that do not have a time given are also very easy to determine (how long does it take for you to eat a banana?

    • by Anonymous Coward on Sunday March 20, 2011 @11:58AM (#35550894)

      the real unit behind the sievert is the J/s

      This is actually completely wrong. The Sievert is based on the Gray, which is defined in terms of J/kg. For a fixed mass, it's J, energy. It makes no sense to say "exposed to 1 Sievert for 1 second". You would have to say "exposed to 1 Sievert per second for 1 second".

    • by mspohr (589790)
      I think you are making a good point. There are two types of risks associated with radiation exposure. The first is what these charts address which is acute exposure leading to "radiation sickness". As the charts show, it take a relatively large dose of radiation to make you sick in the short term and most of the people in Japan (except the workers close to the plant) are receiving only small doses.

      The second risk is the long term risk of cancers. These show up years later and due to this delay in tim

    • by rkww (675767)

      the real unit behind the sievert is the J/s, which is equivalent to Watts

      No, it's a measure of energy absorbed - Joules per kilogram

      http://www.sizes.com/units/sievert.htm [sizes.com]

    • The Sievert is a measure of ACCUMULATED dose. Time is a factor. Therefore being exposed to 1 Sievert for a second (the real unit behind the sievert is the J/s, which is equivalent to Watts)....

      A point of clarification -- the gray (Gy) is technically the SI unit for absorbed dose, measured in joules per kilogram. The sievert (Sv) is a measure of dose equivalent, which takes the absorbed dose in Gy and multiplies it by a factor that accounts for the relative biological effect of the radiation. Whole-body doses of gamma radiation get a factor of 1; neutrons and alpha particles can have a factor of up to 20. Exposures to only part of the body have weighting factors less than 1; skin, which is par

  • by MadChicken (36468) on Sunday March 20, 2011 @11:08AM (#35550404) Homepage Journal

    This is not an incredibly informative measurement, it would be more useful to learn of the radiation levels in the evacuated areas (10km & 20km, last I heard) as well as the cautioned areas (30km, stay indoors).

  • Anyone acquainted with any of the literature in radiation exposure up through the late-1990s (including classic and still standard works like The Effects of Nuclear Weapons by Glasstone and Dolan) will have encountered discussion of radiation exposure in terms of rems, not sieverts. It is useful to know that a centisievert (cSv) is essentially identical with a rem, so expressing doses in cSv terms allows direct comparisons with the large body of older but still relevant literature.

    • by jgardia (985157)

      I think that is only with gamma radiation. for other types of radiation you have to apply a conversion factor, since sievert doesn't really measure energy, but damage to tissues. For alphas for example, the factor is 20.

    • by mbone (558574)

      I think you mean, the American literature. AFAIK, the Russian literature never used REMs at all, and some of it is in Becqurels and Curies.

      When the Soviet's opened up about Chernobyl they published readings in (IIRC) Becquerels or Becquerels/m^3, causing intense puzzlement in the Western press as to how to interpret what they were saying.

  • by FauxReal (653820) on Sunday March 20, 2011 @11:21AM (#35550506) Homepage

    I would like to have seen the dosage given by using the backscatter machine at an airport listed.

    • by Manip (656104)
      0.09 Sv, slightly less than one banana.
      • Re: (Score:2, Funny)

        by Anonymous Coward
        I think you meant 0.09 uSv, unless your bananas grow inside nuclear reactor
    • by Lehk228 (705449) on Sunday March 20, 2011 @12:37PM (#35551222) Journal
      Given how honest the TSA has been about them, probably close to the same as vacationing for a week at chernobyl
    • by Khopesh (112447) on Sunday March 20, 2011 @03:37PM (#35552556) Homepage Journal

      I was surprised to see the TSA's full-body screening systems didn't make the list ... until I saw the reports of how much radiation it exposes us to. I'm using data from NPR's Scientists Question Safety Of New Airport Scanners [npr.org] (2010-05-17) and TSA's X-ray Screening Technology Safety Reports [tsa.gov] (date unknown, cited on the TSA Blog [tsa.gov] 2011-03-12).

      Note, to compare with XKCD's chart, both TSA and NPR state that a standard chest x-ray is 100 uSv rather than this XKCD's 20 uSv. NPR puts a mammogram at 700 uSv while XKCD holds it as 3000 uSv.

      The stated radiation from these backscatter scanners is 0.05 uSv (TSA, reported as 0.005 mrem [wikipedia.org]) to 0.2 uSv (UCSF via NPR) per usage. UCSF suggests that measuring this radiation on the skin would result in a larger value. The TSA report includes a disclaimer that they are re-testing these numbers and should have results around the end of this month. Another post here noted 0.09 uSv but had no source (reported as "0.09 Sv" because Slashdot eats the Greek letter mu).

      The real danger with respect to the backscatter scanners was to the TSA workers (who had zero protection) and others who work in airports. The NPR piece also cites David Brenner, head of Columbia University's Center for Radiological Research, saying that 5% of the population is especially sensitive to radiation and that "we don't really have a quick and easy test to find those individuals." Fortunately, these machines are not in use any more, though that might change if the TSA's new report doesn't increase those numbers (or it gets trumped by fearmongering on behalf of some news outlet or politician).

  • Comparison between the exposure of an aid worker who flew from the US / EU to Japan and right back again, and what he would have accumulated in a week saving people 100 miles away from Fukushima.
  • 1 Sievert? What is that in feet?

  • by Alwinner (1576143) on Sunday March 20, 2011 @11:33AM (#35550624) Homepage
    Coal fired powers stations emit more radioactivity than nuclear power stations and also release greenhouse gases and ash. We should be shutting all of these as soon as possible to protect the Earth and its people. The deaths due to coal mining annually exceed all deaths in over fifty years of nuclear power generation.
  • A number line would have done so much more.
    The thing that very few people are mentioning is:

    The exposure occurring over the days and weeks.
    Not everyone has an x-ray every day.

    The Japanese ministry is suppressing both the radiation figures for Fukushima and the areal photos recently taken.

    The atom is an amazing thing because it makes people lie so much?

  • Will I gain super powers if I visit the reactor?

  • by Gorimek (61128) on Sunday March 20, 2011 @12:34PM (#35551196) Homepage

    I think one major cause of nucleophobia is that doses of a millionth of anything dangerous or less are easily measurable

    Negligible doses of most every poison is always around, but are unmeasurable. Radiation radiates its presence and is observed, reported and terrifying.

    • by Hooya (518216)

      I think one major cause of nucleophobia is that doses of a millionth of anything dangerous or less are easily measurable

      Negligible doses of most every poison is always around, but are unmeasurable. Radiation radiates its presence and is observed, reported and terrifying.

      I was talking about this with a co-worker who is from Ukraine. From near Kiev. We came to the conclusion that the nucleophobia is more from the reality that you really get no physical stimulus to tell you something is harming you until it's too late. Like the poison example you used. I have centuries of evolutionary logic programmed into me to, first, decide if something "looks" poisonous. Case in point, get some organic potatoes and you'll feel like chucking the purple ones. You know not to eat any random

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