• Question: What's the most radiation a body can take?

    Asked by anon-197431 to Sonal, Rosanna, Matthew, Marleen, Dan on 13 Mar 2019.
    • Photo: Dan Porter

      Dan Porter answered on 13 Mar 2019:

      The amount of radiation a body can take is very dependent on the type radiation and how it is absorbed – for instance alpha radiation (charged He ions) is absorbed very strongly by tissue so is very dangerous if you eat something that emits alpha particles, but most of the time the skin is thick enough to stop it entering the body. Gamma radiation (high energy photons) by comparison is not absorbed strongly by the body but it is very difficult to shield against.

      We have a scientific unit called the Sievert which we use to measure the amount of radiation absorbed by the body and is normalised for the different types of radiation. 1 Sv = 1 joule of energy absorbed by 1 kg of biological mass. If you fly on a plane you are given a few mSv ~ 0.005 Sv. Most people who work with radiation have to keep their exposure to less than 50 mSv per year.

      If a person was unlucky enough to receive a dose of 1 Sv, that would give you an chance of around 5% of getting cancer on the spot. Taking a dose of 5 Sv would likely kill in a matter of months and 10 Sv would kill the person in a few weeks.

    • Photo: Matthew Selwood

      Matthew Selwood answered on 13 Mar 2019:

      I had absolutely no idea about this, so I have done some research. So there, is a unit of radiation unit called REM (Roentgen Equivalent for Man), which I can only assume is benchmarked on Roentgen radiation, like a mole is benchmarked on Carbon-12. According to this blog (link at the bottom), 500 REM is enough to kill you, and 2,000 REM is enough to ensure you get cancer – although yes, you will definitely be dead at that point! To be sick from radiation is apparently 25 REM.

      To put it into perspective, an x-ray at the dentist is 0.04 REM, so it would take one hell of a lot of x-rays! Like most things, it is a constant exposure to high levels of radiation which is more harmful than a 1 off. Hope this answers your question!

      Article: https://blogs.agu.org/wildwildscience/2009/09/01/how-much-radiation-does-it-take-to-kill-you/

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