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I don't know much about medicine and radiation, but is intensity a factor? Could getting x amount of radiation in 60 seconds be a bigger danger than the same am

I don't know much about medicine and radiation, but is intensity a factor? Could getting x amount of radiation in 60 seconds be a bigger danger than the same amount of radiation spread out over days or months?

rosser 13y ago
Yes, it can, and often is. Consider Albert Stevens. [1] He was (without his knowledge or consent) injected with a dose of 131 kBq of Pu, yielding a lifetime exposure of around 64 Sv. (An acute dose of >= 5 Sv is usually fatal.) He died of heart disease 20 years later. [1] https://en.wikipedia.org/wiki/Albert_Stevens https://en.wikipedia.org/wiki/Albert_Stevens
beloch 13y ago
I'm not a doctor, but the way I understand it cumulative exposure is what really matters. Ionizing radiation, such as X-Rays, tends to pass through matter with less interaction than lower energy EMR, such as light. Obviously, there is some interaction or it wouldn't be good for imaging! When ionizing radiation is absorbed it (as the name suggests) ionizes an atom by knocking an electron free. That ion will then probably form a bond almost immediately, altering the molecule it's a part of. If that molecule is a cell-wall, piece of enamel on your teeth, etc. the change will be harmless. There's a small chance it could be change to the DNA of one of your cells though. Most changes are probably harmless, but some can cause the cell to replicate out of control. i.e. Cancer. Basically, getting cancer is like winning the lottery, and radiation gives you tickets. It doesn't matter if you get them all at once or spread them out. You might think radiation sickness is evidence that acute exposure behaves differently, but it actually takes several centuries worth of background radiation exposure to induce mild radiation sickness, so you're already operating in a whole new ballpark.
- jeffdavis 13y ago
  But your body constantly repairs, too, right? So maybe it's able to repair a few errors, but gets quickly overwhelmed during a CT scan?
  - aptwebapps 13y ago
    Your body repairs tissue tears and damaged cells as well as fighting off infections and things but I don't believe it is well-equipped to deal with damaged genes. I could be totally wrong, though.
    - chockablock 13y ago
      DNA repair is happening all the time -- this is a major benefit of having double-stranded DNA. Wikipedia offers DNA damage rates of 1e3 - 1e6 DNA damage events per cell, per day ( http://en.wikipedia.org/wiki/DNA_repair http://en.wikipedia.org/wiki/DNA_repair ). Almost all of these get repaired.
      - sitkack 13y ago
        Or they get terminated. We are all running on Erlang.
- cnvogel 13y ago
  Generally, the unit in which exposure to ionizing radiation is being measured is "Gray" (Gy) which is absorbed energy (Measured in Joules, equal to one Watt-Second) per kg of absorbing material. That's called the "Dose". If you account for the amount of damage that this Dose can do to humans, you'll call this weighted Dose "Sievert" (Sv). Generally the weighting is not that important for X-Rays or gamma-radiation (the "normal radioactivity" people are concerned about), but will be important when dealing with neutrons. The Wikipedia article on Sievert has a few examples: http://en.wikipedia.org/wiki/Sievert#Dose_examples http://en.wikipedia.org/wiki/Sievert#Dose_examples If a person is subjected to 5-10 Sv instantaneously, so many cells will be damaged that this person will die, not of cancer but of multiple organs ceasing to function properly over the course of a few days. But, as you already have written, that's about 2000 years of background radiation (3mSv/year) in a very short time (documented accidents: probably few or less than one second). -> http://en.wikipedia.org/wiki/Background_radiation http://en.wikipedia.org/wiki/Background_radiation There's data from survivors of the Hiroshima and Nagasaki bombs, and this data corresponds to exposure to about 50mSv to 2Sv. There are also other studies, including people living in areas with hither (or lower) natural radiation levels, working in former Soviet-Union closed-off nuclera-research areas, and so on... (http://www.nap.edu/openbook.php?record_id=11340 http://www.nap.edu/openbook.php?record_id=11340) All these "cohorts" (as they are called: a number of test subjects) have been studied for health effects. And a lot of people that got high doses died of cancer. Unfortunately everyone of us has a high high probability of getting cancer at some point in his life. And it turns out that you need a lot of radiation to double the risk of getting this disease: http://en.wikipedia.org/wiki/File:Increased_risk_with_dose.svg http://en.wikipedia.org/wiki/File:Increased_risk_with_dose.s... The straight line in this plot represents the "linear model" which assumes that the additional chance of getting malignant tumors rises just the same as the amount of radioactivity. But then, if you go down to the very-low-end, which is very, very, very difficult to analyze, because you are looking at only miniscule differences in cancer-rates, sometimes people find that it appears that a small amount of radiation might even be beneficial and reduce the risk of acquiring cancer in a lifetime. http://en.wikipedia.org/wiki/Radiation_hormesis http://en.wikipedia.org/wiki/Radiation_hormesis
deleted 13y ago
[deleted]

rosser 13y ago

Yes, it can, and often is. Consider Albert Stevens. [1] He was (without his knowledge or consent) injected with a dose of 131 kBq of Pu, yielding a lifetime exposure of around 64 Sv. (An acute dose of >= 5 Sv is usually fatal.) He died of heart disease 20 years later. [1] https://en.wikipedia.org/wiki/Albert_Stevens https://en.wikipedia.org/wiki/Albert_Stevens

beloch 13y ago

I'm not a doctor, but the way I understand it cumulative exposure is what really matters. Ionizing radiation, such as X-Rays, tends to pass through matter with less interaction than lower energy EMR, such as light. Obviously, there is some interaction or it wouldn't be good for imaging! When ionizing radiation is absorbed it (as the name suggests) ionizes an atom by knocking an electron free. That ion will then probably form a bond almost immediately, altering the molecule it's a part of. If that molecule is a cell-wall, piece of enamel on your teeth, etc. the change will be harmless. There's a small chance it could be change to the DNA of one of your cells though. Most changes are probably harmless, but some can cause the cell to replicate out of control. i.e. Cancer. Basically, getting cancer is like winning the lottery, and radiation gives you tickets. It doesn't matter if you get them all at once or spread them out. You might think radiation sickness is evidence that acute exposure behaves differently, but it actually takes several centuries worth of background radiation exposure to induce mild radiation sickness, so you're already operating in a whole new ballpark.

jeffdavis 13y ago
But your body constantly repairs, too, right? So maybe it's able to repair a few errors, but gets quickly overwhelmed during a CT scan?
- aptwebapps 13y ago
  Your body repairs tissue tears and damaged cells as well as fighting off infections and things but I don't believe it is well-equipped to deal with damaged genes. I could be totally wrong, though.
  - chockablock 13y ago
    DNA repair is happening all the time -- this is a major benefit of having double-stranded DNA. Wikipedia offers DNA damage rates of 1e3 - 1e6 DNA damage events per cell, per day ( http://en.wikipedia.org/wiki/DNA_repair http://en.wikipedia.org/wiki/DNA_repair ). Almost all of these get repaired.
    - sitkack 13y ago
      Or they get terminated. We are all running on Erlang.
cnvogel 13y ago
Generally, the unit in which exposure to ionizing radiation is being measured is "Gray" (Gy) which is absorbed energy (Measured in Joules, equal to one Watt-Second) per kg of absorbing material. That's called the "Dose". If you account for the amount of damage that this Dose can do to humans, you'll call this weighted Dose "Sievert" (Sv). Generally the weighting is not that important for X-Rays or gamma-radiation (the "normal radioactivity" people are concerned about), but will be important when dealing with neutrons. The Wikipedia article on Sievert has a few examples: http://en.wikipedia.org/wiki/Sievert#Dose_examples http://en.wikipedia.org/wiki/Sievert#Dose_examples If a person is subjected to 5-10 Sv instantaneously, so many cells will be damaged that this person will die, not of cancer but of multiple organs ceasing to function properly over the course of a few days. But, as you already have written, that's about 2000 years of background radiation (3mSv/year) in a very short time (documented accidents: probably few or less than one second). -> http://en.wikipedia.org/wiki/Background_radiation http://en.wikipedia.org/wiki/Background_radiation There's data from survivors of the Hiroshima and Nagasaki bombs, and this data corresponds to exposure to about 50mSv to 2Sv. There are also other studies, including people living in areas with hither (or lower) natural radiation levels, working in former Soviet-Union closed-off nuclera-research areas, and so on... (http://www.nap.edu/openbook.php?record_id=11340 http://www.nap.edu/openbook.php?record_id=11340) All these "cohorts" (as they are called: a number of test subjects) have been studied for health effects. And a lot of people that got high doses died of cancer. Unfortunately everyone of us has a high high probability of getting cancer at some point in his life. And it turns out that you need a lot of radiation to double the risk of getting this disease: http://en.wikipedia.org/wiki/File:Increased_risk_with_dose.svg http://en.wikipedia.org/wiki/File:Increased_risk_with_dose.s... The straight line in this plot represents the "linear model" which assumes that the additional chance of getting malignant tumors rises just the same as the amount of radioactivity. But then, if you go down to the very-low-end, which is very, very, very difficult to analyze, because you are looking at only miniscule differences in cancer-rates, sometimes people find that it appears that a small amount of radiation might even be beneficial and reduce the risk of acquiring cancer in a lifetime. http://en.wikipedia.org/wiki/Radiation_hormesis http://en.wikipedia.org/wiki/Radiation_hormesis

deleted 13y ago

[deleted]