gamma ray~

Why would the gamma ray be dangerous in our body?

(Please answer in atom side.)

1 個解答

  • 1 十年前

    The gamma rays are the most dangerous form of radiation emitted by a nuclear explosion because of the difficulty in stopping them. Gamma-rays are not stopped by the skin.

    They can induce DNA alteration by interfering with the genetic material of the cell. DNA double-strand breaks are generally accepted to be the most biologically significant lesion by which ionizing radiation causes cancer and hereditary disease.

    A study done on Russian nuclear workers exposed to external whole-body gamma radiation at high cumulative doses shows the link between radiation exposure and death from leukemia, lung, liver, skeletal and other solid cancers.

    Alongside radiation, gamma-rays also produce thermal burn injuries and induce an immunosuppressive effect.

    After gamma-irradiation, and the breaking of the DNA double-strands, the cell can repair the damaged genetic material in the limit of its capability.

    However, a study of Rothkamm and Lobrich has shown that the repairing works well after high-dose exposure but is much slower in the case of a low-dose exposure.

    It could mean that a chronic low-dose exposure could not be fought by the body.

    The natural outdoor exposition in Great Britain is in the range 20-40 nSv/h. Natural exposition to gamma rays is about 1 to 2 mSv a year, and the average total amount of radiation received in one year per inhabitant in USA is 3,6 mSv.

    By comparison, the radiation dose from chest radiography is a fraction of the annual naturally occurring background radiation dose, and the dose from fluoroscopy of the stomach is, at most, 0.05 Sv on the skin of the back.

    For acute full-body equivalent dose, 1 Sv causes slight blood changes, 2-5 Sv causes nausea, hair loss, hemorrhaging and will cause death in many cases. More than 3 Sv will lead to death in less than two months in more than 80% of cases, and much over 4 Sv is more likely than not to cause death.

    For low dose exposure, for example among nuclear workers, who receive an average radiation dose of 19mSv, the risk of dying from cancer (excluding leukemia) increases by 2 percent. For a dose of 100mSv, that risk increase is at 10 percent. By comparison, it was 32% for the Atom Bomb survivors.