Preliminary Research


Reference document: Radioactivity; Invisible Danger


Outline of Radiation


There are several types of radiation, such as α radiation, β radiation, γ rad iation and neutron radiation. We are constantly exposed to radiation in daily life . Radiation and radioactivity are completely different; radiation is waves such as p article beams and radioactivity is a substance which emits radiation. The units are as follows:



  • Sv…Unit to express radiation and the amount of radiation exposure
  • Bq……Unit to express radioactivity and the degree of contamination by radioactivity

    • There is natural and man-made radiation. Natural radiation is radiation such as cosmic rays which fall from space to the earth and radiation which is emitted from the ground, food and beverages. On the other hand, man-made radiation is radiation which is artificially made and used in industry and medical fields.



    Name UnitMeaning Example
    Amount of radiation exposure Coulomb (C/kg) Total amount of radiation emitted from a source of radiation About 5μC/kg per radiograph of the chest
    Absorbed dose Gray (Gy) Energy which is absorbed into the subject when radiation is emitted In the case above, the skin absorbs about 0.2mGy
    Equivalent dose
    Effective dose    		 Sievert Amount of radioactive isotope 0.05mSv for the case above
    Radioactivity Becquerel Amount of radioactive isotope Bone scintigram 99mTc Applied

    Units of Radiation

    Absorbed dose


  • The average value of energy deposited by radiation per unit mass of any physical matter.
  • 1Gy=1J/kg
  • Absorbed dose when 1J of energy is absorbed resulting from the interaction between radiation and 1kg of physical matter.

    • Equivalent Dose (Sv: Sievert)


  • Dose which expresses the radiation impacts on tissues and organs on a common scale after the differences in energy and type of radiation has been adjusted.
  • The average absorbed dose of tissues and organs (Gy) x Radiation weighting factor

    • Radiation in Daily Life


    Protons, electrons and X-ray etc which originate from the universe.
    　　　　　Natural Radiation in Our Body and Food.
    Amount of radiation in our body
    　　　　　Amount of Potassium-40 radiation in food

    Natural radiation material body, in food



  • (In the case of the Japanese 60kg body weight) the amount of radioactive material in the body
  • Radiation dose of potassium in the diet 40 (Japan)

    • Use a variety of radiation



  • (In the case of the Japanese 60kg body weight) the amount of radioactive material in the body
  • Radiation dose of potassium in the diet 40 (Japan)

    • Health effects of radiation


    What do you know in radiation measurement



  • The height of the radiation dose
  • Radiation source
    Type and energy of radiation emitted from the radiation source depends on the type of source.

    Type of radiation ray: α, line β, line γ, such as neutron

    • Radiation dose benchmark


    Half-life