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    Dose limits

    International standard

    In the 2007 Recommendations of the International Commission on Radiological Protection (ICRP Publication No. 103), the recommended dose limits for exposure associated with practice are as follows:

    Dose limits1
    Application Persons employed in radiation work Public
    Effective dose
    Whole body

    20 mSv per year, averaged over defined periods of 5 years

    Not exceed 50 mSv in any single year2

    		 1 mSv per year3
    Annual equivalent dose in
    the lens of the eye

    20 mSv per year, averaged over defined periods of 5 years

    Not exceed 50 mSv in any single year

    		 15 mSv
    the skin4 500 mSv 50 mSv
    the hands and feet 500 mSv -

    Note:

    1. The limits apply to the sum of the relevant doses from external exposure in the specified period and the 50-year committed dose (to age 70 years for children) from intakes in the same period.
    2. Additional restrictions apply to the occupational exposure of pregnant women.
    3. In special circumstances, a higher value of effective dose could be allowed in a single year, provided that the average over 5 years does not exceed 1 mSv per year.
    4. The limitation on the effective dose provides sufficient protection for the skin against stochastic effects. An additional limit is needed for localized exposures in order to prevent deterministic effects.

    Standards in Hong Kong

    Dose limits stipulated in the Laws of Hong Kong are as follows:

    Dose limits (Hong Kong)
    Application Persons employed in radiation work Public
    Effective dose
    Whole body

    20 mSv per year1

    		 1 mSv per year
    Annual equivalent dose in
    the lens of the eye 150 mSv -
    the skin2 500 mSv -
    the hands and feet 500 mSv -

    Note:

    1. In the case of the abdomen of a woman with reproductive capacity, 5 mSv in any consecutive 3 months interval; and in the case of a pregnant woman, 1 mSv to the fetus during the pregnancy of the woman.
    2. For area of skin averaged over any 1 cm².

    For detail information, please refer to This link will open in a new windowRadiation Ordinance (Chapter 303) in the Laws of Hong Kong.

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