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:

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.
Additional restrictions apply to the occupational exposure of pregnant women.
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.
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:

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.
For area of skin averaged over any 1 cm².

For detail information, please refer to Radiation Ordinance (Chapter 303) in the Laws of Hong Kong.

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