Dose limits

Dose limits are recommended by the International Commission on Radiological Protection (ICRP). They are in place to ensure that individuals are not exposed to an unnecessarily high amount of ionizing radiation. Dose limits are a fundamental component of radiation protection, and breaching these limits is against radiation regulation in most countries.

The limits are split into two groups, the public, and occupationally-exposed workers. The following limits are up to date at the time of writing this article (April 2017) ^1,2.

Occupationally exposed workers

• effective dose
  • 20 mSv a year, averaged over defined periods of 5 years with no single year >50 mSv
• the equivalent dose to the lens of the eye
  • 20 mSv a year, averaged over defined periods of 5 years with no single year >50 mSv ² (this was previously 150 mSv a year and updated in 2013)
• the equivalent dose to the skin (averaged over 1 cm²)
  • 500 mSv in a year
• the equivalent dose to the hands and feet
  • 500 mSv in a year

The ICRP recommends that occupational exposure of pregnant women should fall into the limits similar to that of the public.

Public

• effective dose
  • 1 mSv a year (higher values are permitted if the average over 5 years is not above 1 mSv a year)
• the equivalent dose to the lens of the eye
  • 15 mSv a year
• the equivalent dose to the skin (averaged over 1 cm²)
  • 50 mSv a year

Dose limits do not apply to medical exposures; however, the concept of radiation protection is still pertinent.