The International Commission on Radiation Units and Measurements (ICRU) is a standardization body set up in 1925 by the International Congress of Radiology, originally as the X-Ray Unit Committee until 1950. Its objective "is to develop concepts, definitions and recommendations for the use of

quantities Quantity or amount is a property that can exist as a multitude or magnitude, which illustrate discontinuity and continuity. Quantities can be compared in terms of "more", "less", or "equal", or by assigning a numerical value multiple of a unit ...

and their

unit Unit may refer to: Arts and entertainment * UNIT, a fictional military organization in the science fiction television series ''Doctor Who'' * Unit of action, a discrete piece of action (or beat) in a theatrical presentation Music * ''Unit'' (alb ...

s for

ionizing radiation Ionizing radiation (or ionising radiation), including nuclear radiation, consists of subatomic particles or electromagnetic waves that have sufficient energy to ionize atoms or molecules by detaching electrons from them. Some particles can travel ...

and its interaction with matter, in particular with respect to the biological effects induced by radiation". The ICRU is a sister organisation to the

International Commission on Radiological Protection The International Commission on Radiological Protection (ICRP) is an independent, international, non-governmental organization, with the mission to protect people, animals, and the environment from the harmful effects of ionising radiation. Its r ...

(ICRP). In general terms the ICRU defines the units, and the ICRP recommends how they are used for

radiation protection Radiation protection, also known as radiological protection, is defined by the International Atomic Energy Agency (IAEA) as "The protection of people from harmful effects of exposure to ionizing radiation, and the means for achieving this". Expos ...

Development

During the first two decades of its existence, its formal meetings were held during the International Congress of Radiology, but from 1950 onwards, when its mandate was extended, it has met annually. Until 1953, the president of the ICRU was a national of the country that was hosting the ICR, but in that year it was decided to elect a permanent commission - the first permanent chairman being

Lauriston S. Taylor Lauriston S. Taylor (1 June 1902 – 26 November 2004) was an American physicist known for his work in the field of radiation protection and measurement. Career He established standards for X-ray radiation exposure for the first time in the 1920s, ...

who had been a member of the commission since 1928 and secretary since 1934. Taylor served until 1969 and on his retirement was accorded the position of honorary chairman which we held until his death in 2004, aged 102. In the late 1950s the ICRU was invited by the CGPM to join other scientific bodies to work with the

International Committee for Weights and Measures The General Conference on Weights and Measures (GCWM; french: Conférence générale des poids et mesures, CGPM) is the supreme authority of the International Bureau of Weights and Measures (BIPM), the intergovernmental organization established i ...

(CIPM) in the development of a system of units that could be used consistently over many disciplines. This body, initially known as the "Commission for the System of Units" (renamed in 1964 as the "Consultative Committee for Units") was responsible overseeing the development of the

International System of Units The International System of Units, known by the international abbreviation SI in all languages and sometimes pleonastically as the SI system, is the modern form of the metric system and the world's most widely used system of measurement. E ...

(SI). In the late 1950s the ICRU started publishing reports on an irregular basis - on average two to three a year. In 2001 the publication cycle was regularised and reports are now published bi-annually under the banner "Journal of the ICRU".

Current operation

The commission has a maximum of fifteen members who serve for four years and who, since 1950, have been nominated by the incumbent commissioners. Members are selected for their scientific ability and is widely regarded as the foremost panel of experts in radiation medicine and in the other fields of ICRU endeavor. The commission is funded by the sale of reports, by grants from the

European Commission The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body o ...

, the US National Cancer Institute and the

International Atomic Energy Agency The International Atomic Energy Agency (IAEA) is an intergovernmental organization that seeks to promote the peaceful use of nuclear energy and to inhibit its use for any military purpose, including nuclear weapons. It was established in 1957 ...

and indirectly by organisations and companies who provide meeting venues. Commissioners, many of whom have full-time university or research centre appointments, have their expenses reimbursed, but otherwise they receive no remuneration from the ICRU.

Radiation quantities

The commission has been responsible for defining and introducing many of the following units of measure. The number of different units for various quantities is indicative of changes of thinking in world metrology, especially the movement from cgs to SI units. The following table shows radiation quantities in SI and non-SI units. Although the United States Nuclear Regulatory Commission permits the use of the units

curie In computing, a CURIE (or ''Compact URI'') defines a generic, abbreviated syntax for expressing Uniform Resource Identifiers (URIs). It is an abbreviated URI expressed in a compact syntax, and may be found in both XML and non-XML grammars. A CURIE ...

, rad, and rem alongside SI units, the

European Union The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...

European units of measurement directives As of 2009, the European Union had issued two units of measurement directives: In 1971 it issued Directive 71/354/EEC which required EU member states to standardise on the International System of Units (SI) rather than use a variety of CGS ...

required that their use for "public health ... purposes" be phased out by 31 December 1985.

Administration

The Commission's secretariat is in Stockholm and its legal status is that of British

charity Charity may refer to: Giving * Charitable organization or charity, a non-profit organization whose primary objectives are philanthropy and social well-being of persons * Charity (practice), the practice of being benevolent, giving and sharing * Ch ...

(Not-for-profit organisation).

References

External links