Abbreviation | ICRP |
---|---|
Formation | 1928 |
Type | INGO |
Location | |
Region served | Worldwide |
Official language | English |
Website | ICRP Official website |
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 recommendations form the basis of radiological protection policy, regulations, guidelines and practice worldwide.
The ICRP was effectively founded in 1928 at the second International Congress of Radiology in Stockholm, Sweden but was then called the International X-ray and Radium Protection Committee (IXRPC). [1] In 1950 it was restructured to take account of new uses of radiation outside the medical area and re-named as the ICRP.
The ICRP is a sister organisation to the International Commission on Radiation Units and Measurements (ICRU). In general terms ICRU defines the units, and ICRP recommends, develops and maintains the International system of radiological protection which uses these units.
The ICRP is a not-for-profit organization registered as a charity in the United Kingdom and has its scientific secretariat in Ottawa, Ontario, Canada.
It is an independent, international organization with more than two hundred volunteer members from approximately thirty countries on six continents, who represent the world's leading scientists and policy makers in the field of radiological protection.
The International System of Radiological Protection has been developed by ICRP based on the current understanding of the science of radiation exposures and effects, and value judgements. These value judgements take into account societal expectations, ethics, and experience gained in application of the system. [2]
The work of the Commission centres on the operation of four main committees: [3]
Supporting these committees are Task Groups, established primarily to develop ICRP publications.
The ICRP's key output is the production of regular publications disseminating information and recommendations through the "Annals of the ICRP". [4]
These have become one of the main means of communicating advances by the ICRP in the form of technical presentations and reports from various committees drawn from the international radiological protection community. They have been held every two years since 2011. [5]
A year after Röntgen's discovery of X-rays in 1895, the American engineer Wolfram Fuchs gave what was probably the first radiation protection advice, but many early users of X-rays were initially unaware of the hazards and protection was rudimentary or non-existent. [11]
The dangers of radioactivity and radiation were not immediately recognized. The discovery of X‑rays had led to widespread experimentation by scientists, physicians, and inventors, but many people began recounting stories of burns, hair loss and worse in technical journals as early as 1896. In February 1896 Professor Daniel and Dr. Dudley of Vanderbilt University performed an experiment involving X-raying Dudley's head that resulted in his hair loss. A report by Dr. H.D. Hawks, a graduate of Columbia College, of his suffering severe hand and chest burns in an x-ray demonstration, was the first of many other reports in Electrical Review. [12]
Many experimenters including Elihu Thomson at Thomas Edison's lab, William J. Morton, and Nikola Tesla also reported burns. Elihu Thomson deliberately exposed a finger to an X-ray tube over a period of time and suffered pain, swelling, and blistering. [13] Other effects, including ultraviolet rays and ozone were sometimes blamed for the damage. [14] Many physicians claimed that there were no effects from X-ray exposure at all. [13]
Wide acceptance of ionizing radiation hazards was slow to emerge, and it was not until 1925 that the establishment of international radiological protection standards was discussed at the first International Congress of Radiology (ICR).
The second ICR was held in Stockholm in 1928 and the ICRU proposed the adoption of the roentgen unit; and the 'International X-ray and Radium Protection Committee' (IXRPC) was formed. Rolf Sievert was named Chairman, and a driving force was George Kaye of the British National Physical Laboratory. [1]
The committee met for just a day at each of the ICR meetings in Paris in 1931, Zurich in 1934, and Chicago in 1937. At the 1934 meeting in Zurich, the Commission was faced with undue membership interference. The hosts insisted on having four Swiss participants (out of a total of 11 members), and the German authorities replaced the Jewish German member with another of their choice. In response to this, the Commission decided on new rules in order to establish full control over its future membership. [1]
After World War II the increased range and quantity of radioactive substances being handled as a result of military and civil nuclear programmes led to large additional groups of occupational workers and the public being potentially exposed to harmful levels of ionising radiation. [1]
Against this background, the first post-war ICR convened in London in 1950, but only two IXRPC members were still active from pre-war days; Lauriston Taylor and Rolf Sievert. Taylor was invited to revive and revise the IXRPC, which included renaming it as the International Commission on Radiological Protection (ICRP). Sievert remained an active member, Sir Ernest Rock Carling (UK) was appointed as Chairman, and Walter Binks (UK) took over as Scientific Secretary because of Taylor's concurrent involvement with the sister organisation, ICRU. [1]
At that meeting, six sub-committees were established: [1]
The next meeting was in 1956 in Geneva. This was the first time that a formal meeting of the Commission took place independently of the ICR. At this meeting, ICRP became formally affiliated with the World Health Organization (WHO) as a 'participating non-governmental organisation'. [15]
In 1959, a formal relationship was established with the International Atomic Energy Agency (IAEA), and subsequently with UNSCEAR, the International Labour Office (ILO), the Food and Agriculture Organization (FAO), the International Organization for Standardization (ISO), and UNESCO.
At the meeting in Stockholm in May 1962, the Commission also decided to reorganise the committee system in order to improve productivity and four committees were created:
After many assessments of committee roles within an environment of increasing workloads and changes in societal emphasis, by 2008 the committee structure had become: [1]
The key output of the ICRP and its historic predecessor has been the issuing of recommendations in the form of reports and publications. The contents are made available for adoption by national regulatory bodies to the extent that they wish.
Early recommendations were general guides on exposure and thereby dose limits, and it was not until the nuclear era that a greater degree of sophistication was required.
In the "1951 Recommendations" the commission recommended a maximum permissible dose of 0.5 roentgen (0.0044 grays) in any 1 week in the case of whole-body exposure to X and gamma radiation at the surface, and 1.5 roentgen (0.013 grays) in any 1 week in the case of exposure of hands and forearms. [1] Maximum permissible body burdens were given for 11 nuclides. At this time it was first stated that the purpose of radiological protection was that of avoiding deterministic effects from occupational exposures, and the principle of radiological protection was to keep individuals below the relevant thresholds.
A first recommendation on restrictions of exposures of members of the general public appeared in the commission's part of the 1954 Recommendations. It was also stated that 'since no radiation level higher than the natural background can be regarded as absolutely "safe", the problem is to choose a practical level that, in the light of present knowledge, involves a negligible risk'. However, the Commission had not rejected the possibility of a threshold for stochastic effects. At this time the rad and rem were introduced for absorbed dose and RBE-weighted dose respectively.
At its 1956 meeting the concept of a controlled area and radiation safety officer were introduced, and the first specific advice was given for pregnant women.
In 1957, there was pressure on ICRP from both the World Health Organisation and UNSCEAR to reveal all of the decisions from its 1956 meeting in Geneva. The final document, the Commission's 1958 Recommendations was the first ICRP report published by Pergamon Press. The 1958 Recommendations are usually referred to as 'Publication 1'. [17]
The significance of stochastic effects began to influence the commission's policy and a new set of recommendations was published as Publication 9 in 1966. However, during development its editors became concerned about the many different opinions on the risk of stochastic effects. The Commission therefore asked a working group to consider these, and their report, Publication 8 (1966), for the first time for the ICRP summarised the current knowledge about radiation risks, both somatic and genetic. Publication 9 then followed, and substantially changed radiation protection emphasis by moving from deterministic to stochastic effects.
In October 1974, the official definition of Reference man was adopted by the ICRP: “Reference man is defined as being between 20-30 years of age, weighing 70 kg, is 170 cm in height, and lives in a climate with an average temperature of from 10 to 20 degrees C. He is a Caucasian and is a Western European or North American in habitat and custom.” [18] The reference man is created for the estimation of radiation doses without adverse health effects.
In 1977 Publication 26 set out the new system of dose limitation and introduced the three principles of protection: [1]
These principles have since become known as justification, optimisation (as low as reasonably achievable), and the application of dose limits. The optimisation principle was introduced because of the need to find some way of balancing costs and benefits of the introduction of a radiation source involving ionising radiation or radionuclides. [1]
The 1977 Recommendations were very concerned with the ethical basis of how to decide what is reasonably achievable in dose reduction. The principle of justification aims to do more good than harm, and that of optimisation aims to maximise the margin of good over harm for society as a whole. They therefore satisfy the utilitarian ethical principle proposed primarily by Jeremy Bentham and John Stuart Mill. Utilitarians judge actions by their overall consequences, usually by comparing, in monetary terms, the relevant benefits obtained by a particular protective measure with the net cost of introducing that measure. On the other hand, the principle of applying dose limits aims to protect the rights of the individual not to be exposed to an excessive level of harm, even if this could cause great problems for society at large. This principle therefore satisfies the Deontological principle of ethics, proposed primarily by Immanuel Kant. [1]
Consequently, the concept of the collective dose was introduced to facilitate cost–benefit analysis and to restrict the uncontrolled build-up of exposure to long-lived radio nuclides in the environment. [19] With the global expansion of nuclear reactors and reprocessing it was feared global doses could again reach the levels seen from atmospheric testing of nuclear weapons. So, by 1977, the establishment of dose limits was secondary to the establishment of cost–benefit analysis and use of collective dose. [1]
During the 1980s, there were re-evaluations of the survivors of the atomic bombings of Hiroshima and Nagasaki, partly due to revisions in the dosimetry. The risks of exposure were claimed to be higher than those used by ICRP, and pressures began to appear for a reduction in dose limits. [20]
By 1989, the commission had itself revised upwards its estimates of the risks of carcinogenesis from exposure to ionising radiation. The following year, it adopted its 1990 Recommendations for a 'system of radiological protection'. The principles of protection recommended by the Commission were still based on the general principles given in Publication 26. However, there were important additions which weakened the link to cost benefit analysis and collective dose, and strengthened the protection of the individual, which reflected changes in societal values:
In the 21st century, the latest overall recommendations on an international system of radiological protection appeared. ICRP Publication 103 (2007), after two phases of international public consultation, has resulted in more continuity than change. Some recommendations remain because they work and are clear, others have been updated because understanding has evolved, some items have been added because there has been a void, and some concepts are better explained because more guidance is needed. [16]
In collaboration with the ICRU, the commission has assisted in defining the use of many of the dose quantities in the accompanying diagram.
The table below shows the number of different units for various quantities and is indicative of changes of thinking in world metrology, especially the movement from cgs to SI units. [21]
Quantity | Unit | Symbol | Derivation | Year | SI equivalent |
---|---|---|---|---|---|
Activity (A) | becquerel | Bq | s−1 | 1974 | SI unit |
curie | Ci | 3.7×1010 s−1 | 1953 | 3.7×1010 Bq | |
rutherford | Rd | 106 s−1 | 1946 | 1000000 Bq | |
Exposure (X) | coulomb per kilogram | C/kg | C⋅kg−1 of air | 1974 | SI unit |
röntgen | R | esu / 0.001293 g of air | 1928 | 2.58×10−4 C/kg | |
Absorbed dose (D) | gray | Gy | J⋅kg−1 | 1974 | SI unit |
erg per gram | erg/g | erg⋅g−1 | 1950 | 1.0×10−4 Gy | |
rad | rad | 100 erg⋅g−1 | 1953 | 0.010 Gy | |
Equivalent dose (H) | sievert | Sv | J⋅kg−1 × WR | 1977 | SI unit |
röntgen equivalent man | rem | 100 erg⋅g−1 × WR | 1971 | 0.010 Sv | |
Effective dose (E) | sievert | Sv | J⋅kg−1 × WR × WT | 1977 | SI unit |
röntgen equivalent man | rem | 100 erg⋅g−1 × WR × WT | 1971 | 0.010 Sv |
Although the United States Nuclear Regulatory Commission permits the use of the units curie, rad, and rem alongside SI units, [22] the European Union European units of measurement directives required that their use for "public health ... purposes" be phased out by 31 December 1985. [23]
ICRP issues two awards the Bo Lindell Medal which is awarded annually and the Gold Medal for Radiation Protection which is issued every four years since 1962. [24]
The recipients of the gold medal for Radiation Protection are listed below:
The recipients of the Bo Lindell Medal for the Promotion of Radiological Protection are listed below:
The sievert is a unit in the International System of Units (SI) intended to represent the stochastic health risk of ionizing radiation, which is defined as the probability of causing radiation-induced cancer and genetic damage. The sievert is important in dosimetry and radiation protection. It is named after Rolf Maximilian Sievert, a Swedish medical physicist renowned for work on radiation dose measurement and research into the biological effects of radiation.
Ionizing 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 up to 99% of the speed of light, and the electromagnetic waves are on the high-energy portion of the electromagnetic spectrum.
The gray is the unit of ionizing radiation dose in the International System of Units (SI), defined as the absorption of one joule of radiation energy per kilogram of matter.
Radiation dosimetry in the fields of health physics and radiation protection is the measurement, calculation and assessment of the ionizing radiation dose absorbed by an object, usually the human body. This applies both internally, due to ingested or inhaled radioactive substances, or externally due to irradiation by sources of radiation.
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". Exposure can be from a source of radiation external to the human body or due to internal irradiation caused by the ingestion of radioactive contamination.
Equivalent dose is a dose quantity H representing the stochastic health effects of low levels of ionizing radiation on the human body which represents the probability of radiation-induced cancer and genetic damage. It is derived from the physical quantity absorbed dose, but also takes into account the biological effectiveness of the radiation, which is dependent on the radiation type and energy. In the SI system of units, the unit of measure is the sievert (Sv).
Health physics, also referred to as the science of radiation protection, is the profession devoted to protecting people and their environment from potential radiation hazards, while making it possible to enjoy the beneficial uses of radiation. Health physicists normally require a four-year bachelor’s degree and qualifying experience that demonstrates a professional knowledge of the theory and application of radiation protection principles and closely related sciences. Health physicists principally work at facilities where radionuclides or other sources of ionizing radiation are used or produced; these include research, industry, education, medical facilities, nuclear power, military, environmental protection, enforcement of government regulations, and decontamination and decommissioning—the combination of education and experience for health physicists depends on the specific field in which the health physicist is engaged.
The roentgen equivalent man (rem) is a CGS unit of equivalent dose, effective dose, and committed dose, which are dose measures used to estimate potential health effects of low levels of ionizing radiation on the human body.
Absorbed dose is a dose quantity which is the measure of the energy deposited in matter by ionizing radiation per unit mass. Absorbed dose is used in the calculation of dose uptake in living tissue in both radiation protection, and radiology. It is also used to directly compare the effect of radiation on inanimate matter such as in radiation hardening.
The linear no-threshold model (LNT) is a dose-response model used in radiation protection to estimate stochastic health effects such as radiation-induced cancer, genetic mutations and teratogenic effects on the human body due to exposure to ionizing radiation. The model assumes a linear relationship between dose and health effects, even for very low doses where biological effects are more difficult to observe. The LNT model implies that all exposure to ionizing radiation is harmful, regardless of how low the dose is, and that the effect is cumulative over lifetime.
Rolf Maximilian Sievert was a Swedish medical physicist whose major contribution was in the study of the biological effects of ionizing radiation.
The rad is a unit of absorbed radiation dose, defined as 1 rad = 0.01 Gy = 0.01 J/kg. It was originally defined in CGS units in 1953 as the dose causing 100 ergs of energy to be absorbed by one gram of matter. The material absorbing the radiation can be human tissue, air, water, or any other substance.
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 and their units for ionizing radiation and its interaction with matter, in particular with respect to the biological effects induced by radiation".
Radiobiology is a field of clinical and basic medical sciences that involves the study of the effects of ionizing radiation on living things, in particular health effects of radiation. Ionizing radiation is generally harmful and potentially lethal to living things but can have health benefits in radiation therapy for the treatment of cancer and thyrotoxicosis. Its most common impact is the induction of cancer with a latent period of years or decades after exposure. High doses can cause visually dramatic radiation burns, and/or rapid fatality through acute radiation syndrome. Controlled doses are used for medical imaging and radiotherapy.
In radiobiology, the relative biological effectiveness is the ratio of biological effectiveness of one type of ionizing radiation relative to another, given the same amount of absorbed energy. The RBE is an empirical value that varies depending on the type of ionizing radiation, the energies involved, the biological effects being considered such as cell death, and the oxygen tension of the tissues or so-called oxygen effect.
The roentgen or röntgen is a legacy unit of measurement for the exposure of X-rays and gamma rays, and is defined as the electric charge freed by such radiation in a specified volume of air divided by the mass of that air . In 1928, it was adopted as the first international measurement quantity for ionizing radiation to be defined for radiation protection, as it was then the most easily replicated method of measuring air ionization by using ion chambers. It is named after the German physicist Wilhelm Röntgen, who discovered X-rays and was awarded the first Nobel Prize in Physics for the discovery.
Effective dose is a dose quantity in the International Commission on Radiological Protection (ICRP) system of radiological protection.
The committed dose in radiological protection is a measure of the stochastic health risk due to an intake of radioactive material into the human body. Stochastic in this context is defined as the probability of cancer induction and genetic damage, due to low levels of radiation. The SI unit of measure is the sievert.
The International Congress of Radiology (ICR) is a meeting of radiologists for the exchange of ideas and the harmonisation of international standards and practice, first held in 1925 in London and held at regular intervals since then. Since 1994 it has become a biennial event. Until 1953 each congress was organised by radiological society of the host country, but in that year, a formal organisation, the International Society for Radiology was set up to provide continuity between the congresses.
Flight-time equivalent dose (FED) is an informal unit of measurement of ionizing radiation exposure. Expressed in units of flight-time, one unit of flight-time is approximately equivalent to the radiological dose received during the same unit of time spent in an airliner at cruising altitude. FED is intended as a general educational unit to enable a better understanding of radiological dose by converting dose typically presented in sieverts into units of time. FED is only meant as an educational exercise and is not a formally adopted dose measurement.
As of 10 May 2017, this article is derived in whole or in part from ICRP . The copyright holder has licensed the content in a manner that permits reuse under CC BY-SA 3.0 and GFDL. All relevant terms must be followed.