ICRPaedia - User contributions [en]

Effective dose equivalent

2026-09-10T00:58:24Z

Charlotte White:

The tissue weighted sum of dose equivalent to an organ or tissue from all specified organs and tissues of the body, given by the expression

<div style='text-align: center;'>
<math>
H_\text{E} = \displaystyle \sum_{\text{T}} w_\text{T}H_\text{T}
</math>
</div>

where <math>H_\text{T}</math> is the dose equivalent to an organ or tissue <math>\text{T}</math> and <math>w_\text{T}</math> is the tissue weighting factor. The SI unit of effective dose equivalent is joule per kilogramme (J kg<sup>-1</sup>), and its special name is sievert (Sv). A quantity introduced by ICRP in [[ICRP Publication 26|Publication 26]] (ICRP, 1977) and replaced by effective dose in [[ICRP Publication 60]] (ICRP, 1991).

''ICRP Glossary entry - May 2019''

'''Return to [[ICRP Glossary|Glossary]]'''

Committed effective dose

2026-09-10T00:33:09Z

Charlotte White:

The sum of the products of the sex-averaged committed organ- or tissue-equivalent doses, <math>H_\text{T}(τ)</math>, and the appropriate tissue weighting factors (<math>w_\text{T}</math>), where <math>τ</math> is the integration time in years following the intake. The commitment period <math>τ</math> is taken to be 50 years for adults, and to 70 years of age for children. (adapted from [[ICRP Publication 103]], 2007)

where <math>τ</math> is the integration time following the intake at time <math>t_0</math>. The quantity committed effective dose <math>E(τ)</math> is then given by:
<div style='text-align: center;'>
<math>
E(τ) = \displaystyle \sum_{\text{T}} w_\text{T}H_\text{T}(τ)
</math>
</div>

''ICRP Glossary entry - May 2019''

'''Return to [[ICRP Glossary|Glossary]]'''

Committed equivalent dose

2026-09-10T00:28:15Z

Charlotte White:

The time integral of the equivalent dose rate in a particular tissue or organ that will be received by an individual following intake of radioactive material into the body by a Reference Person, where <math>τ</math> is the integration time in years. ([[ICRP Publication 103]], 2007)

The committed equivalent dose (<math>H_\text{T}(τ)</math>) in a tissue or organ <math>\text{T}</math> is defined by:

<div style='text-align: center;'>
<math>
H_\text{T}(τ)= \int\limits_{t_0}^{t_0+τ} H_\text{T}(t)\text{d}t
</math>
</div>

''ICRP Glossary entry - May 2019''

'''Return to [[ICRP Glossary|Glossary]]'''

Committed equivalent dose

2026-09-10T00:26:20Z

Charlotte White:

The time integral of the equivalent dose rate in a particular tissue or organ that will be received by an individual following intake of radioactive material into the body by a Reference Person, where <math>τ</math> is the integration time in years. ([[ICRP Publication 103]], 2007)

The committed equivalent dose (<math>H_T(τ)</math>) in a tissue or organ <math>T</math> is defined by:

<div style='text-align: center;'>
<math>
H_\text{T}(τ)= \int\limits_{t_0}^{t_0+τ} H_\text{T}(t)\text{d}t
</math>
</div>

''ICRP Glossary entry - May 2019''

'''Return to [[ICRP Glossary|Glossary]]'''

Committed equivalent dose

2026-09-10T00:20:54Z

Charlotte White:

The time integral of the equivalent dose rate in a particular tissue or organ that will be received by an individual following intake of radioactive material into the body by a Reference Person, where <math>τ</math> is the integration time in years. ([[ICRP Publication 103]], 2007)

The committed equivalent dose (<math>H_T(τ)</math>) in a tissue or organ <math>T</math> is defined by:

<div style='text-align: center;'>
<math>
H_T(τ)= \int\limits_{t_0}^{t_0+τ} H_T(t)dt
</math>
</div>

''ICRP Glossary entry - May 2019''

'''Return to [[ICRP Glossary|Glossary]]'''

Committed equivalent dose

2026-09-02T15:45:10Z

Charlotte White:

The time integral of the equivalent dose rate in a particular tissue or organ that will be received by an individual following intake of radioactive material into the body by a Reference Person, where <math>τ</math> is the integration time in years. ([[ICRP Publication 103]], 2007)

The committed equivalent dose (<math>H_T(τ)</math>) in a tissue or organ <math>T</math> is defined by:

<div style='text-align: center;'>
<math>
H_t(τ)= \int\limits_{t_0}^{t_0+τ} H_t(t)dt
</math>
</div>

''ICRP Glossary entry - May 2019''

'''Return to [[ICRP Glossary|Glossary]]'''

Effective dose equivalent

2026-09-01T17:57:36Z

Charlotte White:

The tissue weighted sum of dose equivalent to an organ or tissue from all specified organs and tissues of the body, given by the expression

<div style='text-align: center;'>
<math>
H_E = \displaystyle \sum_{T} w_TH_T
</math>
</div>

where H<sub>T</sub> is the dose equivalent to an organ or tissue T and w<sub>T</sub> is the tissue weighting factor. The SI unit of effective dose equivalent is joule per kilogramme (J kg<sup>-1</sup>), and its special name is sievert (Sv). A quantity introduced by ICRP in [[ICRP Publication 26|Publication 26]] (ICRP, 1977) and replaced by effective dose in [[ICRP Publication 60]] (ICRP, 1991).

''ICRP Glossary entry - May 2019''

'''Return to [[ICRP Glossary|Glossary]]'''

Committed equivalent dose

2026-09-01T17:57:05Z

Charlotte White:

The time integral of the equivalent dose rate in a particular tissue or organ that will be received by an individual following intake of radioactive material into the body by a Reference Person, where s is the integration time in years. ([[ICRP Publication 103]], 2007)

The committed equivalent dose (<math>H_T(τ)</math>) in a tissue or organ <math>T</math> is defined by:

<div style='text-align: center;'>
<math>
H_T(τ)= \int\limits_{t_0}^{t_0+τ} H_T(t)dt
</math>
</div>

''ICRP Glossary entry - May 2019''

'''Return to [[ICRP Glossary|Glossary]]'''

Committed equivalent dose

2026-09-01T17:56:19Z

Charlotte White:

The time integral of the equivalent dose rate in a particular tissue or organ that will be received by an individual following intake of radioactive material into the body by a Reference Person, where s is the integration time in years. ([[ICRP Publication 103]], 2007)

The committed equivalent dose (<math>H_T(τ)</math>) in a tissue or organ <math>T</math> is defined by:

<div style='text-align: center;'>
<math>
H_T(τ)= \int\limits_{t_0}^{t_0+τ} H_T(T)dt
</math>
</div>

''ICRP Glossary entry - May 2019''

'''Return to [[ICRP Glossary|Glossary]]'''

Committed effective dose

2026-09-01T17:53:12Z

Charlotte White:

The sum of the products of the sex-averaged committed organ- or tissue-equivalent doses, <math>H_T(τ)</math>, and the appropriate tissue weighting factors (<math>w_T</math>), where <math>τ</math> is the integration time in years following the intake. The commitment period <math>τ</math> is taken to be 50 years for adults, and to 70 years of age for children. (adapted from [[ICRP Publication 103]], 2007)

where <math>τ</math> is the integration time following the intake at time <math>t_0</math>. The quantity committed effective dose <math>E(τ)</math> is then given by:
<div style='text-align: center;'>
<math>
E(τ) = \displaystyle \sum_{T} w_TH_T(τ)
</math>
</div>

''ICRP Glossary entry - May 2019''

'''Return to [[ICRP Glossary|Glossary]]'''

Derived consideration reference level

2024-07-15T16:01:11Z

Charlotte White:

[[File:Glossary Icon-2.png|100px|frameless|right|link=ICRP Glossary]]
A dose rate above which there is, for a given taxonomic class, a defined chance of deleterious effects of ionising radiation on individuals of a species that may lead to consequences at the population level.

(Adapted from [[ICRP Publication 136]], 2017)

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== Previous glossary entries ==

=== from [[ICRP Publication 136]], 2017 ===

A band of dose rate within which there is likely to be some chance of deleterious eﬀects of ionising radiation occurring to individuals of that type of Reference Animal or Plant (derived from a knowledge of deﬁned expected biological eﬀects for that type of organism) that when considered together with other relevant information can be used as a point of reference to optimise the level of eﬀort expended on environmental protection dependent upon the overall management objectives and the relevant exposure situation.

Derived consideration reference level

2024-07-15T16:00:30Z

Charlotte White: /* from ICRP Publication 136, 2017 */

[[File:Glossary Icon-2.png|100px|frameless|right|link=ICRP Glossary]]
A dose rate above which there is, for a given taxonomic class, a defined chance of deleterious effects of ionising radiation on individuals of a species that may lead to consequences at the population level.

(Adapted from [[ICRP Publication 137]], 2017)

'''Return to [[ICRP Glossary|Glossary]]'''

== Previous glossary entries ==

=== from [[ICRP Publication 136]], 2017 ===

A band of dose rate within which there is likely to be some chance of deleterious eﬀects of ionising radiation occurring to individuals of that type of Reference Animal or Plant (derived from a knowledge of deﬁned expected biological eﬀects for that type of organism) that when considered together with other relevant information can be used as a point of reference to optimise the level of eﬀort expended on environmental protection dependent upon the overall management objectives and the relevant exposure situation.

Utilitarian ethics

2021-09-07T14:57:02Z

Charlotte White:

An approach to ethics that judges the morality of an action based on the action’s impact on social welfare.

(Adapted from [[ICRP Publication 138]], 2018)

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Uptake

2021-09-07T14:56:46Z

Charlotte White:

[[File:Glossary Icon-2.png|100px|frameless|right|link=ICRP Glossary]]
Activity that enters blood from the respiratory or alimentary tract or through the skin.

See also [[Intake]].

(Adapted from [[ICRP Publication 130]], 2015)

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Upper reference levels

2021-09-07T14:56:27Z

Charlotte White:

[[File:Glossary Icon-2.png|100px|frameless|right|link=ICRP Glossary]]
Maximum values of exposure under which ICRP recommends national authorities to establish their own national reference levels.

(Adapted from [[ICRP Publication 115]], 2010)

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Unsealed source

2021-09-07T14:56:16Z

Charlotte White:

Radioactive material that is in a readily dispensable form i.e. neither permanently sealed in a capsule nor incorporated in a solid form.

(Adapted from [https://www.iaea.org/resources/safety-standards/safety-glossary IAEA Glossary], 2016)

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Unattached fraction

2021-09-07T14:55:55Z

Charlotte White:

[[File:Glossary Icon-2.png|100px|frameless|right|link=ICRP Glossary]]
The fraction of the [[potential alpha energy concentration]] of short-lived radon progeny that is not attached to the ambient aerosol.

(Adapted from [[ICRP Publication 115]], 2010)

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Voxel phantom

2021-09-07T14:34:37Z

Charlotte White:

[[File:Glossary Icon-2.png|100px|frameless|right|link=ICRP Glossary]]
Computational anthropomorphic phantom based on medical tomographic images where the anatomy is described by small three-dimensional volume elements (voxels) specifying the density and the atomic composition of the various organs and tissues of the human body.

See also [[reference phantom]].

(Adapted from [[ICRP Publication 103]], 2007)

'''Return to [[ICRP Glossary|Glossary]]'''

== Previous glossary entries ==

=== from [[ICRP Publication 116]], 2015 and [[ICRP Publication 123]], 2013 ===

Computational anthropomorphic phantom based on medical tomographic images in which the anatomy is described by small three-dimensional volume elements (voxels). Collections of these voxels are used to specify the organs and tissues of the human body.

=== from [[ICRP Publication 110]], 2008 ===

Computational anthropomorphic phantom based on medical tomographic images in which the anatomy is described by small three-dimensional volume elements (voxels) specifying the organ or tissue to which they belong.

Virtue ethics

2021-09-07T14:34:22Z

Charlotte White:

An approach to ethics that emphasizes the role of personal character and virtue in determination of morality.

(Adapted from [[ICRP Publication 138]], 2018)

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Valvular heart disease

2021-09-07T14:34:05Z

Charlotte White:

Heart disease due to one or more abnormal heart valves. Abnormally narrowed or leaky heart valves can interfere with the heart’s ability to push blood forward from chamber to chamber, and then out to the lungs, coronary arteries and aorta.

(Adapted from [[ICRP Publication 120]], 2012)

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Value judgement

2021-09-07T14:33:50Z

Charlotte White:

A subjective assessment based upon available knowledge and a particular set of values and priorities.

(Adapted from [[ICRP Publication 138]], 2018)

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Xerostomia

2021-09-07T14:33:27Z

Charlotte White:

Dryness of the mouth caused by malfunctioning salivary glands or composition of saliva. Xerostomia is also known to be caused by radiotherapy of the head and neck region.

(Adapted from [[ICRP Publication 118]], 2012)

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X ray

2021-09-07T14:33:05Z

Charlotte White:

Electromagnetic radiation emitted from outside the nucleus of an atom due to the energy loss of electrons.

'''Return to [[ICRP Glossary|Glossary]]'''

Growth hormone (somatotropin)

2021-09-07T14:32:15Z

Charlotte White:

A peptide hormone that stimulates growth, cell reproduction, and cell regeneration. Growth hormone is synthesized, stored and secreted by somatotropic cells within the anterior pituitary gland.

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Growth fraction

2021-09-07T14:31:44Z

Charlotte White:

Proportion of viable cells in active cell division.

(Adapted from [[ICRP Publication 118]], 2012)

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Growth factor

2021-09-07T14:31:31Z

Charlotte White:

[[File:Glossary Icon-2.png|100px|frameless|right|link=ICRP Glossary]]
An organic molecule that stimulates cell proliferation when it binds to its cellsurface receptor. Often synonymously termed ‘cytokine’.

(Adapted from [[ICRP Publication 131]], 2015)

'''Return to [[ICRP Glossary|Glossary]]'''

== Previous glossary entries ==

=== from [[ICRP Publication 118]], 2012 ===

A serum protein that stimulates cell division when it binds to its cell surface receptor.

=== from [[ICRP Publication 103]], 2007 ===

Molecules that act to control cell reproduction and proliferation/differentiation of a population of cells.

Granulocyte-macrophage colony-stimulating factor

2021-09-07T14:30:41Z

Charlotte White:

Cytokine that stimulates differentiation of progenitors into granulocytes, macrophages, and eosinophils.

(Adapted from [[ICRP Publication 118]], 2012)

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Granulocyte colony-stimulating factor

2021-09-07T14:30:24Z

Charlotte White:

Cytokine that stimulates differentiation of progenitor cells into granulocytes.

(Adapted from [[ICRP Publication 118]], 2012)

'''Return to [[ICRP Glossary|Glossary]]'''

Graft vs host disease

2021-09-07T14:29:37Z

Charlotte White:

[[File:Glossary Icon-2.png|100px|frameless|right|link=ICRP Glossary]]
In transplants, reaction by immunologically competent cells of the donor against the antigens present on the cells of the host. Often a fatal condition in human bone marrow transplants.

(Adapted from [[ICRP Publication 118]], 2012)

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Graded approach

2021-09-07T14:29:20Z

Charlotte White:

The scheme recommended for implementing the system of protection in a way that is proportionate to the magnitude and likelihood of the risk, the complexity of the exposure situation and the prevailing circumstances.

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Rigidity threshold

2021-09-07T14:29:02Z

Charlotte White:

For each point inside the Earth´s magnetosphere and each direction from that point, there exists a rigidity threshold below which the cosmic particles are not able to reach this point. This rigidity is called the ‘geomagnetic cut-off rigidity’.

(Adapted from [[ICRP Publication 123]], 2013)

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Genomic integrity

2021-09-07T14:28:47Z

Charlotte White:

GATA binding protein 2

2021-09-07T14:28:24Z

Charlotte White:

[[File:Glossary Icon-2.png|100px|frameless|right|link=ICRP Glossary]]
Master regulatory gene encoding for zinc finger DNA binding domain transcription factors/regulatory gene/gene product for early haematopoietic progenitor cells.

(Adapted from [[ICRP Publication 131]], 2015)

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Gastroschisis

2021-09-07T14:28:10Z

Charlotte White:

[[File:Glossary Icon-2.png|100px|frameless|right|link=ICRP Glossary]]
A congenital defect characterised by a defect in the anterior abdominal wall through which the abdominal contents protrude freely.

(Adapted from [[ICRP Publication 131]], 2015)

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Gastrulation

2021-09-07T14:27:59Z

Charlotte White:

[[File:Glossary Icon-2.png|100px|frameless|right|link=ICRP Glossary]]
Early phase in the embryonic development of most animals, during which the single-layered blastula is re-organised into a three-layered gastrula comprising the ectoderm, mesoderm, and endoderm.

(Adapted from [[ICRP Publication 131]], 2015)

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Gastrointestinal syndrome

2021-09-07T14:27:39Z

Charlotte White:

The signs and symptoms of intestinal failure; e.g. intestinal damage related to an acute exposure to ionising radiation with a threshold of about 10 Gy. Acute radiation syndrome (ARS) is a collection of such health effects that are present within 24 hours of exposure.

'''Return to [[ICRP Glossary|Glossary]]'''

Gamma ray

2021-09-07T14:27:21Z

Charlotte White:

Gamma-rays are electromagnetic radiations (photons) emitted by the nucleus in transition from a high energy state to a lower energy state.

(Adapted from [[ICRP Publication 107]], 2007)

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Galactic cosmic radiation

2021-09-07T14:27:06Z

Charlotte White:

Charged particle radiation that enters the heliosphere continuously from outer space from all directions. The radiation contains electrons (approximately 2%) and a broad range of charged particles from protons up to high Z particles with energies up to several hundreds of GeV and even higher. The fluence rate of GCR in the heliosphere is inversely correlated with the solar activity. It is caused by the solar magnetic field, which is coupled to the solar wind.

(Adapted from [[ICRP Publication 123]], 2013)

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Fractionation sensitivity

2021-09-07T14:26:17Z

Charlotte White:

The dependence of the iso-effective radiation dose on the dose per fraction. Usually quantified by the [[α/β ratio]] – a high fractionation sensitivity is characterised by a low [[α/β ratio]].

(Adapted from [[ICRP Publication 118]], 2012)

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Fractionation and dose delivery patterns

2021-09-07T14:26:00Z

Charlotte White:

[[File:Glossary Icon-2.png|100px|frameless|right|link=ICRP Glossary]]
The dose per fraction of radiation is the total dose divided into a particular number of fractions. A very large number of extremely small dose fractions becomes equivalent to low-dose-rate exposure. Very low dose rates protracted over long durations are called ‘chronic exposures’.

(Adapted from [[ICRP Publication 131]], 2015)

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Fractionation

2021-09-07T14:25:45Z

Charlotte White:

The dose in radiotherapy based on the total dose divided into a particular number of (usually) daily or shorter treatments.

(Adapted from [[ICRP Publication 118]], 2012)

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Fractional absorption in the gastrointestinal tract

2021-09-07T14:25:30Z

Charlotte White:

[[File:Glossary Icon-2.png|100px|frameless|right|link=ICRP Glossary]]
The fraction of an element directly absorbed from the alimentary tract into blood, referred to as the gut transfer factor, and designated as f<sub>1</sub> in the [[ICRP Publication 30]] gastrointestinal tract model and f<sub>A</sub> in the revised [[ICRP Publication 100]] [[Human Alimentary Tract Model]].

(Adapted from [[ICRP Publication 130]], 2015)

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== Previous glossary entries ==

=== from [[ICRP Publication 119]], 2012 ===

The f<sub>1</sub> value is the fraction of an ingested element absorbed directly into body fluids.

Forbiddenness

2021-09-07T14:25:21Z

Charlotte White:

Beta transitions are classified as allowed transition or forbidden transition based on the spin and parity of the nuclear states involved in the transition. Forbiddenness indicates how ‘fast’ the transition occurs.

(Adapted from [[ICRP Publication 107]], 2007)

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Fluoroscopically or computed tomography guided interventions

2021-09-07T14:24:55Z

Charlotte White:

[[File:Glossary Icon-2.png|100px|frameless|right|link=ICRP Glossary]]
Procedures comprising image guided therapeutic or diagnostic interventions by percutaneous or other access usually performed under local anaesthesia and/or sedation with ﬂuoroscopy or computed tomography (CT). Three-dimensional (cone beam CT) imaging using ﬂuoroscopic equipment is also used in some interventional procedures.

(Adapted from [[ICRP Publication 139]], 2018)

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== Previous glossary entries ==

=== from [[ICRP Publication 139]], 2018 ===

Procedures comprising guided therapeutic and diagnostic interventions by percutaneous or other access usually performed under local anaesthesia and/or sedation with ﬂuoroscopic or computed tomography (CT) imaging used to localise the lesion/treatment site monitor the procedure and control and document the therapy (ICRP 2000b). Three-dimensional (cone beam CT) imaging using ﬂuoroscopic equipment is also used in some interventional procedures.

Fluence

2021-09-07T14:24:42Z

Charlotte White:

[[File:Glossary Icon-2.png|100px|frameless|right|link=ICRP Glossary]]
The quotient of <math>dN</math> by <math>da</math>, where <math>dN</math> is the number of particles incident on a sphere of cross-sectional area <math>da</math>, thus:

<math>\Phi = \frac{dN}{da}</math>

The unit of fluence is <sup>m-2</sup>.

(Adapted from [[ICRP Publication 116]], 2010)

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== Previous glossary entries ==

=== from [[ICRP Publication 103]], 2007; [[ICRP Publication 110]], 2008; [[ICRP Publication 119]], 2012 ===

The quotient of <math>dN</math> by <math>da</math>, where <math>dN</math> is the number of particles incident on a small sphere of cross-sectional area <math>da</math>, thus:

<math>\Phi = \frac{dN}{da}</math>

Fluoroscopically guided interventions

2021-09-07T14:24:28Z

Charlotte White:

Minimal invasive procedures comprising fluoroscopic guided therapeutic and diagnostic interventions, by percutaneous, endoscopic or other access, usually performed under local anaesthesia and/or sedation; e.g. in radiology, cardiology, gastroenterology or urology.

(Adapted from [[ICRP Publication 120]], 2012)

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Flexible tissues

2021-09-07T14:24:02Z

Charlotte White:

In flexible (Type F) tissues all cells are assumed to have the potential for proliferation and are also engaged in tissue-specific functions. The pronounced dose-latency relationship results from the dose-dependent loss of proliferating functional cells through their mitotic death, together with the feedback-mediated stimulation of compensatory proliferation, leading to an even enhanced cell loss by doomed divisions.

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Field-size effect (Volume effect)

2021-09-07T14:23:51Z

Charlotte White:

The dependence of normal tissue damage on the size of the irradiated area (particularly in skin); in modern literature, typically referred to as the ‘volume effect’. Larger field sizes lead to more scattered radiation, which increases the dose in a specified volume.

(Adapted from [[ICRP Publication 118]], 2012)

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Fairness

2021-09-07T14:23:38Z

Charlotte White:

The quality of treating people equitably or in a way that is right or reasonable.

(Adapted from [[ICRP Publication 138]], 2018)

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Kp index

2021-09-07T14:22:53Z

Charlotte White:

Index quantifying disturbances in the horizontal component of the Earth's magnetic field with a number in the range 0–9, with 1 being calm and ≥5 indicating a geomagnetic storm. The K index is derived from the maximum fluctuations of horizontal components observed on a magnetometer during a 3-h interval. The official planetary Kp index is derived by calculating a weighted average of K indices from a network of geomagnetic observatories.

(Adapted from [[ICRP Publication 132]], 2013)

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