Effects of Exposure - Revision history

Chris Clement at 17:22, 7 June 2019

2019-06-07T17:22:06Z

Chris Clement: Undo revision 1339 by Clement (talk)

2019-06-07T17:21:17Z

Undo revision 1339 by Clement (talk)

Chris Clement: Reverted edits by Clement (talk) to last revision by Admin

2019-06-07T17:20:33Z

Reverted edits by Clement (talk) to last revision by Admin

Chris Clement at 17:19, 7 June 2019

2019-06-07T17:19:58Z

Chris Clement: /* Quotes from ICRP Publications */

2019-03-08T21:09:14Z

‎Quotes from ICRP Publications

Chris Clement at 21:07, 8 March 2019

2019-03-08T21:07:25Z

Admin: 1 revision imported

2019-03-05T17:23:56Z

1 revision imported

icrpaedia>Clement at 14:07, 31 January 2018

2018-01-31T14:07:51Z

New page

__NOTOC__
<span style= "font-size:110%;"> '''For the purposes of radiological protection, harmful effects of radiation exposure are grouped into two categories:''' </span>

{|width= 95%
| <span style="color:#4682B4; font-size:115%"> '''Deterministic Effects''' </span>

Effects, such as skin burns, that only appear at relatively high doses.
| <span style="color:#4682B4; font-size:115%"> '''Stochastic Effects''' </span>

Effects, such as cancer, that are assumed to pose some risk even at low doses.
|}

==<span class="mw-collapsible-headline">Details</span>==

<div id="collapse-pre-one" class="mw-collapsible mw-collapsed">
<div class="mw-collapsible-toggle">
<div class="mw-collapsible-toggle-row">
<div class="mw-collapsible-toggle"><span style="color:#ffffff;">[see more/less]</span></div>
</div>
</div>
<br />
<div class="mw-collapsible-content">

{|width= 95%
|style="width: 45%; vertical-align:top;" | Deterministic effects are also referred to as ''harmful tissue reactions''.

They include, for example, skin burns and damage to the lens of the eye.

These effects do not appear below a dose threshold. Above this threshold, the higher the dose the more severe the effect.

No deterministic effects would be expected below an [[Absorbed, Equivalent, and Effective Dose | absorbed dose]] of 100 mGy (above the [[Sources of Radiation Exposure | natural background exposure]]), and thresholds for most effects are much higher. Because of this, deterministic effects are rare, although they can occur as a result of sophisticated medical procedures, or accidents.

In extremely rare cases, such as in severe accidents, very high doses received in a very short time can lead to acute radiation syndrome and even death.
|style="width: 4%;" |
|style="width: 45%; vertical-align:top;" | Stochastic effects include cancer and heritable effects.

There is reliable scientific evidence that [[Absorbed, Equivalent, and Effective Dose | doses]] above 100 mSv can increase the risk of cancer. Below this dose the evidence is less clear, but for purposes of radiological protection it is assumed that even small doses might result in small increased risk.

An extra [[Absorbed, Equivalent, and Effective Dose | effective dose]] of 200 mSv (above the [[ Sources of Radiation Exposure | natural background exposure]]) increases the risk of fatal cancer from the typical worldwide average of about 25% to about 26%.

Although heritable (genetic) effects have been seen in animals, none have ever been seen in humans. Even so, for protection purposes, a small risk of heritable effects is assumed.
|}
</div>
----
{| width= 98%
|style="width: 14%;" | <center> [[Image: unscear_logo.gif |100px|link=]] </center>
| style="width: 70%;" | <center> The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) is the leading international body on radiation levels and effects. [https://mediawiki.org Visit the UNSCEAR website] or read the [https://mediawiki.org UNEP report on "Radiation Effects and Sources"] based on UNSCEAR work to learn more. </center>
| style="width: 14%;" | <center>[[Image: unep.jpeg |90px|link=]] </center>
|}
----

==<span class="mw-collapsible-headline">Quotes from ICRP Publications</span>==

<div id="collapse03" class="mw-collapsible mw-collapsed">
<div class="mw-collapsible-toggle">
<div class="mw-collapsible-toggle-row">
<div class="mw-collapsible-toggle"><span style="color:#ffffff;">[see more/less]</span></div>
</div>
</div>
<br />

<div class="mw-collapsible-content">

{|width= 100%
|style="width: 45%; vertical-align:top;" | '''Types of effects: ''Publication 103'' paragraph 55'''

<blockquote>Most adverse health effects of radiation exposure may be grouped in two general categories:
*deterministic effects (harmful tissue reactions) due in large part to the killing/ malfunction of cells following high doses; and
*stochastic effects, i.e., cancer and heritable effects involving either cancer development in exposed individuals owing to mutation of somatic cells or heritable disease in their offspring owing to mutation of reproductive (germ) cells.</blockquote>

'''''Publication 103'' paragraph 58'''

<blockquote>The induction of tissue reactions is generally characterised by a threshold dose. The reason for the presence of this threshold dose is that radiation damage (serious malfunction or death) of a critical population of cells in a given tissue needs to be sustained before injury is expressed in a clinically relevant form. Above the threshold dose the severity of the injury, including impairment of the capacity for tissue recovery, increases with dose.
</blockquote>

'''''Publication 118'' paragraph 10'''

<blockquote> The manifestations of tissue injury vary from one tissue to another depending on cellular composition, proliferation rate, and mechanisms of response to radiation, which may be highly tissue specific. Examples ... include cataracts of the lens of the eye, non-malignant damage to the skin, cell depletion in the bone marrow causing haematological deficiencies, and gonadal cell damage leading to impairment of fertility. Tissue reactions, especially late reactions, also depend on damage to blood vessels or elements of the extracellular matrix, which are common to most organs of the body. </blockquote>

|style="width: 45%; " | '''''Publication 103'' paragraph 62'''

<blockquote> In the case of cancer, epidemiological and experimental studies provide evidence of radiation risk albeit with uncertainties at doses about 100 mSv or less. In the case of heritable diseases, even though there is no direct evidence of radiation risks to humans, experimental observations argue convincingly that such risks for future generations should be included in the system of protection. </blockquote>

'''The 'LNT' model: ''Publication 103'' paragraphs 65 and 66'''

<blockquote>... the practical system of radiological protection ... will continue to be based upon the assumption that at doses below about 100 mSv a given increment in dose will produce a directly proportionate increment in the probability of incurring cancer or heritable effects attributable to radiation. This dose-response model is generally known as ‘linear-non-threshold’ or LNT. ... the adoption of the LNT model ... provides a prudent basis for the practical purposes of radiological protection, i.e., the management of risks from low-dose radiation exposure.

... whilst the LNT model remains a scientifically plausible element in its practical system of radiological protection, biological/epidemiological information that would unambiguously verify the hypothesis that underpins the model is unlikely to be forthcoming ... Because of this uncertainty on health effects at low doses, ... it is not appropriate, for the purposes of public health planning, to calculate the hypothetical number of cases of cancer or heritable disease that might be associated with very small radiation doses received by large numbers of people over very long periods of time ... </blockquote>

'''Genetic effects: ''Publication 103'' paragraph 74'''

<blockquote> There continues to be no direct evidence that exposure of parents to radiation leads to excess heritable disease in offspring. However, ... there is compelling evidence that radiation causes heritable effects in experimental animals. Therefore, the Commission prudently continues to include the risk of heritable effects in its system of radiological protection. </blockquote>
|}
</div>

@@ Line 22: / Line 22: @@
 '''Effects, such as cancer, that are assumed to pose some risk even at low doses.'''
-Stochastic effects include cancer and heritable effects.
+Stochastic effects include ''cancer and heritable effects''.
 There is reliable scientific evidence that [[Absorbed, Equivalent, and Effective Dose | doses]] above 100 mSv can increase the risk of cancer. Below this dose the evidence is less clear, but for purposes of radiological protection it is assumed that even small doses might result in small increased risk.

@@ Line 75: / Line 75: @@
 </blockquote>
-'''''ICRP Publication 118'' paragraph 10'''
+'''''[[ICRP Publication 118]]'' paragraph 10'''
 <blockquote> The manifestations of tissue injury vary from one tissue to another depending on cellular composition, proliferation rate, and mechanisms of response to radiation, which may be highly tissue specific. Examples ... include cataracts of the lens of the eye, non-malignant damage to the skin, cell depletion in the bone marrow causing haematological deficiencies, and gonadal cell damage leading to impairment of fertility. Tissue reactions, especially late reactions, also depend on damage to blood vessels or elements of the extracellular matrix, which are common to most organs of the body. </blockquote>

@@ Line 6: / Line 6: @@
 | <span style="color:#4682B4; font-size:115%"> '''Deterministic Effects''' </span>
-Effects, such as skin burns, that only appear at relatively high doses.
+'''Effects, such as skin burns, that only appear at relatively high doses.'''
-Effects, such as cancer, that are assumed to pose some risk even at low doses.
+Deterministic effects are also referred to as ''harmful tissue reactions''.
 They include, for example, skin burns and damage to the lens of the eye.
@@ Line 33: / Line 17: @@
 In extremely rare cases, such as in severe accidents, very high doses received in a very short time can lead to acute radiation syndrome and even death.
-|style="width: 4%;" |
-|style="width: 45%; vertical-align:top;" | Stochastic effects include cancer and heritable effects.
+| <span style="color:#4682B4; font-size:115%"> '''Stochastic Effects''' </span>
 There is reliable scientific evidence that [[Absorbed, Equivalent, and Effective Dose | doses]] above 100 mSv can increase the risk of cancer. Below this dose the evidence is less clear, but for purposes of radiological protection it is assumed that even small doses might result in small increased risk.
@@ Line 42: / Line 30: @@
 Although heritable (genetic) effects have been seen in animals, none have ever been seen in humans. Even so, for protection purposes, a small risk of heritable effects is assumed.
 |}
 ==<span class="mw-collapsible-headline">Quotes from ICRP Publications</span>==
@@ Line 64: / Line 44: @@
 {|width= 100%
-|style="width: 45%; vertical-align:top;" | '''Types of effects: ''Publication 103'' paragraph 55'''
+|style="width: 45%; vertical-align:top;" | '''Types of effects: ''[[ICRP Publication 103]]'' paragraph 55'''
 <blockquote>Most adverse health effects of radiation exposure may be grouped in two general categories:
@@ Line 70: / Line 50: @@
 *stochastic effects, i.e., cancer and heritable effects involving either cancer development in exposed individuals owing to mutation of somatic cells or heritable disease in their offspring owing to mutation of reproductive (germ) cells.</blockquote>
-'''''Publication 103'' paragraph 58'''
+'''''[[ICRP Publication 103]]'' paragraph 58'''
 <blockquote>The induction of tissue reactions is generally characterised by a threshold dose. The reason for the presence of this threshold dose is that radiation damage (serious malfunction or death) of a critical population of cells in a given tissue needs to be sustained before injury is expressed in a clinically relevant form. Above the threshold dose the severity of the injury, including impairment of the capacity for tissue recovery, increases with dose.
 </blockquote>
-'''''Publication 118'' paragraph 10'''
+'''''[[ICRP Publication 118]]'' paragraph 10'''
 <blockquote> The manifestations of tissue injury vary from one tissue to another depending on cellular composition, proliferation rate, and mechanisms of response to radiation, which may be highly tissue specific. Examples ... include cataracts of the lens of the eye, non-malignant damage to the skin, cell depletion in the bone marrow causing haematological deficiencies, and gonadal cell damage leading to impairment of fertility. Tissue reactions, especially late reactions, also depend on damage to blood vessels or elements of the extracellular matrix, which are common to most organs of the body. </blockquote>
-|style="width: 45%; " | '''''Publication 103'' paragraph 62'''
+|style="width: 45%; " | '''''[[ICRP Publication 103]]'' paragraph 62'''
 <blockquote> In the case of cancer, epidemiological and experimental studies provide evidence of radiation risk albeit with uncertainties at doses about 100 mSv or less. In the case of heritable diseases, even though there is no direct evidence of radiation risks to humans, experimental observations argue convincingly that such risks for future generations should be included in the system of protection. </blockquote>
-'''The 'LNT' model: ''Publication 103'' paragraphs 65 and 66'''
+'''The 'LNT' model: ''[[ICRP Publication 103]]'' paragraphs 65 and 66'''
 <blockquote>... the practical system of radiological protection ... will continue to be based upon the assumption that at doses below about 100 mSv a given increment in dose will produce a directly proportionate increment in the probability of incurring cancer or heritable effects attributable to radiation. This dose-response model is generally known as ‘linear-non-threshold’ or LNT. ... the adoption of the LNT model ... provides a prudent basis for the practical purposes of radiological protection, i.e., the management of risks from low-dose radiation exposure.
@@ Line 89: / Line 69: @@
 ... whilst the LNT model remains a scientifically plausible element in its practical system of radiological protection, biological/epidemiological information that would unambiguously verify the hypothesis that underpins the model is unlikely to be forthcoming ... Because of this uncertainty on health effects at low doses, ... it is not appropriate, for the purposes of public health planning, to calculate the hypothetical number of cases of cancer or heritable disease that might be associated with very small radiation doses received by large numbers of people over very long periods of time ... </blockquote>
-'''Genetic effects: ''Publication 103'' paragraph 74'''
+'''Genetic effects: ''[[ICRP Publication 103]]'' paragraph 74'''
 <blockquote> There continues to be no direct evidence that exposure of parents to radiation leads to excess heritable disease in offspring. However, ... there is compelling evidence that radiation causes heritable effects in experimental animals. Therefore, the Commission prudently continues to include the risk of heritable effects in its system of radiological protection. </blockquote>
 |}
 </div>

← Older revision	Revision as of 17:23, 5 March 2019
(No difference)