Effects of Exposure
For the purposes of radiological protection, harmful effects of radiation exposure are grouped into two categories:
| Deterministic Effects
Effects, such as skin burns, that only appear at relatively high doses.
| Stochastic Effects
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.
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 dose of 100 mGy (above the 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.
|Stochastic effects include cancer and heritable effects.
There is reliable scientific evidence that 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.
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.
Quotes from ICRP Publications
|Types of effects: Publication 103 paragraph 55
Publication 103 paragraph 58
Publication 118 paragraph 10
|Publication 103 paragraph 62
The 'LNT' model: Publication 103 paragraphs 65 and 66
Genetic effects: Publication 103 paragraph 74