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Risk factor

Risk factor is a quantitative measure of radiation hazards. It is an essential factor which should be considered in assessing the deleterious effects of radiation and setting up dose limits. The table on the right shows the probability of getting fatal diseases due to exposure to radiation.

This risk factor table roughly shows the relationship between radiation doses and its effects on human body. It should be note that experimental data for dose-effect relationship are still scanty, especially for low doses and low dose rates. The risk factors are deduced from a single exposure of more than 1 Gy and are subject to certain uncertainties. The figures are therefore neither precise nor final. They should be used carefully mindful of their limitations.






Tissue or organ

Probability of fatal cancer
(10-4 Sv-1)

Bladder 30
Bone marrow 50
Bone surface 5
Breast 20
Colon 85
Liver 15
Lung 85
Oesophagus 30
Ovary 10
Skin 2
Stomach 110
Thyroid 8
remainder1 50
Total 500
1 remainder: adrenals, brain, upper large intestine, small intestine, kidney, muscle, pancreas, spleen, thymus and uterus

The probability of getting fatal cancer due to exposure to radiation

(Source : 1990 Recommendations of the International Commission on Radiological Protection (ICRP Publication No. 60))

The above information is provided by RHU of DH
Department of Health

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Last revision date: <19 Dec 2012>