Doses and Biological Effects

From data given above a whole body effective dose of 1mSv gives rise to a probability of 40 in a million (4 x 10-5) of developing a fatal cancer.  This risk estimate can be compared to the risks of death associated with other occupations, and with the probability of dying from other causes:

Table: Average annual risk of death in the UK

SOURCE	RISK OF DEATH (PER YEAR)
Natural causes, 40 years old	1 in 700
Modern Life (Unavoidable):
Accidents on the road	1 in 10,000
Accidents in the home	1 in 25,000
Nuclear Discharges (max.)	1 in 70,000
Occupational Hazards*:
Sea Fishing Industry	1 in 500
Clothing and Footwear	1 in 300,000
Radiation Worker (Medical - 0.1mSv))	1 in 250,000
Accidents at work (all workers)	1 in 50,000
Medical Investigations:
Chest X-Ray (ave. 0.05mSv)	1 in 500,000
Barium Enema (ave. 7.7mSv)	1 in 3,250
Bone Scan (ave. 4mSv)	1 in 6,250
Voluntary Acts:
Smoking 20 cigarettes per day	1 in 100
Rock climbing for 5 hours	1 in 5,000
Canoeing for 10 hours	1 in 10,000
TOTAL (ALL CAUSES)	1 in 80

* - Source for Occupational Hazards - HSE 1982.

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It should be noted:

• the average annual risk of death from 0.1mSv is much less than that from all accidents at work averaged together.
• the probability of developing a fatal cancer from 0.1mSv per year is only approximately 1/10th the risk of dying from an accident in the home.

Other risks that may be quoted, in terms of "one in a million" include:

• smoking 1 cigarette (in a lifetime)
• travelling 50 miles by car
• travelling 250 miles by air
• rock climbing for 1.5 minutes
• canoeing for 6 minutes
• being aged 60 for 20 minutes
• being aged 30 for 9 hours

 

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Conversely a positron may be created when the nucleus has too many protons to be stable and it is the changing of a proton into a neutron with the subsequent release of a positron particle that accounts for the genesis positrons.

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