Ionizing radiation and cancer

From quantitative point of view ionizing radiation is not a major cause of cancer. It has been assessed that it is responsible for only 1-2% of all cancer and even in a heavily exposed population as the A-bomb survivors it has increased the cancer mortality only by a few per cent. It is, however, often a discrepency between 'risk assessment' and 'risk perception' when it concerns cancer risks and this discrepency is especially large for ionizing radiation. Many persons in Sweden are worried about the carcinogenic risk of the Chernobyl outfall. The collective effective dose equivalent of this outfall in Sweden during the first 50 years has been estimated to 5000-10000Sv, which with a risk coeffcient of 2x10-2Sv-1 corresponds to 100-200 hypothetical cancer deaths. This should be compared to the about 1 million 'normal' cancer deaths which can be expected during a 50 year period, i.e. the out-fall may hypothetically increase the cancer mortality by 0.01-0.02%