For many years after Hiroshima and Nagasaki much of the research on the effects of ionising radiations was naturally concentrated on the results of sudden whole-body exposure. But in a world that was likely to rely more and more on atomic power, the ultimate effects of low doses, slowly absorbed, clearly needed fuller comprehension. Three new reports from the United States National Academy of Sciences reflect the increasing research effort directed towards these chronic effects that are so hard to investigate.

The study of the association of radiation with leukaemia has been more exact than other inquiries because a fatal condition lends itself to mortality comparisons: the subtle and indefinite changes of premature ageing, another possible effect of radiation, are far harder to assess, particularly since physiological senescence is itself ill-understood. The epidemiological investigations - vast animal experiments and prospective inquiries on people whose occupation involves exposure to low doses - are complementary methods which may eventually show whether average life expectancy is reduced: but so many variables are involved that the answer may be a very long time coming; and the application of animal data to man is full of uncertainty. A prospective inquiry benefits from the fact that most of the nuclear agencies and X-ray departments in the United States and Great Britain keep careful medical and radiation exposure records of their employees. The larger the sample the better, and if it were possible to adopt common methods of measurement and recording throughout the world, much valuable information might be obtained. Differences which might be hidden when manifold recording methods allow only indirect comparisons might be revealed under standard conditions and suggest important new ideas. There seems to be a case for an international meeting of radiation-medicine and epidemiological experts to consider how to exploit such an opportunity. The best treatment of the acute radiation syndrome is in most particulars generally agreed upon: the one controversial point is the value of bone-marrow therapy. If the normal immunological response has been almost completely suppressed by radiation, it may be possible, by marrow transfusion, to tide a patient over temporary failure of the haemopoietic system. On the other hand, there is a risk of a foreign tissue reaction, which could prove fatal to anyone seriously ill. If the dose of radiation is known to be so high that the patient faces almost certain death, it is justifiable to grasp at any straw; and some experts advise that this should be the indication for giving bone-marrow therapy. As far as present knowledge goes this advice is wise; but it is to be hoped that experimental work will soon permit more room for clinical manoeuvre.

(from The Lancet, 10th June, 1961)