LEUKAEMIA INDUCED BY RADIATION 



J. F. LOUTIT 



Medical Research Council Radiobiological Research Unit, 

 Atomic Energy Research Establishment, Harwell, England 



During the last generation the incidence of leukaemia in the populations 

 of Western Europe and the United States of America has been increasing at 

 a steady rate to more than double its former value. There are many who 

 will incriminate radiation as the cause of this. 



Certainly there has been a very steady and great increase in the use of 

 X-rays for medical purposes. However, it is not the increased number of 

 X-ray pictures taken which is important, but the average dose to the popu- 

 lation due to the fact. Undoubtedly, over the same period of time there 

 have been considerable technological improvements and the dose delivered 

 to the patient during each exposure must undoubtedly have lessened with 

 time. Only in the last few years have estimates been made for the average 

 population dose. In 1956 the Medical Research Council in its report: 

 The Hazards to Man of Nuclear and Allied Radiations, gave their appreci- 

 ation of the average dose to the gonads. This was relevant to the under- 

 standing of the genetic hazards of radiation, but when we consider leukaemia 

 it is the dose to the haemopoietic tissues in which we are interested. In 

 Table 1 1 of Appendix C of the more recent report of the United Nations 

 Scientific Committee on the Effects of Atomic Radiation an estimate has 

 been made of the annual mean dose to the marrow from diagnostic X-ray 

 exposure. In Australia, Martin^ had estimated this dose to be about 

 100 mREM. The figure given by the United Nations Scientific Committee 

 was rather lower than that of Martin, but certainly of the same order. 

 However, as we have fewer data on which to calculate restrospectively 

 doses of a generation ago, we cannot yet compare the present state of affairs 

 with the past. 



Furthermore, we must always remember that it is not only radiological 

 practice which has changed during the last generation. The statistical 

 data are sufficiently good only for those countries with a high degree of 

 civilization and the conditions of life there have altered markedly during 

 this generation. We must remember that changes in the smoking habits of 

 the population and the change from coal to oil as a source of fuel have been 

 incriminated, rightly or wrongly, for the coincident rise in cancer of the 

 lung. In medical circles one must not forget that in this period we have 

 seen the rise of the sulphonamides, the anti-histamines, the antibiotics and 

 a host of other widely used chemical therapeutic agents. Today life in 

 general is just different from thirty years ago. 



However, let us return to radiation. There is now abundant evidence that 



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