SOME EFFECTS ON LYMPHOID CELLS OF 



OCCUPATIONAL AND ACCIDENTAL EXPOSURE 



TO IONIZING RADIATIONS 



D. O. Shiels 

 Melbourne 



INTRODUCTION 



According to numerous authorities the earHest sign of the effects of ionizing 

 radiation on the blood is a reduction in white cell count or in the lymphocyte 

 count. The object of this paper is to show that certain other changes are 

 more sensitive and consistent indications than either of these, of the effects 

 of minor degrees of ionizing radiation. 



Evidence has previously been adduced^' ^' ^' ^ that when comparison 

 was made between a group of persons occupationally exposed to ionizing 

 radiations and a group of persons not so exposed, there were in the former 

 group the following changes from the normal: an increase in the ratio of 

 large lymphocytes plus monocytes to small lymphocytes; an increase in the 

 ratio of large lymphocytes to small lymphocytes; a decrease in the percentage 

 of lymphocytes which show granules in the cytoplasm, and an increase in the 

 percentage of the monocytes which were of a particular type, and certain 

 indices derived from these. Evidence was also produced- that the tests for 

 these factors are more sensitive and consistent than aie the usual blood 

 counts, in indicating effects of ionizing radiation. 



Any criticism to the effect that the deviations from the normal blood picture 

 were due to factors other than radiation, such as overwork, fatigue, bad 

 ventilation, sub-clinical infection, worry, etc., never had much weight since 

 the controls were also subject to similar influences. Comment has been made 

 by Russ^ in reference to the ratios that other factors not yet recognized 

 might be at work, such as apprehension over dangers or reaction to a new 

 environment. Such factors could not apply in the case of persons exposed 

 to ionizing radiation of which they had no knowledge. Such were the circum- 

 stances in the accidental exposures dealt with in this paper. Neither the 

 adults nor the children had any apprehension of danger, nor were they 

 aware of being exposed to any new environment. 



It is reasonably certain, therefore that the effects on the blood which were 

 found in these accidental exposure cases were due to ionizing radiation 

 even though the exposures in most of the cases were not great. A short 

 description of the occurrences is given below. 



accidental exposures 



The Caesium Incident 



A man aged al:)out 28 years (Mr. X) carried about at work for a week, in 



the front thigh pocket of his overalls, a capsule containing 2 • 5 curies of 



4 37 



