INTRODUCTION 235 



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Figure 9-1. Abnormal Bone Growths in the Hand — Similar to those Suffered 

 by the Early Radiologists. (Courtesy of A. F. Crook, Ottawa General Hospital.) 



Recognition of these effects led to controls which by this time have com- 

 pletely removed, in medical use, the gross dangers described above, although 

 there are still subtle possibilities, as we shall see, which may yet require that 

 even further restrictions be instituted. Some dangers are not so subtle: this 

 is the era of the megaton bomb. 



Nonmedical applications of ionizing radiation are increasing rapidly, and 

 render it important that safety measures and medical checks be more and 

 more indicative of absorbed dose. For instance, the development of atomic 

 power stations, irradiation-sterilization of food (potatoes, for example, to 

 keep them from sprouting during long shipment) and of surgical and medi- 

 cal supplies, the production of new chemical polymers by irradiation, the 

 detection of faults and flaws in metal castings and welds by X-ray fluoros- 

 copy: all involve skilled and unskilled human labor. Furthermore, the in- 

 creasing radioactivity "background" of the environment — even to the in- 

 creasing tritium (two neutrons + one proton; a beta-emitter) content of our 

 water supplies (blood is about 90 per cent water!) — makes it obvious, al- 

 though perhaps distasteful, that man is being more and more heavily ir- 

 radiated every day (Figure 9-2). Therefore the effects, especially the subtle 

 ones, which may show up only after a few generations, must be understood 



