CHAPTER 9 



Biological Effects of 

 Ionizing Radiations 



The damage to living tissues caused by ionizing radiations was not al- 

 ways as well recognized as it is today, and many of the early investigators 

 suffered painfully as a result. On a memorial unveiled in Hamburg, 

 Germany, in 1936, in honor of the first 1 10 investigators and physicians 

 who died directly as a result of X-irradiatwn, following W. K. Roentgen 's 

 discovery in 7895, we read the dedication : 



"To the Roentgenologists and Radiologists of all Nations who have 

 given their lives in the struggle against the diseases of mankind. " 



INTRODUCTION 



This chapter could have been the longest in the book. Indeed, it could 

 have been expanded to be the whole book, for such is the importance of bio- 

 logical effects of ionizing radiations, both for diagnosis and for therapy. 

 However, we restrict ourselves here to the principles which are necessary to 

 an understanding of the effects. Although some examples are given to illustrate 

 the effects on humans, we carefully skirt the very complex and largely em- 

 pirical subject of radiology, as compelling and as intrinsically interesting as 

 the subject matter may be. 



Within a few years after 1895, many effects of X rays on adult humans 

 had been observed, and others imagined and foreseen. The early workers, 

 and their patients, suffered from skin burns, some radiation sickness, warts, 

 deformed fingers, loss of hair; and finally the onset of various forms of cancer 

 (Figure 9-1). 



234 



