CHAPTER 14 



The Pathological Physiology of Radiation Injury 



in the Mammal. I. Physical and Biological 



Factors in Radiation Action 



Harvp:y M. Patt and Austin M. Brues 



Division of Biological and Medical Research, Argonne National Laboratory, 



Lemont, III. 



Introduction. Nature of the biological response to radiation. Radiation quality and 

 quantity. Biological factors in radiosensitivity: Cell and tissue sensitivity — Species 

 sensitivity — Individual sensitivity. Induced radiosensitivity or resistence: Temperature 

 and metabolic rate — Intermediary radiochemical events. Summary. References. 



INTRODUCTION 



When in 1895 Professor Rontgen reported on a "new form of radiation " 

 to the Wurzburg Physico-Medical Society, the stage was set for an 

 energetic, though initially somewhat chaotic, development in biology. 

 The discovery of radioactivity by Becquerel in 1896 lent further impetus 

 to this development, although the connection between the two forms of 

 radiation was not immediately apparent. Alopecia following X-ray 

 photography was reported by Daniel (1896) four months after Rontgen's 

 announcement, and the severe superficial injuries of a journeyman 

 exhibitor of X-ray machines were eloquently described in the August 12, 

 1896, issue of the Electrical Review. Radiation dermatitis and epilation 

 were observed by Leppin (1896) and Stevens (1896) at about the same 

 time. In 1897, Freund reported the successful removal of a hairy mole 

 with X rays, and Walsh described the unpleasant symptoms of acute 

 radiation illness. Two years later a report on treatment of skin cancer 

 with X rays appeared (Stenbeck, 1899), and in 1902 the earliest case of 

 radiation-induced cancer was recorded (Frieben). Perhaps the first 

 observation of an internal effect may be attributed to Senn, who described 

 a decrease in size of the spleen in 1903. 



As a consequence of these observations and the pressure of growing 

 clinical usage, the biological action of ionizing radiation on animals and 

 man was widely studied, and, although the experiments took place 

 sporadically, with great variation in methods of exposure and dosage, 

 many fundamental facts soon emerged. Among these were the selective 



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