1148 RADIATION BIOLOGY 



because the radioactive material is not uniformly distributed and neo- 

 plastic transformation may occur at points of greatest density of the 

 radioactive material. 



The maximum permissible amount of a radioactive element in micro- 

 curies fixed in the body of man as revised in "International Recommenda- 

 tions on Radiological Protection" (1951) is as follows: Ra 226 , 0.1; Pu 239 , 

 0.04; Sr 89 , 2.0; Sr 90 ( + Y 90 ), 1.0; Po 210 , 0.005; H 3 , 10; C 14 (as carbon 

 dioxide in air), none; Na 24 , 15; P 32 , 10; Co 60 , 1; I 131 , 0.3 (0.18 in thyroid). 

 Additional data on these elements, such as effective mean life, permissible 

 daily deposition in body, proportion absorbed via lungs and retained in 

 the body, proportion retained after absorption from the gut, and maxi- 

 mum permissible level in liquid media and in air are listed. 



HISTORICAL 



The first published account of the injurious effects of X irradiation, 

 such as dermatitis and alopecia, was made in 1896 by Marcuse. Soon it 

 became apparent that these skin lesions are excruciatingly painful, slow 

 to heal, and likely to break down and terminate in cancer. 



The dramatic sequence of events leading to carcinoma from exposure to 

 X radiation is well recorded by Hall-Edwards in his autobiographical 

 notes (1904, 1906) which will be read with interest and respect by those 

 interested in the history of science. 



Hall-Edwards commenced his clinical research a few weeks after 

 publication of Roentgen's discovery. In 1896 he gave a series of demon- 

 strations in fluoroscopy, on each occasion exposing his hands for several 

 hours. A primitive X-ray tube in operation is shown in Fig. 18-1 and the 

 wide-open exposure of the fluoroscopist is evident. Some two or three 

 weeks after exposure, Hall-Edwards noticed that the skin around the 

 roots of the nails was red and painful. Thus commenced the lesions 

 described objectively in their full tragedy in his first communication in 

 1904. During the subsequent two years he did "not experience a 

 moment's freedom from pain . . . and was rendered absolutely incapable 

 of work, either mental or otherwise." On the back of each hand fifty to 

 sixty warts appeared, many of them confluent.. In 1908 his forearm was 

 amputated, and he died in 1926. "As far as I know of all that early band 

 of workers who persisted in practicing Radiography, he is the only one 

 who escaped death from malignant disease" (Barling, 1926). 



The first cancer arising in radiologists was described by Frieben (1902) 

 and Sick (1903), who made the diagnosis, and the next by Lloyd (1903). 



The first American martyr of X irradiation was Clarence Madison 

 Dally, an assistant of Thomas A. Edison in research on the fluoroscope. 

 Seven years after the first exposure in 1896 he developed a cancer at the 

 site of an X-ray ulcer of the hand. This was not controlled by amputa- 



