REPORT OF THE 

 COMMITTEE ON PATHOLOGIC EFFECTS 



The Committee on Pathologic Effects of Atomic Radiation and its Subcommittees, since the 

 publication of their report of June, 1956, have been reviewing all available data pertinent to 

 the field. The Committee is grateful to the United States Atomic Energy Commission, the De- 

 partment of Defense, the United States Public Health Service and numerous investigators for 

 providing pertinent data. 



This report is essentially similar to our last Summary Report. Appendices will be pub- 

 lished by several of the Subcommittees during the next few months bringing up to date the 

 data in their appropriate fields of competence. In presenting this report, it has seemed best for 

 completeness to republish much of the original report, with the additions and emendations to 

 that report shown in italics. Some omissions have been made in the original report to improve 

 brevity and clarity. 



Appreciation of the pathologic effects of radiation on man has required of this Com- 

 mittee and its Subcommittees consideration of voluminous experimental work on animals, as 

 well as such direct data on human beings as are available. When the results of controlled ex- 

 perimental studies are considered in the light of the human data, it is found that the sequence 

 of pathological changes is indeed quite similar in man and in animals, although man has cer- 

 tain definable peculiarities of response, as have some other species. Therefore, not all experi- 

 mental data on animals are directly transferable to man. 



The human data include: 



Results of excessive exposure to X-rays and radium in the early days; 



Results of more moderate exposure to different forms of radiation, as experienced by 

 cyclotron workers; 



Results of introduction of naturally occurring radioelements into the body, notably 

 radium preparations and thorotrast; 



Effects of exposure at Hiroshima and Nagasaki; 



Observations on populations irradiated by fallout; 



Additional observations from clinical radiotherapy, use of artificial isotopes in therapy, 

 a very limited number of accidents in atomic energy work, and certain statistical surveys of 

 large groups. 



Experimental work covers the whole field and includes studies of acute and chronic ef- 

 fects on many species of animals. 



Certain human effects have to be assumed from consideration of experimental knowl- 

 edge (for example, early effects of high doses to the central nervous system, and results of 

 absorption of most of the artificially produced isotopes) and it is fair to say that the lethal 

 dosage of penetrating radiation for man is less well known than for many other species. 



Radiation has been added to the means of production of casualties in warfare. Not only 

 can radiation cause death or immediate or delayed injury by itself, but exposure to it intensifies 

 the seriousness of thermal burns or other injuries. The acute lethal dose of whole body radia- 

 tion for half of a given population is in the range of 400 to 600 r. 



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