6 BIOLOGICAL EFFECTS OF ATOMIC RADIATION 



to provide an essential part of the information needed by geneticists for the estimates they are 

 expected to make. 



A large and important area in which progress is being made at present and in which much 

 more can be done in the immediate future is that of reducing human exposure to man-con- 

 trolled radiation, including that from diagnostic and therapeutic medical radiation; that from 

 industrial and other peacetime uses of nuclear energy; and that arising from development, 

 testing, and use of nuclear devices. Although a consideration of how further reductions in 

 exposure to radiation from such sources can most effectively and quickly be brought about lies 

 largely outside the competence and assignment of this Committee, we nevertheless regard it as 

 desirable and proper to urge that those who possess the requisite knowledge, persuasiveness, 

 and authority continue to take all reasonable steps in bringing about such reduction as 

 rapidly as possible and to the lowest practicable levels. 



In this connection, it is noteworthy that the International Commission on Radiological 

 Protection, in its latest report, has suggested a three-fold reduction of the maximum permis- 

 sible gonad doses for occupational exposure. It has also recommended a maximum permis- 

 sible genetic dose for the population in line with this Committee's recommendation of 1956, 

 but in greater detail to provide additional safeguards. Also, the American College of Radiol- 

 ogy has initiated an educational campaign to reduce the gonadal doses received by patients 

 from diagnostic and therapeutic procedures. 



It is the purpose of the present report to supplement the earlier report of this Committee 

 in two ways: ( 1 ) by indicating some of the specific areas in which additional knowledge 

 appears to us to be necessary for the desired refinements in estimates of probable genetic 

 damage from radiation, and (2) by suggesting ways in which attainment of this knowledge 

 can be expedited. 



In indicating specific areas in which further research is needed. Committee members 

 hope that the development of novel and more imaginative approaches will not be discouraged. 

 We are well aware that some of the most important discoveries in the future will almost surely 

 come from unexpected directions instead of from areas of research that can now be seen 

 clearly. Nevertheless, since there are obvious gaps in our present knowledge that can be filled 

 by application of existing or readily foreseeable methods, we have prepared this account of the 

 major areas of needed investigation as seen from our present viewpoint. 



III. What We Need To Know 



The essential problems are: What are the characteristics and magnitude of the genetic 

 effects of ionizing radiation on man, how important are these effects, and how can they be 

 avoided or mitigated? 



In order to characterize and better define present estimates of the magnitude of radiation- 

 induced effects, further information will also be needed about the occurrence of spontaneous 

 mutations and those caused by agents other than radiation. In order to assess radiation effects 

 with more accuracy, we need to know more about the breeding structure of human popula- 

 tions, the detailed working of selection in them, and the effects of modern hygiene and thera- 

 peutic procedures. It will be necessary to answer many related questions about the somatic 

 effects on man of radiation and other agents. We must learn more about the genetics of or- 

 ganisms other than man and about the effects of radiation on them. This is so because in 



