CHAPTER 24 



GENERAL CRITIQUE OF THE BIOLOGICAL APPLICATION 



OF ISOTOPES 



Ellsworth C. Dougherty 



24.1. Introduction. The object of Part III of the present volume is to 

 supply information on the significance of stable isotopes and artificial radio- 

 active isotopes in biology and medicine. This, of course, nowhere nearly 

 exhausts the application of physical phenomena to biological and medical 

 research. However, it is not proposed that this section be a comprehensive 

 review of biophysics. It is rather designed as a reference source for biologists 

 who propose to employ isotopes as tools in their work. To that end the 

 biological literature in which the use of isotopes is recorded has been com- 

 prehensively surveyed and a bibliography prepared (initially in collaboration 

 with M. C. Fishier), which is appended as Chap. 30. From the literature 

 representative studies that illustrate the major applications of the isotopes 

 already used have been selected for purposes of brief discussion. Tables of 

 these isotopes (Tables 46 and 47) have been prepared, which list their major 

 applications to date. A further table (Table 48) lists those isotopes which, 

 on the basis of present evidence, have potential usefulness in biological and 

 medical work. Part III is subdivided as follows: (1) the introductory chapter 

 in which is presented a critique of the biological and medical application of 

 isotopes; (2) several chapters (Chaps. 25 to 28) in which the elements, 

 arrayed generally according to their biological significance, are considered 

 and the use of their isotopes is discussed; (3) a chapter (29) on isotopes in 

 medical therapy and diagnosis; and (4) the bibliography (Chap. 30). 



It is intended that, guided by the general remarks of Chap. 24, the investi- 

 gator who desires to use an isotope to solve a given problem will be able, 

 with the use of Tables 46, 47, and 48, the discussions of Chaps. 25 to 29, the 

 bibliography, and relevant chapters in Parts I and II of the present volume, 

 to determine whether an appropriate isotope may exist for this problem. 

 If in practice this aim is realized, the author will consider the purpose of 

 his section fulfilled. 



Consideration of the isotopes of the three naturally radioactive series 

 has been largely omitted here for two principal reasons: (1) because the 

 literature is extensive and voluminous, extending back to the beginning of 

 this century and thus imposing an inordinate expenditure of time and effort 



503 



