PREFACE 



Radioisotope technitjues, to the naive, may represent the panacea for 

 investigational difficulties — the royal road to successful experimentation ; 

 to the cynic they may appear as gadgetry, a fad that creates more prob- 

 lems than it solves. As always, the truth lies somewhere between the 

 extremes. The really important contributions of these procedures in the 

 biological field will be realized only insofar as they are utilized by investi- 

 gators who are well grounded and have been working in the field of appli- 

 cation. This is not to belittle the physical scientist, whose tremendous 

 contribution is acclaimed by all. Nevertheless it is the biologist who 

 recognizes the important problems in his own field, is famiUar with 

 the experimental material, and must be counted upon to make the 

 interpretations. 



A primary purpose of this volume is to bring home to the student and 

 investigator an appreciation and understanding of how radioisotopes can 

 fit into his program, and then to show how the experimental work can be 

 undertaken. Chapter 1 presents certain basic principles unobscured by 

 considerations of nuclear physics and experimental details. These prin- 

 ciples are illustrated by examples drawn from such diverse fields as 

 physiology, nutrition, entomology, and soils and fertilizers. The section 

 on kinetics may be difficult for the reader with no background in mathe- 

 matics, but an understanding of logarithms will enable him to use the 

 methods. To follow the derivations will require some little knowledge of 

 calculus. 



Chapter 2 deals with certain difficulties inherent in tracer studies, 

 describes the pitfalls, and attempts to show how they may be recognized, 

 avoided, or taken into account in the interpretations. Chapter 3 is con- 

 cerned with the practical problems of health physics and introduces the 

 various units and physical concepts that are necessary for work with 

 radioactive materials. Chapters 4 and 5 describe the facilities required 

 and procedures suitable for studies with plants, laboratory animals, and 

 domestic animals. Although it is recognized that methods and instru- 

 mentation have been improving rapidly, it seems that the approach is now 

 fairly standard and that it is of value to know which methods have proved 

 to be adequate in use. Rather than attempt to describe all the proce- 



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