206 BIOLOGICAL EFFECTS OF RADIATION 



Flesh Transmission. — The transmission curve of a 5.0-mm. thickness of 

 flesh determined by Cartwright (17), and corrected for reflection by 

 Forsythe and others, is shown by the full-Une curve F in Fig. 36. A 

 thermocouple-filter combination, yielding a very similar curve, is offered, 

 shown by the dotted Curve C. Such a detector should be useful in 

 determining the effectiveness of sources in raising the temperature of 

 underlying tissue. It should not be assumed, however, that this is a 

 measure of therapeutic value. . 



The reliability of measurements of this general type can be no greater 

 than the reliability of the observations of the biological effect. If the 

 response curve of the detector departs markedly from the relative 

 effectiveness of equal energy in producing the specified biological phe- 

 nomenon, the results may be wholly misleading. We therefore urge 

 great care in the application of selective detectors, such as has been 

 illustrated in this chapter. 



In the course of this discussion, we have attempted to outline sound 

 procedure, to offer a convenient assembly of pertinent data, and to 

 emphasize the many sources of difficulty encountered in radiation 

 measurements. 



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