HIGH ENERGY IRRADIATION: BIOELECTRIC EFFECTS 



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2 4 6 8 10 



Hours for non-irradiated nerves 



Fig. 5. Nonirradiated control nerves exhibit a variation in the amplitude of the 

 spike potential when plotted as percentage of the initial spike potential. 



024 680 12 14 



Hours after deuteron irradiation 



Fig. 6. The time course for the inhibition of the spike potential of nerves bom- 

 barded with 455 Mev deuterons in the dose range 50 to 300 krad is pictured. Altera- 

 tions in the magnitude of the action potentials are given in terms of relative spike 

 activity, i.e., percentage of the initial spike potential. 



deterioration of spike potential activity, but the degree of impairment was 

 mimicked by the nonirradiated controls. The slope of the alpha particle dose- 

 survival line is double that of the deuteron line (Fig. 7). This alpha particle- 

 deuteron slope ratio is taken as evidence that alpha particles have twice the 

 relative biologic efTectiveness of deuterons. 



Conduction velocities of propagated impulses have been computed from 



