THE RELATION OF FREQUENCY TO THE PHYSIOLOGICAL EFFECTS OF ULTRA-HIGH FREQUENCY CURRENTS
RONALD V. CHRISTIE, ALFRED L. LOOMIS · 1928
This 1929 study found that ultra-high frequency currents killed mice through heat production, with lethality proportionate to field intensity up to about 50,000,000 cycles.
Plain English Summary
This 1929 research by Christie and Loomis exposed mice to ultra-high frequency radiation at frequencies between 1,000,000 and 158,000,000 cycles per second (wavelengths from 300 meters to 1.9 meters) and measured lethal effects and heat production. The lethal effect was proportionate to the intensity of the field up to about 50,000,000 cycles (6 meters wavelength), and at higher frequencies both heat production and lethality diminished. The lethal effect was fully accounted for by heat production, strictly analogous to diathermy.
Why This Matters
This research is an early systematic investigation into how frequency affects the lethal effects of ultra-high frequency currents, using mice exposed to a vacuum tube oscillator. Published in 1929, Christie and Loomis found that the rate of heating in live mice averaged 1.95°C, 1.88°C, and 2.55°C per minute at 36.1, 14.0, and 6.0 meters, with dead mice showing similar heating rates. The lethal effect could be fully accounted for on the basis of heat production, and the results do not suggest any specificity with regard to the action of particular wave-lengths on living cells. What this means for you is that frequency matters when evaluating how much current is induced in tissue: the apparent lethality of the radiation decreased at very low wave-lengths because less current was induced in the mouse.
Figures from the Original Paper
Diagrams extracted from the original research document.
Exposure Information
Specific exposure levels were not quantified in this study. Duration: 3-5 minutes at 6.0-36.1 meters, 6-12 minutes at 3.2 meters, 8-13 minutes at 1.9 meters
Study Details
To investigate the relationship between frequency and physiological effects of ultra-high frequency currents, specifically examining lethal effects and heat production in mice at various frequencies.
Mice were exposed to ultra-high frequency radiations from a vacuum tube oscillator operating at freq...
The lethal effect of the radiations was found to be proportionate to the intensity of the electromag...
The lethal effect of ultra-high frequency currents can be fully accounted for on the basis of heat production. The production of heat is strictly analogous to that observed in diathermy, being generated by the resistance and dielectric loss in tissues. The results do not suggest any specificity exists with regard to the action of particular wave-lengths on living cells. The apparent lethality of the radiation decreases at very low wave-lengths due to less current being induced in the mouse, which can be explained by changes occurring in the dielectric properties of tissues at low wavelengths.
Show BibTeX
@article{the_relation_of_frequency_to_the_physiological_effects_of_ultra_high_frequency_c_g5533,
author = {RONALD V. CHRISTIE and ALFRED L. LOOMIS},
title = {THE RELATION OF FREQUENCY TO THE PHYSIOLOGICAL EFFECTS OF ULTRA-HIGH FREQUENCY CURRENTS},
year = {1928},
}