THERMAL CHANGES PRODUCED IN TISSUES BY LOCAL APPLICATIONS OF RADIOTHERAPY
CAROL B. PRATT, CHARLES SHEARD · 1935
1935 research documented early evidence of how radiofrequency energy heats biological tissues through diathermy applications.
Plain English Summary
This 1935 study examined how short wave diathermy (radiofrequency energy used for medical heating) changed temperatures in animal tissues. The research measured thermal effects when RF energy was applied locally to biological tissues, contributing early evidence about how electromagnetic fields create heating in living systems.
Why This Matters
This research represents some of the earliest scientific documentation of how radiofrequency energy heats biological tissues. While conducted for medical applications, the findings established fundamental principles that remain relevant today. The thermal effects measured in this study occur through the same basic mechanism that heats food in your microwave oven and warms tissue near your cell phone during calls. What makes this historical research particularly significant is that it predates our modern understanding of non-thermal EMF effects by decades. Today we know that biological systems can respond to RF energy at levels far below those that cause measurable heating, yet thermal effects remain the primary basis for current safety standards.
Finding
The average intra-articular temperature rose 2.5°C. but remained below the rectal temperature. These temperatures dropped sharply after cessation of the treatment. When thermocouples were inserted after application of the electric field, the intra-articular temperature rose about 1°C. and dropped very slowly with time, whereas the subcutaneous temperature, apparently was not affected by the treatment.
In their words
“The average intra-articular temperature rose 2.5°C. but remained below the rectal temperature. These temperatures dropped sharply after cessation of the treatment. When thermocouples were inserted after application of the electric field, the intra-articular temperature rose about 1°C. and dropped very slowly with time, whereas the subcutaneous temperature, apparently was not affected by the treatment.”
Figures from the Original Paper
Diagram extracted from the original research document.
Exposure Information
Specific exposure levels were not quantified in this study. Duration: 1-2 minutes
Study Details
To evaluate thermal changes produced in tissues by local applications of high frequency electric fields and to determine the effects on intra-articular and subcutaneous temperatures in dogs.
Thermocouple needles were inserted into intra-articular and subcutaneous tissues of dogs' knee joint...
Intra-articular temperatures rose significantly above rectal temperature (31.5°C to 36.1°C) during t...
Local applications of high frequency electric fields produce significant heating in deep tissues (intra-articular) but minimal heating in superficial tissues (subcutaneous) during short duration treatments. The depth of heating is dependent on the distance between the field plates and the tissue surface. The thermal effects are primarily due to the high frequency field energy rather than direct contact heating.
Show BibTeX
@article{thermal_changes_produced_in_tissues_by_local_applications_of_radiotherapy_g5924,
author = {CAROL B. PRATT and CHARLES SHEARD},
title = {THERMAL CHANGES PRODUCED IN TISSUES BY LOCAL APPLICATIONS OF RADIOTHERAPY},
year = {1935},
}