The Radio Knife

Radio Record, Volume III, Issue 45, 23 May 1930, Page 31

The Radio Knife

Surgical Invention RArrIo in America has been adapted : in many. novel and ingenious ways to serve the needs of the people. but in nothing more useful than its recent application to surgery. It has been used to provide a bloodless surgieal instrument in the form of a radio knife, A patent, covering the circuit used to perform the work, was applied for as early as 1919, and the first public demonstrations of the knife were made about five years ago. Today many of the largest hospitals include it among their surgical equip-

ment, as it has proved very adaptable ~ to certain kinds of operations. The radio knife is a high-frequency « function. The circuit used to furnish the rapidly-vibrating impulses is easily recognisable as a transmitting circuit identical with those used for common messages. The difference is in . the fact that the high-frequency currents used in the knife are controlled and directed to the electrodes, which are placed in certain relationships to the human body. In performing a surgical operation the electrode does not actually. come in contact with the flesh. It is kept a fraction of an inch distant, and the high-frequency currents passing from the electrode sear the flesh and separate the tissues just ahead of it. The edges of the flesh are seared to such an extent that the blood is. sealed within, The discovery of the radio knife was accidental. The idea was suggested when it was found that the caps worn by the Navy personnel became hot in the front when worn in the laboratories where high-frequency currents were being generated. The cause was found to be that the metal band across the peak of the uniform caps became heated by the radio-frequency impulses in just the same way as the elements of a vacuum tube are heated when surrounded by a coil carrying a highfrequency current in the modern process of manufacturing wireless valves, The largest manufacturers of wireless sets in America have recently gone into the manufacture of radio’ knives to meet the very extensive demand. Surgeons have given their final approval of the new instrument whick has been described as "the most humane method of surgery that has ever been known."