Reduction of radiofrequency exposure to the operator during short-wave diathermy treatments.

Radiofrequency electromagnetic fields near short-wave diathermy equipment operating at a frequency of 27.12 MHz can expose the physical therapist to levels above those recommended in standards for radiofrequency exposure in Western countries. Electric and magnetic fields around air-gap, diplode, monode and circuplode applicators were mapped by the author. Large differences in stray field intensities were found for the various applicators. The air-gap electrodes caused the highest levels of unwanted radiation, and the circuplode caused the lowest levels. The use of the circuplode would normally ensure an operator exposure far below the levels in recommended standards. In order to reduce the exposure during the first few minutes of a treatment, when air-gap electrodes or diplode are used, the operator should stand at the end of the diathermy console opposite to the applicator and cables and not, as is often the case, at one side. It is recommended that manufacturers change the design of the diathermy console (a minor modification) in order to ensure this operating position.