An evaluation of radio frequency exposure from therapeutic diathermy equipment

To assess the physiotherapist's exposure to radio frequency electromagnetic fields (RF) leaking from short wave diathermy equipment, we conducted on-site measurements of stray electric and magnetic fields (27.12 MHz) close to continuous wave (CW) short wave equipment. The results show that the operator's knees may have the highest exposure level for both electric field (E-field) and magnetic field (H-field) in the normal operating position, i.e., behind the device console. The whole-body E-field exposure normally does not exceed the 1992 IEEE recommended limit during a normal treatment session. On the other hand, the operator's whole-body exposure to H-field was barely below the recommended limit. Our data suggest little chance of immediate harmful effects of RF leakage from the diathermy. Nonetheless, physiotherapists should still be advised to remain at a distance of at least 20 cm from the electrodes and cables to avoid possible overexposure.