An evaluation of the collateral influence of a pulsed electromagnetic field emitted by physiotherapeutic devices

The physiotherapeutic use of the pulsed electromagnetic field (PEMF) leads to exposure of patient and any object. Different rules of assessing the influence on humans and electronic devices need to be implemented. The aim was to study the parameters of PEMF emitted by widespread physiotherapeutic devices with respect to the health hazards caused by exposure: by experimental analysis of PEMF waveform and by investigation of the spatial distribution of electric and magnetic field strengths near physiotherapeutic applicators emitting PEMF of the lowest duty factor (Salus Talent, Thermopulse). PEMF was evaluated with respect to root-mean-square (RMS) values averaged in time, or over the pulse duration only, and compared against the limits imposed for the safety of human exposure (general public or workers) and of using electronic medical implants. In measurement results (of RMS value over the pulse duration even exceeding 10-times the RMS values measured over time), the insufficient respond of measuring devices to PEMF (responding not sufficiently fast to pulsed signals, and not sufficiently sensitive to signals of a low duty factor) may reduce measurement results even over 10-times. This may cause a significant underestimation of the hazards caused by PEMF near physiotherapeutic devices (up to 1-2 m from applicators).