264. Transcranial magnetic stimulation: Actual exceeding of exposure limits for operators. (December 2018)

• Record Type: Journal Article
• Authors: Frigerio, F.; Toma, V.
• Is Part Of: Physica medica. Volume 56(2018)Supplement 2
• Page Start: 224
• Publication Date: 2018-12
• Subjects: Medical physics -- Periodicals; Biophysics -- Periodicals; Biophysics -- Periodicals; Imagerie médicale -- Périodiques; Radiothérapie -- Périodiques; Rayons X -- Sécurité -- Mesures -- Périodiques; Physique -- Périodiques; Médecine -- Périodiques; 610.153
• DOI: 10.1016/j.ejmp.2018.04.274
• Languages: English
• ISSNs: 1120-1797

Abstract

Abstract : Purpose: To show that Transcranial Magnetic Stimulation (TMS)[1] causes exposure of the operators to pulses of magnetic fields above action levels established for workers. TMS is actually a major source of exposure even if poorly, if not at all, considered even among possible risks for implanted device bearers[2] . Methods: Magnetic flux density at different ranges from the stimulation coil was measured in different clinical environments. A Narda Exposure Level Tester ELT 400 was coupled to a Digital Storage Oscilloscope in order to record the pulse shape in the time domain. In post processing, the spectra of the different pulse shapes have been obtained by FFT analysis. Results: Action values established for workers, are exceeded within 1 meter from the stimulation coil, depending on coil shape and orientation, with respect to the operator's body. Safety limits for implanted devices that can undergo Magnetic Resonance Imaging are easily exceeded as well. Conclusions: Despite health effects to clinical staff due to the use of TMS are not reported, action values established for workers and, as reported in literature, even exposure limits, are exceeded. A different design of the stimulating system and the use of shielding based on the self-induced magnetic field are therefore suggested.