Safety of the magnetic field generated by a neuronal magnetic stimulator: evaluation of possible mutagenic effects.

Objective: The possible mutagenicity of a magnetic stimulus was checked using the Ames test with Salmonella typhimurium TA98 and TA100 as tester strains.

Methods: Samples of these bacteria were exposed to a pulsed magnetic field, on the order of 1 T. The magnetic pulses were generated by a neuronal magnetic stimulator with a flat coil. The magnetic stimulus was a continuous sequence of slightly damped half sinusoids at a rate of 5 pulses/s. Exposure times were 2-5 and 15 min. Exposure position was such as to maximise the magnetic field and minimise the induced electric field. Room temperature was maintained at 28.5 +/- 0.5 degrees C and the temperature was measured inside the samples.

Results: None of the exposure conditions showed any increase in mutation in either of the two bacterial strains.

Conclusions: These results are discussed in comparison with effects found in the literature. The magnetic stimulation used under the conditions of this study does not appear to have mutagenic effects. This does not apply to cases where both strong electric and magnetic fields are present.