Basic quantification of magnetic particles in solid substance and human tissue by the SQUID magnetometer

The present study concerns an rf SQUID magnetometer enabling to measure magnetic fields of order 2 × 10−14 T Hz−1/2 and its utilization for the detection and quantification of particles with magnetic properties in different materials and human tissue. In the first case, the mass concentration np of powdered ferro- and ferrimagnetic material (PFM) in a physical model with known shape, volume and PFM content was estimated in order to evaluate the uncertainty of the method. Secondly, the lungs of an arc welder who was long-term exposed to welding fumes were examined. The mean np of 0.0845 mg cm−3 of ferromagnetic dust with the mass ratio of Fe:Ni materials 99.12%:0.82% and the specific remanent magnetic moment mrs of (0.127 ± 0.076) A m2 kg−1 was found.