Measurements of the magnetic fields produced by the human heart, brain, and lungs

Magnetic fields produced by organs of the human body are being measured in the M.I.T. shielded room, using both a SQUID magnetometer and second-derivative gradiometer. Measurements of the field around the human body can yield new information about the organs which generate current, not available to surface electrodes, and also about organs which contain foreign, ferromagnetic particles. Magnetocardiograms of normal and abnormal heart subjects are being analyzed and visually displayed in order to assess their information content. Magnetoencephalograms recorded from normal and abnormal brain subjects are also under analysis. Measurements have been made of magnetite dust in the lung, with two potential medical applications: the first is the use of pure magnetite dust as a deliberately inhaled tracer (harmless) for pulmonary diagnosis; the second is the assessment of the amount of asbestos accumulated in the lungs of heavily-exposed workers, since most asbestos (harmful) occurs with adhered magnetite.