Susceptibility Bridge Magnetopneumography of Individuals With and Without Occupational Dust Exposures

摘要

A survey of the recent progress in remanent field magnetopneumography of welders exposed to ferromagnetic contamination reveals the need for additional measurement techniques and reassessment of the utility of the method. The design of a new alternating current susceptibility bridge, proposed for supplemental screening, is presented together with the results of a pilot study on individuals with occupational dust exposure and a control cohort. Initial clinical measurements demonstrate that nonexposed males show a net diamagnetic signal equivalent to that expected from a thoracic content of 25 kg water. Welders show an average net diamagnetic signal apparently reduced by contamination from approximately 30 mg ferromagnetic material. A small fraction of the control population shows an anomalously large net diamagnetic signal, as do seven out of eight asbestosis/silicosis patients with 100% disability and no ferromagnetic contamination. The implications of these findings are discussed in terms of possible exogenic and endogenic sources of excess magnetic material, i.e. occupational dust exposures and the iron storage disorders. (Copyright (c) by The Danish Welding Institute, 1982.)