Investigation of a Lorentz force biomagnetometer

• Published in: IEEE transactions on biomedical engineering Vol. 44; no. 6; pp. 455 - 461
• Main Author: Towe, B.C.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.06.1997; Institute of Electrical and Electronics Engineers
• Subjects: Biological and medical sciences; Biothermics. Biomagnetism. Bioelectricity; Current measurement; Electromagnetic Fields; Equipment Design; Evaluation Studies as Topic; Force measurement; Fundamental and applied biological sciences. Psychology; Image Processing, Computer-Assisted; Image reconstruction; Immune system; Instruments; Lorentz covariance; Magnetic field measurement; Magnetic moments; Magnetics; Microscopy; Noninvasive treatment; Sensitivity and Specificity; Tissues, organs and organisms biophysics; Sensitivity analysis; Magnetometers; System design; Ionic current; Image reconstruction; Biological system; Magnetic field effect; Biomedical data processing; Low current; Non invasive method; Lorentz force; Measurement method; Technique; Signal to noise ratio
• ISSN: 0018-9294; 1558-2531
• DOI: 10.1109/10.581933

This work evaluates an approach to the noninvasive measurement of small ionic current flows by a technique of Lorentz force magnetometry. An instrument was constructed that is basically a very sensitive force-balance that can measure Lorentz forces experienced by ionic currents flowing in small objects when exposed to strong oscillating magnetic fields. For objects that can fit on a microscope slide, the system is sensitive to ion current dipole moments as low as 180 pA-m. Images were made of ionic currents flowing in thin profiles by a process of scanning a localized magnetic field over the object, measuring generated Lorentz forces, and using a computer to reconstruct images. It can be shown that this method of Lorentz magnetometry has an immunity to ambient magnetic noise and has system characteristics that might suggest its possible use in biomagnetometry of small thin specimens.