Electrical conductivity interfaces scanning by ultrasonically-induced Lorentz force

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HAL Id: hal-02066783

https://hal.archives-ouvertes.fr/hal-02066783

Submitted on 13 Mar 2019

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Electrical conductivity interfaces scanning by

ultrasonically-induced Lorentz force

A. Montalibet, J. Jossinet, A. Matias

To cite this version:

A. Montalibet, J. Jossinet, A. Matias. Electrical conductivity interfaces scanning by ultrasonically-induced Lorentz force. 2nd European Medical and Biological Engineering Conference EMBEC’02, Dec 2002, Vienna, Austria. �hal-02066783�

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ELECTRICAL CONDUCTIVITY INTERFACES SCANNING

BY ULTRASONICALLY-INDUCED LORENTZ FORCE

A. Montalibet, J. Jossinet, A. Matias

INSERM U556 - 151 cours Albert Thomas, 69424 Lyon cedex 03, France

Tel : +33 (0)4 72 68 19 48 Fax : +33 (0)4 72 68 19 31 E-mail : montalibet@lyon.inserm.fr

1. DESCRIPTION

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Tissue characterisation associating the discrimination ability of bioelectrical measurements

and the spatial resolution of ultrasound.

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Advantages : low-cost, bio-compatibility, harmlessness, non-invasiveness, new modality.

2. FUNDAMENTALS

3. APPLICATION

Horizontal magnetic field Longitudinal ion oscillation

Vertical ion deviation due to Lorentz force

Ä Bulk current density

Focused ultrasound: 2 MPa, 500 kHz, 6 µs Permanent magnet NdFeB: 0.35 Tesla Current-to-voltage converter: G=80000 V/A

4. RESULTS

5. CONCLUSIONS

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The proposed new modality enabled the 1-D scanning of conductivity interfaces in physical

models and layered biological samples.

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Further work includes improvement of signal processing, 2-D scanning, wide-band

measurements and adaptation to existing devices.

This works was partly supported by the Medical Research Foundation (FRM)

gel electrodes 2 cm

gel electrodes

2 cm

Purpose-built

magnet Current sensing

1. input interface 2. skin → fat 3. fatty layer 4. fat → muscle 5. muscle → fat 6. embedded muscle 7. embedded muscle 8. output interface 1 ₂ 3 4 5 6 7 8 1 ₂ 3 4 5 6 7 8 (Oz) vr ) (Oy FL r ) (Ox Br current sensor electrode w = 3 cm L = 9 cm I 45 mm 0.35 T 45 mm 0.35 T Experimental set-up

CONDUCTIVITY INTERFACES IN A LAYERED BIOLOGICAL SAMPLE

TYPICAL SIGNALS IN AGAR GEL MODELS

pressure gel blocks ( σ in S/m ) raw signal after Wiener filtering 0 1.4 0 0 0.5 1.4 0