• Contactless method of lungs contamination measurement;
• Active electrodes for multichannel biosignal measurement.

Result 1: Contactless method of lungs contamination measurement

Project: APVT No. 51-017802

Investigators: A. Cigáň, K. Jurča, P. Jurdák, J. Maňka, F. Martinická, I. Šimáček, V. Zrubec

Applicator: Institute of Occupational Medicine an Toxicology, Faculty Hospital, Bratislava

We have designed a contactless non-invasive method of determination of the ferromagnetic contaminant component deposited in the lungs tissue and breathing pathways. Using the SQUID magnetometric system and by computation of the remanent magnetic induction of magnetized ferromagnetic microparticles it is possible to determine their mean concentration.

The method is based on mathematical modeling the volume, shape and position of the lungs with automatic correction of the data regarding to some anatomical and physiological properties of the measured part of body. For adult man it is possible to detect the powder Fe₃O₄ in his lungs even at mass concentration ~20 mg/cm³.

In clinical praxis this method offers prompt data in diagnostics of lung fibrosis and welder's pneumoconiosis.

In the figure there is an comparison of measured magnetic signals from the left lung in control (healthy person) (1) and in welder with contaminated breathing pathways (2).

Publications:

• F. BOHÁKOVÁ, I. ŠIMÁČEK, P. JURDÁK: Basic quantification of magnetic particles in solid substance and human tissue by the SQUID magnetometer. Sensors and Actuators, A 129 (2006) 150-153.
• F. MARTINICKÁ, I. ŠIMÁČEK, P. JURDÁK, A. CIGÁŇ, J. MAŇKA: SQUID method of lung contamination testing. Physica C, 435, (2006) 128-131.

Result 2: Active electrodes for multichannel biosignal measurement

Project: APVV-51-059005 „Use of magnetic and electric measuring methods for noninvasive examination of the liver and heart“

Authors: V. Rosík, A. Kulišov, M. Tyšler

Applicator: Faculty of biomedical Engineering, Czech Technical Univesrity in Prague

New construction has been proposed and active electrodes with thermally compensated amplifier, high input and very low output impedance have beeen realized using SMD technology. The electrodes are intended for use in multichannel biomedical measuring systems with high requirements for suppression of disturbing signals and patient safety and hygiene. Use of the electrodes significantly reduces interference from the power lines induced in electrode cables even if the electrode contact impedance is high. This fact enables to use the electrodes without abrasive skin preparation. Low output impedance of the electrodes minimizes the triboelectric interference generated during the mechanical deformation of isolation layer of the lead cables what is important when recording signals from moving objects (e.g. excercise ECG).

Original electromechanical solution in the form of miniature active adapters with standard snap for connection of single-use pre-gelled passive Ag-AgCl electrodes guarantees low noise, minimal polarization potentials and outstanding DC stability. operating costs are practically the same as for passive electrodes. Interchangeability and fast application of electrodes eliminates the risk of infections and minimizes the patient uncomfort.

In the figure there is an active electrode consisting of a passive commercial Ag-AgCl electrode, an active adapter with a built-in amplifier and a multiwire cable.

Publications:

• TYŠLER M. – ROSÍK V. – KNEPPO P.: Multichannel ECG Measurement for Noninvasive Identification of Heart Regions with Changed Repolarization. In: Proceedings of the XVIII IMEKO World Congress, Congrex do Brasil, 2006 (CD).
• KNEPPO P. – ROSÍK V. – TYŠLER M. – KARAS S. – HÁNA K. – SMRČKA P. – JULÉNY A.: High Resolution ECG Mapping System for Noninvasive Cardiac Diagnostics. IFMBE Proceedings, 2006, Vol. 14, 2006, 1171-3374. ISSN 1727-1983.