Electrical impedance imaging at multiple frequencies in phantoms
| Autor: | K. Sunshine Osterman, Todd E Kerner, Dinsie B Williams, Keith D. Paulsen, Alex Hartov, Fred R Reiss |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Permittivity
Materials science Physiology Biomedical Engineering Biophysics Edge (geometry) Imaging phantom Optics Nuclear magnetic resonance Electrical resistivity and conductivity Physiology (medical) Electric Impedance Humans Electrodes Tomography Electrical conductor Phantoms Imaging business.industry Equipment Design Electronics Medical Conductor Evaluation Studies as Topic Electrode business Software Order of magnitude |
| Zdroj: | Physiological Measurement. 21:67-77 |
| ISSN: | 1361-6579 0967-3334 |
| DOI: | 10.1088/0967-3334/21/1/309 |
| Popis: | We have recently built and tested a 32 channel, multi-frequency (1 kHz to 1 MHz) voltage mode system to investigate electrical impedance spectroscopy (EIS) imaging. We completed a series of phantom experiments to define the baseline imaging performance of our system. Our phantom consisted of a plastic circular tank (20 cm diameter) filled with 0.9% aqueous NaCl solution. Conductors and nonconductors of decreasing width (W5: 3.4 cm, W4: 2.54 cm, W3: 0.95 cm, W2: 0.64 cm and WI: 0.32 cm) were positioned at various distances from the tank edge (1 cm, 2 cm, 4 cm and 8 cm). The results suggest that the detection of objects less than 1 cm in width is limited to the first 1 to 2 cm from the tank edge for absolute images, but this depth can extend to 8 cm in difference images. Larger 3.4 cm wide objects can be detected in absolute images at depths up to 8 cm from the tank edge. Generally, conductor images were clearer than their nonconductor counterparts. Not only did electrode artefacts lessen as the frequency increased, but the system's maximum resolution was attained at the highest operating frequencies. Although the system recovered the value of the electrical conductivity at the correct order of magnitude, it tended to smooth out large property discontinuities. The calculated electrical permittivity in these phantom studies was inconclusive due to the presence of electrode artefacts. |
| Databáze: | OpenAIRE |
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