| Magnetic induction impedance measurement is a new noninvasive detection technique,which by measuring bio-impedance. Magnetic induction impedance measurement has twocharacteristics: One is that it is excited by magnetic field, that can penetrate skull easily;the other one is that its imaging method has strong center sensitivity in imaging region,because of the two characteristics; Magnetic induction impedance measurement has anobvious advantage on diagnosing and monitoring cerebral disease, especially for the brainhematoma and cerebral edema clinical real-time monitoring.Based on the electromagnetic measurement technology, symmetrical single-channelmagnetic induction liquid conductivity measurement system and impedance of headmeasurement system have been designed with SR844. The systems can precisely measurethe electro-conductivity of the target conductor. Major work includes the items as follow:First, electromagnetic tomography theory and electromagnetic measurementtechnology are studied. By analyzing the popular system models, a systematicexcitation-detection dual side dual coil model is confirmed. Then, Based on the lock-inamplifier, two impedance measurement systems are build. Thirdly, contrapose the objectwith low conductivity, the measuring data and law are analyzed, and the relationshipbetween measuring data, impedance and conductivity is discussed. Brain diseases andtraditional diagnostic are introduced, and the study of cerebral hemorrhage simulation iscompleted. Last, a series of experiments with different concentration NaCl solution aremade.The results show that the measurement results of the systems agree well with themagnetic field theory, which indicates that those systems can precisely measure theelectro-conductivity of the conductors. This work has important significance for themagnetic induction impedance measurement technology is applied to the actual clinicalcerebral disease detection in the future. |
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