The Preliminary Research On The Technology Of Magnetic Induction Impedance Tomography

Magnetic Induction Impedance Tomography ( MIT ), a kind of imaging technology for measuring the distribution of biological tissue's electrical impedance or conductivity by applying the theory of electrical magnetic field detecting. As a new method of contactless electrical impedance tomography, MIT has some great prospective application in distinguishing different types of encephalic pathological changes. In this paper, we fulfilled the preliminary MIT research that is the basis of the imaging monitor system for the cerebral wound emergency.When detecting brain's impedance in MIT, the object is the brain tissue with minor conductivity, which can induce some weak eddy current that is easy to be interfered by outside magnetic field. For this reason, we designed and realized a single-channel measuring system based on a physical phantom to detect the phase changes of eddy current induced from the object with conductivity changing. The main content is as follows:1. designed and fulfilled the exciting source, and its output specifications loaded with a coil met the design requirements.2. designed and fulfilled the measuring circuit, sensitivity experiment of which met the design requirements.3. developed the coils that were properly used under the Exciting -Measuring mode of MIT. And we presented the principle and method how to select coils.4. designed and made the single-channel circumvolving platform with screen and applied stepping motors to control the coils rotating certain angle precisely. Then we automatically obtained independent measuring numbers.5. realized the back-projection algorithm of MIT. We put forward the weighed method in a straight line along the main magnetic field. The algorithm was proved to be applicable by the images of modeled object with different conductivity in various position.6. the preliminary and ideal imaging results were given by utilizing NaCl brine as an object in this paper, which approximately had the same conductivity with the normal human brain tissue.And we made the errors of results analyzed and gave some possible advice on improving them.