The Design Of Exciting Coil For Magnetic Induction Tomography System Based On The Technique Of 3D Focused Magnetic Field

Magnetic induction tomography is a technique to image the electrical conductivity distribution within the biological tissue. This technique has been variously named mutual inductance tomography (also MIT) or electromagnetic tomography (EMT). The technique has attracted interest for biomedical application due to the non-contacting measurements, which may provide advantages over electrode based impedance tomography in certain applications. It is a new imaging modality being developed for the process industry and for medical imaging. Although some research groups have done more and more work on this technique, it is far from perfect up to the present. A number of experimental systems exist, but so far no magnetic induction tomography system has reached routine use either industrially or medically.There is much great difficulty about magnetic induction tomography that is not solved now. A major problem to be overcome in developing a practical biomedical magnetic induction tomography system is to accurately measure the small perturbation of the received signal due to the induced eddy currents given the relatively low conductivity of biological tissue. This paper describes a new idea that was presented by our research groups on how to accurately measure the small perturbation. The idea is that magnetic induction tomography system based on the technique of 3D focused magnetic field can accurately measure the small perturbation.The inductance of the rectangular plan spiral coil is calculated in this paper.The calculated results are in agreement with the results calculated by approximate formula. It is found that the magnetic fields generated by the rectangular plan spiral coil can focus in a small area. The changes of inductance and resistance by the conductivity of biological tissue are calculated also. Furthermore, the forward problem and inverse problem of magnetic induction tomography were analyzed simply in this paper.The magnetic field generated by several kinds of coils was calculated. The changes of inductance and resistance by the conductivity of biological tissue are calculated also. It is found that the magnetic fields generated by the conical spiral coil can focus in a very small area and the conical spiral coil is best choice of the exciting coil for magnetic induction tomography of biological tissue. The magnetic fields generated by the coronary spiral coil can also focus in a very small area. Further more, it will be advantageous to measure the conductivity of the brain if the coronary spiral coil is used as the exciting coil for magnetic induction tomography .