Position sensing of magnetite gel using MI sensor for brain tumor detection

A brain tumor position sensing method using an MI (magneto impedance) micro magnetic sensor in combination with fine magnetic particles (FMP for short) is proposed. Sensing of the magnetic field generated from FMP accumulated in brain tumor tissue would be an effective way to accurately detect the tumor position in a surgical operation. The spatial distributions of stray fields in gel samples, in which FMP were dispersed, were measured using an MI gradient-field sensor. The position of samples having FMP concentration of more than 0.1 g/l was clearly detected due to the high sensitivity (2/spl times/10/sup -5/ Oe for a dc field) of the sensor. The spatial distributions were analyzed by a model of aligned dipole moments. The calculation results using the model were in good agreement with experimental results. Position sensing of the tumor tissue of a rat was also carried out It was concluded that the proposed method would be useful for not only position sensing of the brain tumor but also 3D imaging of the tumor shape.