A method for locating a variation in one or more electrical impedance properties of an object, the method comprising the steps of: obtaining electrical impedance data for the object at different locations； analysing the obtained electrical impedance data using a transfer function of an assumed electrical model to determine a variation of a plurality of electrical impedance properties for the object with location； and identifying a location identified by a variation of one or more of the plurality of electrical impedance properties. In embodiments the method finds particular use in electrical impedance tomography (EIT) for locating micro bio-channels, acupuncture points and the like.
