A Conductivity Reconstruction Method for Magnetothermoacoustic Imaging Based on the Linear Poisson Equation

Abstract

The invention discloses a magnetic thermoacoustic imaging conductivity reconstruction method based on a linear Poisson's equation. An exciting coil generates an electromagnetic thermoacoustic signal on a conductive object; an ultrasonic transducer receives the electromagnetic thermoacoustic signal; an ultrasonic signal processing and acquiring subsystem acquires and processes the signal; and a control circuit controls the synchronization of a current excitation source, the ultrasonic transducer and the ultrasonic signal processing and acquiring subsystem. The method comprises the following steps: performing circular fault scanning on the electromagnetic thermoacoustic signal by virtue of the ultrasonic transducer, acquiring an electromagnetic ultrasonic signal on the circumference of each fault, and finally combining an image reconstruction algorithm to realize the conductivity image reconstruction. The conductivity image reconstruction method comprises the following steps: firstly defining an objective function meeting a thermoacoustic source, the conductivity, a primary magnetic dislocation spatial component and an electric scalar potential spatial component, giving the initial value of the conductivity, solving the electric scalar potential spatial component according to a current continuity theorem under the condition that the thermoacoustic source distribution is known, substituting the electric scalar potential spatial component and magnetic dislocation spatial component into the objective function, and reconstructing the conductivity distribution.

Description

technical field [0001] The invention relates to a method for reconstructing conductivity images, in particular to a method for reconstructing conductivity in magneto-thermoacoustic imaging based on the linear Poisson equation. Background technique [0002] At present, the sensitivity and spatial resolution of traditional electrical impedance imaging technology are not high, mainly because electrical impedance imaging usually uses electromagnetic waves with low frequency as excitation. Since the wavelength is much larger than the imaging object, the electromagnetic field detection contrast is high, but the resolution is low. Needless to say, a single field has its physical limitations. Therefore, multi-physics imaging technology has received more and more attention, that is, one physical field acts on biological tissue and converts it into another physical field for detection. One physical field provides resolution, and the other provides contrast. , achieving simultaneous i...

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the deficiency that the existing magneto-thermoacoustic imaging method cannot provide the conductivity distribution, and propose a magneto-thermoacoustic imaging conductivity reconstruction method based on the linear Poisson equation optimization iteration. The present invention can accurately reconstruct The conductivity of a conductive object

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