Apparatus and method for determining at least one electromagnetic quantity

Abstract

The present invention relates to an apparatus (100) for determining at least one electromagnetic quantity characterizing an electromagnetic property of an object, in particular a human body, wherein said object contains magnetic particles. The apparatus (100) applying the known principle of Magnetic Particle Imaging (MPI) comprises selection means for generating a magnetic selection field (50) having the known field pattern showing a field free point (FFP), drive means for changing the position in space of the FFP by means of a magnetic drive field, receiving means for acquiring detection signals depending on the magnetization of the magnetic particles within a field of view (28) and a reconstruction unit (152) for reconstructing a particle distribution quantity depending on the detection signals. The apparatus (100) further comprises a control unit (150) for controlling the receiving means for acquiring a first set of detection signals corresponding to a first drive field frequency and a second set of detection signals corresponding to a second drive field frequency, with both drive field frequencies differing from each other. The control unit (15) further controls the reconstruction unit (152) for reconstructing a first particle distribution quantity depending on the first set of detection signals and a second particle distribution quantity depending on the second set of detection signals. The apparatus (100) further comprises a determination unit (160) for determining the electromagnetic quantity depending on the first and second particle distribution quantity. The present invention further relates to a corresponding method as well as to a computer program.

Description

technical field [0001] The invention relates to a device and a corresponding method for determining at least one electromagnetic quantity. Furthermore, the invention relates to a computer program for implementing said method on a computer and for controlling such a device. Background technique [0002] In medical imaging, the properties of biological tissue are used to generate image contrast. For example, the electrical conductivity is different for different types of tissue. Therefore, conductivity quantities that characterize the distribution of conductivity throughout at least a portion of the human body are important for distinguishing between different tissues of the human body. For example, the conductivity quantity can be used to distinguish tumor from healthy tissue or necrotic tissue from viable tissue after myocardial infarction. The conductivity quantities can also be used to support the characterization of brain tissue associated with stroke or cerebral hemor...

AI Technical Summary

Problems solved by technology

Although the amount of time required to prepare before measurements can be made is relatively small, the use of this method is limited because of the following disadvantages: First, the frequency of the exciting electromagnetic field is fixed to the so-called Larmor frequency of the MR system involved. frequency, which is significantly higher than that required for most correspondence studies

Second, because the exciting electromagnetic field cannot be rotated for MR systems, conductivity anisotropy can only be studied for a very small number of partially "rotatable" body parts, like hands, feet, and heads

Third, the MR scanner is a rather expensive imaging modality, especially since for EPT it is "only" used to generate and measure magnetic fields

So far MPI devices and methods are not suitable for determining electromagnetic quantities

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