Arrangement and method for detecting and/or locating a magnetic material in a region of action

摘要

In Magnetic Particle Imaging (MPI) the reconstruction requires the knowledge of a so called system function. This function describes the relation between spatial position and frequency response. For reasonable resolutions and field of views the system function becomes quite large, resulting in large acquisition times for the system function and high memory demand during reconstruction. The present invention proposes to reduce the size of the system function matrix by making use of structural properties of the matrix. Such properties are, for instance, spatial symmetries reducing the number of columns and identical responses at different frequencies reducing the number of rows. In other embodiments the matrix can be transformed to a sparse representation using appropriate base functions.

主权项

1. An arrangement for magnetic particle imaging, the arrangement comprising:
a selector configured to generate a magnetic selection field having a pattern in space indicating strength of the magnetic selection field and to form, in a region of action, a first sub-zone having a lower magnetic field strength and a second sub-zone having a higher magnetic field strength; a drive configured to change the position in space of the first and second sub-zones using a magnetic drive field so that magnetization of magnetic material within the region of action changes locally; a receiver configured to detect signals dependent on the magnetization in the region of action, wherein the magnetization is influenced by the change in the position in space of the first and second sub-zones; a controller configured to:
control the selector, drive, and receiver to measure signals of an object of interest within the region of action,control the selector, drive, and receiver to measure signals of a probe of magnetic material within the region of action forming a subset of a complete system function dataset,wherein said complete system function dataset describes a relationship between spatial position of the probe of magnetic material and a frequency response for said arrangement at all spatial positions within the region of action, andwherein said subset is a reduction and/or truncation of the complete system function dataset exploiting knowledge about a structure of the complete system function dataset; and an image processor configured to reconstruct a magnetic particle spatial distribution of the object of interest within the region of action using the measured signals of the object of interest, the subset of the complete system function dataset, and the knowledge about the structure of the complete system function dataset.