Title
Signal encoding in magnetic particle imaging: properties of the system function.
Abstract
Magnetic particle imaging (MPI) is a new tomographic imaging technique capable of imaging magnetic tracer material at high temporal and spatial resolution. Image reconstruction requires solving a system of linear equations, which is characterized by a "system function" that establishes the relation between spatial tracer position and frequency response. This paper for the first time reports on the structure and properties of the MPI system function.An analytical derivation of the 1D MPI system function exhibits its explicit dependence on encoding field parameters and tracer properties. Simulations are used to derive properties of the 2D and 3D system function.It is found that for ideal tracer particles in a harmonic excitation field and constant selection field gradient, the 1D system function can be represented by Chebyshev polynomials of the second kind. Exact 1D image reconstruction can thus be performed using the Chebyshev transform. More realistic particle magnetization curves can be treated as a convolution of the derivative of the magnetization curve with the Chebyshev functions. For 2D and 3D imaging, it is found that Lissajous excitation trajectories lead to system functions that are closely related to tensor products of Chebyshev functions.Since to date, the MPI system function has to be measured in time-consuming calibration scans, the additional information derived here can be used to reduce the amount of information to be acquired experimentally and can hence speed up system function acquisition. Furthermore, redundancies found in the system function can be removed to arrive at sparser representations that reduce memory load and allow faster image reconstruction.
Year
DOI
Venue
2009
10.1186/1471-2342-9-4
BMC Medical Imaging
Keywords
Field
DocType
frequency response,linear equations,magnetic resonance imaging,tensor product,spatial resolution,chebyshev polynomial,magnetic particle,algorithms,particle size,image reconstruction,3d imaging
Chebyshev polynomials,Magnetic particle imaging,Artificial intelligence,Iterative reconstruction,Computer vision,Tomographic reconstruction,Frequency response,System of linear equations,Optics,Radiology,Image resolution,Mathematics,Magnetic resonance imaging
Journal
Volume
Issue
ISSN
9
1
1471-2342
Citations 
PageRank 
References 
25
3.57
0
Authors
4
Name
Order
Citations
PageRank
Jürgen Rahmer1415.58
Jürgen Weizenecker2416.94
Bernhard Gleich3549.63
Jörn Borgert4437.74