A FIELD CANCELATION SIGNAL EXTRACTION METHOD FOR MAGNETIC PARTICLE IMAGING

Area of Science:

• Medical Imaging
• Biophysics
• Electrical Engineering

Background:

• Magnetic Particle Imaging (MPI) simultaneously detects signals and uses excitation fields, causing strong coupling between the drive field (DF) and receive chain.
• High DF signal levels necessitate signal suppression to maintain a feasible dynamic range for analog-to-digital conversion in MPI systems.
• Existing methods like band-stop filters remove DF signals but also eliminate crucial fundamental harmonic components of magnetic nanoparticle (MNP) signals, vital for concentration reconstruction.

Purpose of the Study:

• To propose and evaluate a novel field-cancelation (FC) concept for a receive coil (RC) in MPI.
• To design an FC-RC that minimizes inductive coupling with the drive field (DF) while remaining sensitive to magnetic nanoparticle (MNP) signals.
• To validate the effectiveness of the FC-RC in reducing mutual inductive coupling through simulations and experimental measurements.

Main Methods:

• A field-cancelation (FC) receive coil (RC) was designed, comprising a primary coil sensitive to MNP signals and a cancelation coil to minimize DF coupling.
• Thin-wire approximation was used to calculate sensitivity plots and mutual coupling coefficients.
• A prototype FC-RC was manufactured and tested in a mouse MPI scanner to measure the reduction in mutual inductive coupling.

Main Results:

• Simulations predicted a mutual inductive coupling reduction of 70 dB (ds).
• Experimental measurements on the prototype FC-RC demonstrated a reduction of 55 dB (dms).
• The discrepancy between simulated and measured results highlights the feasibility of the FC concept and indicates areas for further investigation.

Conclusions:

• The proposed field-cancelation (FC) receive coil (RC) concept is a feasible approach to mitigate drive field (DF) interference in Magnetic Particle Imaging (MPI).
• The FC-RC design successfully reduced inductive coupling, preserving the fundamental harmonic components of magnetic nanoparticle (MNP) signals.
• Further research is warranted to optimize the FC-RC design and improve performance for practical MPI applications.