Performance improvement of magnetoacoustic harmonic imaging for magnetic nanoparticles based on the electromagnetic excitation with a conical core

Abstract

Magnetic nanoparticles (MNPs) show prosperous application potentials in medical imaging due to the unique magneto- and bio-characteristics. In order to improve the performance of magnetoacoustic harmonic (MAH) imaging for MNPs, a conical iron core wound by an electromagnetic coil is designed to generate strengthened magnetoacoustic harmonic responses (MAHR) in a converging effective magnetic volume (EMV). Based on the theoretical simulations and the experimental measurements, it is proved that the MAHR shows a linear relationship with the MNP concentration, exhibiting an improved measurement resolution for the core with a smaller cone angle. The performance improvement is also demonstrated by the 1-D distributions of the MAHR, and the dependences of the penetration depth and the MNP concentration using a laser vibrometer. In addition, the measurement resolution of the MAHR can be further optimized by implementing a toroidal permalloy around the cone tip. The favorable results provide an improved performance of the MAH imaging with the advantages of simple structure, precise positioning, stable measurement, anti-interference and high accuracy, suggesting application potentials in biomedical engineering.