INCREASING MAGNETOMOTIVE ULTRASOUND FORCE USING PERMANENT MAGNETS: A FINITE ELEMENT ANALYSIS STUDY

Blood clots are a major contributor of deaths in the United States. Hence, there is need for more precise and accurate diagnostic techniques such as magnetomotive ultrasound (MMUS) which may be able to utilize magnetic nanoparticle (MNP) contrast agents to enhance clot detection. Research has shown that by applying a sinusoidal magnetic force on an MNP-labelled clot, the resonance frequency, and thus the stiffness can be determined. This can aid in making treatment decisions. However, small clots have higher frequencies, which MMUS cannot currently detect. Therefore, there is need to design a setup that optimizes MMUS magnets to generate adequate force at higher frequencies. We created a simulation that matched the existing system and used finite element analysis (FEA) to predict a configuration that enhanced magnet performance. By adding permanent magnets of different sizes and varying the position of the magnets relative to an existing pair of solenoids, the forces imparted were evaluated. FEA predicted that a specific permanent magnet placement could increase the force by a factor of 1.8, and experimental validation showed a similar value of 2.3. These promising results suggest that integrating permanent magnets in our planned MMUS system design holds significant potential for improving performance.