Abstract: In magnetic drug targeting (MDT), a large quantity of magnetic drug particles is absorbed near the magnetic pole, with only a small number of those adsorbed far away from the magnetic pole, where the magnetic field produced by the general electromagnet is attenuated, hindering MDT applications in deep tissue. In this paper, we propose a new noninvasive approach, in which the magnetic field is combined with ultrasound to achieve three-dimensional deep accumulation of magnetic particles. First, the structure design of the experimental equipment for deep aggregation of magnetic particles is presented. Second, the range of ultrasonic amplitudes that can achieve deep aggregation is calculated using the COMSOL simulation software. Finally, an experiment is performed based on simulations and experimental results show that the quantity of magnetic microspheres absorbed in areas far from the magnetic poles is more than those in areas close to the magnetic pole, thereby demonstrating that deep aggregation of magnetic particles was achieved.

Key words: magnetic drug targeting (MDT), magnetic ?eld, ultrasonic wave, cavitation, ?nite element analysis