Yong Wu1, Zhen Yao1, Gareth Kafka1, David Farrell1, Mark Griswold2, Robert Brown1
1Department of Physics, Case Western Reserve University, Cleveland, OH, United States; 2Department of Radiology, Case Western Reserve University, Cleveland, OH, United States
Magnetic particle imaging (MPI) is a new tomographic technique that allows fast, inexpensive imaging of MRI contrast ferrofluid agents with submillimeter resolution. Selection fields combined with oscillating driving fields can move unsaturated field-free-points so as to cover the field of view. In previous studies, the average magnetization is assumed to respond instantaneously to changes in the applied field. Realistically, however, a finite relaxation time slows the magnetic response. The present simulation demonstrates that, for contrast agents of interest, the choice of an optimal particle size is strongly dependent on this effect. A trade-off thus exists between sensitivity and resolution.