Figure 1

One-dimensional signal generation in MPI. The signal formation in acoustically detected magnetic particle imaging bears a lot of similarity to the magnetic case. Assuming that the drive field is zero at a time t0, the total field Htot is given solely by the selection field Hs. As the magnetization M of the particles always points in the same direction as the magnetic field, the magnetization of the particles being left or right of the FFP points in opposite directions. The force always points away from field free point (FFP). Consequently,. when the FFP is moved along the sample by the drive field HD(t1), the magnetization for some of the particles changes from pointing left to pointing right. As the selection field exerts a force on the magnetization, the change in magnetization is accompanied by a change in force. A change in force in a material generates a sound wave, which can be detected with appropriate microphones. Figure 2 - Another sample figure title