A concept for an mpi scanner with halbach arrays

One of the major challenges of MPI is the upscaling of scanners. Typically, the magnetic fields are generated electromagnetically with immense power consumption, which becomes a severe issue for larger setups. However, electromagnets provide high flexibility in terms of adjusting the gradient strength of the selection field and providing quickly alternating drive fields. The scanner concept proposed here reduces the power consumption drastically, because both the selection field and the drive field are generated by rotating permanent magnets. In addition, it maintains the flexibility to adjust the gradient strength for different imaging sequences. The selection field consists of two concentric Halbach quadrupoles. Mutual rotation of the nested quadrupoles enables the variation of the gradient strength. The drive field is generated by two reversely rotating Halbach dipoles driving the field free point on a radial trajectory. To show the feasibility of the setup an exemplary image simulation with an additional excitation field is performed and the resulting reconstruction is discussed.