Improved Sensitivity of a Single-Sided Magnetic Particle Imaging Scanner

Magnetic Particle Imagining (MPI) is the new frontier of medical imaging, capable of imaging the distribution of superparamagnetic nanoparticles (SPIOs) in an expeditious and sensitive manner. For instance, the accumulation of SPIOs in tumor tissue, serving as tumor markers, presents the MPI device as a practical means of imaging for in vivo cancer imaging. The single-sided design is beneficial for this application allowing imaging of larger subjects. In our design of a scanner we utilize a field-free line (FFL) geometry of the magnetic field zero, which has a potential advantage of an increased sensitivity over the traditional approach with field-free point (FFP). Our prototype device uses a single primary coil to generate a magnetic excitation field. The SPIOs response to the excitation is detected by a planar receive coil on the surface of the device. Due to a single-sided geometry, differentiating a small signal on a strong excitation background becomes a challenging task and further impinges the potential sensitivity gain, thus a new planar gradiometer coil configuration was developed. Results from the numerical simulations and experimental data imply the improved sensitivity of the device over the single coil design.