Image Reconstruction Based on Newton-Raphson Method for Magnetic Particle Imaging

Magnetic particle imaging (MPI) is an emerging imaging modality that measures the non-linear magnetization response of superparamagnetic iron oxide nanoparticles (SPI-ONs) to visualize the spatial distribution of the SPIONs. The performance of the image reconstruction methods significantly influences the quality of the MPI images. The selection of a proper image reconstruction method is of great importance for MPI. In this work, the Newton-Raphson method was introduced to reconstruct MPI images. Numerical simulations were carried out to evaluate the performance of the image reconstruction methods, which is compared with two commonly-used reconstruction methods in MPI, including the algebraic reconstruction technique (ART) and the alternating direction method of multipliers (ADMM). In the simulation, a phantom with radial distribution is designed to evaluate the spatial resolution of the methods in different directions. The modulation transfer function (MTF) and the structural similarity index measure (SSIM) between the designed original phantom and reconstructed images are used as evaluation criteria to evaluate the image quality and resolution of the reconstructed methods. The results show that the Newton-Raphson method is an efficient image reconstruction method that can be applied to MPI, and the reconstructed images using the Newton-Raphson method have relatively higher structural similarity, fewer artifacts, and higher resolution in both x and z directions.