On the Optimization of Sinogram-based Calibration

Sinogram-based calibration in Magnetic Particle Imaging (MPI) using a 3D field free line (FFL) trajectory offers high-quality system matrices. This approach involves repeating the imaging trajectory at multiple trajectory offsets in sinogram domain. However, transitions between these repetitions can introduce unwanted spectral components (USCs), potentially overloading transmit electronics. This work investigates and compares three strategies, namely stop & go, circularly-shifted, and all-ramp, for their impact on spectral purity. Simulations demonstrate that the circularly-shifted design maintains trajectory stability and significantly suppresses USCs, while the all-ramp approach achieves the shortest calibration time and minimal USCs at the cost of a slight infidelity to the actual trajectory. These results highlight trade-offs between spectral purity, trajectory accuracy, and efficiency, providing practical guidelines for optimizing sinogram-based calibration.