A Novel Hand-Held Multi-Color Magnetic Particle Imaging Device Based on Rapid Frequency Conversion

Objective: Multi-color Magnetic Particle Imaging (MPI) technology offers high sensitivity and non-invasive imaging capabilities. It can simultaneously image multiple superparamagnetic iron oxide nanoparticles (SPIOs), facilitating more precise detection of multiple molecular markers in vivo. However, the fixed drive frequency of existing hand-held MPI devices makes it difficult to fully match the nonlinear magnetic response of different SPIOs, affecting the effect of multi-color imaging. Methods: We designed a novel hand-held rapid frequency conversion based multi-color MPI (RFC-MPI) device. This device adjusts the drive frequency based on magnetic response at different frequencies, effectively expanding the system matrix information and thereby improving spatial resolution and multi-color imaging capabilities simultaneously. Results: The device achieved a spatial resolution of 27 mm and an imaging speed of 1 frame/s. The scanning depth is 8 mm. It was used to scan a 22 cm x 22 cm area of a human-shaped phantom, verifying its potential for scanning humans. The ability of the device to quantify SPIOs was validated using mice breast tumors. The quantitative accuracy was determined to be 96.58%. Conclusion: Due to its innovative structural design and rapid frequency conversion method, the RFC-MPI device exhibits excellent in vivo imaging performance. Both simulation and phantom experiments have verified the effectiveness of the proposed method. Significance: The hand-held RFC-MPI device can effectively improve the spatial resolution and quantitative accuracy of multi-color MPI, laying the foundation for future clinical applications.