A preclinical field-free line magnetic particle imaging system for molecular applications

Magnetic Particle Imaging offers unique features for molecular imaging. Its broader use in preclinical research is limited by the accessibility of suitable scanners. To aid in this, a scanner with a mechanically rotated permanent-magnet selection field with a gradient of 2.42 Tm ⁻¹ is presented. It is paired with a modular transmit/receive chain, while feedthrough suppression is provided by a tunable second-order gradiometric receive coil and differential filtering, enabling operation in unshielded environments. The field-generation subsystem requires 413 W, considerably reducing infrastructure demands and permitting long measurements. Within a 40 mm diameter bore, system-matrix reconstruction yields sub-millimeter resolution of ≤ 0.36 mm within a phantom filled with undiluted Perimag plain and a detection limit ≤ 64.4 ng iron in 2D imaging at 1s ⁻¹ rotation. The open software stack and modular hardware facilitate adaptation and scaling. Currently providing 2D images, the platform is poised for 3D through axial translation and algorithmic extensions, offering an accessible, cost-effective route to high-sensitivity preclinical molecular imaging.