In-vivo imaging of tumor mouse model with a single-sided magnetic particle imaging scanner

Magnetic Particle Imaging (MPI) is an emerging,radiation-free molecular imaging modality that detects superparamagnetic iron oxide nanoparticle (SPION) tracers. Unlike traditional closed-bore systems, the single-sided MPI scanner developed at Oakland University houses all hardware on one side, providing open access to the scanning area and greater flexibility for potential clinical applications.This study evaluates the scanner’s sensitivity and spatial resolution for in vivo tumor detection. In our validation study we utilized syngeneic 4T1 breast cancer model in BALB/c mice according to the approved IACUC protocol. In this study, two mice of different tumor volumes received intratumoral injections of either Synomag-D (70nm) or MagTrace (60nm) SPIONs. Imaging was performed after variable delay times within an 8x8 cm² field of view (FOV) with the mice in a prone position and tumor within the FOV. To provide anatomical context, MPI images were co-registered with photographs using a custom-developed hardware and interface. MPI images confirmed the presence of SPIONs in the tumors in both mice. Images of horizontal slices of tumors were also taken at different heights and variations of the tracer uptake in different slices were observed. In addition, signal decay was observed in images acquired after the extended delay times. In this pilot phase, we demonstrated the MPI scanner’s capability for in vivo detection of tumors.The next goal of the study is to evaluate the scanner’s capability to detect tumors followings ystemic intravenous SPION injection, which is critical for diagnostic imaging.The ultimate aim is to optimize the single-sided scanner for future translation into human breast cancer diagnostics.