Adjustable Hardware Lens for Traveling Wave Magnetic Particle Imaging

Magnetic particle imaging (MPI) is a promising tomographic technique for the fast and sensitive visualization of superparamagnetic iron-oxide nanoparticles (SPIONs). Different types of MPI scanners have been presented in the past providing 2-D as well as 3-D data with different sizes of the field of view (FOV). With increasing FOVs, often the spatial resolution decreases. Traveling wave MPI (TWMPI) scanners provide the possibility to visualize the entire available FOV within the scanner at once with a good spatial resolution and a high temporal resolution. However, a more selective imaging process, such as scanning specific areas within the sample collecting more information, is of high interest. This can be performed by adjusting the sequences for signal acquisition, e.g., by modulation of the amplitude, to actively suppress signal generation in specific areas. Unfortunately, this method requires the adaptation of the hardware. In this article, a novel approach for imaging specific areas within the FOV of a TWMPI scanner is presented without specific hardware modifications. Furthermore, this technique offers the possibility to increase the resolution by up to 40%, which reveals more details in this area, similar to a magnification effect.