Experimental 3D X-space magnetic particle imaging using projection reconstruction

Abstract

Tomographic imaging using a shifted and rotated field free line (FFL) with filtered backprojection image reconstruction can approach an order of magnitude SNR improvement over a field free point (FFP) given equal scan time. In this paper, we demonstrate a projection reconstruction x-space imager. The imager consists of a 2.4 T/m permanent magnet FFL gradient, a Helmholtz pair of off-the-shelf electromagnets, a solenoidal transmit coil and a gradiometer receive coil. A motor driven rotary table rotates the sample and the system acquires multiple projection images at evenly spaced angles between zero degrees and 180 degrees. Filtered back-projection is used to reconstruct a three-dimensional tomographic image stack. Sample rotation, which is sometimes employed in commercial mouse CT scanners, has been used to test this method. Later systems may rotate the gradient similar to a human-sized CT gantry or may generate an electronically rotated FFL gradient. In previous work, we have shown an MPI capable FFL scanner. Here, we show 3D experimental results of our PR-MPI scanner using acrylic USPIO imaging phantoms and post-mortem mice.