IMAGING PHYSICS SEMINAR
University of Massachusetts Boston
Breaking the Rules in Magnetic Particle Imaging
and Ultra-High Field MRI
Magnetic Particle Imaging (MPI) is a new tomographic imaging modality that offers high spatial and temporal resolution. Compared to the other imaging modalities such as MRI/CT/PET, MPI is non-toxic, more sensitive, and fully quantitative technique. To date a few small-bore MPI systems were developed, however, human-size MPI scanner has yet to be built. The major challenge of scaling up of MPI is in high power consumption that is associated with the traditional approach to designing the scanner. In the first part of my talk, I will introduce the basics of MPI, specifically, physics and instrumentation that includes two fundamental types of MPI topologies: field-free-point and field-free-line. Then I will describe my unique approach to designing MPI scanner and also will show how traditional MPI can be blended with AMO physics to incorporate an atomic magnetometer as a very sensitive way of detecting the signal.
In the second part of my presentation, I will talk about propagation wave effects at ultra-high field magnetic resonance imaging (MRI). In conventional MRI near-field RF coils are used as the only excitation method to obtain images of subjects in clinical and research environments. At high-field strength (exceeding 3Tesla), the propagation wave vector of the excitation field can no longer be ignored as the wavelength becomes comparable with the size of the imaging volume, particularly if the medium dielectric constant is large. As ultra-high field MRI scanners are becoming widely available, it is essential to study the associated far-field effects and develop more efficient methods of spin excitation for MRI. I will show how a traveling wave approach can be used to image in a wide range of modern MRI systems spanning from the clinical 3T to the extreme 21T fields.
Host: Michael Martens