Beyond Standard MRI Radio Frequency Detectors and Arrays for High Field and High Density Applications

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This research program aims to advance the technology of radio frequency (RF) detector "coils" and systems for magnetic resonance imaging (MRI). During the past five years of NSERC funding I have established a new lab at the University of Alberta and we have discovered unique technical solutions that will improve the quality and acquisition speed of MR images. We will begin by verifying these approaches experimentally by building versions of RF coils with and without the new technologies and comparing the results. Another way to achieve improvements in MRI speed and image quality is to make the large magnets on which MRI is based much stronger. However, as the magnetic field increases it becomes more difficult to produce images without bright and dark areas that make them harder to interpret by radiologists. At the strongest magnetic fields (7 tesla or more) imaging large areas and organs of the body such as the gut becomes intractable. At the University of Alberta we have an intermediate strength magnet (4.7 tesla), which is stronger than the strongest ones used routinely in hospitals (3 tesla) and will be upgraded with RF transmitter technology (funded by CFI) that allows the bright and dark areas of the images to be adjusted for the best uniformity. This has never been done at 4.7 tesla and it allows us to explore body imaging at this intermediate magnetic field strength. We will develop RF "antennas" optimized for this field strength by using simulations and measurements on phantoms that mimic the body. This research program also aims to design RF coils that are optimized for the PET-MRI system (also funded by CFI) that will be installed in Edmonton's cancer hospital. Positron emission tomography (PET) is used to identify tumors after the patient is injected with a radioactive tracer. However, the RF coils used for the MRI part of the machine interfere with the readings taken by the PET detectors. We aim to eliminate this interference by making the RF coils as "transparent" as possible to the PET by using new, thinner materials.