Seraina Murphy with Robert Brown & Fraser Robb (GE Healthcare)

Going Beyond Protons for MR Study

Although high-field MRI coil testing has been a popular research subject for years, the use of carbon-13 in imaging is relatively new.  The potential market for 13C dual-tuned coils has also increased due to the growing popularity of 3T magnets in medical imaging.  However, the number of available dual-tuned coils is limited as much of the 13C research done today is at higher fields (7T and 11.7T).  The goal of this project is the theoretical design and construction of carbon-13 coil prototype—to test a new high-frequency birdcage head coil for use in high-field MRI and for today’s high multiples of receive and transmit channels.  The specific application is for a field strength of 3T and 32-channels.  The aim is to see this new device through to a working model, and to model its performance with new circuit analysis techniques applicable to the higher frequencies, concluding in designing and implementing changes as needed for a successful prototype.  Examples of challenges will involve altering the spacing between the end rings and legs to optimize the performance.  The main physics challenge will be to find effective inductance and capacitance components to use for circuit analysis at high frequency.  Lumped circuit analysis requires modifications when the magnetic field wavelengths inside of a dielectric human tissue become comparable to the coil size.  Understanding the RF physics at high fields is at the cutting edge of MRI coil design today.