Conceptual and simulative study of the transverse electromagnetic (TEM) RF coil as an RF hyperthermia applicator at 9.4 Tesla

The objective of this publication is to provide a conceptual and simulative study of a multi-channel hybrid coil system used primarily in magnetic resonance (MR) systems for imaging as a heat inducing system for RF hyperthermia applications. A 16-channels transverse electromagnetic (TEM) coil has been designed for dual purposes as a heat inducing device and as a transceiver for magnetic resonance imaging at 400 MHz (equivalent to the protons Larmor frequency at 9.4 Tesla). Full wave and circuit-wave co-simulations have been carried out. The point specific absorption rate (SAR) pattern is computed. The 3dB width of the formed `hotspot' is also evaluated and analyzed. Good matching (-28 dB) has been achieved at 400 MHz. The coupling between adjacent elements was -10.81 dB. The point SAR (with 1 W as accepted power) shows a clear sharp hotspot when the coils are used for heating. The 3dB width of the RF induced hotspot was 38 mm. The TEM RF coil used in high field MRI system, can be used as an RF hyperthermia applicator for simultaneous heating and imaging. The performance of the system shows a clear advantage compared to existing commercial system. No water bolus is required.