Three-channel receive-only RF coil for vertical-field MR guided focused ultrasound surgery

Focused ultrasound plays an important role in local hyperthermia treatment. Magnetic resonance imaging (MRI) can be used for monitoring temperature during a thermo-coagulation treatment of tumors. The combination of these two technologies offers great advantages for oncology treatment. Currently, only horizontal-field MR guided focused ultrasound systems are available clinically, but the circular magnetic field restricts the operational space during surgery. Vertical-field open MR could provide wider access to patients during the ultrasound surgery and thus increase the potential clinical applications. A key component to facilitate such a system is the radio frequency (RF) coils. Common RF coils of vertical-field MR are not adaptive to combined system because there is no unhindered path for ultrasound beams to pass. A special three-channel receive-only RF coil with a 27 cm aperture to pass ultrasound beams was designed and reported first time. Phantom scan, body imaging and temperature measurements were all taken with the specially designed prototype coil. The results show that the designed coil was functionally adaptive to the vertical-field MR guided focused ultrasound system.