Novel optically tunable capacitor for RF safe tuning and decoupling of intravascular MR coils
Mueller J, Weiss S, Uelzen T, Pantel G
Hamburg University of Technology
A very compact optically tunable capacitor based on a dedicated metal-oxide-semiconductor interface is proposed, that allows remote optical tuning and decoupling of miniature receive coils for intravascular imaging and catheter tracking. The capacitor is illuminated by laser light guided in an optical fiber and is therefore inherently RF safe, whereas PIN diode based active decoupling would require leads that are prone to RF heating. The capacitance of the device are measured as a function of the incident light power. The device is applied to tune a prototype intravascular receive coil to resonance that can be expanded and therefore changes its inductance.