Optical Fiber Ultrasound Probe for Radiofrequency Ablation Temperature Monitoring: In-Vitro Results

Abstract

Radiofrequency ablation (RFA) is a clinical technique which inactivates targeted biological tissues by heating to remove tumors or to cure diseases like atrial fibrillation. Temperature is a fundamental parameter for ablation dose control and treatment effect evaluation. This paper presents the design, fabrication and characterization of an all-optical fiber ultrasound temperature measurement probe. The novelty of this probe is to both generate and receive ultrasound optically through fibers. The ultrasound generation was achieved with a 425 μm multi-mode fiber based on photoacoustic (PA) principle and the receiving part applied a 125 μm single mode fiber with a Fabry-Perot (FP) interferometer on its tip. The temperature was measured through detecting the time-of-flight (TOF) of the reflected ultrasound pulses. The probe's feasibility of measuring temperature during ablation had been verified in vitro while excised bovine liver tissue was used as the ultrasound reflector.