Optical fiber laser-generated-focused-ultrasound transducers for intravascular therapies

Catheter-delivered ultrasound has been widely utilized for intravascular therapies such as thrombolysis, drug delivery, and plaque removal. High amplitude pressure is required for cavitation induced-microstreaming, which is considered main factor for therapeutic efficiency. Precise spatiotemporal control of insonation is important to relieve concerns on ultrasound-induced damaging of surrounding healthy tissue and vessel wall. Recent advances in laser-generated focused ultrasound (LGFU) have demonstrated precisely controlled ultrasound therapies owing to its capability of generating high-pressure (up to 20 MPa), high-frequency (>10 MHz) shock waves at a tight focal spot. Despite of the promising intravascular ultrasound therapies, to date, relatively large (diameter > 12 mm) LGFU transducers composed of carbon-based composite lens have demonstrated their capability only for extracorporeal ultrasound therapies. We hypothesize that the optical fiber LGFU transducer can be used for precise and efficient intravascular therapies taking advantage of high-frequency, high-amplitude shock waves as well as the optically efficient, small aperture optical fibers (Fig. A).