Fiber based laser ultrasound transducer for intravascular thrombolysis with detective photoacoustic imaging

Ultrasound-enhanced thrombolysis, or sonothrombolysis, has been actively investigated due to its relatively high efficiency and better safeness compared with traditional thrombolysis methods such as mechanical thrombectomy and pharmaceutical treatment. Most of the ultrasound devices, however, are fabricated with non-biocompatible materials and have limited intravascular application due to size and fabrication complexity. Besides, it is even more challenging to detect blood clot and monitor treatment progress with a traditional ultrasound device. Compared with traditional ultrasound transducer devices, the laser generated ultrasound (LGU) devices generate acoustic waves based on photoacoustic effect and can be made from biocompatible material, with simple fabrication process and controllable size. The same photoacoustic effect can be used for clot detection and treatment monitoring, as hemoglobin is one of the most commonly used endogenous chromophore in photoacoustic imaging. Therefore, in this paper, a fiber-based laser ultrasound transducer was designed and fabricated for the thrombolysis use. Photoacoustic (PA) imaging was also used to monitor the clot condition before and after the treatment.