Forward-looking ultrasound imager using convex-shaped 1-3composite transducer for intravascular treatment

An intravascular forward-looking ultrasound probe (FLUP) of 3 mm in diameter has been developed. We used the FLUP as acoustic sources and receivers to make an ultrasound forward-looking image, but many artifacts were observed because of strong directivity of the FLUP. To confirm the affection of directivity in ultrasound forward-looking images, laser induced breakdown (LIB) was used as a low directional transmitter and a FLUP was used as a receiver, a fine image was successfully obtained because the LIB can provide an almost, completely spherical ultrasound pulse wave. For decreasing the directivity of FLUP, a convex-shaped 1-3composite PZT transducer (0.7 mm in diameter and 0.75 mm curvature radius) was fabricated, and low directivity feature was confirmed. A probe which has eight separated 1-3composite convex-shaped transducers were fabricated. The probe is 5 mm in diameter and a working channel is 0.5 mm in diameter. Acoustic pressure was measured using a hydrophone which was located 10 mm in front of the FLUP. The emitting acoustic pressure of 40 Pa was realized with the fabricated probe. When the probe was used as acoustic sources and receivers, echo signal of an aluminum plate was observed.