A new laser-ultrasound transducer for medical applications.

A new type of probe is presented, which combines an ultrasound receiver constructed from piezoelectric polymer materials with a coaxial optical fibre for laser-induced ultrasound. The initial application of this probe, which may be further miniaturized, is in intra-arterial imaging and therapy. Overall diameters of the prototype probes presently range from 2.5 mm to 10.0 mm. Pulsed laser beams are introduced through the optical fibre to form a photoacoustic source within the material under investigation. Ultrasonic waves are induced in the material due to the photo-acoustic effect and received on return by a forward-looking piezoelectric polymer transducer. In principle, other high-power laser beams can also be introduced through the same optical fibre for therapeutic use. Initial development and characterization of this combined probe is reported in this paper, together with some results.