Abstract: A laser ultrasound probe, suitable for intravascular use, of the kind having an ultrasonic transducer element comprising an ultrasound receiving surface of piezoelectric polymeric material and an optical fiber with one end directed forwardly from that surface and arranged to receive laser radiation for transmission through the optical fiber and emission from the said one end thereof, wherein the optical fiber is coupled with laser source means adapted to provide alternatively a relatively low average power laser beam, which, when modulated or pulsed and emitted from the one end of the optical fiber and incident on a target, will generate ultrasound at an intensity suitable to be received by the transducer element and converted thereby into electrical monitoring signals, and a relatively high average power laser beam suitable, when incident on the said target, to produce ablation thereof, the transducer element being sufficiently robust to withstand the ultrasound which is then also generated.