Apparatus comprising a reflection-facilitation element, which is disposed in the pericardial cavity of a subject and on a first side of a tissue of the subject. The reflection-facilitation element comprises an inflatable member, having a first side and a second side, and configured to be inflated while disposed in the pericardial cavity, and a plurality of electrodes, comprising at least a first electrode and a second electrode, the first electrode being disposed on the first side of the inflatable member. The apparatus further comprises an ultrasound transducer placed on a second side of the tissue of the subject, and configured to apply ultrasound energy to the tissue of the subject such that at least a portion of the energy reaches the inflatable member. The inflatable member reflects at least a portion of the ultrasound energy that reaches the inflatable member.

An apparatus includes a balloon adapted to be placed adjacent a calcified region of a body. The balloon is inflatable with a liquid. The apparatus further includes a shock wave generator within the balloon that produces shock waves that propagate through the liquid for impinging upon the calcified region adjacent the balloon. The shock wave generator includes a plurality of shock wave sources distributed within the balloon.

An apparatus includes a balloon adapted to be placed adjacent a calcified region of a body. The balloon is inflatable with a liquid. The apparatus further includes a shock wave generator within the balloon that produces shock waves that propagate through the liquid for impinging upon the calcified region adjacent the balloon. The shock wave generator includes a plurality of shock wave sources distributed within the balloon.

A system may include an ultrasound transducer. A system may include a catheter for insertion into a body lumen of a patient, the catheter including a distal end. A system may include a reflector connected to the distal end of the catheter, the reflector formed from a material having an acoustic impedance mismatch with an adjacent material. Optical energy may be delivered through the catheter.

An apparatus includes a balloon adapted to be placed adjacent a calcified region of a body. The balloon is inflatable with a liquid. The apparatus further includes a shock wave generator within the balloon that produces shock waves that propagate through the liquid for impinging upon the calcified region adjacent the balloon. The shock wave generator includes a plurality of shock wave sources distributed within the balloon.