A method comprising providing a reflective region at a far side of tissue of a subject is provided. The method includes assessing whether the reflective region is in a desired location, by means of acoustic sensing and in response to assessing that the reflective region is in the desired location, activating an ultrasound transducer to ablate the tissue by applying ultrasound energy to a near side of the tissue, such that at least a portion of the transmitted energy is reflected by the reflective region onto the tissue of the subject. Other embodiments are also described.
