Systems and methods for focussing an acoustic energy beam transmitted through non-uniform tissue medium

Abstract

Systems and methods for focussing an ultrasound energy beam transmitted from an array of transducer elements located outside the body through a non-uniform tissue medium, such as a skull, to a location (e.g., a tumor) located inside the body by monitoring a signal representing reflected portions of the beam at a desired focal point or zone through a portion of the medium that does not significantly distort the reflected signal. In one embodiment, a focussed ultrasound system includes a plurality of transmitting transducer elements configured to deliver respective energy waves from locations outside the skull to a focal zone within the skull, the energy waves collectively comprising an energy beam. The system further includes an ultrasound detector having a fixed position relative to the transmitting elements, the detector configured to receive a signal comprising a reflected portion of the beam along a line-of-sight axis through a portion of the skull. A controller is coupled to the transmitter and detector, the controller configured to calculate the intensity of the reflected portion of the beam along the axis based on the timing of the received signal and then adjust the transmission of one or more of the transmitting elements based on the calculated intensity of the reflected portion of the beam along the axis.