Therapy apparatus for treating tissue by the emission of remote crossed focused ultrasound waves

A therapy apparatus for treating tissue by the emission of focused ultrasound waves, comprising:

• a therapy probe having a transducer comprising a plurality of ultrasound emitters defining an emission face of focused ultrasound waves having an axis of symmetry corresponding to the acoustic axis, or a plane of symmetry corresponding to the acoustic plane, these ultrasound emitters being activated by signals delivered by a signal generator forming part of a control circuit, to define a creation surface of a pressure field of focused ultrasound waves;
• wherein the creation surface is divided into N sectors, where N is from 2 to 32, to focus the ultrasound waves on focal zones being defined in focal planes, the sectors of this creation surface having in a profile plane segments of concave curve of finite length, asymmetrical relative to the plane of symmetry, or the axis of symmetry;
• wherein the centres of curvature are asymmetrical relative to the plane, or to the axis of symmetry, to the extent where the centres of curvature are situated at different distances from the plane of symmetry, or from at least one of the axis of symmetry, and at different depths taken according to the axis of symmetry;
• wherein each segment of concave curve has its own axis passing through a centre of curvature of said segment of concave curve and the middle of said segment of concave curve;
• wherein the individual axes intersect between the focal zones and the creation surface, or beyond the focal zones, such that the beams originating from the sectors intersect to create a focal coverage zone which is off-axis relative to the plane of symmetry, or to the axis of symmetry, and situated at a distance from the focal planes, between the focal zones and the creation surface, or beyond the focal zones;
• wherein the sectors of this creation surface are engendered either by rotation of 2π/N of the segments of concave curve around the axis of symmetry, or by translation of the segments of curve according to a direction perpendicular to the profile plane containing said segments of curve such that the sectors can create energy deposit zones with profiles corresponding to the focal coverage zones;
• wherein the segments of curve of the creation surface extend in the profile plane on either side of the axis of symmetry, or of the plane of symmetry, by being separate to allow positioning of the focal coverage zone at a distance from the creation surface;
• wherein each one of the plurality of ultrasound emitters is connected to its own signal generator;
• wherein, in an exposure phase, the ultrasound emitters forming part of a sector, and of the symmetrically opposite sector relative to the plane of symmetry, are activated by signals delivered by the signal generator forming part of the control circuit to create the corresponding energy deposit zone to one side of the plane of symmetry;
• and
• wherein, in a subsequent exposure phase, the ultrasound emitters forming part of a sector, and of the symmetrically opposite sector relative to the plane of symmetry, are activated by signals delivered by the signal generator forming part of the control circuit to create the corresponding energy deposit zone of the side opposite the side in which the energy deposit zone of the preceding exposure phase is created.