Methods and apparatuses for generating a steerable pressure field in a shock wave lithotripter
Lithotripter apparatuses and methods are provided for selectively modifying an acoustic pressure field and can include a shock wave source operable to generate a shock wave having a substantially axisymmetric acoustic pressure field, an acoustic focusing member positioned between the shock wave source and a target, and an acoustic barrier positioned between the shock wave source and the acoustic focusing member. The acoustic barrier can be operable to selectively block a portion of the shock wave generated by the shock wave source such that the substantially axisymmetric pressure field is transformed into a modified acoustic pressure field.
1. A lithotripter apparatus for producing a steerable acoustic pressure field, the lithotripter apparatus comprising:
a shock wave source configured to generate a shock wave having a axisymmetric acoustic pressure field;
an acoustic focusing member positioned for receiving the shock wave prior to the shock wave traveling to a target; and
an acoustic barrier positioned between the shock wave source and the acoustic focusing member, the acoustic barrier configured to selectively block a portion of the shock wave generated by the shock wave source such that the axisymmetric pressure field is transformed into a modified acoustic pressure field;
wherein the acoustic barrier comprises:
one or more frames positioned about a perimeter edge of the shock wave source; and
a plurality of inflatable channels constrained by the one or more frames, each of the inflatable channels comprising a first port and a second port for connection to one or more fluid sources, wherein the plurality of inflatable channels are selectively inflatable in a direction extending toward a central axis of the shock wave source.
2. The lithotripter apparatus according to claim 1 , wherein the one or more frames comprise an even number of frames spaced at regular intervals about a central axis of the shock wave source.
3. The lithotripter apparatus according to claim 1 , wherein the inflatable channels are formed in a deformable membrane positioned against the shock wave source.
4. The lithotripter apparatus according to claim 1 , wherein the inflatable channels are formed in a deformable structure that is spaced apart from the shock wave source and the acoustic focusing member.
5. The lithotripter apparatus according to claim 1 , wherein the modified acoustic pressure field comprises a non-axisymmetric pressure field having an elliptical shape.
6. The lithotripter apparatus according to claim 1 , wherein the shock wave source comprises a source selected from the group consisting of an electromagnetic shock wave source, an electrohydraulic shock wave source, and a piezoelectric shock wave source.