Ultrasonic applicator for medical applications

• US 6,217,530 B1
• Filed: 05/14/1999
• Issued: 04/17/2001
• Est. Priority Date: 05/14/1999
• Status: Active Grant

• Current Assignee: Washington University In St Louis
• Original Assignee: University of Washington
• Inventors: Martin, Roy W., Proctor, Andrew H., Brentnall, Mark D.
• Primary Examiner(s): Lateef, Marvin M.
• Assistant Examiner(s): SHAW, SHAWNA JEANNINE
• Application Number:
  US09/312,745
• Time in Patent Office: 704 Days
• Field of Search: 601/2, 601/3, 600/439, 600/459, 310/311, 310/335, 310/348, 310/349, 310/367, 310/371
• US Class Current: 601/2
• CPC Class Codes: A61B 17/22004 using mechanical vibrations, e.g. ultrasonic shock waves A61B17/225 takes precedence
• CPC Class Codes: A61B 17/2251 characterised by coupling elements between the apparatus, e.g. shock wave apparatus or locating means, and the patient, e.g. details of bags, pressure control of bag on patient
• CPC Class Codes: A61B 17/3203 Fluid jet cutting instruments
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• CPC Class Codes: A61B 2017/320069 for ablating tissue
• CPC Class Codes: A61B 2090/0813 Accessories designed for easy sterilising, i.e. re-usable
• CPC Class Codes: A61B 8/4272 involving the acoustic interface between the transducer and the tissue
• CPC Class Codes: A61B 8/4444 related to the probe
• CPC Class Codes: A61N 7/00 Ultrasound therapy lithotripsy A61B17/22, A61B17/225; massage using supersonic vibration A61H23/00 ; using ultrasound for introducing media into the body A61M37/0092
• CPC Class Codes: B06B 3/00 Methods or apparatus specially adapted for transmitting mechanical vibrations of infrasonic, sonic, or ultrasonic frequency

Abstract

A medical instrument uses solid tapered cones mounted to a preferably concave, spherically curved, piezoelectric ultrasound transducer which focuses and concentrates the ultrasound energy to a narrow tip so very high levels of ultrasound can be delivered to the tissue adjacent to the tip. Ultrasound matching layers or variable curvature geometries are employed at the tip aid in transferring the energy from the tip to the tissue.

Claims

1. A high intensity focused ultrasound medical instrument comprising:

a handle;

mounted to the handle, a housing including a cavity;

a transducer having a substantially concave geometry for providing a focused ultrasonic beam from a transducer concave frontside thereof, wherein the transducer is mounted in the housing such that a transducer backside thereof is open to the cavity; and

an ultrasound applicator, having an applicator backside having a convex geometry substantially identical to the concave geometry of the transducer, the applicator is nested with the transducer with the transducer concave frontside substantially adjacent the applicator backside, the applicator being a solid material having a truncated tip such that the tip forms a lens for refocusing the beam, wherein the handle is adapted for providing a conduit for coupling power and a cooling medium to the cavity.

2. The instrument as set forth in claim 1, comprising:

the instrument is autoclavable.

3. The instrument as set forth in claim 1, comprising:

the handle has a geometric construction for facilitating reaching selective target regions within living tissue during medical procedures.

4. The instrument as set forth in claim 1, comprising:

the transducer generates sonic waves having frequencies in a range of approximately 0.5 MHZ to 50 MHZ.

5. The instrument as set forth in claim 1, comprising:

the applicator is of a conical geometric configuration, and

the truncated tip is a concave surface subjacent the apex of a cone wherein the concave surface has a radius of curvature substantially equal to the radius of curvature of the concave geometry of the transducer.

6. The instrument as set forth in claim 1, comprising:

the truncated tip is a concave surface within the solid material of the cone wherein the concave surface has a radius of curvature substantially equal to the radius of curvature of the concave geometry of the transducer, the concave surface being recessed into the cone a predetermined distance such that the distance is approximately equal to a focal length of the beam.

7. The instrument as set forth in claim 1, comprising:

the truncated tip is a concave surface subjacent the apex of the cone wherein the concave surface has a predetermined radius of curvature selected to generate a focal region of the beam a predetermined distance from the tip based upon the focal length of the transducer.

8. The instrument as set forth in claim 1, comprising:

the truncated tip is a convex surface subjacent the apex of the cone whereby beam spreading is initiated immediately adjacent the tip.

9. The instrument as set forth in claim 1, comprising:

the applicator having a central passageway, extending from the applicator backside through to the truncated tip, for conducting secondary energy means for providing medical therapy therethrough.

10. The instrument as set forth in claim 1, further comprising:

means for providing a secondary energy to the tip.

11. The instrument as set forth in claim 10, comprising:

the secondary energy is bi-directional.

12. The instrument as set forth in claim 1, further comprising:

means for controlling predetermined operational characteristics of the instrument.

13. The instrument as set forth in claim 1, further comprising:

coupled to the truncated tip, waveguide means for refocusing the beam from the tip to a distal end of the waveguide means.

14. The instrument as set forth in claim 1, comprising:

the transducer is a piezoelectric element mounted directly to the applicator.

15. The instrument as set forth in claim 1, comprising:

the applicator has outer boundary wider than the taper of a sonic beam pattern imposed by the transducer in order to minimizes reflections and mode conversions at the boundary.

16. The instrument as set forth in claim 1, comprising:

the instrument is battery-powered.

17. The instrument as set forth in claim 1, comprising:

the applicator is removable from the instrument.