Self-cooled ultrasonic applicator for medical applications

• US 6,666,835 B2
• Filed: 03/08/2002
• Issued: 12/23/2003
• Est. Priority Date: 05/14/1999
• Status: Expired due to Fees

• Current Assignee: Washington University In St Louis
• Original Assignee: University of Washington
• Inventors: Martin, Roy W., Proctor, Andrew Hollis
• Primary Examiner(s): Smith, Ruth S.
• Application Number:
  US10/094,451
• Publication Number:
  US 20030171700A1
• Time in Patent Office: 655 Days
• Field of Search: 601/2-4, 600/439, 600/459, 604/22, 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 2018/00011 with fluids
• CPC Class Codes: A61B 2018/00017 with gas
• CPC Class Codes: A61B 2018/00023 closed, i.e. without wound contact by the fluid
• 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: 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: A61N 7/02 Localised ultrasound hyperthermia hyperthermia in general A61F7/00
• 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. Alternative embodiments employing cooling technology are also described.

Claims

1. A method for producing a therapeutic, high intensity, focused, ultrasonic energy pattern in living tissue, the method comprising:

generating a sonic wave with a transducer;

actively cooling the transducer without interfering with the sonic wave;

focusing the sonic wave via a solid material coupler coupled to the transducer such that it converges towards a focal point in the solid material;

truncating the solid material behind the focal point;

refocusing the beam with a lens at the focal point to provide a predetermined focal region externally of the solid material; and

coupling the lens to the living tissue such that the focal region is directed to a target point within the living tissue.

2. The method as set forth in claim 1 wherein said cooling further comprises:

moving a coolant passed said transducer.

3. The method as set forth in claim 1, the coupler having a predetermined geometric apex, wherein the sonic wave is transmitted through the coupler within a predetermined external boundary layer of the coupler;

subjecting the wave to a lens means for redirecting the sonic wave; and

coupling the lens means directly to the living tissue such that the focal region is directed to a target within the living tissue.

4. The method as set forth in claim 3 comprising:

tailoring transducer geometry and coupler geometry and transducer generating frequency to specific therapeutic tasks.

5. A high intensity focused ultrasonic device for performing medical procedures, comprising:

generating means for generating a focused ultrasound beam;

mounted to the generating means, transmitting means for transmitting the beam toward a focal point within the transmitting means, wherein the transmitting means is formed of a solid material;

redirecting lens means for redirecting the beam, wherein the lens means is located between the generating means and the focal point such that the focal point is external to the transmitting means solid material; and

means for cooling the device.

6. The device as set forth in claim 5 further comprising:

the means for cooling is provided substantially adjacent said generating means.

7. The device as set forth in claim 5 further comprising:

the means for cooling includes a moving coolant for carrying heat away from said device.

8. The device as set forth in claim 7 further comprising:

the means for cooling is located such that said beam is unaffected.

9. The device as set forth in claim 5 comprising:

the transmitting means is a semi-cone of a solid material having low acoustic attenuation mounted such that coolant flow channels forming said cooling means are located such that there is no interference with said beam.

10. A high intensity focused ultrasound medical instrument comprising:

a handle;

mounted to the handle, a housing including a cavity;

in the housing, a transducer having a substantially concave geometry for providing a focused ultrasonic beam from a transducer concave frontside thereof, proximate said transducer, at least one channel for carrying a coolant adapted for absorbing heat generated by the transducer, 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.

11. The instrument as set forth in claim 10 wherein the handle is adapted for providing a conduit for coupling power and the coolant to the housing.

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

a cooling subsystem including means for pumping the coolant, means for transferring the coolant to and from the channel using the means for pumping, including means for radiating heat from the coolant during said transferring.

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

means for controlling operational characteristics of the instrument, including controlling functions of said cooling subsystem.