THERMAL THERAPY APPARATUS AND METHOD USING FOCUSED ULTRASONIC SOUND FIELDS

• US 20110319793A1
• Filed: 06/28/2011
• Published: 12/29/2011
• Est. Priority Date: 06/29/2010
• Status: Active Grant

• Current Assignee: Sunnybrook Research Institute
• Original Assignee: Sunnybrook Research Institute
• Inventors: Hynynen, Kullervo Henrik
• Granted Patent: US 10,576,304 B2
• Time in Patent Office: Days
• US Class Current: 601/2
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2017/00106 ultrasonic
• CPC Class Codes: A61N 2007/0073 using multiple frequencies
• CPC Class Codes: A61N 2007/0095 by modifying an excitation signal
• CPC Class Codes: A61N 2007/027 with multiple foci created simultaneously
• CPC Class Codes: A61N 7/02 Localised ultrasound hyperthermia hyperthermia in general A61F7/00

Abstract

Apparatus and method for delivering increased amounts of energy to localized treatment zones in a target tissue volume are provided. In some instances the non-linear wave propagation and other properties of the treatment apparatus and propagation medium as well as novel beam forming and control of the treatment apparatus are employed to generate extended focal zones for efficient treatment of a condition in a patient.

Claims

1. A system for delivering acoustical energy for therapy of a region of the body, comprising:

a first acoustical source, having a first characteristic operating frequency and controllably delivering acoustic energy at substantially said first characteristic operating frequency to a target location;

a second acoustical source, having a second characteristic operating frequency being lower than said first characteristic operating frequency, and controllably delivering acoustic energy at substantially said second characteristic operating frequency to said target location; and

a controller adapted and arranged to control one or both of said first and second acoustical sources and configured to cause said first acoustical source to deliver its acoustic energy to said target location at a time when said second acoustical source is providing a positive acoustic pressure at said target location.

2. The system of claim 1, said first acoustical source comprising a first focused ultrasound transducer designed to operate substantially at or about said first characteristic operating frequency.

3. The system of claim 1, said second acoustical source comprising a second focused ultrasound transducer designed to operate substantially at or about said second characteristic operating frequency.

4. The system of claim 1, each of said first and second acoustical sources comprising a plurality of elements of a phased array so that a first group of elements acts cooperatively to deliver acoustic energy at substantially said first characteristic operating frequency to said target location, and said second group of elements acts cooperatively to deliver acoustic energy at substantially said second characteristic operating frequency to said target location.

5. The system of claim 1, wherein said first acoustical source comprises a first array of elements in a first phased array and said second acoustical source comprises a second array of elements in a second phased array.

6. The system of claim 1, said first characteristic operating frequency being in a range of 100 kilohertz (kHz) to 10 megahertz (MHz).

7. The system of claim 1, said second characteristic operating frequency being in a range of 1 to 500 kilohertz (kHz).

8. The system of claim 1, further comprising a coupling medium disposed in a portion of a path between said first acoustical source and said region of the body, said portion of said path being more proximal to said first acoustical source than to said region of the body, and said coupling medium having a characteristic to encourage nonlinear propagation of acoustic waves from said first acoustical source.

9. The system of claim 1, further comprising a first signal generator for generating a driving signal at substantially said first characteristic operating frequency to drive said first acoustical source.

10. The system of claim 9, further comprising a second signal generator for generating a driving signal at substantially said second characteristic operating frequency to drive said second acoustical source.

11. The system of claim 1, further comprising a first amplifier circuit for controlling a power of an electrical signal used to drive said first acoustical source.

12. The system of claim 1, further comprising a second amplifier circuit for controlling a power of an electrical signal used to drive said second acoustical source.

13. The system of claim 11, said first amplifier circuit adapted to drive said first acoustical source so as to substantially cause a nonlinear distortion of a propagated acoustical wave at said first characteristic operating frequency, wherein said distorted acoustical wave includes higher frequency components than said first characteristic operating frequency.

14. The system of claim 13, said first amplifier circuit adapted to cause a shock wave from said first acoustical source to arrive at or near said target location.

15. The system of claim 1, said target location being extended in space, wherein said first acoustical source is adapted to deliver acoustical energy to a plurality of focal points simultaneously to spatially extend a focal zone long within said extended target location.

16. The system of claim 1, said second acoustical source designed and adapted to provide an enhancing acoustical signal at substantially said second characteristic operating frequency to enhance a conversion of acoustic to thermal energy of acoustic waves from said first acoustical source within said target location.

17. A method for providing ultrasonic therapy to a target volume, comprising:

providing a first driving signal at a first characteristic operating frequency and within selected temporal windows to drive a first acoustical source;

providing a second driving signal at a second characteristic operating frequency to drive a second acoustical source, said second characteristic operating frequency being lower than said first characteristic operating frequency;

controlling said first driving signal so that said selected temporal windows deliver a first ultrasonic dose of energy to said target volume at a time substantially coincident with a time that said second acoustical source delivers a maximal acoustic pressure to said target volume; and

controlling an amplitude of said first and second driving signals so that the first ultrasonic dose of energy in said target volume experiences substantial nonlinear distortion on its way from said first acoustical source to said target volume.

18. The method of claim 17, further comprising gating said first driving signal to selectably control the temporal window in which the first acoustical source is driven.

19. The method of claim 17, further comprising monitoring a thermal effect of said therapy in or around said target volume.

20. The method of claim 17, said second ultrasound signal providing a plurality of ultrasound signal components, and further comprising controlling a phase and an amplitude of each of said plurality of ultrasound signal components to cause constructive interference of acoustic waves from said plurality of ultrasound signal components in said target volume substantially when ultrasound waves from the first driving signal passes through the target volume.

21. The method of claim 17, said first and second driving signals being provided by a same ultrasonic source or array.

22. A method for treating a disease in diseased tissue using an ultrasonic array of transducer elements, comprising:

delivering a first amount of ultrasonic energy at a first energy level from a first group of ultrasonic array elements driven at a first characteristic operating frequency and focusing said first amount at a first focal location within said diseased tissue;

delivering a second amount of ultrasonic energy at a second energy level from a second group of ultrasonic array elements driven at a second characteristic operating frequency and focusing said second amount at a second focal location within said diseased tissue;

said focusing of said first and second amounts of ultrasonic energy being performed substantially along a line defining a direction of propagation of said ultrasonic energy and said delivery of said first and second amounts of ultrasonic energy carried out using respective first and second energy levels sufficient to cause substantial nonlinear wave form distortion within an extended focal zone encompassing said first and second focal locations.

23. The method of claim 22, wherein said first and second characteristic operating frequencies are substantially different from one another.

24. The method of claim 22, wherein said first and second characteristic operating frequencies are substantially the same.

25. The method of claim 22, wherein said line defining the direction of propagation comprises an axis of symmetry of an ultrasonic array and said extended focal zone is substantially disposed along said line with a first end thereof proximal to said array and a second end thereof distant from said array.

26. The method of claim 22, said delivering of said first and second amounts of energy forming said respective first and second focal locations separately in time, one following the other.

27. The method of claim 22, said delivering of said first and second amounts of energy forming said respective first and second focal locations simultaneously in time.