Diffuse focus ultrasound hyperthermia system

• US 4,893,624 A
• Filed: 06/21/1988
• Issued: 01/16/1990
• Est. Priority Date: 06/21/1988
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Lele, Padmakar P.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US07/209,520
• Time in Patent Office: 574 Days
• Field of Search: 128/399, 128/24 A, 128/660.03, 128/660.09, 128/661.01, 73/642, 73/618
• US Class Current: 601/3
• CPC Class Codes: A61B 2017/22028 arrays, e.g. phased arrays
• CPC Class Codes: A61N 2007/006 Lenses
• 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

A system for delivering ultrasound hyperthermic therapy to a subject includes a plurality of piezoelectric ultrasound transducer elements arranged in a two-dimensional array to provide multiple sources of ultrasonic energy, and variable activation elements for activating the transducer elements individually and at variable electrical energy levels. A plurality of lens elements is provided for transmitting the multiple sources of ultrasonic energy to the subject, in conjunction with focusing elements which individually vary the attitude of the lens elements to change the focal regions of the individual lenses. The transducer elements and lens elements can be corresponding "pie-slice" sectors arranged in a circular array, in combination with a central circular transducer and lens.

Claims

1. An ultrasonic hyperthermia system for delivering hyperthermic therapy to a subject, the system comprising:

a plurality of piezoelectric transducer elements arranged in a two-dimensional array to provide multiple sources of ultrasonic energy;

variable activation means for activating the transducer elements individually and at variable electrical energy levels to permit the multiple sources of ultrasonic energy to vary in intensity;

a further plurality of lens elements, coupled to the plurality of transducer elements, to transmit the multiple sources of ultrasonic energy to the subject as a diffuse-focus beam having a selected dimension in a direction substantially perpendicular to a direction of propagation; and

focusing means for dynamically varying the position of the lens elements individually to permit variations in the focal regions of the multiple sources of ultrasonic energy, said variations in focal regions including variations in the selected dimension of the diffuse-focus beam.

2. The system of claim 1 wherein the transducer elements are arranged in a circular array.

3. The system of claim 2 wherein the transducer elements are pie-shaped elements.

4. The system of claim 3 wherein the plurality of lens elements includes pie-shaped lens elements adopted to be disposed between the transducer elements and the subject.

5. The system of claim 1 wherein the focusing means further includes tilting means for tilting the individual lens elements to change their focal regions.

6. The system of claim 5 wherein the tilting means includes means for tilting the individual lens elements to change the focal depth of the individual lens elements.

7. The system of claim 1, further including rotating means, supportingly connected to the array of transducer elements, for rotating the array of transducer elements through a selected orbital path.

8. An ultrasonic hyperthermia system for delivering hyperthermic therapy to a subject, the system comprising:

a plurality of piezoelectric transducer elements arranged in a two-dimensional array to provide multiple sources of ultrasonic energy;

variable activation means for activating the transducer elements individually and at variable electrical energy levels to permit the multiple sources of ultrasonic energy to vary in intensity;

a further plurality of lens elements, coupled to the plurality of transducer elements, to transmit the multiple sources of ultrasonic energy to the subject; and

focusing means for varying the position of the lens elements individually to permit variations in the focal regions of the multiple sources of ultrasonic energy, the focusing means including tilting means for tilting the individual lens elements to change their focal regions, the tilting means including (i) means for tilting the individual lens elements to change the focal depth of the individual lens elements, and (ii) means for introducing a substantially randomized perturbation in the tilt of the individual lens elements.

9. An ultrasonic hyperthermia system for delivering hyperthermic therapy to a subject, the system comprising:

a plurality of piezoelectric transducer elements arranged in a two-dimensional array to provide multiple sources of ultrasonic energy;

variable activation means for activating the transducer elements individually and at variable electrical energy levels to permit the multiple sources of ultrasonic energy to vary in intensity;

a further plurality of lens elements to transmit the multiple sources of ultrasonic energy to the subject; and

focusing means for varying the position of the lens elements individually to permit variations in the focal regions of the multiple sources of ultrasonic energy, the focusing means including wedge focusing means for selectively positioning a wedge of ultrasound transmitting medium between an individual lens element and a corresponding transducer element.

10. An ultrasonic hyperthermia system for delivering hyperthermic therapy to a subject, the system comprising:

a plurality of ultrasonic energy generating modules, each module including

(i) a plurality of piezoelectric transducer elements arranged in a two-dimensional array to provide multiple sources of ultrasonic energy;

(ii) variable activation means for activating the transducer elements individually and at variable electrical energy levels to permit the multiple sources of ultrasonic energy to vary in intensity;

(iii) a further plurality of lens elements, coupled to the plurality of transducer elements, to transmit the multiple sources of ultrasonic energy to the subject; and

(iv) focusing means for varying the position of the lens elements individually to permit variations in the focal regions of the multiple sources of ultrasonic energy.

11. The system of claim 10, further including scanning means, supportingly connected to said ultrasonic energy generating modules, for scanning said ultrasound generating modules across a selected area.

12. The system of claim 10, further including amplitude shading means for selectively varying, in accordance with a selected geometric pattern, the amplitude of ultrasonic energy generated by individual transducer elements.

13. The system of claim 10, further including rotating means, supportingly connected to said ultrasonic energy generating modules, for rotating the ultrasonic energy generating modules through a selected orbital path.

14. An ultrasonic hyperthermia system for delivering hyperthermic therapy to a subject, the system comprising:

a plurality of piezoelectric transducer elements arranged in a two-dimensional array to provide multiple sources of ultrasonic energy;

variable activation means for activating the transducer elements individually and at variable electrical energy levels to permit the multiple sources of ultrasonic energy to vary in intensity;

a further plurality of lens elements to transmit the multiple sources of ultrasonic energy to the subject;

focusing means for varying the position of the lens elements individually to permit variations in the focal regions of the multiple sources of ultrasonic energy;

rotating means, supportingly connected to the array of transducer elements, for rotating the array of transducer elements through a selected orbital path; and

amplitude shading means, responsive to the instantaneous angular position of the array of transducer elements, for selectively varying the amplitude of ultrasonic energy generated by individual transducer elements.

15. A method for delivering hyperthermic therapy to a subject, the method comprising the steps of:

arranging a plurality of piezoelectric transducer elements in a two-dimensional array to provide multiple sources of ultrasonic energy;

activating the transducer elements individually and at variable electrical energy levels to permit the multiple sources of ultrasonic energy to vary in intensity;

positioning a further plurality of lens elements to transmit the multiple sources of ultrasonic energy to the subject as a diffuse-focus beam having a selected dimension in a direction substantially perpendicular to a direction of propagation; and

varying the position of the lens elements individually to permit variations in the focal regions of the multiple sources of ultrasonic energy, said variations in focal regions including variations in the selected dimension of the diffuse-focus beam.

16. The method of claim 15 wherein the step of arranging the plurality of piezoelectric transducer elements includes the step of arranging the transducer elements in a circular array.

17. The method of claim 15 further comprising the step of configuring the transducer elements as pie-shaped transducer elements.

18. The method of claim 17, further comprising the step of configuring the lens elements as pie-shaped lens elements disposed between the transducer elements and the subject.

19. The method of claim 15 wherein the step of varying the position of the lens elements includes the step of tilting the individual lens elements to change their focal regions.

20. The method of claim 19 wherein the step of varying the position of the lens elements includes the step of tilting the individual lens elements to change the focal depth of the individual lens elements.

21. The method of claim 15, further including the step of rotating the array of transducer elements through a selected orbital path.

22. A method for delivering hyperthermic therapy to a subject, the method comprising the steps of:

arranging a plurality of piezoelectric transducer elements in a two-dimensional array to provide multiple sources of ultrasonic energy;

activating the transducer elements individually and at variable electrical energy levels to permit the multiple sources of ultrasonic energy to vary in intensity;

positioning a further plurality of lens elements to transmit the multiple sources of ultrasonic energy to the subject; and

varying the position of the lens elements individually to permit variations in the focal regions of the multiple sources of ultrasonic energy, wherein the step of varying the position of the lens elements including the step of tilting the individual lens elements to change their focal regions, and the step of tilting the individual lens elements includes the step of introducing a substantially randomized perturbation in the tilt of the individual lens elements.

23. A method for delivering hyperthermic therapy to a subject, the method comprising the steps of:

arranging a plurality of piezoelectric transducer elements in a two-dimensional array to provide multiple sources of ultrasonic energy;

activating the transducer elements individually and at variable electrical energy levels to permit the multiple sources of ultrasonic energy to vary in intensity;

positioning a further plurality of lens elements to transmit the multiple sources of ultrasonic energy to the subject; and

varying the position of the lens elements individually to permit variations in the focal regions of the multiple sources of ultrasonic energy, wherein the step of varying the position of the lens elements includes the step of selectively positioning a wedge of ultrasound transmitting medium between an individual lens element and a corresponding transducer element.

24. An ultrasonic hyperthermia method for delivering hyperthermic therapy to a subject, the method comprising the steps of:

arranging a plurality of piezoelectric transducer elements in a plurality of two-dimensional arrays to provide multiple sources of ultrasonic energy;

activating the transducer elements individually and at variable electrical energy levels to permit the multiple sources of ultrasonic energy to vary in intensity;

configuring a further plurality of lens elements to transmit the multiple sources of ultrasonic energy to the subject;

varying the position of the lens elements individually to permit variations in the focal regions of the multiple sources of ultrasonic energy; and

configuring the plurality of arrays as a plurality of ultrasonic energy generating modules.

25. The method of claim 24, further including the step of scanning the ultrasound generating modules across a selected area.

26. The method of claim 24, further including the step of selectively varying, in accordance with a selected geometric pattern, the amplitude of ultrasonic energy generated by individual transducer elements.

27. The method of claim 24, further including the step of rotating the ultrasonic energy generating modules through a selected orbital path.

28. A method for delivering hyperthermic therapy to a subject, the method comprising the steps of:

arranging a plurality of piezoelectric transducer elements in a two-dimensional array to provide multiple sources of ultrasonic energy;

activating the transducer elements individually and at variable electrical energy levels to permit the multiple sources of ultrasonic energy to vary in intensity;

positioning a further plurality of lens elements to transmit the multiple sources of ultrasonic energy to the subject;

varying the position of the lens elements individually to permit variations in the focal regions of the multiple sources of ultrasonic energy;

rotating the array of transducer elements through a selected orbital path;

responding to the instantaneous angular position of the array of transducer elements; and

selectively varying the amplitude of ultrasonic energy generated by individual transducer elements, responsive to the instantaneous angular position of the array of transducer elements.