EFFICIENT ULTRASOUND FOCUSING

• US 20110270136A1
• Filed: 04/28/2010
• Published: 11/03/2011
• Est. Priority Date: 04/28/2010
• Status: Active Grant

• Current Assignee: InSightec Ltd.
• Original Assignee: InSightec Ltd.
• Inventors: Vitek, Shuki, Hertzberg, Yoni
• Granted Patent: US 8,932,237 B2
• Time in Patent Office: Days
• US Class Current: 601/2
• CPC Class Codes: A61B 2034/105 Modelling of the patient, e.g. for ligaments or bones
• CPC Class Codes: A61B 2090/374 NMR or MRI
• CPC Class Codes: A61N 2007/0065 Concave transducers
• CPC Class Codes: A61N 2007/0095 by modifying an excitation signal
• CPC Class Codes: A61N 7/02 Localised ultrasound hyperthermia hyperthermia in general A61F7/00

Abstract

Ultrasound focusing may be improved by combining knowledge of the target tissue and/or focusing arrangement with focus measurements.

Claims

1. A method of focusing a phased array of ultrasound transducer elements into a target tissue using a sonication model, the method comprising:

based at least in part on the model, grouping the transducer elements into sub-arrays and determining relative phases of the transducer elements within each sub-array,

driving the transducer elements of the sub-arrays at the respective relative phases, thereby generating sub-foci; and

determining whether the sub-foci constructively interfere and, if not, adjusting the phases of the transducer elements to cause constructive interference of the sub-foci.

2. The method of claim 1, wherein the sonication model comprises a geometric parameter indicative of a relative arrangement between the phased array and the target tissue.

3. The method of claim 1, wherein the sonication model comprises a target focus location.

4. The method of claim 1, wherein the sonication model comprises at least one of a material parameter or a geometric parameter of the target tissue.

6. The method of claim 1, wherein the grouping is based on incidence angles of ultrasound emitted from the transducer elements on a target tissue interface.

7. The method of claim 1, wherein, for at least one of the sub-arrays, determining the relative phases of the transducer elements therein comprises computing the relative phases based on the sonication model.

8. The method of claim 1, wherein, for at least one of the sub-arrays, determining the relative phases of the transducer elements therein comprises driving the transducer elements so as to generate a sub-focus, measuring a quality of the focus, and adjusting the relative phases to improve the quality of the focus.

9. The method of claim 1, wherein determining whether the sub-foci constructively interfere comprises determining whether the sub-foci are in phase.

10. The method of claim 9, wherein adjusting the phases of the transducer elements comprises, for each sub-array, applying phase shifts of equal magnitude to the transducer elements therein, the phase shifts applied to respective sub-arrays being chosen so as to bring the sub-foci in phase.

11. The method of claim 1, wherein determining whether the sub-foci constructively interfere comprises determining whether the sub-foci are co-located.

12. The method of claim 11, wherein adjusting the phases of the transducer elements comprises applying phase gradients across the transducer elements of each sub-array so as to co-locate the sub-foci.

13. The method of claim 1, wherein determining whether the sub-foci constructively interfere comprises measuring a quality of a global focus formed by the sub-foci.

5. (canceled)

14. (canceled)

15. A method of focusing a phased array of ultrasound transducer elements into a target tissue using a model of the target tissue, the model comprising at least one model parameter, the method comprising:

for each of a plurality of value sets for the at least one model parameter, (i) computing, based at least in part on the model and a target focus location in the target tissue, relative phases of the transducer elements, (ii) driving the transducer elements at the computed relative phases so as to generate an ultrasound focus at the target focus location, and (iii) measuring a quality of the focus; and

selecting, among the plurality of value sets, the set associated with the highest focus quality.

19. The method of claim 15, wherein the at least one model parameter comprises a velocity of sound.

20. The method of claim 15, wherein the at least one model parameter comprises a plurality of model parameters and each of the value sets comprises a value for each of the model parameters.

16-18. -18. (canceled)

21-23. -23. (canceled)

24. A system for focusing ultrasound into a target tissue using a sonication model, the system comprising:

a phased array of ultrasound transducer elements for generating an ultrasound focus in the target tissue;

an imaging system for imaging the ultrasound focus; and

in communication with the imaging system and the phased array of transducer elements, a control facility configured to (i) receive data associated with the sonication model, (ii) based at least in part on the data, compute relative phases of the transducer elements, (iii) drive the transducer elements at the relative phases so as to generate the ultrasound focus, and (iv) based at least in part on an image of the ultrasound focus, adjust the relative phases so as to improve the ultrasound focus.

25. The system of claim 24, wherein the imaging system is a magnetic resonance imaging system.

26. The system of claim 24, wherein the control facility is configured to group the transducer elements into sub-arrays and to compute relative phases of the transducer elements within each sub-array.

27. The system of claim 26, wherein the control facility is configured to adjust the relative phases so as to cause constructive interference of sub-foci generated by the sub-arrays.

28-30. -30. (canceled)

31. For use in connection with an imaging system, a system for focusing ultrasound into a target tissue using a sonication model, the system comprising:

a phased array of ultrasound transducer elements for generating an ultrasound focus in the target tissue; and

a control facility configured to (i) receive data associated with the sonication model, (ii) based at least in part on the data, compute relative phases of the transducer elements, (iii) drive the transducer elements at the relative phases so as to generate the ultrasound focus, and (iv) based at least in part on an image of the ultrasound focus provided by the imaging system, adjust the relative phases so as to improve the ultrasound focus.

32. (canceled)