SYSTEMS AND METHODS FOR CONTROLLING ULTRASOUND ENERGY TRANSMITTED THROUGH NON-UNIFORM TISSUE AND COOLING OF SAME

• US 20100179425A1
• Filed: 01/13/2009
• Published: 07/15/2010
• Est. Priority Date: 01/13/2009
• Status: Abandoned Application

• Current Assignee: InSightec Ltd.
• Original Assignee: InSightec Ltd.
• Inventors: Zadicario, Eyal
• Application Number:
  US12/352,932
• Publication Number:
  US 20100179425A1
• Time in Patent Office: Days
• US Class Current: 600/438
• CPC Class Codes: A61B 2018/00023 closed, i.e. without wound contact by the fluid
• CPC Class Codes: A61B 2090/374 NMR or MRI
• CPC Class Codes: A61B 2090/3762 using computed tomography systems [CT]
• CPC Class Codes: A61B 8/0816 using echo-encephalography
• CPC Class Codes: A61B 8/585 Automatic set-up of the device
• CPC Class Codes: A61N 2007/0078 with multiple treatment transducers
• CPC Class Codes: A61N 7/02 Localised ultrasound hyperthermia hyperthermia in general A61F7/00

Abstract

The emission intensities of transducer elements of an ultrasound transducer array are controlled based on anatomical characteristics of non-uniform tissue regions, e.g., regions of a skull, and a pre-determined threshold.

Claims

1. A method for controlling intensities in a transducer array comprising a plurality of transducer elements, the method comprising:

determining anatomical characteristics of non-uniform tissue regions to be traversed using focused ultrasound, each of the transducer elements being primarily associated with a corresponding tissue region;

determining, for each of the transducer elements, a preferred intensity of ultrasound energy at a target region, the intensity being based on anatomical characteristics of the corresponding non-uniform tissue region and a pre-determined energy threshold associated therewith; and

driving the transducer elements at their respective preferred intensities, thereby directing ultrasound energy through the non-uniform tissue to the focus, the directed ultrasound energy emitted by the transducer array being non-uniform across the transducer array and maximized while satisfying the pre-determined thresholds.

2. The method of claim 1, wherein the anatomical characteristics comprise at least one of a thickness of the non-uniform tissue, a density of the non-uniform tissue, a density distribution, an entrance point of a ray emitted by a transducer element into the non-uniform tissue, or an exit point of a ray emitted by the transducer element from the non-uniform tissue.

3. The method of claim 1, wherein the pre-determined threshold is a maximum temperature.

4. The method of claim 3, wherein the intensity of ultrasound energy emitted by the plurality of transducer elements is further based at least in part on an increase in temperature of the non-uniform tissue region.

5. The method of claim 3, further comprising:

determining an actual temperature of the non-uniform tissue during driving of the transducer array;

comparing the actual temperature to the maximum temperature; and

cooling the non-uniform tissue if the actual temperature is greater than the maximum temperature.

6. The method of claim 5, wherein the actual temperature is determined by magnetic resonance thermometry, and further comprising deactivating the ultrasound transducer if the actual temperature is greater than the maximum temperature.

7. The method of claim 3, further comprising

circulating a cooling fluid within a fluid interface integral with the ultrasound transducer and positioned between the ultrasound transducer and the non-uniform tissue;

measuring a temperature of the cooling fluid;

comparing the measured temperature to a maximum cooling fluid temperature; and

generating an output signal representing the results of the comparison.

8. The method of claim 1 wherein the non-uniform tissue comprises skull tissue.

9. The method of claim 7, wherein the output signal is displayed to an operator of the transducer array.

10. The method of claim 7, wherein the cooling fluid circulates within the interface.

11. The method of claim 1, wherein the intensity of ultrasound energy emitted by individual transducer elements ranges from about 0.0 Watt to about 10 Watts.

12. The method of claim 1, wherein a difference between a minimum intensity and a maximum intensity of ultrasound energy emitted by individual transducer elements varies by about 0.0 Watt to about 10 Watts.

13. A system for controlling an intensity of a transducer array having a plurality of transducer elements, the system comprising:

an imaging system configured to determine anatomical characteristics of non-uniform tissue regions;

a controller operably, coupled to the imaging system, for determining a maximum allowable intensity of ultrasound energy emitted by each transducer element into a corresponding non-uniform tissue region based the determined anatomical characteristics and a pre-determined threshold associated with the tissue regions; and

drive circuitry for driving the transducer elements to emit ultrasound energy at the determined maximum intensities through the non-uniform tissue.

14. The system of claim 13 further comprising a computed tomography imaging system for determining the anatomical characteristics of the non-uniform tissue regions.

15. The system of claim 14 further comprising a magnetic resonance imaging system, associated with the computed tomography system, for localizing the plurality of transducer elements relative to the non-uniform tissue regions.

16. The system of claim 13, wherein the predetermined threshold is a maximum temperature of a non-uniform tissue region.

17. The system if claim 13 wherein the non-uniform tissue regions comprise skull tissue.

18. The system of claim 16, wherein the magnetic resonance imaging system is configured to determine an actual temperature of the non-uniform tissue during driving of the plurality of transducer elements, the controller being configured to generate an output indicating when the actual temperature of the non-uniform tissue is greater than the maximum temperature.

19. The system of claim 16, wherein individual transducer elements are independently controllable such that the temperature of each non-uniform tissue region does not exceed the maximum temperature.

20. The system of claim 13, further comprising a fluid interface integral with the ultrasound transducer and operably coupled to the controller, wherein the fluid interface is positionable around the non-uniform tissue region and configured to facilitate circulation of cooling fluid about the non-uniform tissue.

21. The system of claim 20, further comprising a temperature sensor positioned within the fluid interface and in communication with the controller, the temperature sensor being configured to measure a temperature of the cooling fluid circulating within the fluid interface.

22. The system of claim 21, wherein the fluid circulates within the interface in a continuous fashion.