METHOD AND APPARATUS FOR FEEDBACK CONTROL OF HIFU TREATMENTS

• US 20100106019A1
• Filed: 10/26/2009
• Published: 04/29/2010
• Est. Priority Date: 10/24/2008
• Status: Active Grant

• Current Assignee: Mirabilis Medica, Inc.
• Original Assignee: Mirabilis Medica, Inc.
• Inventors: Emery, Charles D., Reed, Justin A., Friemel, Barry, Parsons, Jessica E., Darlington, Gregory P., Etchells, Tim
• Granted Patent: US 8,480,600 B2
• Time in Patent Office: Days
• US Class Current: 600/439
• CPC Class Codes: A61B 17/42 Gynaecological or obstetrical instruments or methods ligaturing clamps or clips for the umbilical cord A61B17/122; curettage A61B17/320708; dilators A61M29/00
• CPC Class Codes: A61B 2017/00119 alarm; indicating an abnormal situation
• CPC Class Codes: A61B 2090/378 using ultrasound
• CPC Class Codes: A61B 8/08 Detecting organic movements or changes, e.g. tumours, cysts, swellings A61B8/02 - A61B8/06 take precedence
• CPC Class Codes: A61N 7/02 Localised ultrasound hyperthermia hyperthermia in general A61F7/00

Abstract

HIFU therapy to a desired tissue site is controlled based on detected changes in one or more characteristics of a received backscatter signal resulting from exposure of the tissue to HIFU or other interrogation signals. In one embodiment, the bloom of backscatter signals outward from a treatment region (e.g., towards the HIFU transducer) is detected and monitored. Once the bloom reaches a predetermined location, treatment is stopped. Other signal characteristics such as angular distribution of frequency components in the backscatter signal, changes in reflection, power required to saturate a tissue characteristic, changes in attenuation and changes in a cumulative energy distribution function of the backscatter signal that change as a result of the application of HIFU power are also used to control the delivery of HIFU signals in accordance with other embodiments of the disclosed technology.

Claims

1. A high intensity focused ultrasound (HIFU) system for treating tissue at a treatment site, comprising:

a HIFU transducer and controller for delivering HIFU signals into a treatment site;

a receiver for receiving backscatter signals; and

a processor that is programmed to detect changes in the backscatter signals that result from the delivery of HIFU signals into the treatment site, wherein the processor is programmed to produce a feedback control signal that is used to control the delivery of HIFU signals into the treatment site based on the detected changes in the backscatter signal.

2. The system of claim 1, wherein the processor is programmed to detect movement of a leading edge of the backscatter signal toward the HIFU transducer.

3. The system of claim 1, wherein the processor is programmed to detect changes in an angular distribution of frequency components in the backscatter signal.

4. The system of claim 1, wherein the processor is programmed to detect changes in attenuation of the tissue at the treatment site from the backscatter signals.

5. The system of claim 1, wherein the processor is programmed to detect changes in a power level required to saturate a characteristic of the backscatter signal.

6. The system of claim 1, wherein the processor is programmed to detect changes in a cumulative energy distribution function of the backscatter signal.

7. The system of claim 1, wherein the processor is programmed to process the backscattered signals to emphasize variations in the backscatter signals.

8. The system of claim 1, wherein the processor is programmed to produce an averaged backscatter signal from a number of individual backscatter signals, wherein the average backscatter signals are weighted to emphasize depths within the individual backscatter signals that exhibit variances in amplitude.

9. The system of claim 8, wherein the individual backscatter signals are weighted to emphasize individual backscatter signals with greater energy.

10. The system of claim 1, further comprising a mechanism to steer the treatment zone of the HIFU transducer around a perimeter of an elemental treatment volume, wherein the processor is programmed to monitor backscatter signals as the treatment zone is moved along the perimeter of an elemental treatment volume.

11. The system of claim 1, wherein the processor is programmed to supply the feedback control signal to the HIFU controller to modify HIFU treatment.

12. The system of claim 1, wherein the processor is programmed to supply the feedback control signal to an alarm that can be perceived by a physician.

13. The system of claim 1, wherein the backscatter signals are signals created in response to the HIFU signals delivered to the treatment site.

14. The system of claim 1, further comprising a transducer for delivering an interrogation signal to the treatment site, wherein the backscatter signals are signals created in response to the interrogation signal delivered to the treatment site.

15. A high intensity focused ultrasound (HIFU) system for treating tissue at a treatment site, comprising:

a HIFU transducer and controller for delivering HIFU signals into a treatment site;

an imaging transducer and a receiver for receiving backscatter signals created as a result of the delivered HIFU or interrogation signals; and

a processor that is programmed to detect movement of an image of the backscatter signals toward the HIFU transducer as HIFU signals are delivered into the treatment site, wherein the processor is programmed to produce a feedback control signal that is used to control the delivery of HIFU signals into the treatment site based on the detected movement in the backscatter signal.

16. A method for treating tissue with high intensity focused ultrasound (HIFU) signals, comprising:

delivering HIFU signals to the treatment site;

receiving backscatter signals; and

detecting changes in the backscatter signals that result from the delivery of HIFU signals into the treatment site, wherein the processor is programmed to produce a feedback control signal that is used to control the delivery of HIFU signals into the treatment zone based on the detected changes in the backscatter signal.