Method and system to synchronize acoustic therapy with ultrasound imaging

• US 20070055155A1
• Filed: 08/17/2005
• Published: 03/08/2007
• Est. Priority Date: 08/17/2005
• Status: Active Grant

• Current Assignee: University of Washington
• Original Assignee: University of Washington
• Inventors: Bailey, Michael, Owen, Neil
• Granted Patent: US 7,621,873 B2
• Time in Patent Office: Days
• US Class Current: 600/439
• CPC Class Codes: A61B 8/00 Diagnosis using ultrasonic, sonic or infrasonic waves imaging of objects using sonar G01S15/00
• CPC Class Codes: A61B 8/4209 by using holders, e.g. positioning frames
• CPC Class Codes: A61B 8/4281 characterised by sound-transmitting media or devices for coupling the transducer to the tissue
• CPC Class Codes: A61B 8/543 involving acquisition triggered by a physiological signal
• CPC Class Codes: A61N 7/02 Localised ultrasound hyperthermia hyperthermia in general A61F7/00

Abstract

Interference in ultrasound imaging when used in connection with high intensity focused ultrasound (HIFU) is avoided by employing a synchronization signal to control the HIFU signal. Unless the timing of the HIFU transducer is controlled, its output will substantially overwhelm the signal produced by ultrasound imaging system and obscure the image it produces. The synchronization signal employed to control the HIFU transducer is obtained without requiring modification of the ultrasound imaging system. Signals corresponding to scattered ultrasound imaging waves are collected using either the HIFU transducer or a dedicated receiver. A synchronization processor manipulates the scattered ultrasound imaging signals to achieve the synchronization signal, which is then used to control the HIFU bursts so as to substantially reduce or eliminate HIFU interference in the ultrasound image. The synchronization processor can alternatively be implemented using a computing device or an application-specific circuit.

Claims

1. A method for synchronizing non-imaging ultrasound waves and ultrasound imaging waves produced by an ultrasound imaging system, so at least a portion of an ultrasound image produced by the ultrasound imaging system is free from interference due to the non-imaging ultrasound waves, comprising the steps of:

(a) producing an output signal in response to receiving scattered ultrasound imaging waves independently of the ultrasound imaging system;

(b) manipulating the output signal to generate a synchronization signal; and

(c) using the synchronization signal to selectively control generation of the non-imaging ultrasound waves, such that at least a portion of the ultrasound image is free from interference due to the non-imaging ultrasound waves.

2. The method of claim 1, wherein the non-imaging ultrasound waves comprise high intensity focused ultrasound (HIFU) waves.

3. The method of claim 2, wherein the step of producing the output signal comprises the step of using a HIFU transducer configured to generate the HIFU waves as a receiver to detect the scattered ultrasound imaging waves.

4. The method of claim 1, wherein the step of producing the output signal comprises the step of using a receiver to detect the scattered ultrasound imaging waves, the receiver being independent of an ultrasound imaging probe that generates the ultrasound imaging waves and of a transducer generating the non-imaging ultrasound waves.

5. The method of claim 1, wherein the step of producing the output signal comprises the step of using at least one of a receiver disposed proximate to an ultrasound imaging transducer of the ultrasound imaging system, and a receiver disposed proximate to a transducer generating the non-imaging ultrasound waves.

6. The method of claim 1, wherein the step of manipulating the output signal to generate the synchronization signal comprises the step of using a computing device to generate the synchronization signal.

7. The method of claim 1, wherein the step of manipulating the output signal to generate the synchronization signal comprises the step of using a synchronization circuit to generate the synchronization signal.

8. The method of claim 1, wherein the step of manipulating the output signal to generate the synchronization signal comprises the step of automatically generating the synchronization signal using at least one of a computing device and a synchronization circuit.

9. The method of claim 1, wherein the step of manipulating the output signal to generate the synchronization signal comprises the steps of:

(a) detecting the output signal;

(b) determining an envelope of the output signal; and

(c) generating a pulse for triggering a transducer that generates the non-imaging ultrasound waves.

10. The method of claim 9, wherein the step of manipulating the output signal to generate the synchronization signal further comprises the step of combining the pulse for triggering the transducer that generates the non-imaging ultrasound waves with a signal from a user control switch to generate the synchronization signal, such that the synchronization signal is used to selectively control the transducer that generates the non-imaging ultrasound waves only when a user has activated the user control switch, regardless of the existence of a pulse that has been generated based on the output signal.

11. The method of claim 1, wherein the step of manipulating the output signal to generate the synchronization signal comprises the steps of:

(a) amplifying the output signal;

(b) averaging a plurality of amplitudes defining the output signal to generate an averaged output signal;

(c) amplifying the averaged output signal;

(d) clamping the averaged output signal to insure that the averaged output signal does not exceed a maximum value, thereby generating a clamped signal;

(e) using the clamped signal to generate a pulsed signal for triggering a transducer that generates the non-imaging ultrasound waves; and

(f) combining the pulsed signal for triggering a transducer that generates the non-imaging ultrasound waves with a signal from a user control switch to generate the synchronization signal, such that the synchronization signal is used to selectively control the transducer that generates the non-imaging ultrasound waves only when a user has activated the user control switch.

12. The method of claim 1, wherein the step of manipulating the output signal to generate the synchronization signal comprises the step of eliminating false triggers.

13. A method for synchronizing non-imaging ultrasound waves and ultrasound imaging waves, so that interference in an ultrasound image due to the non-imaging ultrasound waves is limited to only a portion of the ultrasound image, comprising the steps of:

(a) using a transducer that generates non-imaging ultrasound waves to detect scattered ultrasound imaging waves, the transducer that generates non-imaging ultrasound waves producing an output signal that is indicative of the ultrasound imaging waves;

(b) manipulating the output signal to generate the synchronization signal;

(c) using the synchronization signal to selectively control generation of the non-imaging ultrasound waves by the transducer that generates non-imaging ultrasound waves, such that interference in the ultrasound image generated using the ultrasound imaging waves due to the non-imaging ultrasound waves is limited to only a portion of the ultrasound image.

14. The method of claim 13, wherein the step of manipulating the output signal to generate the synchronization signal comprises the step of automatically generating the synchronization signal using at least one of a computing device and a synchronization circuit.

15. The method of claim 13, wherein the step of manipulating the output signal to generate the synchronization signal comprises the steps of:

(a) amplifying the output signal;

(b) averaging a plurality of amplitudes defining the output signal to generate an averaged output signal;

(c) amplifying the averaged output signal;

(d) clamping the averaged output signal to insure that the averaged output signal does not exceed a maximum value, thereby generating a clamped signal; and

(e) using the clamped signal to generate a pulsed signal for triggering the transducer that generates the non-imaging ultrasound waves.

16. The method of claim 13, wherein the non-imaging ultrasound waves comprise at least one of therapeutic ultrasound waves and high intensity focused ultrasound waves.

17. A method for using ultrasound to simultaneously image a target area and apply therapeutic ultrasound waves to a treatment site disposed within said target area, comprising the steps of:

(a) using an ultrasound imaging system to generate an ultrasound image of the target area;

(b) without using the ultrasound imaging system, detecting the scattered ultrasound imaging waves generated by the ultrasound imaging system, producing an output signal that is indicative of the ultrasound imaging waves;

(c) manipulating the output signal to generate a synchronization signal; and

(d) using the synchronization signal to selectively control a transducer that generates the therapeutic ultrasound waves, such that;

(i) the synchronization signal ensures that at least a portion of the ultrasound image is free from interference due to the therapeutic ultrasound waves; and

(ii) a focal point of the therapeutic ultrasound transducer is able to be visualized in the ultrasound image generated by the ultrasound imaging system without being obscured by interference caused by the therapeutic ultrasound waves as they induce a therapeutic effect at the treatment site.

18. The method of claim 17, wherein the step of detecting the scattered ultrasound imaging waves comprises the step of using the therapeutic ultrasound transducer as a receiver to detect the scattered ultrasound imaging waves.

19. The method of claim 17, wherein the therapeutic ultrasound waves comprise high intensity focused ultrasound waves.

20. A system for enabling non-imaging ultrasound to be applied to a target area while simultaneously imaging the target area with an ultrasound imaging system, to enable real-time ultrasound imaging of the target area to be achieved while applying non-imaging ultrasound to the target area, comprising:

(a) a receiver configured to detect scattered ultrasound imaging waves generated by an ultrasound imaging transducer included within the ultrasound imaging system, independently of the ultrasound imaging system, producing an output signal that is indicative of the ultrasound imaging waves; and

(b) a synchronization processor logically coupled to the receiver, the synchronization processor being configured to generate a synchronization signal to be used to control a transducer employed for producing non-imaging ultrasound waves, so that at least a portion of an ultrasound image generated using the ultrasound imaging transducer does not include interference due to the non-imaging ultrasound waves.

21. The system of claim 20, wherein the receiver comprises the transducer that generates the non-imaging ultrasound waves.

22. The system of claim 20, wherein the transducer that generates the non-imaging ultrasound waves comprises a transducer configured to generate high intensity focused ultrasound waves.

23. The system of claim 20, wherein the receiver is configured to be coupled with at least one of an ultrasound imaging probe of the ultrasound imaging system, and a probe that includes the transducer that generates the non-imaging ultrasound waves.

24. The system of claim 20, wherein the synchronization processor is configured to implement the following functions:

(a) detecting the output signal;

(b) determining an envelope of the output signal; and

(c) generating a pulse for triggering the transducer that generates the non-imaging ultrasound waves.

25. The system of claim 20, further comprising a user control switch, wherein the synchronization processor is configured to implement the following functions:

(a) amplifying the output signal;

(b) averaging a plurality of amplitudes defining the output signal to generate an averaged output signal;

(c) amplifying the averaged output signal, to produce an amplified average output signal;

(d) clamping the amplified averaged output signal to insure that the amplified averaged output signal does not exceed a maximum value, thereby generating a clamped signal;

(e) using the clamped signal to generate a pulsed signal for triggering the transducer that generates the non-imaging ultrasound waves; and

(f) combining the pulsed signal for triggering the transducer that generates the non-imaging ultrasound waves with a signal indicative of an active state of the user control switch, to generate the synchronization signal, such that the synchronization signal is used to selectively control the transducer that generates the non-imaging ultrasound waves only when a user has activated the user control switch.

26. The system of claim 20, wherein the synchronization processor comprises at least one of a programmable computing device, an application specific integrated circuit, and a hardware-based synchronization circuit.

27. The system of claim 20, wherein the synchronization processor comprises a hardware-based synchronization circuit that includes:

(a) an amplifier for amplifying the output signal, producing an amplified output signal;

(b) an envelope detector for averaging a plurality of amplitudes of the amplified output signal, to generate an averaged output signal;

(c) an amplifier for amplifying the averaged output signal;

(d) a clamp for clamping the averaged output signal to insure that the averaged output signal does not exceed a maximum value, thereby generating a clamped signal; and

(e) a pulse generator for using the clamped signal to generate a pulsed signal for triggering the transducer that generates the non-imaging ultrasound waves.

28. A synchronization processor configured to enable non-imaging ultrasound waves to be applied to a target area while imaging the target area with an ultrasound imaging system, and to prevent a real-time ultrasound image of the target area from being obscured due to interference caused by the non-imaging ultrasound waves, comprising:

(a) an input configured to be coupled to an output signal from a receiver that is independent of the ultrasound imaging system, but which is configured to detect scattered ultrasound imaging waves generated by an ultrasound imaging transducer that is included within the ultrasound imaging system, the receiver producing the output signal, which is indicative of the ultrasound imaging waves; and

(b) an output configured to be coupled to control activation of a non-imaging transducer, so that the non-imaging transducer is synchronized to produce non-imaging ultrasound waves in regard to production of the ultrasound imaging waves by the ultrasound imaging transducer, so that at least a portion of an ultrasound image generated using the ultrasound imaging transducer does not include interference due to the non-imaging ultrasound waves produced by the non-imaging transducer.

29. The synchronization processor of claim 28, wherein the synchronization processor comprises at least one of a programmable computing device, an application-specific integrated circuit, and a hardware-based synchronization circuit.

30. The synchronization processor of claim 28, wherein the synchronization processor is configured to implement the following functions:

(a) amplifying the output signal, producing an amplified output signal;

(b) averaging a plurality of amplitudes of the amplified output signal to generate an averaged output signal;

(c) amplifying the averaged output signal to produce an amplified averaged output signal;

(d) clamping the amplified averaged output signal to insure that the amplified averaged output signal does not exceed a maximum value, thereby generating a clamped signal; and

(e) using the clamped signal to generate a pulsed signal at the output of the synchronization processor, for triggering the con imaging transducer to produce non-imaging ultrasound waves.

31. The synchronization processor of claim 28, wherein the synchronization processor is further configured to implement the function of combining the pulsed signal for triggering the con imaging transducer with a signal from a user control switch to generate the synchronization signal, such that the synchronization signal is used to selectively control the non-imaging transducer only when a user has activated the user control switch.

32. A therapeutic ultrasound system configured for automatic synchronization with an ultrasound imaging system, to enable real-time ultrasound imaging of a target area to be achieved while applying therapeutic ultrasound to the target area, comprising:

(a) a therapeutic transducer configured to produce therapeutic ultrasound waves;

(b) a receiver configured to detect scattered ultrasound imaging waves generated by an ultrasound imaging transducer included within the ultrasound imaging system, the receiver producing an output signal that is indicative of the ultrasound imaging waves independently of the ultrasound imaging system, and

(c) a synchronization processor logically coupled to the receiver, the synchronization processor being configured to generate a synchronization signal used to control activation of the therapeutic transducer in response to the output signal, so that the therapeutic transducer is synchronized in producing the therapeutic ultrasound waves in regard to activation of the ultrasound imaging transducer, and so that at least a portion of an ultrasound image generated with the ultrasound imaging transducer does not include interference due to therapeutic ultrasound waves produced by the therapeutic transducer.

33. The therapeutic ultrasound system of claim 32, wherein the therapeutic transducer is configured to produce high-intensity focused ultrasound waves.