Transmit apodization of an ultrasound transducer array

• US 20050261610A1
• Filed: 05/21/2004
• Published: 11/24/2005
• Est. Priority Date: 05/21/2004
• Status: Active Grant

• Current Assignee: Cilag Gmbh International (Johnson & Johnson)
• Original Assignee: Ethicon Endo-Surgery, Inc. (Johnson & Johnson)
• Inventors: Mast, T. Douglas, Faidi, Waseem, Slayton, Michael H., Barthe, Peter G., Jaeger, Paul M., Leonard, Stephen P.
• Granted Patent: US 7,695,436 B2
• Time in Patent Office: Days
• US Class Current: 601/2
• CPC Class Codes: G01S 7/52047 for elimination of side lobes or of grating lobes; for increasing resolving power
• CPC Class Codes: G10K 11/348 using amplitude variation

Abstract

A system for temporal transmit apodization of an ultrasound transducer array. The system includes a waveform generator and an ultrasound transducer array having a plurality of transducer elements. Each of the transducer elements is driven by a signal generator that generates a periodic waveform. The duty cycle of each signal generator is determined by a predetermined setting of a duty cycle control. The duty cycle of each signal generator is calculated to achieve a desired beam profile of the transducer array, such as acoustic focusing for reducing the level of grating lobes and side lobes. Apodization is achieved by varying the effective amplitude at each array element by varying the duty cycle of the signal provided to each element.

Claims

1. A system for generating a therapeutic ultrasound signal, comprising:

a medical-treatment transducer array having a plurality of transducer elements, each element being adapted to convert a periodic electrical signal to an ultrasound signal; and

a waveform generator coupled to at least one transducer element and including;

at least one signal generator adapted to transmit a periodic electrical signal to the transducer element, and

at least one duty cycle control adapted to control the duty cycle of the periodic electrical signal of an associated signal generator,

wherein at least a plurality of the transducer elements emit ultrasound signals having differing effective amplitudes in accordance with the duty cycle of an associated periodic electrical signal, such that the transducer array emits an apodized therapeutic ultrasound signal.

2. The system of claim 1 wherein:

each transducer element is separately coupled to one of a plurality of signal generators;

each signal generator is coupled to one of a plurality of duty cycle controls; and

each duty cycle control is adapted control the duty cycle of an associated signal generator such that each signal generator generates a predetermined periodic electrical signal.

3. The system of claim 1 wherein the periodic electrical signal is a rectangular waveform.

4. The system of claim 1 wherein the duty cycle of the periodic electrical signal is associated with a plurality of weighted apodization levels derived by dividing the period of the periodic electrical signal into a plurality of equal segments.

5. The system of claim 1 wherein the apodized ultrasound signal is tailored to reduce the level of grating lobes and side lobes.

10. The method of claim 1, further comprising the step of tailoring the apodized ultrasound signal to reduce the level of grating lobes and side lobes.

14. The system of claim 1 wherein the duty cycle of the periodic electrical signal is associated with a plurality of weighted apodization levels derived by dividing the period of the periodic electrical signal into a plurality of equal segments.

15. The system of claim 1 wherein the apodized ultrasound signal is tailored to reduce the level of grating lobes and side lobes.

6. A method for generating a therapeutic ultrasound signal, comprising the steps of:

providing a transducer array having a plurality of transducer elements, each element being adapted to convert a periodic electrical signal to an ultrasound signal; and

coupling to at least one transducer element a waveform generator having;

at least one signal generator adapted to generate and transmit a periodic electrical signal to the transducer element, and

at least one duty cycle control adapted to control the duty cycle of the periodic electrical signal of an associated signal generator,

wherein at least a portion of the transducer elements emit ultrasound signals having differing effective amplitudes in accordance with the duty cycle of an associated periodic electrical signal, such that the transducer array emits an apodized ultrasound signal.

7. The method of claim 6, further comprising the steps of:

separately coupling one of a plurality of signal generators to each transducer element;

separately coupling one of a plurality of duty cycle controls to each signal generator; and

wherein each duty cycle control is adapted control the duty cycle of an associated signal generator such that each signal generator generates a predetermined periodic electrical signal.

8. The method of claim 6, further comprising the step of providing a rectangular periodic electrical signal.

9. The method of claim 6, further comprising the step of associating the duty cycle of the periodic electrical signal with a plurality of weighted apodization levels derived by dividing the period of the periodic electrical signal into a plurality of equal segments.

11. A system for generating a therapeutic ultrasound signal, comprising:

a transducer array having a plurality of transducer elements, each element being adapted to convert a periodic electrical signal to an ultrasound signal; and

a waveform generator coupled to at least one transducer element, including;

a signal generator adapted to generate and transmit a plurality of periodic electrical signals to the transducer elements by means of a plurality of outputs,

a duty cycle control adapted to control the duty cycle of the periodic electrical signals generated by the signal generator, and

a control portion adapted to control at least one of the duty cycle control and the signal generator;

wherein at least a portion of the transducer elements emit ultrasound signals having differing effective amplitudes in accordance with the duty cycle of an associated periodic electrical signal, such that the transducer array emits an apodized therapeutic ultrasound signal.

12. The system of claim 11 wherein the control portion is a digital control.

13. The system of claim 11 wherein the periodic electrical signal is a rectangular waveform.

16. A method for generating a therapeutic ultrasound signal, comprising the steps of:

providing a transducer array having a plurality of transducer elements, each element being adapted to convert a periodic electrical signal to an ultrasound signal; and

coupling to at least one transducer element a waveform generator having;

a signal generator adapted to generate and transmit a periodic electrical signal to the transducer element,

a duty cycle control adapted to control the duty cycle of the periodic electrical signal of an associated signal generator, and

a control portion adapted to control at least one of the duty cycle control and the signal generator;

wherein at least a portion of the transducer elements emit ultrasound signals having differing effective amplitudes in accordance with the duty cycle of an associated periodic electrical signal, such that the transducer array emits an apodized ultrasound signal.

17. The method of claim 16, further comprising the step of providing a digital control.

18. The method of claim 16, further comprising the step of providing a rectangular periodic electrical signal.

19. The method of claim 16, further comprising the step of associating the duty cycle of the periodic electrical signal with a plurality of weighted apodization levels derived by dividing the period of the periodic electrical signal into a plurality of equal segments.

20. The method of claim 16, further comprising the step of tailoring the apodized ultrasound signal to reduce the level of grating lobes and side lobes.