Systems and methods for delivering ultrasound energy at an output power level that remains essentially constant despite variations in transducer impedance

• US 20030050576A1
• Filed: 07/24/2002
• Published: 03/13/2003
• Est. Priority Date: 08/24/2000
• Status: Active Grant

• Current Assignee: TIMI 3 Systems Incorporated
• Original Assignee: TIMI 3 Systems Incorporated
• Inventors: Thompson, Todd A., Suorsa, Veijo T., Horzewski, Michael J.
• Granted Patent: US 7,335,169 B2
• Time in Patent Office: Days
• US Class Current: 601/2
• CPC Class Codes: A61B 2017/00725 Calibration or performance testing
• CPC Class Codes: A61B 2017/00734 battery operated
• CPC Class Codes: A61B 2018/00023 closed, i.e. without wound contact by the fluid
• CPC Class Codes: A61B 90/50 Supports for surgical instruments, e.g. articulated arms
• CPC Class Codes: A61N 2007/0073 using multiple frequencies
• CPC Class Codes: A61N 7/00 Ultrasound therapy lithotripsy A61B17/22, A61B17/225; massage using supersonic vibration A61H23/00 ; using ultrasound for introducing media into the body A61M37/0092

Abstract

Systems and methods deliver ultrasound energy to an ultrasound transducer having an impedance subject to variations. The systems and methods electrically couple an ultrasound generator to the ultrasound transducer to deliver ultrasound energy. The systems and methods deliver ultrasound energy to the ultrasound transducer at a set output frequency and at an output power level that remains essentially constant, despite variations in the impedance, based upon preprogrammed rules.

Claims

1. A system for delivering ultrasound energy to an ultrasound transducer having an impedance subject to variations comprising

an ultrasound generator adapted and configured to be electrically coupled to the ultrasound transducer to deliver ultrasound energy, and

a controller coupled to the generator, the controller being adapted and configured to execute an output power control function that delivers ultrasound energy to the ultrasound transducer at a set output frequency and at an output power level that remains essentially constant, despite variations in the impedance, based upon preprogrammed rules.

2. A system according to claim 1

wherein the controller interrupts delivery of ultrasound energy to the transducer when the impedance is greater than a predetermined maximum level.

3. A system according to claim 1

wherein the controller interrupts delivery of ultrasound energy to the transducer when the impedance is less than a predetermined minimum level.

4. A system according to claim 1

wherein the preprogrammed rules include increasing output voltage in response to an increase in impedance.

5. A system according to claim 4

wherein the preprogrammed rules prevent increasing output voltage to a level greater than a predetermined maximum level.

6. A system according to claim 5

wherein the preprogrammed rules include varying the operating frequency of the ultrasound energy relative to the set operating frequency in response to variations in impedance when the output voltage approaches the predetermined maximum level.

7. A system according to claim 1

wherein the preprogrammed rules include increasing output current in response to a decrease in impedance.

8. A system according to claim 7

wherein the preprogrammed rules prevent increasing output current to a level greater than a predetermined maximum level.

9. A system according to claim 8

wherein the preprogrammed rules include varying the operating frequency of the ultrasound energy relative to the set operating frequency in response to variations in impedance when the output current approaches the predetermined maximum level.

10. A system according to claim 1

wherein the preprogrammed rules include varying the operating frequency of the ultrasound energy relative to the set operating frequency in response to variations in impedance.

11. A system according to claim 1

wherein the controller includes a tuning function that selects the set operating frequency in response to preprogrammed rules.

12. A system according to claim 1

wherein the output power control function delivers ultrasound energy to the ultrasound transducer in pulses.

13. A system according to claim 1

wherein the output power control function delivers ultrasound energy to the ultrasound transducer essentially continuously.

14. A method for delivering ultrasound energy to an ultrasound transducer having an impedance subject to variations comprising the steps of

electrically coupling an ultrasound generator to the ultrasound transducer to deliver ultrasound energy, and

delivering ultrasound energy to the ultrasound transducer at a set output frequency and at an output power level that remains essentially constant, despite variations in the impedance, based upon preprogrammed rules.

15. A method according to claim 14

further including the step of interrupting delivery of ultrasound energy to the transducer when the impedance is greater than a predetermined maximum level.

16. A method according to claim 14

further including the step of interrupting delivery of ultrasound energy to the transducer when the impedance is less than a predetermined minimum level.

17. A method according to claim 14

wherein the preprogrammed rules increase output voltage in response to an increase in impedance.

18. A method according to claim 17

wherein the preprogrammed rules prevent increases in the output voltage to a level greater than a predetermined maximum level.

19. A method according to claim 18

wherein the preprogrammed rules vary the operating frequency of the ultrasound energy relative to the set operating frequency in response to variations in impedance when the output voltage approaches the predetermined maximum level.

20. A method according to claim 14

wherein the preprogrammed rules increase output current in response to a decrease in impedance.

21. A method according to claim 20

wherein the preprogrammed rules prevent increases to the output current to a level greater than a predetermined maximum level.

22. A method according to claim 21

wherein the preprogrammed rules vary the operating frequency of the ultrasound energy relative to the set operating frequency in response to variations in impedance when the output current approaches the predetermined maximum level.

23. A method according to claim 14

wherein the preprogrammed rules vary the operating frequency of the ultrasound energy relative to the set operating frequency in response to variations in impedance.

24. A method according to claim 14

further including the step of selecting the set operating frequency in response to preprogrammed rules.

25. A method according to claim 14

wherein ultrasound energy is delivered to the ultrasound transducer in pulses.

26. A method according to claim 14

wherein ultrasound energy is delivered to the ultrasound transducer essentially continuously.

27. A method according to claim 14

further including the step of locating the transducer to transcutaneously apply the ultrasound energy to a targeted tissue region.