Pulsed radio frequency electrotherapeutic system

• US 5,584,863 A
• Filed: 07/12/1995
• Issued: 12/17/1996
• Est. Priority Date: 06/24/1993
• Status: Expired due to Term

• Current Assignee: Rio Grande Neurosciences, Inc.
• Original Assignee: Electropharmacology, Inc. (Gemini Health Technologies, Inc.)
• Inventors: Rauch, Thomas, Oh, Se Y., Pilla, Arthur A.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US08/501,290
• Time in Patent Office: 524 Days
• Field of Search: 607/2, 607/71, 607/155
• US Class Current: 607/2
• CPC Class Codes: A61N 1/06 for high-frequency therapy
• CPC Class Codes: A61N 1/40 Applying electric fields by inductive or capacitive coupling microwave apparatus A61N5/00; Applying radio-frequency signals

Abstract

A system for tissue-impedance matched pulsed radio frequency (PRF) electrotherapy includes a power supply, an excitation board for generating PRF signals of a selectable frequency, the board having an input from the power supply. The system also includes a power amplifier for signals from the excitation board. Included is a subsystem for controlling pulse width duration, pulse burst repetition rate, and amplitude of the PRF signals, the controlling system having an input from the power supply. Further provided is a subsystem for continually comparing the amplitude of the PRF signals outputted from the amplifier to a reference value, this including a feedback circuit responsive to difference information between the compared signals and the reference value, the difference information inputted to the controlling subsystem for adjustment of the amplitude and impedance of the PRF signals from the excitation board, the comparing system including an output of power and impedance compensated PRF signals. The system also includes a variable reactance athermapeutic applicator having, as a coaxial cable input, the power and impedance compensated PRF signals outputted from the comparing subassembly, the applicator including a treatment surface having an effective physiologic impedance in the range of 25 to 75 ohms.

Claims

1. A system for tissue-impedance matched pulsed radio frequency (PRF) electrotherapy, the system comprising:

(a) a power supply;

(b) means for generating PRF signals of selected carrier frequency and of a selectable pulse-repetition rate (PPS), said means having an input from said power supply;

(c) means for power amplification of PRF signals from said generating means;

(d) said generating means including means for controlling pulse-width duration, pulse-repetition rate, and amplitude of said PRF signals, said controlling means having an input from said power supply;

(e) comparator means, including a standing-wave-ratio detection circuit (SWR) having a predetermined value of reference-voltage amplitude and phase of an RF signal across an impedance in a range of 25 to 75 ohms, for continually comparing the voltage amplitude and phase of said PRF signals outputted from said amplification means to the reference amplitude value, said SWR circuit producing a ratio signal representative of said comparison, said comparator means including feedback means responsive to said ratio signal for inputting said ratio signal to said controlling means for adjustment of the amplitude and phase of said PRF signals from said generating means, said comparator means providing an output of power and impedance compensated PRF signals; and

(f) a variable reactance athermapeutic applicator having, as its input thereto, the compensated PRF signals outputted from said comparator means, for inducing said compensated PRF signals into tissue to be treated, said applicator comprising first and second spaced parallel capacitor plates;

a magnetic coil wound in a plane parallel to and electrically connected to said capacitor plates;

an RF shield positioned parallel to said coil and on a side of said coil opposite from said capacitor plates; and

control means for varying the space between said capacitor plates.

2. The system as recited in claim 1, in which said applicator comprises:

first and second capacitor plates proximally spaced in substantially parallel relationship thereto;

a magnetic coil wound in a plane parallel to said capacitor plates;

an RF shield positioned parallel to said coil and on a side of said coil opposite from said first and second capacitor plates; and

control means for varying the distance between said first and second capacitor plates.

3. The system as recited in claim 1, in which said applicator further includes a housing for containment of said plates, said coil, said shield and said control means.

4. The system as recited in claim 3, in which said first capacitor plate is movable relative to said housing and in which said second capacitor plate is fixed relative to said housing, and in which said control means comprises a spring plate fixed to said housing, said plate having a screw hole, and a screw mechanism in threaded engagement to said spring plate via the screwhole, and means for selectively operating said screw mechanism to displace said first capacitor plate to vary the space between said plates.

5. The system as recited in claim 3, in which said first capacitor plate is moveable relative to said housing and in which said second capacitor plate is fixed relative thereto.

6. The system as recited in claim 5 including a spring plate attached to said housing in which said first capacitor plate integrally extends from said spring plate.

7. The system as recited in claim 6, further comprising:

a bushing plate affixed to said upper housing plate, said busing plate having a hole therein;

a screw member disposed in said hole and in communication with said first capacitor plate;

control means for controllably turning said screw to change the distance between said first and second capacitor plates.

8. The system as recited in claim 1, in which said RF shield comprises a planar member having an array of electrically grounded linear foil traces thereon.

9. The system as recited in claim 8, in which said planar member comprises a copper wafer.

10. The system as recited in claim 2, in which said comparing means includes phase comparison means between said PRF signal and said reference value therefore.

11. A system for tissue-impedance matched pulsed radio frequency (PRF) electrotherapy, the system comprising:

a) a power supply;

b) means for generating PRF signals of selected carrier frequency and of a selectable pulse repetition rate (PPS), said means having an input from said power supply;

c) means for power amplification of PRF signals from said generating means;

d) said generating means including means for controlling pulse width duration, pulse repetition rate and amplitude of said PRF signals, said controlling means having an input from said power supply;

e) comparator means including a standing wave ratio detection (SWR) circuit having a predetermined value of reference voltage amplitude and phase of an RF signal across an impedance in the range of 25 to 75 ohms, for continually comparing the voltage amplitude and phase of said PRF signals outputted from said amplification means to the reference amplitude value, said SWR circuit producing a ration signal representative of said comparison, said comparator means including feedback means for adjustment of the amplitude and phase of said PRF signals from said generating means, said comparator means providing an output of power and impedance compensated PRF signals; and

f) a variable reactance athermapeutic applicator having, as its input thereto, the compensated PRF signals outputted from said comparator means, for inducing said compensated PRF signals into tissue to be treated.