RF device for tissue treatment

Abstract

An applicator includes at least one RF electrode coupled to an RF generator. The at least one RF electrode has protrusions each with a curvature radius which is equal to or greater than a curvature radius of an outer edge of the at least one RF electrode.

Claims

1. A device for non-ablative thermal treatment of tissue comprising: an RF (radio frequency) generator; and an applicator comprising at least one RF electrode coupled to said RF generator, wherein said at least one RF electrode comprises an array of spaced-apart protrusions located on a distal face of said at least one RF electrode, said protrusions extending between inner and outer portions of said at least one RF electrode, and each of said protrusions having a curved distal tip being defined by a radius of curvature and an amount of protrusion from said distal face, and wherein said radii of curvature or said amounts of protrusion vary between said inner and said outer portions of said at least one RF electrode.

2. The device according to claim 1, further comprising a tissue temperature sensor coupled to said applicator.

3. The device according to claim 2, wherein RF energy is adjusted according to tissue temperature monitored by said tissue temperature sensor.

4. The device according to claim 1, wherein said at least one RF electrode has a contact area larger than 6 mm.sup.2.

5. The device according to claim 1, wherein some of said radii of curvature or said amounts of protrusion increase from said inner to said outer portions of said at least one RF electrode.

6. The device according to claim 1, wherein some of said radii of curvature or said amounts of protrusion decrease from said inner to said outer portions of said at least one RF electrode.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the accompanying drawings:

(2) FIG. 1 is a schematic representation of the hand piece applied for treatment of peri-orbital wrinkles.

(3) FIG. 2 is a schematic representation of the RF current distribution between two smooth electrodes.

(4) FIG. 3 is a schematic representation of the hand piece with RF two electrodes having protrusions.

(5) FIG. 4 is a schematic representation of the RF current distribution between two electrodes with protrusions.

(6) FIG. 5 is a schematic representation of the RF current distribution at mono-polar electrode with protrusions.

DETAILED DESCRIPTION

(7) Referring first to FIG. 1, a device 12 is applied to the lower eyelid 11 for treatment of peri-orbital wrinkles. Alternatively other areas outside of the face or body can be treated. The device can be used for treatment inside the natural openings.

(8) FIG. 2 shows the distribution of RF current 24 between two electrodes 22 and 23 connected to hand piece 21. RF current 24 has a higher density near the inner edges of the electrodes 22, 23 creating hot spots 25, 26. These hot spots can result in thermal damage of the tissue.

(9) FIG. 3 shows hand piece 31 according to an embodiment of the invention with two electrodes 32, 33 applied to the treated tissue. Each electrode has an internal edge 37 and protrusions 34, 35, and 36.

(10) FIG. 4 shows hand piece 31 according to an embodiment of the invention with two electrodes 32, 33 applied to the treated tissue. Each electrode has protrusions 34, 35, and 36. The RF current 41 concentrated on protrusions in the same way as on the inner edge of electrodes, creating a more uniform RF current distribution over the electrode area in comparison with smooth electrodes shown in FIG. 2.

(11) FIG. 5 shows mono-polar hand piece 51 according to an embodiment of the invention with single electrodes 52 applied to the treated tissue. Each electrode has an inner edge 53 and protrusions 54, 55, 56, and 57.

(12) The hand piece is connected to the RF generator generating electrical current with a frequency, without limitation, of 400 kHz to 6 MHz. Electrodes 52 have an embedded thermal sensor monitoring skin temperature during the treatment.

(13) FIG. 5 shows the hand piece surface with two electrodes 52. The electrode has edge 53 and protrusions 54-57. The protrusions amplify RF current density 59 in the inner part of electrode to make it virtually equal to the current density 58 at the edge of electrode.

(14) The treatment with the RF device having electrodes according to the invention, without limitation, has the following steps: Applying layer of conductive gel which thick enough to fill volume in between protrusions Applying hand piece to the treated tissue with firm pressure to ensure good contact between skin and electrodes. Move hand piece over the treatment area to reach and maintain skin temperature in the range of 40° C. to 50° C. RF energy is terminated when skin temperature reaches the pre-set level and turned on automatically when measured temperature is below the pre-set level.

(15) The preferred parameters for device, without limitation, are the following:

(16) 1. RF peak voltage applied to the tissue in the range of 10V to 1000V

(17) 2. Average RF power from 1 W to 50 W

(18) 3. RF frequency in the range of 400 kHz to 6 MHz

(19) 4. Tissue contacting area of hand piece is 0.1 cm.sup.2 to 6 cm.sup.2

(20) 5. Temperature sensor embedded into the one or more electrodes controls maximal tissue heating in the range of 40° C. to 50° C. according to user setting.

(21) 6. RF energy as controlled according to feedback from temperature sensor and impedance measurements. If measured parameters are out of accepted range, the RF energy is terminated.