Tissue treatment system

• US 20060189974A1
• Filed: 02/16/2006
• Published: 08/24/2006
• Est. Priority Date: 02/22/2000
• Status: Active Grant

• Current Assignee: Energist Limited
• Original Assignee: Rhytec Limited
• Inventors: Goble, Nigel M., Penny, Keith, Goble, Colin C.O.
• Granted Patent: US 7,785,322 B2
• Time in Patent Office: Days
• US Class Current: 606/34
• CPC Class Codes: A61B 18/042 using additional gas becoming plasma
• CPC Class Codes: A61B 2017/00725 Calibration or performance testing

Abstract

A tissue treatment system has a radio frequency generator and a handheld treatment instrument that generates a gas plasma jet for delivering thermal energy to a tissue surface to be treated. Incorporated in the housing for the generator is a calibration device for adjusting the energy output of the generator, if necessary, at the beginning of a treatment session. The calibration device has a target element with a target surface, a transducer for sensing changes in temperature of the target element with respect to the temperature of a reference element, and an energy output adjuster for adjusting the radio frequency energy output of the generator in response to a calibration signal generated by the transducer. The generator housing has a receptacle for locating the nozzle of the handheld instrument in juxtaposition with the target element so that when a plasma burst is generated as part of a calibration sequence it is incident on the target surface. The generator output is automatically adjusted to compensate for any deviation of a calibration value, produced from the calibration signal, from a reference value. Also disclosed is a method of regenerating the reticular architecture of tissue, the method including calibrating the energy delivery of a tissue treatment system.

Claims

1. A tissue treatment system including a radio frequency (r.f.) generator, a treatment instrument connectible to the generator and to a source of ionisable gas and operable to produce a plasma jet at a nozzle of the instrument when supplied with the ionisable gas and energised by the generator, and a calibration device which comprises:

a target element having a target surface area,

a transducer arranged to produce an electrical signal indicative of a temperature change of the target element within the target surface area, and

a receptacle for locating the nozzle of the instrument in juxtaposition with the target surface area whereby, in operation of the instrument when in the receptacle, the plasma jet is incident upon the target surface area to cause the transducer to generate a calibration signal for adjusting the energy output of the generator.

2. A system according to claim 1, wherein the calibration device has an output connected to the generator for coupling the calibration signal to the generator, and the generator includes an energy output adjuster for adjusting the r.f. energy output of the generator, the adjuster being configured to adjust the r.f. energy output in response to the calibration signal.

3. A system according to claim 2, wherein the adjuster forms part of a controller which is configured to perform an automatic calibration process in which the generator is operated to feed a predetermined r.f. energy waveform to the instrument to cause generation of a calibration plasma jet directed at the target surface area of the calibration device, the calibration signal generated as a result of the calibration jet heating the target element is processed to produce a calibration value which is then compared with a reference value, and the adjuster is operated automatically in response to a deviation of the calibration value from the reference value to set the r.f. energy output for subsequent operation of the system.

4. A system according to claim 3, wherein the predetermined r.f. energy waveform comprises a plurality of pulses of r.f. energy.

5. A system according to claim 4, wherein the calibration value is a function combining the levels of successive pulses which are generated by the transducer and correspond to the pulses of r.f. energy.

6. A system according to claim 1, wherein the target element is a metallic plate and the transducer is in contact with the plate.

7. A system according to claim 1, wherein the transducer is arranged to produce an electrical signal representative of a difference in temperature between first and second elements of the transducer.

8. A system according to claim 1, wherein the transducer has a measurement surface and a reference surface, which surfaces are spaced apart, and wherein the transducer is operable to produce an electrical signal which is substantially linearly related to the difference between a temperature sensed at the measurement surface and a temperature sensed simultaneously at the reference surface.

9. A system according to claim 1, wherein the target element comprises a first transducer element, wherein the calibration device has a second transducer element spaced from the first transducer element, and wherein the system is arranged to perform a calibration process during which the temperature existing at the first transducer element is compared with the temperature existing at the second transducer element to produce the said electrical signal.

10. A system according to claim 1, wherein the calibration device comprises a calorimeter having a metallic plate forming the target element, a heat sink portion underlying the metallic plate, and a temperature difference sensor located between the metallic plate and the heat sink portion and arranged to produce an electrical output signal indicative of the difference in temperature between the metallic plate and the heat sink portion.

11. A system according to claim 10, wherein the sensor comprises a Peltier device.

12. A system according to claim 6, wherein the transducer has an area greater than the cross-sectional area of the plasma jet when the instrument is operated in its calibration location.

13. A system according to claim 12, wherein the transducer comprises a plurality of temperature sensitive elements distributed in an array.

14. A system according to claim 1, wherein the generator is operable in a calibration mode to cause a burst of r.f. energy to be delivered to the instrument with a predetermined waveform and duration so as to cause the instrument, when supplied with the said gas, to generate a calibration plasma jet, and wherein the calibration device is arranged automatically to evaluate the said electrical signal produced when the calibration plasma jet is incident on the target surface area to generate an adjustment signal for adjusting the energy output of the generator.

15. A system according to claim 14, wherein the calibration device is arranged to evaluate the level of the said electrical signal at a predetermined time after commencement of the burst of r.f. energy.

16. A system according to claim 14, wherein the generator is operable to produce the said burst as a plurality of pulses and the calibration device is arranged to evaluate the level of the said electrical signal after the application of a predetermined number of pulses.

17. A system according to claim 14, wherein the transducer is a temperature difference sensor and the calibration device is arranged to evaluate the level of the said electrical signal when it reaches a maximum level.

18. A system according to claim 14, wherein the generator is operable to produce the said burst as a succession of pulses, the transducer is a temperature difference sensor, and the calibration device is arranged to evaluate the level of the said electrical signal when it reaches a peak level associated with the nth pulse occurring in the said succession of pulses, n being a predetermined integer.

19. A system according to claim 1, wherein:

the generator is contained within a generator housing to which the treatment instrument is coupled by a cable for conveying r.f. energy from the generator to the instrument;

the calibration device is in the generator housing and has an associated instrument holder which opens out on a front section of the housing for receiving the instrument and which is shaped to locate the instrument longitudinally and transversely with respect to the target element.

20. A method of calibrating a tissue treatment system which includes a radio frequency (r.f.) generator, a treatment instrument connected to the generator and to a source of ionisable gas, and a calibration device comprising a target element and a temperature sensing transducer, wherein the method comprises:

placing the treatment instrument in a pre-defined location with respect to the target element;

causing gas to be supplied to the instrument and simultaneously causing a burst of r.f. energy to be delivered to the instrument with a predetermined waveform and duration so as to generate a plasma jet incident upon the target element;

automatically evaluating a calibration signal generated by the calibration device and representative of an output of the transducer resulting from heating of the target element by the plasma jet; and

setting the r.f. energy output level of the generator according to the evaluation of the calibration signal.

21. A calibration device for a gas plasma tissue treatment system, wherein the device comprises:

a target element having a target surface area;

a transducer arranged to produce an electrical signal indicative of a temperature change of the target element; and

a receptacle for locating the nozzle of a handheld gas plasma generating treatment when in the receptacle, the plasma jet is incident upon the target element to cause the transducer to generate a calibration signal indicative of the heating of the target element by the plasma jet.

22. A device according to claim 21, wherein the target element is a metallic plate and the transducer is in contact with the plate.

23. A device according to claim 21, wherein the calibration device comprises a calorimeter having a metallic plate forming a heat sink portion underlying the metallic plate, and a temperature difference sensor, e.g. a Peltier device, located between the metallic plate and the heat sink portion and arranged to produce an electrical output signal indicative of the difference in temperature between the metallic plate and the heat sink portion.

24. A device according to claim 23, wherein the sensor is a Peltier device.

25. A method of regenerating the reticular architecture of tissue using a tissue treatment system having a handheld tissue treatment instrument which emits a thermal energy beam, wherein the method includes calibrating the energy delivery of the system by placing the treatment instrument in registry with a temperature-sensing target device, operating the system to direct a thermal energy beam at the target device, adjusting at least one energy setting of the stem in response to an output of the target device to calibrate the system for energy output, moving the treatment instrument to a treatment position over an area of tissue to be treated, and operating the system to cause thermal energy to be delivered to the tissue surface using the calibrated system.

26. A method of regenerating the reticular architecture of tissue using a source of thermal energy comprising the steps of:

calibrating the source by operating the source in conjunction with a delivered-energy sensing target device and adjusting the source in response to an output of the device, and operating the adjusted source to form first and second regions of thermally modified tissue in a region of the epidermis and the dermis of a patient'"'"'s skin, the first region adjacent to the second region, the first region overlying the second region, and the first region being thermally modified to a greater extent than the second region.

27. A method according to claim 26, wherein operating the adjusted source comprises:

directing the source at a surface of the patient'"'"'s skin to form the first and second regions of thermally-modified tissue, the first region being thermally modified to the extent that the first region separates from the second region a predetermined period after directing the thermal energy at the surface of the patient'"'"'s skin, and a depth of the separation being dependent on an amount of energy directed at the surface of the patient'"'"'s skin and a thermal capacity of the patient'"'"'s skin.

28. A method according to claim 26, wherein operating the thermal energy source comprises:

operating the thermal energy source with a low thermal time constant to form the first and the second regions of thermally-modified tissue in a region of the DE junction.

29. A method according to claim 26, wherein operating the adjusted source comprises:

operating the thermal energy source for a single pass over the patient'"'"'s skin surface; and

setting an energy setting of the thermal energy source dependent on a desired depth of effect.

30. A method according to claim 26, wherein operating the adjusted source comprises:

operating the thermal energy source for at least two passes over the patient'"'"'s skin surface; and

choosing an energy level for each of the at least two passes dependent on the desired depth of the effect.

31. A method according to claim 30, wherein setting the energy setting of the thermal energy source comprises:

setting the energy setting of the thermal energy source in order to create vacuolation on a first pass.

32. A method according to claim 30, wherein setting the energy level of the thermal energy source comprises:

setting the energy setting of the thermal energy source in order to avoid vacuolation on a first pass, and

operating the thermal energy source for at least two passes over the patient'"'"'s skin surface comprises operating the thermal energy source for a second pass without removing treated skin.

33. A method according to claim 26, further comprises:

setting the energy setting of the thermal energy source in order to preserve the integrity of the epidermis as a biological dressing.

34. A method according to claim 26, wherein operating the adjusted source comprises:

operating the thermal energy source so that a line of cleavage occurs within the patient'"'"'s skin two to five days following the operating of the adjusted source, the line of cleavage occurring between the first region and the second region.

35. A method according to claim 34, wherein operating the adjusted source comprises:

operating the energy source in order to form a line of cleavage from two to three cells deep in the stratum corneum of the superficial epidermis and the upper dermis.

36. A method according to claim 34, wherein operating the adjusted source comprises:

operating the thermal energy source such that the tissue in the first region is sloughed tissue.

37. A method according to claim 36, further comprising:

removing the sloughed tissue once a new epidermis has been substantially generated in the region of the line of cleavage.

38. A method according to any of claim 34, wherein tissue below the line of cleavage in the second region includes the lower epidermis, the basal membrane and the DE Junction.

39. A method according to claim 37, wherein at least the basal membrane and the DE Junction are regenerated.

40. A method according to claim 34, wherein operating the adjusted source comprises:

operating the thermal energy source such that the line of cleavage forms below areas of solar elastosis and the solar elastosis and deranged fibroblasts are sloughed.

41. A method according to claim 26, wherein operating the adjusted source comprises:

operating the thermal energy source in order to denature dermal collagen in the second region.

42. A method according to claim 26, wherein operating the adjusted source comprises:

operating the thermal energy source such that tissue in the second region undergoes a regenerative process following regeneration of the epidermis.

43. A method according to claim 42, wherein operating the adjusted source comprises:

operating the thermal energy source such that a reticular architecture of the dermis is at least partially regenerated by fibroblasts less exposed to the effects of UV radiation.

44. A method according to claim 42, wherein operating the thermal energy source comprises:

operating the thermal energy source such that a collagen architecture of the dermis is regenerated at least partially by fibroblasts less exposed to the effects of UV radiation.

45. A method according to claim 42, wherein operating the thermal energy source comprises:

operating the thermal energy source such that an elastin architecture of the dermis is regenerated at least partially by fibroblasts less exposed to the effects of UV radiation.

46. A method according to claim 42, wherein operating the thermal energy source comprises:

operating the thermal energy source such that the GAGS of the dermis is regenerated at least partially by fibroblasts less exposed to the effects of UV radiation.

47. A method according to claim 26, wherein operating the adjusted source comprises:

operating the thermal energy source such that a risk of scarring and hypo pigmentation is substantially eliminated.

48. A method according to claim 26, wherein operating the adjusted source comprises:

operating the thermal energy source such that a progressive improvement in skin changes associated with ageing and photodamage occur over a period of between six and twelve months following the operating of the adjusted source.

49. A method according to claim 26, wherein operating the adjusted source comprises:

operating an instrument having an electrode connected to a power output device;

creating an electric field in the region of the electrode;

generating a plasma by directing a flow of gas through the electric field to, the plasma being generated by virtue of the interaction of the electric field with the gas;

directing the plasma onto the tissue for a predetermined period of time; and

controlling power transferred into the plasma from the electric field so as to desiccate at least a portion of the dermis with vapour pockets formed in dermis cells.

50. A method according to claim 49, further comprising:

operating the power output device to deliver discrete pulses of heat of millisecond duration.

51. A method according to claim 50, wherein operating the power output device comprises:

operating the power output device such that the pulses have a duration between about 0.5 and about 100 milliseconds.

52. A method according to claim 51, wherein operating the power output device comprises:

operating the power output device such that the pulses have a duration between 4.5 and 15.4 milliseconds.

53. A method according to claim 49, further comprising:

operating the power output device to deliver energy between 1 Joule and 4 Joules of energy.