Broad-area irradiation of small near-field targets using ultrasound

• US 8,585,618 B2
• Filed: 12/18/2009
• Issued: 11/19/2013
• Est. Priority Date: 12/22/2008
• Status: Active Grant

• Current Assignee: Cutera Incorporated
• Original Assignee: Cutera Incorporated
• Inventors: May, Justin, Smith, Tonee, Hunziker, Lukas
• Primary Examiner(s): Jung, Unsu
• Assistant Examiner(s): SIRIPURAPU, RAJEEV P
• Application Number:
  US12/642,686
• Publication Number:
  US 20100160837A1
• Time in Patent Office: 1,432 Days
• Field of Search: 601/2, 601/3
• US Class Current: 601/2
• CPC Class Codes: A61B 2017/00752 Hair removal or transplantation
• CPC Class Codes: A61B 2018/00005 Cooling or heating of the probe or tissue immediately surrounding the probe
• CPC Class Codes: A61N 2007/0056 Beam shaping elements
• 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

An ultrasonic transducer system for treating a portion of tissue. The ultrasonic transducer system includes a frequency generator, an ultrasonic transducer, and a transmitter element. The transducer receives an AC voltage from the frequency generator and produces an ultrasonic energy pulse at an ultrasonic frequency for a pulse width. The transmitter element is coupled to the transducer and is for irradiating a portion of skin tissue. The transmitter element has a chilled surface in contact with the skin tissue and an acoustic aperture for producing a substantially collimated energy beam. The beam has a width greater than 4 mm.

Claims

1. A method of inhibiting hair growth in a skin tissue, the method comprising:

placing a unitary ultrasonic transducer in contact with the skin tissue, the transducer having an acoustic aperture for producing a substantially collimated energy beam over a treatment area greater than 16 mm², wherein the substantially collimated energy beam is produced by a single transducer element, wherein the cross-sectional area of the substantially collimated energy beam does not vary by more than 20% over a distance of at least 5 mm from the surface of the skin tissue to a treatment plane, and wherein a chilled surface is in contact with the skin tissue, the tissue having a plurality of hair follicles within the treatment area; and

generating a plurality of ultrasonic energy pulses, by supplying a drive frequency to the transducer, said pulses for heating the hair follicles, said pulses being generated with at least two different drive frequencies selected to reduce variations in the intensity profile across the treatment area.

2. The method of claim 1, wherein a combined pulse widths of all of the energy pulses total less than 100 ms.

3. The method if claim 1, wherein the intensity of the ultrasonic energy pulse at the transducer is greater than 150 W/cm2.

4. The method of claim 1, wherein the frequency of the ultrasonic energy pulses are between 5 and 20 MHz.

5. A method as recited in claim 1 wherein the variation between the two drive frequencies is at least 0.25% of the average drive frequency.

6. A method as recited in claim 1 wherein the variation between the two drive frequencies is at least 1.0% of the average drive frequency.

7. A method of inhibiting hair growth in a skin tissue, the method comprising:

placing a unitary ultrasonic transducer in contact with the skin tissue, the skin tissue including a plurality of hair follicles, the transducer having a surface area greater than 1 cm² in contact with the skin tissue;

generating a plurality of ultrasonic energy pulses, by driving the transducer with a drive frequency, said pulses for heating the hair follicles with a substantially collimated beam, wherein the substantially collimated beam is produced by a single transducer element of the unitary ultrasonic transducer, and wherein the cross-sectional area of the substantially collimated energy beam does not vary by more than 20% over a distance of at least 5 mm from the surface of the skin tissue to a treatment plane; and

varying the drive frequency of the pulses to reduce variations in the intensity profile across the treatment area.

8. A method as recited in claim 7 wherein the difference between the highest drive frequency and the lowest drive frequency is at least 0.25% of the average drive frequency.

9. A method as recited in claim 7 wherein the difference between the highest drive frequency and the lowest drive frequency is at least 1.0% of the average drive frequency.