OPERATION OF PATTERNED ULTRASONIC TRANSDUCERS

• US 20110251527A1
• Filed: 06/22/2011
• Published: 10/13/2011
• Est. Priority Date: 03/13/2008
• Status: Abandoned Application

• Current Assignee: Ultrashape Ltd.
• Original Assignee: Ultrashape Ltd.
• Inventors: Kushculey, Leonid, Goland, Vladimir
• Application Number:
  US13/166,474
• Publication Number:
  US 20110251527A1
• Time in Patent Office: Days
• US Class Current: 601/2
• CPC Class Codes: A61B 8/4494 characterised by the arrangement of the transducer elements devices for short-range imaging using particular transducer elements arrangements under G01S15/8909; arrangements of transducers in generation of mechanical vibrations of infrasonic, sonic or ultrasonic frequency B06B1/0607
• CPC Class Codes: A61N 2007/0008 Destruction of fat cells
• CPC Class Codes: A61N 2007/0065 Concave transducers
• CPC Class Codes: A61N 2007/0078 with multiple treatment transducers
• CPC Class Codes: A61N 2007/0095 by modifying an excitation signal
• CPC Class Codes: A61N 7/02 Localised ultrasound hyperthermia hyperthermia in general A61F7/00
• CPC Class Codes: B06B 1/0637 Spherical array

Abstract

A method for lysing fat cells using a multi-element, phased array piezoelectric transducer, the method comprising: providing a multi-element, phased array piezoelectric transducer comprising a single unitary piece of piezoelectric material having a plurality of electrode elements being formed as a segmented conductive layer on at least one surface of the piezoelectric material, each segment of the conductive layer being associated with an individual transducer element; positioning the transducer over a body of a patient, in proximity to a target volume containing fat cells; causing at least some of the transducer elements to emit ultrasound energy by exciting their associated electrode elements with high frequency voltages, the ultrasound energy having a power density at the target volume which is higher than a cavitation threshold; and spatially steering the ultrasound energy across the target volume by controlling the excitation of electrode elements in the time domain, thereby inducing cavitation in fat cells contained in the target volume.

Claims

1. A method for lysing fat cells using a multi-element, phased array piezoelectric transducer, the method comprising:

providing a multi-element, phased array piezoelectric transducer comprising a single unitary piece of piezoelectric material having a plurality of electrode elements being formed as a segmented conductive layer on at least one surface of the piezoelectric material, each segment of the conductive layer being associated with an individual transducer element;

positioning the transducer over a body of a patient, in proximity to a target volume containing fat cells;

causing at least some of the transducer elements to emit ultrasound energy by exciting their associated electrode elements with high frequency voltages, the ultrasound energy having a power density at the target volume which is higher than a cavitation threshold; and

spatially steering the ultrasound energy across the target volume by controlling the excitation of electrode elements in the time domain, thereby inducing cavitation in fat cells contained in the target volume.

2. The method according to claim 1, wherein the single unitary piece of piezoelectric material is spherical, thereby allowing for an enhanced pressure gain (K_P), wherein the pressure gain is defined as a ratio of pressure (P_F) in a focal zone of the transducer to pressure (P_S) on a surface of the transducer.

3. The method according to claim 1, wherein the causing of the at least some of the transducer elements to emit ultrasound energy comprises:

causing a first group of the transducer elements to emit ultrasound energy producing a first ovoid focal volume inside the target volume; and

causing a second group of the transducer elements to emit ultrasound energy producing a second ovoid focal volume inside the target volume,

wherein the first and second ovoid focal volumes are partially overlapping and differently aligned, such that a combined power density where the first and second ovoid focal volumes overlap is above the cavitation threshold.

4. The method according to claim 3, wherein the causing of the first and second groups to emit ultrasound energy is performed simultaneously.

5. The method according to claim 3, wherein the causing of the first and second groups to emit ultrasound energy is performed closely sequentially.

6. The method according to claim 3, wherein the cavitation induced in the fat cells contained in the target volume provides selective fat cell lysis, wherein lysis of non-fat tissue contained in the same target volume and receiving the ultrasound energy is prevented.

7. The method according to claim 6, wherein, in order to provide the selective fat cell lysis, the power density at the target volume is provided at an I_SPPA (Intensity, Spatial Peak, Pulse Average) value of

8. The method according to claim 7, wherein MI is between approximately 8-10.

9. The method according to claim 7, wherein, further in order to provide the selective fat cell lysis, a duty cycle at which the electrode elements are excited is between approximately 3.6% and 6.7%.

10. The method according to claim 1, wherein:

at least some of the transducer elements are regions of different thicknesses in the single unitary piece of piezoelectric material; and

the causing of the at least some of the transducer elements to emit ultrasound energy further comprises exciting regions of different thicknesses, thereby causing ultrasound energy of different frequencies, respectively, to be emitted.

11. The method according to claim 10, further comprising manipulating a focal size of the ultrasound energy by controlling the emission of ultrasound energy of different frequencies.

12. The method according to claim 10, wherein the causing of the at least some of the transducer elements to emit ultrasound energy further comprises:

causing a first group of the transducer elements which have a common thickness to emit ultrasound energy of a first frequency, producing a first ovoid focal volume inside the target volume; and

causing a second group of the transducer elements which have a different common thickness to emit ultrasound energy of a second frequency, producing a second ovoid focal volume inside the target volume,

wherein the first and second ovoid focal volumes are positioned one inside the other and differently aligned, such that a combined power density where the first and second ovoid focal volumes overlap is above the cavitation threshold.

13. The method according to claim 12, wherein the causing of the first and second groups to emit ultrasound energy is performed simultaneously.

14. The method according to claim 12, wherein the causing of the first and second groups to emit ultrasound energy is performed closely sequentially.

15. The method according to claim 10, further comprising optimizing a spatial intensity profile of the ultrasound energy by controlling the emission of ultrasound energy of different frequencies.

16. The method according to claim 15, wherein the optimization of the spatial intensity profile comprises maximizing power concentration at a main lobe of the profile while minimizing power concentration at side lobes of the profile.

17. The method according to claim 15, further comprising limiting the maximization of the power concentration at the main lobe to an estimated pain threshold of the patient.