Method for mid-intensity, non-ablative acoustic treatment of injured tissue
A method for mid-intensity non-ablative acoustic treatment of injured tissue is disclosed. The method involves continuously moving an ultrasound probe across an extracorporeal skin surface while emitting non-ablative therapeutic ultrasound into the injured tissue in a non-ablative therapeutic ultrasound beam profile. The method terminates energy delivery if movement speed is below a speed threshold. The non-ablative therapeutic ultrasound beam profile provides substantially uniform heating throughout a treatment volume. The heating is non-ablative and triggers a healing response in the injured tissue.
1. A method of treating injured tissue in a human subject, wherein the injured tissue is located within a treatment volume, the treatment volume extending in a depth dimension relative to an extracorporeal skin surface between a proximal boundary depth and a distal boundary depth, wherein the proximal boundary depth is at least 1 mm beneath the extracorporeal skin surface, the method comprising:
a) coupling a handheld ultrasound probe to the extracorporeal skin surface above the injured tissue;
b) continuously moving the handheld ultrasound probe along the extracorporeal skin surface in a movement pattern while the handheld ultrasound probe is emitting a non-ablative therapeutic ultrasound beam profile into the injured tissue, the non-ablative therapeutic ultrasound beam profile having the following characteristics:
a frequency selected to provide substantially uniform heating between the proximal boundary depth and the distal boundary depth in view of selective absorption within the treatment volume and thermal diffusion properties of the treatment volume;
an unfocused, defocused, or weakly focused beam shape, the defocused beam shape having defocusing of between 0° and 45°, wherein the defocusing is measured as an angle relative to a propagation direction of the non-ablative therapeutic ultrasound beam profile, the weakly focused beam shape having an F number of 2 or greater; and
an intensity profile, wherein an average peak intensity is located between the proximal boundary depth and the distal boundary depth, wherein the intensity profile and/or the average peak intensity is adapted to provide a non-ablative thermal profile when the non-ablative therapeutic ultrasound beam profile is active and the handheld ultrasound probe is moving above a speed threshold, wherein continuously applying the non-ablative therapeutic ultrasound beam profile to the treatment volume in an absence of movement and in an absence of a mechanism to terminate the energy delivery would exceed an ablation threshold in at least a portion of the treatment volume;
c) in response to sensing movement speed of the handheld ultrasound probe being below the speed threshold, terminating energy delivery from the ultrasound probe, wherein the continuously moving of step b) defines a lateral cross-sectional shape and lateral cross-sectional size of the treatment volume, wherein the lateral cross-sectional shape is substantially the same as an outline of the movement pattern, wherein the lateral cross-sectional size is between 75% and 125% of a size of the outline of the movement pattern.
2. The method of claim 1 , the method further comprising: d) in response to a second predetermined length of time having lapsed following the terminating of step c) and/or in response to sensing the movement speed of the handheld ultrasound probe being above the speed threshold, re-initiating the emitting of the non-ablative therapeutic ultrasound beam profile from the handheld ultrasound probe.
3. The method of claim 2 , wherein the second predetermined length of time is at least 2 seconds and at most 30 seconds.
4. The method of claim 1 , wherein the intensity profile is substantially consistent over time during use.
5. The method of claim 1 , wherein the emitting of the non-ablative therapeutic ultrasound beam profile of step b) occurs for a length of time between 10 seconds and 20 seconds, followed by terminating the energy delivery from the handheld ultrasound probe.
6. The method of claim 5 , further comprising re-initiating the emitting of the non-ablative therapeutic ultrasound beam profile of step b) and/or repeating steps a) and b).
7. The method of claim 1 , the method comprising repeating steps a) and b) daily over a course of between 2 days and 28 days, thereby providing a therapeutic healing effect.
8. The method of claim 1 , wherein intensity fluctuations throughout the treatment volume are at least ten times greater than temperature fluctuations throughout the treatment volume.
9. The method of claim 1 , wherein the speed threshold is between 0.5 cm/s and 10 cm/s.
10. The method of claim 1 , wherein the ultrasound probe comprises a transmission window that defocuses the ultrasound energy.
11. The method of claim 1 , wherein the ultrasound probe is adapted to provide the non-ablative therapeutic ultrasound beam in pulses having a pulse energy of between 2 J and 10 J.
12. The method of claim 1 , wherein the ultrasound probe is adapted to provide the ultrasound energy in pulses having a pulse power of between 10 W and 100 W.
13. The method of claim 1 , wherein the ultrasound probe is adapted to provide the ultrasound energy in pulses having a pulse duration of between 10 ms and 500 ms, a pulse separation of between 10 ms and 500 ms, or both.
14. The method of claim 1 , the method comprising, applying a coupling medium to the extracorporeal skin surface prior to the coupling of step a).
15. The method of claim 14 , the method further comprising, in response to the continuously moving of step b) occurring for a length of time of between 10 seconds and 15 seconds and/or for a length of time that causes at least a portion of the coupling medium to evaporate, re-applying the coupling medium to the extracorporeal surface and repeating steps a) and b).
16. The method of claim 1 , wherein the method denatures at least a portion of proteins located in the treatment volume.
17. The method of claim 1 , wherein the method establishes a thermal equilibrium in the treatment volume.
18. The method of claim 1 , wherein the continuously moving of step b) includes moving in a coil-shaped pattern.
19. A method of treating injured tissue in a human subject, wherein the injured tissue is located within a treatment volume, the treatment volume extending in a depth dimension relative to an extracorporeal skin surface between a proximal boundary depth and a distal boundary depth, wherein the proximal boundary depth is at least 1 mm beneath the extracorporeal skin surface, the method comprising:
a) coupling a handheld ultrasound probe to the extracorporeal skin surface above the injured tissue;
b) continuously moving the handheld ultrasound probe along the extracorporeal skin surface in a movement pattern while the handheld ultrasound probe is emitting a non-ablative therapeutic ultrasound beam profile into the injured tissue, the non-ablative therapeutic ultrasound beam profile having the following characteristics:
an unfocused, defocused, or weakly focused beam shape, the defocused beam shape having defocusing of between 0° and 45°, wherein the defocusing is measured as an angle relative to a propagation direction of the non-ablative therapeutic ultrasound beam profile, the weakly focused beam shape having an F number of 2 or greater; and
an intensity profile, wherein an average peak intensity is located between the proximal boundary depth and the distal boundary depth, the intensity profile is adapted to deposit energy into tissue in amounts to provide substantially uniform sub-ablative heating within the treatment volume,
c) in response to sensing movement speed of the handheld ultrasound probe being below a speed threshold, terminating energy delivery from the handheld ultrasound probe, wherein the continuously moving of step b) defines a lateral cross-sectional shape and a lateral cross-sectional size of the treatment volume, wherein the lateral cross-sectional shape is substantially the same as an outline of the movement pattern, wherein the lateral cross-sectional size is between 75% and 125% of a size of the outline of the movement pattern.
20. A method of treating injured tissue in a human subject, wherein the injured tissue is located within a treatment volume, the treatment volume extending in a depth dimension relative to an extracorporeal skin surface between a proximal boundary depth and a distal boundary depth, wherein the proximal boundary depth is at least 1 mm beneath the extracorporeal skin surface, the method comprising:
a) coupling a handheld ultrasound probe to the extracorporeal skin surface above the injured tissue;
b) continuously moving the handheld ultrasound probe along the extracorporeal skin surface while the handheld ultrasound probe is emitting a non-ablative therapeutic ultrasound beam profile into the injured tissue, the non-ablative therapeutic ultrasound beam profile having the following characteristics:
an unfocused, defocused, or weakly focused beam shape, the defocused beam shape having defocusing of between 0° and 45°, wherein the defocusing is measured as an angle relative to a propagation direction of the non-ablative therapeutic ultrasound beam profile, the weakly focused beam shape having an F number of 2 or greater; and
an intensity profile, wherein an average peak intensity is located between the proximal boundary depth and the distal boundary depth, the intensity profile adapted to thermally saturate the injured tissue within the treatment volume when the handheld ultrasound probe is moving above a speed threshold,
c) in response to sensing movement speed of the handheld ultrasound probe being below the speed threshold, terminating energy delivery from the handheld ultrasound probe,
wherein the continuously moving of step b) defines a lateral cross-sectional shape and a lateral cross-sectional size of the treatment volume, wherein the lateral cross-sectional shape is substantially the same as an outline of a movement pattern, wherein the lateral cross-sectional size is between 75% and 125% of a size of the outline of the movement pattern.