Ultrasound based method and apparatus for stone detection and to facilitate clearance thereof
Described herein are methods and apparatus for detecting stones by ultrasound, in which the ultrasound reflections from a stone are preferentially selected and accentuated relative to the ultrasound reflections from blood or tissue. Also described herein are methods and apparatus for applying pushing ultrasound to in vivo stones or other objects, to facilitate the removal of such in vivo objects.
1. A non-lithotriptic method for moving a stone in a living body, comprising displacing the stone by generating a plurality of pulses of ultrasound radiation to push the stone in vivo without fragmenting the stone, the ultrasound radiation imparting a transfer of momentum to the stone resulting in displacement of the stone without causing thermal or mechanical damage to surrounding tissue, wherein the plurality of pulses have a spatial peak temporal average intensity I SPTA in the range of 3 W/cm 2 to 325 W/cm 2 (325 W/cm 2 >I SPTA >3 W/cm 2 ), wherein the plurality of pulses have a pressure amplitude in the range of 5 MPa to 30 MPa.
2. The non-lithotriptic method of claim 1 , wherein the plurality of pulses have a spatial peak temporal average intensity greater than about 4 W/cm 2 (I SPTA > 4 W/cm 2 ).
3. The non-lithotriptic method of claim 1 , wherein the plurality of pulses each have a pulse duration of greater than 2.2 ms.
4. The non-lithotriptic method of claim 1 , wherein the plurality of pulses each have a pulse duration of about 50 ms.
5. The non-lithotriptic method of claim 1 , wherein the stone is exposed to the plurality of pulses for a cumulative time of less than about two minutes.
6. The non-lithotriptic method of claim 5 , wherein the plurality of pulses are generated within a continuous time period of less than about ten minutes.
7. The non-lithotriptic method of claim 1 , wherein the plurality of pulses each includes an ultrasound wave oscillating at a frequency that is greater than or equal to 0.25 MHz and less than or equal to 1 MHz.
8. The non-lithotriptic method of claim 1 , wherein the plurality of pulses each includes an ultrasound wave oscillating at a frequency that is greater than or equal to 1 MHz and less than or equal to 5 MHz.
9. The non-lithotriptic method of claim 1 , wherein the plurality of pulses each includes an ultrasound wave oscillating at a frequency of about 2.3 MHz.
10. The non-lithotriptic method of claim 1 , wherein the plurality of pulses each includes at least 5 oscillation cycles of an ultrasound wave.
11. The non-lithotriptic method of claim 1 , wherein the plurality of pulses each includes at least 10 oscillation cycles of an ultrasound wave.