Acoustic manipulation of objects in vivo

Acoustic radiation forces can trap and manipulate objects in three-dimensional space (3D). The state of the art in acoustic trapping has demonstrated the ability to move small or lightweight objects using single or multiple transducers. For certain medical applications, acoustic manipulation can be utilized to control foreign objects in the body, such as kidney stones. However, difficulties from these applications include the ability to control large solid objects, transmitting robust acoustic beams through the skin, and the use of a single source due to limited acoustic window in the body. The goal of this work was to use a 1.5 MHz, focused, multi-element array to synthesize specific acoustic beams to trap, levitate, and steer kidney stone models (glass spheres) in a water bath and urinary bladders of live pigs. Stable acoustic traps were investigated numerically and experimentally in water bath to design a protocol for the 3D manipulation strategies used invivo . Three programmed path were used to levitate and manipulate glass spheres in live pigs. The motion was recorded using a camera and a synchronized ultrasound imaging probe. Deviation from the intended paths was on average <10%. [Work supported by NIH P01-DK043881, K01-DK104854, R01EB7643, and RFBR 20-02-00139.]