Ultrasound "tweezers" are expected to be non-invasible kidney stones

ultrasound beam can remove kidney stones through the body - a method used in pig trials, where a team of researchers was able to move glass beads along a pre-designed route. The findings were published July 6 in the Proceedings of the National Academy of Sciences.
when minerals dissolve in the urine to form crystals, kidney stones are produced, which get stuck in the kidneys or urethra and cause pain.
treatment is to break stones into small pieces, making them easier to excrete with urine. Typically, a slender catheter is pushed from the bladder into the ureter, or ultrasound is emitted from the body, but doing so leaves debris in the body, allowing more stones to grow and, in severe cases, surgery is required.
michael Bailey team at the University of Washington has been looking for a different way to use mild ultrasound to remove stones stuck in the body.
previously, the team tried to give small thrusts to the stones, increasing their chances of natural discharge. They tested for the first time on 15 subjects and showed that small stones moved a little to help them clear from the body.
now, Bailey's team has found a way to better control the movement of stones - using precisely positioned ultrasonic ultrasound around the stones to create high-pressure rings that secure positions. If the high-pressure ring moves, it drags the stones along. "Even if you just move a short distance, it helps." Bailey said.
team tested the method on three anaesthetized pigs, who used glass beads in their bladders instead of kidney stones, which successfully moved at more than 90 percent accuracy over a predetermined line. "It's really manageable." Bailey said.
" is less likely to move irregularly shaped crystals through narrow catheters than to move spline beads in larger spaces such as the bladder. Ben Turney, of the University of Oxford in the UK, says he also believes the technology will help push stones out of places where the kidneys build up easily. (Source: China Science Daily Wenle)
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