Focused ultrasound to displace renal calculi, "Beyond the Abstract," by Michael R. Bailey and Yak-Nam Wang

BERKELEY, CA ( - The clinical application of this research was for the ultrasonic repositioning of kidney stones (see animation). The data presented in this paper were used to obtain an investigational device exemption for this application. The first clinical trial is now nearing completion. To date, no adverse events associated with the treatment have been reported and stones have been moved in nearly all subjects. Many subjects passed small stones immediately following treatment and in several studies, stone movement showed what initially appeared to be one un-passable stone was instead two or more small passable stones. Updates to this research and the clinical trial can be found at

This technology, developed at the University of Washington, is being spun off to a start-up company, Sonomotion, Inc. Despite the technological focus of this paper being the ultrasonic propulsion device, the authors feel that this paper has a much broader utility to helping establish thresholds for safety relevant to many potential ultrasound imaging techniques or therapies. These and other data, for example, have since been used by a sub-committee of the American Institute of Ultrasound in Medicine to publish a summary related to conditionally increased output of the acoustic parameter space where imaging and therapy might be expected to have minimal bio-effect.


Kidney stone being pushed by ultrasound in an in vivo porcine kidney


Written by:
Michael R. Bailey and Yak-Nam Wang as part of Beyond the Abstract on This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.

Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, WA USA

Focused ultrasound to displace renal calculi: Threshold for tissue injury - Abstract

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