Improving the lens design and performance of a contemporary electromagnetic shock wave lithotripter.
Abstract
The efficiency of shock wave lithotripsy (SWL), a noninvasive first-line therapy for
millions of nephrolithiasis patients, has not improved substantially in the past two
decades, especially in regard to stone clearance. Here, we report a new acoustic lens
design for a contemporary electromagnetic (EM) shock wave lithotripter, based on recently
acquired knowledge of the key lithotripter field characteristics that correlate with
efficient and safe SWL. The new lens design addresses concomitantly three fundamental
drawbacks in EM lithotripters, namely, narrow focal width, nonidealized pulse profile,
and significant misalignment in acoustic focus and cavitation activities with the
target stone at high output settings. Key design features and performance of the new
lens were evaluated using model calculations and experimental measurements against
the original lens under comparable acoustic pulse energy (E+) of 40 mJ. The -6-dB
focal width of the new lens was enhanced from 7.4 to 11 mm at this energy level, and
peak pressure (41 MPa) and maximum cavitation activity were both realigned to be within
5 mm of the lithotripter focus. Stone comminution produced by the new lens was either
statistically improved or similar to that of the original lens under various in vitro
test conditions and was significantly improved in vivo in a swine model (89% vs. 54%,
P = 0.01), and tissue injury was minimal using a clinical treatment protocol. The
general principle and associated techniques described in this work can be applied
to design improvement of all EM lithotripters.
Type
Journal articleSubject
electromagnetic lithotripterlens modification
stone fragmentation
Animals
Electromagnetic Phenomena
Equipment Design
Female
Lenses
Lithotripsy
Motion
Respiration
Skin
Sus scrofa
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https://hdl.handle.net/10161/8403Published Version (Please cite this version)
10.1073/pnas.1319203111Publication Info
Neisius, Andreas; Smith, Nathan B; Sankin, Georgy; Kuntz, Nicholas John; Madden, John
Francis; Fovargue, Daniel E; ... Zhong, Pei (2014). Improving the lens design and performance of a contemporary electromagnetic shock
wave lithotripter. Proc Natl Acad Sci U S A, 111(13). pp. E1167-E1175. 10.1073/pnas.1319203111. Retrieved from https://hdl.handle.net/10161/8403.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Michael Eric Lipkin
Cary N. Robertson, MD, Associate Professor
John Francis Madden
Associate Professor of Pathology
Glenn Michael Preminger
James F. Glenn, M.D. Distinguished Professor of Urology
1. Minimally invasive management of urologic diseases 2. Minimally invasive management
of renal and ureteral stones 3. Medical management of nephrolithiasis 4. Bioeffects
of shock wave lithotripsy 5. Basic physics of shock wave lithotripsy 6. Intracorporeal
lithotripsy for stone fragmentation 7. Minimally invasive management of urinary tract
obstruction, including ureteropelvic junction obstruction and ureteral strictures
8. Enhanced imaging modalities f
Walter Neal Simmons
Gendell Family Professor of the Practice
Pei Zhong
Professor in the Department of Mechanical Engineering and Materials Science
My research focuses on engineering and technology development with applications in
the non-invasive or minimally invasive treatment of kidney stone disease via shock
wave and laser lithotripsy, high-intensity focused ultrasound (HIFU) and immunotherapy
for cancer treatment, acoustic and optical cavitation, and ultrasound neuromodulation
via sonogenetics.
We are taking an integrated and translational approach that combines fundamental research
with engineering and applied technol
Alphabetical list of authors with Scholars@Duke profiles.

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