Document Type

Article

Rights

This item is available under a Creative Commons License for non-commercial use only

Disciplines

Medical engineering

Publication Details

International Journal of Mechanical Sciences, Volume 49, Issue 3, March 2007, Pages 298-305. Available from http://www.sciencedirect.com/science?_ob=ArticleListURL&_method=list&_ArticleListID=1086481120&_sort=r&view=c&_acct=C000056897&_version=1&_urlVersion=0&_userid=2322584&md5=4e42746ecf9cfce50fcc05b31e9cffb1

Abstract

Therapeutic ultrasound angioplasty has been investigated, clinically, by a number of researchers and represents a potentially promising therapy for the treatment of atherosclerotic lesions. To date, there has been no detailed analysis of the effect of mechanical design parameters, such as wire geometry or damping characteristics, on wire waveguide performance. An apparatus capable of delivering therapeutic ultrasound down small diameter nickel–titanium (NiTi) wire waveguides is described. The output peak-to-peak (p–p) displacements at the distal tip of a 1.0mm diameter waveguide were measured experimentally, by means of an optical microscope and image analysis software. The output was measured for a range of waveguide lengths from 118 to 303 mm. Wire waveguide distal tip displacements as high as 98 mm (p–p) at 23.5 kHz were measured. For the range of lengths tested, the experimental measurements show the critical relationship between the length of the waveguide and the output distal tip displacements. A finite element model that can predict the resonant frequencies and distal tip displacements of various wire waveguide geometries and configurations, including the effect of damping, is presented. This numerical model has been validated against the experimental displacement data obtained. This will be a valuable design tool for ensuring the safety and effectiveness of therapeutic ultrasound angioplasty procedures.

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