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Proceedings Paper

Spectroscopic feedback in laser lithotripsy and laser angioplasty
Author(s): Zhi Xing Jiang; Terence A. King; T. Shah; Graham M. Watson
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Paper Abstract

The feasibility of new forms of monitoring the fragmentation and ablation process through the plasma feedback signals in laser lithotripsy and laser angioplasty has been investigated. In laser lithotripsy it has been found that shock wave feedback monitoring is not as reliable as the plasma emission feedback monitoring. The plasma emission spectra indicate clearly plasma formation on calculi or calcified plaque, while an audible signal can be observed on targets such as dark tissue, catheter, and blood. This technique was successful in ex-vivo experiments in which calculi were inserted into pigs' ureter and then fragmented. Spectra were obtained in vivo indicating calcium abundance in calculi and the feasibility of real-time stone composition analysis. Ex-vivo gallstone fragmentation was also performed successfully under plasma spectra feedback monitoring. In laser angioplasty, in vitro experiments have shown a discriminative effect at laser pulse energies of 40 mJ or greater. Strong plasma spectra can only be observed from calcified plaque and not from normal artery tissue or fibrous plaque. The threshold for plasma formation on calcified plaque increases in blood compared to that in saline while the spectral structure becomes more specific. This study shows promising prospects for the technique in both laser lithotripsy and laser angioplasty.

Paper Details

Date Published: 1 August 1992
PDF: 10 pages
Proc. SPIE 1649, Optical Fibers in Medicine VII, (1 August 1992); doi: 10.1117/12.60228
Show Author Affiliations
Zhi Xing Jiang, Univ. of Manchester (United Kingdom)
Terence A. King, Univ. of Manchester (United Kingdom)
T. Shah, Institute of Urology (United Kingdom)
Graham M. Watson, Institute of Urology (United Kingdom)


Published in SPIE Proceedings Vol. 1649:
Optical Fibers in Medicine VII
Abraham Katzir, Editor(s)

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