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Temperature along the surface of modified fiber tips for Nd:YAG laser angioplasty

Authors :
Frank C. P. Holstege
E. Duco Jansen
Cornelius Borst
Rudolf M. Verdaasdonk
Source :
Lasers in Surgery and Medicine. 11:213-222
Publication Year :
1991
Publisher :
Wiley, 1991.

Abstract

For laser angioplasty probes, the thermal properties of the probes will primarily determine their mechanism of action. We examined the absorption, temperature increase, and probe degradation of transparent contact probes (hemispherical contact probe and ball-shaped fibers) and metal laser probes coupled to a continuous-wave Nd-YAG laser. Temperature was recorded by means of thermocouples and the measurements were corrected for direct light absorption by the thermocouple. During 15 W, 1 s exposure, the peak temperature rise of the hemispherical contact probe in contact with tissue dropped from approximately 1,000 degrees C at the front end to below 45 degrees C (95% drop) at the lateral side. In contrast, during continuous exposure the peak temperature rise of metal laser probes in contact with tissue dropped from 560 degrees C at the front end to near 400 degrees C (30% drop) at the 5.5 mm proximal rear end. During exposure in blood or tissue, the transparent contact probes became contaminated. Their absorption increased from 5 to 33% and the probe deteriorated. Repeated use of metal laser probes in blood resulted in a higher temperature at the rear than at the front end due to backburing of the fiber. Owing to the large temperature drop along the surface of transparent contact probes, the area of thermal destruction is limited to the tissue in front of the probe, whereas along the entire surface of metal laser probes the tissue will be affected. The large difference between these temperature distributions should be respected during clinical application of the transparent contact probe and the metal laser probe.

Details

ISSN :
10969101 and 01968092
Volume :
11
Database :
OpenAIRE
Journal :
Lasers in Surgery and Medicine
Accession number :
edsair.doi.dedup.....98088e28799b17612f8bd6dd6aa5f1eb
Full Text :
https://doi.org/10.1002/lsm.1900110304