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Temperature along the surface of modified fiber tips for Nd:YAG laser angioplasty
Author(s) -
Verdaasdonk Rudolf M.,
Holstege Frank C.,
Jansen E. Duco,
Borst Cornelius
Publication year - 1991
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/lsm.1900110304
Subject(s) - thermocouple , laser , materials science , drop (telecommunication) , optics , temperature measurement , absorption (acoustics) , composite material , telecommunications , physics , quantum mechanics , computer science
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°C at the front end to below 45°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°C at the front end to near 400°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 transparant contact probe and the metal laser probe.