We have developed an opto-thermal model for the interaction of laser light and the tissue of arterial walls, and have checked its validity with animal experiments. The mathematical model consists of a laser diffusing tip positioned intraluminally in a cylindrical artery, in which the diffused laser light is incident on a blood/tissue interface at a distance from the tip. Experimental values for the optical scattering, absorption, transmission, and reflection in biological media are taken from the literature. A temperature profile throughout the interface is obtained by considering the optical interaction and the thermal conduction and convection of the blood and tissue. For experimental verification, a diffusing tip was inserted in in vivo canine arteries and the temperature profile was measured by a thermocouple array. The rate of blood flow around the diffusing tip was varied by limiting the volume of blood; this simulated degrees of occlusion to determine the influence of blood flow on heat transport. The measured temperature profile compared favorably to the theoretical results. The theoretical model will be useful in predicting the depth of tissue ablation and extent of normal tissue damage for laser angioplasty treatment of atherosclerosis.

Date Published: 3 June 1988
PDF: 8 pages
Proc. SPIE 0908, Laser Interaction with Tissue, (3 June 1988); doi: 10.1117/12.945340

Published in SPIE Proceedings Vol. 0908:
Laser Interaction with Tissue
Michael W. Berns, Editor(s)