Laser interaction with vascular tissue: A theoretical and experimental investigation

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5598252

Motamedi, M

Evaluation of the effects of optical scattering albedo ({omega}{sub 0}), anisotropy factor (g), and boundary reflectivities on the light distribution in tissue were based on the rigorous method of discrete ordinate approximation. Optical characteristics of vascular tissue were determined by fitting the measured scattering phase function to an analytical relation to calculate g. Substituting this parameter and the measured total transmission and reflection into an inverse solution to the radiative transfer theory yielded the tissue transport coefficients. Thermodynamic analysis using a finite element solution of the bioheat equation showed a higher subsurface temperature with increased scattering. If both the anisotropic behavior and the optical discontinuities at boundaries are disregarded, significant errors on the calculated temperatures would occur. An in vivo skin model showed that reduced thermal damage to the epidermis and a more uniform coagulation of skin is possible with simultaneous surface cooling during Nd:YAG laser irradiation. In ablation studies, the surface and subsurface temperature rises associated with tissue ablation were monitored during irradiation of normal aortic specimens in air, blood, and saline, at 1.06 {mu}m. Thermal lensing, a non-linear response, was established in egg white. The dependence of tissue response on beam diameter and absorbed energy were studied.

• Research Organization: Texas Univ., Austin, TX (USA)
• OSTI ID: 5598252
• Country of Publication: United States
• Language: English

Related Subjects

560400* -- Other Environmental Pollutant Effects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AORTA
ARTERIES
BIOLOGICAL EFFECTS
BIOLOGICAL MODELS
BLOOD VESSELS
BODY
CARDIOVASCULAR SYSTEM
ELECTROMAGNETIC RADIATION
LASER RADIATION
LASERS
NEODYMIUM LASERS
OPTICAL PROPERTIES
ORGANS
PHYSICAL PROPERTIES
RADIATIONS
SENSITIVITY
SKIN
SOLID STATE LASERS
THERMODYNAMICS