Non-contact measurement of thermal diffusivity in tissue.
We demonstrate the application of an infrared (IR) imaging technique for non-contact determination of thermal diffusivity in biological materials. The proposed method utilizes pulsed laser excitation to produce an initial three-dimensional temperature distribution in tissue, and records IR images of subsequent heat diffusion. The theoretical model assumes that the time-dependent temperature increase following pulsed laser exposure is due to independent heat diffusion in longitudinal and lateral directions. A nonlinear least-squares algorithm is used to compute the lateral thermal point spread function from a pair of recorded IR images and to determine the thermal diffusivity of a test specimen. The recorded time-sequence of IR images is used to compute thermal diffusivity as a function of increasing time interval between two IR emission images. Experimental application of the method was demonstrated using tissue phantoms, ex vivo samples of hydrated cartilage and in vivo epidermis.
Biomedical Engineering Program, University of Texas at Austin, 78712, USA.
S A
SA
Telenkov
J I
JI
Youn
D M
DM
Goodman
A J
AJ
Welch
T E
TE
Milner
D000328:Adult; D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D001831:Body Temperature / Q000528:radiation effects*; D004058:Diffusion; D004817:Epidermis / Q000528:radiation effects; D006801:Humans; D066298:In Vitro Techniques; D007259:Infrared Rays; D053685:Laser Therapy; D019047:Phantoms, Imaging; D013552:Swine