13 June 2000 Laser-tissue photothermal interaction and tissue temperature change
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Proceedings Volume 3914, Laser-Tissue Interaction XI: Photochemical, Photothermal, and Photomechanical; (2000) https://doi.org/10.1117/12.388026
Event: BiOS 2000 The International Symposium on Biomedical Optics, 2000, San Jose, CA, United States
Responses of tissue to laser stimulation are crucial in both disease diagnostics and treatment. In general, when tissue absorbs laser energy photothermal interaction occurs. The most important signature of the photothermal reaction is the tissue temperature change during and after the laser irradiation. Experimentally, the tissue reaction to laser irradiation can be measured by numerous methods including direct temperature measurement and measurement of perfusion change. In this study, a multiple-channel temperature probe was used to measure tissue temperature change during irradiation of lasers with different wavelengths at different power settings. Tissue temperature in chicken breast tissue as well as skin and breast tumor of rats was measured during irradiation of an 805-nm diode laser. The vertical profiles of temperature were obtained using simultaneous measurement at several different locations. The absorption of laser energy by tissue was enhanced by injecting laser-absorbing dye into the tissue. A Nd:YAG laser of 1064-nm wavelength was also used to irradiate turkey breast tissue. Our results showed that both laser penetration ability and photothermal reaction depended on the wavelength of lasers. In the case of 805-nm laser, the temperature increased rapidly only in the region close to the laser source and the thermal equilibrium could be reached within a short time period. The laser absorbing dye drastically enhanced the thermal reaction, resulting in approximately 4-fold temperature increase. On the contrary, the laser beam with 1064-nm wavelength penetrated deeply into tissue and the tissue temperature continued increasing even after a 10-minute laser irradiation.
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Andrea K. Ives, Andrea K. Ives, Wei R. Chen, Wei R. Chen, Baha Jassemnejad, Baha Jassemnejad, Kenneth Eugene Bartels, Kenneth Eugene Bartels, Hong Liu, Hong Liu, John A. Nordquist, John A. Nordquist, Robert E. Nordquist, Robert E. Nordquist, "Laser-tissue photothermal interaction and tissue temperature change", Proc. SPIE 3914, Laser-Tissue Interaction XI: Photochemical, Photothermal, and Photomechanical, (13 June 2000); doi: 10.1117/12.388026; https://doi.org/10.1117/12.388026

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