17 September 1999 Photothermal effect for arteriosclerotic region using infrared free electron lasers
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Proceedings Volume 3863, 1999 International Conference on Biomedical Optics; (1999) https://doi.org/10.1117/12.364423
Event: International Symposium on Biomedical Optics, 1999, Wuhan, China
Cholesteryl oleate can be selectively removed with an infrared free-electron laser (IFEL). To determine the mechanisms that are involved in the effects induced by IFEL, we compared the effect of FEL exposure and the effect of heating on a sample film and bulk sample of cholesteryl oleate. Heating is regarded as one of the mechanisms by which FEL ablates cholesteryl oleate that has accumulated on the arteriosclerotic region of arterial walls. FEL was applied at a wavelength of 5.75 micrometers and at several average powers (2 - 15 mW). FEL exposure induced melting and a decrease in the number of ester bonds. Using the value of absorbed IFEL- macropulse energy for each power density, the temperature was assumed to be 50 - 300 degree(s)C. In the heating experiment, the sample was heated from room temperature to 500 degree(s)C. Melting and carbonization were observed at 50 degree(s)C and 300 degree(s)C, respectively. We found that FEL exposure and heating each induced melting. FEL exposure induced chemical changes and ablation of cholesteryl oleate, although heating did not. Heating the cholesteryl oleate above 305 degree(s)C induced carbonization, although FEL exposure to the same temperature did not.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Kunio Awazu, Kunio Awazu, Yuko Fukami, Yuko Fukami, } "Photothermal effect for arteriosclerotic region using infrared free electron lasers", Proc. SPIE 3863, 1999 International Conference on Biomedical Optics, (17 September 1999); doi: 10.1117/12.364423; https://doi.org/10.1117/12.364423

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