Thursday, January 29, 2009, Condensed Matter Biological Physics Seminar, Glenn Edwards, Physics Dept., Duke University, "Surgery with Pulsed, Infrared Lasers: Applications, Mechanisms, and Technology", 4:30 PM, Doherty Hall A310, CMU
 

Abstract:

The mid-infrared Mark-III Free-Electron Laser (FEL) can ablate (“cold-etch”) tissue (1) and has been used successfully in human neurosurgery and ophthalmic surgery (2).  The physical mechanism for infrared tissue ablation and how certain mechanistic features correlate with the preferential ablative properties is partially understood (3,4).  While it has been known for some time that the dynamics of tissue ablation include (laser-driven) vibrational dynamics leading to superheating tissue water on the nanosecond time scale, only recently have experiments led us to understand that the overall mechanism also includes FEL-driven vapor bubble dynamics as confined by tissue matrix with remarkable and unexpected wavelength dependence (5,6).  In addition, I will review progress to develop alternative laser technology to the Mark-III FEL for human surgery that is relatively compact and inexpensive (7).

1.  "Tissue Ablation by a Free-Electron Laser Tuned to the Amide II Band," Nature 371, 416-419 (1994).

2.  “FEL-based-biophysical and biomedical instrumentation,” Review of Scientific Instruments 74(7), 3207-3245 (2003).

3.  “Thermal Diffusion and Chemical Kinetics in Laminar Biomaterial Due to Heating by a Free-Electron Laser,” Physical Review E 65: 061906 (2002).

4.  “Applications of Free-Electron Lasers in the Biological and Material Sciences,” Photochemistry and Photobiology 81, 711-735 (2005).

5.  “Pressure (mechanical) effects in infrared tissue ablation,” Proceedings of SPIE 6854, 685410 (2008).

6.  “Thermal Vapor Bubble and Pressure Dynamics During Infrared Laser Ablation of Tissue,” (submitted).

7.  “6450-nm Wavelength Tissue Ablation Using a Nanosecond Laser Based on Difference Frequency Mixing and Stimulated Raman Scattering,” Optics Letters 32, 1426-1428 (2007).