FEL experiments to study the effect pulse duration on the biological consequences of laser-induced stress waves

The therapeutic applications of laser-induced stress waves have been limited to the disruption of noncellular material such as renal stones, atheromatous plaque, vitreous strands and other ocular membranes. Recent experiments at the Wellman Laboratories of Photomedicine have demonstrated that there is also potential therapeutic applications of laser-induced stress waves for cellular processes. It has been established that stress waves can lead to selective killing of the cell cultures. The present studies are designed to investigate in a coherent way the parameters of the stress waves that can most efficiently cause cell death. This work coupled with the characterization of laser-induced pressure waves determine whether the scheme of selective killing of cells meditated by stress waves is a valid concept as a treatment. Laser-induced stress wave generation has unique properties when compared to other methods of generating pressure transients, particularly, ultrasound. These properties allow for the isolation of stress waves some of the other physical phenomena that occur during ultrasound and which frequently overwhelm the more subtle and potentially useful effects of the pressure transients. In combination with drugs, the laser-induced stress waves may offer a unique treatment regimen.