Related Experiment Videos
New approaches to the treatment of vascular lesions
1Cosmetic Surgery and Laser Center, Department of Dermatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
Background And Objective:
The pulsed dye laser was developed based on the concept of selective photothermolysis. By using a wavelength of light well absorbed by the target and pulse duration short enough to spatially confine thermal injury, specific vascular injury could be produced.
Study Design/Materials And Methods:
Although the pulsed dye laser revolutionized the treatment of port wine stains (PWS) and a variety of other vascular lesions, the ideal thermal relaxation time for the vessels in PWS is actually 1-10 ms, not 450 micros of the original pulsed dye laser machines. These original theoretical calculations recently have been proven correct in a study that used both an animal vessel model and in human PWS.
Results:
Longer wavelengths of light, within the visible spectrum, penetrate more deeply into the skin and are more suitable for deeper vessels, whereas longer pulse durations are required for larger caliber vessels.
Conclusion:
A variety of lasers recently have been developed for the treatment of vascular lesions which incorporate these concepts into their design, including pulsed dye lasers at 1.5 ms, a filtered flash-lamp pulsed light source with pulse durations of 1-20 ms, several 532-nm pulsed lasers with pulse durations of 1 ms to as high as 100 ms, long pulsed alexandrite lasers at 755 nm with pulse durations up to 20 ms, pulsed diode lasers in the 800 to 900 nm range, and long pulsed 1064 Nd:YAG sources.