Laser pulse duration must match the estimated thermal relaxation time for successful photothermolysis of blood vessels
- 349 Downloads
The relationship between photothermal damage to blood vessels of diameter,d, and laser pulse duration,tp, was verified in a series of studies using the chick chorioallantoic membrane (CAM). A total of 879 individual CAM blood vessels (d=50–130μm) was irradiated, using a laser pulse duration of 0.45 or 10 ms. Laser-induced vascular damage was observed in real time, recorded on videotape, and evaluated in a double-blind fashion. Permanent damage was confirmed by inspection 24 h after laser exposure. Under the conditions of this experiment, only when laser pulse durations are approximately equal to the estimated thermal relaxation times (τ) of the CAM microvessels can the critical core intravascular temperature, necessary to destroy vessels irreversibly, be achieved and sustained for sufficient time. Shorter pulse durations are more effective for damaging smaller blood vessels; conversely, longer pulse durations are more effective for damaging larger diameter vessels.
Key wordsBlood vessel Laser Photothermolysis Port-wine stain Thermal relaxation time
Unable to display preview. Download preview PDF.
- 4.Fuchs A, Lindenbaum ES. The two- and three-dimensional structure of the microcirculation of the chick chorioallantoic membrane.Acta Anat 1988,13:271–5Google Scholar
- 7.Gradshteyn IS, Ryzhik IM. In: Jeffrey A (ed)Table of Integrals, Series and Products, 4th edn. San Diego: Academic Press, 1980Google Scholar
- 8.Mathematical tables projects: table of Struve functions Lv(x) and Hv(x).J Math Phys 1946, 25:252–9Google Scholar
- 9.van Gemert MJC, Welch AJ, Miller ID, Tan OT. Can physical modeling lead to an optimal laser treatment strategy for port-wine stains? In: Wolbarsht ML (ed)Laser Applications in Medicine and Biology, Vol. 5. New York: Plenum Press, 1991: 199–275Google Scholar
- 13.Jacques SL, Nelson JS, Wright WH, Milner TE. Pulsed photothermal radiometry of port-wine-stain lesions.Appl Optics 1993,32:2439–46Google Scholar