Simultaneous irradiation and imaging of blood vessels during pulsed laser delivery

• Published in: Lasers in surgery and medicine Vol. 24; no. 3; pp. 236 - 243
• Main Authors: Barton, Jennifer Kehlet, Hammer, Daniel X., Pfefer, T. Joshua, Lund, David J., Stuck, Bruce E., Welch, A.J.
• Format: Journal Article
• Language: English
• Published: New York John Wiley & Sons, Inc 1999; Wiley-Liss
• Subjects: Angiography - methods; Animals; Biological and medical sciences; Blood Cells - radiation effects; Blood Flow Velocity - radiation effects; Blood Vessels - radiation effects; confocal microscopy; Cricetinae; Diseases of the cardiovascular system; finite difference model; Lasers; Medical sciences; Mesocricetus; Microscopy, Confocal; Monte Carlo model; port wine stains; pulsed dye laser; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Rhodamines - administration & dosage; Skin - blood supply; Monte Carlo method; Rodentia; Confocal microscopy; Laser irradiation; Modeling; Threshold dose; Vertebrata; Mammalia; Laser pulse; Animal; Blood vessel; Embolization; Medical imagery; Circulatory system; Biological effect; Simultaneity; Hamster; Finite difference method
• ISSN: 0196-8092; 1096-9101
• DOI: 10.1002/(SICI)1096-9101(1999)24:3<236::AID-LSM9>3.0.CO;2-I

Background and Objective Simultaneous irradiation and viewing of 10–120 μm cutaneous blood vessels were performed to investigate the effects of 2‐μs 577‐nm dye laser pulses. Study Design/Materials and Methods A modified scanning laser confocal microscope recorded vessel response to different radiant exposures (J/cm2). Probit analysis determined the 50% probability (“threshold”) radiant exposure necessary to cause embolized or partly occluding coagula, coagula causing complete blood flow stoppage, and hemorrhage. Results A statistically significant difference in the threshold radiant exposure existed for each damage category for blood vessels 10–30 μm in diameter, but not for larger vessels. For vessels over 60 μm, complete flow stoppage was unattainable; increasing laser pulse energy produced hemorrhage. In larger vessels, coagula often were attached to the superficial vessel wall while blood flowed underneath. Monte Carlo optical and finite difference thermal modeling confirmed experimental results. Conclusion These results provide insight into the role of pulse duration and vessel diameter in the outcome of pulsed dye laser irradiation. Lasers Surg. Med. 24:236–243, 1999. © 1999 Wiley‐Liss, Inc.