ABSTRACT
Anderson and Parrish (1981) proposed concepts of selective photothermolysis that allowed for specific targeted damage to cells by “suitably brief pulses” of optical radiation based on properties of the target tissue. Anderson (Anderson and Parrish 1983) applied selective photothermolysis to the development of yellow light (585-600 nm) pulsed-dye lasers (PDLs) for treatment of vascular malformations of the skin by targeting oxyhemoglobin. This concept eventually evolved into two angiolytic lasers: the 585 nm PDL and the 532 nm pulsed potassium-titanylphosphate (KTP) laser. These wavelengths are precisely selected to target absorbance peaks of oxyhemoglobin (~571 and ~541 nm) and can fully penetrate intralumenal blood and thereby deposit heat uniformly into the vessel, thereby causing intravascular coagulation and “photoangiolysis” of the subepithelial microcirculation. The short pulse width is precisely selected to contain the heat to the vessel without causing collateral damage to the extravascular soft tissue from heat conduction. The output
of these lasers is transmitted through a thin flexible glass fiber (≤0.6 mm). Therefore, PDL and KTP lasers are well suited for use through the channel of a flexible laryngoscope in the office as well as the speculum of a direct laryngoscope in the operating room. Most recently, a 2 µm continuous wave thulium laser, which retains some of the key cutting and ablative characteristics of the CO2 laser but it is delivered through glass fibers, has been introduced into clinical practice.
