Why is the 970nm (980nm class) wavelength important?

 

Diode lasers have different effects on tissue depending on the wavelength and absorption levels

Absorption is dependent on:

    1. Water content of tissue
      • Because soft tissue contains a high percentage of water (around 70%), a surgical laser must be well absorbed in water to ablate tissue properly
      • The better water absorbs light the better it cuts!!
    2. Tissue composition (other than water):
      • Hemoglobin
        • Absorption in hemoglobin is imperative for char-free coagulation and successful hemostasis
      • Melanin
    3. Laser light
      • 970nm cuts optically not thermally, using the laser light
      • Cuts by vaporizing water independently of other tissue composition

 

A laser´s wavelength determines many of its properties and capabilities because different wavelengths are absorbed by tissue at varying rates

Tissue

Water Absorption The Absorption of Light Energy in Water is:

3%

15%

35%

for 810nm

for 1064nm

for 980nm

Cecchetti W, Guazzieri C, Tasca A, Dal Bianco M, Zattoni F, Pagano F
980 nm Diode Laser and Fiber Optic Resectoscope in Endourological Surgery
European Biomedical Optics Week, BiOS Europe ’96

 

So why is 970nm wavelength so important?

  •   Tissue can be readily vaporized without charring
  •   Precise cuts with little or no bleeding can be obtained
  •   Good absorption in hemoglobin and oxy-hemoglobin
  •   Ten times more absorption in water than 810 nm
    • The increase in water absorption uses less conductive energy from a hot tip to the use of radiant energy for ablation
  • Uses absorption of radiant energy to enhance vaporization compared to primarily using conductive (heat) energy
  • combination of coagulation, precise tissue ablation and controlled depth penetration
    • Can provide patients with reduced post-operative pain and swelling with enhanced healing time
  • High absorption in water means that water can be used for cooling
    • Reduces the heat conduction from the laser fiber to the surrounding tissue
    • Reduces the conduction of excess heat through the tissue caused by a typically long laser pulse thus reducing excess thermal damage
    • Reduces collateral damage to surrounding tissue that is not targeted for treatment