Lasers
Last modified: 31 August 2022, 1:19:12 PM AEST
Gems1 / 7
- LASER = Light Amplification by Simulated Emission of Radiation
Mechanism2 / 7
- emission of a wavelength of high-energy light
- wavelength is measured in nanometres (nm)
Notes3 / 7
-
CO2 laser
- most common in ENT surgery
- infrared light produced is absorbed by biologic media (blood, solid tissues, water)
- minimal penetration depth = only 0.2 mm
- invisible to human eye
- produces intense thermal injury
-
Nd:Yag laser = Neodymium yttrium aluminium garnet
-
Holmium:YAG laser
- photo-mechanical
- extremely intense but very brief pulse of laser
- photoacoustic disruption
- for tissue ablation / lithotripsy
-
Excimer = Argon:Florine laser
- for corneal reshaping
- laser breaks down covalent bonds
- photo-dissociation = non-thermal ablation
Classes of lasers4 / 7
- from ANSI Z-136.1-2007
- Class I
- CD-ROM players
- Class 2
- CW and repetitive-pulse lasers
- can emit accessible energy exceeding Class 1 AEL
- not exceeding 1 mW
- eg = supermarket point-of-sale scanner
- Class 3R
- only a hazard if collected and focused in eye
- Laser pointers
- Class 4
- most dangerous
Tissue Penetration5 / 7
- Argon = 0.5 microns
- strong absorption by Hb
- Nd:YAG 1.06 microns
- no strong absorption
- used in SLT =
- the preferred laser for Selective Laser Trabeculoplasty
- has replaced ALT = Argon Laser Trabeculoplasty
- CO2 = 10.6 microns
- very strong absorption by water
- KTP = Potassium Titanyl Phosphate
- Facial vascular lesions, eg. port wine stain, telangiectasia
-
PDL = Pulsed Dye Lasers
Laser Safety6 / 7
- OT Room
- Laser warning light
- Shutters
- Signs
- PPE
- Googles = ensure wavelength-appropriate
- Staff
- Training
- Laser Safety Lead