Laser - Basics
| What does "LASER" mean? |
LASER is an acronym Light Amplification by Stimulated Emission of Radiation |
| What does it do? |
Lasers are used in hospitals for surgical procedures such
as, cutting tissue, controlling bleeding (gastric ulcers), ophthalmology
(repairing detached retinas) and oncology (destroying tumours). |
| Physiology |
Lasers are able to produce a range of responses in living
tissue, such as various optical interactions, thermal, photo
ablative (separation of molecular bonds), electromechanical
(thunder like shock wave), photochemical (like skin tanning
in the sunlight) and biostimulation (e.g. improving circulation
by cellular stimulation). The laser interaction with tissue
can be reflected, scattered (change in lights direction), absorbed
(the light energy is transferred into the tissue) and transmitted
(no loss of energy while going through tissue). This interaction
depends on the wavelength, power density and pulse duration
of the laser light. |
| How it works |
Four main components of a laser are: 1. The actual substance or active medium in which the laser action takes place, this can be a solid, liquid, or gas, which determines the type of laser (eg. Helium-Neon, Carbon Dioxide, Nd:YAG, Ruby) 2. The optical cavity contains the substance or active medium and has mirrors at each end to amplify the light. One of the mirrors is only a partial mirror and it is through this that the laser beam emerges. 3. External energy source in the form of intense light or voltage is delivered to the active medium to excite the atoms that give off light when stimulated, triggering the laser process. 4. Laser delivery system includes a form of control (e.g. power, exposure time), delivery path (e.g. fibre optics, mirrors and tube, beam spot size) and method of aiming the beam (with another low power, visible safe laser) to the desired surgical site. The surgical laser will emit a concentrated, single wavelength beam, in phase and in the same direction aimed at tissue to provide the desired effect. |
| Units of measurement |
Power: Watts |
| Typical values |
Wave lengths: Argon 490-510nm, Helium-neon, 630nm, Nd-YAG 1064nm, CO2 10600 nm |
| Picture of equipment |
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 Alcon - Laser |
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