Laser
Terms
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- Laser is an acronym for what?
- Light Amplification by Stimulated Emission of Radiation
- What is thermal relaxation time?
- The time needed for 50% of the heat to dissipate
- What skin types are the best candidates for laser skin resurfacing?
- Fitzpatrick types I and II, with fine to medium wrinkles
- At which wavelength does the CO2 laser operate?
- 10,600 nm
- What is the chromophore for the CO2 laser?
- Water
- What is the main side effect of the CO2 laser?
- Erythema for 2-4 months
- What wrinkles can be treated with a CO2 laser?
- fine and deeper wrinkles
- At which wavelength does the Er:YAG laser operate?
- 2940 nm
- What is the chromophore for the Er:YAG laser?
- water
- Which laser can be used on areas of very thin skin (like dorsum of hand)?
- Er:YAG laser
- The Er:YAG laser is best for which type of wrinkles?
- fine, superficial wrinkles (lunchtime peel)
- What are the main side effects of the Er:YAG laser?
- erythema for 2-4 weeks, bleeding
- Why does bleeding occur with the Er:YAG laser, but not the CO2 laser?
- The Er:YAG laser is not a coagulating laser
- What are the major absorption peaks for hemoglobin and oxyhemoglobin chromophores?
- 500-1000 nm
- Laser therapy is the treatment of choice for which vascular malformations?
- Capillary vascular malformations
- Which lasers are useful for skin resurfacing?
- Er:YAG laser and CO2
- Which lasers are useful for treatment of vascular lesions?
- Pulsed dye and KTP
- Which lasers are useful for treatment of pigmented skin lesions?
- Q-switched ruby, Q-switched alexandrite, Nd:YAG, frequency-doubled Nd:YAG, and copper bromide (or copper vapor)
- Which lasers are useful for removal of red and orange tattoos?
- Q-switched Nd:YAG and pulsed dye
- Which lasers are useful for removal of all tattoo colors except red and orange?
- Q-switched Alexandrite, Q-switched ruby
- Which lasers are useful for hair removal?
- Long-pulse ruby, long-pulse alexandrite, intense pulsed- light
- Which lasers are useful for tattoo removal except red, orange and green?
- Q-switched Nd:YAG
- What are the most common adverse effects of laser tattoo removal?
- multiple treatments usually necessary, may need more than one laser to target all pigments, hypopigmentation, incomplete removal
- What are the most common adverse effects of laser hair removal?
- requires several treatments, transient erythema, hypopigmentation
- What is the most commonly used laser for capillary malformations (and is also used for telangiectasias)?
- Flashlamp-pumped pulsed dye laser
- At what wavelength does the flashlamp-pumped pulsed dye laser operate?
- 585nm
- What is the mechanism of action of the flashlamp-pumped pulsed dye laser?
- Light absorbed by hemoglobin and oxyhemoglobin heats vessels to over 60 C for 1 ms causing endothelial cell contraction and vessel ablation
- What is the major side effect of the flashlamp-pumped pulsed dye laser?
- purpura for 2-3 weeks
- At what wavelength does the KTP laser operate?
- 532 nm
- What is the main advantage of the KTP laser over the flashlamp-pumped pulsed dye laser?
- purpura rarely occur
- Why is the Argon laser now rarely used in the treatment of vascular malformations?
- High incidence of hypertrophic scarring and hypopigmentation
- How do lasers remove tattoos?
- Rapidly pulsed laser energy (Q-switched mode) penetrates to the level of the papillary dermis and heats particles until they explode. The smaller particles are removed by phagocytosis.
- How long should you wait between treatments for laser tattoo removal?
- 3 weeks (the time it takes for phagocytosis to clear debris from last treatment)
- What happens if tattoos with metal-containing pigments are treated by laser?
- black discoloration instead of removal
- What is the targeted chromophore with laser hair removal?
- Melanin
- What is the main side effect of laser hair removal?
- Hypopigmentation (melanin is the targeted chromophore)
- The laser can remove hair follicles in which phase of the growth cycle?
- anagen
- What is the typical regrowth rate after laser hair removal?
- 10%
- What is the safest way to removed hair for darker skin colors?
- EpiLight (590-1200 nm)
- What laser can be used for hair restoration?
- CO2 laser can be used to create micrograft recipient incisions
- What laser can be used to treat acne scarring?
- Er:YAG
- How long do you wait after isotretinoin (Accutane) treatment before attempting laser acne scar tretment
- 1 year
- How does isotretinoin (accutane) affect laser skin resurfacing?
- Impairs re-epithelialization
- What are the 4 absolute contraindications to laser resurfacing?
- keloids, scleroderma, lupus, isotretinoin (Accutane) use within the previous year
- Name some relative contraindications to laser resurfacing.
- smoking, previous resurfacing, diabetes, prior skin irradiation, active acne, hypertrophic scarring, skin hypersensitivity, pigmentation disorders