CLT Laser Modalities & Applications 2 — Questions and Answers
Question 1: Which laser wavelength is most selectively absorbed by oxyhemoglobin, making it ideal for treating vascular lesions?
- 532 nm KTP (Correct answer)
- 1064 nm Nd:YAG
- 2940 nm Er:YAG
- 10,600 nm CO2
Correct answer: 532 nm KTP
The 532 nm KTP laser targets oxyhemoglobin's absorption peak, making it highly effective for superficial vascular lesions such as telangiectasias.
Question 2: A Fitzpatrick skin type V patient requires laser hair removal. Which device minimizes the risk of post-inflammatory hyperpigmentation?
- 755 nm Alexandrite
- 694 nm Ruby
- 1064 nm Nd:YAG (Correct answer)
- 532 nm KTP
Correct answer: 1064 nm Nd:YAG
The 1064 nm Nd:YAG laser penetrates deeper with less epidermal melanin absorption, making it the safest choice for darker skin types.
Question 3: What is the primary chromophore targeted by the 2940 nm Er:YAG laser?
- Melanin
- Oxyhemoglobin
- Water (Correct answer)
- Tattoo ink
Correct answer: Water
The 2940 nm wavelength coincides with water's peak absorption, causing precise tissue ablation used in skin resurfacing procedures.
Question 4: Pulsed dye laser (PDL) at 585–595 nm is the gold standard for treating which condition?
- Nevus of Ota
- Port wine stains (Correct answer)
- Café-au-lait macules
- Dermal tattoos
Correct answer: Port wine stains
PDL specifically targets oxyhemoglobin in dilated blood vessels, making it the most effective treatment for port wine stain birthmarks.
Question 5: Which laser type uses a solid-state crystal medium doped with neodymium ions to produce its output?
- CO2 laser
- Diode laser
- Nd:YAG laser (Correct answer)
- Argon laser
Correct answer: Nd:YAG laser
The Nd:YAG laser uses a neodymium-doped yttrium aluminum garnet crystal as its gain medium, producing 1064 nm radiation.
Question 6: Fractional laser resurfacing differs from traditional ablative resurfacing primarily because it:
- Uses lower fluences across the entire surface
- Creates microscopic treatment zones sparing surrounding tissue (Correct answer)
- Only targets the papillary dermis
- Requires no anesthesia
Correct answer: Creates microscopic treatment zones sparing surrounding tissue
Fractional lasers create columns of treated tissue (microthermal zones) surrounded by untreated skin, enabling faster healing with reduced downtime.
Question 7: A 1320 nm Nd:YAG laser used for non-ablative skin rejuvenation primarily targets which dermal component?
- Melanin in the epidermis
- Water in the dermis to stimulate collagen (Correct answer)
- Oxyhemoglobin in vessels
- Sebaceous gland lipids
Correct answer: Water in the dermis to stimulate collagen
The 1320 nm wavelength selectively heats dermal water, creating controlled thermal injury that stimulates neocollagenesis without ablating the epidermis.
CLT Laser Modalities & Applications 2
Which laser wavelength is most selectively absorbed by oxyhemoglobin, making it ideal for treating vascular lesions?