Laser Modalities & Applications Flashcards
7 cards from real CLT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Laser Modalities & Applications flashcards as text
A patient presents with a Nevus of Ota (blue-grey dermal melanosis). Which laser system is best suited for this condition?
Answer: Q-switched Nd:YAG 1064 nm
Q-switched 1064 nm Nd:YAG penetrates deeply to target dermal melanin in Nevus of Ota while sparing surrounding tissue via photomechanical fragmentation.
During laser nail treatment for onychomycosis, the primary mechanism of fungal killing is:
Answer: Photothermal heating raising nail temperature to fungicidal levels
Laser energy heats the nail plate and nail bed to temperatures lethal to Trichophyton fungi (approximately 50°C), without damaging surrounding tissue.
Which scenario represents the HIGHEST risk for laser-induced ocular injury?
Answer: Specular (mirror-like) reflection from a metal surgical instrument
Specular reflections off polished metal surfaces can redirect a high-intensity beam directly toward the eye with minimal energy loss, posing the greatest ocular hazard.
Paradoxical hypertrichosis after laser hair removal is most likely to occur in patients with which characteristic?
Answer: Hormonal imbalances combined with sub-threshold fluences in darker skin types
Sub-therapeutic fluences may stimulate rather than destroy follicles in areas with vellus or fine hair in darker-skinned patients, triggering conversion to terminal hair growth.
The 1540 nm Er:Glass laser used for non-ablative fractional resurfacing primarily affects which skin layer?
Answer: Mid-to-deep dermis with sparing of the epidermis
The 1540 nm wavelength is absorbed by water in the dermis, creating fractional columns of thermal injury in the mid-to-deep dermis while the intact epidermis accelerates healing.
When performing laser tattoo removal on a patient with permanent cosmetic (eyebrow) tattoo containing titanium dioxide (white pigment), the clinician should warn about:
Answer: Paradoxical darkening of the pigment immediately after treatment
Titanium dioxide (TiO₂) can undergo photo-reduction from white to gray-black when irradiated by Q-switched lasers, causing paradoxical darkening that may be permanent or require many additional sessions.
Which statement best describes the difference between picosecond and nanosecond Q-switched lasers for tattoo removal?
Answer: Picosecond lasers use shorter pulses creating stronger photomechanical effects with less thermal injury per pulse
Picosecond pulses (10⁻¹² s) generate greater pressure waves that more efficiently shatter pigment into smaller particles with less heat, often requiring fewer sessions than nanosecond devices.