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
According to the theory of selective photothermolysis, the pulse duration should be:
Answer: Equal to or shorter than the thermal relaxation time of the target
Pulse duration at or below the target's thermal relaxation time confines heat to the chromophore, preventing collateral tissue damage.
Which parameter describes the total energy delivered per unit area during a laser treatment?
Answer: Fluence (J/cm²)
Fluence, measured in joules per square centimeter, represents the total energy deposited per unit area and is a key determinant of treatment efficacy.
Increasing the spot size of a laser beam while maintaining the same fluence will generally:
Answer: Increase depth of penetration due to reduced scatter effects
Larger spot sizes reduce lateral scatter at the beam edges, allowing photons to penetrate deeper into tissue at equivalent fluences.
Q-switching in laser technology achieves extremely short, high-peak-power pulses primarily for:
Answer: Tattoo and pigmented lesion removal via photomechanical effect
Q-switched lasers generate nanosecond pulses with extreme peak powers that shatter pigment particles via photomechanical (acoustic) waves rather than thermal heating.
A laser's thermal relaxation time is primarily determined by:
Answer: The size of the target chromophore
Thermal relaxation time scales with the square of the target's diameter, so larger targets (like hair follicles) have longer thermal relaxation times than smaller targets (like melanosomes).
Dynamic cooling devices (DCD) spray cryogen on skin immediately before each laser pulse primarily to:
Answer: Protect the epidermis from thermal injury during treatment
Pre-pulse cryogen spray cools the epidermis selectively, allowing higher fluences to be used safely while protecting melanin-rich epidermal cells.
When treating tattoos with a Q-switched Nd:YAG 1064 nm laser, which ink color responds least effectively?
Answer: Green and yellow
Green and yellow inks absorb poorly at 1064 nm; they require different wavelengths such as 532 nm or 694 nm for effective fragmentation.