CLT Laser Technology & Equipment 2 — Questions and Answers
Question 1: Which laser wavelength is most specifically absorbed by oxyhemoglobin, making it ideal for treating vascular lesions?
- 532 nm (KTP) (Correct answer)
- 1064 nm (Nd:YAG)
- 10,600 nm (CO2)
- 755 nm (Alexandrite)
Correct answer: 532 nm (KTP)
The 532 nm KTP laser wavelength corresponds to a peak absorption band of oxyhemoglobin, making it highly effective for vascular lesion treatments.
Question 2: What does the term 'fluence' refer to in laser therapy?
- Energy delivered per unit area (J/cm²) (Correct answer)
- Pulse repetition rate in Hz
- Peak power output in watts
- Spot size diameter in millimeters
Correct answer: Energy delivered per unit area (J/cm²)
Fluence, measured in J/cm², describes the energy density delivered to a target tissue and is a critical parameter for achieving therapeutic outcomes.
Question 3: A diode laser used for hair removal most commonly operates at which wavelength range?
- 800–810 nm (Correct answer)
- 532–585 nm
- 2940 nm
- 308–351 nm
Correct answer: 800–810 nm
Diode lasers for hair removal typically emit at 800–810 nm, a wavelength with good melanin absorption and deeper dermal penetration than shorter wavelengths.
Question 4: Which component of a laser system is responsible for providing the energy that excites the gain medium?
- Pump source (Correct answer)
- Resonator cavity
- Output coupler
- Beam expander
Correct answer: Pump source
The pump source (e.g., flashlamp or diode array) supplies energy to excite electrons in the gain medium to higher energy states necessary for lasing.
Question 5: What is the primary purpose of a Q-switch in a laser system?
- To produce very short, high-peak-power pulses (Correct answer)
- To adjust the beam spot size
- To cool the laser crystal
- To filter unwanted wavelengths
Correct answer: To produce very short, high-peak-power pulses
A Q-switch allows energy to build up in the gain medium and then releases it in an extremely brief, high-peak-power pulse ideal for tattoo and pigment removal.
Question 6: Which type of optical fiber is most commonly used to deliver Nd:YAG laser energy in medical applications?
- Silica step-index fiber (Correct answer)
- Hollow metallic waveguide
- Sapphire-tipped fiber
- Germanium fiber
Correct answer: Silica step-index fiber
Silica step-index fibers efficiently transmit the 1064 nm Nd:YAG wavelength and are durable enough for clinical use.
Question 7: If a laser has a pulse duration shorter than the thermal relaxation time of the target chromophore, the treatment principle applied is called:
- Selective photothermolysis (Correct answer)
- Photobiomodulation
- Ablative resurfacing
- Photodynamic therapy
Correct answer: Selective photothermolysis
Selective photothermolysis uses pulse durations shorter than the target's thermal relaxation time to confine heat damage to the chromophore while sparing surrounding tissue.
CLT Laser Technology & Equipment 2
Which laser wavelength is most specifically absorbed by oxyhemoglobin, making it ideal for treating vascular lesions?