Which setting would most directly reduce energy delivered to the skin?

Which setting would most directly reduce energy delivered to the skin?

• A. Decreasing energy (J/cm2)
• B. Increasing wavelength (nm)
• C. Increasing pulse width (ms)
• D. Increasing repetition rate (Hz)

Answer: (A)

The main idea is that energy delivered to the skin is governed most directly by fluence—the energy per unit area in each laser pulse. Lowering the fluence reduces the energy deposited in the skin with every pulse, so the overall energy reaching the tissue drops right away. Changing wavelength changes which chromophores absorb the energy and how efficiently hair is targeted versus skin, affecting safety and effectiveness but not necessarily reducing the energy per pulse at the skin surface by itself. Adjusting pulse width changes how long the energy is delivered during each pulse, influencing heating dynamics and tissue response, not the total energy per pulse in the simplest terms. Increasing repetition rate increases how many pulses occur per second, which tends to raise total energy delivered over time rather than reduce the energy in each pulse.

The main idea is that energy delivered to the skin is governed most directly by fluence—the energy per unit area in each laser pulse. Lowering the fluence reduces the energy deposited in the skin with every pulse, so the overall energy reaching the tissue drops right away.

Changing wavelength changes which chromophores absorb the energy and how efficiently hair is targeted versus skin, affecting safety and effectiveness but not necessarily reducing the energy per pulse at the skin surface by itself. Adjusting pulse width changes how long the energy is delivered during each pulse, influencing heating dynamics and tissue response, not the total energy per pulse in the simplest terms. Increasing repetition rate increases how many pulses occur per second, which tends to raise total energy delivered over time rather than reduce the energy in each pulse.