VTCT level 5 core parameters Exam
Questions and CORRECT Answers
What is Pulse Width (Pulse Duration) in tattoo removal? - CORRECT ANSWERS The amount of
time the laser beam is actually "on" and hitting the skin per pulse. In tattoo removal, this is
measured in nanoseconds or picoseconds.
What is TRT (Thermal Relaxation Time) and why does it matter? - CORRECT ANSWERS The
time it takes for a target (like ink) to lose 50% of its heat. The laser's pulse width must be shorter
than the ink's TRT, or heat will escape and burn the surrounding skin.
What is Hertz (Hz) in laser settings? - CORRECT ANSWERS The repetition rate, meaning how
many laser pulses are delivered per second (e.g., 5 Hz = 5 zaps per second). It controls treatment
speed, not pulse strength.
What is Energy and how is it measured? - CORRECT ANSWERS The total amount of raw laser
power delivered in a single pulse. It is measured in Joules (J).
What is Fluence and how is it measured? - CORRECT ANSWERS The concentration of laser
energy delivered over a specific area (energy density). It is measured in Joules per square centimeter
(J/cm^2).
What happens to Fluence if you decrease the Spot Size but keep the Energy (Joules) the same? -
CORRECT ANSWERS Fluence increases. Shoving the same energy into a smaller area makes the
beam much more concentrated and intense.
Questions and CORRECT Answers
What is Pulse Width (Pulse Duration) in tattoo removal? - CORRECT ANSWERS The amount of
time the laser beam is actually "on" and hitting the skin per pulse. In tattoo removal, this is
measured in nanoseconds or picoseconds.
What is TRT (Thermal Relaxation Time) and why does it matter? - CORRECT ANSWERS The
time it takes for a target (like ink) to lose 50% of its heat. The laser's pulse width must be shorter
than the ink's TRT, or heat will escape and burn the surrounding skin.
What is Hertz (Hz) in laser settings? - CORRECT ANSWERS The repetition rate, meaning how
many laser pulses are delivered per second (e.g., 5 Hz = 5 zaps per second). It controls treatment
speed, not pulse strength.
What is Energy and how is it measured? - CORRECT ANSWERS The total amount of raw laser
power delivered in a single pulse. It is measured in Joules (J).
What is Fluence and how is it measured? - CORRECT ANSWERS The concentration of laser
energy delivered over a specific area (energy density). It is measured in Joules per square centimeter
(J/cm^2).
What happens to Fluence if you decrease the Spot Size but keep the Energy (Joules) the same? -
CORRECT ANSWERS Fluence increases. Shoving the same energy into a smaller area makes the
beam much more concentrated and intense.
