OBT Photobiomodulation Mechanisms & Cellular Effects 3

Question 1

Which of the following wavelength ranges is generally considered optimal for deeper tissue penetration in photobiomodulation?

Accepted Answer

780–1100 nm (near-infrared)

Answer

400–500 nm

Answer

500–600 nm

Answer

600–700 nm

Question 2

The term 'coherence' in laser light refers to:

Accepted Answer

Uniform phase relationship among photons, producing an ordered wavefront

Answer

The ability of light to cause ionization

Answer

The concentration of photons in a beam

Answer

The speed at which photons travel through tissue

Question 3

During the inflammatory phase of wound healing, photobiomodulation primarily assists by:

Accepted Answer

Modulating macrophage polarization toward the M2 anti-inflammatory phenotype

Answer

Prolonging the inflammatory response to maximize immune activity

Answer

Increasing neutrophil recruitment to the wound site

Answer

Stimulating mast cell degranulation

Question 4

Which parameter determines how quickly photobiomodulation energy is delivered to tissue?

Accepted Answer

Irradiance or power density (mW/cm²)

Answer

Fluence (J/cm²)

Answer

Wavelength (nm)

Answer

Coherence length

Question 5

Photobiomodulation-induced upregulation of heat shock proteins (HSPs) in cells primarily contributes to:

Accepted Answer

Cellular protection, protein folding, and stress resistance

Answer

DNA mutation and genomic instability

Answer

Apoptosis of healthy surrounding cells

Answer

Reduction in mitochondrial membrane potential

Question 6

When comparing pulsed and continuous wave delivery modes in photobiomodulation, pulsed mode is theorized to offer an advantage because:

Accepted Answer

Duty cycles may allow tissue cooling and reduce inhibitory effects at high peak powers

Answer

It eliminates the need for calculating fluence

Answer

Pulsed light always produces deeper penetration than continuous wave

Answer

It bypasses the biphasic dose response entirely

Question 7

The concept of 'retrograde axonal signaling' in photobiomodulation neuroscience refers to:

Accepted Answer

Signals generated at the irradiated peripheral nerve site traveling back to the cell body in the dorsal root ganglion

Answer

Light traveling backward through optical fibers in neural tissue

Answer

Inhibition of motor neuron firing by photons

Answer

Anterograde transport of chromophores along axons