Therapeutic Laser Applications Flashcards

Which statement best describes 'photobiomodulation' (PBM) compared to photodynamic therapy (PDT)?

Answer: PBM uses light to stimulate healing without photosensitizers; PDT uses photosensitizers to destroy pathological tissue

PBM uses light alone to stimulate cellular healing processes, while PDT requires a photosensitizing agent that is activated by light to destroy abnormal tissue.

A therapist treats a patient's lumbar paraspinal muscles with a 4 W, 980 nm diode laser. What precaution is most critical due to the high water absorption at this wavelength?

Answer: Ensure continuous probe movement to prevent localized thermal injury

At 980 nm, water absorbs significantly more energy; at high power settings, a stationary probe can cause localized thermal burns requiring continuous movement.

What does the term 'coherence' mean in the context of laser light, and why is it clinically relevant?

Answer: All photons travel in the same phase and direction; it contributes to precise energy delivery and tissue penetration

Laser coherence means photons are in phase and collimated, enabling precise, concentrated energy delivery that penetrates tissue differently than incoherent light sources.

When applying laser therapy over a joint with a metal implant (e.g., knee replacement), the therapist should:

Answer: Use caution and monitor for heat sensation, as metal may conduct and concentrate heat

Metal implants can absorb and conduct laser energy as heat to surrounding tissue; therapists should monitor patient feedback for warming sensations and adjust accordingly.

The therapeutic effect of laser on edema reduction is primarily mediated by:

Answer: Stimulation of lymphatic flow and modulation of vascular permeability

Photobiomodulation stimulates lymphatic vessel activity and reduces vascular permeability, facilitating reabsorption and drainage of interstitial edema.

Which of the following best describes 'biphasic dose response' in laser therapy?

Answer: Low doses stimulate biological activity while excessive doses inhibit it

The biphasic dose response (Arndt-Schulz principle) means low-to-moderate energy doses stimulate healing while very high doses can suppress or damage tissue.

A patient is 8 weeks postoperative from ACL reconstruction. What is the primary goal of laser therapy at this stage of rehabilitation?

Answer: Stimulate collagen maturation, reduce scar tissue formation, and support tissue remodeling

At 8 weeks post-ACL surgery, the remodeling phase benefits from laser therapy to stimulate collagen maturation and reduce excessive scar formation in the healing graft.