Which of the following is a listed use of non-thermal ultrasound?

• A. Nerve regeneration
• B. Improved joint flexibility
• C. Bone healing
• D. Hair growth

Answer: (C)

Non-thermal ultrasound uses mechanical energy to stimulate tissue healing without raising tissue temperature. The pulsed, low‑intensity form creates micro-currents and acoustic streaming that influence cell membranes and signaling pathways, encouraging repair processes without heating the area. For bone healing, this mechanical stimulus accelerates osteoblast activity, collagen deposition, and angiogenesis, helping fracture repair proceed more quickly. Among the options, bone healing is the established listed use for non-thermal ultrasound because of this specific effect on bone biology. Nerve regeneration, joint flexibility, and hair growth are not recognized standard listed uses for non-thermal ultrasound within typical clinical guidelines, so they don’t fit as the best choice.