Which option is not a nonthermal effect of ultrasound?

Which option is not a nonthermal effect of ultrasound?

• A. Significant direct tissue heating
• B. Increase vascular permeability
• C. Increase fibroblast activity
• D. Stimulation of phagocytosis

Answer: (D)

Nonthermal ultrasound effects come from the mechanical energy of the sound waves, such as cavitation and microstreaming, which alter cell membranes and promote tissue repair without a significant rise in temperature. In contrast, significant direct tissue heating is a thermal effect, produced when ultrasound energy is converted into heat. Increased vascular permeability and increased fibroblast activity are commonly cited nonthermal responses that support healing by enhancing fluid movement and collagen synthesis. Stimulation of phagocytosis is not typically described as a direct nonthermal effect of ultrasound; while immune activity can be involved in healing, phagocytosis is not a primary ultrasound-driven nonthermal mechanism. Therefore, the statement describing stimulation of phagocytosis is not a nonthermal effect.

Nonthermal ultrasound effects come from the mechanical energy of the sound waves, such as cavitation and microstreaming, which alter cell membranes and promote tissue repair without a significant rise in temperature. In contrast, significant direct tissue heating is a thermal effect, produced when ultrasound energy is converted into heat. Increased vascular permeability and increased fibroblast activity are commonly cited nonthermal responses that support healing by enhancing fluid movement and collagen synthesis. Stimulation of phagocytosis is not typically described as a direct nonthermal effect of ultrasound; while immune activity can be involved in healing, phagocytosis is not a primary ultrasound-driven nonthermal mechanism. Therefore, the statement describing stimulation of phagocytosis is not a nonthermal effect.