What is used to induce physiochemical changes in tissues?

• A. Cryotherapy
• B. TENS
• C. Diathermy and Radiation
• D. Ultrasound

Answer: (C)

Physiochemical changes in tissues come from energy being deposited into the tissue, causing changes in temperature, diffusion, enzyme activity, and other chemical processes. Diathermy and radiation deliver electromagnetic energy that penetrates to depth and heats tissues, speeding up chemical reactions, increasing diffusion, and altering tissue properties. This direct energy-driven modification of tissue chemistry is what characterizes diathermy and radiation as inducing physiochemical changes.

Cryotherapy mainly cools tissue to slow metabolic processes and reduce inflammation, which is more about physiological responses to cold than driving chemical changes in tissue structure. TENS changes nerve signaling through electrical stimulation rather than altering tissue chemistry. Ultrasound can produce heating and mechanical effects, but the classic, energy-deposition–driven chemical changes are most clearly associated with diathermy and radiation.