Which mechanism best explains how capacitive diathermy delivers energy to tissue?

• A. Electrical field between two plates drives current through tissue
• B. Sound waves mechanically heat tissue
• C. Magnetic resonance heating
• D. Visible light heating

Answer: (A)

Capacitive diathermy heats tissue through dielectric heating caused by an alternating electric field created between two plates. The high-frequency field causes polar molecules (like water) and ions in tissue to continuously reorient and move in response to the changing field. This molecular friction converts electrical energy into heat within the tissue. Heating occurs due to the tissue’s dielectric properties, not primarily because a large bulk current flows. This is distinct from heating by sound waves (acoustic), magnetic resonance effects, or visible light. So the energy delivery is best explained by the electric field between the plates driving dielectric heating in tissue.