The initial rate of change in tissue temperature during thermal therapy is primarily determined by?

• A. Time of exposure to the thermal agent
• B. The thermal conductivity of treated tissue
• C. The temp difference between the thermal agent and the tissue being treated
• D. Amount of tissue exposed to the agent

Answer: (C)

The starting pace at which tissue temperature changes during heating is governed by the temperature gradient between the heat source and the tissue. When a thermal agent is brought into contact, heat flows into the tissue at a rate proportional to how big the difference is between the agent’s temperature and the tissue’s temperature. A larger ΔT means a larger heat flux into the tissue, so the temperature climbs more quickly right after contact.

Tissue properties like thermal conductivity, and how much tissue is exposed or how long the exposure lasts, affect how much total heat is transferred or how rapidly heat spreads later on, but the immediate rate of temperature rise is set by the initial temperature difference.