Image-Guided Thermal Therapy

By increasing tissue temperature above 40°C, heat can be used to elicit a variety of cellular and physiological eects that can either work in concert with other therapies or be used to induce a direct cytotoxic eect. Two broad categories exist to classify these dierent therapeutic regimes. Mild hyperthermia refers to tissue heating at temperatures of 40-45°C used primarily to enhance and localize the eects of other therapies. Modest temperature elevations maintained for minutes to hours can be used to increase blood ow, induce chemo-or radio-sensitization, increase vessel permeability, or trigger the action of temperature-sensitive drugs. High-temperature thermal therapy, sometimes called thermal ablation, is used to achieve irreversible tissue destruction by applying temperatures greater than 50°C over timescales of seconds to minutes. With recent improvements in the ability to monitor and control treatment, there has been increased clinical interest in both regimes as precisely controlled minimally or noninvasive approaches for the treatment of localized tumors.