Quantification of temperature and injury response in thermal therapy and cryosurgery.

Research on thermal therapy--the heating of pathological tissue using energy source (radiofrequency, microwave, high-intensity focused ultrasound, or laser energy)--and cryosurgery--the freezing of pathological tissue using either liquid or gaseous cryogens--can be classified into two broad categories: basic science and clinical application. The basic science of thermal therapy and cryosurgery is an interdisciplinary research field involving both biology and engineering. Studies from the perspective of biology mainly focus on determining the thermally induced injury mechanisms at the macromolecular, cellular, and tissue (in vitro and in vivo) levels. Studies from the engineering perspective emphasize how to measure and predict the thermal and injury behavior using engineering tools. This article will give a detailed overview of studies relevant to the basic science of thermal therapy and cryosurgery from both the biology and engineering points of view. This includes the experimental observations of cellular and vascular alterations during and after thermal therapy/cryosurgery and the quantification of thermal histories and corresponding injuries using mathematical models.