Thermal dosimetry and temperature measurements.

A crucial ingredient of any hyperthermia procedure is the accurate measurement of achieved temperature. In this paper, we present some accuracy and resolution suggestions and address the problem of temperature measurements when electromagnetic energy is used as the mode of heating. In such cases, conventional metallic thermometers can cause severe errors due to reradiated fields, high internal healing, and electronic interference. To avoid these problems, several groups have developed either high-resistance lead thermometers or optical-fiber probes using a variety of sensors, including birefringent and semiconductor crystals. A new noninvasive approach uses ultrasound-computed tomography and relies upon the change in the speed of sound versus temperature to achieve maps of internal tissue temperature.