<i>In Vivo</i> Temperature Dependence of Ultrasound Speed in Tissue and its Application to Noninvasive Temperature Monitoring

Abstract

Measurements of the speed of ultrasound as a function of temperature in the 35 °C to 45 °C range were made on mammalian (canine) tissue both in vitro and in vivo at 5 MHz using a pulsed transmission technique. Cored samples coinciding with the ultrasonically irradiated tissue were obtained and assayed for water and total lipid content. Results indicate about 2 percent agreement between in vivo and in vitro data, and that, on the basis of kidney data, lipid content and temperature coefficient of ultrasound speed are more highly correlated (0.76 correlation coefficient) than are lipid content and speed of sound (0.17 correlation coefficient).