Noninvasive temperature estimation by detecting echo-strain change including thermal expansion

This article studies the feasibility of noninvasive temperature estimationby detecting echo-strain including thermal expansion in therapeuticultrasound treatment. This technique evaluates distributions of echo-strainand temperature inside the tissue by detecting echo signals pre- andpost-heating, in combination with the temperature dependence of sound speedand thermal expansion. In the computer simulation and experimental study,echo signals pre- and post-heating are acquired and then the temperatureelevation is evaluated by correlation analysis. Results demonstrate thatthis technique can effectively extend the measured temperature range up to75$^{circ}$C with an accuracy of $pm $2$,^{circ}$C.