Ultrasonic characterization of biological tissues in the temperature range of 26éC to 50éC

This work describes the methodology employed to measure the ultrasonic propagation speed and the ultrasonic attenuation coefficient in the temperature range of 26degC to 50degC, in increments of 2degC, of three porcine biological tissues in vitro: fat, muscle and liver. The characterization was carried out by heating the container with saline solution within a thermostatic bath using the pulse - echo technique, the transducer which sends the pulse and gets the echoes has in front of it 1 mm needles to work as reflectors. The results show, in first term, the echoes generated by the needles. Because the echoes move with the temperature increment, the ultrasonic propagation speed and the attenuation coefficients depending on the temperature can be obtained for the three analyzed tissues. The ultrasonic propagation speed of the three tissues had an almost lineal behavior in the range of temperature while the attenuation coefficient showed peaks throughout most of the range.