Monitoring temperature elevations in tissues using quantitative ultrasound.

Abstract

High intensity focused ultrasound (HIFU) is a noninvasive technique that has great potential for improving thermal therapies but requires accurate monitoring of lesion formation. Quantitative ultrasound (QUS) is a novel imaging technique that can improve monitoring of HIFU treatment by quantifying tissue changes. Ultrasonic backscatter experiments were performed on tissue‐mimicking phantoms, fresh rabbit liver, and beef liver samples versus increases in temperature from 37 to 50 °C in 1 °C increments. Two parameters were estimated from the backscatter coefficient [effective scatterer diameter (ESD) and effective acoustic concentration (EAC)] and two parameters were estimated from envelope statistics (k parameter and μ parameter) of the backscatter. No significant changes in ESD were observed for the phantoms but the ESD increased by more than 10% with increasing temperature in the liver samples. Significant decreases in EAC of 20%–40% were observed in all the samples. No specific trends were observed in e...