A unified approach for ultrasound-monitored focused ultrasound thermal therapy: Combination of temperature estimation and Nakagami-based necrosis-formation detection

It has been well recognized that echo-time shift of the ultrasound radio-frequency (RF) signals can reflect temperature change during focused ultrasound (FUS) thermal ablation, and thus has potential for treatment monitoring and guidance. Nevertheless, temperature estimates based on this approach become uncertain when temperature rises to tissue necrotic level (> 50°C). To address this, we propose a unified approach that exploits the merits of ultrasonic temperature estimation and Nakagami imaging to provide a total solution for monitoring of FUS thermal therapy. Our previous studies demonstrate the potential of Nakagami visualization of FUS-induced thermal lesions. Here ultrasonic temperature estimation is used to locate treatment region before tissue coagulation occurs while Nakagami imaging is applied to track the thermal lesion formation. In this study, we experimentally demonstrated that ultrasonic temperature estimation and tissue necrosis detection by Nakagami imaging can serve as complementary roles; thus their integration can provide a total solution that fulfills the monitoring of the overall heating process. This work may help to improve the current clinical practice, which uses ultrasound to guide the FUS thermal ablation procedure.