An integrated system for real-time monitoring of temperature changes, cavitation and necrosis inside the tissue at the focus of the HIFU beam using a backscattered ultrasonic signals inducing changes in the electrical power driving the HIFU transducer

Abstract

To address the unclear mechanism of changes in the electrical power driving the HIFU transducer and the challenges in real-time monitoring of treated tissue damage, this paper presents a system for real-time monitoring of driving electric power, focus of the HIFU beam, acoustic cavitation, temperature detection, and necrotic lesion monitoring using voltage and current sensors, cavitation-detecting probes, and temperature sensors. Utilizing the characteristics of backscattered ultrasonic signals, we investigated the mechanism and pattern of changes in the electrical power of the HIFU transducer and examined the relationship between the electrical power driving the HIFU transducer and the temperature, cavitation, and acoustic impedance of the treated tissue. Experimental results demonstrated that the system accurately monitors the output electrical power during treatment, characterizes the intensity of cavitation activity by the amplitude of driving power during sonication, and identifies necrotic lesions by changes in the amplitude of backscattered signals detected in the time interval between sonications. The system can distinguish types of transient changes in the physical properties of the treated tissue in the region of the HIFU beam focus, which is intended to increase the precision of HIFU sonication dose regulation and ensure the safety of treatment. Additionally, it provides a solution for real-time monitoring of cavitation activity and necrotic lesion severity in treated tissue during HIFU treatment.