Normalized-displacement-difference-based approach for thermal lesion size control

A monitoring method for monitoring biological tissue in a monitoring session during a delivery of energy to the biological tissue, comprising:

• providing, from a tissue-monitoring device, probe-driving signals suitable for driving an integrated push-and-track transducer of a measurement probe, which is external to the tissue-monitoring device, in repeatedly providing at least one ultrasonic push pulse that is suitable for displacing biological tissue at a monitoring location, and in providing ultrasonic track pulses suitable for detecting tissue displacement occurring in response to the ultrasonic push pulse at the monitoring location, and suitable for detecting and delivering ultrasonic tissue-response signals relating to the ultrasonic track pulses;
• repeatedly determining from the ultrasonic tissue-response signals in real time and based on the ultrasonic tissue-response signals:
• a current value of a displacement quantity, which is indicative of an amount of tissue displacement detected;
• a current maximum of the displacement quantity since a beginning of the monitoring session;
• a ratio between the value of the displacement quantity and the current maximum of the displacement quantity;
• a current value of a normalized displacement quantity, which uses the ratio between the value of the displacement quantity and the current maximum of the displacement quantity, and whether the normalized displacement quantity has reached a predetermined threshold value of the normalized displacement quantity;
• and
• providing an output signal when the predetermined threshold value of the normalized displacement quantity has been reached.